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J H Pexman

Publications and source records attributed to J H Pexman.

At least 19 recordsLinked to original sources
PubMed2001

Hyperdense sylvian fissure MCA "dot" sign: A CT marker of acute ischemia.

BACKGROUND AND PURPOSE: The hyperdense appearance of the main middle cerebral artery (HMCA) is now a familiar early warning of large cerebral infarction, brain edema, and poor prognosis. This article describes the hyperdensity associated with embolic occlusion of branches of the middle cerebral artery in the sylvian fissure (MCA "dot" sign). We define it and determine its incidence, diagnostic value, and reliability. METHODS: CT scans performed on patients with acute ischemic stroke within 3 hours of symptom onset were analyzed for signs of thromboembolic stroke and evidence of early CT ischemia. Two neuroradiologists and 2 stroke neurologists initially blinded to all clinical information and then with knowledge of the affected hemisphere evaluated scans for the presence of the MCA dot sign, the HMCA sign, and early MCA territory ischemic changes. RESULTS: Of 100 consecutive patients who presented within 3 hours of symptom onset, 91 were considered at symptom onset to have anterior circulation stroke syndromes. Early CT ischemia was seen in 74% of these baseline CT scans. The HMCA sign was seen in 5% of CT scans, whereas the MCA dot sign was seen in 16%. All patients then received intravenous tissue plasminogen activator. All 5 patients with an HMCA sign, including 2 with an associated MCA dot sign, were either dead or dependent at 3 months. The 14 patients with an MCA dot sign alone were independent at 3 months in 64% of cases, compared with 50% without the sign (Fisher's exact test P:=0.79). Balanced kappa statistics for both the HMCA and the MCA dot sign were in the moderate to good range when the stroke symptom side was given. CONCLUSIONS: The MCA dot sign is an early marker of thromboembolic occlusion of the distal MCA branches seen in the sylvian fissure and is associated with better outcome than the HMCA sign.

Acute Disease↗
PubMed2001

Use of the Alberta Stroke Program Early CT Score (ASPECTS) for assessing CT scans in patients with acute stroke.

BACKGROUND AND PURPOSE: Clinicians are insecure reading CT scans by using the one-third rule for acute middle cerebral artery stroke (1/3 MCA rule) before treating patients with recombinant tissue plasminogen activator. The 1/3 MCA rule is a poorly defined volumetric estimate of the size of cerebral infarction of the MCA. A 10-point quantitative topographic CT scan score, the Alberta Stroke Program Early CT Score (ASPECTS), is described and illustrated. A sharp increase in dependence and death occurs with an ASPECTS of 7 or less. We describe how to use ASPECTS and why it works with CT scans obtained on all commonly used axial baselines. We also describe interobserver reliability among clinicians from different specialties and with different experience in reading CT scans in the context of acute stroke. METHODS: The six physicians who developed ASPECTS answered a questionnaire on precisely how they interpret and use ASPECTS. The ASPECTS areas as interpreted by these physicians were compared with one another and with standards in the literature. kappa statistics were used to assess the interobserver reliability of ASPECTS versus the 1/3 MCA rule. RESULTS: The exact methods of interpretation varied among the six individual observers, with either a 3:3 or 4:2 split on the specific questions. The overall interobserver agreement was good compared with that of the 1/3 MCA rule. Normal anatomic vascular and interobserver variations explain why ASPECTS can be applied with different CT axial baselines. CONCLUSION: ASPECTS is a systematic, robust, and practical method that can be applied to different axial baselines. Clinician agreement is superior to that of the 1/3 MCA rule.

Aged↗
PubMed1994

Computed tomography evaluation of patients with chronic headache.

OBJECTIVE: To determine whether the rate of detecting a tumour, arteriovenous malformation (AVM) or aneurysm with the use of enhanced or unenhanced computed tomography (CT) is significant in patients with chronic headache and to calculate the cost. DESIGN: Case series. SETTING: Chronic headache clinic at a tertiary care referral centre. PATIENTS: All 373 consecutive patients with chronic headache (284 women, 89 men) referred for CT scanning from May 1987 to October 1992 who met one or more of the following criteria: increased severity of symptoms or resistance to appropriate drug therapy (287 patients [76.9%]), change in characteristics or pattern of headache (78 [20.9%]) or family history of intracranial structural lesion (8 [2.1%]). INTERVENTIONS: CT scans of the head were enhanced with nonionic contrast medium (292 scans), were unenhanced (70) or involved both methods (40). OUTCOME MEASURES: Number and nature of minor and major findings, and total price per scan. RESULTS: Of the 402 CT scans 14 (95% confidence interval [CI] 7 to 21) revealed minor findings that did not alter patient management: infarct (9 scans), cerebral atrophy (2), cavum vergae (1), hyperostosis frontalis interna (1) and communicating hydrocephalus (1). Four scans (95% CI 0 to 8) showed significant lesions: osteoma (2), low-grade glioma (1) and aneurysm (1); only the aneurysm was treated. There were no cases of AVM. An unenhanced scan cost $82.63 and an enhanced scan $204.05. The cost per significant finding was over $18,000. In all, it cost $74,243 to find one treatable vascular lesion. CONCLUSIONS: The detection rate of CT scanning in patients with chronic headache is similar to that expected in the general population, provided the neurologic findings are normal. The cost of detecting intracranial lesions in this patient population is high [corrected].

