Indian Journal of Nuclear Medicine最新文献

Parasitic leiomyoma is a rare late complication of laparoscopic morcellation done for a symptomatic uterine fibroid. We present here a case of symptomatic multiple parasitic leiomyomas in a 35-year-old woman who had undergone laparoscopic morcellation for infertility. Abdominal wall tumor raised suspicion of malignancy, for which ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography was performed, which demonstrated multiple parasitic leiomyomas, confirmed with post-surgical histopathology.

Introduction: Brown adipose tissue (BAT) is crucial for thermogenesis and energy expenditure. This study examines the demographic, environmental, and clinical factors influencing brown fat fluorodeoxyglucose (FDG) uptake, particularly in relation to its anatomical distribution, body mass index (BMI), gender, and temperature.

Methods: Data from 139 participants were analyzed, documenting demographics, BMI, weight, and environmental temperatures. FDG uptake by BAT at various anatomical sites was assessed using positron emission tomography/computed tomography scans. Statistical analyses, including Chi-square tests, Fisher's exact tests, and Mann-Whitney U-tests, were conducted to explore the associations between BAT uptake and the variables of interest.

Results: Lower external temperatures were associated with increased BAT uptake at perivascular, periviscus, and solid organ sites. Meanwhile, higher ambient room temperatures were linked with increased uptake at these same sites, possibly due to contrast with the cold external environment during winter.

Conclusion: Our findings highlight the significant influence of gender and environmental temperatures on BAT uptake. The thermogenic role of BAT in colder conditions underscores its metabolic significance. Further research is needed to explore the underlying mechanisms of these associations and their potential implications for metabolic health interventions.

Stress myocardial perfusion imaging (MPI) is a commonly performed imaging to detect stress-induced perfusion defects. However, it can, at times, detect incidental ominous pathologies such as breast cancer, lung cancer, plasmacytoma, or multiple myeloma. Here, we report the case of a 54-year-old man incidentally detected to have plasmacytoma on ^99mTc-Sestamibi (2-methoxyisobutylisonitrile) MPI.

Background: In gamma cameras, there is significant interest in developing novel devices that employ a semiconductor detector. The most significant quality control parameter for assessing the performance of gamma cameras with parallel-hole collimating is the spatial resolution. Acceptable spatial resolution is due to the high absorption and stopping power of collimator materials, while they may lead to a reduction in sensitivity in the same condition. Thus, a comparison between sensitivity and spatial resolution is crucial in nuclear medicine imaging devices.

Aims and objectives: This work aimed to compare spatial resolutions using pixellated parallel-hole collimators with lead and tungsten at equal sensitivity to assess the camera's performance.

Materials and methods: The overall imaging system was simulated using a Geant4 Application for Tomographic Emission simulation tool. Furthermore, source-to-detector distance effects on image performance and spatial resolution were evaluated using a simulated hot-rod phantom. The full width at half maximum (FWHM) and the full width at tenth maximum (FWTM) stand for the spatial resolution.

Results: The averages of measured FWHM using lead at equivalent sensitivities were 3.28% greater than that of tungsten. Furthermore, the averages of measured FWTM of lead at equivalent sensitivities were 7.99% greater than those obtained with tungsten.

Conclusion: The results demonstrated that at a specific sensitivity, lead provides better spatial resolution than tungsten.

Extracardiac images are occasionally revealed on Tc-99m tetrofosmin single photon emission computed tomography-computed tomography (SPECT-CT) imaging due to the known oncotropic properties of the tracer. A large area of inhomogeneous tracer uptake was revealed on SPECT-myocardial perfusion imaging in a 59-year-old male patient referred to our department for suspected coronary artery disease. On subsequent SPECT-CT, the mass was located in the anterior mediastinum, characterized by regular margins not infiltrating the adjacent anatomical structures, and had diameters of 6 cm × 5.2 cm × 10.3 cm. A very high uptake ratio value, equal to 26, strengthened the suspicion of giant thymoma. However, an ultrasound (US)-guided transcutaneous core biopsy was deemed necessary before surgical removal of the lesion due to its extremely large size and the absence of associated paraneoplastic syndromes. In this aspect, the SPECT-CT imaging proved to be very useful in guiding the sampling procedure in an area rich in viable cells, due to the presence of multiple areas of necrosis of various sizes that could have affected the outcome of the US-guided core biopsy.

