Diagnostic imaging of carcinoid metastases to the abdomen and pelvis.

Background: Functional and anatomical imaging methods are currently the standard approach to the evaluation of carcinoid tumor extent. Due to the nature of carcinoid tumors ,there is not a single imaging procedure that is sufficient to detect the malignancy. The aim of the study was to compare the value of CT, MR and functional imaging study with(111) In-Octreotide (SRS) in carcinoid detection and evaluation of its extent as well as to work out the imaging studies diagnostic algorithm that could enhance diagnostic efficacy.
Material/methods: A total of 34 patients with carcinoid tumor confirmed clinically,biochemically and/or histopathologically were enrolled into the study. Computed tomography (CT) examinations of the abdomen and pelvis were performed before and after administration of a contrast medium, the triple-phase liver scanning included. Magnetic Resonance Imaging (MRI)of the liver was performed according to the standardized protocol before and after administration of a contrast medium .Planar scintigraphy with(111) In Octreotide and SPECT were performed. In each case liver as well as lymph node metastases in the abdomen and pelvis were searched for. All results were reviewed independently. Clinical picture at follow-up and further imaging and/or histological studies confirmed or excluded the diagnosis of the disease.
Results: Twenty nine patients were diagnosed with carcinoid tumor. Liver metastases were found in 26 patients and lymph node metastases were detected in 18 of them. Complete diagnostic conformity as far as the diagnosis and extent of the disease are concerned was obtained only in 7 cases. Incorrect assessment of the disease extent was the source of discrepancy between the imaging studies results in most of the remaining 22 patients. The SRS and MR results of liver metastases detection were mostly consistent with one another. Both imaging modalities evaluated the extent of hepatic metastases incorrectly in 22%of the patients,as compared to 43% of the patients for CT. The highest proportion percentages of incorrect results of lymphatic involvement detection were 41%, 29%and 43%for MR, SRS and CT, respectively.
Conclusions: The results of our study have indicated that application of a complex imaging algorithm enables higher accuracy of hepatic and lymph nodes metastases detection in carcinoid tumor patients. Combining the results of MR and SRS in evaluating the extent of the carcinoid disease seems to represent higher diagnostic value than relying on one of this method in combination with CT images.