Subarachnoid hemorrhage of unknown etiology

SIO

Cerebrovascular Disorders - Aneurysms

Conclusions: For the first time the prevalence of incidental las has been studied in three different risk groups in the defined geographical area. Our result confirms earlier reports, that in familial cases asymptomatic first-degree relatives have an increased risk for las compared to the other study groups. Screening and preventive treatment of las should be focused only in familial cases.

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0-3-3 2 1 Detection of unruptured cerebral aneurysms in healthy population and its significance for prevention of subarachnoid hemorrhage

Kazuo Hashi', ToshioNakagawa2 , Kahji Sait0 3 . ' Department of Neurosurgery, SapporoMedicalUniversity, Hokkaido, Japan, 2Shinsapporo Neurosurgical Hospital, Hokkaido, Japan, 3Kushiro Neurosurgical Hospital, Hokkaido, Japan Recentstudies have shown that the true incidenceof the SAH reaches approximately 100/100,000 population/year, in the case that the elderly population of over 50 years of age is counted. Likewise, a higherincidenceof the unruptured cerebral aneurysms (UCA) should be anticipated within the adult population. We performed screening studies using the MRA for UCA in healthy adult populations and confirmed the high incidence of UCA. The 3D-CTAwas used for confirmation. In our study of 840 individualswe found an incidence of the UCA of 5.8%. It was 7.4% in females and 5.0% in males. The incidence increased with age, but there was a peak in the 40s, suggesting a dual nature of UCA formation . Sixty percent of UCA were less than 5 mm in diameter. The family history of SAH was the sole significant risk factor with a risk of 12%. The operation for UCA outnumbered ruptured aneurysmssince this health check has been commenced. The morbidity was less than 2% with no mortality. A study in KushiroCity showed a decrease of the SAH in the recent3 years of oral along with a rapid increase of operations for UCA since 1992. Current status of the finding of an UCA in the healthy individual in Japan and its significance for the preventing of a SAH will be discussed.

I0-3-33 1 Efficacy of the brain documentation "(Brain Dock)" in prevention of subarachnoid hemorrhage Significance of screening the high-risk group with a family history of subarachnoid hemorrhage-

ToshioNakagawa' , Kazuo Hashi2 , SumiyoshiTanabe 2, AkinoriYamamura 1. 1 Shinsapporo Neurosurgical Hospital, Sapporo, Japan, 2 Department of Neurosurgery, Sapporo MedicalUniversity SChool of Medicine, Sapporo, Japan The importance of screeningpeople with a family historyof subarachnoid hemorrhage(SAH)within the seconddegree of consanguinity for preventing SAH is discussedin this report.The authors have reported significantly higherincidence of unruptured cerebral aneurysms shown in the "brain dock" volunteers with a family history of SAH within the same range and pointed out the necessity to recognize themas a high-riskgroup of possibleunruptured cerebral aneurysms. In the present study, 225 patients with a family history of SAH within the same range who were either admitted to our hospital or visited outpatients after May 1993 were investigated with respect to the incidence of possible unruptured cerebral aneurysms and its relation to the risk factors of arteriosclerosis. The subjectswere restricted to those who had no symptomsor historyof eitherSAH or cerebral aneurysms and in whom cerebral aneurysms were confirmed by cerebral angiography such as MRA, 3D·CTA, and IA-DSA. As a result, thirtyseven unruptured cerebral aneurysms were found in 30 cases (13.3%) among the subjects. Six of the cases showed mUltiple aneurysms (20.0%). The distribution of aneurysms was: 14 (37.8%) in the internal carotid artery, 16 (43.2%) in' the middle cerebral artery, 3 (8.1 %) in the anterior communicating artery, 2 (5.4%) in the basilarartery,and one (2.7%) in boththe vertebralarteryand distal arteriorcerebralartery. As to the relationship between familyhistoryof aneurysm and the discoveryrate, aneurysmswerefound in 13 out of 109 (11 .9%) patients witha historyof aneurysmsin parents,in 15of 95 (15.8%) patientswith a history in siblings, 0 of 6 (0%) patients with a history in grandparents, and in 2 of 15 (13.3%) patients with multiple family history. As for the relationship between risk factors and incidenceof aneurysms, hypertension wasassociated in 20.6% of the cases, diabetes mellitus in 28.6%, hyperlipidemia in 26.3%, smoking in 14.3%, multiple risk factors in 30.4%, and aneurysms were detected in 9.9% of the patients with no risk factors and in 12.5% with cerebral infarction. Thus a high incidence of unruptured cerebral aneurysms was found in cases with a family history of SAH within the second degree of consanguinity as found in the brain dock volunteers. Such cases can be defined as a high-risk group and aggressive screening for cerebrovascular disease, as well as detailed examination, for this group is very importantand could improveSAH prevention, particularlyfor those who have multiple risk factors.

