A region-level contrastive learning-based deep model for glomerular ultrastructure segmentation on electron microscope images / 南方医科大学学报

OBJECTIVE@#We propose a novel region- level self-supervised contrastive learning method USRegCon (ultrastructural region contrast) based on the semantic similarity of ultrastructures to improve the performance of the model for glomerular ultrastructure segmentation on electron microscope images.@*METHODS@#USRegCon used a large amount of unlabeled data for pre- training of the model in 3 steps: (1) The model encoded and decoded the ultrastructural information in the image and adaptively divided the image into multiple regions based on the semantic similarity of the ultrastructures; (2) Based on the divided regions, the first-order grayscale region representations and deep semantic region representations of each region were extracted by region pooling operation; (3) For the first-order grayscale region representations, a grayscale loss function was proposed to minimize the grayscale difference within regions and maximize the difference between regions. For deep semantic region representations, a semantic loss function was introduced to maximize the similarity of positive region pairs and the difference of negative region pairs in the representation space. These two loss functions were jointly used for pre-training of the model.@*RESULTS@#In the segmentation task for 3 ultrastructures of the glomerular filtration barrier based on the private dataset GlomEM, USRegCon achieved promising segmentation results for basement membrane, endothelial cells, and podocytes, with Dice coefficients of (85.69 ± 0.13)%, (74.59 ± 0.13)%, and (78.57 ± 0.16)%, respectively, demonstrating a good performance of the model superior to many existing image-level, pixel-level, and region-level self-supervised contrastive learning methods and close to the fully- supervised pre-training method based on the large- scale labeled dataset ImageNet.@*CONCLUSION@#USRegCon facilitates the model to learn beneficial region representations from large amounts of unlabeled data to overcome the scarcity of labeled data and improves the deep model performance for glomerular ultrastructure recognition and boundary segmentation.

Multimodal assessment in polymicrobial infective endocarditis with silent spondylodiscitis and cerebral embolism / Evaluación multimodal en endocarditis infecciosa polimicrobiana con espondilodiscitis silenciosa y embolia cerebral

Abstract Infective endocarditis (IE) is a rare but severe disease, due to an infection of the endocardial surface of the heart. The annual incidence ranging from 3 to 7 per 100 000 person-years, with an overall mortality rates of 25%. Staphylococci and Streptococci accounted for approximately 80% of IE cases. Enterococci are the third leading cause accounted for approximately 5-18% of all cases and are increasingly linked to health-care contact. The increasing number of cardiovascular electronic devices, prosthetic valves implants along with frequent invasive diagnostic or therapeutic procedures performed in elderly, may also contribute to the rise of IE in this population. Blood cultures and echocardiographic findings are the cornerstone of the IE diagnosis, confirmed or rejected according to modified Duke criteria. Other imaging modalities as Cardiac Computed Tomography, Cardiac Magnetic Resonance Imaging and 18Ffluorodeoxyglucose Positron Emission Tomography - Computed Tomography (18FDG-PET/CT) can determine a more correct diagnosis and identify many of the endocarditis-related complications. Here, we describe a patient with aortic prosthetic valve and Enterococcus faecalis (EF) IE. Cerebral and spinal MRI and 18FDG-PET/CT, performed during the hospitalization, showed multi-organ silent periferic embolization. Furthermore, the cultural examination of the valvular surgical specimen revealed a methicillin-sensitive Staphylococcus aureus suggestive for polymicrobial endocarditis. Some Authors demonstrated a possible false-positive valve culture due to a postoperative contamination. Since contaminated cultures usually yield microorganisms compatible with endocarditis, such as coagulase-negative Staphylococci, viridans group Streptococcus species, may be difficult for the physician not to treat the patient. This case represents need for high level of suspicion to diagnose IE. Multimodality assessment improves the diagnosis and allows the detection of the complications. Moreover, a multidisciplinary team and specialized centers determine a better patient’s outcome.

