Clinical Nuclear Medicine最新文献

Takayasu arteritis (TAK) is a large-vessel vasculitis characterized by granulomatous inflammation of the aorta and its primary branches. The clinical presentation of TAK is heterogeneous. Intracranial vascular involvement in TAK is uncommon and is understudied. Clinical, biochemical, and imaging data always do not correspond, making it difficult to evaluate disease activity in TAK. FAPI PET/CT is a noninvasive whole-body imaging modality that could potentially aid in diagnosis, therapy monitoring, and identifying disease relapse when 18 F-FDG-PET/CT is inconclusive. The authors in this research demonstrate intracranial and extracranial vascular involvement in a patient of TAK on 68 Ga-FAPI-04 PET/CT.

Neuroendocrine prostate cancer (NEPC) is an aggressive subtype of prostate cancer, often developing from androgen receptor (AR) independence, characterized by neuroendocrine molecular markers and nonresponsiveness to standard treatments of prostate adenocarcinoma. The evolution of adenocarcinoma to NEPC is characterized by epigenetic changes, leading to the downregulation of the PSMA transmembrane protein, as well as the upregulation of FDG-uptake pathways and somatostatin receptor expression. We present a case of NEPC that depicts a significant metastatic intertumoral heterogeneity as depicted on PSMA, FDG, and DOTATATE PET/CT scans. Such multiprobe PET evaluation of NEPC may assist in sampling the most aggressive disease and guide an appropriate management strategy. It also provides a cellular-level insight into this dreadful disease with very limited treatment options.

We report a thyroid-shaped iodine uptake in the scrotum incidentally detected on an 131 I whole-body scan (WBS). A 62-year-old man with papillary thyroid carcinoma underwent 131 I ablation therapy after total thyroidectomy. A postablation whole-body scan after 7 days revealed a butterfly-shaped uptake in the lower pelvic region on the anterior image, which was suspected to be an unusual form of urinary contamination. However, additional lateral images demonstrated that the tracer activity was not superficial. Computed tomography revealed a bilateral scrotal hydrocele that corresponded to the 131 I uptake in the lower pelvis on WBS. This case presents a previously unreported hydrocele incidentally detected on 131 I WBS, with iodine uptake in the bilateral scrotal regions, shaped like a thyroid gland.

A 68-year-old man with a history of 2 primary tumors (prostate adenocarcinoma and colon adenocarcinoma) underwent 18 F-DCFPyL PET/CT for biochemical recurrence after prostate cancer treatment. A hypogastric nodular lesion with avid PSMA uptake was observed, interpreted as a possible implant. Surgical excision revealed a benign spindle cell proliferation compatible with a desmoid tumor (fibromatosis). This case highlights the potential pitfall of desmoid tumors mimicking malignancy on 18 F-DCFPyL PET/CT, emphasizing the importance of awareness and correlation with clinical and histopathologic findings.

A 70-year-old man with primary hyperparathyroidism underwent 18F-choline PET/CT to localize a parathyroid adenoma before surgery. 18F-choline PET/CT confirmed the right superior parathyroid adenoma but also revealed skin uptake corresponding to an inflammatory epidermoid cyst of the left neck. Two months later, the patient underwent successful minimally invasive parathyroidectomy. The epidermoid cyst was also excised. Inflammatory epidermoid cysts can be a cause of false-positive 18F-choline skin uptake.

Purpose: Primary hyperparathyroidism is one of the most common endocrine disorders and it is only curable by surgery. This study aimed to accurately localize parathyroid adenomas (PTAs) in patients with negative results from conventional diagnostics, consisting of MIBI SPECT/CT and ultrasound, by utilizing F-18-ethylcholine-PET/ultrasound real-time fusion imaging. Fusion ultrasound is a well-established diagnostic tool that enables precise identification and localization of target structures by superimposing MRI, CT, or PET/CT with real-time B-mode ultrasound. The goal was to detect occult PTAs and enable curative targeted parathyroidectomy.

Methods: A total of 49 patients with primary hyperparathyroidism were consecutively recruited from routine clinical workflows. Given negative standard diagnostics, patients were referred for FEC-PET/CT followed by FEC-PET/ultrasound. PTAs were categorized as positive, ambiguous, or negative based on FEC-PET/ultrasound findings. A retrospective data analysis was performed, examining PTA volume (ml) based on ultrasound results, SUVmax of PTAs and locoregional lymph nodes, as well as parathyroid hormone, calcium, and phosphate levels. Maximal, minimal, median, mean values, and SDs were reported.

