Severe amnesia after hypoglycemia. Clinical, psychometric, and magnetic resonance imaging correlations.

OBJECTIVE: To determine the correlation between clinical, psychometric, and magnetic resonance imaging (MRI) findings after an episode of hypoglycemic coma resulting in amnesia. RESEARCH DESIGN AND METHODS: Detailed psychometric assessment, especially memory testing, performed with MRI in a man with severe amnesia after hypoglycemic coma. RESULTS: Psychometric testing confirmed impaired immediate recall. MRI findings were consistent with a lesion in the left temporal lobe. CONCLUSIONS: This is the first description of MRI in determining the neurological damage in hypoglycemic coma.

Magnetic resonance imaging in schizophrenia: altered brain morphology associated with P300 abnormalities and eye tracking dysfunction.

This study was designed to investigate whether auditory P300 event-related potential and smooth pursuit eye-movement abnormalities in schizophrenia are associated with brain structural changes measured using magnetic resonance imaging (MRI). Serial coronal MRI scans obtained from 31 schizophrenic subjects and 33 volunteer controls were analysed by a rater who had no knowledge of the subjects' diagnoses. The brain areas measured bilaterally were the temporal lobe, hippocampus, amygdala, parahippocampal gyrus, head of caudate, cingulate cortex, frontal cortex, and the lateral ventricles. The area of the third ventricle, the thickness of the corpus callosum, and the intracranial area were also measured. Auditory P300 and eye tracking performance were recorded on all subjects. There was a significant increase in the latency and a reduction in amplitude of the P300 in the schizophrenic group. Only in the schizophrenic group was P300 latency correlated negatively with the area of the right and left cingulate cortex and positively with the difference in size between the right and left amygdala. In the subgroup of schizophrenic subjects whose P300 latency was greater than 2 standard deviations above the control mean, the area of the left cingulate cortex was significantly smaller than in controls, and the absolute right-left difference in the area of the amygdala was significantly increased. Eye tracking dysfunction in schizophrenia was not related to changes in the amygdala or cingulate cortex but was significantly correlated with enlargement of the lateral ventricles. Schizophrenic subjects with poor eye tracking had significantly larger lateral ventricles than controls. Eye tracking dysfunction, but not P300 abnormality, was correlated with the severity of both positive and negative symptom of schizophrenia. These findings demonstrate that psychophysiological abnormalities are associated with altered brain structure in schizophrenia.

NMR tissue characterization in intracranial tumors: preliminary results.

Nuclear magnetic resonance (NMR) has been shown to have high sensitivity for detecting intracranial pathology. A study was devised to determine what information about tissue characteristics can be derived from steady-state free-precession NMR images alone and when compared with computed tomographic (CT) scans. The flow-dependent sequences allow diagnosis of intrinsic vascular lesions. Whereas precise characterization of some pathologic groups such as fat-containing tumors is possible, other important groups cannot be clearly differentiated. Preliminary findings suggest that it may be possible to predict the texture of extrinsic tumors from their NMR signals.

Craniovertebral junction pathology: assessment by NMR.

In nuclear magnetic resonance (NMR) studies choice of imaging plane is achieved by a variety of methods that restrict data collection to the desired region. This means that the additional perspectives of direct sagittal and coronal views are possible. In sections traversing the brainstem and cervical cord the neural tissue is clearly seen contrasted against the surrounding cerebrospinal fluid (CSF). NMR studies of a wide variety of lesions in the vicinity of the craniovertebral junction, including congenital and acquired bony deformities, intrinsic tumors, and syringomyelia, are evaluated. It is concluded that the assessment of clinical problems involving this region is simplified by NMR imaging and that its use will probably allow more invasive procedures to be avoided.

The application of NMR imaging to the evaluation of pituitary and juxtasellar tumors.

Nuclear magnetic resonance (NMR) imaging was used to evaluate pituitary and juxtasellar tumors in 37 patients representing a wide range of pathology. The value of the multiplanar facility of NMR is emphasized in providing accurate volumetric information and establishing the topographical relation of tumors to adjacent structures. Current limitations of the method and possible future developments to improve diagnostic precision are discussed.

