New infusion device for use in acquisition of images during endovascular procedures: an experimental model / Novo dispositivo de infusão para a aquisição de imagens durante procedimentos endovasculares: modelo experimental

Abstract Background The contrast power injector (CPI) is the gold standard method for injecting contrast with the pressure and flow needed to generate a satisfactory images during endovascular procedures, but it is an expensive tool, narrowing its wide-scale applications. One alternative is the manual injection (MI) method, but this does not generate the pressure required for adequate visualization of anatomy. It is therefore imperative to create an alternative low-cost method that is capable of producing high quality images. Objectives To compare the injection parameters of a new mechanical device (Hand-Crank) created in a university hospital with the MI method and with the contrast power injector's ideal values. Methods A circulation phantom was constructed to simulate the pressure in the aorto-iliac territory and the injection parameters of the two methods were compared in a laboratory setting. Student's t test and the Mann-Whitney test were used for statistical analysis. Three vascular surgery residents (the authors) performed the injections (each performed 9 tests using conventional manual injection and 9 tests using the Hand-Crank, totaling 54 injections). Results There were statistical differences between the two methods (p<0.05) in total volume injected until maximum pressure was attained, pressure variation, maximum pressure, total injection time, and time to reach the maximum pressure. Conclusions The Hand-Crank can achieve higher maximum pressure, higher average flow, and lower injection time than the manual method. It is a simple, low-cost, and effective tool for enhancing injection parameters in an experimental setup. It could help to produce higher quality images in a clinical scenario.

Resumo Contexto A bomba injetora é o método padrão-ouro para a injeção de contraste em aortografias. Entretanto, é uma ferramenta de alto custo, o que limita o seu uso. A injeção manual surge como alternativa, mas a pressão gerada com esse método é baixa, e, por isso, a qualidade das imagens não é usualmente satisfatória. Assim, a criação de um método de baixo custo capaz de gerar imagens de qualidade é imperativo. Objetivos Comparar os parâmetros de injeção de um novo dispositivo mecânico (manivela articulada) criado em um hospital universitário com os parâmetros da injeção manual e com os valores ideais da bomba injetora. Métodos Um simulador do território aórtico foi construído, e parâmetros de injeção entre os diferentes métodos em um cenário laboratorial controlado foram analisados. O teste t de Student e o teste de Mann-Whitney foram usados para análise estatística. Três residentes de Cirurgia Vascular realizaram os testes (nove usando o novo dispositivo, e nove usando a injeção manual, totalizando 54 injeções). Resultados Houve diferença estatisticamente significativa (p < 0,05) entre os dois métodos, considerando os parâmetros: variação de pressão, pressão máxima, tempo de injeção, tempo até a pressão máxima e volume até a pressão máxima. Conclusões A manivela articulada atingiu níveis superiores de pressão e de velocidade de injeção, com menor tempo de injeção do que a injeção manual. É um dispositivo simples, de baixo custo e com resultados comparáveis à bomba injetora, o que sugere seu uso potencial na geração de imagens satisfatórias em aortografias.

Comparison of one-catheter strategy versus conventional two-catheter strategy on the volume of radiological contrast and diagnostic coronary catheterization performance by transradial access: A systematic review and meta-analysis of randomized clinical trials / Comparación de la estrategia de catéter único versus la estrategia convencional de dos catéteres sobre el volumen de contraste radiológico y el rendimiento del cateterismo coronario diagnóstico por acceso transradial: una revisión sistemática y meta-análisis de ensayos clínicos aleatorizados

Abstract Background: One-catheter strategy, based in multipurpose catheters, allows exploring both coronary arteries with a single catheter. This strategy could simplify coronary catheterization and reduce the volume of contrast administration, by reducing radial spasm. To date, observational studies showed greater benefits regarding contrast consumption and catheterization performance than controlled trials. The aim of this work is to perform the first systematic review and meta-analysis of randomized clinical trials (RCT) to adequately quantify the benefits of one-catheter strategy, with multipurpose catheters, over conventional two-catheter strategy on contrast consumption, and catheterization performance. Methods: A search in PubMed, CINALH, and CENTRAL databases was conducted to identify randomized trials comparing one-catheter and two-catheter strategies. The primary outcome was volume of iodinated contrast administrated. Secondary endpoints, evaluating coronary catheterization performance included: arterial spasm, fluoroscopy time, and procedural time. Results: Five RCT were included for the final analysis, with a total of 1599 patients (802 patients with one-catheter strategy and 797 patients with two-catheter strategy). One-catheter strategy required less administration of radiological contrast (difference in means [DiM] [95% confidence interval (CI)]; −3.831 mL [−6.165 mL to −1.496 mL], p = 0.001) as compared to two-catheter strategy. Furthermore, less radial spasm (odds ratio [95% CI], 0.484 [0.363 to 0.644], p < 0.001) and less procedural time (DiM [95% CI], −72.471 s [−99.694 s to −45.249 s], p < 0.001) were observed in one-catheter strategy. No differences on fluoroscopy time were observed. Conclusions: One-catheter strategy induces a minimal reduction on radiological contrast administration but improves coronary catheterization performance by reducing arterial spasm and procedural time as compared to conventional two-catheter strategy.

