El dilema clínico frente a los pacientes con ergometría positiva y prueba de perfusión miocárdica con SPECT normal / The clinical dilemma facing patients with positive stress test and normal SPECT myocardial perfusion imaging

La evaluación de la perfusión miocárdica con SPECT combina una prueba de esfuerzo (ergometría o estrés farmacológico) junto a imágenes de perfusión con radioisótopos. Este estudio es útil para establecer el diagnóstico de enfermedad arterial coronaria, estratificar el riesgo de infarto y tomar decisiones terapéuticas. Un resultado normal aporta un alto valor predictivo negativo, es decir, una muy baja probabilidad de que el paciente presente eventos cardiovasculares. El hallazgo de signos de isquemia en la ergometría podría poner en jaque el valor predictivo negativo de una perfusión normal. En presencia de este resultado, el paso siguiente es evaluar los predictores de riesgo en la ergometría, el riesgo propio del paciente en función de los antecedentes clínicos y el puntaje cálcico coronario, cuando este se encuentra disponible. Ante la presencia concomitante de otros marcadores de riesgo se sugiere completar la evaluación con un estudio anatómico.El uso de nuevas tecnologías podría mejorar la precisión en la predicción de eventos. (AU)

Assessment of myocardial perfusion with SPECT combines a stress test (ergometry or pharmacological stress) with radioisotope perfusion imaging. This test is helpful to diagnose coronary artery disease, stratify the risk of heart attack, and make therapeutic decisions. A normal result provides a high negative predictive value; therefore, the probability of cardiovascular events is very low. Signs of ischemia on an ergometry could jeopardize the negative predictive value of normal perfusion. In this clinical setting, the next step is to evaluate the risk predictors in the stress test, the individual risk based on the clinical history, and the coronary calcium score when available. Given the simultaneous presence of other risk markers,completing the evaluation with an anatomical study is suggested. The use of new technologies could improve the accuracy of event prediction. (AU)

Validation of automated image co-registration integrated into in-house software for voxel-based internal dosimetry on single-photon emission computed tomography images / Validação do corregistro automático de imagem integrado a software de análise de dosimetria interna baseada em voxel para tomografia computadorizada de emissão de fóton único

Abstract Objective: To develop an automated co-registration system and test its performance, with and without a fiducial marker, on single-photon emission computed tomography (SPECT) images. Materials and Methods: Three SPECT/CT scans were acquired for each rotation of a Jaszczak phantom (to 0°, 5°, and 10° in relation to the bed axis), with and without a fiducial marker. Two rigid co-registration software packages-SPM12 and NMDose-coreg-were employed, and the percent root mean square error (%RMSE) was calculated in order to assess the quality of the co-registrations. Uniformity, contrast, and resolution were measured before and after co-registration. The NMDose-coreg software was employed to calculate the renal doses in 12 patients treated with 177Lu-DOTATATE, and we compared those with the values obtained with the Organ Level INternal Dose Assessment for EXponential Modeling (OLINDA/EXM) software. Results: The use of a fiducial marker had no significant effect on the quality of co-registration on SPECT images, as measured by %RMSE (p = 0.40). After co-registration, uniformity, contrast, and resolution did not differ between the images acquired with fiducial markers and those acquired without. Preliminary clinical application showed mean total processing times of 9 ± 3 min/patient for NMDose-coreg and 64 ± 10 min/patient for OLINDA/EXM, with a strong correlation between the two, despite the lower renal doses obtained with NMDose-coreg. Conclusion: The use of NMDose-coreg allows fast co-registration of SPECT images, with no loss of uniformity, contrast, or resolution. The use of a fiducial marker does not appear to increase the accuracy of co-registration on phantoms.

Resumo Objetivo: Desenvolver corregistro automático e testar seu desempenho com ou sem marcador fiducial em imagens de tomografia computadorizada de emissão de fóton único (SPECT). Materiais e Métodos: Três SPECT/CTs foram adquiridas para cada rotação de um simulador de Jaszczak em relação ao eixo da maca (0°, 5° e 10°), com e sem fiducial. Dois métodos de corregistro inelástico foram aplicados - SPM12 e NMDose-coreg -, e a porcentagem do erro quadrático médio (%RMSE) foi usada para analisar a qualidade do corregistro. Uniformidade, contraste e resolução foram medidos antes e após o corregistro. NMDose com corregistro automático foi usado para calcular a dose renal de 12 pacientes tratados com 177Lu-DOTATATE e comparado com OLINDA/EXM. Resultados: A marcação fiducial não modificou a qualidade do corregistro das imagens SPECT, medida pela %RMSE (p = 0,40). Não houve impacto na uniformidade, contraste e resolução após o corregistro de imagens adquiridas com ou sem fiduciais. Aplicação clínica preliminar mostrou tempo total de processamento de 9 ± 3 min/paciente para NMDose e 64 ± 10 min/paciente para OLINDA/EXM, com alta correlação entre ambos, apesar de menor dose renal em NMDose. Conclusão: NMDose-coreg permite o corregistro rápido de imagens SPECT, sem perda de uniformidade, contraste ou resolução. O uso da marcação fiducial não aumentou a precisão do corregistro em fantomas.

