BackgroundBlood loss from the gastrointestinal tract can be an acute and life-threatening event. For the treatment of gastrointestinal bleeding, it is important to accurately detect gastrointestinal bleeding and to localize the sites of bleeding. The purpose of this study was to retrospectively assess the capabilities of SPECT/CT in the diagnosis of gastrointestinal bleeding by a comparison with planar imaging alone as well as planar and SPECT.MethodsWe conducted a retrospective analysis of 20 patients (21 examinations) who underwent gastrointestinal bleeding scintigraphy in the past 7 years and in whom the bleeding site was identified by endoscopy or capsule endoscopy, or in whom no evidence of gastrointestinal bleeding was identified during the clinical course. Five patients (5 examinations) were diagnosed by planar imaging (planar group). Eight patients (9 examinations) were diagnosed by planar imaging and SPECT (planar + SPECT group). Seven patients (7 examinations) were diagnosed by planar imaging and SPECT/CT (planar + SPECT/CT group). We calculated the diagnostic ability of each method in detecting the presence of bleeding, as well as the ability of each method to identify the sites of bleeding. The sensitivity, specificity, and accuracy of the methods were compared.ResultsThe diagnostic ability of the three imaging methods in detecting the presence of gastrointestinal bleeding was as follows. Planar imaging showed 100% sensitivity (3/3), 100% specificity (2/2), and 100% accuracy (5/5). Planar + SPECT imaging showed 85.7% sensitivity (6/7), 100% specificity (2/2), and 88.9% accuracy (8/9). Planar + SPECT/CT imaging showed 100% sensitivity (6/6), 100% specificity (1/1), and 100% accuracy (7/7). The diagnostic ability of the three modalities in detecting the site of bleeding was as follows: planar, 33.3% (1/3); planar + SPECT, 71.4% (5/7); and planar + SPECT/CT, 100% (6/6).ConclusionsAll 3 imaging methods showed good accuracy in detecting the presence of gastrointestinal bleeding. The addition of SPECT or SPECT/CT made the anatomical position of the uptake clear and contributed to the localization of the site of gastrointestinal bleeding. Planar + SPECT/CT imaging therefore showed the highest diagnostic ability for detecting the site of gastrointestinal bleeding.

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Background: Various imaging modalities are used to identify and characterize cardiac masses. While echocardiography remains the preferred imaging modality to evaluate cardiac masses, computed tomography (CT), magnetic resonance imaging (MRI), and 18 F-fluorodeoxyglucose positron emission tomography (18 F-FDG PET)/CT are being increasingly employed to assess cardiac mass lesions. However, the clinical value of noninvasive cardiac imaging for differentiating between primary cardiac mass and metastatic lesions has not yet been examined in detail. The purpose of the present study was to evaluate the diagnostic utility of non-invasive cardiac imaging for differentiating primary cardiac tumors from metastatic lesions, and non-tumorous lesions. Methods: A retrospective review was conducted on 22 cardiac mass lesions in 20 patients assessed by cardiac imaging (at least one of CT, MRI, or 18 F-FDG PET/CT) between December 2005 and March 2017. CT findings included the tumor size, location, existence of calcification, and morphology of the base portion of the lesion. MRI parameters included signals with T1-weighted imaging (T1WI), T2WI, mobility with cine imaging, and contrast enhancement. Tracer uptake by each cardiac lesion using 18 F-FDG PET/CT was also evaluated. Results: Among 17 cardiac mass lesions assessed by contrast-enhanced CT, all cardiac myxomas and papillary fibroelastomas had a pedunculated base portion. All metastases located in the cavity had a sessile base portion (P=0.0035). Malignant tumors (metastases and malignant lymphoma) had no mobility, while cardiac myxomas had a slightly higher frequency of mobility with cine MRI (0% vs. 100%, P=0.0667). Among the four lesions for which 18 F-FDG PET/CT was performed, the three malignant lesions had strong 18 F-FDG uptake, while the benign lesion showed insignificant accumulation. Conclusions: The characteristics of the base portion of cardiac mass were useful for differentiating primary cardiac tumors from metastatic cardiac tumors. Cine MRI also exhibited diagnostic utility for differentiating between primary cardiac tumors and metastases. Therefore, non-invasive cardiac imaging may be employed to differentiate cardiac mass lesions. The accurate diagnosis of cardiac mass lesions may require the assessment of multiple characteristics on images.