Chronological Changes in the Rotational Behavior in Response to Apomorphine Administration in 6-Hydroxydopamine Parkinsonian Rat

BACKGROUND: Apomorphine-induced rotational behavior of unilateral 6-hydroxydopamine (OHDA) lesioned rat is widely used to develop anti-Parkinsonian treatments including drugs, neuroprotective therapy, and neural graft. Time course of changes in rotational behavior after lesioning, however, has not been fully elucidated. The aim of this study was to observe the chronological changes in the rotational response and to find the optimal period when this model is used for investigation of various therapies. METHODS: 6-OHDA was stereotaxically delivered to the unilateral substantia nigra in 13 rats. Rotational responses to apomorphine administrations were counted in the rotomotor on 2, 4, 8, 12, and 14 weeks after lesioning. RESULTS: The total turns for two hours increased continuously up to eight weeks, and then plateaued. CONCLUSIONS: Apomorphine-induced rotations increase until eight weeks after 6-OHDA lesioning. Therefore, this Parkinsonian model should be used at least eight weeks after lesioning. Even though priming was not excluded as an explanation in the experiment, we reason that progressive degeneration of dopaminergic neurons may explain the chronological changes in rotational behavior.

THREE SUBTYPES OF TEMPORAL LOBE EPILEPSY: Clinical and Electrophysiological Characteristics of Medial, Anterior neocortical, and posterior lateral TLE

BACKGROUND: The clinical differentiation of hippocampal and neocortical temporal lobe epilepsy has practical value. And there seems no report concerning the clinical difference between anterior and posterior neocortical TLE. This study aims to determine whether there are important clinico-electrical differences between patients with hippocampal sclerosis(medTLE; MTLE) and those with anterior lateral temporal epileptogenic zone(anterior lateral TLE; ALTLE) and posterior lateral temporal one(posterior lateral TLE; PLTLE). METHODS: The case histories, interictal EEG, ictal semiology, ictal EEG, and memory lateralization in Wada test were compared statistically in the three groups (30 MTLE, 16 ALTLE, and 11 PLTLE). Lateral TLE(LTLE) was diagnosed when the radiologic studies showed discrete lesions lateral to collateral sulcus or the results of invasive study confirmed massive epileptogenic zones in the lateral temporal lobe. Whether the epileptogenic zone was located on the anterior or posterior to the line across the interpeduncular fossa of the midbrain made the differentiation between ALTLE and PLTLE. RESULTS: A history of febrile convulsion was more common in MTLE patients(p<0.001). An aura with auditory or visual components was unique in ALTLE and PLTLE. Oroalimentary and hand automatisms occurred more frequently in MTLE, while secondary GTCS and version were more frequent in PLTLE(p<0.01). Onset of secondary GTCS and version occurred later in seizures of MTLE(p<0.05). Memory lateralization in Wada test was highly possible in MTLE and PLTLE(p<0.01). Irritative zone was located on the posterior temporal electrode in 4 of 11 patients with PLTLE. Ictal onset with rhythmic beta activity was not observed in MTLE. CONCLUSION: There are a number of clinico-electrical differences among MTLE, ALTLE, and PLTLE.

Lateralizing value of interictal epileptiform discharge in temporal lobe epilepsy

OBJECTIVE & BACKGROUND: There have been reports on the lateralizing value of temporal lobe interictal epileptiform discharge(IED), yet it is a matter of debate till now. We studied our patients focusing on the degree of lateralization by which accurate lateralization was possible and also on the significance of bisynchronous IED(BIED) in the lateralization of temporal lobe epilepsy. METHOD: Fifty two patients were included in the study who were diagnosed as having medial temporal lobe epilepsy through video-EEG monitoring and brain MRI. Twenty four hour sleep-deprived interictal scalp EEG was checked for all of them. After that, we counted the number of independent IED(IIED) and BIED originating from anterior temporal areas. Then we tried to find a reasonable degree of IED above which correct lateralization of epileptogenic area was possible by using brain MRI as a standard. We also tried to find a significance of BIED in the lateralization of temporal lobe epilepsy by comparing the result excluding patients with BIED to that includig patients with BIED. RESULT: Lateralization of IED was over 80% accurate if the cutoff point was set at 70% and patients with BIED were included, but nearly 100% accurate of the cutoff point was set at 80% and patients with BIED were excluded. CONCLUSION: Influence of BIED on the accuracy of lateralization by IED is significant, and if the lateralization of IED is over 80% in patients with no BIED, the chance of true lateralization is very high.