Ambient dose equivalent in 99mTcO4- single photon emission computed tomography of the thyroid among patients with hyperthyroidism / 预防医学

Objective@#To investigate the changes of ambient dose equivalent rate in 99mTcO4- single photon emission computed tomography (SPECT) of the thyroid among patients with hyperthyroidism, so as to provide insights into radiation protection guidance.@*Methods@#Patients with hyperthyroidism who underwent 99mTcO4- SPECT of the thyroid in a tertiary hospital were enrolled. The ambient dose equivalent rate was measured at different time points following 99mTcO4- infection and at sites with different distances from patients' neck, and the effects of time post-injection, distance from patients' neck, 24-hour thyroidal radioiodine uptake and thyroid weight on the ambient dose equivalent rate were examined using a generalized linear mixed model.@*Results@#Totally 100 patients with hyperthyroidism were enrolled, including 24 men and 76 women and with a mean age of (38.5±14.0) years. The generalized linear mixed model was statistically significant (F=6 610.165, P<0.001), and patients' thyroid weight, time post-injection and distance from patients' neck significantly affected the ambient dose equivalent rate (F=57.967, 15 988.574, 11 200.645, all P<0.001), and the ambient dose equivalent rate positively correlated with patients' thyroid weight and negatively correlated with time post-injection and distance from patients' neck.@*Conclusions@#The ambient dose equivalent rate is affected by patients' thyroid weight, time post-injection and distance from patients' neck among patients with hyperthyroidism undergoing 99mTcO4- SPECT of the thyroid. Delay in contact with patients or keeping distance from patients may be effective for radiation protection.

Parotid duct anastomosis with an epidural catheter as a stent and evaluation of postoperative gland function / 口腔疾病防治

Objective @#To investigate the feasibility of epidural catheters in parotid gland duct anastomosis and the function of the affected side gland after parotid gland duct anastomosis. @* Methods@# Thirteen patients who were treated in the Department of Oral and Maxillofacial Surgery of Xuzhou Central Hospital using an epidural catheter as the scaffold for parotid gland catheter anastomosis were enrolled from Jan. 2019 to June 2021. The swelling, salivary fistula and catheter patency in the parotid gland area were evaluated two weeks after the operation. 99mTcO4- single photon emission computed tomography (SPECT) was used for quantitative detection of salivary gland secretion function@*Results@# Thirteen patients had no swelling or salivary fistula in the parotid gland area of the affected side two weeks after the operation, and the catheter secretion was unobstructed. There was no significant difference in the uptake rate between the parotid gland on the affected side and the parotid gland on the healthy side (t = -0.859, P = 0.399), and there was no significant difference in the excretion rate between the parotid gland on the affected side and the parotid gland on the healthy side (t = 0.693, P = 0.495). The parotid gland excretion function of the affected side was excellent three months after the operation.@*Conclusion @#Parotid duct anastomosis with an epidural catheter as the stent has good feasibility, and parotid gland secretion function recovers well after the operation, which is worthy of clinical application.

Crossed aphasia in a left-handed patient with non-fluent variant of primary progressive aphasia with left asymmetric brain SPECT / Afasia cruzada em paciente canhota com afasia progressiva primária variante não fluente com SPECT cerebral assimétrico à esquerda

ABSTRACT Primary progressive aphasia is a clinical syndrome caused by neurodegeneration of areas and neural networks involved in language, usually in the left hemisphere. The term "crossed aphasia" denotes an acquired language dysfunction caused by a lesion in the ipsilateral hemisphere to the dominant hand. Objective: To describe a case of crossed aphasia in a 60-year-old left-handed patient with a non-fluent variant of primary progressive aphasia diagnosis (age of onset=52), evidenced by a left asymmetry on brain SPECT scan. Methods: Clinical and family history, the Edinburgh Handedness Inventory, Measurement of Functional Activities in Older Adults in the Community, the "Mini-Mental State Examination", the Trail Making Test, the Tower of London, and the Neuropsychological assessment for dementia, and neuroimaging studies were carried out. Results: Neuropsychological assessment showed severe cognitive impairment, especially regarding language. The magnetic resonance imaging showed important signs of cortico-subcortical atrophy, with predominance in the frontal and temporal lobes. The single-photon emission computed tomography scan showed moderate to severe hypoperfusion in the left cerebral hemisphere, including the hippocampus. Conclusion: We described a clinical case of crossed aphasia in a left-handed woman with a non-fluent variant of primary progressive aphasia with asymmetry on brain SPECT, mainly on the left, followed up for seven years.

RESUMO A afasia progressiva primária é uma síndrome clínica causada por uma neurodegeneração de áreas e redes neurais envolvidas na linguagem, geralmente no hemisfério esquerdo. O termo "afasia cruzada" denota uma disfunção adquirida de linguagem causada por uma lesão no hemisfério ipsilateral da mão dominante. Objetivo: Relatamos um caso de afasia cruzada em uma paciente de 60 anos, canhota, com um quadro clínico de afasia progressiva primária variante não fluente (idade de início=52), evidenciada por assimetria no SPECT cerebral à esquerda. Métodos: Foram realizados para o diagnóstico do caso: história clínica e familiar, o Inventário de Dominância de Edinburgh, a Escala de Atividades Funcionais de Pfeffer, o Miniexame do Estado Mental, o Teste das Trilhas, o Teste da Torre de Londres, a Avaliação Neuropsicológica Adequada às Demências e exames de neuroimagem. Resultados: A avaliação neuropsicológica mostrou comprometimento cognitivo severo, principalmente sobre a linguagem; a ressonância magnética do crânio mostrou sinais de involução córtico-subcortical, com predominância nos lobos frontal e temporal e a cintilografia cerebral por emissão de fóton único mostrou hipoperfusão moderada a severa no hemisfério cerebral esquerdo, incluindo o hipocampo. Conclusão: Registramos um caso clínico de afasia cruzada em uma paciente canhota com afasia progressiva primária variante não fluente com assimetria no SPECT cerebral, principalmente à esquerda, seguida há sete anos.

