Abstracts

Journalof

Neurology © Springer-Verlag 1990

J Neurol (1990) 237 : 501-506

Annual Meeting of the Austrian Society of Neuroimaging held in Linz, Austria 17 November 1990

Chairpersons: F. Aichner and E. Deisenhammer

REPRODUCIBILITY OF HMPAO - BRAIN UPTAKE I. Podreka, S. Asenbaum, T. Brucke, S. Wenger, W. Lang, G. Go[denberg, M.

chmidbauer. L. Deecke bis study was undertaken in order to investigate, if quantitative data on

CBF can be obtained in the same subject from HMPAO-SPECT investigations.

Repeated SPECT studies separated by 8.6 ± 4.4 days were performed in 17 subjects 49.6 * 16.9 years of age (5 normals, 12 patients wim peripherie neurologieal or chronic CNS diseases) . After system calibration (dual headgamma camera), counts in SPECT slices could be converted into Ci. For global HMPAO-uptake estimation, pixels of single slices (3.125 mm thick) which contalned 36% or more of the maximal pixel content were summed together. Multiplication of the pixel sum by the pixel volume gare the brain säze in tal. HMPAO-uptake was then expressed in % of the injected dosis/100 ml braln tissue. For regional HMPAO-uptake evaluation a total of 17 ROIS/hemisphere, covering predominantly gray marter, were drawn on 4 adjacent 21.9 mm thick transversal sections. Correlation and regression analysis was used for statistical evaluanon.

Global and hemispheric HMPAO-uptake values were highly repro- dueible (r=0.957, r=0.947, r=0.955 respective[y, all p < 0.001). %- difference of global HMPAO-uptake in the two measurements was 0.167 ± 6.0%, for the leff hemisphere 0.615 ± 6.7% and 0.493 i 6.3% for the fight hemisphere. Regional correlation coefficients were all significant (r=0.881 to r=0.973, all p < 0.001). However %-difference varied between 6.7% and 25.2% through the regions. The highest variation was recorded in smalf ROIS over the central or mesiotemporal cortex or the thalamus.

As out data show, calculation of %-HMPAO brain uptake from SPECT images is reproducible. The best results were obtained, as expected, for global and hemispheric tracer uptake. The maximal difference between two studies was 12.7%_ which is also known to be for PET studies sej3arated by 1-8 days. The ROI size, cortical atrophy, as well as the shght variations in re~ositioning of the subjects were mostly responsible for regional uptake dlfferences. Considering these res•lts, the described method can be used routinely for the approximative calculafion of intraindividual CBF changes caused by drugs or by neurophysiological stimul~zion.

Neurologische Uruversitätsldinik Wien, Lazarettgasse 14, A-1090 Wien, Osterreich.

BRAIN SPECT USING A BENZODIAZEPINE(BZD)-RECEPTOR-LIGAND (IOMAZENIL)

Deisenhammer E., Diem R., $chuber P.A., Brucker B.

Specific receptors are thought to mediate the various pharmacological effects of BZD administered for therapeu- tic purposes. These receptors may either be changed reversibly in hepatic encephalopathy and seizures or altered irreversibly in degenerative disorders. BZD receptors were imaged by SPECT with fomazenil (I). After i.v. injection, the initial regional uptake in the brain tissue depends on regional blood flow. Later, regional distribution of BZD receptors. A SPECT study done within a period of 15 minutes post i.v. injection of I therefore permits tomographic imaging of regional blood flow in analogy to other CBF markers. A delayed SPECT scan performed 120 minutes post injection shows the distribution of receptors. This justifies using I for the imaging of rCBF and doing a delayed scan for the imaging of receptors. The tracer was used for diagnostic purposes in different neurological diseases including epilepsy. A total of 72 patients were investigated; in 56 of them, a SPECT study using a different CBF marker was done within a few days. The $PECT of hypoactive lesions in the various diseases obtained by the initial study with I the delayed study with I and the study with another CBF marker showed no essential differences. So far SPECT studies in various diseases have not furnished any additional information beyond the results obtained with other CBF markers.

Wagner-Jauregg-Krankenhaus A-4020 Linz, Anstria

502

SPECT IMAGING OF CNS D-2 DOPAMINE RECEPTORS IN BRAIN: PRELIMITARY RESULTS AND THE DIAGNOSTIC VALUE.

P. Költringer, P~Lind, F.Reisecker, WJ_,angsteger, O.Eber Barmherzige Brüder Hospital Graz-Eggenberg, Austria. During more than one decade neuroreceptor imaging has been reserved for PET investigations only. In vivo D2 dopamine receptors studies using PET were invest igated due to the availabil i ty of various radiolabel led antagonists of the neuroleptic family such as spiperone, raclopride or lisuride derivates. To enhance the possibi l i ty of D2 receptor studies the PET ligand bromolisuride was translated into a SPECT ligand, iodolisuride by replacing bromine-76, a positron emit t ing radiohalogen, with iodine-123. It was the aim of our pilot study, to compare own investigafions with results from the literature and so to evaluate the question for diagnost ic possibil i t ies and features of this new method. 5 subjects suffering from different forms of Parkinson disease were chosen for init ial studies in our hospital. For the D2 receptor imaging with SPECT 5 mCi of the radio iodoligand 3-iodo-2-hydroxy-6- methoxy-N-[(1-e thyl) -2-pyrrol id inyl)methyl lnezamide (IBZM) were injected intravenously after administrat ion of sodium perchlorate to prevent a possible uptake of radioiodine by the thyroid). Tomographic images of the intracerebral distribution if the radioact ivi ty were obtained after 15 minutes. 2 hours post injection the uptake was determined. For imaging a conventional rotat ing gamma-camera was used. As descr ibed in the literature in all patients an increase of uptake in the basal gangl ia could be observed. In two patients there were side differences of the uptake correlating to side differences, in symptomalogy of Park inson ' s disease. Concer ing to the literature and to out own pilot study the results seem to be interest ing but also problematical , because of the fact, that an absolute quantif icat ion of SPECT is still impossible. Nevertheless D2 receptor imag ing shows indeed a new method and a very interesting aspect, but at the moment without cl inical or diagnostic extension.