NMR imaging in the evaluation of orbital tumors.

The application of nuclear magnetic resonance (NMR) imaging to the diagnosis of orbital space-occupying lesions was studied in group of 28 patients with a wide range of pathology. The NMR findings in six patients are illustrated. The results of the NMR scans are compared with the information that can be derived from conventional neuroradiologic procedures, including computed tomography. The value of the multiplanar facility of NMR is emphasized. It provides accurate volumetric information and establishes the precise topographical relationships of tumors to normal structures. The muscle cone and the optic nerve can be identified in the axial, coronal, and sagittal planes. Current limitations of the method and possible future developments to improve diagnostic precision are discussed.

NMR imaging in the recognition of giant intracranial aneurysms.

Most giant aneurysms present clinically as intracranial mass lesions. Many contain an organized lamellated thrombus with only a small eccentric lumen remaining that can be opacified at angiography. Four patients with such aneurysms were studied using flow-dependent nuclear magnetic resonance scanning sequences. The aneurysms show a smooth rounded margin, and the thrombus within is clearly distinguishable from the blood flowing through the patent lumen, which gives a low signal. By using different scan sequences it is possible to prove that the area of low signal is indeed fluid in rapid motion, thus confirming the diagnosis.

Brain hydration during alcohol withdrawal in alcoholics measured by magnetic resonance imaging.

Twenty-seven patients had a first Magnetic Resonance Imaging (MRI) scan 1-3 days after stopping drinking and a second approximately 2 weeks later with no change in whole brain T1 or T1 in selected brain areas. Six patients whose first scan was over 36 h after the last drink underwent an increase in whole brain T1 in the interval to the second scan. The later the first scan was performed the greater was the increase in T1. These results are compatible with a very early fall in brain water immediately on cessation of drinking (perhaps due to a rebound increase of vasopressin activity) with a return to 'baseline' after two weeks. A third scan after discharge from hospital in 23 individuals who had abstained from alcohol or drank very little did not reveal any further significant change in brain T1.

An observation of increased contrast due to both T1 and T2 weighting in a synthetic image.

An observation was made that subtracted images generated by an SR/IR interleaved pulse sequence on a low field strength magnetic resonance imager (M&D Technology Ltd, Aberdeen, Scotland) contained contrast between pathological and normal tissues that was not explained by either T1 or T2 weighting alone. A theoretical model for this image has been derived and its validity confirmed by phantom experiments. It is shown that the subtracted image is dependent on the product of T1 and T2 prolongation for contrast. This type of image might be of use in screening for unknown pathologies and such techniques may shorten routine patient imaging times.

The installation of a commercial resistive NMR imager.

It has been demonstrated that a relatively low-cost resistive NMR imager can be installed in a normal hospital environment without many major or expensive modifications. The magnet can be adjusted to give adequate uniformity and there is sufficient RF shielding to give good quality clinical images (Fig. 3). The fringe field of the magnet of this system, which operates at the lowest field strength of any commercial NMR imager, does not present a problem to imaging unit staff (NRPB, 1984). The long term reliability and detailed specifications with regard to image quality have yet to be determined. These will be determined whilst the imager is being used for clinical studies as part of the national clinical evaluation of NMR imaging supported by the Medical Research Council.

Correlation of human NMR T1 values measured in vivo and brain water content.

A relationship has been demonstrated between nuclear magnetic resonance (NMR) longitudinal relaxation times (T1 values) obtained in vivo in both normal and oedematous (peritumoral) brain tissue, and measurements of brain water obtained by gravimetric analysis of operative samples. Significant correlations were found in seven patients in both cortex (r = 0.97, P less than 0.001) and white matter (r = 0.92, P less than 0.001). These findings suggest that NMR may prove a useful technique for monitoring brain oedema.

Nuclear magnetic resonance imaging of the knee: examples of normal anatomy and pathology.

