Clinical Nuclear Medicine最新文献

Pheochromocytomas are tumors originating from neuroendocrine cells in the adrenal medulla, with an incidence of 0.05%. They are most often unilateral (92% of cases) and implicated in ~0.1% of hypertension cases. About 30% of pheochromocytomas are associated with hereditary syndromes such as MEN2, VHL, and NF1. When bilateral, a genetic disease is identified in 80% of patients. While coexistence of pheochromocytoma with pancreatic NETs has been described in Von Hippel-Lindau disease, coexistence of pheochromocytoma with duodenal, jejunal, or ileal NET is very rare: about 20 cases were reported in the literature, synchronous or metachronous, often associated with neurofibromatosis. We describe the case of a 58-year-old patient with a previously unremarkable history, referred to fluorodopa PET/CT for staging of a bilateral pheochromocytoma discovered in front of a typical clinical triad, who was incidentally diagnosed with 2 synchronous neuroendocrine tumors of the small bowel.

Background: This study aims to evaluate the diagnostic value of 18 F-FAPI-42 PET in differentiating glioma recurrence from treatment-related changes, with comparative analyses against 11 C-MET PET and contrast-enhanced MRI (CE-MRI).

Patients and methods: In this prospective study, patients with suspected glioma recurrence underwent concurrent 18 F-FAPI-42 PET/MRI, 11 C-MET PET/MRI, and CE-MRI examinations. Diagnostic performance for differentiating tumor recurrence was evaluated and compared across imaging modalities using McNemar test. Wilcoxon rank-sum tests were used to assess differences in SUVmax and tumor-to-background ratios (TBR) between glioma recurrence and treatment-related changes. Receiver operating characteristic curve analysis was performed to determine optimal cutoff values and compare the diagnostic efficacy of SUVmax and TBR through area under the curve (AUC) metrics.

Results: Among the 76 suspected glioma recurrence patients, 59 were diagnosed with recurrence and 17 had treatment-related changes. When distinguishing between recurrence and treatment-related changes, the accuracy and sensitivity of 18 F-FAPI-42 PET were comparable to those of 11 C-MET PET and CE-MRI (accuracy: 80.26% vs 86.84% vs 78.95%, respectively, all P > 0.05; sensitivity: 89.83% vs 93.22% vs 98.31%, respectively, all P > 0.05), but the specificity of 18 F-FAPI-42 PET was significantly higher than that of CE-MRI (47.06% vs 11.76%, P = 0.031). The semiquantitative analysis of PET parameters showed that SUVmax and TBR of 18 F-FAPI-42 PET and 11 C-MET PET in glioma recurrence were significantly higher than treatment-related changes (all P < 0.05). The diagnostic performance of 18 F-FAPI-42 PET TBR is outstanding (AUC: 0.940), higher than 11 C-MET SUVmax and TBR (AUC: 0.842 and 0.851, P = 0.099 and 0.080), and significantly better than 18 F-FAPI-42 SUVmax (AUC: 0.668, P < 0.001).

Conclusions: The diagnostic efficacy of 18 F-FAPI-42 PET for glioma recurrence is comparable to 11 C-MET PET, and its specificity superior to CE-MRI. 18 F-FAPI-42 PET has a high TBR and advantages in delineating glioma boundaries, which may provide valuable information for therapeutic decision-making.

Background: Multiple system atrophy (MSA) is a progressive neurodegenerative disorder with heterogeneous subtypes, including cerebellar (MSA-C) and parkinsonian (MSA-P). Dual-tracer PET imaging using 18F FDG and dopamine transporter (DAT) scans provides pathophysiologic insight but poses limitations in cost and resources. Dual-phase 18F FP-CIT PET offers an alternative by capturing perfusion-like and DAT signals in a single scan.

Objective: To evaluate the diagnostic and phenotypic utility of dual-phase 18F FP-CIT PET in early-stage MSA.

Methods: We retrospectively studied 39 patients with clinically established MSA who underwent dual-phase 18F FP-CIT PET within 2 years of symptom onset. Early-phase (0-10 min) images assessed perfusion-like uptake, and delayed-phase (90 min) images measured DAT uptake. PET patterns were visually classified as normal, presynaptic, or trans-synaptic based on DAT and putamen perfusion in the early phase, and compared across clinical subtypes, putaminal 3T MRI findings (DWI and SWI), and clinical severity. In addition, regional SUVR was compared across MSA subtypes and clinical severity.

Results: Striatal PET patterns differed by subtype (P<0.001): Trans-synaptic pattern was predominant in MSA-P, while normal and presynaptic patterns were more common in MSA-C. MRI abnormalities in the putamen were present in all patients with abnormal putamen on early PET, but also in 58% of patients with normal PET. Early- and delayed-phase striatal SUVRs correlated inversely with UPDRS part III scores (P<0.001). Asymmetry of cerebellar perfusion on early PET was significantly elevated in MSA-C compared with MSA-P (P<0.001). Levodopa responsiveness was most frequent in patients with trans-synaptic PET patterns.

Conclusions: Dual-phase 18F FP-CIT PET provides a single-session approach for capturing both perfusion and DAT status, enabling subtype classification and disease severity assessment in early MSA. Putaminal abnormality on early FP-CIT PET might be less sensitive than MRI, and asymmetric cerebellar perfusion could be a useful marker for differential diagnosis of ataxia.

