High-signal cortical lesions are observed on T1-weighted images in cases of brain infarct. Histological examination has demonstrated these to be "cortical laminar necrosis", without haemorrhage or calcification. We report serial MRI in this condition in 12 patients with brain infarcts. We looked at high-signal lesions on T1-weighted images, chronological changes in signal intensity and contrast enhancement. High-signal cortical lesions began to appear about 2 weeks after the ictus, were prominent at 1-2 months, then became less evident, but occasionally remained for up to 1.5 years. They gave high signal or were isointense on T2-weighted images and did not give low signal at any stage. Contrast enhancement of these lesions was prominent at 1-2 months, and less apparent from 3 months, but was seen up to 5 months.

The purpose of this study was to describe magnetic resonance findings of intradural spinal canal secondaries and to select the best way of investigating this condition. Thirty patients with a known malignancy [breast carcinoma (n = 14), lung carcinoma (n = 10), other sites (n = 6)] and unexplained neurologic signs were studied with pre- and post-contrast T1-weighted images and T2-weighted images. Cerebrospinal fluid cytology was available in 16 patients and positive in 11 patients. In all the patients, post-contrast T1-weighted images demonstrated abnormal enhanced lesions. Most of them were nodular, located on the conus medullaris and the cauda equina. Few lesions appeared at the thoracic or cervical levels, as nodular or thin areas of enhancement. Pre-contrast T1-weighted sequences failed or were equivocal to detect the lesions. Eighteen of 30 patients had cerebral metastases. Fourteen had osseous metastases. In conclusion, post-contrast T1-weighted sequence is the optimal modality for the diagnostic of intradural spinal canal metastases. Axial and coronal images may be a useful adjunct to precise anatomic changes. T1-weighted and T2-weighted sequences remain necessary when further information is expected on vertebra or soft tissue.

No abstract

The aim of this study was to describe magnetic resonance imaging (MRI) findings in patients with medically intractable epilepsy and to compare different magnetic resonance (MR) sequences in order to establish a dedicated and shorter scan time imaging protocol of choice. One hundred and twenty patients with seizures that were refractory to medical treatment were assessed by MRI with spin-echo (SE) T1, fast spin-echo (FSE) T2, fluid-attenuated inversion recovery (FLAIR), inversion recovery (IR) and contrast-enhanced T1 SE sequences. Pathological scans were acquired in 78 patients. Hippocampal sclerosis was detected in 30 patients (25%), cerebral, tumoral, mass lesions in 12 patients (10%), vascular malformations in nine patients (7.5%), cortical infarcts in eight patients (6.7%), cerebral infections in four patients (4.2%) and developmental disorders in 15 patients (12.5%). The most common location of the lesions was the temporal lobe (60%). Coronal, thin (slice thickness 4-5 mm) images have proven to be the most useful in the assessment of the hippocampus. FLAIR and IR are particularly useful in the detection of lesions abutting cerebrospinal fluid (CSF) spaces and developmental disorders, respectively, while T1 SE sequences before and after the intravenous administration of gadolinium offer great facility in identifying space-occupying lesions and infections. MRI is the most important diagnostic tool for the assessment of epileptogenic foci, thus playing the primary role in indicating the type of treatment to be applied.

No abstract