Imaging of Gastrointestinal Bleeding: An Update.

Imaging of gastrointestinal bleeding crucial in the diagnosis of occult gastrointestinal bleeding. Gastrointestinal bleeding scintigraphy is a well-established study to aid localisation of gastrointestinal bleeding site. This article discusses about the use of gastrointestinal bleeding scintigraphy in its current practice with emphasis on radiopharmaceutical, imaging techniques, interpretation and pitfalls. There is also discussion on the use of Single Photon Emission Computed Tomography-Computed Tomography (SPECT-CT) within this method of scintigraphy. Meckel's diverticulum is known to be a frequent source of bleeding, mainly in children. It is also know that nuclear medicine imaging can help with Meckel's diverticulum identification. This article also discusses about the technique, imaging, interpretation and SPECT-CT usage for Meckel's diverticulum imaging.

The incidence and duration of COVID-19 vaccine-related reactive lymphadenopathy on 18F-FDG PET-CT.

OBJECTIVES: Reactive axillary lymph nodes (ALN) may occur post-COVID-19 vaccination. This may be confused with malignant nodal metastases on oncological imaging. We aimed to determine the reactive ALN incidence and duration on 18F-fluorodeoxyglucose positron emission tomography - computed tomography (18F-FDG PET-CT), and its relationship with gender, age and vaccine type. METHODS: A retrospective study was performed. Two-hundred and four eligible patients had 18F-FDG PET-CT between 01 January 2021 and 31 March 2021, post-vaccination with Pfizer-BioNTech or Oxford-AstraZeneca vaccine. Image analysis was performed on dedicated workstations. SPSS was used for statistical analysis. RESULTS: Thirty-six per cent of patients had reactive ALN until 10 weeks post-vaccination; reducing in frequency and intensity with time. Women were more likely to have reactive ALN compared with men. The frequency and intensity were higher in patients aged <65 years compared with those aged ≥65 years. However, no difference was found between both vaccine types in our study cohort. CONCLUSIONS: Physicians' awareness of COVID-19 vaccine-related reactive ALN on 18F-FDG PET-CT is important to avoid inappropriate upstaging of cancers.

The prognosis and management of neuroendocrine neoplasms-related metastatic bone disease: lessons from clinical practice.

PURPOSE: To study the evolution and optimal management of metastatic bone disease (mBD) in patients with neuroendocrine neoplasms (NENs). METHODS: Seventy-four patients were recruited from four NEN centers in this observational multicenter study. RESULTS: Pancreas and small bowel were the most common primaries (30 and 27%, respectively). Almost all gastrointestinal (GI)-NENs were grades 1 and 2, whereas bronchopulmonary-thymic were atypical carcinoids. Thirty-two (43%) patients had synchronous metastatic bone disease (mBD) and three patients reported bone-specific symptoms; metachronous mBD developed at a median of 35 (range: 4-395) months. Thirty-six (86%) of patients with metachronous mBD had stage IV disease at diagnosis. Somatostatin receptor functional imaging and computed tomography were the modalities mostly used for mBD identification. Fifty-two patients received assessable bone-related therapy (bisphosphonates, denosumab, local radiotherapy, and radionuclide treatment). Improvement in mBD was seen in 5, stable disease in 22, and deterioration in 25 patients. The presence of synchronous mBD and the negative outcome of bone-related therapy negatively affected overall survival (OS). In the multivariate analysis, the stronger predictor of OS was the outcome of bone-related therapy (HR: 4.753; 95% CI: 1.589-14.213). Bisphosphonates therapy was the mostly used bone-specific treatment but its monthly administration did not affect OS. At last follow-up, 39 patients were alive with OS 50 (14-463) months. CONCLUSIONS: Early investigation for mBD offers a prognostic marker of patients with NENs, since synchronous mBD has a negative impact on survival. The outcome of bone-related therapy affects OS but the monthly administration of bisphosphonates did not show a benefit over less intense schemes.

Pitfalls and Limitations of Radionuclide Hepatobiliary and Gastrointestinal System Imaging.

Radionuclide imaging for the hepatobiliary and gastrointestinal system covers a wide range of different indications and imaging techniques. This wide variety allows the different functional assessments of both systems. Therefore, the understanding of each technique and its indications is essential. Cholescintigraphy is a well-established method in the assessment of acute and chronic cholecystitis. It also has a role in the detection of biliary atresia. The assessment of gastrointestinal transit is also well-established in radionuclide imaging for functional investigation of the gastrointestinal tract. Furthermore, detection of acute gastrointestinal bleeding with radionuclide imaging is also standard practice. This article aims to review the pitfalls and limitations in all of these areas.

Measuring SeHCAT retention: a technical note.

TauroH-23-((75)Se)selena-25-homocholic acid (SeHCAT) retention has been used for the diagnosis of bile acid malabsorption since the early 1980s. Bile acid malabsorption has been increasingly recognized as an important cause of severe chronic diarroea with subsequent increase in the number of referrals for the SeHCAT test. In this study, we review and discuss the standard techniques for the measurement of SeHCAT retention and describe a simple and modified technique using a noncollimated whole-body scanner, suitable for most modern dual-headed cameras.