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Physiological activation measured by Tc-99m HMPAO brain spect compared with quantitative Xe-133 rCBF
P7
P8 PATFERNS OF NORMAL MENINGEAL ENHANCEMENT ON 1.5 T MR IMAGING
~ , O. P. Eldevlk, M.D., L K. Cohen, M.D., University of Michigan Medical Center, Ann Arbor, MI Pu _rpose: To evaluate the normal patteros of intraeranial meningeal and ependymal enhancement contrast-enhanced head MR scans. Methoct¢.. The intraeranial meninges and ventrieular ependyma were evaluated prospectivaly on 177 eonsocutive pre-conWast and post-contrast coronal Tl-weighted 1.5-T MR scans. Enhancement was graded on a 6 point scale (range: no enhanceraont to diffuse, irregular enhancement) and correlated with clinical history in each ease. Results: 115 scans showed a "normal" paUem of meningeal enhancement (either no enhencemen or only focal enhancement of a region on < 3 contiguous sections or < 2 ara on a single section). Of these patients. 80 had otherwise normal scans, 15 demonstrated minimal inwscranial abnormalities (areas of isehemic change, etc.) and 20 showed significant abnormalities (predominantly intra-aslal tumors).
REPRESENTATION OF WHITE MA'ITER TRACTS ON MRI (FRONTAL, SAGITTAL AND HORIZONTAL PROJECTIONS), Mark Glazer, M.D., Ruth G. Ramsey, M.D., Keiichiro Kasai, M.D., Haruo Isoda. M.D., Ph.D., Noriko Murayama, M.D., Ph.D., George,s Salamon, M.D., The University of Chicago, Cldcago, IL Purpose: A 3D method of analysis of white matter has been proposed to follow dieir main tracts in normal or pathological subjects. Methods: Correlations have been made between an in vivo MR study and postmortem analysis of the brain with myelin stain. The in vivo MR examinations were made on a 1.5 T MR unit with I mm sections using spoiled gradient echo volume and spin echo imaging. A special program (vox tool) allowed us to follow any tract on three orthogonal planes. Results: The following pathways have been analyzed: Pyramidal and sensitive fibers to areas 1,2,3, visual pathways, cal]osal fibars, superior and inferior longitudinal bundles, and thalamocortlcal tracts. Conelnsions: Determination of some main white matter tracts may be of extreme importance in MRI analysis of disconnection syndromes such as conduction aphasia, in the surgery of epilepsy, in vascular diseases such as for differentiation between necrotic areas and damyellnallng areas. It is also useful for interpretation and understanding of PET end functional MRI (fMR1) studies with ' neuropsychologic tests.
62 sc .uns demonstra .t.ed.abnormal muaiageal enhenuament. Of thase, 55 demonstratad sigulfieent assocmted abnormaliues (tumors, shunts, post-operative) and 7 did not show any other iatrecrani abnormalities. C t ~ l .usln.~: An abnorm.al,pattern of meningeal enhancement correlates highly ( p < .001) with slgnificent abnormalines on head MR scans. Therefore, significant intracranial meningeal/epeodymal enhancement should prompt a search for an etiulogy/explenatiort (either on the .c3tyrent . man or in the patient's past medical history) as such enhancement should not be eoosldered a normal fmdthg.