Resumen Antecedentes: La estrategia de catéter único permite explorar ambas coronarias con un solo catéter. Nuestro objetivo es realizar la primera revisión sistemática y meta-análisis de ensayos clínicos aleatorizados para cuantificar adecuadamente los beneficios de la estrategia de catéter único, con catéteres multipropósito, sobre la estrategia convencional de dos catéteres. Métodos: Se realizó una búsqueda en PubMed, CINALH y CENTRAL, identificando ensayos aleatorizados que compararan estrategias de un catéter y dos catéteres. El resultado primario fue volumen de contraste administrado. Los secundarios, que evaluaron el rendimiento del cateterismo, incluyeron: espasmo radial, tiempo de fluoroscopia y de procedimiento. Resultados: Se incluyeron cinco ensayos, totalizando 1,599 pacientes (802 con estrategia de un catéter y 797 con estrategia de dos catéteres). La estrategia de catéter único requirió menos contraste (diferencia-de-medias; −3.831 mL [−6.165 mL a −1.496 mL], p = 0.001), presentando menos espasmo radial (odds ratio, 0.484 [0.363 a 0.644], p < 0.001) y menos tiempo de procedimiento (diferencia-de-medias; −72.471 s [−99.694 s a −45.249 s], p < 0.001). No hubo diferencias en el tiempo de fluoroscopia. Conclusiones: La estrategia de catéter único induce una reducción mínima en la administración de contraste, pero mejora el rendimiento del cateterismo al reducir el espasmo radial y el tiempo de procedimiento en comparación con la estrategia convencional.

Utilidad del contraste endovenoso en ecoendoscopía pancreática. Reporte de casos / Usefulness of intravenous contrast in pancreatic echoendoscopy. A case series

RESUMEN El empleo del contraste endovenoso permite aumentar la capacidad diagnostica de la ecoendoscopía en muchas condiciones patológicas de forma no invasiva, mediante la evaluación de patrones de realce en tiempo real (hipo, iso e hipercaptación), permitiendo a su vez definir diagnósticos diferenciales o predecir diagnósticos histológicos con alta precisión por medio de la caracterización de la vascularidad o microvasculatura de un órgano o lesión. Sin embargo, su empleo en nuestro medio está limitado por no contar con estos medios de contraste. Reportamos tres casos de ecoendoscopía contrastada realizada en patología pancreática realizada en nuestro hospital, en el que se describe la utilidad en el diagnóstico y manejo de lesiones sólidas y quísticas del páncreas.

ABSTRACT The intravenous contrast (IV) allows for improving the diagnostic accuracy of echoendoscopy for many pathologic conditions. IV contrast provides a non-invasive method that through the use of real-time enhancement patterns (hypo, iso, and hypercaptation), a highly accurate histological diagnosis can be made by characterizing the microvasculature of an organ or a lesion. However, the lack of availability of IV contrast limited its use in our setting. We reported three cases of endoscopic ultrasound with IV contrast performed in the pancreatic department of National Hospital Eduardo Rebagliati Martins in Lima, Peru. We described the effectiveness of IV contrast in the diagnosis and the management of solid and cystic lesions in the pancreas.

An augmented patient-specific approach to administration of contrast agent for CT renal angiography

ABSTRACT Purpose This hybrid retrospective and prospective study performed on 200 consecutive patients undergoing renal CTA, investigates the opacification of renal vasculature, radiation dose, and reader confidence. Materials and Methods 100 patients were assigned retrospectively to protocol A and the other 100 were allocated prospectively to protocol B. Both protocols implemented a contrast material and saline flow rate of 4.5 mL/sec. Protocol A utilized a 100 mL of low-osmolar nonionic IV contrast material (Ioversol 350 mg I/mL) while protocol B employed a patient-tailored contrast media formula using iso-osmolar non-ionic (Iodixanol 320 mg I/mL). Results Arterial opacification in the abdominal aorta and in the bilateral main proximal renal arteries demonstrated no statistical significance (p>0.05). Only the main distal renal artery of the left kidney in protocol B was statistically significant (p<0.046). In the venous circulation, the IVC demonstrated a significant reduction in opacification in protocol B (59.39 HU ± 19.39) compared to A (87.74 HU ± 34.06) (p<0.001). Mean CNR for protocol A (22.68 HU ± 13.72) was significantly higher than that of protocol B (14.75 HU ± 5.76 p< 0.0001). Effective dose was significantly reduced in protocol B (2.46 ± 0.74 mSv) compared to A (3.07 ± 0.68 mSv) (p<0.001). Mean contrast media volume was reduced in protocol B (44.56 ± 14.32 mL) with lower iodine concentration. ROC analysis demonstrated significantly higher area under the ROC curve for protocol B (p< 0.0001), with inter-reader agreement increasing from moderate to excellent in renal arterial visualization. Conclusion Employing a patient-tailored contrast media injection protocol shows a significant refinement in the visualization of renal vasculature and reader confidence during renal CTA.

Improving acute demyelinating lesion detection: which T1-weighted magnetic resonance acquisition is more sensitive to gadolinium enhancement? / Aumento da detecção das placas desmielinizantes agudas: qual aquisição de ressonância magnética ponderada em T1 é a mais sensível em demonstrar impregnação pelo gadolínio?