SPECT in migra ine , i n t e r l c t a l and i c t a l i n v e s t i g a t i o n s B.Brucker , E.Deisenhammer» Wagner-dauregg-Krankenhaus

Linz

~ECT studies with ~AO and I ~ permit an approximate evaluation of regional cerebral blood-flow (rCBF) and - as long as rCBF is iLnked to cerebral metabolism - also of regional metabolism. Performing SPECT in migraine patients with and without aura we found characteristic patterns of tracer distribution:

I. Increased tracer uptake in multiple small cortLca! and subcortical areas (patchy-pattern)

2. Large area of increased uptake 3. Decreased tracer uptake in the te~~oro-occipital cortex, mostly

symnetrical 4. Large areas with severely decreased tracer uptake (defects) 5. SHght side differences of larger circumscribed cortical segments

These results were obtained in 8 patients with/ and 13 without aura, p a t c h y ~ in 8/Io cases, extended increase of tracer uptake in I/3 cases, bi lateral te~~ooro-occipital decrease of uptake in 6/11 cases, defect in 3/o cases, minor cort ical side difference m I/2 cases. Several patterns, including defects, were seen during attacks with aura, more or less disappearing in the inter ictal state.

Discussion: Though individual patterns being non specific and the i r T n ~ i o n scmetimes being speculative, the ccmbination of uptake patterns are typical in migraine patients. Patchy-pattern may be indicative of small circu~scribed metabolic disturbances. Te~l~oro- occipital decrease of tracer uptaKe may ref lect the vulnerabi l i ty of this region in migraine. Circumscribed decrease, especiaily i f i t disappeares after the attack, is t probably the expression of circLmscribed perfusion-disturbance. An extended circunscribed increase of uptake may be only a variant of the patchy-pattern. The combination of patchy-pattem and te~T~ro-occipital decrease of tracer uptake seem to be pathognomonic for migraine.

A PRACTICAL METHOD FOR THE MATCHING OF FUNCTIONAL SPECT IMAGES AND MORPHOLOGICAL MRI INFORMATION R. Stollbergcr, F. Fazekas, F. Paycr, E. Flooh, H. Valetitsch, H. O f f e n b a c h e r

Emission tomographic studies of the brain such as SPECT and PET are able to provide important functional and biochemical in fo rmat ion . P rob lems in the iden t i f i ca t ion of under ly ing normal and pathologic anatomic structures increasc inverse to r e so lu t i on , however , and cons t i t u t e a se r ious d r a w b a c k espec ia l ty in SPECT. We therefore developed a method for supplement ing SPECT perfusion images by the anatomic details de r ived from MRI. In order to inc lude in fo rma t ion on pa thologic brain morphology as weil , we chose a techniquc applicable to T2-weighted MRI scans. In our procedure we perform the SPECT study first thereby mark ing a plane paral le l to the subsequent images on the patient. Before the MRI study we apply landmarks vis ible on the MRI scout view at these locations. This enables us to obtain MRI scans exac t ly match ing the SPECT angulat ion. In the p o s t p r o c e s s i n g phase an in -p lane m i s m a t c h is t cor rec ted t h r o u g h l i n e a r t r a n s f o r m a t i o n a f t e r a p p r o p r i a t e i m a g e p repa ra t i on . This cons i s t s m a i n l y of a con tu re f i nd ing algori thm based on segmentat ion of the MRl- images into three c lasses and subsequent conture detection. Due to l imited efforts for both exact pat ient posi t ioning and image p o s t p r o c c e s i n g this approach appears to be very prac t ica l . Moreover , it exc ludes poss ib le inaccura t c i e s of match ing techniques using only pos tprocess ing procedures.

M a g n e t - R e s o n a n z G r a z , M e d i z i n i s c h e P h y s i k und Neurologische Klinik, Auenbruggerplatz 9, A-8036 Graz