Conectividad funcional a partir de la perfusión cerebral en pacientes epilépticos y con enfermedad de Parkinson

Introducción: La epilepsia y la enfermedad de Parkinson han sido descritos como trastornos de redes neurales. El estudio de la conectividad por modalidades moleculares puede ser más relevante fisiológicamente que los basados en señales hemodinámicas. Objetivo: Proponer una metodología para la descripción de patrones de conectividad funcional a partir de la perfusión cerebral por tomografía por emisión de fotón único. Métodos: La metodología incluye cuatro pasos principales: preprocesamiento espacial, corrección del volumen parcial, cálculo del índice de perfusión y obtención de la matriz de conectividad funcional mediante el coeficiente de correlación de Pearson. Se implementó en 25 pacientes con distintos trastornos neurológicos: 15 con epilepsia farmacorresistente y 10 con enfermedad de Parkinson. Resultados: Se encontraron diferencias significativas entre los índice de perfusión de varias regiones de los hemisferios ipsilateral y contralateral tanto en pacientes con epilepsia del lóbulo frontal como en pacientes con epilepsia del lóbulo temporal. Igual resultado se obtuvo en los pacientes con enfermedad de Parkinson con distintos estadios de la enfermedad. Para cada grupo se identificaron patrones de conectividad funcional que involucran a regiones relacionadas con la patología en estudio. Conclusiones: Con el desarrollo de esta metodología se ha demostrado que la tomografía por emisión de fotón único aporta información valiosa para estudiar la organización de las redes funcionales del cerebro. Futuras investigaciones con mayor número de pacientes contribuirían a hacer inferencias sobre los correlatos neurales de los distintos trastornos cerebrales.

Introduction: Epilepsy and Parkinson's disease have been described as disorders of neural networks. The study of connectivity by molecular modalities may be more physiologically relevant than those based on hemodynamic signals. Aim: The aim of the present work is to propose a methodology for the description of functional connectivity patterns from brain perfusion by single photon emission tomography. Methods: The methodology includes four main steps: spatial preprocessing, partial volume correction, calculation of the perfusion index and obtaining the functional connectivity matrix using Pearson's correlation coefficient. It was implemented in 25 patients with different neurological disorders: 15 with drug-resistant epilepsy and 10 suffering Parkinson's disease. Results: Significant differences were found between the perfusion indexes of various regions of the ipsilateral and contralateral hemispheres in both patients with frontal lobe epilepsy and patients with temporal lobe epilepsy. The same result was obtained in Parkinson's disease patients with different stages of the disease. For each group, functional connectivity patterns involving regions related to the pathology under study were identified. Conclusions: With the development of this methodology, it has been demonstrated that single photon emission tomography provides valuable information to study the organization of functional brain networks. Future research with a larger number of patients would contribute to make inferences about the neural correlates of the different brain disorders.

Current status and prospect of preoperative assessment of heart disease risk in liver transplant recipients / 器官移植

With the changes of the disease spectrum of liver transplantation and organ allocation system, more and more patients complicated with cardiovascular complications have entered the waiting list for liver transplantation. However, surgical stress, severe infection and adverse reactions of immunosuppressive drugs will significantly increase the risk of postoperative cardiac complications and affect the short-and long-term survival of the recipients. Therefore, comprehensive evaluation of cardiac structure and function of the recipients before liver transplantation is of significance for improving clinical prognosis of the recipients. In this article, the main causes for the increased risk of heart disease during the perioperative period of liver transplantation, the time and methods of heart disease risk assessment for liver transplant recipients were reviewed, and existing assessment approaches for common heart diseases before liver transplantation were illustrated, aiming to provide reference for further reducing the incidence of heart complications after liver transplantation, improving the survival rates of grafts and recipients and enhancing clinical prognosis.

Progress in application of single-photon emission computed tomography/computed tomography (SPECT/CT) imaging in clinical practice / 中国辐射卫生

@#The combination of conventional single-photon emission computed tomography (SPECT) and computed tomography (CT) may display the morphological changes of lesions and distribution of imaging agents, which is effective to improve the imaging sensitivity and specificity of tumors and non-tumor diseases. SPECT/CT is feasible to analyze the anatomical structure and metabolic status through displaying multi-site lesions with single imaging, thereby improving differential diagnosis and diagnostic accuracy of diseases. In addition, the novel mixed SPECT/CT device shortens the duration of image acquisition and provides precise attenuation correction and fusion imaging, which provides a scientific basis for rational selection of treatment regimens in clinical practice. This review describes the advances in clinical application of SPECT/CT.

Application of 99Tc m-MIBI SPECT/CT imaging in patients with primary cervical dystonia / 中华核医学与分子影像杂志

Objective:To evaluate the value of 99Tc m-methoxyisobutylisonitrile(MIBI) SPECT/CT imaging for the identification of dystonic muscles in patients with primary cervical dystonia (PCD). Methods:A total of 10 patients with PCD (3 males, 7 females, age (47.3±9.9) years) and 10 healthy subjects (4 males, 6 females, age (43.5±9.4) years; control group) between August 2019 and October 2021 in China-Japan Friendship Hospital were enrolled prospectively. All subjects underwent 99Tc m-MIBI SPECT/CT scan. The SUV max of 8 bilateral representative muscles, including rectus capitis posterior major, obliquus capitis inferior, splenius capitis, semispinalis, sternocleidomastoid, trapezius, musculus scalenus muscle and levator scapulae were evaluated in control group. In PCD group, muscles with abnormal uptake were determined. ROI was drawn and SUV max was measured. Independent-sample t test was used to analyze the differences of SUV max between normal and abnormal muscles. The detecting rates of neck MRI and SPECT/CT for abnormal muscles were analyzed by χ2 test. Results:Normal muscles of healthy subjects showed mild symmetrical radioactivity distribution, with the SUV max of 1.10±0.19. A total of 60 muscles with abnormal uptake in 10 patients were found, including 7 rectus capitis posterior major, 10 obliquus capitis inferior, 8 splenius capitis, 8 semispinalis, 10 sternocleidomastoid, 5 trapezius, 3 musculus scalenus muscle and 9 levator scapulae. The SUV max of muscles with abnormal uptake was 1.81±0.43, which was higher than that of normal muscles ( t=17.05, P<0.001). Only 30 pieces abnormal hypertrophy muscle were found by neck MRI, and the detecting rate was much lower than that of SPECT/CT (18.75%(30/160) vs 37.50%(60/160); χ2=28.03, P<0.001). Conclusion:99Tc m-MIBI SPECT/CT may be a useful method for identifying dystonic muscles and a guide to precision therapy in patients with PCD.