Appendiceal adenocarcinomas are rare invasive gastrointestinal neoplasms, with higher propensity to metastasize to lymph nodes and peritoneum, whereas other common sites include liver and lung. Metastases to the breast are exceptionally rare in appendiceal neoplasms, with limited data in literature. We present the case of a recurrent mucinous adenocarcinoma of the appendix with clinically occult breast, skeletal, and nonregional nodal metastases detected on fluorine-18-fluorodeoxyglucose positron emission tomography-computed tomography scan.

Parathyroid ectopia may occur in various anatomical regions and is caused by abnormal embryological migration of the parathyroid glands. Ectopic parathyroid adenomas account for 6%-16% of cases of primary hyperparathyroidism. We present the case of a mediastinal ectopic adenoma detected on myocardial perfusion imaging with 99m Technetium (99mTc)-tetrofosmin in a 64-year-old patient. Incidental extracardiac 99mTc-tetrofosmin uptake in mediastinal ectopic parathyroid adenomas has been rarely reported in the literature. Our case is rare as it represents a small proportion of all ectopic parathyroid adenomas.

Penile squamous cell carcinoma (PSCC) is an uncommon malignancy in males, often associated with a poor prognosis following metastatic dissemination. We report the case of a 46-year-old male who presented with a rare and extensive metastatic profile of PSCC, as detected by ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography following penectomy. The scan demonstrated extensive hypermetabolic metastatic involvement, including bilateral inguinal and external iliac lymph nodes, multiple lytic osseous metastases, and diffuse peritoneal carcinomatosis, the latter presenting in the form of peritoneal superscan. In addition, skeletal metastases extended below the knees, affecting both tibiae - an atypical metastatic site for PSCC. Despite the aggressive molecular imaging findings, the patient opted against further therapeutic interventions and succumbed to the disease 45 days later at home, highlighting the fulminant and disseminated nature of this malignancy.

Background: While ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) remains the gold standard for staging diffuse large B-cell lymphoma (DLBCL), it is limited by nonspecific uptake and physiological artifacts. This study explores the potential of the novel C-X-C chemokine receptor type 4 (CXCR4)-targeted tracer ⁶⁸Ga-Pentixafor as a complementary receptor-specific imaging modality.

Methods: In this prospective single-center study, 27 treatment-naïve patients with histopathologically confirmed DLBCL underwent ⁶⁸Ga-Pentixafor and ¹⁸F-FDG PET/CT within a 2-week interval. Lesion detection, Lugano staging concordance, and maximum standardized uptake value (SUVmax) were assessed and compared using Cohen's kappa for agreement and paired t-tests for quantitative variables.

Results: ⁶⁸Ga-Pentixafor PET/CT showed near-perfect agreement with ¹⁸F-FDG PET/CT for extranodal lesion detection (κ =0.926, P < 0.001). For nodal lesions, substantial agreement was observed (κ =0.804, P < 0.0001). Lugano staging results were consistent between both modalities in 92.6% of cases (25/27), with only two instances of discordance. Importantly, ⁶⁸Ga-Pentixafor detected biopsy-confirmed bone marrow involvement in four cases missed by ¹⁸F-FDG. Although ¹⁸F-FDG showed higher SUVmax values for nodal lesions (15.2 ± 7.6 vs. 8.4 ± 4.2; P < 0.001), there was no significant difference in uptake for extranodal sites. Subgroup analysis indicated a nonsignificant trend toward higher CXCR4 expression in the nongerminal center B-cell (non-GCB) subtype compared to the GCB subtype (P = 0.665). Notably, gastrointestinal artifacts associated with metformin use were absent on ⁶⁸Ga-Pentixafor scans.

Conclusion: This first-of-its-kind study in a uniform cohort of newly diagnosed DLBCL patients demonstrates that ⁶⁸Ga-Pentixafor PET/CT shows high concordance with ¹⁸F-FDG PET/CT, with superior detection in the bone marrow and reduced physiological background. Its receptor-specific targeting of CXCR4 facilitates accurate disease assessment and provides a noninvasive approach to evaluate therapeutic targets, supporting its potential role in personalized CXCR4-directed theranostic strategies.

This article discusses the role of various imaging modalities in diagnosing and managing surgical renal conditions in pediatric patients. It emphasizes the importance of tailored surgical interventions based on accurate imaging assessments. The cases presented cover a range of conditions, including pelvic-ureteric junction obstruction, vesicoureteric reflux, congenital renal anomalies, and postoperative management. The article underscores the pivotal role of various imaging modalities in diagnosing and managing a spectrum of surgical renal conditions in pediatric patients, providing valuable insights for clinical decision-making.