The relationship between the presence of a partial thrombus and aortic dilation after type B dissection has recently been reported. The originality lies in the idea of imaging thrombus activity to predict dilation after type B dissection. The innovative character is based on the use of annexin scintigraphy.

To establish the proof of concept in humans of the link between the intensity of 99mTc-annexin V-128 binding in the descending thoracic aorta and the progression of aortic diameter in patients with type B aortic dissection.

Inclusion Criteria:

• patient whose age is ≥ 18 years old
• any patient seen more than 6 months and less than 5 years after a dissection involving the descending aorta at Bichat Hospital, whether it is a dissection of the descending aorta alone or a dissection of the ascending aorta extended to the descending aorta
• dissection of the uncomplicated descending thoracic aorta: not requiring surgery or stent implantation within the first 6 months after acute dissection
• effective contraception for women of childbearing age

Exclusion Criteria:

• scheduled procedure for dissection of the descending aorta
• contraindication to aortic CT with injection of contrast media: renal failure with creatinine clearance <30 ml/min or creatinine >200 µmol/l; allergy to contrast media
• history of surgery or stent implantation in the descending thoracic aorta
• pregnant or breastfeeding women
• patient under guardianship or trusteeship
• non affiliation to social security or CMU (beneficiary or assignee)
• patient refusal to participate in the study