Lung cancer screening in Brazil: recommendations from the Brazilian Society of Thoracic Surgery, Brazilian Thoracic Association, and Brazilian College of Radiology and Diagnostic Imaging / Recomendações da Sociedade Brasileira de Cirurgia Torácica, Sociedade Brasileira de Pneumologia e Tisiologia e Colégio Brasileiro de Radiologia e Diagnóstico por Imagem para o rastreamento do câncer de pulmão no Brasil

ABSTRACT Although lung cancer (LC) is one of the most common and lethal tumors, only 15% of patients are diagnosed at an early stage. Smoking is still responsible for more than 85% of cases. Lung cancer screening (LCS) with low-dose CT (LDCT) reduces LC-related mortality by 20%, and that reduction reaches 38% when LCS by LDCT is combined with smoking cessation. In the last decade, a number of countries have adopted population-based LCS as a public health recommendation. Albeit still incipient, discussion on this topic in Brazil is becoming increasingly broad and necessary. With the aim of increasing knowledge and stimulating debate on LCS, the Brazilian Society of Thoracic Surgery, the Brazilian Thoracic Association, and the Brazilian College of Radiology and Diagnostic Imaging convened a panel of experts to prepare recommendations for LCS in Brazil. The recommendations presented here were based on a narrative review of the literature, with an emphasis on large population-based studies, systematic reviews, and the recommendations of international guidelines, and were developed after extensive discussion by the panel of experts. The following topics were reviewed: reasons for screening; general considerations about smoking; epidemiology of LC; eligibility criteria; incidental findings; granulomatous lesions; probabilistic models; minimum requirements for LDCT; volumetric acquisition; risks of screening; minimum structure and role of the multidisciplinary team; practice according to the Lung CT Screening Reporting and Data System; costs versus benefits of screening; and future perspectives for LCS.

RESUMO O câncer de pulmão (CP) é uma das neoplasias mais comuns e letais no Brasil, e apenas 15% dos pacientes são diagnosticados nos estágios iniciais. O tabagismo persiste como o responsável por mais de 85% de todos os casos. O rastreamento do CP (RCP) por meio da TC de baixa dosagem de radiação (TCBD) reduz a mortalidade do CP em 20%, e, quando combinado com a cessação do tabagismo, essa redução chega a 38%. Na última década, diversos países adotaram o RCP como recomendação de saúde populacional. No Brasil, embora ainda incipiente, a discussão sobre o tema é cada vez mais ampla e necessária. Com o intuito de aumentar o conhecimento e estimular o debate sobre o RCP, a Sociedade Brasileira de Cirurgia Torácica, a Sociedade Brasileira de Pneumologia e Tisiologia e o Colégio Brasileiro de Radiologia e Diagnóstico por Imagem constituíram um painel de especialistas para elaborar as recomendações para o RCP. As recomendações aqui apresentadas foram baseadas em revisão narrativa da literatura, com ênfase em grandes estudos populacionais, em revisões sistemáticas e em recomendações de diretrizes internacionais, sendo construídas após ampla discussão pelo grupo de especialistas. Os temas revisados foram os seguintes: porque rastrear, considerações gerais sobre tabagismo, epidemiologia do CP, critérios de elegibilidade, achados incidentais, lesões granulomatosas, modelos probabilísticos, requisitos mínimos da TCBD, aquisições volumétricas, riscos do rastreamento, estrutura mínima e papel da equipe multidisciplinar, conduta segundo o Lung CT Screening Reporting and Data System (Lung-RADS), custos vs. benefícios e perspectivas do rastreamento.

Metodologías de Medición de Volumetría Hepática / Methodologies For Measuring Hepatic Volumetry

Lograr determinar el volumen total de un hígado (VHT), o volumetría hepática, pasa a ser de relevancia en diversas situaciones, tales como, vigilancia del progreso de una enfermedad de carácter crónico, planificación de resecciones y trasplantes hepáticos; y observación del clearance hepático de algunos fármacos hepatotropos. La VHT se puede realizar utilizando métodos de segmentación en el curso de una tomografía computarizada (TC), ya sean estos manual, automáticos, y semiautomáticos; mediante resonancia nuclear (RN), utilizando softwares de distintas generaciones (1ª a 4ª). La medición de VHT está indicada en pacientes sometidos a resecciones hepáticas mayores, en el contexto del tratamiento de neoplasias (carcinoma hepatocelular, colangiocarcinoma, metástasis hepáticas o tumores benignos de gran tamaño), abscesos (piogénicos, amebianos), y después de un traumatismo hepático complejo; así como también en la etapa preoperatoria de un trasplante hepático. El objetivo de este manuscrito fue generar un documento de estudio sobre métodos para determinar volumetría hepática.

SUMMARY: Being able to determine the total hepatic volume (THV), or THV, becomes relevant in various situations, such as monitoring the progress of a chronic disease, planning resections and liver transplants; and observation of the hepatic clearance of some hepatotropic drugs. THV can be performed using segmentation methods in the course of a computed tomography (CT), whether manual, automatic, or semi-automated; by nuclear resonance (NR), using software from different generations (1st to 4st). THV measurement is indicated in patients undergoing major liver resections, in the context of treatment of neoplasms (hepatocellular carcinoma, cholangiocarcinoma, liver metastases or large benign tumors), abscesses (pyogenic, amoebic), and after liver trauma complex, as well as in the preoperative stage of a liver transplant. The aim of this manuscript was to generate a study document regarding methods for determine hepatic volumetry.

