[Brain 3 D-CT angiography was a useful tool for diagnosis of internal carotid-posterior communicating artery aneurysm: a case of false negative 3 D-MRA].
A 75-year-old woman with hypertension suddenly developed ptosis in the left eyelid. Neurological examination revealed left oculomotor nerve palsy. Brain T 2-weighted imaging showed abnormal flow void sign in the proximal portion of left middle cerebral artery. Other MRIs, including gadolinium enhancement, were normal. However, brain 3 D-MRA, using time-of-flight sequence, did not disclose any intracranial aneurysms. 3 D-CT angiography revealed left internal carotid-posterior communicating artery (IC-PC) aneurysm. Maximum intensity projection display of CT angiography demonstrated the neck and head portions of IC-PC aneurysm (size = 8 mm). Furthermore, 3 D-CT angiography was beneficial for anatomical evaluation of the aneurysm and the surrounding bony structures. The false negative 3 D-MRA of our patient was thought to result from flow-related artifacts, slow blood flow in the aneurysm, the surrounding noise and the localization of aneurysm. False negative findings of cerebral aneurysms occasionally occur on 3 D-MRA or 3 D-CT angiography, in comparison with digital subtraction angiography. Thus, we should pay more attention to assessment of 3 D-MRA and 3 D-CT angiography in patients who have high risks of cerebral aneurysms.
Ikeda
K
K
Fourth Department of Internal Medicine, Toho University Ohashi Hospital, Tokyo, Japan.
Iwasaki
Y
Y
Murakami
S
S
Ichikawa
Y
Y
D000368:Aged; D002340:Carotid Artery Diseases / Q000175:diagnosis*; D002343:Carotid Artery, Internal; D002533:Cerebral Angiography / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000175:diagnosis*; D018810:Magnetic Resonance Angiography / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*