Resumen La endocarditis infecciosa (EI) es una enfermedad poco frecuente pero severa, dada por una infección del endocardio. La incidencia anual oscila entre 3 y 7 por cada 100 000 personas-año, con una tasa de mortalidad general del 25%. Los estafilococos y los estreptococos representaron aproximadamente un 80% de los casos de EI. Los enterococos son la tercera causa, aportando aproximadamente 5% a 18% de todos los casos, y se vinculan cada vez más al contacto con la atención médica. El número creciente de dispositivos electrónicos cardiovasculares e implantes de válvulas protésicas, junto con los frecuentes procedimientos invasivos diagnósticos o terapéuticos en las personas ancianas, también podrían contribuir al incremento de EI en esta población. Los hemocultivos y los hallazgos ecocardiográficos son la piedra angular del diagnóstico de EI, confirmado o rechazado de acuerdo con los criterios modificados de Duke. Otras modalidades de imagenología tales como la Tomografía Computarizada Cardíaca (TCC), la Resonancia Magnética Cardíaca (RMC) y la Tomografía por Emisión de Positrones - Tomografía Computarizada con 18F-fluorodeoxiglucosa (18F-FDG PET/TC) pueden determinar un diagnóstico más preciso e identificar muchas de las complicaciones asociadas a la endocarditis. Aquí describimos un paciente con una válvula aórtica protésica y EI por EF. Una RM del cerebro y la columna vertebral y una 18F-FDG PET/TC practicadas durante la hospitalización evidenciaron embolia periférica multiorgánica silenciosa. Además, el examen por cultivo de la muestra quirúrgica valvular reveló Staphylococcus aureus sensible a la meticilina (SASM), sugestivo de endocarditis polimicrobiana. Algunos autores demostraron un posible falso positivo del cultivo valvular dado por contaminación postoperatoria. Ya que los cultivos contaminados generalmente producen microorganismos compatibles con la endocarditis, tales como estafilococos coagulasa negativos y estreptococos del grupo viridans, le puede resultar difícil al médico no tratar al paciente. Este caso representa la necesidad de tener un alto nivel de sospecha para diagnosticar la EI. La valoración multimodal mejora el diagnóstico y permite detectar complicaciones. Además, un equipo multidisciplinario y los centros especializados determinan un mejor desenlace para el paciente.

Design and Test of Automatic Dispensing and Injecting System for Positron Radiopharmaceuticals / 中国医学科学院学报

Objective To design a novel automatic dispensing and injecting system of positron radiopharmaceuticals,for precise dose dispensing,simplified operation,and reduction of occupational radiation exposure. Methods The automatic dispensing and injecting system was fabricated with tungsten alloy as the shielding material.The performance and radiation protection of the device were assessed. Results The total time of injection using the automatic dispensing and injecting system was about 60 s.The ratio of successful injection in stability test was 100%.The deviation of the dispensing dose with the system was ≤3%.With the tungsten alloy shield(40 mmPb of the cabinet,60 mmPb of the countertop,15 mmPb of the protective shield,and 50 mmPb of the inbuilt jar for radiopharmaceuticals),the average dose rate at 30 cm from the device was 1.44 μSv/h,and the radiation dose at the operator's extremity was reduced by 99%. Conclusions This automatic dispensing and injecting system of positron radiopharmaceuticals is easy to operate with precise dispensing dose.It is safe and meets the requirements of radiation protection.

Progress in enhancing electron transfer rate between exoelectrogenic microorganisms and electrode interface / 生物工程学报

Exoelectrogenic microorganisms are the research basis of microbial electrochemical technologies such as microbial fuel cells, electrolytic cells and electrosynthesis. However, their applications are restricted in organic degradation, power generation, seawater desalination, bioremediation, and biosensors due to the weak ability of biofilm formation and the low extracellular electron transfer (EET) efficiency between exoelectrogenic microorganisms and electrode. Therefore, engineering optimization of interaction between exoelectrogenic microorganisms and electrode interface recently has been the research focus. In this article, we review the updated progress in strategies for enhancing microbe-electrode interactions based on microbial engineering modifications, with a focus on the applicability and limitations of these strategies. In addition, we also address research prospects of enhancing the interaction between electroactive cells and electrodes.