Achados tomográficos incidentais de calcificações coronarianas: um estudo de prevalência na região sul do Brasil / Incidental tomographic findings of coronary artery calcifications: a prevalence study in southern Brazil

Fundamento: As calcificações de artérias coronárias (CAC) mostram-se como fator preditivo de doenças cardiovasculares (DCV). A tomografia computadorizada (TC) de tórax com protocolo de aquisição de baixa dose apresenta acurácia na identificação de CAC e propicia achados incidentais dessas calcificações, que são comumente negligenciados. Este estudo analisará a prevalência de achados incidentais de calcificação em artérias coronárias em indivíduos não cardiopatas submetidos à TC de tórax. Métodos: Estudo transversal consecutivo de caráter analítico e descritivo. Foram incluídos indivíduos de ambos os sexos que realizaram TC de tórax por encaminhamento, acima de 18 anos e não cardiopatas. A coleta de dados foi realizada por meio de prontuários e ficha de anamnese auto aplicada. As variáveis referentes às CAC e à extensão do comprometimento foram obtidas a partir da reavaliação das imagens de TC de tórax disponíveis no sistema da instituição. Os exames foram anonimizados e avaliados por dois médicos radiologistas experientes. Considerou-se como estatisticamente significativo p≤0,05. Resultados: Foram analisados 397 exames. Encontrou-se prevalência de calcificações em 176 (44%) dos casos. A existência dessas calcificações coronárias está relacionada à idade (p<0,001). As calcificações possuem relação com o sexo (p = 0,03) com maior razão de chance de desenvolvimento em homens (odds ratio [OR] = 1,55). O tabagismo (p<0,001), o sedentarismo (p<0,001), a hipertensão arterial sistêmica (p<0,001), o diabetes mellitus (p = 0,04) e as dislipidemias (p<0,001) mostraram associação positiva. Conclusão: A prevalência de achados incidentais de CAC foi de 44%; variam em maior número entre leve e grave; maior razão de chance no sexo masculino e aumento da prevalência com a idade. Portanto, a TC de tórax mostra-se um efetivo método para avaliar as CAC, e juntamente com a história clínica do paciente pode ser utilizada para medir os fatores de risco para doenças cardiovasculares e intervir no desfecho do quadro.(AU)

Introduction: Coronary artery calcifications (CAC) are shown to be a predictive factor of cardiovascular diseases. Computed tomography (CT) of the chest with a low-dose acquisition protocol is accurate in identifying CAC and provides incidental findings of these calcifications, which are commonly overlooked. This study will analyze the prevalence of incidental findings of calcification in coronary arteries in non-cardiac individuals undergoing chest CT. Methods: Consecutive cross-sectional study of an analytical and descriptive nature. Individuals of both genders who underwent chest CT by referral, over 18 years of age and without heart disease were included. Data collection was carried out using medical records and a self-applied anamnesis form. The variables referring to the CAC and the extension of the impairment were obtained from the reassessment of the chest CT images available in the institution's system. The exams were anonymized and evaluated by two experienced radiologists. P≤0.05 was considered statistically significant. Results: 397 exams were analyzed. A prevalence of calcifications was found in 176 (44%) of the cases. The existence of these coronary calcifications is related to age (p<0.001). Calcifications are related to gender (p = 0.03) with a higher odds ratio of development in men (odds ratio [OR] = 1.55). Smoking (p<0.001), sedentary lifestyle (p<0.001), systemic arterial hypertension (p<0.001), Diabetes Mellitus (p = 0.04), and dyslipidemia (p<0.001) showed a positive association. Conclusion: The prevalence of incidental CAC findings was 44%; vary in greater numbers between mild and severe; higher odds ratio in males and increased prevalence with age. Therefore, chest CT proves to be an effective method to assess CAC, and together with the patient's clinical history, it can be used to measure risk factors for CVD and intervene in the outcome of the condition.(AU)

Asociación entre calidad del tratamiento endodóntico y periodontitis apical, evaluada mediante Tomografía Computarizada de Haz Cónico en una población colombiana / Association between endodontic treatment quality and apical periodontitis assessed through cone beam computarized tomography in a colombian population / Associação entre qualidade do tratamento endodôntico e periodontite apical, avaliada por tomografia computadorizada de feixe cônico em uma população colombiana

Introducción: La prevalencia de periodontitis apical en dientes con tratamiento endodóntico oscila entre el 35 y el 60%, se ha encontrado una fuerte asociación con respecto al grado de inflamación sistémica generada por la periodontitis apical, como por ejemplo altos niveles de citoquinas proinflamatorias, proteína C reactiva e interleuquina 6; estudios refieren que un tratamiento endodóntico adecuado puede reducir los niveles de proteína C reactiva en individuos sanos y con periodontitis apical. Objetivo: Evaluar la frecuencia de periodontitis apical en una población adulta colombiana seleccionada y su correlación con la calidad del tratamiento endodóntico. Materiales y métodos: Estudio observacional analítico de corte transversal, se determinó la frecuencia de periodontitis apical en 318 CBCT (Tomografía Computarizada de Haz Cónico), de pacientes de una subpoblación de Bucaramanga y Medellín y evaluó la asociación de la calidad del tratamiento endodóntico con el estado periapical. Resultados: Sólo el 37,66% de los dientes evaluados fueron considerados sanos; el 44,81% se clasificaron como tratamiento endodóntico adecuado. La calidad del tratamiento endodóntico influyó significativamente en la condición del periodonto apical. Conclusiones: Los tratamientos evaluados presentaron alta frecuencia de periodontitis apical, la cual se asoció en buena parte a la alta frecuencia de tratamientos endodónticos inadecuados.

Introduction: The prevalence of apical periodontitis in teeth with endodontic treatment ranges between 35% and 60%, and a strong association has been found with respect to high levels of systemic inflammation markers (pro-inflammatory cytokines, protein C-reactive and interleukin 6) caused by apical periodontitis. Studies have shown that an adequate endodontic treatment can reduce C-reactive protein levels in healthy individuals and those with apical periodontitis. Objective: To evaluate the frequency of apical periodontitis in a selected Colombian adult population and its correlation with the quality of endodontic treatment. Materials and methods: Observational, analytical, cross-sectional study. The frequency of apical periodontitis was determined in 318 CBCTs of patients from Bucaramanga and Medellin, and the association between quality of endodontic treatment and periapical status was analyzed. Results: Only 37.66% of the observed teeth were considered healthy, whereas 44.81% were classified as teeth with appropriate endodontic treatment. Quality of endodontic treatment significantly affected the condition of the apical periodontium. Conclusions: The analyzed treatments had a high apical periodontitis frequency, which was associated with a high frequency of inadequate endodontic treatments.