Relationship between Functional Lateralization by Interictal Cerebral 18-FDG PET and by Intracarotid Amobarbital Procedure in Temporal Lobe Epilepsy

BACKGROUND: Many studies have reported that intracarotid amobarbital procedure (IAP) and 18-FDG PET of the brain are tests for focal functional integrity used in preoperative evaluation of temporal lobe epilepsy (TLE). And these tests have been used for assisting in lateralization of the epileptogenic focus. OBJECTS: We wanted to determine the relationship between functional lateralization by PET and by IAP and the role of those tests for lateralization in patients with TLE. METHODS & PATIENTS: All patients underwent long-term video/EEG monitoring, MRI of the brain, 18-FDG PET, IAP and some patients also had invasive EEG monitoring. The side of the epileptogenic focus was determined by interictal and ictal EEG, ictal semiology, SPECT, and MRI of the brain. Patients with mass lesion were excluded. Twenty seven had epileptogenic focus in the right temporal lobe and twenty six in the left temporal lobe. RESULTS: PET showed temporal lobe hypometabolism ipsilateral to the epileptogenic focus in 90% (48 of 53). Two patients showed bilateral temporal hypometabolism and two did normal findings. But these four patients showed Ipsilateral memory impairment to the epileptogenic focus in IAP. IAP revealed ipsilateral memory impairment to the epileptogenic focus in 70% (37 of 53) patients. Fifteen patients (28%, 15 of 53) showed ipsilateral temporal hypometabolism to the epileptogenic focus. Only one patient showed contralateral memory impairment to the epileptogenic focus but bilateral hypometabolism in PET. CONCLUSION: We find the convergence of data from MRI, EEG, IAP and PET to be very helpful in selection process of patients for temporal lobectomy.

Sensory Symptoms in Amyotrophic Lateral Sclerosis

Objective & BACKGROUND: It has been recognized that sensory symptom is one of the important exclusion criteria for diagnosis of ALS. However, sensory symptoms are occasionally complained of by some patients with ALS and there have been several reports on pathologic evidence of degeneration in sensory pathways. Therefore the authors performed the study to evaluate the sensory symptoms in patients with ALS and to analyze the cause of sensory abnormalities. Method : The clinical and laboratory data of seventy-seven ALS patients were obtained including history, neurologic examination, cervical magnetic resonance imaging, and electrophysiologic study. We evaluated the nature of subjective sensory symptoms and analyzed underlying causes for these abnormalities. Result : The onset age of 77 patients was between 19 and 75 years(mean age=49.5).. Twenty-five of 77 subjects (32.5%) complained of sensory symptoms such as paresthesia and tingling sensation. On neurologic examination Four patients (5.2%) had objective sensory change such as hypesthesia, decreased vibration sense. Five of 25 patients with sensory symptoms had superimposed underlying disease : cervical radiculopathy in 4, peripheral neuropathy in 1. Four of 37 patients showed central conduction defect on sensory evoked potential studies. Therefore in some patients, abnormalities in central sensory pathways are thought to be responsible for their sensory symptoms. Conclusion : The patients with ALS may have sensory abnormality although objective findings are rarely noted. Therefore coexistence of sensory symptoms does not exclude ALS. The presence of cervical radiculopathy, peripheral neuropathy and degeneration on central sensory pathways were thought to be the possible causes of their sensory symptoms.

Study on Clinical Courses of Vasculitic Neuropathies

Vasculitic neuropathy is a clinical manifestation affecting peripheral nerve in necrotizing vasculitis. It is generally regarded that natural courses are poor as there are abundant histologic and electrophysiologic evidences of axonal destruction. In this study, authors collected 15 cases of vasculitic neuropathy these six years and analyzed the data retrospectively to understand the clinical course. In 15 cases, the diagnosis of vasculitic neuropathy was made by the prominent clinical features, electrophysiological findings and sural nerve biopsies. Four cases were associated with polyarterits nodosa, one with systemic lupus erythematosus, two with rheumatoid arthritis, and one with polyangiitis overlap syndrome. However in other seven- cases the underlying dignoses were not made completely, but suspected some vasculitic conditions, such as isolated PNS vasculitis or undefined connective tissue disease. Electrophysiological studies showed mononeuritis multiplex in six, sensonmotor polvneuropathy in seven, and overlapped mononeuritis multiplex and polyneuropathy in two. Typical necrotizing vasculitis was found in nine out of twelve sural nerve biopsies. During the follow up period for up to two years, there was much improvement in ten, slight in three, and no improvement in two. In ten out of twelve patients prednisolone or prednisolone plus cyclophosphamide regimens showed improvement. Therefore authors thought that the clinical outcome was relatively fair in vasculitic neu . Ropathy when the therapy was started very early and the tirne factor between the onset and the uutiation of immunosuppressant therapy could be very important and critical.

