gadoxetic-acid-disodium and Gastrointestinal-Stromal-Tumors

To evaluate the correlation of risk grade of gastrointestinal stromal tumours (GISTs) based on modified National Institutes of Health (NIH) criteria with conventional magnetic resonance (MR) imaging and diffusion-weighted (DW) imaging.. We included 22 patients with histopathologically proven GISTs in the stomach or small bowel who underwent pre-operative gadoxetic acid-enhanced MR imaging and DW imaging. We retrospectively assessed correlations between morphologic findings, qualitative (signal intensity, consensus from two observers) and quantitative (degree of dynamic enhancement using signal intensity of tumour/muscle ratio and apparent diffusion coefficient [ADC]) values, and the modified NIH criteria for risk stratification. Spearman partial correlation analysis was used to control for tumour size as a confounding factor. The optimal cut-off level of ADC values for intermediate or high risk GISTs was analyzed using a receiver operating characteristic analysis.. Except tumour size and necrosis, conventional MR imaging findings, including the degree of dynamic enhancement, were not significantly different according to the modified NIH criteria (p>0.05). Tumour ADC values were negatively correlated with the modified NIH criteria, before and after adjustment of tumour size (ρ=-0.754; p<0.001 and ρ=-0.513; p=0.017, respectively). The optimal cut-off value for the determination of intermediate or high-risk GISTs was 1.279 × 10(-3)mm(2)/s (100% sensitivity, 69.2% specificity, 81.8% accuracy).. Except tumour size and necrosis, conventional MR imaging findings did not correlate with the risk grade. However, the ADC value can be used as an imaging biomarker to assess the risk grade of GISTs, regardless of tumour size.

Topics: Adult; Aged; Diffusion Magnetic Resonance Imaging; Female; Gadolinium DTPA; Gastrointestinal Neoplasms; Gastrointestinal Stromal Tumors; Humans; Male; Middle Aged; Neoplasm Grading; Radionuclide Imaging; Reproducibility of Results; Retrospective Studies; Risk; ROC Curve; Sensitivity and Specificity

A primary gastrointestinal stromal tumor (GIST) arising in the liver is extremely rare. In our case of GIST, CT and MRI showed a well-defined, weakly enhancing mass with a cystic component in the left lateral segment of the liver that showed homogeneous and avid (18)F-fluorodeoxyglucose ((18)F-FDG) accumulation on positron emission tomography/computed tomography (PET/CT). We herein present a rare case of primary malignant GIST of the liver presenting with peritoneal seeding on CT, gadoxetic acid-enhanced MRI and (18)F-FDG PET/CT.

Topics: Aged; Contrast Media; Diagnosis, Differential; Diagnostic Imaging; Fluorodeoxyglucose F18; Gadolinium DTPA; Gastrointestinal Stromal Tumors; Humans; Image Enhancement; Iohexol; Liver; Liver Neoplasms; Magnetic Resonance Imaging; Male; Multimodal Imaging; Positron-Emission Tomography; Radiopharmaceuticals; Tomography, X-Ray Computed