Introdução: A prevalência de periodontite apical em dentes com tratamento endodôntico varia entre 35 e 60 %, uma forte associação foi encontrada com relação ao grau de inflamação sistêmica gerada pela periodontite apical, como altos níveis de citocinas pró-inflamatórias, proteína C reativa e interleucina 6; estudos relatam que o tratamento endodôntico adequado pode reduzir os níveis de proteína C-reativa em indivíduos saudáveis ​​e naqueles com periodontite apical. Objetivo: Avaliar a frequência da periodontite apical em uma população adulta colombiana selecionada e sua correlação com a qualidade do tratamento endodôntico. Materiais e métodos: Estudo transversal analítico observacional; a frequência de periodontite apical foi determinada em 318 CBCT de pacientes de uma subpopulação de Bucaramanga e Medellín, foi avaliada a associação da qualidade do tratamento endodôntico com o estado periapical. Resultados: Apenas 37,66% dos dentes avaliados foram considerados saudáveis, 44,81% dos dentes foram classificados como tratamento endodôntico adequado. A qualidade do tratamento endodôntico influenciou significativamente a condição do periodonto apical. Conclusões: Os tratamentos avaliados apresentaram alta frequência de periodontite apical, que foi amplamente associada à alta frequência de tratamentos endodônticos inadequados.

Crohn's disease: review and standardization of nomenclature / Doença de Crohn: revisão e padronização da nomenclatura

Abstract Crohn's disease is an inflammatory bowel disease that can affect any segment of the gastrointestinal tract. It has a variable clinical course, with alternating periods of disease activity and remission. Because the incidence and prevalence of Crohn's disease have been increasing, evaluation by imaging methods has become more important. The most widely used methods are computed tomography enterography, magnetic resonance enterography (as an elective examination), and contrast-enhanced computed tomography (in the context of emergency). Computed tomography enterography and magnetic resonance enterography are useful for diagnosis, follow-up, evaluation of complications, and prognosis. Both can be used in order to evaluate the small bowel loops and the associated mesenteric findings, as well as to evaluate other abdominal organs. They both also can detect signs of disease activity, fibrosis, penetrating disease, and complications. The interpretation of such changes is essential to the multidisciplinary approach, as is the standardization of the nomenclature employed in the reports. In this paper, we review and illustrate the imaging findings of Crohn's disease, using the standardized nomenclature proposed in the multidisciplinary consensus statement issued by the Society of Abdominal Radiology, the Society of Pediatric Radiology, and the American Gastroenterology Association, with recommendations for descriptions, interpretations, and impressions related to those findings.

Resumo Doença de Crohn é uma doença inflamatória intestinal que pode acometer qualquer segmento do trato gastrointestinal, com curso clínico variado, alternando períodos de atividade de doença e remissão. Sua incidência e prevalência vêm aumentando, tornando a avaliação por métodos de imagem mais importante. Os métodos mais utilizados são enterotomografia computadorizada, enterorressonância magnética eletivamente e tomografia computadorizada com contraste no contexto da emergência. A enterotomografia computadorizada e a enterorressonância magnética são úteis para diagnóstico, seguimento, avaliação de complicações e para prognóstico. Avaliam as alças intestinais delgadas e os achados mesentéricos associados, além dos demais órgãos abdominais. Detectam sinais de atividade de doença, sinais de cronicidade e doença penetrante e complicações, importantes para a escolha do melhor tratamento. A interpretação dessas alterações é fundamental para que a equipe multidisciplinar trabalhe conjuntamente com compreensão da linguagem utilizada nos relatórios. Neste artigo, apresentamos uma revisão dos achados de imagem da doença de Crohn e ilustramos os possíveis achados dessa doença utilizando a nomenclatura padronizada proposta no consenso multidisciplinar composto pelas Sociedade de Radiologia Abdominal, Sociedade de Radiologia Pediátrica e a Associação Americana de Gastroenterologia, com recomendações de descrição, interpretação dos achados e recomendações de impressão.

Histogram analysis in the differentiation between adrenal adenomas and pheochromocytomas: the value of a single measurement / Análise por histograma para diferenciação entre adenomas da adrenal e feocromocitomas: o valor de uma medida única

Abstract Objective: To assess the diagnostic accuracy of histogram analysis on unenhanced computed tomography (CT) for differentiating between adrenal adenomas and pheochromocytomas (PCCs). Materials and Methods: We retrospectively identified patients with proven PCCs who had undergone CT examinations between January 2009 and July 2019 at one of two institutions. For each PCC, we selected one or two adenomas diagnosed within two weeks of the date of diagnosis of the PCC. For each lesion, two readers scored the size, determined the mean attenuation, and generated a voxel histogram. The 10th percentile (P10) was obtained from the conventional histogram analysis, as well as being calculated with the following formula: P10 = mean attenuation - (1.282 × standard deviation). The mean attenuation threshold, histogram analysis (observed) P10, and calculated P10 (calcP10) were compared in terms of their diagnostic accuracy. Results: We included 52 adenomas and 29 PCCs. The sensitivity, specificity, and accuracy of the mean attenuation threshold were 75.0%, 100.0%, and 82.5%, respectively, for reader 1, whereas they were 71.5%, 100.0%, and 81.5%, respectively, for reader 2. The sensitivity, specificity, and accuracy of the observed P10 and calcP10 were equal for both readers: 90.4%, 96.5%, and 92.6%, respectively, for reader 1; and 92.3%, 93.1%, and 92.6%, respectively, for reader 2. The increase in sensitivity was significant for both readers (p = 0.009 and p = 0.005, respectively). Conclusion: For differentiating between adenomas and PCCs, the histogram analysis (observed P10 and calcP10) appears to outperform the mean attenuation threshold as a diagnostic criterion.

Resumo Objetivo: Avaliar a acurácia diagnóstica da análise por histograma na tomografia computadorizada (TC) sem contraste para a diferenciação entre adenomas adrenais e feocromocitomas (FCCs). Materiais e Métodos: Identificamos, retrospectivamente, pacientes com diagnóstico de FCC confirmado que foram submetidos a exames de TC entre janeiro de 2009 e julho de 2019 em duas instituições distintas. Para cada FCC, selecionamos um ou dois adenomas diagnosticados em até duas semanas da data do diagnóstico do FCC. Para cada lesão, dois leitores pontuaram o tamanho, determinaram a atenuação média e geraram um histograma com os voxels das imagens. O percentil 10 (P10) foi obtido a partir da análise convencional do histograma, além de ser calculado com a seguinte fórmula: P10 = atenuação média - (1,282 × desvio-padrão). O limiar de atenuação média, o P10 da análise por histograma (P10 observado) e o P10 calculado (P10calc) foram comparados em termos de acurácia diagnóstica. Resultados: Foram incluídos 52 adenomas e 29 FCCs. A sensibilidade, especificidade e acurácia do limiar de atenuação média foram de 75,0%, 100,0% e 82,5% para o leitor 1, respectivamente, e de 71,5%, 100,0% e 81,5% para o leitor 2, respectivamente. A sensibilidade, especificidade e acurácia do P10 observado e do P10calc foram idênticas para os dois leitores: 90,4%, 96,5% e 92,6%, respectivamente, para o leitor 1; e 92,3%, 93,1% e 92,6%, respectivamente, para o leitor 2. O aumento da sensibilidade foi significativo para ambos os leitores (p = 0,009 e p = 0,005, respectivamente). Conclusão: Para a diferenciação entre adenomas e FCCs, a análise por histograma (P10 observado ou P10calc) parece superar o limiar de atenuação média como critério diagnóstico.