HMPAO-SPECT IN PATIENTS WITH CEREBROVASCULAR DISEASE - AN ATI'EMPT TO EVALUATE NEUROSURGICAL TREATMENT S.Asanbaum, I.Podreka, B.Schuster, T.Czech The employment of the SPECT-teclmique in diagnosing, quantifying and observing the course of cerebrovascular disease (CVD) has been repeatedly described. The alm of this study was not only to demonstrate the extent of CVD, but also to investigate the effect of distinct vessel operations on the regional cerebral blood flow (rCBF). At present 9 patients (mean age: 62 a, 5 men, 4 women; 6 patients with an occlusion of one internat carotid artery after an ischaemic incident, three patients with an arteriovenous malformation) have been examined repeatedly with HMPAO-SPECT. In order to test cerebrovascular reactivity two SPECT studies were performed before surgieal troatment (6 external-internal arterial bypass, 3 embolisations), one without and the second with Diamox (lg) i.v. admi,i~tration one week later. The first examination took place on average 4 weeks (2-12 weeks) after the appearence of last clinical symptom. Approximately 3 months after the operation a third SPECT investigation was carried out. SPECI' results were first examined visually. Then the global and hemisphoric HMPAO uptake, calculated as % of injected dosis per 100 ml of brain tissue, were determined. A ratlo was estimated between % HMPAO uptake in 3 cortieal reglons of interest (ROI; 1 focal in the defect area, 2 in the penumbra zone) and the contralateral hemisphere. In addition defects of the brain tissue were expressed by % of total brain volume. The caleulation of the HMPAO brain uptake showed a significant global as weil as hemispheric inerease after Diamox in comparison to the frrst examinatlon (p<0.001, t=-4.851). In opposite the calculated regional uptake ratios in the defmed ROIs deereased with Diamox, although not significantly. -After the EIA- bypass as weil as after the embolisation no significant ehange in the global or hemispheric HMPAO uptake (p<0.16) could be found. But the evaluation of the regional uptake ratio indicated a significant increase (p<0.03, t=3.193) of isotope uptake in orte penumbra zone (posterior to the defect). The size of the defect did not change. -No alteration could be found after embolisation. The neurological symptoms improved in three patients after an EIA, whereby no eommon changos in the calculation of the uptake were evident. Orte patient deteriotated clinically as well az in the extent of the cerehral defect, two remained unchanged. After AVM-embolisation, in orte patient an enlargement of the defect could be detected without appearanee of new neurological symptoms. So regardless of the elinical success of an EIA, a global increase of HMPAO uptake with a deerease in dcfect area and the penumbra zones after Diamox could be found praeoperaavly. After the operation a better tracer deposition was recorded in the penumbra zone at the site of the bypass. -The SPECT investigations after embolisaUons showed no significant changes.

Neurological Clinic of Vienna, Lazarettg.14, 1090 Vienna, Austria

SPECT STUDIES IN ACUTE HEMICHOREA CAUSED BY TRANSIENT CAROTID ISCHEMIA - A CASE REPORT

Leblhuber F, Brucker B, Trenkler J, Deisenhammer E Wagner-Jauregg-Krankenhaus, A-4020 Linz

In most cases of paroxysmal dyskinesias, charac- terized by repetitive involuntary movements, the cause of the abnormal movements is cerebrovas- cular disease. Most of these patients were trea- ted surgically, but few of them had successful treatment with antiplatelet therapy. We report the case of a 94 year old woman with a history of coronary artery disease and diabetes. Following anesthesia, she started having disa- bling paroxysmal hemichorea of her left extre- mities and facial dyskinesias. EEG was within broad normal limits, her blood chemistry was negative. CT scanning showed global atrophy without any focal lesion. SPECT scanning perfor- med before onset of therapy with aspirin showed distinct hyperactivity of the right striatum and hypoperfusion of the right corona radiata con- tralateral to the hyperkinetic symptoms. Two days after starting with i000 mg aspirin hemi- choreatic symptoms ceased, supporting the trial of aspirin prior to carotid surgery, especially in high risk patients. A control SPECT displayed symmetrical basal ganglia. There are various interpretations of the above mentioned lateralised hyperactivity of basal ganglia, the most probable cause is an interrup- tion of the cortico-striato-cortical feedback loop caused by transient ischemia.

503

MODELS AND 3 D VISUALIZATION OF BRAIN- AND SKULLTUMOUR AND SEGMENTS OF THE VERTEBRAL CANAL, DERIVED FROM CT SCANS

K. Heimberger, N. Pfafflmeyer, P. Samec, P. Solar, E. Schindler, P. Vierlinger

CT data have been used for two-dimensional reformattings of three-dimensional anatomical structures. Endoplan is a system comprising hard- and software which interactively creates a threedimensional reproduction of a CT scanned neuroanatomical structure as a model or as a computer generated monitor view, turning around an axis. The Endo- plan system is based on an HP300 computer and the MEK- processing software. The contours of the object to be visualized three-dimensionally, are defined by choosing the object's delineating Hounsfield density numbers manually or automatically. Models and video visualizations of two brain- and skull- tumours, and spine segments are demonstrated. 3 D visualization and models of neuroanatomic structures can be used for operative simulation and overlapping of morphological and functional neuroimaging.

Dept. of Neurology Vienna University Clinics, Lazarettgassè 14, A-I090 VIENNA AUSTRIA

Tc99-HMPAO SPECT IN BRAIN TUMOURS: A COMPARISON OF DYNAMIC AND STATIC DATA ACQUISITION H. Valeti tsch, F. Fazekas, F. Payer , G. Kle inen , H. Offenbacher , R. Kleinert and H. Lechner

T c 9 9 - H M P A O is a l ipophi l ic t r a ce r that r ead i ly c rosses the b lood b ra in ba r r i e r and is su f f ic ien t ly re ta ined the rea f t e r by c o n v e r s i o n to a more h y d r o p h i l i c c o m p o n e n t . T h e r e b y the pat tern o f d is t r ibut ion remains f ixed for a t ime long enough to be i m a g e d by c o n v e n t i o n a l s ta t i c s i ng l e p h o t o n e m i s s i o n computed t omography (SPECT). The mechan i sms of uptake and r e t e n t i o n o f T c 9 9 - H M P A O may be a l t e r ed in p a t h o l o g i c cond i t i ons , howeve r , thus no l onge r r e f l ec t ing t rue r eg iona l per fus ion rates. We therefore compared the results of dynamic da ta acquis i t ion s ta r t ing at the t ime of t r ace r in ject ion in a seiles o f 22 patients with brain tumours to those of static SPECT s c a n n i n g u s u a l l y p e r f o r m e d 2 0 - 3 0 m i n u t e s t h e r e a f t e r . A sys tem cons i s t i ng o f an a r ray of 4 r ap id ly ro ta t ing de tec to r b a n k s and a h igh sens i t iv i ty c o l l i m a t o r se rved to ob t a in suf f ic ien t coun t rates wi thin 2 minute intervals . 10 p a t i e n t s wi th g r a d e II-IV g l i o m a s exh ib i t ed p e r f u s i o n d e f e c t s on both d y n a m i c and s ta t i c s c a n n i n g . A r e a s o f inc reased t racer uptake present in the t u m o u r per iphery o f 4 o f these cases some t imes a p p e a r e d to be more obv ious by dynamic SPECT but remained more or less unchanged af ter two minu t e s of in jec t ion . Most m e n i n g i o m a s (4 o f 5 cases) in con t ras t turned out to be very act ive wi thin the f irst minutes o f d y n a m i c s c a n n i n g but showed no inc reased pe r fu s ion on stat ic SPECT. To some extent this was also true for p i tu i tary adenoms (2 cases) while there appeared to be even a defect o f t r a c e r u p t a k e in 2 p a t i e n t s w i th an a r t e r i o v e n o u s m a l f o r m a t i o n on s ta t i c s c a n s in c o n t r a s t to a m a r k e d hyperac t iv i ty within the first 4 minutes o f the dynamic s tudy. Our resul ts sugges t a f requent mi sma tch be tween t rue per fu- s ion and the t r ace r d i s t r ibu t ion pa t t e rn r evea led by s ta t ic S P E C T i m a g i n g and ind i ca t e use fu l add i t i ona l i n f o r m a t i o n provided by dynamic da ta acquis i t ion.

