Indian Journal of Nuclear Medicine最新文献

The most common metastatic sites from carcinoma breast include the bones, lungs, liver, and brain. Breast cancer metastasizing to the gastrointestinal tract is very rare. This case report is about a compliant woman who was a known treated case of right breast cancer, in whom ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography showed a focal FDG avid mural thickening in the body of stomach 4 years later, for which suspicion of a second primary of gastric origin was raised, considering the rarity of being metastatic. However, histopathology confirmed it as metastasis of breast origin. This case highlights the importance of considering gastric metastasis as a differential diagnosis in patients who present with a gastric lesion and a history of breast cancer.

Purpose: Hemophagocytic lymphohistiocytosis (HLH) is a fatal systemic inflammatory syndrome caused by a wide array of causes, which may be detected on ¹⁸F fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F FDG PET/CT). This study explores the utility of ¹⁸F FDG PET/CT in HLH.

Materials and methods: Retrospective data of HLH patients referred for whole-body ¹⁸F FDG PET/CT were analyzed for abnormal findings, and quantitative analysis using standardized uptake value (SUV), spleen-to-liver ratio (SLR), and bone-to-liver ratio (BLR) was done and correlated with laboratory parameters, bone marrow (BM) findings, and final diagnosis.

Results: Twenty-four patients (median age 22 years [interquartile range 13-34]) were included in the study. The most common cause of HLH was infection (33%), malignancy (29%), and autoimmune disorders (13%), and five patients had primary HLH. ¹⁸F FDG PET/CT was positive in 22/24 patients (92%). Hepatomegaly and splenomegaly were observed in 22 patients (92%) and 16 patients (67%), respectively, with six (25%) showing splenic lesions. Splenic uptake > liver was observed in 62.5% of patients and BM uptake > liver uptake in 50% of patients. There was no significant difference in median BM uptake (SUV_max 4.0 vs. 3.5, P = 0.6) and BLR (1.475 vs. 1.514, P = 0.4) in patients with and without HLH on marrow sampling, but a significant difference was observed in hypercellular vs. normocellular/hypocellular marrow (SUV_max 5.1 vs. 3.2, P = 0.019 and BLR 1.58 vs. 0.82, P = 0.043). A significant positive correlation was observed between splenic and BM uptake (r = 0.501, P = 0.013), BLR and SLR (r = 0.623, P = 0.001), C-reactive protein levels with BLR (r = 0.731, P = 0.001), and SLR (r = 0.594, P = 0.015), respectively. In 11 patients who underwent targeted sampling from most hypermetabolic sites, it helped reach the final diagnosis or eliminate malignant causes.

Conclusion: ¹⁸F FDG PET/CT has a high diagnostic yield in HLH with the potential to detect its underlying causes and may be considered in the diagnostic algorithm of HLH.

Purpose: The primary objective was to establish the reference value of gallbladder ejection fraction (GBEF) using a fatty meal-based hepatobiliary scintigraphy protocol tailored to the Indian population. In addition, the study assessed variations in GBEF across different time points and examined potential differences based on gender and age.

Materials and methods: This prospective study was conducted from January 2023 to January 2024. Hepatobiliary scintigraphy was performed on healthy individuals aged ≥18 years following a 4-h fasting period. Static images were acquired before and after ingesting a standard fatty meal. The premeal image displaying the highest gallbladder activity concentration and minimal liver activity was selected as the reference premeal image. GBEF was calculated using decay and background-corrected counts from the reference premeal and postmeal images. Statistical analyses included independent sample t-tests to evaluate gender differences, Pearson's correlation to assess relationships between age and GBEF, and repeated measures ANOVA with Bonferroni correction to compare GBEF across different time points. The reference value of GBEF was determined based on the 5^th percentile value at 60 min postmeal ingestion.

Results: Twenty-three consecutive healthy individuals (13 females and 10 males) with a mean age of 42 ± 12 years (median: 39 years; range: 23-62 years) participated in the study. The mean GBEF increased progressively over time, with values of 36% ± 20% at 30 min, 50% ± 23% at 45 min, and 55% ± 23% at 60 min, demonstrating statistically significant differences across time points (P < 0.0001). No significant differences in GBEF were observed between males and females at any time point (P ≥ 0.770). In addition, age was not significantly correlated with GBEF at any measured time point (P ≥ 0.820). The reference value of GBEF, determined based on the 5^th percentile at 60 min postmeal ingestion, was established as ≥20%, providing a clinically relevant threshold for assessing gallbladder function.

