Hassan Siddiki MD, Presenter: Nothing to Disclose

Joel Garland Fletcher MD, Abstract Co-Author: Research grant, Siemens AG Grant, E-Z-EM, Inc License agreement, General Electric Company

David Bruining MD, Abstract Co-Author: Nothing to Disclose

Amy Kiyo Hara MD, Abstract Co-Author: License agreement, General Electric Company

James M. Kofler PhD, Abstract Co-Author: Nothing to Disclose

Darrell S. Pardi MD, Abstract Co-Author: Nothing to Disclose

James E. Huprich MD, Abstract Co-Author: Nothing to Disclose

Jeff Lynn Fidler MD, Abstract Co-Author: Grant, E-Z-EM, Inc, Lake Success, NY

Edward Loftus, Abstract Co-Author: Nothing to Disclose

Cynthia H. McCollough PhD, Abstract Co-Author: Research grant, Siemens AG Research grant, RTI Electronics AB

et al, Abstract Co-Author: Nothing to Disclose

et al, Abstract Co-Author: Nothing to Disclose

Patients with Crohn’s Disease (CD) can receive large total effective radiation doses, largely arising from the use of CT. We sought to determine the performance of a lower dose CT enterography (CTE) technique for active inflammatory Crohn’s disease.

CTE protocols in our practice had estimated effective doses ranging from 16 - 20 mSv. 72 consecutive CD patients underwent CTE between 1/06 – 4/06 using a lower dose technique (12 mSv) using 16 channel MDCT (155 mAs, 120 kV, pitch 0.94, detector configuration 16 x 0.75), a 33-66% dose reduction. Ileoscopy was performed within 30 days. Using ileoscopy and histology reports, a gastroenterologist created a reference standard, rating CD as definitely active, probably active and inactive. Two GI radiologists evaluated CTE datasets, rating ileal disease as being definitely active, probably active or inactive, based upon mural hyperenhancement, stratification, wall thickness and other findings. All fistulas and abscesses were recorded.

Sensitivity for definite active inflammatory CD in the ileum visualized at ileoscopy was 94% (31/33) and 82% (27/33), for readers 1 and 2, respectively, and 87% (46/53) and 77% (41/53) for definitely and probably active disease. The specificity for the absence of CD for readers 1 and 2 was 53% (10/19) and 58% (11/19). 8/9 false positive exams were identical for both readers (2=fistulizing disease, 7=marked hyperenhancement). 44% (32/72) of patients had small bowel disease beyond reach of the endoscope, and 28% (20/72) had fistulas and/or abscesses.

1) Lower-dose CTE performs similarly to standard CTE in detecting active inflammatory Crohn’s disease. 2) Lower-dose CTE should be performed in patients with known Crohn’s disease to reduce the cumulative effective dose, given the relapsing and remitting nature of the disease. 3) Use of radiation for CTE is justified in Crohn’s patients given the high frequency of active and penetrating disease.

Lower-dose CTE can be performed on patients with known Crohn’s disease without sacrificing sensitivity, with radiation burden justified given the prevalence of penetrating and active disease.

Siddiki, H, Fletcher, J, Bruining, D, Hara, A, Kofler, J, Pardi, D, Huprich, J, Fidler, J, Loftus, E, McCollough, C, et al, , et al, , Performance of Lower-Dose CT Enterography for Detection of Inflammatory Crohn’s Disease (CD).  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5011902.html