The Diagnostic Values of Neurological Examination and Labratory Studies in the Patients of Myelopahty

Though diagnosis of myelopathy can be easily made by history and neurological examination, modern technologies, such as MRI and evoked potential study (EPS), have played an important role in making the anatomical and pathological diagnosis of myelopathy. To assess the accuracy of clinical diagnosis and the role of the laboratory studies, we prospectively studied 26 patients with myelopathy, admitted to S.N.U.H. We tried to decide, by clinical history and examination, the anatomical location and the pathological diagnosis, and compared them with final diagnosis. 1. The final diagnosis could be made in 23 out of 26 patients. 2. Of 17 patients with the initial clinical diagnosis of intramedullary lesion (IML), two patients turned out to have extramedullary lesions (EML). Final diagnosis could not be made in three patients, and imaging studies and EPS didn't reveal definite local lesions. In another group of nine patients with the initial clinical diagnosis of EML, three patients had IML. 3. The clinically suspected levels of lesions were shown to be accurate within one level in 20 out of 26 patients after MRI. 4. Clinical diagnosis was accurate in 18 out of 26 patients. 5. Among the laboratory tests, MRI helped localize the lesions and make the final diagnosis. EPS was most helpful in making a diagnosis of multiple sclerosis by finding out asymptomatic second lesions. Even with thorough work-up the etiologies of myelopathy in three patients could not be elucidated. 6. Review of wrong diagnosis showed that diagnostic errors were attributed to incomplete history taking or examination, misinterpretation of clinical data, and unusual presentations or unsuspected rare diseases. Therefore, the authors conclude that the physician's clinical examinations in the diagnosis of neurologic diseases are still valuable despite the technology of the laboratory studies is developing further in present days.

Clinical Follow-up Study of Myasthenia Gravis

The authors studied clinical features, thymus histology, acetylcholine receptor antibody titers and the responses to multiple modalities of treatment in a consecutive series of 151 patients to know the characteristics of myasthenia gravis in Korea and to clarify the selection of theraputic regimens. The MG subjects were enrolled in Seoul National University Hospital Myasthenia Gravis Registry and followed for at least over 12 months from 1986 to 1991. The overall clinical features were nearly the same as other previous reports in other country except that pure ocular MG group showed younger age of onset and no significant sexual difference. When we classified 151 MG subjects by several criteria. The most valid grouping variables were whether the thymoma was present or not and whether the symptoms were generalized or not. However there was no difference of clinical features when they were divided by age of onset. Therefore we thought that it may be reasonable to classify the MG subjects by a few variables listed above for it will be helpful for comparing therapeutic modalities, estimating the prognosis, and understanding the basic pathomechanisms underlying each subgroups.

A Retrospective Analysis on the Prognostic Factors of Brain Abscess

The medical records of fifty-seven patients uith intracranial abscess which had been admitted to the departrnents of neurology, neurosurgery, otolaryngology and pediatrics. In Seoul National University Hospital from 1983 to 1992 were reviewed. Mean age was 31.4 years, ranging from 3 to 66 vears. Male predominated with the ratio of 2.6: 1. Common predisposing conditions were hearrt disease, parameningeal infection such as chronic otitis media, paranasal sinusitis, pulmonary infections in order of frequency. Primary focus was not determined in 16% of cases. A wide range of organisms were encountered and aerobes were more frequently cultivated than anaerobes. In 56% of cases. Pathogens were not confirmed. The use of preoperative antibiotics was not significantly correlated with sterile cultures: Initial symptoms and signs uere usually nonspecific; headache in 89%, fever in 53%. Nausea and vomiting in 54%. Altered consciousness in 39%. Computed tomography was the most accurate and rapid diagnostic tool, and serial follow-up during the treatment was helpful in knowing whether the response to several treatment modalities was good or not. Of the fifty-seven cases, twenty-seven patients were operated; 17 patients underwent aspiration of the abscesses, and ten patients received resection of abscesses. Sixty three percents of surviving patients suffered from neurologic sequelae; most commonly epilepsy in 50%. The mortality rate among all treated patients was significantly related to the initial consciousness level and the number ol the abscesses, but not to the size ol lesion. Identification of organism, age or sex. Although non-surgical therapy is appropriate n some selected patients, surgical intervention should be considered, when the consciousness level deterates or the CT findings are aggravated after full dose of combination antibiotics.

