The role of mdct in the evaluation of colorectal disorders

Multidetector CT (MDCT) instruments made possible to develop new diagnostic tools, such as virtual colonoscopy for the evaluation of colorectal disorders.

Purpose: To evaluate the diagnostic value of virtual colonoscopy in different colorectal disorders and to establish whether the introduction of this new radiologic method had a significant impact on the diagnostic workup of these diseases.

Patients, methods: Seven hundred and forty-five double contrast colonografies and 396 virtual colonoscopies were performed between 2005 and 2007. The virtual colonoscopies were performed by GE Lightspeed 16 slice CT intrument. For the evaluation 2D (MPR), 3D and virtual reconstruction were applied.

Results: We have performed 314 double contrast colonografies in 2005, 245 in 2006 and 186 in 2007, while 61, 143 and 192 virtual colonoscopies were performed respectively. During the same period 515, 1763 and 1812 colonoscopies were carried out. For polyps larger than 5mm virtual colonoscopy had 88.4% sensitivity, 98% specificity, 0.88 positive predictive value and 0.98 negative predictive value. In the diagnosis of diverticula these results were 95.1%, 99.1%, 0.73 and 0.93 respectively. Tumors and narrowings were diagnosed in 100% with virtual colonoscopies and colonoscopies

Conclusion: The emerging role of MDCT in the evaluation of colorectal disorders, may be explained by the better visualisation of the abnormalities of the colonic wall. Furthermore, it provides information on the mesenterium and on the lymphnodes as well. Due to the high sensitivity and specificity values it became a real alternative of the classical double contrast colonography