Tumor miofibroblastico inflamatorio que causa obstrucción intestinal en adulto mayor por intususcepción intestinal: Reporte de caso

La intususcepción intestinal en pacientes adultos es una entidad infrecuente, la cual corresponde alrededor del 5% de todas las causas de obstrucción intestinal. Su diagnóstico no es fácil, dado lo poco especifico de los síntomas de los pacientes que la presentan; este se sustenta principalmente en los hallazgos de los estudios de imagen. El manejo quirúrgico es la piedra angular del tratamiento de esta patología, y su éxito va a estar determinado por el diagnóstico oportuno y la experticia del cirujano tratante. En este artículo se presenta el caso de un paciente masculino de 62 años, que consulta por cuadro de dolor abdominal inespecífico y síntomas urinarios irritativos, el cual por persistencia del dolor abdominal pese al manejo medico es llevado a cirugía, donde se diagnostica de manera intraoperatoria una invaginación intestinal a nivel de íleon distal.

Intestinal intussusception in adult patients is a rare entity, which corresponds to about 5% of all causes of intestinal obstruction, its diagnosis is not easy given the lack of specific symptoms of patients who present it. This is mainly based on the findings of imaging studies, surgical management is the cornerstone of treatment of this pathology and its success will be determined by timely diagnosis as well as by the expertise of the treating surgeon. This article presents the case of a 62-year-old male patient who consults due to nonspecific abdominal pain and irritative urinary symptoms, who due to persistence of abdominal pain despite medical management is taken to surgery where it is diagnosed intraoperatively. an intestinal intussusception at the level of the distal ileum.

Correlation between chest computed tomography findings and pulmonary function test results in the post-recovery phase of COVID-19

ABSTRACT Objective The radiological and functional lung sequelae in COVID-19 survivors remain unclear. We compared the chest computed tomography findings of COVID-19 patients with normal and abnormal pulmonary function test results in the post-recovery phase. Methods The data of consecutive patients who underwent pulmonary function tests and chest computed tomography within 14 days after recovery from COVID-19 at two medical centers between May and October 2020 were collected retrospectively. Two thoracic radiologists who were blinded to the clinical information and pulmonary function test results classified the patients according to the computed tomography features, evidence of fibrotic-like changes, and semi-quantitative quantification of the extent of pulmonary abnormalities. The clinical characteristics and computed tomography findings of patients with normal pulmonary function test results were compared with those of patients with abnormal results. Results A total of 101 COVID-19 survivors, comprising 48 ambulatory and 53 hospitalized patients, were included at a median of 95 days from initial symptom onset. Computed tomography revealed fibrotic-like changes in 10.9% of patients. A reduction in the diffusion capacity of carbon monoxide was the most common lung function abnormality (19.8%). Abnormal diffusion capacity of carbon monoxide was associated with the presence and extension of lung opacities on chest computed tomography scans and fibrotic pulmonary abnormalities. The sensitivity, specificity, and accuracy of reduced diffusion capacity of carbon monoxide for detecting fibrotic-like pulmonary changes on chest computed tomography scans were 72.7%, 87.8%, and 86.1%, respectively. Conclusion Our study suggests that the presence of an abnormal diffusion capacity of carbon monoxide in the post-recovery phase of COVID-19 is associated with a greater risk of long-term parenchymal lung disease, as evidenced by the presence of fibrotic-like changes on chest computed tomography scans, such as traction bronchiectasis and architectural distortion.

Risk of pulmonary aspiration during semaglutide use and anesthesia in a fasting patient: a case report with tomographic evidence

ABSTRACT Pulmonary aspiration of gastric residues during anesthesia is a potentially fatal complication for which no specific treatment is available. The primary way to prevent its occurrence in the context of elective surgeries is adherence to fasting protocols. However, some clinical conditions can prolong the gastric emptying time, and the risk of aspiration may exist despite adequate fasting. Recognizing the risk factors for gastroparesis allows the adoption of preventive methods and is the primary way to reduce morbidity and mortality from pulmonary aspiration. In this scenario, the anesthesiologist can investigate the gastric content by using ultrasound, adjust the anesthetic technique, and even postpone elective surgeries. Here, we describe incidental computed tomography finding of solid contents in the stomach of a patient without prior identification of the risk factors for gastroparesis. The patient underwent elective renal nodule ablation under general anesthesia after fasting for 9 hours. During the procedure, solid contents in the stomach were noted on computed tomography. Subsequently, it was discovered that the patient had been using semaglutide for 6 days and had not disclosed this information. Semaglutide use may represent a new and significant risk factor for anesthesia-related pulmonary aspiration. Until studies provide information on the appropriate perioperative management of patients using semaglutide, anesthesiologists need to adopt preventive measures to avoid aspiration. Awareness of this potential association and open communication among patients, physicians, and anesthesia teams are essential for enhancing patient safety.

Detection of subsolid nodules on chest CT scans during the COVID-19 pandemic / Detecção de nódulos subsólidos na TC de tórax durante a pandemia de COVID-19

ABSTRACT Objective: To investigate the detection of subsolid nodules (SSNs) on chest CT scans of outpatients before and during the COVID-19 pandemic, as well as to correlate the imaging findings with epidemiological data. We hypothesized that (pre)malignant nonsolid nodules were underdiagnosed during the COVID-19 pandemic because of an overlap of imaging findings between SSNs and COVID-19 pneumonia. Methods: This was a retrospective study including all chest CT scans performed in adult outpatients (> 18 years of age) in September of 2019 (i.e., before the COVID-19 pandemic) and in September of 2020 (i.e., during the COVID-19 pandemic). The images were reviewed by a thoracic radiologist, and epidemiological data were collected from patient-filled questionnaires and clinical referrals. Regression models were used in order to control for confounding factors. Results: A total of 650 and 760 chest CT scans were reviewed for the 2019 and 2020 samples, respectively. SSNs were found in 10.6% of the patients in the 2019 sample and in 7.9% of those in the 2020 sample (p = 0.10). Multiple SSNs were found in 23 and 11 of the patients in the 2019 and 2020 samples, respectively. Women constituted the majority of the study population. The mean age was 62.8 ± 14.8 years in the 2019 sample and 59.5 ± 15.1 years in the 2020 sample (p < 0.01). COVID-19 accounted for 24% of all referrals for CT examination in 2020. Conclusions: Fewer SSNs were detected on chest CT scans of outpatients during the COVID-19 pandemic than before the pandemic, although the difference was not significant. In addition to COVID-19, the major difference between the 2019 and 2020 samples was the younger age in the 2020 sample. We can assume that fewer SSNs will be detected in a population with a higher proportion of COVID-19 suspicion or diagnosis.

