[Clinical relevance of cranial CT under emergency conditions--basic neuroradiologic investigations]

Brain CT Findings in Patients with First-Onset Seizure Visiting the Emergency Department in Mashhad, Iran

Introduction

Regarding the complications and costs of CT imaging for patients, this study aimed at investigating the necessity of CT scans in patients visiting the emergency unit with first-onset seizure.

Methods

One hundred patients who had experienced their first seizure were enrolled. Their CT scan was studied, and based on the radiology report, the type of probable pathologies and their percentage were determined.

Results

The patient’s mean age was 39.78±17.43 yrs. CT scan abnormalities were reported in 27 cases as follows: nonspecific senile changes in 11 (40.7%), encephalomalacia in 3 (11.1%), acute infarct in 5 (18.5%), lacunar infarct in 3 (11.1%), mass-like lesion in 4 (14.8%) and cerebral venous thrombosis (CVT) evidence in 1 (3.7%). Acute infarct and mass-like lesions were seen together in the CT scan of one patient. In only 9 of the 27 abnormal CT scans, the findings were in accordance with seizure consisting of an acute infarct, mass-like lesion, and CVT evidence.

Discussion

It seems that performing a CT scan in all patients referring to the emergency department with a first-onset seizure is not necessary.

Magnetic resonance imaging versus computed tomography for detection of acute vascular lesions in patients presenting with stroke symptoms

BACKGROUND

Magnetic resonance imaging (MRI) is increasingly used for the diagnosis of acute ischaemic stroke but its sensitivity for the early detection of intracerebral haemorrhage has been debated. Computed tomography (CT) is extensively used in the clinical management of acute stroke, especially for the rapid exclusion of intracerebral haemorrhage.

OBJECTIVES

To compare the diagnostic accuracy of diffusion-weighted MRI (DWI) and CT for acute ischaemic stroke, and to estimate the diagnostic accuracy of MRI for acute haemorrhagic stroke.

SEARCH STRATEGY

We searched MEDLINE and EMBASE (January 1995 to March 2009) and perused bibliographies of relevant studies for additional references.

SELECTION CRITERIA

We selected studies that either compared DWI and CT in the same patients for detection of ischaemic stroke or examined the utility of MRI for detection of haemorrhagic stroke, had imaging performed within 12 hours of stroke onset, and presented sufficient data to allow construction of contingency tables.

DATA COLLECTION AND ANALYSIS

Three authors independently extracted data on study characteristics and measures of accuracy. We assessed data on ischaemic stroke using random-effects and fixed-effect meta-analyses.

MAIN RESULTS

Eight studies with a total of 308 participants met our inclusion criteria. Seven studies contributed to the assessment of ischaemic stroke and two studies to the assessment of haemorrhagic stroke. The spectrum of patients was relatively narrow in all studies, sample sizes were small, there was substantial incorporation bias, and blinding procedures were often incomplete. Amongst the patients subsequently confirmed to have acute ischaemic stroke (161/226), the summary estimates for DWI were: sensitivity 0.99 (95% CI 0.23 to 1.00), specificity 0.92 (95% CI 0.83 to 0.97). The summary estimates for CT were: sensitivity 0.39 (95% CI 0.16 to 0.69), specificity 1.00 (95% CI 0.94 to 1.00). The two studies on haemorrhagic stroke reported high estimates for diffusion-weighted and gradient-echo sequences but had inconsistent reference standards. We did not calculate overall estimates for these two studies. We were not able to assess practicality or cost-effectiveness issues.

AUTHORS' CONCLUSIONS

DWI appears to be more sensitive than CT for the early detection of ischaemic stroke in highly selected patients. However, the variability in the quality of included studies and the presence of spectrum and incorporation biases render the reliability and generalisability of observed results questionable. Further well-designed studies without methodological biases, in more representative patient samples, with practicality and cost estimates are now needed to determine which patients should undergo MRI and which CT in suspected acute stroke.