Value of SPECT myocardial perfusion imaging and coronary flow reserve combined with coronary artery calcium score in the diagnosis of obstructive coronary artery disease / 中华核医学与分子影像杂志

Objective:To study the value of myocardial perfusion imaging (MPI) and coronary flow reserve (CFR) combined with coronary artery calcium score (CACS) in the diagnosis of obstructive coronary artery disease (CAD).Methods:From January 2019 to December 2020, 96 confirmed or suspective CAD patients (65 males, 31 females; age: 30-81 years) who completed rest/stress MPI, CFR and CACS defection in Fuwai Central China Cardiovascular Hospital were retrospectively analyzed. Coronary angiography (CAG) was used as the diagnostic standard to calculate the sensitivity and accuracy of MPI, CFR and MPI/CFR combined with CACS in the diagnosis of CAD. The χ2 test was used to compare the diagnostic efficiency of different methods. Results:The diagnostic sensitivity of MPI was 76.06%(54/71), and the accuracy was 75.00%(72/96), while the sensitivity increased to 97.18%(69/71; χ2=13.67, P<0.001) and the accuracy increased to 87.50%(84/96; χ2=4.92, P=0.020) with significant differences after combined with CACS. The sensitivity and accuracy of CFR were 91.55%(65/71)and 87.50%(84/96), which increased to 97.18%(69/71; χ2=2.12, P=0.137) and 89.58%(86/96; χ2=0.21, P=0.411) with no significant differences after combined with CACS. The sensitivity of MPI in the diagnosis of three-vessel CAD was 70.00%(21/30), which increased to 100%(30/30; χ2=7.75, P=0.004) after combined with CACS; while the sensitivity of MPI combined with CACS in the diagnosis of single-vessel and double-vessel CAD were not significantly improved ( χ2 values: 3.29, 1.51, P values: 0.114, 0.416). Conclusion:The combination of MPI and CACS can significantly improve the diagnostic efficiency of CAD, contributed by the improvement of the diagnostic sensitivity in three-vessel disease; whereas the diagnostic efficiency of CFR for CAD is not significantly improved after combined with CACS.

Establishment of the normal reference values of left ventricular function parameters evaluated by CZT SPECT stress gated myocardial perfusion imaging in low-likelihood of stable coronary artery disease / 中华核医学与分子影像杂志

Objective:To establish the normal reference value of left ventricular function parameters by cadmium-zinc-tellurium (CZT) SPECT stress gated myocardial perfusion imaging (G-MPI) in low-likelihood of stable coronary artery disease (SCAD).Methods:From March 2022 to August 2022, 348 consecutive SCAD patients (146 males, 202 females, age (58±10) years) who underwent exercise or pharmacological stress G-MPI (CZT SPECT) in Beijing Anzhen Hospital, Capital Medical University were retrospectively recruited. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and left ventricular ejection fraction (LVEF) were acquired using quantitative gated SPECT (QGS) analysis. EDV and ESV were corrected by body surface area (BSA) to obtain EDV index (EDVI) and ESV index (ESVI), respectively. Independent-sample t test, one-way analysis of variance and Mann-Whitney U test were used for data analysis. The influences of EDV, ESV, EDVI, ESVI and LVEF were analyzed by multiple regressions for linear models. Results:There were 314 patients with low-likelihood of SCAD (128 males, 186 females, age (58±10) years) and 34 normal controls (18 males, 16 females, age (55±10) years). There were no significant differences of basic clinical characteristics and left ventricular function parameters in different genders between 2 groups ( z values: from -1.74 to -0.02, t values: from -1.16 to 1.17, all P>0.05). Using the 95% CI as the cut-off value for left ventricular function parameters in patients with a low-likelihood of SCAD, the upper limits of EDV, ESV, EDVI and ESVI in females and males were 84 and 111 ml, 30 and 44 ml, 47 and 54 ml/m 2, 17 and 21 ml/m 2, respectively, and the lower limit of LVEF in females and males were 58% and 55%, respectively. In the low-likelihood of SCAD group, the EDV ((58±13) vs (77±17) ml) and ESV ((16±7) vs (26±9) ml) of females were smaller than those of males ( t values: 10.65, 10.35, both P<0.001), while LVEF of females was higher than that of males ((72±7)% vs (67±6)%; t=-6.23, P<0.001). However, there were no significant differences in left ventricular function parameters among different age groups with the same gender ( F values: 0.12-2.19, all P>0.05). Based on multiple regression for linear models, the primary predictors of EDV, ESV and LVEF were gender and weight ( β values: from -0.380 to 0.358, all P<0.05). Conclusions:Normal reference values of left ventricular function parameters are established by CZT SPECT stress G-MPI in low-likelihood of SCAD patients. Left ventricular EDV and ESV of females are smaller than those of males, while LVEF of females is higher than that of males. The influence of gender on left ventricular function parameters should be considered in clinical practice.