P9 P H Y S I O L O G I C A L A C T I V A T I O N M E A S U R E D B Y Tc-99m H M P A O B R A ~ SPECT C O M P A R E D W I T H Q U A N T I T A T I V E Xe-133 tCBF. Geor~ Deutseh. Ph.D.. J.M. Mountz, M.D., Ph.D., H.G. Liu, M.S. University of Alabama at Birmingham Medical Center, Birmingham, A L ~ : The nonlinearity of Tc-99m I-IMPAO dis~ibufion at higher regional cerebral blood flow (rCBF) may affect its application to rCBF activation studies. We compared cortical rCBF changes observed on Te-99m I-IMPAO S P E C T scuns with quantitative rCBF obtained using Xe-133 eleurance in 20 cerebrovascular disease patients who had vaseulur reserve testing using both Diamox (acetuzolamide) and CO2 vasodllatory stress tests. Methods: 740 MBq Te-99m H M P A O was injected 15 minutes after lg Diamox injection. SPECT scanning was then performed on an A D A C Gennsys camera. Quantitative rCBF studies were performed on a Novo 32e cerebrograph using 1 minute inhalation of Xe- 133 (10mCi/liter air) during 5% CO 2 stress testing. All subjects also had S P E C T and Xe rCBF studies during a "resting" state. SPECT data was analyzed using an automated cortical R O I generator and compared to Xe rCBF values calculated over the same regions. Results: Diamox S P E C T revealed asymmetries and focai defects during stress consistent with CO s Xe rCBF studies, but Xe rCBF was more sensitive to baseline asymmetries and minimal flow changes due to its absolute quantification. Conelualons: I-IMPAO S P E C T allows accurate assessment of the brain topography involved in vasodilatory stress testing. Quantffieation provides additional information, however, and should be pursued with Xe S P E C T methods.
Pll EVALUATION OF OCULAR M~LANOMA: MRI OR ULTRASOUND? Kundan L. Gupt,% I~, D, Daisy Gupta, Bradey S. Shore, M.D Tulane University Medical Center, New Orleans, Louisiana Purpose: Delineating the optimal MR imaging sequences and usefulness of ultrasound in evaluating ocular melanoma. ~Materials and Methods: lntraocular melanoma is the most common intraocular malignancy in adults accounting for 80% of primary ocular malignancies. Magnetic resonance imaging was compared to ultrasound in the efficacy of evaluating, detecting characterizing 183 ocular m e l a n o m a cases. The findings, size of tumor, presence of r e t i n a l d e t a c h m e n t a n d hemorrhage are analyzed. Results: Heavily T-1 weighted sequences were considered more sensitive than either T-2 or proton density images in revealing information regarding deeper lesions and providing superior contrast resolution and tissues characteristics. Ultrasound, however, is invaluable in that it is cost effective, easily provided on an o u t p a t i e n t basis and provides higher resolution in detecting smaller lesions. Conc~lusiQn: MRI and US are both excellent imaging modalities in the medical care and foliow-up of the pre and post surgical ocular melanoma. Knowledge of each modalities effiG'tiy,and limitations facilitates optimal cost effective patient care.
PlO MRI OF TEMPORALLOBE EPILEPSy: COMPARISON OF S E Q ~ C E S . Authors:
LeoJ. Wolanqkv. M.D.. T. Kate, B.S., J. A. Mal~ian, M.D., B. K. Praman~ MD, D. Marks, M.D., J. Pak, M.D., H-J.Lee, M.D. UMDNJ, Newark, New Jei~ey
Ptwtmse: Because of growing In,crest in seizure surgery for intractable temporal Inl~ epilepsy, arcurato IVJ~Idingnesisof hippocampal scleresis Is esserdlal. Various studt5 have showed differences in r~ults, which have depeaded, in part, on techniques employed. The purpose of this study was to cmnpare the effectiveness of four differeat MRI sequences. The folinwingfour MRI sequences were compared: Thin-section3D Fomier Tramfform Spoiled Grant, t-Echo (SPGR) Tl-weighted images; High-resolution fast s0n-echa T2weighted images; Ceaventional sp'm-echo Balanced imas~; and Narrow-bandwidth (4 kHz) ¢onvmtio~l spin-echo T2-weigMedInmgrs. Each sequence was read separately by a reader banded to the ~a~msiz. R~ult~:
The most effective sequemo~ were T2-FSE (sensltivit y : 100%; spt¢lfldty : 80%)
and SPGR (mmedtivity: 86.7%; and spedlkity : $4.6%). Narrow handwldth 1"2tended to be lem effective (Semitivtty : 78.6%; specificity : 71.4%). Bahmced hnages had poor Semlelvltybee.ainuof poor distlm~n Ofklppocampus from vemrlde. Tl-weightod SPGR and T 2 - w ~ FSE tend to be the most effective seque~es for tha dlal~eets OfIdppeompal atrophy and appear to be ¢omplemeatary.
