Mehmet Selim Nural, Presenter: Nothing to Disclose

Murat Danaci, Abstract Co-Author: Nothing to Disclose

Ahmet Soyucok, Abstract Co-Author: Nothing to Disclose

Nilgun Ozbek Okumus, Abstract Co-Author: Nothing to Disclose

To evaluate the efficiency of diffusion weighted magnetic resonance imaging (DW-MRI) in diagnosis of local recurrences of colorectal tumors during postoperative period.

Twenty-one patients who were operated for colorectal tumor and a mass was detected on their postoperative follow-up computed tomography (CT) and/or MRI were included into the study. The final diagnosis was done according to the findings of colonoscopy/biopsy, operation, clinical laboratory findings and/or follow-up radiological imaging (CT/MRI) findings. Approval for the study was obtained from Ethical Committee of our hospital. DWI was performed using a 1.5 T whole-body scanner equipped with a phased-array body coil. DW-MRI echo planar sequence was obtained on axial plane. The scan protocol was TR/TE:3300/93 msec, slice thickness 5 mm, field of view (FOV) 400 mm and b factor 0 and 800 s/mm2. The median apparent diffusion coefficient (ADC) values of the lesions were calculated by manual drawing of Region of Interest (ROI) on ADC maps.

A diagnosis of recurrence was done in 11 patients (group 1) and benign fibrosis/granulation tissue was diagnosed in 10 patients (group 2) according to final diagnosis. Median ADC values were 1,07x10-3 mm2/sec (min: 0,82- max 2,05) and 1,92 x10-3 mm2/sec (min: 1,51 – max: 2,20) in group 1 and group 2, respectively. There was a statistically significant difference in between two groups (p<0.001). When a threshold level of 1,48 x10-3 mm2/sec was used to determine whether the lesions were recurrence or not by ROC analysis, sensitivity was 90%, specificity was 100%, positive predictive value was 100% and negative predictive value was 90%. Area under the curve (AUC) was 0,93 and this value was statistically significant (p<0,001).

DW-MRI appears to be a considerably reliable imaging method in detection of local recurrences of colorectal tumors.

DW-MRI can be used reliably for differentiation of masses detected on postoperative follow-up of colorectal tumors as malign or benign.

Nural, M, Danaci, M, Soyucok, A, Okumus, N, Efficiency of Diffusion MRI in Detection of Colorectal Tumor Recurrences.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014292.html