Indian Journal of Nuclear Medicine最新文献

Background: Langerhans cell histiocytosis (LCH), a rare hematological disorder, presents significant diagnostic challenges due to its varied clinical manifestations. This study aims to analyse the use of F-18 fluoro-deoxy-glucose positron emission tomography computed tomography (F-18 FDG PET/CT) in diagnosis, staging, and management of LCH.

Materials and methods: Fifty-nine patients with LCH were included, who underwent a total of ninety-three F-18 FDG PET/CT scans (including follow-up scans in 19 patients). The sites of abnormal FDG uptake were assessed and the maximum standardized uptake value was measured in all the scans.

Results: Twenty-five patients (42.4%) had single system LCH (SS-LCH) and 34 patients (57.6%) had multisystem involvement LCH, 49/59. The most common sites of LCH involvement were bones (49/59, 83.1%) and lymph nodes (39/59, 44.9%). 12/59 patients (20.3%) had unifocal SS-LCH bone lesions, mostly in skull. The other common sites involved were lungs, liver, spleen, marrow, skin, and soft tissues. Less commonly involved sites included pancreas (2 cases), occipital lobe (1 case), and bowel (1 case). PET/CT was used in response assessment in 19 patients and helped in initiation of second line chemotherapy in cases of disease progression (2 cases) and relapse (2 cases). Seven cases with clinical suspicion were diagnosed as LCH based on lesion characteristics and FDG uptake, which were later biopsy proven.

Conclusion: F-18 FDG PET/CT revealed morphological and metabolic characteristics of LCH lesions, aiding in accurate diagnosis, assessment of disease burden, and prognostication, thereby can be used as a comprehensive imaging tool in management of LCH.

We present the case of a 36-year-old woman with papillary thyroid cancer (PTC) who had undergone thyroidectomy and nodal dissection. In addition to thyroid remnant and nodal metastases, initial postoperative radioiodine (RAI) diagnostic whole-body scintigraphy showed abnormal diffusely increased linear band-like uptake in the thorax corresponding to the esophageal contour, raising suspicion of lower esophageal obstruction. Retrospective inquiry revealed a history of long-standing, progressive dysphagia. Findings of computed tomography, barium swallow study, and esophageal manometry were consistent with achalasia cardia. She underwent high-dose RAI therapy for PTC and laparoscopic cardio-myotomy for achalasia cardia. This case report aims to familiarize nuclear medicine physicians with the appearance of achalasia cardia on RAI scintigraphy, which may mask surrounding lymph nodal or vertebral metastases. Such a finding when encountered should also prompt further work-up and appropriate management.

Rosai-Dorfman-Destombes (RDD) disease is also called as sinus histiocytosis and is characterized by enlarged lymph nodes and previously called as non-Langerhans cell histiocytosis. Based on pathologic, molecular, and genetic features, RDD disease has been classified into sporadic noncutaneous (classical nodal, extranodal, neoplasia associated, and autoimmune associated), familial (H syndrome, autoimmune lymphoproliferative syndrome related, and familial NOS), and cutaneous subtypes. Cutaneous RDD disease is not associated with lymphadenopathy or visceral organ involvement. The disease is usually localized and has relatively better long-term prognosis. Presented here is a case of indurated plaque-like skin lesions over the abdomen. ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography scan revealed FDG avid cutaneous-subcutaneous soft-tissue lesions. Histology confirmed the diagnosis of cutaneous RDD disease.

White adipose tissue (WAT) generally has negligible glucose utilization and thus, shows no or insignificant Fluorine-18 fluoro D-glucose (FDG) uptake. However, corticosteroids can cause altered biodistribution of FDG with increased uptake in WAT. We hereby describe a case of immune complex-mediated glomerulonephritis showing diffusely increased FDG uptake in WAT secondary to high-dose corticosteroid therapy.

Purpose: In this study, we aimed to reveal the incidence of ≥3 focal lesions (FLs) and analyze overall survival (OS) and progression-free survival (PFS) according to the number of FLs, as well as to identify mortality and PFS risk factors, in our newly diagnosed multiple myeloma (NDMM) patients.

Materials and methods: A total of 89 NDMM patients who underwent ¹⁸F-FDG positron emission tomography/computerized tomography (PET/CT) imaging were included in the study.