P12 T c - 9 9 m H M P A O BRAIN S P E C T IN C H I L D H O O D NARCOLEPSY: E V A L U A T I O N OF ITEM, Non-REM, AND T H E AWAKE STATE. Elmer C. San Pedro. M.D,, LM. Mountz, M.D., Ph.D., M. Wise, M.D., H.G. Lin, M.S. University of Alabarna at Birmingham, Birmingham, AL.
Put'nose: The inability of accurately identifying the exact moment of tracer injection in relation to the sleep-wake state contributes to conflicting reports in the medical literature regarding rCBF changes in narcolepsy. We ased videe/EEG/polygraphic monituring to dccurocnt sleep states prior to tracer injeedon. Methods: Brain SPECT imaging was performed after three separate injections of Te-99m HMPAO (over a 3-5 day period) to evaluate brain activity during wakefulness, REM and Non-REM sleep in two children with narcolepsy. Results: Semi-quantitative analysis showed significant increases in global rCBF during NOn-REM (20%) and during REM (9%) sleep as compared to the awake state in the first subject. There was also significant hemispheric perf~sicu asymmetry during Non-REM, R>L (8.5%) and during REM L>R (5%) as compared to wakefulness. The second subject developed minor bemispheric perfusion asymmetries during REM and NOn-REM when compared to wakefulness. Conclusions: Although there were only two subjects in this study, our results demonstrate that semiquamitative brain SPECT coupled with video/EEG/polygraphic monituring is able to detect rCBF changes in each stage of the sleep-wake cycle and may be helpful in future studies of rCBF changes in narcolepsy and other sleep disorders.
P8 PATFERNS OF NORMAL MENINGEAL ENHANCEMENT ON 1.5 T MR IMAGING
~ , O. P. Eldevlk, M.D., L K. Cohen, M.D., University of Michigan Medical Center, Ann Arbor, MI Pu _rpose: To evaluate the normal patteros of intraeranial meningeal and ependymal enhancement contrast-enhanced head MR scans. Methoct¢.. The intraeranial meninges and ventrieular ependyma were evaluated prospectivaly on 177 eonsocutive pre-conWast and post-contrast coronal Tl-weighted 1.5-T MR scans. Enhancement was graded on a 6 point scale (range: no enhanceraont to diffuse, irregular enhancement) and correlated with clinical history in each ease. Results: 115 scans showed a "normal" paUem of meningeal enhancement (either no enhencemen or only focal enhancement of a region on < 3 contiguous sections or < 2 ara on a single section). Of these patients. 80 had otherwise normal scans, 15 demonstrated minimal inwscranial abnormalities (areas of isehemic change, etc.) and 20 showed significant abnormalities (predominantly intra-aslal tumors).
REPRESENTATION OF WHITE MA'ITER TRACTS ON MRI (FRONTAL, SAGITTAL AND HORIZONTAL PROJECTIONS), Mark Glazer, M.D., Ruth G. Ramsey, M.D., Keiichiro Kasai, M.D., Haruo Isoda. M.D., Ph.D., Noriko Murayama, M.D., Ph.D., George,s Salamon, M.D., The University of Chicago, Cldcago, IL Purpose: A 3D method of analysis of white matter has been proposed to follow dieir main tracts in normal or pathological subjects. Methods: Correlations have been made between an in vivo MR study and postmortem analysis of the brain with myelin stain. The in vivo MR examinations were made on a 1.5 T MR unit with I mm sections using spoiled gradient echo volume and spin echo imaging. A special program (vox tool) allowed us to follow any tract on three orthogonal planes. Results: The following pathways have been analyzed: Pyramidal and sensitive fibers to areas 1,2,3, visual pathways, cal]osal fibars, superior and inferior longitudinal bundles, and thalamocortlcal tracts. Conelnsions: Determination of some main white matter tracts may be of extreme importance in MRI analysis of disconnection syndromes such as conduction aphasia, in the surgery of epilepsy, in vascular diseases such as for differentiation between necrotic areas and damyellnallng areas. It is also useful for interpretation and understanding of PET end functional MRI (fMR1) studies with ' neuropsychologic tests.