N e u r o l o g i s c h e Kl in ik und P a t h o l o g i s c h e s Ins t i tu t der Kar l - F ranzens Univers i tä t Graz , Auenbrugge rp l a t z , A-8036 Graz

NMR-SPECIROSCOPY OF THE CNS IN NEUROLOGIC DISORDERS

S. Felber, F. Aichner, G. Birbamer, A. Kampfl

NMR-spectroscopy has matured to be routinely applied at 1.5 Tesla c]inical MR-scanners. During the past two years experience using localized 31P and water suppressed |oca]ized IH spectroscopy has accumu]ated at out department and in order to evaluate c| inla| indications for NMR-spectroscopy in CNS disease, 136 examinations had been reviewed. There were three groups, intracranial tumors (n : 65)° ischemia (n : 36) and a third group of 35 patients composed of inf]ammatory or metabo|ic white marter disease. A|] examlnations had been performed at a 1.5 Tes|a imaging spectroscopy system (Magnetom, Siemens, FRG). Individual examinations lasted between 40 and g5 minutes, a standard imaging head coil was used for proton spectroscopy and a double tuned He|mholtz-coi| for 31P spectroscopy. Localization depended on the STEAM-sequence for IH and ISIS for 31P. The re|at ive|y low sensit ivi ty (IH : i to 27 ml; 31P : 64 to 125 m|) is an obvious restrict ion for the method in primary diagnosis. In metaboIic disorders or extraaxial tumors spectroscopy improves the specifity of NMR-imaging. The application of IH-, 31P-NMR-spectroscopy at presence is directed to monitor neoplastic and ischemic disease and to eventually document therapeutic effects. Another group of patients who may directly benefit from spectroscopy are in-born errors of metabolism and secondary disorders of the oxidative phosphorylation in early childhood. In conclusion NMR-spectroscopy at present is predominant|y directed to clinical research, but there exist some indications to perform localized CNS spectroscopy offering impact to the patient management.

Dept. of Magnetic Resonance, University of Innsbruck, Anichstraße 35, 6020 Innsbruck, Austria

504

IMPACT OF MR-IMAGING IN THE ASSESSMENT OF "INNER CEREBRAL TRAUMA"

G. Birbamer (1, 2), A. Kampf! ( I ) , S. Felber (1, 2), F. Aichner ( i , 2), F. Gerstenbrand (2)

In c]osed head trauma the neuropatholog ica l pat tern of axonal i n j u r i e s w i th in the bra in stem, corpus callosum and deep whi te marter ( " inner cerebral trauma") is incomplete ly de l ineated by CT due to r e l a t i v e i n s e n s i t i v i t y towards small non hemorrhagic les ions. In order to eva luate the impact of MRI in the assessment of inner cerebral trauma 76 pa t ien ts wi th severe head i n j u r y were inves t iga ted between 1989 and 1990. A l l examinat ions were performed on a 1.5 Tesla Magnetom using Tl (550/15/TR/TE) and T2 (2400/15/90) as wel l as 3D grad ient echo sequences (40/5/a lpha = 40 degrees). A l l pa t ien ts had been monitored by continuous pulse ox imetry , capnography, ECG and blood pressure manometry. 45 examinations were performed in general anesthesia. MR-imaging detected more lesions than CT in a l l pa t ien ts and came close to neuropatholog ica l d i s t r i b u t i o n . 3D grad ient echo sequences al lowed a be t t e r de tec t ion of even small lesions w i th in the corpus callosum and the bra in stem due to reduced p a r t i a l volume averaging. The pat tern of the lesions was evaluated wi th especial respect to the d i r e c t i o n of the t raumat is ing forces. MR-imaging al lowed a be t t e t d i f f e r e n t i a t i o n between primary and secondary post t raumat ic les ions. Whereas CT remains s u f f i c i e n t in the i n i t i a l surg ica l management, MRI w i l l be the modal i ty of choice fo r prognost ic cons idera t ion and conservat ive management, as wel l as fo r f u r t he r understanding of pathomechanism of cerebral trauma.