Results: While 57.3% of the patients had ≥3 FLs, 20.2% had no FL. The median OS and PFS were 55 and 43 months, respectively. The median survival time was 49 months for patients with ≥3 FLs and 101 months for patients with <3 FLs, with a statistically significant difference (P = 0.049). The median PFS was 34 months in patients with ≥3 FLs and 67 months in patients with <3 FLs; this difference was also statistically significant (P = 0.026). The difference in median survival was statistically significant, based on whether autologous stem cell transplantation (ASCT) was performed and the number of FLs (≥3 or <3) (P = 0.011). In the multivariate regression analysis, ≥3 FLs was not a predictor of mortality but was a risk factor for PFS.

Conclusion: In our study, we observed significantly worse OS and PFS in patients with ≥3 FLs at diagnosis, and it is noteworthy that the OS was worse in those patients who did not undergo ASCT. ¹⁸F-FDG PET/CT is a feasible imaging technique for the prediction of prognosis in the initial evaluation of NDMM, and we believe that consolidation with ASCT as a modifiable factor, especially in patients with ≥3 FLs, will lead to a more favorable prognosis.

Background: Accurate staging of tumors is paramount in the management of cancer patients. Current noninvasive modalities like computed tomography (CT) and fluorodeoxyglucose positron emission tomography (FDG PET) scan offer viable approaches to stage the disease; however, the role of FDG PET-CT in gastric cancer remains unclear, in comparison to esophageal and gastroesophageal junction cancers, where they have proven usefulness.

Aim: The primary outcome was to assess the usefulness of FDG PET-CT in staging gastric cancer in our population. The secondary outcome was to compare the positive yield of PET-CT with staging laparoscopy and avidity of FDG PET-CT scan in gastric cancer.

Materials and methods: In our institution, FDG PET-CT is routinely used in staging gastric cancer, where CT scan does not show metastases. We did a retrospective analysis of data of gastric cancer patients, who were not known to have metastatic disease, who underwent pretreatment staging workup at our institute between January 2018 and December 2022. Tumor and lymph node (LN) avidity and their association with Lauren classification was assessed. Multivariate regression analysis for factors associated with metastases on FDG PET-CT scan with tumor size, nodal status, and node avidity was also assessed. Data were analyzed using SPSS version 26 for descriptive and comparative statistics; multivariate regression analysis was performed to identify factors affecting the diagnosis of metastases on PET-CT. P =0.05 was considered statistically significant.

Results: Tumor avidity was shown in 181 (89.16%) patients, and LN avidity in 80 (39.4%) patients. This was independent of the Lauren classification. In addition, previously unidentified metastases were highlighted in 16 (8%) patients. Multivariate regression analysis for factors associated with metastases on FDG PET-CT scan showed a significant association with tumor size (P < 0.001), nodal status (P = 0.005), and node avidity (P = 0.024).

Conclusions: FDG PET-CT scan can identify an additional 8% of previously unidentified metastases, thereby playing a useful role in the staging workup of advanced gastric cancer patients. Approximately 90% of gastric cancers and 40% of LNs were PET avid in our population.

Detection of adrenal lesions either incidentally, or in symptomatic cases and/or during staging/restaging of oncological cases, it is very crucial to know the adrenal lesion is benign or malignant. Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET/CT) helps in this comprehensive evaluating process. Here, we present the most frequently facing adrenal lesions in routine oncological PET/CT scans. The aim of this presentation is to know the FDG uptake spectrum of various adrenal lesions on PET/CT scan so that increase the diagnostic accuracy and spectrum of differential diagnosis.

Fibroblast activation protein (FAP) is a quinoline-based membrane bound glycoprotein enzyme. It is not expressed in normal adult tissue except for the myometrium and sometimes in pancreas. The expression increases in inflammation and in cancer-associated fibroblasts. Gallium 68-FAP inhibitor (FAPI) is known to localize in various neoplasms by the virtue of their property of cancer-associated fibroblast activity. Fibroblasts are also known to be associated in inflammatory and infectious condition such as cholecystitis, pyelonephritis, and tuberculosis. Immunoglobulin G4 related disease (IgG4RD) is characterized by infiltration of various tissues with IgG4-rich lymphoplasmacytic fibrotic tissue and has been reported to express cancer-associated fibroblast. The time-tested molecule for cancer imaging F18-fluorode-oxyglucose requires 4-6 h of fasting state. Ga68-FAPI does not require fasting. This pictorial essay illustrates various entities, cancerous as well as noncancerous using Ga68-FAPI positron emission tomography computed tomography (PET CT) imaging.