Monday, 7 July 1997 I 0-3-3 4 1

Subarachnoid hemorrhage of unknown etiology

Zoran Milenkovic 1 , StojankaDjuric 2 , AleksandarIgic ' , Rade Mitic 1 , Jelena Stamenoyic 2 '. Milorad Babic1 . 1 Neurosurgical ClinicMedical School, Universityof Nlf!, Nlf!, Yugoslavia, 2 Clinicof Neurology MedicalSchool, UniversitY of NIS, NIS, Yugoslavia Thediagnosisof spontaneous subarachnoid hemorrhage (SAH)alertsthe physi· clan to the possibility of a potentially life-threatening condition. Approximately 80% of patients with a spontaneous SAH will tum out to have an intracranial aneurysm or an intracranial AVM. Subarachnoid hemorrhage is also a well-recognised elementof severaldiverse medical complications or diseases. Acknowledging these rare causes of SAH, 7-27 percent of patients who have suffered SAH will demonstrate no source of such hemorrhage. In a series of 413 patients with signs and symptoms of SAH, 80 patients had SAH of an unknownetiology. The dominant symptomswere sudden attacksof headaches and vomiting; the majorityof patients were femalesin a HunVHess clinicalgrade lor II; computed tomography scan revealeda high percentage(34.21%) of patients who had no discernible subarachnoid blood visible on a postictal brain CT scan. There was no recurrent hemorrhage among our patients. All patients were treated by bed rest, hydration, antiedematous therapy and some of them received nimodipin. There was one death unrelated to the stroke and low morbidity. So one can concludethat patientswith SAH of an unknownetiologyhave a markedlybetterprognosisthan patients with a ruptured intracranial aneurysm.

I0-3-35 1 Three-dimensional CT angiography (3D-CTA) for cerebral aneurysms

Masayuki Nakano, Yuji Endo, ToruKobayashi, YeichiWatanabe, MasatoMatsumoto, NamioKodama. Department of Neurosurgery, Fukushima Medical School, Fukushima, Japan The accuracy, usefulness and problems of 3D-CTA in detecting aneurysms is discussedin comparison with angiography. One hundred and seven patients with subarachnoid hemorrhage in 55 patients and screeningin 52 were examinedby CT, angiogramand 3D-CTA. ACT systemwas X vigor" (Toshiba Medical Co. 135kV, 200mA.) The slice thickness was 1.0 mm. Helical CT scan was performed using an injection of non-ionic contrast material via the antecubital vein at the rate of 3 to 2 mils for 90 ml, with 20 seconds scan delay. 3D-CTA was created using Healrender" (Toshiba Medical Co.) from zoomedimage. Totalnumberof aneurysms was 84. Eighty two out of 84 aneurysms(97.6%) weredemonstrated by angiography, and these82 aneurysmswerealso detected by 3D-CTA. Although2 aneurysms were not demonstrated by angiogram, one of them was detected by 3D-GTA. It was an unruptured aneurysmand the size was about 0.8 mm in diameterconfirmedby surgery. Whilethe secondone was neither detected by angiogram nor 3D-CTA. It was confirmed by surgery and its size was 0.5 mm in diameter. The sensitivity of 3D-CTA was 98.8%. The 3D-CTA gave us useful information concerning the anatomical relationship of the aneurysm, its neck and parent artery, and the surrounding branches. The problems were as follows; poor visualization of small arteries less than 1 mm and aneurysm covered with bony structures, difficulty of distinction between arteriesand veins. The accuratedetection of cerebral aneurysmsby 3D-CTAwas thought to be the sameas by angiography, and 3D-CTAwas usefulfor surgicalslrnutatlon. We think it is possible to plan and perform surgery without angiography in limited cases. It is necessary to develop the hardware and the software for resolving the problems.

I0 -3-36 1 CT-angiography Diagnostic imaging in neurovascular surgery: Will replace digital substraction angiography? J. Hamacher 1, H. Fischer2 , E. uns" , J.C.w . Kiwit' . 1 Neurochirurgische Klinik, Medizinische Einrichfungen d, Heinrich-Heine UniversifijtDiisseldorf, Germany, 2/nslitut far Diagnostische Radiologie der Heinrich-Heine Universitiit Dusseldorf, Germany Introduction: The"goldstandard" in assessing number, configuration andblood supply pattern in cerebral aneurysm is digital substraction angiography (DSA) at present. Methods: We conducted a retrospective study of 50 patientswith CT proven subarachnoidal hemorrhage (SAH) in our department to compareCT-angiography and DSAwith regardto aneurysm detection, flow patterns and morphological appearance. All cases within a one year period were included (X/95--X/96). Particularattention was drawn to the morphological appearance and flow patterns of partiallyor totally thrombosed aneurysms. Results: All aneurysms of anterior and posteriorcirculationcould be clearly identified on CT-Angiography. On DSA however, one aneurysm could not be identified, the CTA clearly showing the aneurysm origin. By rotating the CTA·