Application of Virtual Monochromatic Images Reconstructed by Dual-energy Computed Tomography in Radiotherapy Treatment Planning System / 中国医疗器械杂志

Virtual monochromatic images (VMI) that reconstructed on dual-energy computed tomography (DECT) have further application prospects in radiotherapy, and there is still a lack of clinical dose verification. In this study, GE Revolution CT scanner was used to perform conventional imaging and gemstone spectral imaging on the simulated head and body phantom. The CT images were imported to radiotherapy treatment planning system (TPS), and the same treatment plans were transplanted to compare the CT value and the dose distribution. The results show that the VMI can be imported into TPS for CT value-relative electron density conversion and dose calculation. Compared to conventional images, the VMI varies from 70 to 140 keV, has little difference in dose distribution of 6 MV photon treatment plan.

Potential of electron transfer and its application in dictating routes of biochemical processes associated with metabolic reprogramming / 医学前沿

Metabolic reprogramming, such as abnormal utilization of glucose, addiction to glutamine, and increased de-novo lipid synthesis, extensively occurs in proliferating cancer cells, but the underneath rationale has remained to be elucidated. Based on the concept of the degree of reduction of a compound, we have recently proposed a calculation termed as potential of electron transfer (PET), which is used to characterize the degree of electron redistribution coupled with metabolic transformations. When this calculation is combined with the assumed model of electron balance in a cellular context, the enforced selective reprogramming could be predicted by examining the net changes of the PET values associated with the biochemical pathways in anaerobic metabolism. Some interesting properties of PET in cancer cells were also discussed, and the model was extended to uncover the chemical nature underlying aerobic glycolysis that essentially results from energy requirement and electron balance. Enabling electron transfer could drive metabolic reprogramming in cancer metabolism. Therefore, the concept and model established on electron transfer could guide the treatment strategies of tumors and future studies on cellular metabolism.

Two-Dimensional Electron Beam Radiotherapy Planning System with Modeling Function / 中国医疗器械杂志

In order to adapt to different target shapes and protect the surrounding normal tissues, the design of two-dimensional electron beam radiotherapy planning requires additional lead blocks. But the Pinnacle treatment planning system can not directly shape the lead block conformity to the size of the beam field given by the doctor. Every time, physicists need to manually drag the lead block to form the required beam field. When meeting a two-dimensional electron beam treatment planning with the same field parameters as before, physicists need to rearrange the field for dose calculation, which greatly reduces the design efficiency of the two-dimensional electron beam treatment planning. In this study, we independently developed a two-dimensional electron beam radiotherapy planning system based on Qt Creator. The system can quickly design a two-dimensional electron beam radiotherapy plan, which reduces the repeated work of physicists.

Common Troubles of Vacuum Components in Elekta Linear Accelerator and Fast Solutions / 中国医疗器械杂志

The transportation of electron is inseparable from vacuum environment. The maintenance of the vacuum system of Elekta linear accelerator depends on two sputtering ionic pumps at the gun end and the target end. The traveling wave acceleration were used in Elekta linear accelerators. And the design of the electron gun filament is detachable. Because of these two reasons, the vacuum stability is relatively weak. Only two vacuum values are used to reflect the operation state of the whole vacuum system, which causes a few failures but will not trigger a the machine interlock. Considering the complexity of whole vacuum system, the problem of vacuum caused by the failure of various components in vacuum system is analyzed in this paper. It is hoped that some useful repairing experience and suggestions for the maintenance engineers of linear accelerator to solve the vacuum fault and rebuild the vacuum can be provided quickly.

