Comparison of preperfusion and postperfusion magnetic resonance angiography in acute stroke.
OBJECTIVE
The multimodal magnetic resonance imaging study in acute stroke includes perfusion-weighted imaging (PWI) after administration of contrast and magnetic resonance angiography (MRA). However, MRA may overestimate the degree of vessel obstruction caused by limitations to detect low flow states. Our aim was to determine the usefulness of a new fast imaging protocol combining classical MRA, PWI, and postperfusion MRA to improve the diagnostic management in acute ischemic stroke.


METHODS
We studied 31 patients with a middle cerebral artery (MCA) infarction within the first 12 hours from the onset of symptoms. All patients had an MCA stenosis or occlusion. The study protocol included a preperfusion MRA and a postperfusion MRA. Modified thrombolysis in myocardial infarction (TIMI) classification was used to assess the patency of vessels.


RESULTS
In 17 patients (group A, 55%), preperfusion MRA and postperfusion MRA accorded in the estimation of vascular status, whereas in 14 patients (group B, 45%) postperfusion MRA showed a better vascular flow than preperfusion MRA. The improvement in the depiction of flow was from a complete occlusion (TIMI I) to a partial occlusion (TIMI II) in 9 patients and from TIMI II to normal patency (TIMI III) in 5 patients. Thirty-six percent of the patients with suspected internal carotid artery occlusion in the preperfusion MRA showed flow in the intracranial internal carotid artery in the postperfusion MRA.


CONCLUSIONS
Postperfusion contrast-enhanced MRA can demonstrate arterial segments with low flow and avoid overestimation of vascular obstruction.
Service of Radiology, Unidad de RM-IDI, Hospital Universitari Doctor Josep Trueta, Girona, Spain. spedraza@retemail.es
Salvador
S
Pedraza
Yolanda
Y
Silva
José
J
Mendez
Luis
L
Inaraja
Joana
J
Vera
Joaquín
J
Serena
Antoni
A
Dávalos
D000208:Acute Disease; D000368:Aged; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D016893:Carotid Stenosis / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology / Q000503:physiopathology*; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016037:Single-Blind Method; D013997:Time Factors; D014463:Ultrasonography; D014654:Vascular Patency
D003287:Contrast Media