Objective: Despite the high sensitivity and specificity of ventilation/perfusion (VQ) scintigraphy in the diagnosis of chronic thromboembolic pulmonary hypertension (CTEPH) and chronic thromboembolic disease (CTED), V/Q scintigraphy cannot distinguish whether the thrombus is acute or chronic. In our study, we aimed to compare pulmonary computed tomography angiography (CTA) findings with V/Q scintigraphy findings in CTEPH and CTED patients and to identify findings that would indicate chronic thrombus.
Subjects and methods: Eighteen patients diagnosed with CTEPH and CTED at our institution were included in the study between January 2020 and January 2024. Computed tomography angiographyfindings were recorded as V/Q findings [location (segmental, subsegmental, lobar), number, appearance (wedge or patchy) of mismatch perfusion defects], and the correlation of these findings was investigated.
Results: The average age of 18 patients was 63.3±11.7, 66.7% were female and the majority of the patients were non-smokers, and no significant difference was detected between the CTED and CTEPH groups. Apart from the areas where chronic thrombus was localized on CTA, more widespread mismatch defects were observed by VQ scintigraphy. Most of the mismatch defects were wedge-shaped and there was similarity between groups. The presence of mosaic perfusion was detected in 62.5% of those with mismatch patchy defects (P=0.043). A negative correlation was detected between pulse oxygen saturation and the number of mismatch subsegmentary defects (r: -0.651, P=0.005). Systolic pulmonary artery pressure (sPAP) was found to be positively correlated with the number of mismatch defects (r: 0.523, P=0.026).
Conclusion: Ventilation/perfusionscintigraphy is superior in the diagnosis of CTEPH/CTED. The presence of mismatch patch defects on V/Q scintigraphy in patients with clinical, echocardiographic, and CTA findings suggests that the presence of mismatch patch defects on V/Q scintigraphy may be a sign of chronic thrombus and the number of mismatch defects may be correlated with the severity of the disease.
Objective: This study compares volume-based metabolic parameters in early-stage invasive ductal breast cancer using different standardized uptake value (SUV) thresholds and examines their association with immunohistochemical factors.
Subjects and methods: A retrospective analysis included 135 patients with early-stage invasive ductal breast cancer who underwent preoperative fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scans. Metabolic tumor volume (MTV) and total lesion glycolysis (TLG) were derived using absolute SUV threshold methods and fixed % maximum tumor SUV threshold methods. Associations with immunohistochemical factors were explored, and receiver operating characteristic curves were generated.
Results: Metabolic tumor volume 2.5 and TLG 2.5 showed stronger correlations with maximum tumor SUV values. Metabolic tumor volume 2.0 and TLG 2.0 had superior area under the curve (AUC) values in predicting estrogen and progesterone receptor negativity. Metabolic tumor volume 2.0 and TLG 2.0 were superior in distinguishing low and high-grade tumors.
Conclusion: Absolute SUV threshold methods with a threshold of 2.0 are recommended for calculating volume-based metabolic parameters due to their strong correlation with immunohistochemical factors in invasive ductal breast cancer.
Objective: To analyze the application value of standardized uptake value (SUV) in quantitative single-photon emission computed tomography/computed tomography (SPECT/CT) based on the maximum expectation reconstruction algorithm for diagnosing benign and malignant bone lesions.
Subjects and methods: A retrospective analysis was conducted on the clinical data of 83 patients suspected of bone metastasis who underwent quantitative SPECT/CT bone scans in our hospital from September 2023 to July 2024. A total of 91 high-metabolic bone lesions were outlined for SUV measurement, while the spinal SUV of patients with normal bone metabolism were outlined as the control group (46 vertebral bodies). The maximum SUV (SUVmax), mean SUV (SUVmean), and minimum SUV (SUVmin) of benign lesions (benign group), malignant lesions (malignant group), and the control group were measured and compared. Receiver operating characteristic (ROC) curves were plotted to analyze the diagnostic value of SUV in differentiating benign and malignant bone lesions using quantitative SPECT/CT.
Results: Based on the final diagnosis determined by pathology and/or imaging follow-up for 6-12 months or more, 50 malignant bone lesions and 41 benign bone lesions were identified. The levels of SUVmax, SUVmean, and SUVmin in the malignant and benign groups were higher than those in the control group, with the malignant group showing higher levels than the benign group (P<0.05). Receiver operating characteristic curve analysis showed that the areas under the curves for SUVmax, SUVmean, and SUVmin were 0.867, 0.909, and 0.896, respectively. The optimal cut-off value for SUVmax was 26.58g/mL, with a specificity of 100% and a sensitivity of 65.27%; for SUVmean, the optimal cutoff value was 12.75g/mL, with a sensitivity of 78.36% and a specificity of 93.54%; for SUVmin, the optimal cut-off value was 9.13g/mL, with a sensitivity and specificity of 81.42% and 89.87%, respectively. The diagnostic detection rate of quantitative SPECT/CT fusion imaging combined with SUVmean analysis (91.21%) was higher than that of conventional SPECT/CT fusion imaging qualitative analysis (74.73%) (P<0.05).
