Added value of SPECT/CT over planar Tc-99m mebrofenin hepatobiliary scintigraphy in the evaluation of bile leaks

Abstract

To determine the added value of single-photon emission computed tomography/computed tomography (SPECT/CT) over planar hepatobiliary scintigraphy (HBS) in suspected cases of bile leak. An analysis of the data of all patients who had undergone HBS for suspected bile leak during the last 3 years was carried out. All patients had undergone an initial 45 min dynamic study after an intravenous injection of Tc-99m mebrofenin, following which they underwent multiple static imaging studies for up to 24 h and SPECT/CT imaging whenever needed. A total of 203 patients had undergone an HBS for evaluation of a suspected bile leak. HBS was positive for bile leak in 110 patients, among whom 42 had undergone additional SPECT/CT. In 32 patients SPECT/CT was useful in (i) defining the exact location of collection [intracapsular vs. extracapsular vs. intraparenchymal leak (n=18/25)], (ii) defining the extent of intraparenchymal collections (n=6/6), (iii) characterizing large abdominal collections (n=2/2), and (iv) characterizing suspected contamination (n=4/4), (v) suspected collection (n=0/3), (vi) and other miscellaneous conditions (n=2/2). Defining the extent and exact localization of collection can have therapeutic implications such as the accurate site of placement of the drain for drainage. In approximately one-third of the bile leak-positive HBS studies (32/110), SPECT/CT images were helpful for better characterization of biliary collection. In all, 76% (32/42) of the SPECT/CT studies were found to provide additional useful information over planar imaging. Hybrid SPECT/CT offers the unique advantage of combining the anatomical information from CT with the functional information provided by HBS. It is most useful in characterization of biliary collections, which give important scintigraphic evidence of the severity of bile leak with therapeutic implications such as placement of a drain or surgical exploration.