Clinical Significance of Hepatobiliary Localization of Tc-99m EC in Diuretic Renography.

Objective Technetium-99m ethylene dicysteine (Tc-99m EC) is a well-established, tubular tracer for diuretic renography. Few occasional cases have been reported in literature regarding visualization of liver, gallbladder (GB), or bowel due to increased hepatobiliary route of excretion of Tc-99m EC on diuretic renography. This study aimed to retrospectively review the incidence of visualization of liver, GB, or bowel and its clinical significance in Tc-99m EC diuretic renography. Materials and Methods Data of all patients who underwent diuretic renography in the department from January 24, 2022 to March 31, 2023 was included in the study. The data was analyzed to assess the incidence of visualization of GB or bowel loops, correlation of the hepatobiliary localization with factors like age of the patient, concentration of 99m TcO4 solution, quality control parameters, presence of renal stone disease, serum creatinine, relative renal function, and effective renal plasma flow. Effect of hepatobiliary localization on scan interpretation and reporting was assessed. Results The retrospective analysis of 437 diuretic renograms revealed the hepatobiliary localization of tracer in 34 patients. Out of these 34 patients, 14 patients had only faint visualization of tracer at 4 hours delayed image. Twenty scans had visualization of both GB and bowel. Out of these 20 scans, GB and bowel were visualized during dynamic imaging in one scan, after initial 20 minutes in two scans and in 2 to 4 hours delayed images in rest of the 17 scans. Two out of 20 patients had increased serum creatinine, 16 patients had either single kidney or relative renal function less than 26%, and 12 patients had renal stone disease. Out of the four patients in whom relative renal function was more than 25%, one patient had raised serum creatinine and three patients had renal stone disease. Interpretation of images was affected only in three patients, in which reporting of the scans required single-photon emission computed tomography imaging and correlation with other imaging modalities. Conclusion Hepatobiliary excretion of Tc-99m EC usually does not usually affect the scan interpretation and quantitative renogram analysis, but reader should be cognizant of the potential pitfalls during scan interpretation. In this study, we reviewed the possible causes of this hepatobiliary clearance and importance of additional views and correlation with other imaging modalities to clarify the suspicion arises for accurate reporting.

Tc-99m MDP Scan with Unusual and Isolated Skeletal Metastasis in Skull Bone in a Case of Testicular Seminoma.

Seminomas are common germ cell tumors (GCT) that may arise in the testes as well as in extra testicular locations such as mediastinum with/without testicular tumor. Testicular tumors are usually detected early due to their location and presentation as testicular mass. The overall prognosis of the seminomatous GCTs is good with surgery as the mainstay of treatment in localized disease. Bone metastases, especially when present in isolation are exceedingly rare in seminoma. Here, we present a rare case of skull bone metastasis in a case of testicular seminoma which was detected on technetium-99m labeled methylene diphosphonate bone scintigraphy with single-photon emission computed tomography with computed tomography.

The 'Eye Mask Sign' in Fibrous Dysplasia on 99mTc-MDP Skeletal Scintigraphy and SPECT/CT.

Fibrous dysplasia (FD) is a fibro-osseous disorder that manifests with distinct or overlapping clinical patterns. FD may be monostotic or polyostotic and commonly associated with syndromes such as McCune-Albright syndrome and Mazabraud syndrome. We report a case of polyostotic FD with bilateral involvement of craniofacial bones in a distinct pattern and propose this characteristic appearance as the 'eye mask sign' on 99mTc-Methylene Diphosphonate (MDP) skeletal scintigraphy and SPECT/CT. Other unusual skeletal scintigraphic features noted in this case are also described (Figs. 1, 2, and 3).

Scope of PET imaging in the evaluation of cardiac tumors.

