Indian Journal of Nuclear Medicine最新文献

Lymphoscintigraphy is an established modality for imaging the lymphatic system using radiocolloids and is routinely indicated to find the cause of limb lymphedema. However, in this case series, we are highlighting other less-known indications of lymphoscintigraphy like chylothorax and chyluria which present as lymphatic leaks in the thorax and abdomen, respectively. Once the site of the lymphatic leak is established by lymphoscintigraphy, definitive management like thoracic duct ligation or sclerotherapy can be done. The other indication discussed is postrenal transplant perinephric fluid collection which can be challenging to confirm whether it is urinoma, lymphocele, or any other collection. And finally, sentinel lymph node localization is another, now, well-established indication of lymphoscintigraphy.

Role of FDG PET/CT in evaluation of biliary tract diseases remains relatively unexplored. PET/CT with FDG helps in evaluation of both infective / inflammatory as well as neoplastic diseases as increased glucose utilization is observed in both the conditions. In this article, we describe the spectrum of FDG PET/CT findings in various diseases affecting the biliary tract. Role of FDG PET/CT in neoplastic diseases involving the biliary duct has been described at the time of staging and response evaluation; in characterization of the intrahepatic mass (abscess v/s cholangiocarcinoma). In addition, we have discussed about the false positive FDG uptake along the biliary duct stent, which interfere with scan interpretation. Few of the benign conditions described are Langerhans cell histiocytosis and IgG4 related disease involving the biliary duct and adenomyomatosis and Xanthogranulomatous cholecystitis involving the gall bladder.

Neuroblastoma presenting with multiple muscles and subcutaneous tissue metastases is rarely reported in the literature. We would like to highlight such infrequent occurrences for increasing the clinical acumen of the medical fraternity with an aim to deliver proper therapy to patients.

We present a rare case of mediastinal capillary hemangioma in a 54-year-old female. She presented with back pain in the left suprascapular region, and the chest radiograph revealed left pleural effusion. On further workup with high-resolution computed tomography (CT) chest, a hypervascular pleural-based neoplastic lesion in the left upper hemithorax with gross left pleural effusion and subtotal collapse of the left lung was identified. ¹⁸F-fluorodeoxyglucose positron emission tomography/CT was suggestive of a weakly metabolic well-defined pleural-based soft tissue lesion in the left upper hemithorax along the mediastinal side. Neuroendocrine tumor was suspected. ⁶⁸Ga-DOTATATE PET/CT was advised, which showed intense uptake in the lesion. The mass was resected completely. Histopathological examination established the final diagnosis as benign vascular tumor consistent with a capillary hemangioma.

White thyroid scintigraphy corresponds to an absence or near-absence of radiotracer fixation in the cervical region. After eliminating technical causes, the main etiologies are iodine overload, thyroiditis, and congenital hypothyroidism. We report the case of a 22-day-old newborn with congenital hypothyroidism. As part of the etiological assessment, a cervical ultrasound was performed and showed a normal echostructured thyroid gland with no detectable lesions or vascular anomalies. On the other hand, a Tc 99m thyroid scintigraphy was also performed and revealed a lack of radiotracer uptake in the thyroid area in favor of a white thyroid scintigraphy. Congenital hypothyroidism is the main cause of mental retardation. Thyroid scintigraphy plays an important role in the etiological diagnosis of congenital hypothyroidism. A white thyroid scan and a thyroid in place on cervical ultrasound point to iodine transporter deficiency caused by sodium/iodide symporter gene mutations.

Introduction: Cholescintigraphy using Tc-99m Mebrofenin is routinely performed as an initial diagnostic test in infants with neonatal cholestasis suspected of having biliary atresia. Demonstration of drainage of bile into the small intestine indicates patency of the biliary tract and thus rules out biliary atresia. Non-excretion of tracer into the small intestine, however, can be caused by obstructive as well as non-obstructive conditions, and it is known that false-positive findings are found with the use of Tc-99m Mebrofenin scintigraphy.

Aim: In the present study, we retrospectively calculated the proportion of infants eventually diagnosed to have biliary atresia that were initially ruled to have a non-excreting cholescintigraphy pattern in our institution. We have also attempted a systematic description of the cardinal histological characteristics, haematological and hepatic biochemical variables in infants with non-excreting patterns.