62 sc .uns demonstra .t.ed.abnormal muaiageal enhenuament. Of thase, 55 demonstratad sigulfieent assocmted abnormaliues (tumors, shunts, post-operative) and 7 did not show any other iatrecrani abnormalities. C t ~ l .usln.~: An abnorm.al,pattern of meningeal enhancement correlates highly ( p < .001) with slgnificent abnormalines on head MR scans. Therefore, significant intracranial meningeal/epeodymal enhancement should prompt a search for an etiulogy/explenatiort (either on the .c3tyrent . man or in the patient's past medical history) as such enhancement should not be eoosldered a normal fmdthg.
P9 P H Y S I O L O G I C A L A C T I V A T I O N M E A S U R E D B Y Tc-99m H M P A O B R A ~ SPECT C O M P A R E D W I T H Q U A N T I T A T I V E Xe-133 tCBF. Geor~ Deutseh. Ph.D.. J.M. Mountz, M.D., Ph.D., H.G. Liu, M.S. University of Alabama at Birmingham Medical Center, Birmingham, A L ~ : The nonlinearity of Tc-99m I-IMPAO dis~ibufion at higher regional cerebral blood flow (rCBF) may affect its application to rCBF activation studies. We compared cortical rCBF changes observed on Te-99m I-IMPAO S P E C T scuns with quantitative rCBF obtained using Xe-133 eleurance in 20 cerebrovascular disease patients who had vaseulur reserve testing using both Diamox (acetuzolamide) and CO2 vasodllatory stress tests. Methods: 740 MBq Te-99m H M P A O was injected 15 minutes after lg Diamox injection. SPECT scanning was then performed on an A D A C Gennsys camera. Quantitative rCBF studies were performed on a Novo 32e cerebrograph using 1 minute inhalation of Xe- 133 (10mCi/liter air) during 5% CO 2 stress testing. All subjects also had S P E C T and Xe rCBF studies during a "resting" state. SPECT data was analyzed using an automated cortical R O I generator and compared to Xe rCBF values calculated over the same regions. Results: Diamox S P E C T revealed asymmetries and focai defects during stress consistent with CO s Xe rCBF studies, but Xe rCBF was more sensitive to baseline asymmetries and minimal flow changes due to its absolute quantification. Conelualons: I-IMPAO S P E C T allows accurate assessment of the brain topography involved in vasodilatory stress testing. Quantffieation provides additional information, however, and should be pursued with Xe S P E C T methods.
Pll EVALUATION OF OCULAR M~LANOMA: MRI OR ULTRASOUND? Kundan L. Gupt,% I~, D, Daisy Gupta, Bradey S. Shore, M.D Tulane University Medical Center, New Orleans, Louisiana Purpose: Delineating the optimal MR imaging sequences and usefulness of ultrasound in evaluating ocular melanoma. ~Materials and Methods: lntraocular melanoma is the most common intraocular malignancy in adults accounting for 80% of primary ocular malignancies. Magnetic resonance imaging was compared to ultrasound in the efficacy of evaluating, detecting characterizing 183 ocular m e l a n o m a cases. The findings, size of tumor, presence of r e t i n a l d e t a c h m e n t a n d hemorrhage are analyzed. Results: Heavily T-1 weighted sequences were considered more sensitive than either T-2 or proton density images in revealing information regarding deeper lesions and providing superior contrast resolution and tissues characteristics. Ultrasound, however, is invaluable in that it is cost effective, easily provided on an o u t p a t i e n t basis and provides higher resolution in detecting smaller lesions. Conc~lusiQn: MRI and US are both excellent imaging modalities in the medical care and foliow-up of the pre and post surgical ocular melanoma. Knowledge of each modalities effiG'tiy,and limitations facilitates optimal cost effective patient care.