Application of Statistical Process Control in Evaluation of Performance for Beam-matched Medical Electron Linacs / 中国医疗器械杂志

Clinically, beam matching can greatly improve the flexibility and efficiency of treating patients between different medical electron linacs. However, in addition to the regular quality assurance (QA) test of the machine performance of linacs, there is still a lack of comprehensive evaluation of the clinical radiotherapy performance of beam-matched linacs. In this paper, the performance of volumetric modulated arc therapy (VMAT) between three closely matched linacs was evaluated by statistical process control (SPC) technology. It was found that the average and median γ passing rates of the VMAT QA processes of the three linacs had little difference, but the process capability levels were at three different levels. The results show that SPC technology can effectively evaluate the performance of beam matching for medical electron linacs, improve the patient-specific VMAT QA processes, and guide clinical decision-making.

Performance of F-18 Fluorocholine PET/CT for Detection of Hyperfunctioning Parathyroid Tissue in Patients with Elevated Parathyroid Hormone Levels and Negative or Discrepant Results in conventional Imaging

Recent progress of positron radionuclide labeled small molecule inhibitors of prostate specific membrane antigen for PET/CT imaging of prostate cancer / 生物医学工程学杂志

Prostate cancer is the most common tumor of the urinary system, and its mortality rate is second only to lung cancer. With the specific and high expression on the surface of prostate cancer cells, prostate-specific membrane antigen (PSMA) has been an ideal theranostic target of prostate cancer with great clinical significance and research value. Positron emission tomography/computed tomography (PET/CT), a new modality of molecular imaging combining functional metabolic information and anatomical structure, provides high diagnostic performance for cancer detection. This paper mainly reviewed recent progress of PSMA inhibitors labeled by positron-emitting radionuclides for early diagnosis, preoperative staging, response assessment, restaging and metastasis detection of prostate cancer.

Comportamiento dosimétrico de un sistema de planificación mediante curvas de calibración de densidades electrónicas relativas / Dosimetric behaviour of a planning system through calibration curves of relative electron density

En esta investigación se planteó como objetivo la verificación del comportamiento dosimétrico del Sistema de Planificación de Tratamiento (TPS) de Radioterapia mediante las curvas de calibración de Densidades Electrónicas Relativas (DER). Este estudio se realizó en el Hospital de la Sociedad de Lucha Contra el Cáncer (SOLCA) Núcleo Loja, usando un fantoma antropomorfo CIRS 062M y un tomógrafo Toshiba Activion 16. Para determinar la nueva curva de calibración DER se tomaron los valores de densidades electrónicas especificadas en el manual del fantoma y las Unidades Hounsfield de la imagen tomográfica. Se realizó controles de calidad dosimétricos y verificación dosimétrica en tres casos clínicos: tórax, pelvis y cráneo; para realizar las pruebas dosimétricas se utilizó un acelerador CLINAC CX, cámara de ionización PTW tipo Farmer con volumen sensible de 0,6 cm3 y un electrómetro PTW UNIDOS E. Los resultados mostraron que las medidas para cada inserto del fantoma en ningún caso excedieron los límites establecidos de ± 20 UH, para el tomógrafo y el TPS; las pruebas de control de calidad no superaron el límite máximo de desviaciones en el cálculo de dosis absorbida por el TPS y la obtenida por medición de ± 4 % establecida por la IAEA y las verificaciones dosimétricas en tórax, pelvis y cráneo, determinaron que las desviaciones en el cálculo de la dosis absorbida por el TPS y la obtenida por medición no superaban la tolerancia del ± 5 % establecida por la ICRU.