ABSTRACT Because of the need for a standardized and accurate method for detecting multiple sclerosis (MS) inflammatory activity, different magnetic resonance (MR) acquisitions should be compared in order to choose the most sensitive sequence for clinical routine. Objective To compare the sensitivity of a T1-weighted image to a single dose of gadolinium (Gd) administration both with and without magnetization transfer to detect contrast enhancement in active demyelinating focal lesions. Methods A sample of relapsing-remitting MS patients were prospectively examined separately by two neuroradiologists using a 1.5 Tesla scanner. The outcome parameters were focused on Gd-enhancement detection attributed to acute demyelination. All MR examinations with at least one Gd-enhancing lesion were considered positive (MR+) and each lesion was analyzed according to its size and contrast ratio. Results Thirty-six MR examinations were analyzed with a high inter-observer agreement for MR+ detection (k coefficient > 0.8), which was excellent for the number of Gd-enhancing lesions (0.91 T1 spin-echo (SE), 0.88 T1 magnetization transfer contrast (MTC) sequence and 0.99 magnetization-prepared rapid acquisition with gradient-echo (MPRAGE). Significantly more MR+ were reported on the T1 MTC scans, followed by the T1 SE, and MPRAGE scans. Confidently, the T1 MTC sequence demonstrated higher accuracy in the detection of Gd-enhancing lesions, followed by the T1 SE and MPRAGE sequences. Further comparisons showed that there was a statistically significant increase in the contrast ratio and area of Gd-enhancement on the T1 MTC images when compared with both the SE and MPRAGE images. Conclusion Single-dose Gd T1 MTC sequence was confirmed to be the most sensitive acquisition for predicting inflammatory active lesions using a 1.5 T magnet in this sample of MS patients.

RESUMO No que se refere à necessidade de um método preciso e padronizado para a detecção de atividade inflamatória em esclerose múltipla (EM), diferentes aquisições de RM devem ser comparadas com objetivo de escolher a sequência mais sensível para a rotina clínica. Objetivo Comparar a sensibilidade das sequências ponderadas em T1 após a administração endovenosa de uma única dose de gadolínio, com e sem a adição da transferência de magnetização, para detectar a impregnação das lesões desmielinizantes focais agudas. Métodos Uma amostra de pacientes com EM-RR foi prospectivamente avaliada separadamente por dois neurorradiologistas em um equipamento de RM de 1,5 Tesla. Os parâmetros de desfecho foram direcionados para a avaliação da detecção de impregnação pelo Gd atribuída à desmielinização aguda. Todos os exames de RM que demonstraram ao menos uma lesão com impregnação pelo Gd foram considerados positivos (RM+) e cada lesão foi analisada de acordo com suas dimensões e contraste. Resultados Trinta e seis exames de RM foram analisados. Os avaliadores demonstraram elevada concordância para a detecção de RM+ (coeficiente> 0,8), sendo excelente quanto ao número de lesões com impregnação pelo Gd (0,91 SE, 0,88 T1 MTC e 0,99 MPRAGE). A sequência T1 MTC apresentou número significativamente maior de RM+, seguida pelas sequências T1 SE e MPRAGE. De forma análoga, a sequência T1 MTC demonstrou maior acurácia na detecção de lesões com impregnação pelo Gd, seguida pelas sequências T1 SE e MPRAGE. As demais comparações demonstraram aumento estatisticamente significativo na relação de contraste e na área de impregnação pelo Gd nas imagens T1 MTC quando comparadas às imagens SE e MPRAGE. Conclusão A sequência T1 MTC com uma única dose de Gd confirmou ser a sequência mais sensível em demonstrar lesões inflamatórias agudas em equipamento de 1,5 T nessa coorte de pacientes com EM.

Impacto de la angiografía coronaria rotacional en la cantidad total de contraste administrado y la exposición a las radiaciones ionizantes en pacientes en los que se realizan procedimientos coronarios invasivos: revisión sistemática y metaanálisis / Impact of rotational coronary angiography in the amount of iodinated contrast and the exposure to ionising radiations in patients undergoing invasive coronary procedures: A systematic review and meta-analysis

Resumen Antecedentes: Los procedimientos coronarios invasivos conllevan la administración de contraste y la exposición a radiaciones ionizantes, comportando un incremento de la morbimortalidad. La angiografía coronaria rotacional (ACR) permite adquirir múltiples proyecciones con una inyección de contraste. Hasta la fecha, no hay metaanálisis específicos comparando la ACR y la angiografía coronaria convencional (ACC) en pacientes en los que se realizan procedimientos coronarios invasivos, tanto diagnósticos como diagnósticos y terapéuticos. El objetivo de este metaanálisis es evaluar el impacto de la ACR en la cantidad de contraste, y la radiación ionizante en procedimientos coronarios invasivos. Métodos: Se realizó una búsqueda en las bases de datos PubMed y Ovid para identificar estudios tanto diagnósticos como diagnósticos y terapéuticos que comparasen ACR y ACC. Los estudios fueron evaluados sobre la calidad y los sesgos, y fueron incluidos si contemplaban alguna de las siguientes variables de valoración: volumen de contraste, radiación ionizante medida como producto dosis-área, Kerma-aire o tiempo de fluoroscopia. Resultados: Dieciséis estudios, totalizando 2,327 pacientes, fueron incluidos en el análisis final (1,146 pacientes recibieron ACR y 1,181, ACC), objetivándose diferencias significativas en volumen de contraste (diferencia estándar de medias (intervalo de confianza al 95%) −1.887 (−2.472 a −1.302); p < 0.001), producto dosis-área (−0.726 (−1.034 a −0.418); p < 0.001), Kerma-aire (−0.842 (−1.104 a −0.581); p < 0.001) y tiempo de fluoroscopia (0.263 (−0.496 a −0.030); p = 0.027). Conclusiones: La ACR permite reducir el volumen de contraste y la radiación, evaluada como producto dosis-área, Kerma-aire y tiempo de fluoroscopia en pacientes a los que se les realizan procedimientos coronarios invasivos.

