MORPHOLOGICAL DIFFERENCES BETWEEN RUPTURED AND UNRUPTURED CASES IN MIDDLE CEREBRAL ARTERY ANEURYSMS

OBJECTIVETo elucidate the morphological differences between ruptured and unruptured aneurysms, three-dimensional digital subtraction angiography was performed in 44 cases (20 unruptured, 24 ruptured) of middle cerebral artery aneurysm. METHODSWhen the neck was located on the extension of the midline of the parent artery, it was defined as Type C; when it was not, it was defined as Type D. Aspect ratio (AP ratio; dome/neck ratio) and daughter artery ratio (DA ratio; diameter of the larger daughter artery/diameter of the smaller daughter artery) were calculated, and these ratios were compared for ruptured and unruptured cases. RESULTSNineteen cases were Type C and 25 cases were Type D. χ2 test revealed that there were significantly more ruptured cases among Type C (14 out of 19) compared with Type D (10 out of 25) (P < 0.05). AP ratios were 2.24 ± 0.75 for ruptured cases and 1.56 ± 0.58 for unruptured cases. DA ratios were 1.53 ± 0.54 in ruptured cases and 2.14 ± 0.80 for unruptured cases. Both showed significant differences (P < 0.01). In cases with an AP ratio of 1.8 or greater and a DA ratio less than 1.7, 13 out of 15 (87%) were ruptured cases. On the contrary, in cases with an AP ratio less than 1.8 and a DA ratio of 1.7 or greater, 12 out of 13 (92%) were unruptured cases. CONCLUSIONType C and equality of the diameters of two daughter arteries, together with high AP ratios, seem to be morphological factors that associate with aneurysmal rupture.

[1]  Kaoru Kurisu,et al.  Evaluation of relation among aneurysmal neck, parent artery, and daughter arteries in middle cerebral artery aneurysms, by three-dimensional digital subtraction angiography , 2005, Neurosurgical Review.

[2]  N. Kassell,et al.  Cigarette smoking as a cause of aneurysmal subarachnoid hemorrhage and risk for vasospasm: a report of the Cooperative Aneurysm Study. , 1998, Journal of neurosurgery.

[3]  H. Handa,et al.  Cigarette Smoking , Hypertension and the Risk of Subarachnoid Hemorrhage : A Population-Based Case-Control Study , 2005 .

[4]  A. Roses,et al.  Risk of Intracranial Aneurysms in Families With Subarachnoid Hemorrhage , 1995, Canadian Journal of Neurological Sciences / Journal Canadien des Sciences Neurologiques.

[5]  Kaoru Kurisu,et al.  The characteristics of the anterior communicating artery aneurysm complex by three-dimensional digital subtraction angiography , 2006, Neurosurgical Review.

[6]  P. Spiegel,et al.  Intracranial aneurysms. Age, sex, blood pressure, and multiplicity in an unselected series of patients. , 1979, Journal of neurosurgery.

[7]  K. Takayama,et al.  A proposed parent vessel geometry-based categorization of saccular intracranial aneurysms: computational flow dynamics analysis of the risk factors for lesion rupture. , 2005, Journal of neurosurgery.

[8]  S. Juvela,et al.  Cigarette Smoking and Alcohol Consumption as Risk Factors for Aneurysmal Subarachnoid Hemorrhage , 1993, Stroke.

[9]  L N Sekhar,et al.  Origin, growth, and rupture of saccular aneurysms: a review. , 1981, Neurosurgery.

[10]  J Max Findlay,et al.  The aspect ratio (dome/neck) of ruptured and unruptured aneurysms. , 2003, Journal of neurosurgery.

[11]  A. Mendelow,et al.  Unruptured intracranial aneurysms: benign curiosity or ticking bomb? , 2004, The Lancet Neurology.

[12]  S. Juvela,et al.  Factors Affecting Formation and Growth of Intracranial Aneurysms: A Long-Term Follow-Up Study , 2001, Stroke.

[13]  C. Putman,et al.  Characterization of cerebral aneurysms for assessing risk of rupture by using patient-specific computational hemodynamics models. , 2005, AJNR. American journal of neuroradiology.

[14]  C. Ogilvy,et al.  Stratification of Outcome for Surgically Treated Unruptured Intracranial Aneurysms , 2003, Neurosurgery.

[15]  M. Ryynänen,et al.  Familial subarachnoid hemorrhage in east Finland, 1977-1990. , 1993, Neurosurgery.

[16]  D. Nichols,et al.  Unruptured intracranial aneurysms: natural history, clinical outcome, and risks of surgical and endovascular treatment , 2003, The Lancet.

[17]  A. Nanda,et al.  Intracranial aneurysms and cocaine abuse: analysis of prognostic indicators. , 2000, Neurosurgery.

[18]  T. Hori,et al.  Is the Aspect Ratio a Reliable Index for Predicting the Rupture of a Saccular Aneurysm? , 2001, Neurosurgery.

[19]  G. Ferguson.  Physical factors in the initiation, growth, and rupture of human intracranial saccular aneurysms. , 1972, Journal of neurosurgery.

[20]  B. Reiser,et al.  Estimation of the Youden Index and its Associated Cutoff Point , 2005, Biometrical journal. Biometrische Zeitschrift.

[21]  C. Metz.  Basic principles of ROC analysis. , 1978, Seminars in nuclear medicine.

[22]  S. Juvela,et al.  Hypertension and aneurysmal subarachnoid hemorrhage. , 2002, Wiener klinische Wochenschrift.

[23]  Marko Kangasniemi,et al.  Remodeling of Saccular Cerebral Artery Aneurysm Wall Is Associated With Rupture: Histological Analysis of 24 Unruptured and 42 Ruptured Cases , 2004, Stroke.