Relationship between coronary flow reserve by CZT SPECT and invasive coronary fractional flow reserve and its potential clinical value / 中华核医学与分子影像杂志

Objective:To evaluate the relationship between regional coronary flow reserve (CFR) obtained from cadmium-zinc-telluride SPECT(CZT SPECT) myocardial functional perfusion imaging (MFPI) and invasive fractional flow reserve (FFR) measured during coronary angiography (CAG) and its clinical value in guiding coronary interventions.Methods:Forty-two patients (30 males, 12 females, age (63.3±9.8) years) who completed CZT SPECT MFPI in the First Affiliated Hospital of Nanjing Medical University from June 2022 to September 2022 and underwent CAG within 3 months were included retrospectively. The concordance of CFR and FFR for diagnosing myocardial ischemia (CFR<2.0 and FFR<0.8) was calculated at the vascular level. The diagnostic efficacy of coronary stenosis≥70% for decreased myocardial blood flow (CFR<2.0) was calculated. Kappa test was used to analyze the data. Results:A total of 126 major coronary arteries were identified in 42 patients, of which 30(23.8%) had a CFR<2.0 by CZT SPECT and 33(26.2%) had stenosis≥70% in CAG. A total of 32 coronary vessels were performed with MFPI CFR and FFR measurements, of which 6 were both decreased and 21 were both normal, so the concordance rate was 84.4%(27/32)( Kappa=0.612, P<0.001). Among 33 coronary vessels with stenosis≥70%, 13 were with CFR≥2.0. Among 30 coronary vessels with CFR<2.0, 10 were with stenosis<70%. When using stenosis≥70% to diagnose CFR decreasing, the sensitivity was 66.7%(20/30), specificity was 86.5%(83/96), positive predictive value was 60.6%(20/33), negative predictive value was 89.2%(83/93), and accuracy was 81.7%(103/126). Conclusions:The concordance between CFR and FFR for the diagnosis of myocardial ischemia is good. Nearly 1/3 of the coronary arteries with decreased CFR have stenosis<70%, whereas nearly 40% of the coronary arteries with stenosis≥70% are not result in myocardial ischemia. Regional CFR determined by CZT SPECT may have potentially significant clinical value in the diagnosis of coronary artery disease and decision-making of coronary intervention.

Evaluation of the efficacy of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension using pulmonary perfusion tomography imaging / 中华核医学与分子影像杂志

Objective:To evaluate the efficacy of balloon pulmonary angioplasty (BPA) in chronic thromboembolic pulmonary hypertension (CTEPH) using 99Tc m-macroaggregated albumin (MAA) pulmonary perfusion tomography imaging. Methods:Twenty-five patients (4 males, 21 females; age (56.5±12.3) years) with CTEPH who underwent BPA from January 2017 to April 2020 in Beijing Chaoyang Hospital, Capital Medical University were enrolled retrospectively. Effect of BPA on the improvement of pulmonary lobe/pulmonary segment perfusion was analyzed, and the proportions of improved and unimproved pulmonary lobe/pulmonary segment perfusion by BPA were calculated. The percentages of perfusion defect scores (PPDs%) of lung perfusion tomography imaging before BPA and after 4-6 times BPA were compared and analyzed (paired t test). The correlations between PPDs% and mean pulmonary artery pressure (mPAP) before BPA and after BPA were analyzed respectively, and the correlation between decreased percentage of PPDs% and decreased percentage of mPAP after BPA were also analyzed (Pearson correlation analysis). Results:Among 150 lobes of 25 patients, 96.00%(144/150) lobes showed perfusion abnormalities before BPA. After BPA, 11.11%(16/144) showed complete improvement, 57.64%(83/144) showed partial improvement, and 31.25%(45/144) showed no improvement. Among 450 pulmonary segments of 25 patients, 62.44%(281/450) showed perfusion abnormalities before BPA. After BPA, 30.60%(86/281), 37.37%(105/281), 32.03%(90/281) showed complete, partial and no improvement, respectively. The post-BPA PPDs% was significantly lower than that of pre-BPA ((39.08±10.88)% vs (57.88±10.46)%; t=10.40, P<0.001). The post-BPA mPAP was significantly lower than that of pre-BPA ((32.36±10.57) vs (49.08±10.23) mmHg; 1 mmHg=0.133 kPa; t=10.25, P<0.001). There was no significant correlation between PPDs% and mPAP either before BPA ( r=0.01, P=0.953) or after BPA ( r=0.27, P=0.199), but there was a positive correlation between the changes of PPDs% and mPAP ( r=0.40, P=0.045). Conclusions:BPA can significantly improve the pulmonary perfusion and reduce mPAP in CTEPH patients. Pulmonary perfusion tomography imaging can be used to evaluate the efficacy of BPA in CTEPH.

Magnetic resonance and dopamine transporter imaging for the diagnosis of Parkinson´s disease: a narrative review / Ressonância magnética e neuroimagem do transportador de dopamina no diagnóstico da doença de Parkinson: uma revisão narrativa

ABSTRACT Background: the diagnosis of Parkinson's disease (PD) can be challenging, especially in the early stages, albeit its updated and validated clinical criteria. Recent developments on neuroimaging in PD, altogether with its consolidated role of excluding secondary and other neurodegenerative causes of parkinsonism, provide more confidence in the diagnosis across the different stages of the disease. This review highlights current knowledge and major recent advances in magnetic resonance and dopamine transporter imaging in aiding PD diagnosis. Objective: This study aims to review current knowledge about the role of magnetic resonance imaging and neuroimaging of the dopamine transporter in diagnosing Parkinson's disease. Methods: We performed a non-systematic literature review through the PubMed database, using the keywords "Parkinson", "magnetic resonance imaging", "diffusion tensor", "diffusion-weighted", "neuromelanin", "nigrosome-1", "single-photon emission computed tomography", "dopamine transporter imaging". The search was restricted to articles written in English, published between January 2010 and February 2022. Results: The diagnosis of Parkinson's disease remains a clinical diagnosis. However, new neuroimaging biomarkers hold promise for increased diagnostic accuracy, especially in earlier stages of the disease. Conclusion: Future validation of new imaging biomarkers bring the expectation of an increased neuroimaging role in the diagnosis of PD in the following years.