Abstract Background: Invasive coronary procedures involve the administration of iodinated contrast and the exposure to ionising radiations, increasing morbidity and mortality. The rotational coronary angiography (RCA) allows acquiring multiple projections with a unique injection of iodinated contrast. To date, there are no meta-analyses specifically comparing RCA and conventional coronary angiography (CCA) in patients undergoing invasive coronary procedures, whether diagnostic or diagnostic and therapeutic. The aim of this meta-analysis is to assess the impact of RCA on the amount of iodinated contrast and the exposure to ionising radiations during invasive coronary procedures. Methods: A search in PubMed and Ovid databases was conducted to identify studies, including diagnostic and diagnostic and therapeutic studies, comparing RCA and CCA. The manuscripts were evaluated on quality and biases, and were included if they analysed any of the following endpoints: volume of contrast and exposure to ionising radiations measured as dose-area product, and Kerma-air or fluoroscopy time. Results: Sixteen studies, with a total of 2,327 patients, were included in the final analysis (1,146 patients underwent RCA and 1,181 patients underwent CCA), with significant differences being detected in volume of contrast (standard difference in means (95% confidence interval) −1.887 (−2.472 to −1.302); P < .001), dose-area product (−0.726 (−1.034 to −0.418); P < .001), Kerma-air (−0.842 (−1.104 to −0.581); P < .001), and fluoroscopy time (0.263 (−0.496 to −0.030); P = .027). Conclusions: RCA reduces the volume of contrast and the exposure to radiation, evaluated as dose-area product, Kerma-air, and fluoroscopy time, in patients undergoing invasive coronary procedures.

Comparison between multiparametric MRI with and without post - contrast sequences for clinically significant prostate cancer detection

ABSTRACT Background: Dynamic-contrast enhanced (DCE) sequence is used to increase detection of small lesions, based on increased vascularization. However, literature is controversy about the real incremental value of DCE in detection of clinically significant (CS) prostate cancer (PCa), since absence of enhancement does not exclude cancer, and enhancement alone is not definitive for tumor. Purpose: To test the hypothesis that DCE images do not increase CS PCa detection on MRI prior to biopsy, comparing exams without and with contrast sequences. Material and Materials and Methods: All men who come to our institution to perform MRI on a 3T scanner without a prior diagnosis of CS PCa were invited to participate in this study. Reference standard was transrectal prostate US with systematic biopsy and MRI/US fusion biopsy of suspicious areas. Radiologists read the MRI images prospectively and independently (first only sequences without contrast, and subsequently the entire exam) and graded them on 5-points scale of cancer suspicion. Results: 102 patients were included. Overall detection on biopsy showed CS cancer in 43 patients (42.2%), clinically non-significant cancer in 11 (10.8%) and negative results in 48 patients (47%). Positivities for CS PCa ranged from 8.9% to 9.8% for low suspicion and 75.0% to 88.9% for very high suspicion. There was no statistical difference regarding detection of CS PCa (no statistical difference was found when compared accuracies, sensitivities, specificities, PPV and NPV in both types of exams). Inter-reader agreement was 0.59. Conclusion: Exams with and without contrast-enhanced sequences were similar for detection of CS PCa on MRI.

Marcación de nódulos pulmonares con lipiodol bajo tomografía computada: experiencia local y correlación anatomopatológica / Marking of pulmonary nodules with lipiodol by computerized tomography: local experience and anatomopathological correlation

El objetivo de este estudio es la descripción de la novedosa y poco invasiva técnica de marcación de pequeños nódulos pulmonares con lipiodol, guiado con TAC para su posterior resección por cirugía videotoracoscópica con apoyo radioscópico. Se trata de un estudio retrospectivo que incluye 51 pacientes consecutivos en un tiempo comprendido entre junio del 2012 a septiembre del 2017, obteniendo el diagnóstico final mediante la correlación anatomopatológica, representando los procesos malignos el 81% y los benignos el 19%. Mediante esta técnica se lograron identificar y extraer con éxito el 100% de los nódulos marcados, demostrándose la efectividad y seguridad del procedimiento por las mínimas complicaciones relacionadas.

The purpose of this study is describing a novel and minimally invasive technique of CT-guided marking of small pulmonary nodules with lipiodol prior to resection by videothoracoscopic surgery with radioscopic support. This is a retrospective study that includes 51 consecutive patients between June 2012 and September 2017, with the final diagnosis confirmed by pathology. Malignant nodules represented 81% of the cases with the remaining 19% being benign nodules. Through this technique, 100% of the marked nodules were successfully identified and extracted with few procedure related complications and no adverse clinical outcome, demonstrating the effectiveness and safety of the procedure.