RESUMO Objetivo: Investigar a detecção de nódulos subsólidos na TC de tórax de pacientes ambulatoriais antes e durante a pandemia de COVID-19, bem como correlacionar os achados de imagem com dados epidemiológicos. Nossa hipótese foi a de que nódulos não sólidos (pré) malignos foram subdiagnosticados durante a pandemia de COVID-19 em virtude da sobreposição de achados de imagem de nódulos subsólidos e pneumonia por COVID-19. Métodos: Estudo retrospectivo no qual foram incluídas todas as imagens de TC de tórax realizadas em pacientes ambulatoriais adultos (com idade > 18 anos) em setembro de 2019 (antes da pandemia de COVID-19) e em setembro de 2020 (durante a pandemia de COVID-19). As imagens foram reavaliadas por um radiologista torácico, e os dados epidemiológicos foram extraídos de questionários preenchidos pelos pacientes e de encaminhamentos clínicos. Modelos de regressão foram usados para controlar fatores de confusão. Resultados: Foram reavaliadas 650 e 760 imagens de TC de tórax nas amostras de 2019 e 2020, respectivamente. Foram encontrados nódulos subsólidos em 10,6% dos pacientes que compuseram a amostra de 2019 e em 7,9% daqueles que compuseram a amostra de 2020 (p = 0,10). Nódulos subsólidos múltiplos foram encontrados em 23 e 11 dos pacientes que compuseram as amostras de 2019 e 2020, respectivamente. As mulheres constituíram a maioria da população do estudo. A média de idade foi de 62,8 ± 14,8 anos na amostra de 2019 e de 59,5 ± 15,1 anos na amostra de 2020 (p < 0,01). A COVID-19 foi responsável por 24% de todos os encaminhamentos para a realização de TC em 2020. Conclusões: Foram detectados menos nódulos subsólidos na TC de tórax de pacientes ambulatoriais durante a pandemia de COVID-19 do que antes da pandemia, embora a diferença não tenha sido significativa. Além da COVID-19, a principal diferença entre as amostras de 2019 e 2020 foi o fato de que a amostra de 2020 era mais jovem. Podemos supor que menos nódulos subsólidos serão detectados numa população com maior proporção de suspeita ou diagnóstico de COVID-19.

Evaluation of Screws Positioning in Latarjet Surgery: Is There a Correlation between Parallelism to Glenoid and Radiographic Complications? / Avaliação do posicionamento dos parafusos na cirurgia de Latarjet: Existe correlação entre paralelismo à glenoide e complicações radiográficas?

Abstract Objective To evaluate whether the parallelism of screws with glenoid in Latarjet surgery interferes in the positioning of the graft and to verify the reproducibility of a method of measuring screws positioning. Methods Retrospective, multicenter study, of patients with anterior shoulder instability submitted to modified Latarjet surgery and at least one year of postoperative follow-up. Two radiologists analyzed the postoperative tomographic images, acquired in a database, to evaluate the positioning of screws and radiographic complications. Results We evaluated 34 patients, aged between 21 and 60 years, one of them with bilateral shoulder involvement, totaling 35 shoulders evaluated. The tomographic evaluation of the inclination angles of the screws showed no difference between the observers. There was intra- and interobserver agreement to evaluate the following surgical parameters: graft position, presence or not of radiographic complications. Conclusion The technique described for measuring the parallelism of screws in Latarjet surgery presented a very good and excellent intra-observer agreement, respectively. Screw parallelism with glenoid is recommended; however, it is not a mandatory and unique condition to avoid radiographic complications.

Resumo Objetivo Avaliar se o paralelismo dos parafusos com a glenoide na cirurgia de Latarjet interfere no posicionamento do enxerto e verificar a reprodutibilidade de um método de mensuração da posição dos parafusos. Métodos Estudo retrospectivo, multicêntrico, de pacientes com instabilidade anterior do ombro submetidos à cirurgia de Latarjet modificada e no mínimo 1 ano de seguimento pós-operatório. Dois médicos radiologistas analisaram as imagens tomográficas pós-operatórias, adquiridas em um banco de dados, para avaliação do posicionamento dos parafusos e das complicações radiográficas. Resultados Foram avaliados 34 pacientes, com idades entre 21 e 60 anos, sendo que um deles tinha acometimento bilateral dos ombros, totalizando 35 ombros avaliados. A avaliação tomográfica dos ângulos de inclinação dos parafusos não apresentou diferença entre os observadores. Houve concordância intra e interobservador para avaliação dos seguintes parâmetros cirúrgicos: posição do enxerto, presença ou não de complicações radiográficas. Conclusão A técnica descrita para mensuração do paralelismo dos parafusos na cirurgia de Latarjet apresentou uma concordância intra e inter observador muito boa e excelente, respectivamente. O paralelismo do parafuso com a glenoide é recomendado; no entanto, não é condição obrigatória e única para se evitar as complicações radiográficas.