Results: Forty-nine PTAs were identified, of which 45 were solitary, whereas 2 patients had double adenomas each. The study showed relatively high rates of ectopic PTAs (28%). No significant differences were observed in FUS-based detection rates between ectopic and orthotopic lesions. PTAs, exhibited significantly higher ( P <0.05) tracer uptake [SUVmax 4.5±2.7 (4, 1.4-11.9)] compared with lymph nodes [SUVmax 2.7±1.7 (2.5, 1.2-11.8)]. SUVmax was significantly higher in positive lesions compared with ambiguous cases ( P <0.05). No significant SUVmax difference was found for lymph nodes in ambiguous cases. FUS-based PTA volume ranged from 0.2 to 2.6 ml (mean 0.5±0.5 ml). Twenty-seven patients underwent surgery, and the diagnosis was confirmed in 90% of cases.

Conclusions: This study shows that FEC-PET/ultrasound offers valuable support for preoperative localization and thus can be considered as an effective and precise method for detecting parathyroid adenomas in primary hyperparathyroidism. Because of its high time and technical demands, it is reserved for challenging cases unresolved by standard diagnostics. Future technical advances may increase its accessibility.

We describe a case of a 76-year-old man with genetically confirmed hereditary transthyretin amyloidosis (hATTR) due to a pathogenic TTR variant, c.97_99dup (p.Met33dup), with possible coexisting amyloid light-chain (AL) amyloidosis. Serial Technetium-99m 2,3-dicarboxypropane-1,1-diphosphonate Tc-99m DPD) scintigraphy revealed persistent grade 3 myocardial uptake but minimal extracardiac tracer accumulation in the skeletal system and intestines. Despite similar or higher heart-to-contralateral (H/CL) ratios, other patients did not exhibit this pattern, underscoring the atypical nature of the observed findings in this case. This case highlights a rare myocardial-predominant uptake phenotype, which may offer insight into the distribution of bone-avid tracers in cardiac amyloidosis.

A 66-year-old man with end-stage kidney disease status post kidney transplantation underwent 99m Tc-MAG3 renal scintigraphy for evaluation of suspected urine leak. Initial dynamic images demonstrated severely impaired renal function of the graft without evidence of leak. On delayed planar images, radiotracer activity adjacent to the transplanted kidney was seen, which was then identified in the ostomy bag on SPECT/CT, representing hepatic excretion of 99m Tc-MAG3 in the setting of severe renal dysfunction. The findings on planar images may mimic a urinary leak. SPECT/CT is valuable in such cases, as it enables accurate anatomic localization and prevents misinterpretation.

A 74-year-old man with a history of monoclonal gammopathy of undetermined significance (MGUS) underwent surveillance whole-body 18 F-FDG PET 2 weeks before MRI-guided high-intensity focused ultrasound (MRgHIFU) of the left dentato-rubro-thalamic tract (DRTT) for his right-hand dominant, debilitating essential tremor. This baseline FDG PET showed normal thalamic metabolism. At 12 months post-treatment, FDG PET scan revealed a small focus of left thalamic hypometabolism, which corresponded to the left DRTT ablation area seen on post-treatment MRI. The patient was tremor-free in his right hand at 1-year follow-up. This case documents the chronic effects of MRgHIFU on cerebral FDG metabolism.

In primary hyperparathyroidism (PHPT), exact preoperative localization of parathyroid adenomas is essential for best surgical planning. While new PET tracers like 18 F-fluorocholine and 68 Ga-Trivehexin show promise, traditional imaging consists of 99m Tc-Sestamibi scintigraphy, SPECT/CT, and 4DCT. Herein, we report the potential new application of another angiogenesis imaging agent, 68 Ga-NODAGA-RGD PET/CT, illustrated in a 12-year-old girl with PHPT. The scan revealed diffuse skeletal tracer uptake (superscan) in addition to localizing right inferior parathyroid adenoma, thereby indicating systemic effects. This case underscores 68 Ga-RGD PET/CT as a possible instrument for parathyroid imaging and systemic evaluation, justifying more research to define its diagnostic value and role in treatment response evaluation.