Life-Threatening Thrombocytopenia Following Intravenous Contrast Media Infusion

Radiocontrast media-induced acute severe thrombocytopenia is a very rare complication and potentially life-threatening. Here, we report the case of a 63-year-old male patient with severe acute thrombocytopenia following first exposure to intravenous non-ionic contrast media without immediate allergic reactions. His platelet count dropped from 107000/µL to 2000/µL after six hours of radiocontrast infusion. After administration of corticosteroid and transfusion of platelet concentrates, the platelet count returned gradually to normal within 5 days. To the best of our knowledge, non-ionic contrast media-induced isolated acute severe thrombocytopenia following no signs or symptoms of immediate allergic reaction has never been described.

Study on the Correlation between Barium Radiography and Pulmonary Infection rate in the Evaluation of Swallowing Function

OBJECTIVES: To compare the results respectively obtained from the utilization of 60% barium sulfate suspension and Iohexol as contrast agents for videofluoroscopic swallowing studies and the relationship between the clinical application of the two kinds of contrast agents and the incidence of pneumonia. METHODS: Sixty cases of stroke patients with dysphagia were selected in rehabilitation department of our hospital, and the gender, age, position of the disease, and stroke nature between groups had no significant difference. Among which, 30 patients who were administered 350 mgI/ml Iohexol, and the other 30 patients with 60% barium sulfate suspension as contrast agent. We performed videofluoroscopic swallowing studies with barium 60% versus Iohexol within 1 week after admission and 2 weeks after admission. RESULTS: After 2 weeks in hospital, the aspiration pneumonia incidence of two groups was statistically significant (p<0.05), the pneumonia incidence of Iohexol group was lower than barium sulfate group which might have a impossble relevance with barium aspiration. CONCLUSIONS: During the videofluoroscopic swallowing study of dysphagia after stroke, barium sulfate can enhance the pneumonia incidence, and Iohexol can be widely applied in videofluoroscopic swallowing study.

Lesão renal aguda induzida por contraste: importância dos critérios diagnósticos para estabelecer a prevalência e o prognóstico na unidade de terapia intensiva / Contrast-induced acute kidney injury: the importance of diagnostic criteria for establishing prevalence and prognosis in the intensive care unit

RESUMO Objetivo: Estabelecer se há superioridade entre os critérios para predizer desfecho clínico desfavorável na lesão renal aguda e nefropatia induzidas por contraste. Métodos: Estudo retrospectivo conduzido em hospital terciário com 157 pacientes submetidos à infusão de contraste radiológico para fins propedêuticos. Resultados: Cumpriram os critérios para inclusão 147 pacientes. Aqueles que cumpriram os critérios de lesão renal aguda induzida por contraste (59) também cumpriram os critérios para nefropatia induzida por contraste (76); 44,3% dos pacientes cumpriram os critérios para o estadiamento pelo sistema KDIGO; 6,4% dos pacientes necessitaram utilizar terapia de substituição renal, e 10,7% dos pacientes morreram. Conclusão: O diagnóstico de nefropatia induzida por contraste foi o critério mais sensível para determinar a necessidade de terapia de substituição renal e óbito, enquanto o KDIGO demonstrou a maior especificidade; na população avaliada, não houve correlação entre o volume de contraste e a progressão para lesão renal induzida por contraste, nefropatia induzida por contraste, diálise de suporte ou óbito.

ABSTRACT Objective: To establish whether there is superiority between contrast-induced acute kidney injury and contrast-induced nephropathy criteria as predictors of unfavorable clinical outcomes. Methods: Retrospective study carried out in a tertiary hospital with 157 patients undergoing radiocontrast infusion for propaedeutic purposes. Results: One hundred forty patients fulfilled the inclusion criteria: patients who met the criteria for contrast-induced acute kidney injury (59) also met the criteria for contrast-induced nephropathy (76), 44.3% met the criteria for KDIGO staging, 6.4% of the patients required renal replacement therapy, and 10.7% died. Conclusion: The diagnosis of contrast-induced nephropathy was the most sensitive criterion for renal replacement therapy and death, whereas KDIGO showed the highest specificity; there was no correlation between contrast volume and progression to contrast-induced acute kidney injury, contrast-induced nephropathy, support dialysis or death in the assessed population.

Imágenes del depósito de gadolinio en el sistema nervioso central / Images of gadolinio deposit in the central nervous system Abstract

Magnetic resonance imaging has been shown to be very useful in the diagnosis and monitoring of multiple diseases affecting the central nervous system. Gadolinium has been used extensively worldwide. It has been estimated that since its introduction more than two hundred million doses of GBCA have been administered globally. Gadolinium-based contrast agents (GBCAs) were long considered medicines with a high safety profile, the literature reports incidences of immediate adverse effects such as headache, dizziness, and altered sense of taste. Studies performed a few years after the introduction of GBCA showed that there were gadolinium deposits in the tissues but their clinical significance was not known. It wasn’t until 2006 when the first reports were published that associated the gadolinium ion tissue deposits from GBCA with a systemic inflammatory entity of the connective tissue similar to scleroderma known as Nephrogenic Systemic Fibrosis (NSF), in patients with chronic renal failure. In 2013, the association between the use of GBCAs and the progressive increase in the signal intensity of the dentate nucleus and the globus pallidus in T1-weighted MRI images without contrast medium, was described for the first time. This review describes the most relevant aspects of the pathophysiology of these findings taking into account their differential diagnosis.