In this research, the aim was to verify the dosimetric behavior of the Radiotherapy Treatment Planning System (TPS) using the Relative Electron Density (DER) calibration curves. This study was carried out at the SOLCA (Society of Fight Against Cancer) hospital in Loja, using an CIRS model 062M anthropomorphic phantom and a Toshiba Activion 16 tomograph. To determine the new DER calibration curve, the values of the electron densities specified in the manual of the phantom and the Hounsfield Units of the tomographic image were taken. Dosimetric quality controls were made in the location of three clinical cases: thorax pelvis and skull; used a CLINAC CX accelerator was used to perform the dosimetric tests, PTW ionization chamber type Farmer with sensitive volume of 0.6 cm3 and a PTW UNIDOS E electrometer. The results showed that the measurements for each insert of the phantom in no case exceeded the established limits of ± 20 UH, for the tomograph and the TPS; the quality control tests did not exceed the maximum limit of deviations in the calculation of dose absorbed by the TPS and the one obtained by measurement of ± 4% established by the IAEA and the clinical planning in the thorax, pelvis and skull, determine that the deviations in the calculation of the dose absorbed by the TPS and that obtained by measurement, they do not exceed the tolerance of ± 5% established by the ICR.

Management of Arrhythmias Associated with Cardiac Sarcoidosis

Sarcoidosis is a multisystem granulomatous disorder of unknown etiology. The annual incidence of systemic sarcoidosis is estimated at 10–20 per 100,000 individuals. Owing to the recent advances in imaging modalities, cardiac sarcoidosis (CS) is diagnosed more frequently. The triad of CS includes conduction abnormality, ventricular tachycardia, and heart failure. Atrial and ventricular arrhythmias are caused by either inflammation or scar formation. Inflammation should be treated with immunosuppression and antiarrhythmic agents and scar formation should be treated with antiarrhythmics and/or ablation, in addition to implantable cardioverter defibrillator (ICD) implantation, if necessary. Ablation can provide a good outcome, but it might require bipolar ablation if the critical portion is located mid-myocardium. Late recurrence might be caused by reactivation of sarcoidosis, which would need to be evaluated by positron emission tomography-computed tomography imaging. Risk of sudden cardiac death (SCD) in patients with advanced atrioventricular block is not low, and ICD implantation could be considered instead of a pacemaker. For risk stratification for SCD, late gadolinium enhancement by cardiac magnetic resonance imaging or program stimulation is often used.

Diagnosis of an indistinct Leydig cell tumor by positron emission tomography-computed tomography

A 51-year-old perimenopausal female patient presented with hirsutism and voice thickening which was started approximately one and a half years ago. Her initial hormone assay revealed elevated plasma testosterone, 5a-dihydrotestosterone, and dehydroepiandrosterone (DHEA) levels and therefore androgen-secreting tumor was first suspected. However, the lesion was inconspicuous on transvaginal sonography, abdominal-pelvic computed tomography (CT) scan, and pelvic magnetic resonance (MRI) imaging. Consequently, 18F-fluorodeoxyglucose (FDG) positron emission tomography-CT was performed, which localized the lesion as a focal FDG uptake within the right adnexa. Total laparoscopic hysterectomy with bilateral salpingo-oophorectomy was performed, and although visible gross mass lesions were not observed intraoperatively, pure Leydig cell tumor was pathologically confirmed within the right ovary. Plasma testosterone, 5a-dihydrotestosterone, and DHEA levels were normalized postoperatively. Clinical signs of virilization were also significantly resolved after 3-months of follow-up.

Malignant Melanoma of the Pancreas and Liver Mimicking a Neuroendocrine Tumor / 대한내과학회지

Among metastatic pancreatic tumors, malignant melanomas are rare. Here, we report a very rare case of a malignant melanoma that involved only the pancreas and liver, and was difficult to differentiate from a neuroendocrine tumor of the pancreas with a liver metastasis. A 65-year-old- male with no history of a malignant melanoma exhibited hypervascular hepatic and pancreatic tumors on computed tomography and contrast-enhanced endoscopic ultrasonography. He lacked lesions of the skin, eye, and gastrointestinal tract on physical examination, upper endoscopy, and a whole-body positron emission tomography-computed tomography scan; these sites are common primary sites of malignant melanoma. Finally, endoscopic ultrasound-guided pancreatic core biopsy and percutaneous ultrasonography-guided liver biopsy confirmed malignant melanoma of the pancreas and liver.