PlO MRI OF TEMPORALLOBE EPILEPSy: COMPARISON OF S E Q ~ C E S . Authors:
LeoJ. Wolanqkv. M.D.. T. Kate, B.S., J. A. Mal~ian, M.D., B. K. Praman~ MD, D. Marks, M.D., J. Pak, M.D., H-J.Lee, M.D. UMDNJ, Newark, New Jei~ey
Ptwtmse: Because of growing In,crest in seizure surgery for intractable temporal Inl~ epilepsy, arcurato IVJ~Idingnesisof hippocampal scleresis Is esserdlal. Various studt5 have showed differences in r~ults, which have depeaded, in part, on techniques employed. The purpose of this study was to cmnpare the effectiveness of four differeat MRI sequences. The folinwingfour MRI sequences were compared: Thin-section3D Fomier Tramfform Spoiled Grant, t-Echo (SPGR) Tl-weighted images; High-resolution fast s0n-echa T2weighted images; Ceaventional sp'm-echo Balanced imas~; and Narrow-bandwidth (4 kHz) ¢onvmtio~l spin-echo T2-weigMedInmgrs. Each sequence was read separately by a reader banded to the ~a~msiz. R~ult~:
The most effective sequemo~ were T2-FSE (sensltivit y : 100%; spt¢lfldty : 80%)
and SPGR (mmedtivity: 86.7%; and spedlkity : $4.6%). Narrow handwldth 1"2tended to be lem effective (Semitivtty : 78.6%; specificity : 71.4%). Bahmced hnages had poor Semlelvltybee.ainuof poor distlm~n Ofklppocampus from vemrlde. Tl-weightod SPGR and T 2 - w ~ FSE tend to be the most effective seque~es for tha dlal~eets OfIdppeompal atrophy and appear to be ¢omplemeatary.
P12 T c - 9 9 m H M P A O BRAIN S P E C T IN C H I L D H O O D NARCOLEPSY: E V A L U A T I O N OF ITEM, Non-REM, AND T H E AWAKE STATE. Elmer C. San Pedro. M.D,, LM. Mountz, M.D., Ph.D., M. Wise, M.D., H.G. Lin, M.S. University of Alabarna at Birmingham, Birmingham, AL.
Put'nose: The inability of accurately identifying the exact moment of tracer injection in relation to the sleep-wake state contributes to conflicting reports in the medical literature regarding rCBF changes in narcolepsy. We ased videe/EEG/polygraphic monituring to dccurocnt sleep states prior to tracer injeedon. Methods: Brain SPECT imaging was performed after three separate injections of Te-99m HMPAO (over a 3-5 day period) to evaluate brain activity during wakefulness, REM and Non-REM sleep in two children with narcolepsy. Results: Semi-quantitative analysis showed significant increases in global rCBF during NOn-REM (20%) and during REM (9%) sleep as compared to the awake state in the first subject. There was also significant hemispheric perf~sicu asymmetry during Non-REM, R>L (8.5%) and during REM L>R (5%) as compared to wakefulness. The second subject developed minor bemispheric perfusion asymmetries during REM and NOn-REM when compared to wakefulness. Conclusions: Although there were only two subjects in this study, our results demonstrate that semiquamitative brain SPECT coupled with video/EEG/polygraphic monituring is able to detect rCBF changes in each stage of the sleep-wake cycle and may be helpful in future studies of rCBF changes in narcolepsy and other sleep disorders.