Las imágenes por resonancia magnética han mostrado ser de gran utilidad en el diagnóstico y seguimiento de múltiples enfermedades que afectan el sistema nervioso central. El gadolinio se ha utilizado ampliamente a nivel mundial. Se estima que desde su introducción se han administrado más de doscientos millones de dosis de MCBG en el mundo. Los medios de contraste basados en Gadolinio (MCBG) fueron considerados por mucho tiempo medicamentos con un alto perfil de seguridad, la literatura reporta incidencia de efectos adversos inmediatos como cefalea, mareo y alteración del sentido del gusto. Estudios realizados pocos años después de la introducción de los MCBG mostraron que había depósitos de gadolinio en los tejidos, pero no se conocía su significancia clínica Fue hasta 2006 cuando se publicaron los primeros reportes que asociaban el depósito tisular del ion gadolinio proveniente de los MCBG con una entidad inflamatoria sistémica del tejido conectivo similar a la escleroderma conocida como Fibrosis Sistémica Nefrogénica (FSN) en pacientes con falla renal crónica. En 2013 se describió por primera vez la asociación entre el uso de los MCBG y el aumento progresivo de la intensidad de señal del núcleo dentado y los globos pálidos en las imágenes de RM ponderadas en T1 sin medio de contraste. En esta revisión se describen los aspectos más relevantes de la fisiopatología de estos hallazgos considerando su diagnóstico diferencial.

Evaluación de la intensidad de señal en núcleo dentado, puente, globus pallidus y tálamo en pacientes con esclerosis múltiple: valoración de la retención de gadolinio / Evaluation of signal intensity in dentate nucleus, pons, globus pallidus and thalamus in patients with multiple sclerosis: assessment of gadolinium retention

Introduction: Recently, some studies have reported accumulation of gadolinium in the brain of patients with multiple administrations of gadolinium-based contrast. Patients with multiple sclerosis are subjected to multiple contrasting resonances and could become a population at risk. Objective: To determine whether repeated intravenous exposure to gadolinium is associated with more intensity in the thalamus, dentate nucleus, pons and the globus pallidus. Methods: A retrospective study of 60 patients with MS who had undergone two or more contrasted MRs between 2007 and 2015, was performed. The ratios calculated were: dentate nuclei-to-pons (DNP), thalamus-to-pons (TP), caudate nuclei-to-pons (CNP), globus pallidus-to-thalamus (GPT), globus pallidus-to-pons (GPP), by reviewing simple T1 axial sequences. Relative changes were calculated and compared with the number of contrasted MRs. The concordance between observers and the intraclass correlation coefficient was evaluated. Results: There was no evidence of increased signal intensity in T1 sequences (DNP 0.524, GPT 0.466, GPP 0.684, TP 0.771, CNP 0.352). As there were no differences, the Spearman coefficient showed no correlation between relative changes and the number of resonances performed. Inter-observer agreement was almost perfect (0.982) for all structures. Conclusion: Our study did not find a statistically significant increase in the T1 signal intensity in patients with multiple sclerosis. However, there are factors to consider, such as the type of gadolinium and the time lapse between administrations.

Introducción: Recientemente, algunos estudios han informado acumulación de gadolinio en el cerebro de los pacientes con múltiples administraciones de contraste basado en gadolinio. Los pacientes con esclerosis múltiple son sometidos a múltiples resonancias contrastadas y podrían convertirse en una población de riesgo. Objetivo: Determinar si la exposición repetida por vía intravenosa a gadolino se asocia con mayor intensidad en el tálamo, el dentado, el puente y el globo pálido. Métodos: Se realizó un estudio retrospectivo núcleo de 60 pacientes con EM que habían sido sometidos a dos o más RM contrastadas entre 2007 - 2015. Se calcularon las razones núcleo dentado - puente (DNP), tálamo-puente (TP), núcleo caudado- puente (CNP), globus pallidus - tálamo (GPT), globus pallidos - puente (GPP), revisando secuencias T1 axiales simples. Se calcularon los cambios relativos y se compararon con el número de RM contrastadas. Se evaluó la concordancia entre observadores con el coeficiente de correlación intraclase. Resultados: No hubo evidencia de aumento de la intensidad de la señal en secuencias T1 (DNP 0,524, 0,446 GPT, GPP 0,684, 0,771 PT, CNP 0.352). Al no existir diferencias, el coeficiente de Spearman no mostró correlación entre los cambios relativos y el número de resonancias realizadas. La concordancia interobservador fue casi perfecta (0.982) para todas las estructuras. Conclusión: Nuestro estudio no encontró un aumento estadísticamente significativo en la intensidad de la señal T1 en pacientes con esclerosis múltiple. Sin embargo, hay factores a considerar, tales como el tipo de gadolinio y el lapso de tiempo entre las administraciones.

