The differences and similarities between intramural hematoma of the descending aorta and acute type B dissection

J Vasc Surg. 2013 Dec;58(6):1498-504. doi: 10.1016/j.jvs.2013.05.099. Epub 2013 Sep 21. http://www.ncbi.nlm.nih.gov/pubmed/?term=the+differences+and+similarities+between+intramural+hematoma+of+the+descending IRAD investigators Aortic intramural hematoma type B (IMHB) VS type B aortic dissection (ABAD) IMHB was considered when a crescentic thickening of the aortic wall was identified on the first or second imaging study in the absence of any entry tear, double lumen, and/or intimal flap There was no difference in in-hospital mortality between the two groups. Periaortic hematoma was observed more often in patients with IMHB and was identified as a risk factor for rupture. Patients with ABAD had significantly more dilation of the descending aorta during follow up and more often had extension into the abdominal aorta than those with IMHB. IMHB may have a more indolent clinical course than ABAD. IMHって定義が難しい。日本で言えば、どちらもB型解離。割れ方（下行で三日月形か、同心円型か）の違い。同心円型のほうが予後がいいという話。