Clinical Study on Spontaneous Lobar Intracerebral Hemorrhage

We investigated fifty four patients with spontaneous intracerebral lobar hemorrhage who were admitted to the Seoul National University Hospital Neurology Sercice during a period of five and a half years. Of these patients 25 (46.3%) had hypertension as the probable cause of hemorrhage Of the remaining cases, 12(22.2%) had other etiologies including 5 arteriovenous malforrnations. 3 aneurysms, 2 tumors, 1 Moyamoya disease and 1 superior sagittal sinus thrombosis, while 14(25.2%) had no apparent etiology. But some of them seemed to be due to cerebral amyloid angiopathy or occult vascular malformation. Parietal region was the most frequent site of hemorrage(23 cases, 42.6%). Six cases had multiple intracerebral hematoma. Common clinical manifestations were headache, vomiting, hemiparesis, seizure in order of frequency. Mortality rate was 16.7%, which was correlated with the size of hematoma (P<0.05) and consciousness level at the initial stage (p<0.05). But not with the presence of intraventricular or subarachnoid hemorrhage. Hypertension or age of onset.

Sturge-Weber Syndrome without Facial Nevus

This is a case report of a sixteen-year-old boy who has been suffering from throbbing headache since thirteen years of age. Neuroimaging investigations including brain CT and MRI demonstrated the characteristic features of Sturge-Weber syndrome: intracranial calcification, enlarged choroid plexus. And gyral enhancement. However, there was no facial nevus or focal neurological abnorrnality.

Combined Paraneoplastic Phenomena of Lambert-Eaton syndrome and Subacute Sensory Neuronopathy

No abstract available.

Pharmacokinetic comparison of two valproic acid formulations: a plain and a controlled release enteric-coated tablets

We investigated the single- and multiple dose pharmacokinetics of a new controlled-release formulation (Orfil retard enteric coated tablet) of valproic acid in comparison with those of the plain tablet as a reference. Twelve healthy volunteers were given each formulation of 300 mg in the single-dose study. In the steady-state multiple-dose study, twelve epileptic patients received 1200 mg/day of the reference drug (300 mg 9 AM, 300 mg 3 PM, 600 mg 9 PM) and the test formulation (600 mg 9 AM, 600 mg 9 PM) with at least one week interval in cross-over manner. The AUC values of the test controlled release formulation were 91.7% (95% confidence interval: 78.4-100.4%) of the reference drug in the single-dose study and 98.2% (95% confidence interval: 86.2%-109.9%) in the steady-state study. The AUC's of the two formulations were not significantly different by ANOVA test. The Cmax and Tmax values of the test formulation were significantly different from the values of the reference in single-(Tmax: 158.4%, Cmax: 52.5% of the reference) and multiple-dose study (Tmax: 153.5% of the reference). The MRT values of the test formulation were also significantly greater (129.4% of the reference) in the single-dose study. Regarding the controlled-release characteristics of the test formulation, fluctuation index and percentage fluctuation of the twice a day dosage regimen of the test formulation were comparable with those of the thrice a day dosage regimen of the conventional tablet. Area deviation was even smaller in the test regimen of the controlled release formulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Characteristics of Non-compressive Myelopathy