Dept. of Magnetic Resonance (1) and Oept. of Neurology (2), Unlversity of /nnsbruck, Anichstraße 35, 6020 Innsbruck, Austria

M U L T I P L E S C L E R O S I S : C O R R E L A T I O N O F N E U R O P A T H O L O G I C A L F I N D I N G S W I T H P R E -

A N D P O S T M O R T E M M R I

M.Brainin (1), H.Lassmann (2), and A. Neuhold (3)

Since formalin-fixed brains of multiple sclerosis (MS) patients have been demonstrated to show similar lesions as seen in vivo for other patients (Stewart WA et al.:Lancet 1984: 412; Nagara et al: J. Neurol Sci 1987: 67), few further comparisons of neuropathological data and postmortem MRI-scans have been made. To our knowledge, this is the first report comparing pre-and postmortem MR-scans with neuropathological findings in a case of clinically definite MS. A 55 year-old female patient had a four year history of chronic progressive paraparesis preceded by several episodes of optic neuritis. She was hospitalized because of a hip fracture and her neurological state had been stable. The CSF analysis had shown an increased intrathecal IgG production and oligoclonal bands. Visual evoked potentials showed a prolonged P100 on both sides. An MRI scan had confirmed the diagnosis six weeks before her death due to pulmonary embolism. The brain was fixed in a 10% formalin solution and post- mortem scans were made with transversal SE sequences according to the premortem cüts (0.5 Tesla). The dissection of the brain was performed in corresponding planes and selected areas of interest were taken for histological stainings. Extensive periventricular demyelination, shadow plaques and one plaque in the brain stem are compared with the in-vivo and postmortem scans.

(1) Neurologische Abteilung, NO Landesnervenklinik Gugging, A-3400 Maria Gugging (2) Neurologisches Institut der Universität Wien und (3) Institut für Bildgebende Diagnostik, Krankenanstalt Rudolfinerhaus Wien

THE H I S T O L O G I C C O R R E L A T E OF W H t T E M A T T E R AND PERIVENTRICULAR MRI SIGNAL HYPERINTENSITIES F. Fazekas, R. Kleinert, H. Offenbacher , F. Payer, G. Kleincrt, R. Schmidt and H. Lechner

Mixed and T2-we igh t ed magne t i c r e sonance i m a g i n g (MRI) s e q u e n c e s f r e q u e n t l y d i s p l a y u n e x p e c t e d a r e a s o f pe r iven t r i cu la r (PVH) as weil as deep and subcor t ica l whi te mat ter hyper in tens i ty (WMH). The pat tern and extent of such changes may be quite var iable and thei r cause and cl inical s i gn i f i c ance are still c o n t r o v e r s i a l . . W e the re fo re c o m p a r e d the imag ing rcsults and pa thologic f indings on the bra ins of 10 e lder ly pat ients who had unde rgone MR1 shor t ly before d e a t h . In genera l there was no corrc la te to the hyper in tense caps a round the ven t r i cu l a r horns and punc ta t c W M H by only visual inspect ion of 5 mm thick brain slices obta ined parallel to the MRI plane. His to logy revealed areas of edema a round la rge whi te ma t t e r veins , a r a r e f i ca t i on of f ibers and a v a r y i n g d e g r e e o f d e m y e l i n a t i o n in the fo rmer . The ex tens ion o f such changes a longs ide the la tera l ven t r i c l c s was reflected on MRI by a band of PVH. Punctate WMH, when iden t i f i ed , cons i s t ed mos t l y o f subt le p e r i v a s c u l a r t i s sue changes with a va ry ing degree of edema, demye l ina t ion and g l i o s i s a r o u n d both smal l a r t e r i e s and ve ins . L a r g e r hyper in tens i t i e s tended to conta in small centra l lacunes and t h e r e was e v i d e n c e for m a r k e d sma l l v e s s e l d i s e a s e c h a r a c t e r i z e d by mul t ip le in farc t s and s p o n g i f o r m c h a n g e s o f the whi te m a t t e r in cases wi th i r r e g u l a r PVH and conf lucn t WMH. Our f i n d i n g s p rov ide f u r t h e r e v i d e n c e for the v a s c u l a r o r i g i n o f W M H but s u g g e s t a d i f f e r e n t e t i o l o g y fo r pe r iven t r i cu l a r h igh s ignal in tensi ty caps and bands .

N e u r o l o g i s c h e Kl inik and P a t h o l o g i s c h e s Ins t i tu t der Kar l - Franzens Univers i tä t Graz, Auenbruggerp la t z , A-8036 Graz

PREVALENCE AND F O L L O W UP OF WHITE MATTER AND P E R I V E N T R I C U L A R M R I H Y P E R I N T E N S I T I E S IN ASYMPTOMATIC VOLUNTEERS H. Of fenbacher , F. Fazekas , R. Schmidt , K. Niederkorn , S. Horner, F. Payer and H. Lechner

Unexpec ted lesions in the brain p a r c n c h y m a , pa r t i cu la r ly in the whi te ma t t e r are of ten seen on m a g n e t i c r e s o n a n c e i m a g i n g (MRI) o f pa t i en t s s tud ied for v a r i o u s c t i n i ca l r easons . In o r d e r to p rov ide fu r the r i n f o r m a t i o n on the p r eva l ence and extent o f these whi te ma t t e r ( W M H ) and p e r i v e n t r i c u l a r h y p e r i n t e n s i t i e s ( P V H ) in the " n o r m a l " p o p u l a t i o n , we p r o s p e c t i v e l y s tud ied 101 a s y m p t o m a t i c volunteers ranging in age from 31-84 years (mean 55 years). Fol low up studies were obtained in 29 individuals af ter a mean of 15 months. W M H were present in 48% of the study subjects and most of them were iden t i f i ed as p u n c t a t e foci . The i r p r e v a l e n c e showed a s t rong age related increase from 11% in the fourth d e c a d e to 71% in those ind iv idua l s 70 yea r s or o lder . Moreover , WMH were detected s igni f icant ly more often at the presence of ce reb rovascu la r risk factors (p<0.05). PVH were observed in 45% and consis ted p redominan t ly of caps and/or lines. Their preva lence also increased with age but was not related to the presence o f risk factors. More prominent W M H and PVH were seen in 6% and 4% of subjects , respect ively, and were a s soc i a t ed with h i g h e r age and c e r e b r o v a s c u l a r risk factors . Fol low up studies did not reveal an increase o f size in any o f the les ions and only small f luc tua t ions in respect to the lesion number . Our study indicates a high prevalence of WMH and PVH even in c l in ica l ly a s y m p t o m a t i c ind iv iduals .