Application value of deep learning reconstruction algorithm in CT imaging of abdominal phantoms / 中华放射医学与防护杂志

Objective:To explore the value of the deep learning image reconstruction (DLIR) algorithm in improving the CT image quality of abdominal phantoms under different radiation doses by comparing the DLIR algorithm with the conventional Adaptive Statistical Iterative Reconstruction-V (ASIR-V) technique.Methods:Two groups with tube voltages of 100 kV and 120 kV (also referred to as the 100 kV and 120 kV groups, respectively) were involved. Each group was further divided into six subgroups based on different volumetric CT dose indices (CTDI vol: 2, 4, 6, 8, 10 and 15 mGy). Subsequently, CT images based on the filtered back projection (FBP) algorithm were obtained and were then reconstructed using the ASIR-V algorithm with different weights (ASIR-V 50%, 80%, and 100%) and the DLIR algorithm with different levels (DLIR-L, M, and -H). As a result, 84 groups of images were obtained in total. Afterward, this study compared and analyzed the variations in CT values, noise, signal-to-noise ratios (SNRs), contrast-to-noise ratios (CNRs), and subjective scores of various parts in various CTDI vol subgroups under different reconstruction conditions. In addition, the subjective scores of the image quality were compared using the Kruskal-Wallis H test, while objective indices and radiation doses were compared through the univariate analysis of variance (ANOVA) and the paired t test. Results:Under the same tube voltage, there were statistically significant differences in the noise, SNRs, and CNRs of various parts in various CTDI vol subgroups under different reconstruction conditions ( F = 415.39, 315.30, P < 0.001), while there was no statistically significant difference in the noise, SNRs, and CNRs of images constructed using ASIR-V 50% and DLIR-L ( P > 0.05). Under different tube voltages, the subjective scores of both groups show statistically significant differences (100 kV group: H = 13.47, P = 0.036; 120 kV group: H = 12.99, P = 0.043). Moreover, two physicians offered consistent subjective scores, with Kappa values > 0.70. Among these images, DLIR-H images showed the highest subjective scores, followed by DLIR-M and ASIR-V 50% images, which had roughly consistent subjective scores. Moreover, the subjective scores of the 100 kV group were slightly higher than those of the 120 kV group. With the ASIR-V 50% images of the subgroup with a CTDI vol of 15 mGy as references, the DLIR-L, -M, and -H reduced radiation doses by more than 30%, 70% and 85%, respectively on the premise that diagnostic requirements were met. Conclusions:The DLIR algorithm can not only significantly reduce the image noise and improve the image quality, but also effectively decrease the radiation doses on the premise of meeting the diagnostic requirements. It is recommended that 100 kV tube voltage combined with a medium- or high-level DLIR algorithm should be applied to low-dose abdominal CT scans in clinical applications.

A nomogram based on CT enterography signs for prediction of intestinal penetrating lesions in patients with Crohn disease / 中华放射学杂志

Objective:To explore the value of a nomogram model based on the CT enterography (CTE) signs for prediction of intestinal penetrating lesions in patients with Crohn disease (CD).Methods:The clinical and CTE data of CD patients who underwent at least two CTE examinations from January 2010 to June 2020 in the First Affiliated Hospital of Sun Yat-sen University were retrospectively collected. A total of 112 patients were enrolled, and according to whether there was intestinal wall penetration in the last CTE observation were divided into non-penetration group (84 cases) and penetration group (28 cases). First, the clinical and CTE data for the first examination was analyzed by using univariate and multivariate Cox proportional hazards regression to screen out high-risk factors that could effectively predict intestinal wall penetrating lesions in CD patients and established a nomogram model. Then the change trend of CTE data (ΔCTE) between the first and last clinical and CTE signs was analyzed by using univariate and multivariate Cox proportional hazards regression, and built a nomogram model to sort out ΔCTE that may accompany the development of penetrating lesions in CD patients. The Harrell concordance index was used to evaluate the discriminative ability of the nomogram model.Results:In the first time clinical and CTE signs, multivariate Cox proportional hazards regression results showed that numbers of diseased bowel segments (HR=0.686, 95%CI 0.475-0.991, P=0.045) and the shortest diameter of the largest lymph node (HR=0.751, 95%CI 0.593-0.949, P=0.017) were independent protection factors for penetrating lesions, and rough bowel wall surface (HR=5.626, 95%CI 2.466-12.839, P<0.001) was an independent risk factor for penetrating lesions. The specificity and sensitivity of the nomogram model to predict non-penetration lesions were 82.1% and 59.5% respectively, and the Harrell concordance index was 0.810 (95%CI 0.732-0.888). In the ΔCTE signs, multivariate Cox proportional hazards regression showed that Δrough bowel wall surface (always rough bowel wall surface HR=12.344, 95%CI 2.042-74.625, P=0.006; slide bowel wall surface becomes rough bowel wall surface HR=28.720, 95%CI 4.580-180.112, P<0.001) and Δthe shortest diameter of the largest lymph node (HR=1.534, 95%CI 1.091-2.157, P=0.014) were independent risk factors for penetrating lesions. The specificity and sensitivity of the nomogram model were 89.3% and 79.2% respectively, and the Harrell concordance index was 0.876 (95%CI 0.818-0.934). Conclusion:The nomogram based on CTE signs of numbers of diseased bowel segments, the shortest diameter of the largest lymph node and rough bowel wall surface and ΔCTE can effectively predict the intestinal wall penetrating lesions of CD patients.

The comparison of anatomical and functional features between patients with ischemic with non-obstructive coronary artery disease and obstructive coronary artery disease by CT / 中华放射学杂志

Objective:To explore the difference of the vessel and plaque characteristics, myocardial perfusion and cardiac function between patients with ischemia with non-obstructive coronary artery disease (INOCA) and obstructive coronary artery disease (CAD).Methods:From July 2021 to June 2022, 101 patients with angina were referred to dynamic computed tomography myocardial perfusion (CTP) and coronary computed tomography angiography (CCTA) and retrospectively included in our hospital. Based on the results of CTP and CCTA, patients were divided into INOCA (27 cases), moderate obstructive CAD (26 cases) and severe obstructive CAD (48 cases). The anatomical coronary artery stenosis, plaque characteristics and myocardial perfusion features of all patients were analyzed. Furthermore, left ventricular global longitudinal strain (GLS), global circumferential strain (GCS), and global radial strain (GRS) were obtained on full-phase reconstruction CCTA image by using Medis Suite 3.2 postprocessing software. Multigroup analysis used one way ANOVA or Kruskal Wallis H test. Results:Patients with INOCA were younger than patients with moderate and severe obstructive CAD ( P<0.001). INOCA patients (7.4%, 2/27) had lower rate of positive remodeling than both moderate (57.7%, 15/26, P<0.001) and severe obstructive CAD patients (33.3%, 16/48, P=0.017). The percentage of ischemic myocardium volume in patients with INOCA were similar with those in patients with severe CAD (all P>0.05), but significantly higher than those in patients with moderate CAD (all P<0.05). No significant difference in terms of GLS was detected between patients with INOCA [-17.4% (-21.6%, -11.6%)] and severe CAD [-17.6% (-21.9%, -14.8%), P=0.536], however, patients both with INOCA and severe CAD also had higher GLS than patients with moderate obstructive CAD [-22.3% (-29.8%, -19.0%), all P<0.05]. Conclusions:Based on"one-stop-shop"CTP combined with CCTA imaging, early cardiac functional changes including abnormal myocardial perfusion and myocardial strain in INOCA patients were similar to those in patients with severe obstructive CAD and more severe than those in patients with moderate obstructive CAD.

