Table 10. Dissection (D) ASCOD Classification with Causality Grades [8].

A table was created representing the different causality grades as an underlying etiology of ischemic stroke as per a subcategory of the ASCOD classification [8]. 

ASCOD: atherothrombosis, small vessel disease, cardiac pathology, other causes, and dissection classification; MRI: magnetic resonance imaging; TOF-MRA: time-of-flight magnetic resonance angiography; CT: computed tomography; XRA: X-ray angiography; CTA: computed tomography angiography; MRA: magnetic resonance angiography; US: ultrasound.

The Causality Grades [8]	ASCOD Dissection (D) Disease Phenotypes According to Classification [8]
D1: potentially causal. A stroke caused by dissection can be a result of one of the following:	An arterial dissection demonstrated by a hypersignal on FAT-saturated MRI, autopsy, TOF-MRA, CT scans, increased arterial diameter.			A demonstration of an arterial dissection by an indirect demonstration or by less sensitive or less specific diagnostic test (XRA, echocardiography, CTA, MRA, US) like an arterial stenosis seen without demonstration of the arterial wall hematoma
D2: the causal link is uncertain. It is defined as potentially one of the following:	An arterial dissection diagnosed based on a suggestive clinical history like a past history of dissection or Horner’s syndrome.			If there is imaging evidence of fibromuscular dysplasia of a cerebral artery of an involved cerebral field present.
D3: the causal link is unlikely, but the disease is present. Defined as potentially one of the following;	There is kinking or dolichoectasia (elongated, distended, and tortuous cerebral arteries that may present with compressive or ischemic symptoms) without complicated aneurysm or plicature.			There are arteries not implicated in the current ischemia that have evidence of fibromuscular dysplasia.
D0: dissection is neither detected nor suspected. In order to rule it out, the following should be done:	A negative fat-saturated MRI.	A normal XRA.	There is a lack of clinical suspicion of dissection.	There are negative extra- and intracranial cerebral artery evaluations.	A negative cardiac evaluation.
D9: an incomplete workup done on the patient. Minimum workup needed to rule out dissection is:	In patients younger than 60 years and with no evidence of A1, A2, S1, C1, or O1, should undergo MRI or XRA within 15 days of symptom onset.