N e u r o l o g i s c h e Kl in ik der K a r l - F r a n z e n s U n i v e r s i t ä t Graz , Auenbruggerp la t z 22, A-8036 Graz

DIAGNOSTIC IMPACT OF GD-DTPA IN MR-IMAGING OF INTRA- AND PARASELLAR TUMORS

A. Kampfl ( I ) , G. Birbamer ( I , 2) , S. Felber ( I , 2), F. Aichner ( i , 2), F. Gerstenbrand (2)

MR-imaging has a l ready proved to be useful in eva lua t ion of pa t ien ts suspected processes in the se l l a t u rc i ca . To assess the ro le of Gd-DTPA enhanced MR-imaging 40 pa t ien ts harbouring of i n t r a - or pa rase l l a r space occupying lesions were studied r e t r o s p e c t i v e l y . A l l MRl-studies were performed on a 1.5 Tesla Magnetom using a c i r c u l a r po la r i zed head-coi l (FOV = 25 cm). The imaging pro toco l consisted of Tl and PD, T2 weighted images. Add i t i ona l Tl weighted scans were obtained immediately a f t e r i n j e c t i o n of Gd-DTPA (0 . i mmol/kg). In 6 pa t ien ts a 3D FLASH sequence was performed which f u r t h e r improved the anatomical r eso l u t i on . 25 pa t ien ts had p i t u i t a r y adenomas, i0 pa t ien ts had pa rase l l a r meningeoma. In one pa t i en t a teratoma of the t h i r d v e n t r i c l e and in orte case a craniopharyngeoma and a ganglioneurinoma was diagnosed. Two pa t ien ts had pa rase l l a r granulomatous inf lammatory processes. Gd-DTPA improved the d i f f e r e n t i a l diagnosis in 20 of 40 pa t i en ts . 3 pa t ien ts w i th a p i t u i t a r y microadenoma and 2 pa t ien ts w i th a pa rase l l a r meningeoma were i d e n t i f i e d on ly by the use of Gd-DTPA. In conclusion the use of Gd-DTPA in diagnosis of s e l l a r and pa rase l l a r processes f u r t h e r improved the wel l-known advantages of MR-imaging.

Dept. of Magnetic Resonance ( i ) and Dept. of Neurology (2) , Un i ve rs i t y of Innsbruck, Anichstraße 35, 6020 Innsbruck, Aus t r ia

DIAGNOSIS OF CERVICAL DISK DISEASE MRI VERSUS CEBVlCAL MYELOGRAPHY G.Perneczky* ,F.W.Böck* ,A.Neuhold** and M.St i ska l * *

505

In a prospectlve study of 63 surglcal patzents nuclear magnetlc resonance imaging (MRI) was compared with myele- graphy to establlsh whether lnvasive diagnostic studles of cervlcal compresslon syndromes can be omztted. Surgery was done along the anterior route throughout. 45 patlents had herniated disks wlthout bony compression. In 10 patients bony compresszon of the dural sac or nerve root without disk hernation was found to be present. 5 patlents presented wlth both hernlated disks and severe osteophytic narrowÂng of the spznal canal or the inter- vertebral foramen. While MRI in the T 1-weighted and gradient echo modes matched the diagnostic accuracy of lnvaslve myelography (95%), T 1 and T 2-weighted MRI images a•one were assoclated with an error rate of 10 %. In patlents with medlal protruslon myelography did not always show the true extent of compresslon, whereas MRI tended to miss small laterally protruding dlsk fragments. Cervical myelography contlnues to have a place in the diegnosis of cervical disk dzsease, whenever cllnzcal signs and symptoms do not agree with MRI data.

*Krankenanstal t Rudol fs tz f tung Wien, Neurochirurg.Abt . Juchgasse 25, A 1030 Wien ** Pr ivatkrankenhaus Rudolf inerhaus, B i l l r o t h s t r . 78 A 1190 Wien

Progressive multlfocal I,eucoencephalopathy (PML) in a patient with non Hodgkin s lymphoma.

Hitzenberger P (1), Alesch F (5), Kttmpan W (3), Lindner K (1), Neuhold A (2), Selmaidbauer M ( 4 ) , Grisold W (1)

Progressive multifocal leucoencephalopathy (PML) is a clinically progressive asymmetric disorder of the central nervous system. It is usually associated with disorders of immunedeficiency. A number of studies have identified JC papovavirus in brain tissue as the causative agent. We report a 49 year old white male patient suf- fering from nen Hodgkin's lymphoma (immunocyto- ma) of the skin. He received immunosuppressive treatment for several years. A CCT scan was performed due to the occurrence of acute hemianopia and aphasia. A hypodense lesion was located in the left occipital lobe and a cerebrovascular cause was suggested. Clinically the patient deteriorated. The CCT lesion remained constant and MRI showed multi- ple white marter lesions in both hemispheres. Brain biopsy was performed and PML was con- firmed histologically.