Optimizing the risk stratification of coronary CT angiography for non-obstructive coronary artery disease based on cluster analysis / 中华放射学杂志

Objective:To explore the risk stratification value of coronary CT angiography (CCTA) in patients with non-obstructive coronary artery disease based on cluster analysis and to identify the high-risk population of cardiovascular adverse events in patients.Methods:Prospective consecutive patients with suspected coronary artery disease who underwent CCTA examination and were confirmed as non-obstructive coronary heart disease were enrolled in the General Hospital of Chinese PLA from January 1, 2015 to December 31, 2017. The clinical characteristics and CCTA diagnosis information of patients were collected, and then follow-up was performed to obtain adverse cardiovascular events. Firstly, the cluster analysis based on CCTA information divided the patients into different groups. Then, the risk of adverse cardiovascular events was compared between different groups. Finally, segment involvement score (SIS) score, Leiden score, SIS score combined with clinical characteristics, Leiden score combined with clinical characteristics, and cluster information combined with clinical characteristics were used to stratify the population, and the concordance index-time curve and net reclassification improvement (NRI) index were described to compare the risk stratification ability of the five different models.Results:A total of 3 402 patients with non-obstructive coronary artery disease were included in the study, of whom 104 had adverse cardiovascular events during the follow-up period. Cluster analysis based on CCTA information classified patients into 3 different groups. There were statistically significant differences in clinical characteristics, CCTA information, and survival outcomes between groups ( P<0.05). The results of the concordance index-time curve showed that the risk stratification ability of CCTA cluster information combined with clinical characteristics was better than the current SIS score, Leiden score, SIS score combined with clinical characteristics, Leiden score combined with clinical characteristics. At the 1-year and 2-year time cutoffs, cluster information combined with clinical characteristics showed a positive increase in INR compared with the first four models (INR was 0.248 and 0.293, 0.316 and 0.293, 0.147 and 0.003, 0.192 and 0.007, respectively). Conclusion:CCTA based on cluster analysis has a good risk stratification value for patients with non-obstructive coronary artery disease and is helpful for individualized intervention.

Relationship between abnormal imaging findings of adipose tissue around primary colon cancer and prognosis / 中华放射学杂志

Objective:To explore the relationship between the abnormal adipose tissue around the primary tumor of colon cancer and the prognosis.Methods:From January 2015 to December 2017, 448 patients with colon cancer in Peking University Cancer Hospital were retrospectively and consecutively collected. The scores were assigned to the severity, horizontal and vertical ranges of peritumoral adipose tissue (PAT) abnormalities, and the cumulative scores were calculated to establish the PAT grades from 1 to 3. We defined a score of 0 or 1 as PAT grade 1, a score of 2 as PAT grade 2, a score of 3 as PAT grade 3. The patients were followed up, and the overall survival (OS) and metastasis-free survival (MFS) were recorded. The Kaplan-Meier curve, log-rank test and Cox regression analysis were used to evaluate its impact on prognosis, and the hazard ratio (HR) and 95% confidence interval (CI) were calculated.Results:Among the 448 patients, patients with PAT grade 1, 2, and 3 accounted for 70.1% (314/448), 18.1% (81/448), and 11.8% (53/448), respectively. The Kaplan-Meier survival curve showed that patients with PAT grade 1 had the best OS, patients with grade 3 had the worst OS, and patients with grade 2 were in between, and the difference was statistically significant (χ 2=27.38, P<0.001). There were statistically significant differences between the grades in pairs ( P<0.05). There was no significant difference in MFS between different PAT grades (χ 2=2.85, P=0.240). The results of Cox regression analysis showed that PAT grade was an independent factor affecting the OS. Compared with PAT grade 1, the risk of death in patients with PAT grade 2 and 3 was significantly increased (HR 2.563, 95%CI 1.181-5.561; HR 2.269, 95%CI 1.005-5.121; P=0.034). PAT grade was not an independent factor of MFS ( P=0.253). Conclusion:The PAT grade established based on the degree and scope of abnormal PAT in colon cancer is an independent factor for poor prognosis of colon cancer.

Construction of a prediction model for lung cancer combined with chronic obstructive pulmonary disease by combining CT imaging features with clinical features and evaluation of its efficacy / 中华放射学杂志

Objective:To assess the effectiveness of a model created using clinical features and preoperative chest CT imaging features in predicting the chronic obstructive pulmonary disease (COPD) among patients diagnosed with lung cancer.Methods:A retrospective analysis was conducted on clinical (age, gender, smoking history, smoking index, etc.) and imaging (lesion size, location, density, lobulation sign, etc.) data from 444 lung cancer patients confirmed by pathology at the Second Affiliated Hospital of Naval Medical University between June 2014 and March 2021. These patients were randomly divided into a training set (310 patients) and an internal test set (134 patients) using a 7∶3 ratio through the random function in Python. Based on the results of pulmonary function tests, the patients were further categorized into two groups: lung cancer combined with COPD and lung cancer non-COPD. Initially, univariate analysis was performed to identify statistically significant differences in clinical characteristics between the two groups. The variables showing significance were then included in the logistic regression analysis to determine the independent factors predicting lung cancer combined with COPD, thereby constructing the clinical model. The image features underwent a filtering process using the minimum absolute value convergence and selection operator. The reliability of these features was assessed through leave-P groups-out cross-validation repeated five times. Subsequently, a radiological model was developed. Finally, a combined model was established by combining the radiological signature with the clinical features. Receiver operating characteristic (ROC) curves and decision curve analysis (DCA) curves were plotted to evaluate the predictive capability and clinical applicability of the model. The area under the curve (AUC) for each model in predicting lung cancer combined with COPD was compared using the DeLong test.Results:In the training set, there were 182 cases in the lung cancer combined with COPD group and 128 cases in the lung cancer non-COPD group. The combined model demonstrated an AUC of 0.89 for predicting lung cancer combined with COPD, while the clinical model achieved an AUC of 0.82 and the radiological model had an AUC of 0.85. In the test set, there were 78 cases in the lung cancer combined with COPD group and 56 cases in the lung cancer non-COPD group. The combined model yielded an AUC of 0.85 for predicting lung cancer combined with COPD, compared to 0.77 for the clinical model and 0.83 for the radiological model. The difference in AUC between the radiological model and the clinical model was not statistically significant ( Z=1.40, P=0.163). However, there were statistically significant differences in the AUC values between the combined model and the clinical model ( Z=-4.01, P=0.010), as well as between the combined model and the radiological model ( Z=-2.57, P<0.001). DCA showed the maximum net benifit of the combined model. Conclusion:The developed synthetic diagnostic combined model, incorporating both radiological signature and clinical features, demonstrates the ability to predict COPD in patients with lung cancer.