Recent Update of Advanced Imaging for Diagnosis of Cardiac Sarcoidosis: Based on the Findings of Cardiac Magnetic Resonance Imaging and Positron Emission Tomography

Sarcoidosis is a multisystem disease characterized by noncaseating granulomas. Cardiac involvement is known to have poor prognosis because it can manifest as a serious condition such as the conduction abnormality, heart failure, ventricular arrhythmia, or sudden cardiac death. Although early diagnosis and early treatment is critical to improve patient prognosis, the diagnosis of CS is challenging in most cases. Diagnosis usually relies on endomyocardial biopsy (EMB), but its diagnostic yield is low due to the incidence of patchy myocardial involvement. Guidelines for the diagnosis of CS recommend a combination of clinical, electrocardiographic, and imaging findings from various modalities, if EMB cannot confirm the diagnosis. Especially, the role of advanced imaging such as cardiac magnetic resonance (CMR) imaging and positron emission tomography (PET), has shown to be important not only for the diagnosis, but also for monitoring treatment response and prognostication. CMR can evaluate cardiac function and fibrotic scar with good specificity. Late gadolinium enhancement (LGE) in CMR shows a distinctive enhancement pattern for each disease, which may be useful for differential diagnosis of CS from other similar diseases. Effectively, T1 or T2 mapping techniques can be also used for early recognition of CS. In the meantime, PET can detect and quantify metabolic activity and can be used to monitor treatment response. Recently, the use of a hybrid CMR-PET has introduced to allow identify patients with active CS with excellent co-localization and better diagnostic accuracy than CMR or PET alone. However, CS may show various findings with a wide spectrum, therefore, radiologists should consider the possible differential diagnosis of CS including myocarditis, dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy, amyloidosis, and arrhythmogenic right ventricular cardiomyopathy. Radiologists should recognize the differences in various diseases that show the characteristics of mimicking CS, and try to get an accurate diagnosis of CS.

Developing Consilience Medicine: Positron Emission Tomography Scan and Transcriptomics in Pancreatic Cancer

No abstract available.

Effects of Amisulpride Adjunctive Therapy on Working Memory and Brain Metabolism in the Frontal Cortex of Patients with Schizophrenia: A Preliminary Positron Emission Tomography/Computerized Tomography Investigation

OBJECTIVE: Dopamine plays a significant role in working memory by acting as a key neuromodulator between brain networks. Additionally, treatment of patients with schizophrenia using amisulpride, a pure dopamine class 2/3 receptor antagonist, improves their clinical symptoms with fewer side effects. We hypothesized that patients with schizophrenia treated with amisulpride and aripiprazole show increased working memory and glucose metabolism compared with those treated with cognitive behavioral therapy (CBT) and aripiprazole instead. METHODS: Sixteen patients with schizophrenia (eight in the amisulpride group [aripiprazole+amisulpride] and eight in the CBT group [aripiprazole+CBT]) and 15 age- and sex-matched healthy control subjects were recruited for a 12-week-long prospective trial. An [18F]-fluorodeoxyglucose-positron emission tomography/computerized tomography scanner was used to acquire the images. RESULTS: After 12 weeks of treatment, the amisulpride group showed greater improvement in the Letter-Number Span scores than the CBT group. Additionally, although brain metabolism in the left middle frontal gyrus, left occipital lingual gyrus, and right inferior parietal lobe was increased in all patients with schizophrenia, the amisulpride group exhibited a greater increase in metabolism in both the right superior frontal gyrus and right frontal precentral gyrus than the CBT group. CONCLUSION: This study suggests that a small dose of amisulpride improves the general psychopathology, working memory performance, and brain glucose metabolism of patients with schizophrenia treated with aripiprazole.