RESUMO Antecedentes: O diagnóstico da doença de Parkinson (DP) pode ser desafiador, principalmente nas fases iniciais da doença, embora tenha critérios clínicos atualizados e validados. Os avanços recentes em neuroimagem na DP, além do seu papel já consolidado de excluir causas secundárias e outras causas neurodegenerativas de parkinsonismo, tem contribuído para uma maior confiabilidade no diagnóstico em diferentes estágios da doença. Nesta revisão, nós destacamos os principais avanços de ressonância magnética e imagem do transportador de dopamina em auxiliar o diagnóstico de DP. Objetivo: realizar uma revisão acerca do conhecimento atual sobre o papel da ressonância magnética e imagem do transportador de dopamina no diagnóstico de doença de Parkinson. Método: Realizamos uma revisão não sistemática da literatura através da base de dados PubMed, utilizando as palavras-chave "Parkinson", "magnetic resonance imaging", "diffusion tensor", "diffusion-weighted", "neuromelanin", "nigrosome-1", "single-photon emission computed tomography", "dopamine transporter imaging". A busca foi restrita a artigos escritos em inglês, publicados entre janeiro de 2010 e fevereiro de 2022. Resultados: O diagnóstico de doença de Parkinson continua sendo um diagnóstico clínico, contudo, novos biomarcadores de neuroimagem são promissores para o aumento da acurácia diagnóstica, especialmente em fases mais precoces da doença. Conclusão: A validação futura de novos biomarcadores de imagem traz a expectativa de um maior papel da neuroimagem no diagnóstico de doença de Parkinson nos próximos anos.

Calidad de la imagen de tomografía computarizada versus dosis en estudios híbridos: resultados preliminares en maniquí

RESUMEN Fundamento: los estudios híbridos producen una dosis total de radiación que es resultado de la dosis proveniente del radiofármaco y la emitida por la tomografía computarizada, por eso la optimización es indispensable. Objetivo: evaluar la relación de la dosis de tomografía computarizada con algunos parámetros de calidad de la imagen en protocolos de estudios híbridos. Métodos: para evaluar la calidad de la imagen se emplearon los maniquíes de Catphan y de Livermore en 12 protocolos preestablecidos de un equipo de tomografía por emisión del fotón único Mediso. Los datos de los descriptores de dosis de cada estudio se obtuvieron del cabezal DICOM. Se compararon los parámetros de calidad de imagen clásicos como ruido y la MTF 50 % para el maniquí de Catphan, y otros como la relación contraste ruido, el promedio de números de Hounsfield y su desviación estándar en las regiones de interés de los órganos correspondientes, en el maniquí de Livermore. Se analizó la relación de estos parámetros de calidad con los descriptores de dosis de los diferentes protocolos. Resultados: los parámetros relacionados con la calidad en el maniquí de Catphan no mostraron diferencias significativas (p<0,05) entre los diferentes protocolos para estudios híbridos. Se encontraron diferencias significativas entre los protocolos clínicos con diferentes calidades y el protocolo clínico estándar, para el maniquí antropomórfico, en la desviación estándar de los números de Hounsfield y en la relación contraste ruido (p<0,05). Conclusiones: el estudio de la relación contraste ruido y la desviación de los números de tomografía computarizada en las regiones de interés pueden servir de parámetro cuantitativo para la optimización de dosis en escenario clínico.

ABSTRACT Background: hybrid studies produce a total radiation dose that is the result of the dose imparted by the radiopharmaceutical and that emitted by the computed tomography, therefore optimization is essential. Objective: to evaluate the relationship of the computed tomography dose with some image quality parameters in hybrid study protocols. Methods: to evaluate the image quality, the Catphan and Livermore Phantom were used in 12 pre-established protocols of a Mediso single photon emission tomography equipment. The data for the dose descriptors for each study were obtained from the DICOM head. The classic image quality parameters such as noise and the MTF 50% for the Catphan manikin, and others such as the contrast-noise ratio, the average of Hounsfield numbers and their standard deviation in the regions of interest of the corresponding organs were compared, in Livermore's mannequin. The relationship of these quality parameters with the dose descriptors of the different protocols was analyzed. Results: the quality-related parameters in the Catphan manikin did not show significant differences (p <0.05) between the different protocols for hybrid studies. Significant differences were found between the clinical protocols with different qualities and the standard clinical protocol, for the anthropomorphic manikin, in the standard deviation of the Hounsfield numbers and in the contrast-to-noise ratio (p <0.05). Conclusions: the study of the contrast noise ratio and the deviation of the computed tomography numbers in the regions of interest can serve as a quantitative parameter for the optimization of doses in the clinical setting.

