TABLE 30.

High-Risk Imaging Features of IMH

For Type A IMH	For Type B IMH
■ Maximum aortic diameter >45–50 mm18,20	■ Maximum aortic diameter >47–50 mm15,20
■ Hematoma thickness ≥10 mm4	■ Hematoma thickness ≥13 mm15
■ Focal intimal disruption with ulcer-like projection involving ascending aorta or arch18,21	■ Focal intimal disruption with ulcer-like projection involving the descending thoracic aorta if it develops in acute phase15,16
■ Pericardial effusion on admission18	■ Increasing or recurrent pleural effusion19,22
For Both Type A and Type B IMH
■ Progression to aortic dissection19
■ Increasing aortic diameter21,22
■ Increasing hematoma thickness21,22

IMH indicates intramural hematoma.