Elie Portnoy MD, Presenter: Nothing to Disclose

Maria Christina Shiau MD, Abstract Co-Author: Nothing to Disclose

James S. Babb PhD, Abstract Co-Author: Nothing to Disclose

Rose Weiner BS, Abstract Co-Author: Nothing to Disclose

Francis Gerard Girvin MBChB, Abstract Co-Author: Nothing to Disclose

Jane P. Ko MD, Abstract Co-Author: Nothing to Disclose

Derek M. Mason MD, Abstract Co-Author: Nothing to Disclose

Maj L. Wickstrom MD, Abstract Co-Author: Nothing to Disclose

To assess the need for pre-contrast imaging when evaluating for Acute Aortic Intramural Hematoma (IMH). The current gold standard for the detection of Aortic Dissection (AD) is CT angiography. However, along the disease spectrum of AD, lie several related pathologies with near identical clinical presentations. IMH, one such disease, lacks an intraluminal flap or discernible communication between the luminal blood and the intramural hematoma. It has long been posited that concern for this pathology alone necessitated pre-contrast images (in addition to post contrast images) to conclusively rule out IMH (in addition to AD.) This study seeks to demonstrate non-inferiority to post-contrast imaging alone in comparison to pre- and post-contrast studies.

Study group of 23 patients (10M;13F;age 57-93;mean:78.5y) who underwent Pre- and Post-Contrast CT series and were diagnosed with IMH via official radiology report at a tertiary care hospital between 2007 – 2011. 23 gender and age controlled subjects were selected with no remarkable findings on CT. Five independently operating thoracic radiologists (dedicated experience in specialty 5-14 years) were presented with randomized, anonymized post-contrast imaging alone of the 46 above patients, aware of suspected acute aortic injury, and asked to comment on the absence or presence of IMH, AD, and/or penetrating ulceration. They were then presented with both the Pre- and Post-Contrast series for these patients and asked for their diagnoses yet again.

Within the post-contrast group, the readers were diagnostically accurate for IMH 72.8% of the time, as opposed to the combined pre- and post-contrast group, where they were accurate 76.8%. (p-value .340). ( 95% CI -2.2⇔8.8.) Since the difference between the 2 groups was statistically insignificant and it can be asserted with 95% confidence that no greater than 8.8% of cases of IMH would be missed with post-contrast imaging alone, post-contrast imaging alone was statistically non-inferior to combined pre- and post-contrast imaging. .

IMH is radiographically evident on post contrast imaging alone and it is statistically non-inferior to combined pre- and post-contrast sequences.

In clinical practice, when evaluating for possible aortic syndromes (Dissection, IMH, etc.) we contend that post-contrast angiography alone may suffice. Broader/confirmatory study may be warranted.

Portnoy, E, Shiau, M, Babb, J, Weiner, R, Girvin, F, Ko, J, Mason, D, Wickstrom, M, Is the Precontrast CT Series Necessary for Ruling Out Acute Aortic Intramural Hematoma?.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13013336.html