Immunohistochemistry (IHC) is routinely used to determine the estrogen receptor (ER) expression status of breast cancer. 18 F-fluoro-estradiol ( 18 F-FES) PET/CT is indicated for select breast cancer patients with ER+ breast cancer, and patients with tracer-avid disease typically enjoy favorable responses to endocrine therapy (ET). We present 2 patients with metastatic breast cancer that were ER+ on IHC but lacked tracer avidity on 18 F-FES PET/CT. We hypothesize that despite ER detection on IHC, these receptors were nonfunctional, lacking the ability to bind estrogen. Since functional ER is a prerequisite for response to ET, these patients are not likely to respond to ET.

The advent of CFTR modulators has marked a breakthrough in cystic fibrosis management. Current monitoring relies on clinical data, spirometry, and CT. We report the interest of functional assessment using ventilation/perfusion (V/Q) SPECT/CT with 99m Tc in 3 patients treated with Elexacaftor/Tezacaftor/Ivacaftor (ETI). Two patients exhibited improvement in lung function on SPECT imaging, consistent with their clinical response, which was more pronounced than the structural changes observed on CT. The third patient exhibited no scintigraphic improvement, consistent with no clinical benefit. These results suggest that, while CT reflects structural changes, V/Q SPECT/CT provides complementary information on regional lung function, enabling early detection of ETI response.

A 6-year-old girl with high-risk neuroblastoma underwent 123 I-MIBG scintigraphy for disease surveillance, revealing abnormal radiotracer uptake in a nodule located posterior to the right lobe of the thyroid. Retrospective evaluation of prior 123 I-MIBG imaging demonstrated gradual enlargement of this lesion, accompanied by increasing 123 I-MIBG accumulation over time. Surgical excision and pathologic examination confirmed ectopic thymic hyperplasia. This case illustrates that ectopic thymic hyperplasia can lead to false-positive 123 I-MIBG uptake in pediatric patients with neuroblastoma.

Sclerosing epithelioid fibrosarcoma is extremely rare and aggressive soft-tissue sarcoma. Here, we report the 68Ga-DOTA-IBA PET/CT findings in a case with sclerosing epithelioid fibrosarcoma with bone metastases. 68Ga-DOTA-IBA PET/CT revealed increased uptake of DOTA-IBA in bone metastases. Unexpectedly, 68Ga-DOTA-IBA uptake was also observed in the primary sclerosing epithelioid fibrosarcoma in the abdomen.

A 6-year-old boy presented with a 2-month history of fever of unknown origin. 18F-FDG PET/CT was performed to identify the potential source, revealing a solitary focus of abnormal radiotracer uptake in the left humerus. Bone marrow biopsy confirmed metastatic neuroblastoma. Subsequent 123I-MIBG SPECT/CT and 68Ga-DOTATATE PET/CT scans failed to detect a primary tumor site. This case illustrates that solitary humeral metastasis can occur in the absence of an identifiable primary neuroblastoma, even after comprehensive imaging with 3 different radiotracers: 18F-FDG, 123I-MIBG, and 68Ga-DOTATATE.

Background: To investigate newly diagnosed multiple myeloma (MM) patients and determine whether a combination of baseline [ 18 F]FDG-PET-derived parameters and clinical parameters would improve patient prognostication.

Patients and methods: In this IRB-approved study, patients who underwent [ 18 F]FDG-PET/CT as part of their initial diagnostic workup for MM in our centre between 2018 and 2024 were included. Various [ 18 F]FDG-PET/CT parameters were extracted, including bone marrow, focal lesion, and total body measurements. Also, clinical parameters were gathered. The Cox proportional model was employed to estimate hazard ratios (HRs) for each parameter. A P -value <0.05 was considered statistically significant.

Results: A total of 42 patients (mean age =67 y) entered this study. The median follow-up was 24 months. From continuous [ 18 F]FDG-PET/CT-derived parameters, total-body metabolic tumor volume (TMTV), total-body total lesion glycolysis (TTLG), and bone marrow SUVmax were found to be significantly correlated with patient survival. Following dichotomization, TMTV and TTLG lost their statistical significance, while bone marrow SUVmax retained its significance, showing an HR of 8.5 ( P = 0.039). Moreover, the presence of extramedullary disease was the other significant predictor of survival, with an HR of 5.5 ( P = 0.002). Among the continuous clinical parameters, serum free light chain ratio, β2-microglobulin, LDH, and creatinine levels significantly correlated with patient survival. Only serum β2-microglobulin retained its significance following dichotomization, showing an HR of 4.0 ( P = 0.015).

Conclusions: [ 18 F]FDG-PET/CT-derived parameters, particularly high bone marrow SUVmax and the presence of extramedullary disease, as well as their combination with clinical parameters, particularly high serum β2-microglobulin level, have the potential to enhance MM prognostication at the time of baseline staging.

Primary clear cell adenocarcinoma of the urethra (CCAU) is a rare malignant tumor in the female genitourinary tract and reported only in single case reports. Imaging examinations play an important role in preoperative localization and qualitative diagnosis; the final diagnosis relies on pathologic examination. We report here the MRI and FDG PET/CT findings of primary clear cell adenocarcinoma of the urethra in a female.