Conclusion: Standardized uptake value in quantitative SPECT/CT to some extent supplements the qualitative analysis of tumor bone metastasis and benign bone lesions, offering a higher accuracy in diagnosing tumor bone metastasis and differentiating between benign and malignant lesions compared to conventional SPECT/CT bone fusion imaging.
Fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) is a multimodal imaging technique that combines PET and CT, utilizing FAP inhibitors as radiotracers. Fibroblast activation protein, a serine protease highly expressed in many epithelial tumor-associated fibroblasts, plays a crucial role in tumor stroma formation and remodeling. Through the detection of FAP expression, FAPI PET/CT facilitates the diagnosis and staging of both benign and malignant pulmonary tumors. In contrast to traditional fluorine-18-fluorodeoxyglucose (18F-FDG) PET/CT focusing on glucose metabolism, FAPI PET/CT offers benefits such as enhanced specificity, reduced background noise, accelerated imaging speed, and decreased radiation exposure. This review provides an overview of the progress in applying FAPI PET/CT and 18F-FDG PET/CT in pulmonary malignancies and discusses current challenges and future prospects.
Objective: Positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) are complementary in staging of nasopharyngeal carcinoma (NPC). The combination of MRI and functional imaging from PET in PET/MR is promising in NPC management. Diagnostic performance of PET/CT and PET/MR was compared in 46 patients with histologically confirmed NPC under different disease scenarios, including primary non-metastatic cases, primary metastatic cases, recurrence and/or metastasis after treatment, and post-treatment follow-up cases.
Subjects and methods: Forty-six patients underwent both PET/CT and PET/MR in the same day. Primary tumor extension into risk-stratified anatomic structures, retropharyngeal and cervical lymph node metastasis, distant metastasis and post-treatment follow-up results, were compared.
Results: For high-risk structures, PET/MR detected two more sides of tensor/levator veli palatine muscle involvement, one more case of clivus involvement, and ruled out 12 false-positive sides of prevertebral muscle involvement by PET/CT. For medium-risk structures, PET/MR detected four more sides of medial pterygoid muscle involvement. For low-risk structures, abnormal signal on massa lateralis atlantis was detected by PET/MR. PET/MR detected 14 more positive retropharyngeal lymph nodes and more liver micrometastases than PET/CT. Overall, PET/MR changed two patients' T staging.
Conclusion: Positron emission tomography/MR outperforms PET/CT in delineating muscle, skull-base bone, and nodal involvement, and identifying liver micrometastases, may serve as a single-step staging modality for NPC.
Objective: Cryptococcus, a genus of fungi, primarily includes Cryptococcus neoformans and Cryptococcus gattii, both known to cause human infections. Skeletal infections are rare, and there have been no reported cases of bone cryptococcal infection in conjunction with differentiated thyroid carcinoma.
Subject and methods: A 56-year-old female presented with a one-month history of "cough and throat irritation." Chest CT revealed scattered small nodules in both lungs,suggestive of metastasis.There was minimal inflammation in both lungs, and scattered lymph nodes were observed in the mediastinum and upper pulmonary hilum.
Results: The patient was diagnosed with differentiated thyroid carcinoma complicated by cryptococcal infection. Antifungal treatment with itraconazole 200mg/day was initiated, and after 3 months, clinical symptoms disappeared, with a reduction in lung nodules observed in follow-up chest CT.
Conclusion: When diagnosing distant metastasis in differentiated thyroid carcinoma, a comprehensive analysis combining imaging studies and serum thyroid globulin plays a complementary role, as illustrated in this case of differentiated thyroid carcinoma concurrent with cryptococcal infection.
Objective: This paper reviews the current status and future development of positron emission tomography/magnetic resonance (PET/MR) co-imaging technology in the field of cardiovascular diseases.
Material and methods: By combining PET and MRI, PET/MR co-imaging provides comprehensive assessment advantages by simultaneously offering functional and anatomical information.
Results: Firstly, the basic principles of PET/MR are introduced, and the current state is discussed. Subsequently, a detailed discussion on the application of PET/MR in the diagnosis of cardiovascular diseases, including early detection and comprehensive assessment of conditions like coronary artery disease and myocarditis, is presented. Finally, the challenges and future prospects in PET/MR applications are outlined.
Conclusion: Despite facing several technical challenges, PET/MR co-imaging technology is expected to play a crucial role in the early diagnosis, treatment, and research of cardiovascular diseases, paving the way for new directions and possibilities in future medical imaging research.
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