The Effectiveness of Ferritin as a Contrast Agent for Cell Tracking MRI in Mouse Cancer Models

PURPOSE: We aimed to investigate the effectiveness of ferritin as a contrast agent and a potential reporter gene for tracking tumor cells or macrophages in mouse cancer models. MATERIALS AND METHODS: Adenoviral human ferritin heavy chain (Ad-hFTH) was administrated to orthotopic glioma models and subcutaneous colon cancer mouse models using U87MG and HCT116 cells, respectively. Brain MR images were acquired before and daily for up to 6 days after the intracranial injection of Ad-hFTH. In the HCT116 tumor model, MR examinations were performed before and at 6, 24, and 48 h after intratumoral injection of Ad-hFTH, as well as before and every two days after intravenous injection of ferritin-labeled macrophages. The contrast effect of ferritin in vitro was measured by MR imaging of cell pellets. MRI examinations using a 7T MR scanner comprised a T1-weighted (T1w) spin-echo sequence, T2-weighted (T2w) relaxation enhancement sequence, and T2*-weighted (T2*w) fast low angle shot sequence. RESULTS: Cell pellet imaging of Ad-hFTH in vitro showed a strong negatively enhanced contrast in T2w and T2*w images, presenting with darker signal intensity in high concentrations of Fe. T2w images of glioma and subcutaneous HCT116 tumor models showed a dark signal intensity around or within the Ad-hFTH tumor, which was distinct with time and apparent in T2*w images. After injection of ferritin-labeled macrophages, negative contrast enhancement was identified within the tumor. CONCLUSION: Ferritin could be a good candidate as an endogenous MR contrast agent and a potential reporter gene that is capable of maintaining cell labeling stability and cellular safety.

Accidental catheterization of epidural venous plexus: tomographic analysis / Cateterização acidental do plexo venoso peridural: análise tomográfica

ABSTRACT BACKGROUND AND OBJECTIVES: Inadvertent venous catheterizations occur in approximately 9% of lumbar epidural anesthetic procedures with catheter placement and, if not promptly recognized, can result in fatal consequences. The objective of this report is to describe a case of accidental catheterization of epidural venous plexus and its recording by computed tomography with contrast injection through the catheter. CASE REPORT: A female patient in her sixties, physical status II (ASA), underwent conventional cholecystectomy under balanced general anesthesia and an epidural with catheter for postoperative analgesia. During surgery, there was clinical suspicion of accidental catheterization of epidural venous plexus because of blood backflow through the catheter, confirmed by the administration of a test dose through the catheter. After the surgery, a CT scan was obtained after contrast injection through the catheter. Contrast was observed all the way from the skin to the azygos vein, passing through anterior and posterior epidural venous plexuses and intervertebral vein. CONCLUSION: It is possible to identify the actual placement of the epidural catheter, as well as to register an accidental catheterization of the epidural venous plexus, using computed tomography with contrast injection through the epidural catheter.

RESUMO JUSTIFICATIVA E OBJETIVOS: A cateterização venosa inadvertida ocorre em aproximadamente 9% das anestesias peridurais lombares com introdução de cateter e caso não seja prontamente reconhecida pode trazer consequências fatais. O objetivo deste relato é descrever um caso de cateterização acidental do plexo venoso peridural e o seu registro por tomografia computadorizada com injeção de contraste pelo cateter. RELATO DE CASO: Paciente feminina, sexagenária, estado físico II (ASA), submetida à colecistectomia convencional sob anestesia geral balanceada e peridural com cateter para analgesia pós-operatória. Durante cirurgia houve suspeição clínica de cateterização acidental do plexo venoso peridural, por refluxo de sangue pelo cateter, fato confirmado pela administração de dose-teste pelo cateter. Feita tomografia computadorizada com injeção de contraste pelo cateter, após o termino da cirurgia. Observado todo o trajeto do contraste desde a pele até a veia ázigo, passando pelo plexo venoso peridural anterior, posterior e veia intervertebral. CONCLUSÃO: É possível a identificação do real posicionamento do cateter peridural, bem como o registro da cateterização acidental do plexo venoso peridural, por meio de tomografia computadorizada com injeção de contraste pelo cateter peridural.

Proteína C-Reativa Ultrassensível em Pacientes Submetidos a Exames Contrastados / High-Sensitivity C-Reactive Protein in Patients Undergoing Contrast Studies

A utilização de agentes iodados em exames radiológicos pode causar nefropatia induzida porcontraste (NIC) na presença de fatores de risco clássicos, como doença renal prévia e diabetes. Recentemente,níveis séricos elevados de proteína C-reativa ultrassensível (PCR-us) têm sido descritos como indicadores de maior risco de NIC. Independente da ocorrência de NIC, a PCR-us pode elevar-se após exames contrastados.Objetivo: Investigar o comportamento da PCR-us em pacientes submetidos à administração parenteral de agentede contraste iodado. Métodos: Estudo observacional, transversal, prospectivo, realizado no Hospital Universitário Antônio Pedro, de 2007 a 2014, envolvendo 51 pacientes, 30 homens e 21 mulheres, média de idade 60,19±20,0 anos, submetidos aexames com contraste de baixa osmolalidade (Iopamidol 612 mg/mL).Resultados: NIC ocorreu em 15 pacientes (29,4%). Não houve correlação entre a PCR-us aumentada e a ocorrência de NIC. O aumento percentual da PCR-us foi significativamente maior entre os pacientes submetidos ao cateterismocardíaco (p=0,0044). O aumento médio da PCR-us nos pacientes submetidos ao cateterismo cardíaco e naquelessubmetidos à administração do contraste iodado por veia periférica foi 100,3% e 13,8%, respectivamente.Conclusão: Os achados sugerem que o aumento da PCR-us após cateterismo cardíaco não pode ser atribuído aoagente de contraste iodado...