(1) Neurologische Abteilung und Ludwlg Boltzmann Institut für klinische Neurobiologie, Kaiser Franz Josef Spital, 1100 Wien, Kundratstr.3

(2) Röntgeninstitut der Krankenanstalt Rudolfmerhans (3) Röntgeninstitut des Kaiser Franz Josefs Spitales (4) Neurologisches Institut der Universität Wien (5) NeuroehirurgJsche Universitätskll-;k» Wien

PreoDerative HR Tomo~raDhv in Con~enital Scoliosis W. Judmaier, M. Lener, K. Wicke, H. Wendtner

C o n v e n t i o n a l r a d i o l o g i c a l m e t h o d s a r e w i d e l y u s e d f o r t h e p l a n n i n g o f o r t h o p e d i c s u r g i c a l i n t e r v e n t i o n s i n c o n g e n i t a l k y p h o s c o l i o s i s . P l a i n f i l m s o f t h e v e r t e b r a l c o l u m n , i n c l u - d i n g b e n d i n g f i lms , t o m o g r a p h y a n d c o m p u t e d t o m o g r a p h y a r e i d e a l l y s u i t e d to a s s e s s t h e d e g r e e o f s c o l i o s i s a n d to d e p i c t v e r t e b r a l m a l f o r m a t i o n s . S i n c e b o n y d e f o r m i t i e s o f t h e s p i n e a r e f r e q u e n t l y c o m b i n e d w i t h m a l f o r m a t i o n s o f n e u r a l s t r u c t u r e s , i t i s i m p o r t a n t t o d i a g n o s e m a l f o r m a t i o n s o f t h e s p i n a l c o r d p r i o r to s u r g e r y , w h i e h c a n n o t b e d o n e a d e q u a t e l y u s i n g X - R a y p r o c e d u r e s . T h e r e f o r e we i n c l u d e d MR t o m o g r a p h y (MRT) in t h e s t a n - d a r d w o r k u p p r o t o c o l o f s c o l i o t i e p a t i e n t s . I n 20 p a t i e n t s we c o u l d f i n d 7 a b n o r m a l i t i e s o f t h e m y e l o n i n c l u d i n g t w o m y e l o m e n i n g o c e l e s , t w o t e t h e r e d c o r d , t w o d i a s t e m a t o - r e s p . d i p l o m y e l i a a n d o n e s y r i n g o m y e l i a . T h e s u p e r b s o f t t i s s u e c o n t r a s t o f MRT a l l o w s d i r e c t i m a g i n g o f t h e s p i n a l c o r d s t r u c t u r e s w i t h o u t t h e u s e o f c o n t r a s t a g e n t s a n d i s e s p e c i a l l y h e l p f u l i n r u l i n g o u t i n - t r a s p i n a l l i p o m a s , d e r m o i d o r e p i d e r m o i d t u m o r s . T h e m u l - t i p l a n a r s c a n n i n g c a p a b i l i t y o f MR a l l o w s t o a c h i e v e o r - t h o g o n a l s l i c e s in r e s p e c t t o t h e s e v e r e l y d i s t o r t e d a n a t o m y . By a p p l y i n g t h r e e d i m e n s i o n a l v o l u m e t r i c a c q u i s i - t i o n t e c h n i q u e s i t i s a l s o p o s s i b l e t o r e c o n s t r u c t i m a g e s in a c u r v e d p l a n e , t h u s p r o j e c t i n g t h e s p i n a l s t r u c t u r e s in a s i n g l e p l a n e a n d s i m u l a t i n g t h e p o s t o p e r a t i v e s t a t u s . T h e l a c k o f i o n i z i n g r a d i a t i o n i s a n o t h e r i m p o r t a n t a d v a n t a g e in t h e s e y o u n g p a t i e n t s , s i n c e r e p e a t e d e x a m s p r e - a n d p o s t o p e r a t i v e l y u s i n g X - R a y t e c h n i q u e s a r e i n e v i t a b l e . T h e r e l a t i v e l y l o n g d u r a t i o n o f t h e MRT e x a m i n a t i o n i s i t ' s m a j o r d r a w b a c k . U n c o o p e r a t i v e p a t i e n t s h a v e t o b e e x a m - i n e d u n d e r s e d a t i o n o r u s i n g g e n e r a l a n e s t h e s i e u I t i s e s s e n t i a l t o p o s i t i o n t h e p a t i e n t a s c o m f o r t a b l y a s p o s s i b l e in t h e m a g n e t to a v o i d m o t i o n a r t e f a c t s . H o w e v e r , i n n o n e o f o u t p a t i e n t s d i d t h e m a l f o r m a t i o n o f t h e s p i n e p r o v e to b e i n c o m p a t i b l e w i t h a s u c c e s s f u l exam.

MR I n s t i t u t , K l in ik I n n s b r u c k , A n i c h s t r 0 3 5 , 6020 I n n s b r u c k

506

DIAGNOSIS OF CEREBRAL MALFORMATIONS BY MRI AND REAL TIME SONOGRAPHY

D.Wimberger * , G.Zoder + , G.Bernert + , H.Imhof x

• Neurological Department of the University of Vienna , + Kinderklinik Wien-Glanzing , x Department of Radiology and MR Institute , University of Vienna

The alm of out study was to examine dlagnostlc facilltles of MRI compared with Real Time Scan findings , concerning cerebral malformations in infancy.