Nuclear magnetic resonance images of the knee were obtained from three normal volunteers and from two patients. The pathology included an osteosarcoma of the distal femur and a fracture of the tibia. Steady State Free Precession (SSFP) techniques were used with a 0.15 Tesla resistive type magnet. Normal anatomy was well displayed and the size of the osteosarcoma was accurately predicted. Using SSFP techniques, the blood in the knee joint was not visualised, but the underlying tibial fracture was clearly outlined.

Early delayed radiation injury to the brainstem after radiotherapy for lymphoma of the tongue and neck.

We describe a case of severe early delayed radiation injury to the brainstem after curative radiotherapy using a standard therapeutic irradiation regimen for lymphoma of the base of the tongue with cervical lymphadenopathy. Magnetic resonance imaging showed a lesion in the brainstem corresponding to an area of neural tissue coincidentally irradiated. A literature review of this rare complication is presented.

The use of nuclear magnetic resonance in the diagnosis of lateral canal entrapment.

The use of nuclear magnetic resonance (NMR) in the diagnosis of radicular pain due to lateral canal stenosis in 21 patients is reported. NMR was able to distinguish normal intervertebral discs from degenerate discs, and NMR evidence of reduction of epidural fat was more reliable than radiculography in identifying lateral root entrapment. NMR is an important advance in the investigation of lumbar radiculopathies.

Malignant melanoma of the nasal cavity.

Primary mucosal melanoma of the head and neck is rare and few published cases give proof that the mucosal site is primary. We present a man with malignant melanoma of the nasal cavity which was associated with melanoma-in-situ of the adjacent mucosa, proving that the lesion was primary. He presented with symptoms due to secondary deposits of melanoma in the brain rather than the more usual nose bleeds or blocked nose. The primary site was found when his neurological symptoms were investigated by CT and NMR scans of the head.

Evaluation of the plain abdominal X-ray in the acute abdomen.

The prognostic value of an erect and supine abdominal X-ray was studied prospectively in 97 patients with an acute abdomen. Although 64 (66%) of the radiographs showed an abnormality, the surgical registrar altered his clinical diagnosis on only seven occasions and changed his management on four. A consultant radiologist was the most accurate at reporting the X-rays even without seeing the patient, whilst junior surgical and radiological staff were as accurate as each other. A surgical registrar, however, was more accurate than junior radiologists in making a diagnosis. The investigation was of immediate clinical value in only 4% of the patients, and its use could probably be limited without detriment to patients.

Case report: metastatic renal cell carcinoma presenting as intracerebral haemorrhage.

Cerebral haemorrhage is a well-established, albeit rare, complication of intracranial tumours. An autopsy series of 461 cerebral tumours revealed haemorrhage into only 2%. A case is described of intracerebral haemorrhage which complicated a metastatic renal cell carcinoma. There are four previous cases reported in the literature with this presentation, but this case differs in that the diagnosis was by cerebral angiography and at a site distant to the original haemorrhage.

A description of a low field resistive magnetic resonance imaging system and its application in imaging midline central nervous system pathology.

A commercial low field magnetic resonance imaging (MRI) system installed in the Royal Infirmary, Edinburgh at the end of 1983 has since been used for the clinical investigation of over 1000 patients. This system uses an interlaced saturation recovery and inversion recovery pulse sequence which yields four types of clinical image. AT1 weighted image has been found to be the most sensitive for the detection of pathology. Several examples of pathology with negative X-ray computed tomography examinations including three examples of a syrinx and two cases of tonsillar herniation have been demonstrated using this system. It is suggested that the system could provide a routine clinical service for imaging the central nervous system.

Cranial diabetes insipidus secondary to arrested hydrocephalus.

An unusual case is described linking cranial diabetes insipidus with longstanding arrested hydrocephalus. The latter was demonstrated by computed tomographic (CT) and nuclear magnetic resonance (NMR) scans and cerebrospinal fluid pressure measurements. The increasing use of CT and NMR scans may result in this association of cranial diabetes and hydrocephalus being better defined.