Investig Magn Reson Imaging.  2018 Dec;22(4):266-271. 10.13104/imri.2018.22.4.266.

Magnetization Transfer Contrast Angiography for Organized Thrombosed Intracranial Aneurysm in TOF MR Angiography: a Case Report

• Kang DH
• Lee HJ

• KMID: 2431113
• DOI: http://doi.org/10.13104/imri.2018.22.4.266

Abstract

A 66-year-old woman was referred for treatment of incidental detection of two intracranial aneurysms. Time-of-flight MR angiography (TOF MRA) revealed two aneurysms at the M1 segment of the right middle cerebral artery, and clinoid segment of left internal carotid artery, respectively. On digital subtraction angiography, there was a saccular aneurysm on the left internal carotid artery, but the other aneurysm was not detected on the right middle cerebral artery. Based on comprehensive review of imaging findings, organized thrombosed aneurysm was judged as the most likely diagnosis. In the presented report, magnetization transfer (MT) pulse to TOF MRA was used, to differentiate aneurysm-mimicking lesion on TOF MRA. We report that MT technique could be effective in differentiating true aneurysm, from possible T1 high signal artifact on TOF MRA.

Keyword

Aneurysm; TOF MR angiography; Artifact; Magnetization transfer

MeSH Terms

Aged
Aneurysm
Angiography*
Angiography, Digital Subtraction
Artifacts
Carotid Artery, Internal
Diagnosis
Female
Humans
Intracranial Aneurysm*
Middle Cerebral Artery

Figure

• 

  Fig. 1 66-year-old woman with a diagnostic pitfall on TOF MR angiography. TOF MRA (a) shows two intracranial aneurysms; one is located at the M1 segment of right middle cerebral artery (MCA; arrow) and the clinoid segment of left internal carotid artery (ICA; arrowhead). Aneurysm was invisible (arrow) digital subtraction angiography (b). In contrast, saccular aneurysm from the left ICA is noted on 3D Rotational angiography (c, arrowhead). The lesion at the vicinity of the right MCA shows high signal intensity (arrow) on T1 (d) and low signal intensity (arrow) on T2 weight MR image (e). High signal intensity lesions suggestive aneurysms (arrow) at the vicinity of right MCA (f) and ophthalmic segment of left ICA (arrowhead) (g) are noted on the source images of TOF MRA.

• 

  Fig. 2 Magnetization transfer contrast angiography. As compared with an aneurysm (arrow) on MToff (a), better conspicuity of lenticulostriate arteries (double arrows) is noted on MTon angiography (b). MTC subtraction MRA (c) as a result of subtraction of MTon (b) from MToff (a) shows no aneurysm (arrow) in the right middle cerebral artery, contrary to well definition of aneurysm (arrowhead) at right ICA.

• 

  Fig. 3 Phase shift TOF MRA (a: in-phase, b: out-of-phase) did not showed chemical artifact around small hyperintense lesion (arrows) in the right middle cerebral artery. Source image of magnetization transfer contrast MRA (c) shows low signal intensity of pitfall (arrow). MTR of pitfall (open arrow) (d) and true lesion (open arrow) (e) was 0.170 ± 0.230, and 0.421 ± 0.209, respectively. CT (f) shows high-density wall (Hounsfield unit = 134.2 ± 30.2) with relatively low-density core (arrow) (Hounsfield unit = 64.4 ± 20.2) on the center of lesion.

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