We examlned 33 infants and young children , aged from 1 day to 4 years , mean age 6,3 month , in whom a cerebral mal- formation had been diagnosed or assumed by RT sonography. MRI was done using a 1,5T superconducting system. T1 ( TR 700/TE 15msec ) and T2 ( TR 2500/15,70msec ) images were performed in 3 sectlon planes. For RT sonography we used a mechanical sector scanner working at 5 er 7,5 MHZ. Maximal distance between MRI and RT scan was 5 days before closure of the fontanel and up to 3 years in elder children. RT scan diagnoses were : DandyWalker Complex {n=11) , partial or complete agenesis of corpus eallosum (n=5) , holopros- encephaly (n=2} , septal agenesis (n=10) , combined mal- formatlons (n=10) , not classifiable(n=2). In classifiable cases RT- and MRI diagnoses correlated roughly. In 2 cases which could not be classified by RT sonography because of large hemorrhages , MRI revealed a Dandy Walker Syndrome and a tuberous sclerosis. Complementary MRI informations concerning disturbances of myelinisatlon , grey/white marter differentiation and assoclated malformations could be won in 17 cases. In one patient RT sonography pro- vided with information superior to MRI. A septatlon within a cyst was found.

MRI was superior to RT sonography in 51,5% of the patients RT scan was superior to MRI in 1 patient. In 27,2% (9 par.) MRI findings altered therapeutical management or prognostic predictions. Thus MRI seems to be a useful dia- gnostic tool in infants and young children with cerebral malformations. RT Sonography will remain the Imaging method of cholce for screenlng purposes.

CYSTS OF SEPTUM PELLUCIDUM ASAPOSSIBLE SOURCE OF EMOTIONAL ABNORMALITIES AND HEADACHE WITHOUT SIGNS OF HYDROCEPHALUS IN CT Ch. De r f l e r , F. GrJeßmayer and B. Keppl inqer

Cavum septi pellucidi or Cavum vergae in the adult, es resldu~s of physiologically existing cavities in the 4ntrauterine developing brain, may cause intermittent or permanent hydrocephalus with signs of raised intra- cranial pressure if expanding, or if forming a cyst. Various ogerative techniques have been described in treating these cysts - the latest being stereotactic aspiration.

Reviewing the literature we found hints on a possible association of septum pe]lucidum cavities wJth behavioural disturbances and eren schizophrenia - ]ike osychoses in patients, which did not necessarily shotv signs of hydrecephalus in CT.

Based on 3 own cases of cysts of septum pel].ucidum in CT in patients which complaJned of intermittent attacks of heedaches with nausea and vomiting and exhibited also emotional and mental disturbances, we again discuss the 9essibility of intermittent raising of intracranial pressure and a possible essociatiün with psychic dysfunctions - an assurnption which is supported by the clese relation of such cavities to limbic structures.

Landesnervenklinik West, Neurologische Abteilung, A-3362 Mauer

COLOR-CODED DUPLEX SONOGRAPHY OF HIGH-GRADE CAROTID ARTERY STENO51$

K. Nieder kor n ,S. Hor ner ,M.D uft

Color flow imaging is a new way to visua;ize blood flow by meens of multigate pulsed Doppler simultane¢usly with the B-mode image of the vessel .This technique h«s the advantage, that complex circulatory situations, which occur frequently in the carotid bifurcation like turbulent flow and f]ow in stenosed areas cao be detected and visualized and ma'/ also be easily docu mented. The aim of the present study is to show the possible value of color-coded Duplex sonography as an additional source of information in the diffucult field of sonographic differentiation of subtotal stenosis and occlusion of the cervical internal carotid artery(ICA). Duplex scanning and color flow imaging of the carotid arteries was performed in 21 patients ( T3 men,8 women, mean age 69 years) with together 25 high-grade ICA stenoses (ultrasound system:Yingmed CFM 700,Horten,Norway; B.mode frequency 7.5 MHz, Color Doppler frequency 6 MHz). tn 4 cases (16%) color flow imaqirq added siqni f icant

information to the Duplex result. Two of these patients had confirming angiography.5 stenoses ware so-called "low-flow" stenoses, with normal or reduced f]ow velocities due to the severity of the lesion. In these cases color Doppler was essentia] in locating the Doppler signal within the highly obstructed ICA and confirming the diagnosis of stenosis. In all cases a quick Iocation of the patent channel within the stenosing plaque was possible with the help of color flow imaging, enabling the sonographer to obtain the stenotic Doppler signal precisely and quickly. These results indicate that coior flow imaging is a cl inically valuable diagnostic tool, increasing the accuracy of Dup]ex scanning in the diagnosis of subtotal ICA stenosis.

Department of Neurology, Kar] Franzens Un iververs i t y , Auenbruggerp]atz 22, A-8036 Graz

CT-LESION DOES NOT PREDICT ETIOLOGY OF N O N - LACUNAR I S C H E M I C STROKE

S.Lang, W.Haitzinger, and M.Brainin

Patients with completed stroke are prospectively registered in the Klosterneuburger Schlaganfall-Datenbank, a single-center stroke registry established in 1988. All 500 patients, who entered this registry within the first two years, are routinely investigated by means of CT, duplexsonography, routine cardiac and laboratory examinations. Arteriography, transoesopagheal echocardiography and MRI are performed in selected cases. All patients are classified into defined etiological categories. The CT-findings are evaluated by means of a simple pretested documentation with a high interrater reliability. For the purpose of this study the CT-scans of 278 patients with ischemic non-lacunar stroke were analysed, comprising the following etiologies: unknown, atherothrombosis of the large craniocervical vesseis, and cardiac embolic stroke. Cardiac embolic strokes are shown to be more frequently associated with pure cortical infarctions as weil as with infarctions in the territory of the PCA, though not on a significant level. Neither enhancement status nor hemorraghic infarction was significantly correlated with one stroke subtype. It is concluded that the CT-findings alone do not permit any conctusions about the etiology of ischemic stroke.

Institut zur Erforschung und Verhütung des Schlaganfalls der NÖ wiss.Landeskademie und Neurologische Abteilung der NÖ Landesnerven-klinik Gugging, A-3400 Maria Gugging