Retrospective Comparative Analysis of Computed Tomography Findings of Acute and Chronic Aortic Dissections and Intramural Hematomas

Abstract

Purpose: The objective of this study was to assess the reliability of ancillary imaging findings in distinguishing acute from chronic aortic dissection (AD) and intramural hematoma (IMH) using computed tomography angiography (CTA). Materials and Methods: Two radiologists specializing in cardiothoracic and vascular imaging reviewed paired CTAs of patients with AD or IMH who underwent CTA in the acute (within 24 h of presentation) and chronic settings. The radiologists were blinded to the temporal order of the CTAs. Minimum and maximum flap thicknesses and presence or absence of pleural effusion, pericardial effusion, mediastinal hematoma or fat standing, and mediastinal lymphadenopathy were recorded. Results: Patients included 25 male individuals and 13 female individuals with a mean age of 59 years (range: 34 to 87 y). The group included 29 AD and 9 IMH cases. The median interval between the paired CTs was 542 days (range: 100 to 2533 d). Respectively, the mean minimum flap thicknesses in the acute and chronic AD were 1.3 and 1.4 mm (P=0.3), and the mean maximum flap thicknesses were 2.7 and 2.9 mm (P=0.29). The incidences of ancillary findings in acute and chronic AD and IMH were as follows: pleural effusion (55% vs. 37%, P=0.143), pericardial effusion (8% vs. 11%, P=1.0), lymphadenopathy (47% vs. 47%, P=1.0), and periaortic fat stranding (87% vs. 76%, P=0.344). Conclusions: Ancillary CT imaging findings traditionally ascribed to acute AD and IMH are also often found in the chronic setting and are not reliable indicators of acuity. Flap thickness in AD may not be a reliable imaging indicator of acuity of AD.

Diagnostic value of dynamic computed tomographic angiography for aortic dissection and the perfusion of involved organs

“…AD patients, mainly the elderly, often have combined atherosclerosis and aortic vascular changes, and as a result, the aortic blood circulation resistance increases, resulting in hemodynamic change [24]. Single-phase scanning may be disrupted by these hemodynamic changes and not detect the true and false lumens, whereas multiphase aorta CTA scanning can determine the number of tears, and false lumen ow can be observed by looking at different scan periods for a change in the true and false lumen contrast agent, providing favorable imaging data for clinical treatment [25][26][27]. Dynamic CT imaging technology can be applied to vascular imaging and AD after multiphase phase reconstruction, and each level can provide multiple static images of the phase at different periods.…”

Aortic intramural hematoma and classic aortic dissection: two sides of the same coin within the acute aortic syndrome for an interventional radiologist

“…In addition, CT provides important prognostic information when measuring parameters like the maximum haematoma thickness (MHT) and the maximum aortic diameter (MAD) 1 or evaluating “ancillary findings”. 3 Drawbacks are high radiation-doses, contrast-induced nephrotoxicity and artefacts from motion or beam hardening. Thus, several MRI techniques were developed, from the traditional time of fight (TOF) and phase contrast (PC) to the newest cardiac-gated 3D fast-spin-echo, arterial spin labelling and balanced steady-state free-precession; new contrast-enhanced techniques include time resolved imaging of contrast kinetics (TRICKS) MR angiography (MRA).…”

“… 7 The rationale of TEVAR is to exclude and favour the thrombosis of the false lumen; it seems that the earliest it is performed, the higher the likelihood of fully re-expansion of the true lumen. 3 Complications include graft obstruction, migration, infection, stroke/paraplegia, visceral ischaemia, endoleak or retrograde aortic dissection. The latter, consisting in injury of the innermost layers of the aorta with subsequent blood flow between intima and media, is frequent in the immediate postoperative period and associated with a high mortality risk.…”

“…Finally, CT is employed for follow-up and potential complications. 3 However, high radiation-doses, risk of contrast-induced nephrotoxicity, motion and beam hardening artefacts still represent an issue. 4 Although the use of paramagnetic contrast material shortening the T1 relaxation time improves contrast between blood vessels and background, mural thrombi or/and calcifications are not well visible on MRI.…”

“…Technical success is around 98%, with need for secondary interventions in 3.6–4.4% and a 1.9–2.1% perioperative mortality (versus 5.7–11.7% of open repair) 7 ; prompt endovascular repair prevents aortic wall remodelling and is thus associated with a higher success rate. 3 The main complications include obstruction, migration (1 to 2.8%, associated with aortic tortuosity and graft oversizing), infection, endoleak (3.9 to 15%) and aortic dissection; the last one, in particular, seems secondary to the chronic radial force associated with the device (especially if oversized) and the subsequent thinning of the media. 10 Other major complications are stroke (4–8%, due to embolisation to the carotid artery, coverage of the left subclavian artery or embolisation via the subclavian), paraplegia (3–5.6%, due to spinal cord ischaemia) and visceral ischaemia (if the celiac artery origin is covered).…”