The clinical and imaging presentations of the stapical footplate hernia related to inner ear malformation / 中华放射学杂志

Objective:To summarize the clinical and imaging presentations of stapical footplate hernia related to inner ear malformation (SFH-Re-IEM).Methods:The clinical and imaging data of 19 patients (24 ears) with SFH-Re-IEM from Shandong Provincial ENT Hospital between June 2014 to June 2022 were retrospectively analyzed. The clinical presentations and headache and the high resolution CT (HRCT) and MRI findings including associated inner ear malformation (IEM) type, internal auditory canal (IAC) malformation, bony defect of the stapical footplate, the extent, margin, density and signal of the herniation cysts, the density and signal of ipsilateral intratympanic, cochlear osseous labyrinthitis were recorded.Results:Among 19 SFH-Re-IEM patients, including 14 males and 5 females, 3 (1, 12) years old. All of the affected ears presented sensorineural or mixed hearing loss, 1 ear for moderate, 7 ears for severe and 16 ears for extremely severe. Besides this, the vertigo in 1 case, otalgia and ear fullness in 2 cases were found, and the others were detected accidentally. Among 24 ears with SFH-Re-IEM, 9 ears (37.5%) consisting with incomplete partition type Ⅰ, 3 ears (12.5%) with common cavity, 7 ears (29.2%) with cochlear aplasia, 3 ears (12.5%) with cochlear dysplasia type Ⅱ, and 2 ears (8.3%) with Mondini deformity were found respectively. Four ears (16.7%) were associated with IAC enlargement and the bony defect of IAC fundus, 19 ears (79.2%) were accompanied with dysplasia in the IAC fundus. In all the 24 ears with SFH-Re-IEM, the focal bony defect of the affected stapical footplate and the hemispherical soft-tissue-density herniating cysts protruding into the tympanium were presented on HRCT, and the herniating cysts presenting the cerebrospinal fluid-like signal with the well-defined margin and the ipsilateral normal tympanium were shown on the MRI hydrographic sequence. Two ears underwent the perilymphaticum gadolinium based on MRI, which demonstrated the hypersignal gadolinium in the perilymphatic space entered into the herniating cysts. Two ears were accompanied with the cochlear osseous labyrinthitis.Conclusion:The ears with IEM-Re-SFH usually present the serious hearing loss. The ipsilateral severe IEM, focal bony defect of the stapical footplate and perilymph herniating are characteristic imaging appearances.

Predicting the invasiveness of lung adenocarcinoma manifesting as ground-glass opacity using spectral CT multi-parameter functional imaging / 中华放射学杂志

Objective:To explore the clinical value of quantitative parameters on spectral CT in predicting the invasiveness of lung adenocarcinoma manifesting as ground-glass nodules (GGN).Methods:The clinical and imaging data of 129 patients with pathologically confirmed lung adenocarcinoma who were surgically resected in the First Affiliated Hospital of Zhengzhou University from March to October 2022 were retrospectively analyzed, including 45 males and 84 females, aged from 33 to 81. According to the pathological results, they were divided into the minimally invasive adenocarcinoma (MIA) group ( n=64) and the invasive adenocarcinoma (IAC) group ( n=65). All patients underwent enhanced spectral CT within two weeks before surgery. The iodine density map, Z-Effective (Z eff) map, and electron density (ED) map were reconstructed on the post-processing workstation, and the spectral parameters, including normalized iodine concentration (NIC), arterial enhancement fraction (AEF), Z eff, and ED were measured and calculated. Conventional CT features were analyzed, including maximum diameter, CT value, nodule types, margin, lobulation sign, spiculation sign, bubble sign, pleural retraction sign, abnormal vascular sign, and air bronchial sign. The clinical features, conventional CT characteristics and spectral CT parameters of two groups were compared using the independent sample t test, the Mann-Whitney U test, and the χ 2 test. Multivariate logistic regression analysis was used to evaluate the independent risk factors of lung adenocarcinoma invasiveness, and the model was constructed. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the performance of parameters and models in predicting the invasiveness of lung adenocarcinoma. Results:There were significant differences between the MIA group and IAC group in maximum diameter, CT value, nodule type, margin, spiculation sign, pleural retraction sign, air bronchial sign, venous phase NIC, AEF, venous phase Z eff, arterial phase ED, venous phase ED ( P<0.05). Multivariate logistic regression analysis showed that the maximum diameter (OR=1.183, 95%CI 1.062-1.318), CT value (OR=1.004, 95%CI 1.001-1.007), venous phase NIC (OR=1.185, 95%CI 1.083-1.298), AEF(OR=0.975, 95%CI 0.957-0.994), venous phase Z eff (OR=0.031, 95%CI 0.005-0.196) were independent influence factors for the invasiveness of lung adenocarcinoma. The conventional CT model was established with the maximum diameter and CT value, and the spectral CT model was established with venous phase NIC, AEF, and venous phase Z eff. The combined model was established with all the parameters above. Areas under the ROC curve of the conventional CT model, the spectral CT model, and the combined model for predicting the invasiveness of lung adenocarcinoma were 0.828, 0.854, and 0.902, respectively. Conclusion:The quantitative parameters of double-layer detector spectral CT can be used as an indicator to predict the invasiveness of lung adenocarcinoma manifesting as GGN, and AEF has the highest diagnostic efficacy. Spectral CT combined with conventional CT features can further improve the diagnostic efficiency.