Dilek Oncel MD, Presenter: Nothing to Disclose

Guray Oncel, Abstract Co-Author: Nothing to Disclose

Inanc Karapolat MD, Abstract Co-Author: Nothing to Disclose

Werner A. Bautz MD, Abstract Co-Author: Nothing to Disclose

Sedat Alibek MD, Abstract Co-Author: Nothing to Disclose

To evaluate the diagnostic value of whole body diffusion weighted MR imaging (WB-DWI) and T2 weighted MR imaging in comparison to positron emission tomography-CT (PET-CT) in metastasis evaluation

16 consecutive patients with suspected metastases from malignant tumors (NHL (n=4), gastric carcinoma (n=2), bronchial carcinoma (n=6), colon carcinoma (n=2), breast carcinoma (n=2) were examined with WB-MRI on an automatic moving table with a 1.5 T scanner (Avanto, Siemens Medical Solutions) using a five step scan in the coronal plane. T2 STIR, T1 FSE and SE-EPI sequences (b=0, 400, 800) with parallel acquisition technique were performed without i.v. Gd-administration. PET-CT images were obtained 45 minutes after 18F-FDG injection. PET-CT images were used as standard of reference. WB-MRI and the PET-CT findings were evaluated and compared as to the detection of metastases. Lesions were confirmed by follow-up over 6 months or biopsy.

1. PET-CT scan showed no evidence of metastasis in 6 patients and 15 metastasis in 10 patients (bone (n=5), liver (n=3), lymph nodes (n=5), lung (n=1), adrenal gland (n=1) 2. T2 weighted fat supressed images showed 21 high signal lesions including all metastasis but also 6 false positive lesions. High sensitivity (93%) but low specificity (71%) was found 3. WB-DWI showed high-signal intensities at high b-values (b=800) in all lesions except one lymph node metastasis in the mediastinum, which was obscured due to motion artifacts. High sensitivity (93%) and specificity (100%) rates were found for metastasis detection with WB-DWI. No false positive lesion was seen on WB-DWI.

1. T2 weighted fat supressed images showed higher sensitivity but lower specificity rates for metastasis detection than WB-DWI. 2. WB-DWI showed high sensitivity and specificity rates for metastasis detection compared with PET-CT imaging in our series. Limitations of WB-DWI for metastasis detection are motion artifacts, e.g. in the mediastinum.

WB-DWI is an effective method for whole body metastasis evaluation with MRI without radiation and Gd-administration with high sensitivity and specificity rates.

Oncel, D, Oncel, G, Karapolat, I, Bautz, W, Alibek, S, Value of Whole Body Diffusion-weighted MR Imaging (WB-DWI) in Comparison to T2-weighted MR Imaging and Positron Emission Tomography-CT (PET-CT) in Metastasis Evaluation.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5013421.html