Adolescent↗
PubMed1994

Cognitive functioning in long-term survivors of high-grade glioma.

In a pilot study, two groups of patients with malignant glioma underwent sequential neuropsychological evaluations after successful tumor treatment. Group 1 included nine patients treated from 1981 to 1985; all patients received irradiation and eight underwent chemotherapy. The baseline neuropsychological assessment was performed 1 to 63 months after tumor diagnosis, with follow-up evaluations at irregular intervals over the next 3 to 7 years. Six patients in Group 1 exhibited impairment on most measures at baseline; subsequently, two patients developed profound cognitive impairment. Initially, three patients functioned in the average range on most tasks; thereafter, two deteriorated on one measure each. Group 2 was ascertained prospectively and included 16 patients treated from 1985 to 1987, all of whom received irradiation and chemotherapy. The first evaluation was performed 18 months after diagnosis, then every 6 months for 2 years, and then yearly. Compared to a control group, those in Group 2 had significant cognitive impairment at baseline. Cognitive performance did not change over the next 12 months in 10 patients who remained free of tumor, but within 2 years of baseline testing, deterioration on specific tasks was evident in two of seven disease-free survivors. When last tested, five of six disease-free survivors had deteriorated on one or more measures. Unlike Group 1, severe global cognitive impairment was not seen, perhaps because Group 2 was followed for a shorter time. Verbal and nonverbal composite scores derived from intelligence quotient (IQ) tests showed less impairment at baseline than did other measures and were more likely to remain stable subsequently. Verbal memory and sustained attention were the most impaired at baseline, and verbal learning and flexibility in thinking showed the greatest tendency to decline over time. Cognitive functioning in survivors of high-grade glioma is best measured and monitored by tests that probe a broader spectrum of abilities than IQ. Neuropsychological measures used in this analysis lacked sensitivity at the lower end of the impaired range. Future studies should use tests better able to discern cognitive differences at low performance levels. Based on this experience, the authors conclude that most long-term survivors of high-grade glioma will have significant cognitive difficulties, usually evident by the first assessment; some patients will develop profound impairment years later, and few are capable of fully independent living.

Adult↗
PubMed1988

Steroid-induced CT changes in patients with recurrent malignant glioma.

The magnitude and time course of steroid-induced CT changes were analyzed in 11 patients with recurrent malignant glioma. CTs were obtained before and at regular intervals after starting dexamethasone (16 mg/d). Midline shift, ventricular compression, edema, enhancement intensity, and the size of the enhancing mass often improved with steroid treatment. Improvement occurred within 2 weeks in most instances. Changes in the volume of the enhancing tumor were assessed quantitatively in eight patients. In six, the mass was smaller after 2 weeks of steroid therapy, and in two the reduction approached 50%. Steroid-induced CT changes can mimic treatment responses. If steroids are necessary for symptom control, patients should be taking these medications for 2 weeks before a baseline CT is obtained and investigational treatment started.

Adult↗
PubMed1985

Postoperative contrast enhancement in patients with brain tumor.

Contrast enhancement resulting from surgical trauma may mimic residual enhancing tumor, thereby complicating the interpretation of postoperative computed tomographic scans. We assessed the natural history of postoperative enhancement in 10 patients with brain tumor. Contrast enhancement distinguishable from residual enhancing tumor appeared along the operative margin following tumor resections but not lobectomies. Enhancement appeared as early as the fifth postoperative day, was most intense at two weeks, and persisted for several months. Prior to the fifth postoperative day, enhancement reflected residual tumor. Edema and artifacts were more prominent on the first and second postoperative days than on the third and fourth. We recommend that postoperative computed tomographic scans to assess residual enhancing tumor be performed on the third or fourth postoperative day. This timing avoids postoperative enhancement and minimizes interpretative difficulties caused by artifacts.

Adult↗