Conclusion: The study established the reference value of GBEF using a standard fatty meal protocol. In addition, using a culturally appropriate, low-cost fatty meal offers a practical alternative to sincalide-based cholescintigraphy, especially where sincalide is scarce or quality control is challenging. This patient-friendly method also shortens imaging sessions, reducing discomfort. These values support diagnostic thresholds in clinical practice.

Purpose: ¹⁸F fluoro 2-deoxy-D-glucose (FDG) uptake in positron emission tomography/computed tomography (PET/CT) scans is commonly observed in the brain, myocardium, liver, intestines, and excretory pathways such as kidneys and the urinary bladder. This study examines the incidence and contributing factors for physiological FDG accumulation in the gallbladder (GB) lumen, in the absence of clinical history or anatomical abnormalities.

Materials and methods: This retrospective study was conducted at a North Indian tertiary care hospital on patients who underwent ¹⁸F FDG PET/CT between January and August 2024. The study group included individuals with GB intraluminal FDG uptake exceeding blood pool levels without anatomical changes, while the control group comprised patients without GB uptake. Comparisons were made based on body mass index, fasting blood sugar, FDG dose, time-to-scan interval, and SUVmax (standardized uptake value). Mann-Whitney U-test was employed for statistical analysis.

Results: Among 632 screened patients, 82 (13%) exhibited GB FDG uptake, whereas 149 were randomly selected for the control group. The study group showed significantly higher fasting blood sugar (101 [24] vs. 93 [18] mg/dl, P = 0.007), FDG dose (6.8 [2.5] vs. 6 [2.3] mCi, P < 0.001), and longer time to scan (82 [54] vs. 78 [38] min, P = 0.02). The median SUVmax for GB uptake was 2.1 (0.93) g/ml.

Conclusion: Physiological GB FDG uptake occurs in about 13% of patients. Increased fasting blood sugar, higher FDG dose, and prolonged scan intervals elevate the likelihood of GB uptake.

Purpose: India's high-volume healthcare system, including nuclear medicine departments, restricts the quality and frequency of patient-clinician communication. Poor understanding of preparation requirements increases cancellations, image artefacts, and repeat studies. Artificial intelligence (AI) chatbots like chat generative pre-trained transformer (ChatGPT) can be a promising tool to mitigate these challenges. We evaluated the efficiency of ChatGPT to address patients' queries about study instructions and report findings while undergoing nuclear myocardial viability study.

Subjects and methods: Six myocardial-viability mock reports were created. OpenAI ChatGPT-4o responses were evaluated for the set of 14-questions regarding patient preparation and 2-questions regarding the reports. All questions and reports were entered as single prompts in separate chats. Each prompt was repeated twice using regenerate-response function. Furthermore, references used to generate responses were analyzed. The responses were then rated based on 5 key parameters: appropriateness, helpfulness, empathy, consistency, and validity of references.

Results: Most responses were appropriate and helpful for both preparation (1.5 ± 0.76; 1.64 ± 0.63) and report prompts (1.67 ± 0.49; 2.0). However, empathy and consistency had lower scores in preparations (1.43 ± 0.76; 1.14 ± 0.66) than in report prompts (1.58 ± 0.51; 1.67 ± 0.49). Reference validity remained an issue, as only one response had a valid reference. A hallucinatory response was noted twice. The study demonstrated that none of the prompt responses could have caused harm to the patient under real-life conditions.

Conclusions: ChatGPT helps in query resolution in myocardial viability studies. It enhances patient engagement, quality of patient preparation, and comprehension of nuclear medicine reports. However, inconsistent and less empathetic responses mandate supervised use and further refinement before incorporating it into routine practices.

IgG4-related disease (IgG4-RD) is a systemic autoimmune fibroinflammatory condition in which IgG4-positive plasma cell infiltration occurs in various organs. Diagnosing IgG4-RD when it presents as a lung mass can be challenging, as its clinical and radiological characteristics resemble those of lung cancer, and its presentation is also not diagnostic. This case presents an elderly male, a former smoker, with a lung mass, initially suspected to be lung carcinoma due to heterogeneous enhancement and spiculated margins on Contrast enhanced computed tomography (CECT). The diagnosis remained uncertain post-computed tomography (CT)-guided biopsy. FFlurodeoxyglucose Positron Emission Tomography- Computed Tomography (FDG PET-CT) revealed a metabolically active lung mass with mediastinal lymphadenopathy. Metabolic PET-CT-guided biopsy confirmed IgG4-RD with IgG4-positive plasma cells. This prevented unnecessary invasive procedures and ensured timely and appropriate treatment. The patient showed symptomatic improvement with steroid therapy. This unique case emphasizes the importance of combining metabolic imaging with metabolic intervention to accurately detect rare, isolated pulmonary IgG4-RD, which can clinically and radiologically mimic lung carcinoma.

