Technological value of SPECT/CT fusion imaging for the diagnosis of lower gastrointestinal bleeding.

The aim of this study was to assess the clinical value of diagnosing and locating lower gastrointestinal (GI) bleeding using single photon emission computed tomography (SPECT)/computed tomography (CT) fusion imaging with 99mTc labeled red blood cells ((99m)Tc-RBC). Fifty-six patients with suspected lower GI bleeding received a preoperative intravenous injection of (99m)Tc-RBC and each underwent planar, SPECT/CT imaging of the lower abdominal region. The location and path of lower GI bleeding were diagnosed by contrastive analysis of planar and SPECT/CT fusion imaging. Among the 56 patients selected, there were abnormalities in concentrated radionuclide activity with planar imaging in 50 patients and in SPECT/CT fusion imaging in 52 patients. Moreover, bleeding points that were coincident with the surgical results were evident with planar imaging in 31 patients and with SPECT/CT fusion imaging in 48 patients. The diagnostic sensitivity of planar imaging and SPECT/CT fusion imaging were 89.3% (50/56) and 92.9% (52/56), respectively, and the difference was not statistically significant (χ(2) = 0.11, P > 0.05). The corresponding positional accuracy values were 73.8% (31/42) and 92.3% (48/52), and the difference was statistically significant (χ(2) = 4.63, P < 0.05). (99m)Tc- RBC SPECT/CT fusion imaging is an effective, simple, and accurate method that can be used for diagnosing and locating lower GI bleeding.