Background: The use of iodinated agents in radiological studies can cause contrast-induced nephropathy (CIN) in the presence of classic risk factors such as previous renal disease and diabetes. High serum levels of high-sensitivity C-reactive protein (CRP) have been described as indicators of increased risk of CIN. Regardless of the occurrence of CIN, hs-CRP may rise after contrast studies. Objective: To investigate the behavior of hs-CRP in patients undergoing parenteral administration of iodinated contrast agent. Methods: Observational cross-sectional prospective study held at Hospital Universitário Antônio Pedro from 2007 to 2014 involving 51 patients, 30 men and 21 women, mean age 60.19±20.0, undergoing tests with low-osmolality contrast (Iopamidol 612mg/ml).Results: CIN occurred in 15 patients (29.4%). There was no correlation between increased hs-CRP and occurrence of CIN. The percentage increase in hs-CRP was significantly higher among patients undergoing cardiac catheterization (p=0.0044). The mean increase in hs-CRP in patients undergoing cardiac catheterization and in those submitted to administration of iodinated contrast by peripheral vein was 100.3% and 13.8%, respectively.Conclusion: The findings suggest that increased hs-CRP after cardiac catheterization cannot be attributed to iodinated contrast agente...

Acceso radial derecho versus izquierdo para cateterismo coronario en pacientes mayores de 70 años / Right versus Left radial artery access for coronary angiography in elderly

Introducción: El acceso radial izquierdo (ARI) puede ser una alternativa para la realización de cateterismos coronarios, especialmente en pacientes añosos, donde modificaciones anatómicas pueden dificultar el procedimiento por acceso radial derecho (ARD). Objetivo: Determinar si el uso del ARI en pacientes mayores de 70 años disminuye el tiempo de fluoroscopía y la dosis de radiación durante una coronariografía realizada por operadores entrenados. Métodos: De forma prospectiva se evaluaron pacientes mayores de 70 años sometidos a cateterismo coronario por vía radial por operadores experimentados (>200 procedimiento por vía radial/año), utilizando la misma técnica. El acceso derecho o izquierdo fue asignado de forma aleatoria y se registraron los tiempos de procedimiento, la exposición a radiación, insumos utilizados y apreciación de dificultad del operador. Resultados: Se incluyeron 102 pacientes (ARD 52 / ARI 50). Ambos accesos fueron comparables en los tiempos utilizado para realizar el procedimiento (ARD 782 vs ARI 695 segundos, p= 0,06), aunque hubo un significativo menor tiempo utilizado para canular la arteria coronaria derecha en aquellos pacientes que se accedieron por ARI (206 vs 169 segundos; p= 0,01). No hubo diferencias en la radiación producida por el examen entre ambos grupos (PDA ARD 56,7 vs ARI 59,3 Gy/ cm2, p= 0,09), ni en la cantidad de medio de contraste utilizado (ARD 106,33 (31,04) vs ARI 108,13 (30,23), p=0,24). Se encontró una mayor frecuencia de tortuosidad (25% vs 6%, p <0,01) y de dificultad del procedimiento (58% vs 28%, p <0,01) en el grupo de ARD, principalmente debido al uso de una guía adicional (33% vs 4%, p< 0,01). Conclusión: Tanto el acceso radial derecho como el izquierdo son alternativas factibles para la realización de una coronariografía en pacientes de edad avanzada, no existiendo diferencias entre éstos en el tiempo total del procedimiento. Sin embargo, el ARD en pacientes añosos se asocia más frecuentemente con dificultades a nivel braquiocefálico y mayor uso de guías adicionales para sortear estos desafíos.

Background: Left radial access (LRA) for coronary angiography is an alternative to right radial access (RRA), especially in elderly patients in whom anatomic features may complicate the latter approach. Aim: To determine whether LRA in patients 70 years or older involves a decreased fluoroscopy time and radiation doses in coronary angiography performed by experienced operators. Method: Patients 70 years or older were randomly assigned to undergo coronary angiography through de RRA (n=52) or LRA (n=50). The procedure was performed by experienced operators (>200 radial access coronary angiographies, yearly). Duration of the procedure, exposure to radiation, materials used and subjective evaluation of the difficulty in performing the angiography were assessed. Results: Mean procedure duration was similar between accesses (RRA = 782 vs LRA = 695 seconds (p=0.06). The time to access the right coronary artery was significantly greater for de RRA compared to the LRA (206 vs 169 seconds, respectively, p=0.01). There was no difference in radiation dose (PDA) between groups (RRA = 106.3 ± 31.4 vs LRA = 108.1 ± 30.2 Gy/cm2, p=0.24), nor in the amount of contrast (ARD 106,33 (31,04) vs ARI 108,13 (30,23), p=0,24). Tortuosity (25% vs 6%, p <0,01) and subjective evaluation of procedure difficulties (58% vs 28%, p <0,01) were higher in RRA compared to LRA. An additional guide was needed with RRA compared to LRA (33% were higher in RRA compared to LRA, an additional guide was used in RRA 33% than in LRA (33% vs 4%, p< 0,01). Conclusion: RRA may be used in elderly patients within the same procedure duration compared to LRA. However, RRA is more frequently associated to the presence of tortuosity at the brachio-cephalic site, leading to greater use of additional wire.