Rosai-Dorfman disease (RDD) also called as sinus histiocytosis with lymphadenopathy is a rare benign histiocytic proliferative disorder of unknown etiology and was first described in 1969 with the incidence of 1 in 200,000. Most commonly present with lymphadenopathy with around 40 percent presented with extranodal involvement such as skin, central nervous system, nasal cavity, and bones. Bone involvement is rare and it is <10% cases of RDD. We present a case of RDD with extranodal involvement such as nasal cavity, cutaneous nodules, paraspinal lesion with intraspinal extension, and uncommon appendicular skeleton involvement (tibia and fibular involvement).

A 69-year-old gentleman presented with complains of giddiness, gait ataxia, vomiting, and slurring of speech with clinical signs pointing to cerebellar etiology. The magnetic resonance imaging brain revealed no significant abnormality. ¹⁸F-fluorodeoxyglucose (¹⁸F FDG) positron emission tomography (PET)/computed tomography showed hyper-metabolism in bilateral cerebellar hemispheres, pons, mid-brain and bilateral medial temporal cortices. Further quantitative NeuroQ analysis of ¹⁸F FDG-PET showed similar findings. Paraneoplastic antibody panel (anti-Hu, anti-Yo, anti-Ri, NMDA, CASPR-2 etc.) was negative. Clinical suspicion and PET imaging correlation led the neurologist to suspicion of inflammatory/autoimmune etiology, and the patient was empirically started on four cycles of plasma exchange therapy and course of steroids, however, no significant clinical response was noted. At post-6 months of ¹⁸F FDG-PET, he expired out of respiratory illness (pneumonia).

Equilibrium radionuclide angiocardiography (ERNA) is a highly accurate and well-established nuclear imaging modality for ventricular function evaluation. This technique exploits the binding of technetium-99m, in its reduced form, to intracellular constituents of erythrocytes - referred to as red blood cell (RBC) radiolabeling. Sufficient radiolabeling depends on an adequate number of circulating RBCs to generate optimal signal-to-background ratio and image contrast. Theoretically, a reduction in RBC count may compromise radiolabeling efficiency, culminating in suboptimal image quality. This report elucidates the deleterious effects of hypocellular anemia on ERNA imaging and documents the remarkable improvement in diagnostic image quality following targeted intervention to correct anemia.

Purpose: The primary objective was to establish the normative data of dynamic salivary gland scintigraphy (dSGS). Secondary objectives included comparing salivary gland function across different glands, examining gender differences, and correlations with age.

Materials and methods: Twenty-nine consecutive healthy adults (19 females) with a mean age of 46.5 ± 11.9 years underwent dSGS. Scintigraphy images were analyzed visually and quantitatively, generating dynamic salivary scintigrams for each gland. Quantitative indices such as maximum percent uptake (MU%) and excretion fraction (EF%) were calculated. Comparisons between the parotid and submandibular glands, as well as between genders, were performed using the Mann-Whitney U-test or Independent Samples t-test. Spearman's rank correlation was used to analyze the relationship between age and the quantitative indices. Reference values for MU% and EF% were determined using the 5^th percentile and the mean - 1.645 × standard deviation, respectively.

Results: On visual analysis, parotid glands showed higher radiotracer uptake than submandibular glands. The dynamic scintigram displayed three distinct phases: accumulation, excretion, and re-accumulation. EF% was significantly higher in parotid than submandibular glands (P < 0.0001). No significant gender differences were found in MU% (P ≥ 0.422), but females had higher EF% in the parotid glands (P = 0.004) and a trend toward higher EF% in submandibular glands (P = 0.058). A weak positive correlation was noted between age and the MU% of the submandibular glands (Spearman's ρ = 0.391, P = 0.036). The reference cutoffs for MU% and EF% were determined to be ≥0.23% and ≥50% for parotid glands and ≥0.18% and ≥32% for submandibular glands, respectively.

Conclusion: This study established normative data of dSGS for evaluating salivary gland function. Further research with larger cohorts is recommended to explore age and gender variations and to validate these findings across diverse populations.