Contrast-enhanced MR angiography of the supra-aortic vessels in 24 seconds: a feasibility study

Abstract

A contrast-enhanced, gradient-echo 3D pulse sequence providing angiographic information in 24 s was tested in five healthy subjects and used prospectively in 21 patients for the investigation of the cervical arteries. Indications included suspected stenosis of the carotid (in 13), or vertebral arteries (in 1), carotid dissection (3), variants of the branches of the aortic arch (2) and extracranial carotid aneurysms (2). The results in all patients were compared with those of intra-arterial digital subtraction angiography (DSA). In patients with carotid stenosis, they were also compared with high-resolution 3D time-of-flight (TOF) MR angiography (MRA). Good quality MR angiograms of the neck vessels were obtained with the fast 3D sequence in 20 of the 21 patients. One claustrophobic patient was unable to cooperate. The degree of internal carotid artery (ICA) stenosis was graded correctly (compared to DSA) in 21 of 24 cases (87.5%). Two mild stenoses were overestimated as moderate using the fast MR sequence and one high-grade stenosis was misdiagnosed as a complete occlusion. Carotid dissection was confirmed in one case and correctly excluded in two. Four extracranial ICA aneurysms in two patients, arterial variants and stenosis of the origin of the vertebral artery were correctly diagnosed using the contrast-enhanced MR angiogram. Three-dimensional TOF MRA was unsuccessful due to motion artefacts in half of the cases of ICA stenosis.

High Resolution Contrast-Enhanced MR Angiography in the Evaluation of Rabbit Carotid Artery

“…In human, the mean time from brachial venous injection to arrival in the carotid artery was calculated as 15.7 seconds (range, 10-22 seconds) 18 . But the mean interval from peak carotid arterial enhancement to early jugular venous enhancement is only 7-8 seconds 16,18 . Appropriate timing and rate of contrast medium injection would avoid imaging too early or too late.…”

“…It will be beneficial to measure the diameter of carotid artery and calculate the percentage of artery stenosis. The quality of the contrast-enhanced MR angiography depends on the timing of the contrast medium bolus 15,16 . MR acquisitions started too early lead to an insufficient arterial enhancement with a central signal void, whereas a late start leads to enhanced venous and parenchymal structures that compromise CNR 17 .…”

Contrast-enhanced Magnetic Resonance Angiography in Stroke Diagnostics

“…Furthermore slow collateral flow over small leptomeningeal connections cannot be visualized by tOF-Mra [4,5,[9][10][11] and ce-Mra is superior to tOFMra in imaging of such pathologies. ce-Mra and DSa have a high correlation in the detection and classification of high grade stenosis and occlusion of extracranial segments of the internal carotid artery [8,[12][13][14][15]. For the detection of a high grade stenosis of the extracranial internal carotid artery the specificity is up to 100% and sensitivity is up to 93% [13].…”

Kann die Time-of-Flight-Angiographie in der MRT die präoperative Duplex- und Doppler-Untersuchung der Arteria carotis ersetzen? - Ergebnisse eines prospektiven Vergleichs mit Literaturübersicht

“…Die Weiterverarbeitung erfolgt als sekundäre 3D-MIP (Maximum Intensity Projection)-Rekonstruktion, SSD (surface shading display)-Oberflächendarstellung oder Volume-rendering-Technik (VRT Die Magnetresonanztomographie hat sich für die Diagnostik der extrakraniellen Erkrankungen der A. carotis etabliert, ihre Trennschärfe in der Unterscheidung zwischen chirurgischen und nichtchirurgischen Graden der Stenose zieht mit der des Ultraschalls gleich bzw. übertrifft diesen [9,10,11,14]. Der Standard ist zur Zeit die 3D-TOF-MRA, die sich nicht nur als akkurat in der Beurteilung des Grades der Stenose gezeigt hat, sondern es wurden auch viel versprechende Ansätze zur Charakterisierung der arteriosklerotischen Läsion publiziert [4,9,16,17].…”