The authors evaluated those 47 subjects with non-compressive myelopathy who were admitted to Department of Neurology SNUH from January 1988 to December l99Q to know the clinical characteristics and the association with multiple sclerosis. By clinical courses, the patients could be divided into three groups: (l) the first group (n&10) who had acute onset and plateau course of the illness with improvement of variable degrees, (2) the second group (n&21) who had chronic progressive course, (3) the third group (n&16) who had relapsing and remitting course. The sensory dysfunctions were present in 9096 of the first and second group and in 93% of the third group respectively, but motor and sphincter dysfunctions were more frequent in the first group (90%) than in the second (68%) or third groups (75%), The level of myelopathy was most common in thoracic spinal cord which was shown in 79% of all patients, especially in 90% of patients of second group. When the authors evaluated those 47 subjects with having non-compressive myelopathy clinically, 9 out of them(19.0%) revealed to have other lesions in brainstem, cerebrum, optic nerve, and were diagnosed to have clinically probable multiple sclerosis. During follow-up periods, 2 additional subjects of the third group developed visual dysfunction and could be diagnosed as multiple sclerosis. So we could make the diagnosis of multiple sclerosis in 11 out of 47 patient(23.0%). Therefore the authors thought that we should take into account the diagnosis of multiple sclerosis in the subjects with the only myelopathy clinically and by diagnostic study. In spite that those rarely developed into multiple sclerosis.

Relative Bioavailability of Controlled Release Carbamazepine and Pharmacokinetic Properites: Steady-State Study

The relative bioavailability amd palsma level fluctuation of controlled release carbamazepine (carbamazepine CR, CBZ CR, Tegretol CR) to the regular product (Carbamazepine RR, CBZ RR, Tegletol RR) were studied in 12 patients who were taking stable dose of carbamazepine for more than six weeks. Fixed dosage regimen (400 mg every 12 hours) of both products was administered in a random cross over manner at least for four days. After reaching steady-state, serial blood samples were drawn after last dose administration. Plasma carbamazepine levels were analysed by fluorescence polarizing immunoassay. The controlled lelease products showed lower area under the concentration time curve (AUC; 89.7)20.0 ug/ml/hr) than that (107.1)13.2 ug/ml/hr) of the regular products (p<0.01), and also showed low peak plasma level (CR;848)l.93ug/ml, RR;10.57+1.55 ug/ml). However. Fluctuation of plasma drug level during dose interval was slightly less in controlled release products compared with carbamazepine regular products in the respect of various indices such as percent fluctuation, fluctuation index and area deviation from mean level. However those parameters did not show no statistical singificance between two products except area diviation (p<0.01). Though the controlled relase product showed slightly less fluctuation during dose interval, this seemed to be the expense of incomplete bioavailability. As a conclusion, the dose correction should be made according to the relative bioavailability of controlled release formulation if switching of the formulation from regular to controlled release form would be needed. However it could not be proved that controlled release fromulation had less fluctiuation during dose interval in this study. More detailed studies should be pursued to show the evidence of significant superiority of currently marketing controlled release formulation to the regular one.

Leptomeningeal Metastasis Presented before Primary cancer

Leptomeningeal metastasis(LM) usually occurs in patients with previous cancer. But rarely it can be the first manifestation of cancer. We analyzed primary tumors and early clinical findings in 12 patients in whom LM was the presenting sign of cancer. Primary tumors were lung cancer in 5 cases, stomach cancer 1, lymphoma 1 and unknown 5. Most patients, previously healthy, developed progressive headache which was followed by symptoms and signs involving multiple neuraxis. Major symptoms on admission were headache, nausea, vomitting, visual dimmness, diplopia, hearing disturbance and the major neurologic deficits were papilledema, ocular motor palsy, decreased DTR and neck stiffness. From these clinical findings and CSF test, initially LM was suspected in only 6 patients. In the remaining 6 patients, initial diagnosis were tuberculosis meningitis(3), benigh intracranial hypertension(2) and adjustment disorder(1). In addition to cytology, which was positive in 9 cases, CSF carcinoembryonic antigen(CEA) and neuroimaging played an important role in the early diagnosis of LM. Despite whole brain radiation therapy, all patients worsened and expired 2 weeks-10weeks(median survival, 3 weeks) after the diagnosis.

The effect of hyperglycemia on lipid peroxidation in the global cerebral ischemia of the rat

To investigate the influence of hyperglycemia on ischemic brain damage, we measured brain ATP, lactate and malondialdehyde (MDA) levels in global cerebral ischemic models of Wistar rats. We induced global cerebral ischemia by the 4-vessel occlusion method. After 30 or 60 min of occlusion, and after 30 min of reperfusion, we measured brain ATP, lactate and MDA levels. During the ischemic period, brain ATP levels decreased to 30-70% of sham groups both in normoglycemic and hyperglycemic groups. But during the reperfusion period, the recovery rate of ATP levels was significantly lower in the hyperglycemic than in the normoglycemic groups (p less than 0.05). After 60 min of global ischemia, brain lactate increased much more in the hyperglycemic than in the normoglycemic group, and, during reperfusion, was washed out slowly in the hyperglycemic group. The MDA level, a parameter of lipid peroxidation, increased more in the hyperglycemic group than in the normoglycemic group during reperfusion periods (p less than 0.05). We conclude that hyperglycemia increases lactate accumulation, delays the recovery of energy metabolism, and enhances the lipid peroxidation in the transient global ischemia of rat brain. These findings may suggest the harmfulness of hyperglycemia in clinical cerebral ischemia.