Cardiac and pericardial masses can be categorized as neoplastic (either benign or malignant), non-neoplastic (such as thrombus or pericardial cysts), or normal variants of the cardiac structure. Diagnosing these masses can be challenging, and various imaging modalities are available, with each of them having advantages and pitfalls. Echocardiography is typically the first test used for the evaluation and detection of cardiac masses, as it is widely accessible, portable, and provides a comprehensive assessment of cardiac function and valves without the use of ionizing radiation. However, it may not be helpful in some cases, such as evaluating the extracardiac extension of the mass or characterizing tissue. On the other hand, cross-sectional imaging can provide a three-dimensional data set with excellent spatial resolution. Still, it requires ionizing radiation and intravenous iodinated contrast, and its functional evaluation of the heart may be relatively limited. 18F-FDG PET/CT helps determine 18F-FDG PET/CT is a crucial molecular imaging modality to assess and differentiate benign and malignant cardiac tumors noninvasively and helps in treatment planning and prognostication. Currently, studies evaluating the role of 18F-FDG PET/CT in cardiac tumors are limited to case reports and single center studies.

An overview of radiolabeled amino acid tracers in oncologic imaging.

Molecular imaging has witnessed a great progress in the field of oncology over the past few decades. Radiolabeled amino acid (AA) tracers are particularly helpful in the areas where the utility of 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography with computed tomography imaging has been limited such as in evaluating brain tumors, neuroendocrine tumors (NETs), and prostate cancer. Radiolabeled AA tracers such as 6-[18F]-L-fluoro-L-3, 4-dihydroxyphenylalanine (18F-FDOPA), 18F-fluoro-ethyl-tyrosine (18F-FET), and 11C-methionine have found wide applications in brain tumors, which, unlike 18F-FDG, concentrate in the tumor tissue to a greater extent than that in normal brain tissue by providing accurate information about tumor volume and boundaries. 18F-FDOPA is also useful in evaluating NETs. Tracers such as 18F-FACBC (Fluciclovine) and anti-1-amino-2-[18F]fluorocyclopentyl-1-carboxylic acid (18F-FACPC) are used in imaging of prostate cancer and provide valuable information of locoregional, recurrent, and metastatic disease. This review highlights AA tracers and their major applications in imaging, viz., in evaluating brain tumors, NETs, and prostate cancer.

Thyroid scintigraphy and hybrid SPECT/CT in a rare case of dual ectopic thyroid.

Dual ectopic thyroid (DET) is a rare disorder occurring as a result of aberrant embryonic development characterized by simultaneous presence of thyroid tissue at two ectopic sites. 99mTc-Pertechnetate thyroid scintigraphy remains gold standard in confirming ectopic thyroid tissue. This case highlights the importance of thyroid scintigraphy and Single Photon Emission Computed Tomography with Computed Tomography (SPECT/CT) in evaluation of ectopic thyroid tissue and DET that manifested itself during patients' pregnancy.

Comparison of gastric motility in patients of type 2 diabetes mellitus with various degrees of glycemic control.

The aim of this study was to evaluate the effect of glycemic control as estimated by glycated hemoglobin A1c (HbA1c) on gastric emptying in patients with type 2 diabetes mellitus (DM) using gastric emptying scintigraphy (GES). This was a cross-sectional study conducted at a tertiary health care center in Northern India. The study included 44 patients who underwent GES using a radiolabeled solid Idli meal containing 1 mCi of Tc-99 m Sulfur Colloid. Patients were divided into three groups based on glycemic control as Group A, B, and C with HbA1c <7%, 7%-9%, and >9%. Statistical analysis was performed using the IBM® SPSS® Statistics Version 23.0 The comparison of proportions was done using the Chi-square test and Fisher's exact test. Means were compared using the independent t-test and one-way analysis of variance. P < 0.05 was considered statistically significant. No statistically significant correlation was found between delayed gastric emptying and glycemic control (P = 0.09), gender (P = 0.228), dietary patterns (P = 0.91), symptoms of gastroparesis (P = 0.06), body mass index (BMI) (P = 0.267), and duration of type 2 DM (P = 0.565). No statistically significant association was also found between glycemic control and time taken for half gastric emptying (t1/2) (P = 0.225). Scintigraphy using Tc-99m Sulfur Colloid radiolabeled Idli meal can be effectively used for the assessment of gastric emptying. There is no significant correlation of delayed gastric emptying with glycemic control, gender, BMI, type of diet, and duration of diabetes mellitus.