Rat thyroid graft transplantation after cryopreservation with scintigraphic standardization for an experimental study

Abstract Purpose: Budget cuts among other factors undermine the use of state-of-the-art equipment by many research groups. This doesn't mean that their scientific data are not reliable or top-notch. Resort to adaptations is a recurrent need in their reality. The aim of this study was to assess whether scintigraphy with 99mTcO4 is effective in evaluating the functionality of thyroid grafts after cryopreservation in rats. Material and methods: 24 rats were randomly distributed into 3 groups: Control Group (CG), without surgical procedure, Hypothyroidism Group (HTG), submitted to total thyroidectomy, and Transplanted Group (TG), with total thyroidectomy and cryopreservation of the thyroid gland for 7 days followed by grafting of a thyroid lobe. A protocol using a gamma camera imaging was conducted fourteen weeks after transplantation, and the whole body 99mTc, focusing on the topic of heterotopic thyroid uptake was evaluated. Results: The images acquired had good quality with no noise and artifacts that could jeopardize its analysis. On the 14th day, HTG displayed no thyroid uptake, and the TG had a clear uptake of the thyroid graft in the topography of the biceps femoris muscle. Presented data also showed that both equipment spatial resolution and alignment (4.375 mm) did not interfere with the physiological uptake of 99mTc by the thyroid graft. Conclusion: The viability and functionality of cryopreserved thyroid autotransplantation in rats who underwent total thyroidectomy were successfully accessed by the scintigraphy protocol developed. HIGHLIGHTS Adaptations in validated methods are a recurrent trend due to limited budgets which does not diminish their functionality. Scintigraphy with 99mTcO4 is effective in evaluating the functionality of thyroid grafts after cryopreservation in rats. It is possible to adapt human SPECT for other animals for clinical and research purposes.

Comparison of IQ-SPECT and low energy high-resolution collimator SPECT in clinical application / 中华核医学与分子影像杂志

Objective:To investigate differences in cardiac function and perfusion parameters measured by IQ-SPECT and low energy high-resolution (LEHR)-SPECT, as well as effects of scattering correction (SC) and CT attenuation correction (AC) on myocardial perfusion imaging.Methods:From May 2020 to September 2020, 80 patients (58 males, 22 females, age (57±10) years) who underwent SPECT myocardial perfusion imaging were retrospectively enrolled in Fuwai Hospital. According to the standardized left ventricular end-diastolic diameter of body surface measured by two-dimensional echocardiography, patients were divided into 2 groups: A group ( n=34) with significantly enlarged left ventricle and B group ( n=46) with no significant enlargement of left ventricle. LEHR-SPECT and IQ-SPECT gated myocardial perfusion imaging were performed in all patients. Left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), summed rest score (SRS) and total perfusion defect (TPD) were measured. Parameters measured by two methods and differences before and after SC and AC were compared by using paired t test and Wilcoxon signed rank test. The correlation was analyzed by Pearson correlation or Spearman rank correlation analyses, and the consistency was analyzed by Bland-Altman analysis. Results:In A group, EDV, EF and SRS measured by IQ-SPECT were significantly lower than those assessed by LEHR-SPECT after SC and AC (EDV: (257±137) vs (276±154) ml, EF: (21±11)% vs (26±13)%, SRS: 17(6, 25) vs 18(8, 28); t values: -2.63, -7.46, z=-2.14, all P<0.05); all parameters measured by LEHR-SPECT and IQ-SPECT had well correlation ( r values: 0.965, 0.969, 0.967, rs values: 0.920, 0.960, all P<0.001) and consistency. In B group, EDV and EF measured by IQ-SPECT were significantly lower than those assessed by LEHR-SPECT after SC and AC (EDV: (96±40) vs (107±39) ml, EF: (46±15)% vs (54±16)%; t values: -6.23, -10.71, both P=0.001); SRS and TPD measured by IQ-SPECT after SC and AC were significantly lower than non-SC and non-AC (SRS: 2(1, 4) vs 5(3, 11), TPD: (3%(1%, 5%) vs 7%(3%, 12%); z values: -4.11, -4.16, both P<0.001); all parameters measured by LEHR-SPECT and IQ-SPECT had well correlation ( r values: 0.956, 0.978, 0.958, rs values: 0.926, 0.944, all P<0.001) and consistency. Conclusions:There are good correlation and consistency of left ventricular function and myocardial perfusion parameters acquired by IQ-SPECT and LEHR-SPECT. Moreover, IQ-SPECT is able to shorten acquisition time, resulting in great potential in clinical application.

Serially evaluation of changes in myocardial perfusion, hibernation myocardium and left ventricular function in the development of chronic coronary artery occlusion by gated SPECT perfusion and gated PET imaging in pigs / 中华核医学与分子影像杂志