Changes of Acetylcholine Receptor Antibody Concentration and Disease Severity in Myasthenia Gravis

The authors have measured the anti-AChR antibody concentration in sera of 20 myasthenia gravis and of 17 normal or other neurological diseases, to establish the radioimmunoassay(RIA) system for the AChR antibody test and to evaluate the possible relationships between changes in AChR antibody titer and clinical severity of myasthenia gravis. Significant AChR antibody titers(more than 0.04 pmol/ml) were found in 17 out of 20 myasthenia gravis (85.0%) and in 1 out of 17 norrnal or other neurological diseases (5.9%). When those 20 myasthenia gravis were classified into Ossennan's clinical stage, the AchR antibody titer rarlged from 0 to 059 pmole/ml in grade I, from 0.01 to 0.68 pmole/ml in grade IIA, from 0.15 to 1.05 pmole/ml in grade II and from 0.22 to 1.03 pmol/ml in grade III, and showed relatively good correlation with clinical severity of myasthenia gravis (Pearson correlation coef{icient 0.76). However the correlation proved to be better when the AChR antibody titers were compared with the functional activities of myasthenia gravis according to Drachman s proposal. Also the authors thought that the AChR antibody tests would be invaluable in the diagnosis of myasthenia gravis and that the extensive studies would be needed to establish the normal value of the binding AChR antibody in our laboratory.

Clinical Phenotypic Patterns of Ophthalmoplegia Plus with Ragged Red Fiber

Chronic progressive ophthalmoplegia(CPEO) is a vague clinical entity, which needs further understanding and there is still intense controversy about the classification on the Syndrome of Progressive External Ophthalmoplegia. In our country two cases of similar disease were reported with the title of oculocraniosomatic disease and CPEO with ragged red fiber. Authors experienced a 39 year-old woman with typical Kearns-Sayre syndrome(KSS) and a 44 year-old man with ophthalmoplegia plus syndrome. The case with Kearns-Sayre syndrome had an invariable triad of 1) chronic progressive external ophthalmoplegia and onset before 20 years of age, 2) retinal pigmentary degeneration of salt & pepper pattern and 3)mitochondrial abnormalities with additional findings of increased cerebrospinal fluid protein and cerebellar ataxia rhe other case with ophthalmoplegia plus with ragged red fiber syndrome had similar symptomatology to Kearns-Sayre syndrome except for typical retinal pigmentary degeneration. Both cases showed electromyographic myopathic findings and typical histopathologic features as ragged red fiber and paracrystalline mitochondrial aggregations. Therefore authors would say that these clinical different phenotypes of mitochondrial abnormality should be understood in detail by the biochemical investigations.

MR imaging of the internal carotid artery in ischemic cerebrovascular disorders: clinical and angiographic correlation

This study was intended to correlate the appearance of the cavernous segment of the carotid artery on MR images with the presence of significant stenosis or occlusion of the cervical carotid artery as seen on angiograms in 37 patients with cerebrovascular disorders who had brain MRI and arteriography. Three patients demonstrated an isointense signal within the carotid artery's cavernous segment, correlating with complete carotid occlusion as seen angiographically. Ten patients had variable signal intensity and/or luminal narrowing in the carotid siphon; seven of these findings correlated with angiographic evidence of carotid occlusion, while carotid branch occlusion was seen angiographically in the other three. The demonstration of normal signal void within a normal-appearing cavernous segment of the internal carotid artery in the remaining 24 patients correlated with an absence of significant stenosis within the cervical segment in 21 patients. In the remaining three, significant disease of the internal carotid artery was found. Isointensity or luminal irregularity within the intracranial carotid artery can indicate complete occlusion or slow flow. The presence of normal flow void in the intracranial segment does not exclude significant abnormality of the cervical segment of the carotid artery.