Indian Journal of Nuclear Medicine最新文献

Giardia lamblia is an intestinal protozoan with oral-fecal transmission. Infection is predominantly located in the small intestine. Giardiasis causes intraepithelial lymphocytosis in the small intestine which causes false-positive fluorodeoxyglucose (FDG) uptake mimicking malignancy. We present here an interesting image of fluorine-18 FDG positron emission tomography/computed tomography showing jejunal uptake caused by giardiasis in a known case of lymphoma.

Small cell carcinoma (SCC) of the kidney is included in extrapulmonary SCC which is a group of extremely rare but highly aggressive cancers. There have been only a few case reports and small retrospective series in the literature describing the malignancy in kidneys. Most of the published reports describe the entity as a variant mixed with other tumor subtypes such as urothelial carcinoma, adenocarcinoma, and squamous cell carcinoma. Pure-form SCC in kidneys is exceedingly rare. Fluorodeoxyglucose positron emission tomography-computed tomography plays an essential role in the accurate staging evaluation of this cancer.

Thyroid cancer is the most common endocrine malignant tumor and accounts for 1% of all cancers. Management of differentiated thyroid carcinoma is total thyroidectomy, followed by iodine-131 (I-131) radioactive iodine (RAI) therapy for thyroid remnant tissue. I-131 whole-body scan helps in the follow-up evaluation in remnant, residual, and recurrence cases. Principle of uptake of I-131 is through sodium-iodide symporter expression on the cells. Physiological uptake of iodine is usually seen in salivary glands and gastrointestinal tract, and false-positive uptakes are seen in lesions such as mucinous cystadenoma, struma ovarii, hepatic, renal, thymic, and meibomian cysts. Here, we present the review of literature of series of cases observed in our department presenting with false-positive uptake of RAI in vertebral hemangioma, lipoma, sinusitis, teratoma, and uterine leiomyoma.

A 21-year-old male with embryonal rhabdomyosarcoma of the prostate was referred for ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) and ⁶⁸Ga-prostate-specific membrane antigen (PSMA) PET/CT for initial disease staging. The PET scans revealed hypermetabolic and PSMA expressing lobulated mass involving both lobes of the prostate and weakly metabolic and PSMA expressing few bilateral pararectal and external iliac nodes, multiple bilateral lung nodules scattered over the lung parenchyma and multiple bone marrow lesions in both axial and appendicular skeleton. Magnetic resonance imaging prostate showed gross prostatomegaly with large lobulated T2 hyperintense heterogeneously enhancing mass lesion showing restricted diffusion, involving both lobes of the prostate with extraprostatic spread along anterior, posterior, and left lateral margins with evidence of lymph nodal and osseous metastases. The demonstration of increased uptake of ¹⁸F-FDG and ⁶⁸Ga-PSMA in the primary as well as bilateral pararectal and external iliac nodes, multiple bilateral lung nodules, and multiple bone marrow lesions in both axial and appendicular skeleton indicates a potential role of ¹⁸F-FDG PET/CT and ⁶⁸Ga-PSMA PET/CT in disease staging in this rare aggressive tumor of the prostate.

Purpose of the study: The primary objective was to establish the reference values for small-bowel and colonic transit within the context of the routine standard solid meal gastric emptying scintigraphy (GES). The secondary objective was to compare the small-bowel and colonic transit between the anterior view and geometric mean methods.

Materials and methods: Twenty-nine healthy controls underwent routine GES, with additional imaging at 24 h if feasible. Small-bowel transit was assessed using the index of small-bowel transit (ISBT), calculated as the ratio of terminal ileal reservoir counts to total abdominal counts at 4 h. Colonic transit was evaluated using the colonic geometric center (CGC) by dividing the large bowel into four segments, with an additional fifth segment accounting for the eliminated counts. Reference values were established based on the fifth percentile or mean ± 1.96 standard deviations. Rapid small-bowel transit was visually determined. Paired Samples t-test or Wilcoxon signed-rank test, as applicable, was used to compare the small-bowel and colonic transit between the anterior view and geometric mean methods. For comparing small-bowel and colonic transit between females and males, the Independent samples t-test or Mann-Whitney U-test was applied, as appropriate. The correlation between age and small-bowel and colonic transit was assessed using Spearman's rank correlation analysis.

Results: The reference value for small-bowel transit using the geometric mean method was established as ISBT >37% at 4 h, whereas rapid small-bowel transit was defined as the first visualization of activity in the cecum-ascending colon within 2 h. For colonic transit, the reference range was established as CGC 2.8-4.4 at 24 h. Comparing the anterior view and geometric mean methods, there were no significant differences in ISBT and CGC values (P ≥ 0.125). Gender did not affect small-bowel and colonic transit in both methods (P ≥ 0.378), and age showed no significant correlations (P ≥ 0.053).

Conclusion: This study determined the reference values for small-bowel and colonic transit in the Indian population using routine GES, avoiding the need for additional complex procedures. The results may be generalized to the Indian population, emphasizing the importance of assessing small-bowel and colonic transit in patients with normal gastric emptying parameters to enhance gastrointestinal transit evaluation.

Purpose: The purpose of this study is to evaluate the adenosine pharmacological stress-induced electrocardiogram (ECG) changes and their association with stress-induced ischemic defects on myocardial perfusion scintigraphy (MPS) in the evaluation of coronary artery disease (CAD) and to evaluate event-free survival among patients with positive and negative ECG/MPS image findings.

Methods: A total of 100 patients were examined using stress MPS from March 2020 to August 2021. Stress-induced ECG changes during adenosine infusion were evaluated. The summed stress score (SSS) was evaluated to identify ischemic defects in myocardium. Association of stress ECG changes and scintigraphic results was evaluated.

Results: Out of 100 patients, stress ECG changes during adenosine infusion were seen among 34 patients, whereas 66 patients had normal ECG findings. Positive stress MPS findings with SSS >3 were seen in 22 patients, whereas 78 patients had SSS ≤3. There was no agreement between stress ECG changes and MPS findings with Cohen's kappa coefficient (κ) = -0.023, whereas there was mild agreement between stress ECG changes and SSS >7 with κ = 0.105. Median follow-up of 11 months showed more events among patients with positive ECG changes than negative ECG changes.

Conclusion: Adenosine, pharmacological stress is safe to use, but few patients might experience some minor and transient symptoms. Adenosine may induce ECG changes in patients with or without positive MPS findings. Patients with concordant positive findings need aggressive cardiac care, whereas patients with small or no defects on MPS need close monitoring.

Prostate cancer is the most common solid organ tumor in men and has been reported to metastasize to unusual sites such as the epididymis. The clinical standard for detecting recurrent disease is through positive emission tomography/computed tomography with the radiotracer ¹⁸F-DCFPyL binding prostate-specific membrane antigen (PSMA) expressed by cancerous cells. Although PSMA can also be expressed physiologically, metastases are more likely to be intensely PSMA expressing and in a typical distribution depending on the extent of disease burden in the individual patient. A MEDLINE search revealed only three other case reports of isolated epididymal metastases from prostate cancer diagnosed with prostate-specific membrane antigen positron emission tomography-computed tomography. This case series comprising both metastatic and physiological PSMA expression in the epididymis provides a useful framework for the interpreting physician when the possibility of this rare but important finding is encountered in prostate cancer imaging.