Materials and methods: This retrospective, descriptive study was conducted in Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry. We reviewed data from infants who underwent cholescintigraphy with Tc-99m Mebrofenin between January 2016 through June 2022. We included infants in whom the scan was ruled "non-excreting" i.e. those infants in whom biliary atresia could not be ruled out based on the results of the scan. The difference in mean for haematological parameters and ALP were compared between the two groups i.e., biliary atresia versus other than biliary atresia by using Independent student's t-test; the remaining liver biochemical parameters were compared by using Mann-Whitney U Test and a p value < 0.05 was considered to be statistically significant.

Results: A non-excretory pattern on cholescintigraphy was found to be due to biliary atresia in 49% of cases (as confirmed by exploratory surgery) and an additional 19.6 % of cases by trucut biopsy (total 68.6%). The difference in the mean serum GGT levels was found to be statistically significant (<0.001).

Conclusion: A non-draining pattern on cholescintigraphy is caused by biliary atresia in the greater percentage of cases presenting with cholestasis. The difference in mean GGT levels was found to be statistically significant between biliary atresia and other causes of non-draining patterns on cholescintigraphy.

The technetium-99m ethylene dicysteine (Tc-99m EC) is a radiopharmaceutical used for renal scintigraphy, a noninvasive imaging technique that assesses kidney function as well as urinary tract obstruction. We describe the extrarenal Tc-99m EC uptake in a 70-year-old man with recurrent well-differentiated abdominal liposarcoma. In the present case, both liposarcoma lesions which were diagnosed by abdominal CT scan showed heterogeneous accumulation of the Tc-99m EC.

Large vessel vasculitis is a known but rare side effect of granulocyte colony-stimulating factor (G-CSF) therapy. We report a case of adenocarcinoma lung with pleural infiltration and mediastinal lymphadenopathy, who was treated with neoadjuvant chemotherapy and pegylated G-CSF. After three cycles, he developed a fever. He underwent F-18 fludeoxyglucose (FDG) positron emission tomography computed tomography for fever of unkwnown origin evaluation, which revealed a response to chemotherapy along with the appearance of FDG avid mural thickening in a few large arteries, suggesting a diagnosis of G-CSF-induced large vessel vasculitis.

Purpose: The blur introduced by breathing motion degrades the diagnostic accuracy of whole-body F-18 fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸F-FDG PET-CT) in lesions adjacent to the diaphragm by increasing the apparent size and by decreasing their metabolic activity. This study aims to evaluate the efficacy of motion correction by four-dimensional phase-based respiratory-gated (RG) ¹⁸F-FDG PET-CT in improving metabolic parameters of lesions adjacent to the diaphragm (especially in the lungs or liver).

Materials and methods: Eighteen patients with known lung or liver lesions underwent conventional ¹⁸F-FDG PET-CT and respiratory-gated PET-CT acquisition of the desired region using a pressure-sensing, phase-based respiratory-gating system. Maximum standardized uptake value (SUV_max), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were obtained for these lesions from gated and nongated PET-CT images for analysis. Furthermore, a visual analysis of lesions was done.

Statistics: Statistical significance of the RG image parameters was assessed by the two-tailed paired Student's t test and confirmed with the robust nonparametric Wilcoxon's signed-rank test (two-tailed asymptotic).

Results: There was an overall significant increase in SUV_max (P 0.001) in all gating methods with a percentage increase maximum of about 18.13%. On gating methods, MTV decreased significantly (P = 0.001) than that of nongating method (maximum reduction of about 32.9%). There was a significant difference (P = 0.02) in TLG between gated and nongated methods.

Conclusion: Motion correction with phase-based respiratory gating improves the diagnostic value of ¹⁸F-FDG PET-CT imaging for lung and liver lesions by more accurate delineation of the lesion volume and quantitation of SUV and can thus impact staging, diagnosis as well as management in selected patients.

Ga-68 labeled prostate-specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET/CT) is increasingly recognized as the best imaging modality for disease staging and detection of recurrent prostate cancer. Despite its name, PSMA expression has been reported in the neovasculature of several nonprostatic benign and malignant pathologies. Docetaxel, a taxane antineoplastic agent, is the mainstay of treatment in castration-resistant prostate cancer and high-volume hormone-sensitive prostate cancer. Although the occurrence of docetaxel-related interstitial lung disease is rare, it may lead to respiratory failure if treatment is delayed. We present a case of metastatic castration-resistant prostate cancer, wherein docetaxel-induced interstitial pneumonitis was detected on Ga-68 PSMA PET/CT after docetaxel administration.