Diagnosis of Sarcopenia in Head and Neck Computed Tomography: Cervical Muscle Mass as a Strong Indicator of Sarcopenia

OBJECTIVES: Patients with head and neck cancer (HNC) have a high risk of sarcopenia, which is associated with poor prognosis. Skeletal-muscle area and index at the third lumbar (L3) vertebra level (L3MA and L3MI) are recommended for the detection of sarcopenia. However, L3 level is not included in many imaging protocols and there are no data for optimal levels and cutoffs for the diagnosis of sarcopenia in head and neck computed tomography (HNCT) scans. Our aim was to assess the relationship between cervical paravertebral muscle values and L3MI and to investigate optimal level to diagnose sarcopenia on HNCTs. METHODS: Patients with HNC (n=159) who underwent positron emission tomography-CT for tumor staging were retrospectively analyzed. On CT images, paravertebral and sternocleidomastoid muscle areas at second (C2), third (C3), and fourth (C4) cervical vertebrae levels (C2MA, C3MA, C4MA, SCMA) and L3MA were measured. Cross-sectional areas were normalized for stature (muscle area/height square) and muscle index (C2MI, C3MI, C4MI, SCMI, L3MI) values were obtained. Spearman correlation and linear regression analyses were used for assessing correlations. To calculate the diagnostic performance of SCMI, C2MI, C3MI, and C4MI for the diagnosis of sarcopenia with respect to the cutoffs of L3MI, receiver operating characteristic (ROC) analysis was used. RESULTS: Males had significantly higher muscle areas than females. Although C2MI, C3MI, C4MI, and SCMI values all showed very strong and significant correlation with L3MI (P<0.001). According to the ROC analysis, the best discriminative for sarcopenia was C3MI in males (area under curve [AUC], 0.967) and SCMI in females (AUC, 0.898). CONCLUSION: C2MI, C3MI, C4MI, and SCMI values can be used as alternatives for the diagnosis of sarcopenia in routine HNCT examinations.

Therapeutic Effect of Fimasartan in a Rat Model of Myocardial Infarction Evaluated by Cardiac Positron Emission Tomography with ¹⁸FFPTP / 전남의대학술지

We evaluated the efficacy of fimasartan on perfusion defects and infarction size in an animal model of myocardial infarction (MI), with echocardiography and positron emission tomography (PET) using a ¹⁸F-labeled phosphonium cation (5-[¹⁸F]-fluoropentyl-triphenylphosphonium salt, [¹⁸F]FPTP) as a mitochondrial voltage sensor for myocardial imaging. We induced MI in 33 rats by ligation of the left coronary artery, and checked their cardiac PET image using [¹⁸F]FPTP for evaluation of myocardial perfusion. Rats were grouped into 3 groups according to their administered drugs: no drug (n=11), fimasartan 3 mg/kg (n=10), and fimasartan 10 mg/kg (n=12). Each designated drug was administered for 4 weeks, and follow-up PET and histologic examinations were done. In the PET analysis, a perfusion defect size was markedly improved in fimasartan 10 mg/kg group (35.9±7.0% to 28.4±6.9%, p<0.001), whereas treatment with fimasartan 3 mg/kg induced only an insignificant reduction of perfusion defect size (35.9±7.9% to 33.9±7.3%, p=0.095). Using 2, 3, 5-triphenyltetrazolium chloride staining, infarction size was the largest in the control group (36.5±8.3%), and was insignificantly lower in the fimasartan 3 mg/kg group (31.5±6.5%, p for the difference between the control group=0.146) and was significantly lower in the fimasartan 10 mg/kg group (26.3±7.6%, p for the difference between the control group=0.011). PET imaging using a ¹⁸F-labeled mitochondrial voltage sensor, [¹⁸F]FPTP, is useful in evaluation and monitoring of myocardial perfusion states, and treatment with fimasartan decreases the infarction size in animal MI model.