Objective:To serially characterize the myocardial perfusion, myocardial hibernation and left ventricular (LV) function as well as LV remodeling in progressive coronary artery stenosis in Chinese mini-pigs.Methods:In 8 Chinese mini-pigs (5 males, 3 females; age: 10 months), chronic progression of coronary stenosis and finally occlusion was established using Ameroid constrictor implantation at the 1 cm below the bifurcation of the first diagonal branch of the left anterior descending (LAD) artery. Serial gated 99Tc m-methoxyisobutylisonitrile(MIBI) SPECT/CT, gated 18F-FDG PET/CT imaging and coronary angiography (CAG) were performed before surgery and at the 1st, 4th and 8th week after surgery. Longitudinally, total perfusion defect (TPD), LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), summed motion score (SMS), summed thickening score (STS) and hibernating myocardium (HM) were analyzed. Repeated measures analysis of variance, Kruskal-Wallis rank sum test and Bonferroni correction method were used to analyze data. Results:One mini-pig died of infection after the Ameroid constrictor implantation. In the remaining 7 mini-pigs, TPD was progressively increased with time prolonged (0, 12.0%(0, 33.0%), (41.1±23.7)% and (49.3±24.5)%; H=17.03, P=0.001); Compared with HM before the surgery (100%), HM was gradually reduced from the 1st (21.0%(6.0%, 100%)) to the 4th (18.0%(3.0%, 33.0%)) week after surgery, and then increased to the 8th week after surgery ((23.0±15.4)%; H=13.09, P=0.004), but there was no significant difference between the 1st and 4th week, or between the 4th and 8th week after surgery (both P>0.05 (Bonferroni correction method)). Accordingly, LVEF gradually decreased ((73.7±8.4)%, (63.7±19.1)%, (53.7±14.6)% and (49.9±15.4)%; F=6.22, P=0.004). LVEDV (9.0(6.0, 21.0), (31.4±16.3), (32.9±17.4) and (36.4±17.5) ml; H=8.58, P=0.035)and LVESV ((3.8±3.2), (15.9±15.3), 12.0(10.0, 17.0)and (19.3±10.9) ml; H=10.51, P=0.015) gradually increased. SMS and STS continuously increased as well ( H values: 16.49, 13.33, P values: 0.001, 0.004). Conclusions:With the progression of coronary artery stenosis to occlusion, myocardial perfusion is gradually decreased, while the global and regional LV function, LV remodeling are gradually aggravated, and HM is gradually reduced. After the chronic coronary artery occlusion, myocardial perfusion has a trend to be improved and HM is gradually recovered.

Primary study of motion correction effect on myocardial blood flow quantitative imaging with CZT SPECT / 中华核医学与分子影像杂志

Objective:To investigate the effect of motion correction (MC) on the calculated values of myocardial blood flow (MBF) and myocardial flow reserve (MFR) based on cadmium-zinc-telluride SPECT (CZT SPECT) images.Methods:Twenty-eight consecutive patients (10 males, 18 females, age: (60.75±11.62) years) with suspected or known coronary artery disease who underwent myocardial perfusion imaging (MPI) with dynamic CZT SPECT between June 2019 and August 2019 in TEDA International Cardiovascular Hospital were retrospectively analyzed. The MBF and MFR during rest imaging and stress imaging were quantitatively analyzed. Corridor 4DM software was used to calculate the stress MBF (sMBF) and MFR of the coronary artery branches and left ventricular (LV) before and after MC. The paired t test and Pearson correlation were used for data analysis. Results:The sMBF and MFR of LV before MC were (0.82±0.49) ml·min -1·g -1 and 1.69±0.68 respectively. After MC the two parameters increased to (1.05±0.64) ml·min -1·g -1 and 2.12±0.77 respectively ( t values: -4.87, -6.01, both P<0.001). The sMBF and MFR in left anterior descending (LAD), left circumflex (LCX), right coronary artery (RCA) and LV before MC were correlated with those after MC ( r values: 0.69-0.96, all P<0.001). If MFR <2.0 was used as the reference of impaired MFR, data before MC showed 19 patients (67.9%, 19/28) had impaired MFR, while 13 patients (46.4%, 13/28) had impaired MFR based on MFR values after MC. Conclusion:For MPI quantitative imaging with CZT SPECT, the calculated values of sMBF and MFR after MC is higher than those before MC, suggesting that MC is helpful to reduce the false positive results which may be caused by the " creep" effect of the heart.

Assessment of left ventricular diastolic dyssynchrony and its influencing factors early after acute myocardial infarction by SPECT gated myocardial perfusion imaging: an experimental study / 中华核医学与分子影像杂志

Objective:To evaluate the left ventricular diastolic dyssynchrony (LVDD) and its influencing factors early after acute myocardial infarction (AMI) using phase analysis of SPECT gated myocardial perfusion imaging (GMPI).Methods:Bama miniature swines ( n=16) were subjected to establish AMI models. GMPI was performed before and 1 d after AMI to obtain the extent of myocardial perfusion defect (Extent, %) and left ventricular systolic dyssynchrony (LVSD)/LVDD parameters, namely the phase histogram bandwidth (PBW) and phase standard deviation (PSD). Meanwhile, left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), and the ratio of early to late peak mitral diastolic flow (E/A) were obtained by echocardiography. Independent-sample t test, paired t test and Pearson correlation analysis were used to analyze the data. Results:Sixteen AMI swines were successfully created. Compared to baseline, Extent, LVEDV and LVESV significantly increased on 1 d after AMI ( t values: -11.14, -4.55, -6.12, all P<0.001), while LVEF and E/A significantly decreased ( t values: 10.16, 2.18, P<0.001, P=0.046). GMPI showed that the LVDD parameters PBW and PSD increased significantly on 1 d after AMI when compared to those at baseline((142.25±72.06)° vs (33.06±8.98)°, (56.15±26.71)° vs (12.51±5.13)°; t values: -6.11, -6.60, both P<0.001). There were significant differences between LVSD parameters and LVDD parameters (PBW: (109.06±62.40)° vs (142.25±72.06)°, PSD: (44.40±25.61)° vs (56.15±26.71)°; t values: -2.73, -2.20, P values: 0.016, 0.044). LVDD parameters PBW, PSD were negatively correlated with E/A after AMI ( r values: -0.569, -0.566, P values: 0.021, 0.022), and positively correlated with the Extent ( r values: 0.717, 0.634, P values: 0.002, 0.008). The phase analysis of SPECT GMPI to evaluate LVDD showed good intra-observer and inter-observe reproducibility (intraclass correlation coefficient (ICC): 0.953-0.984, all P<0.001). Conclusions:LVDD occurs early on 1 d after AMI, and can reflect left ventricular diastolic dysfunction. The Extent is correlated with LVDD significantly. Phase analysis of SPECT GMPI is an accurate method to evaluate LVDD and left ventricular diastolic function.