Resistive NMR of intracranial hematomas

Imaging Evaluation of Acute Traumatic Brain Injury

Traumatic brain injury (TBI) is a major cause of morbidity and mortality worldwide. Imaging plays an important role in the evaluation, diagnosis, and triage of patients with TBI. Recent studies suggest that it also helps predict patient outcomes. TBI consists of multiple pathoanatomic entities. This article reviews the current state of TBI imaging including its indications, benefits and limitations of the modalities, imaging protocols, and imaging findings for each of these pathoanatomic entities. Also briefly surveyed are advanced imaging techniques, which include several promising areas of TBI research.

"Nidus sparing sign" on computerized tomography in intracerebral haemorrhage due to a rupture of arteriovenous malformation

The authors investigated the validity of noncontrast computerized tomography (NCCT) to predict the presence of arteriovenous malformations (AVM) as a cause of intracerebral haemorrhage (ICH) in the acute stage. They found a small iso- or slightly hyperdense nodular or tubular defect devoid of haematoma in its periphery on NCCT in 8 of the 13 AVM cases that underwent both NCCT and contrast CT. This CT finding was named "nidus sparing sign" (NSS). This haematoma-free notch was enhanced on contrast infusion and confirmed to correspond to the AVM nidus surgically and pathologically. In one case with negative angiograms, a small AVM was verified histologically within the tissue corresponding to the NSS. The NSS noted on the NCCT could be of great value in case emergency surgery is needed for comatose patients with ICH, particularly lobar ICH, without enough time left to undergo angiography and/or magnetic resonance imaging. Neurosurgeons are able to safely perform an evacuation of the haematoma keeping in mind the possibility of a ruptured AVM and if so, the spatial relationship between the AVM nidus and the haematoma. This might also be a valuable CT sign in deciding whether or not angiography should be undertaken in ICH cases.

Magnetic resonance imaging in acute head injury

Using cardiorespiratory monitoring and support equipment compatible with a low field (0.15 T) system, magnetic resonance imaging (MRI) of patients suffering acute head injuries proved to be both feasible and safe. An abnormality was demonstrated by magnetic resonance imaging in 46 of 50 patients examined within 7 days of head injury using T2 weighted (SE2200/80) and T1 weighted (IR2000/600/40) multislice sequences. IN contrast, computed tomography (CT) demonstrated abnormalities in only 31 of the 50 patients. Intracranial extracerebral space-occupying collections of blood were well shown by magnetic resonance imaging which provided especially clear definition in the posterior fossa, subtemporal and subfrontal regions. Magnetic resonance imaging was more sensitive to cerebral abnormalities associated with traumatic unconsciousness and detected parenchymal lesions both in patients in coma and in those who had lost consciousness for only a few minutes. Lesions seen with MRI but not with CT included non-haemorrhagic contusions and abnormalities thought to reflect shearing injuries of white matter and intracerebral vessels. Magnetic resonance imaging is an effective alternative to CT; the additional information it can provide should be valuable in increasing the understanding of the early effects and late consequences of a head injury.

Magnetic resonance imaging and computerized tomography in relation to the neurobehavioral sequelae of mild and moderate head injuries

Twenty patients admitted for minor or moderate closed-head injury were studied to investigate the relationship between magnetic resonance imaging (MRI) and neurobehavioral sequelae. The MRI scans demonstrated 44 more intracranial lesions than did concurrent computerized tomography (CT) scans in 17 patients (85%); most of these lesions were located in the frontal and temporal regions. Estimates of lesion volume based on MRI were frequently greater than with CT; however, MRI disclosed no additional lesions that required surgical evacuation. Neuropsychological assessment during the initial hospitalization revealed deficits in frontal lobe functioning and memory that were related to the size and localization of the lesions as defined by MRI. Follow-up MRI and neuropsychological testing at 1 month (13 cases) and 3 months (six cases) disclosed marked reduction of lesion size paralleled by improvement in cognition and memory. These findings encourage further investigation of the prognostic utility of MRI for the clinical management and rehabilitation of mild or moderate head injury.

Magnetic resonance imaging in the evaluation of treatment-related central nervous system damage

Neurologic and neuropsychologic treatment related sequelae are increasingly encountered in children with cancer, but conventional means of neurologic investigation are insensitive to the presence and extent of damage. Magnetic resonance imaging (MRI) has shown brain damage not demonstrable by other means of investigation. For this reason, 11 children with cancer and with nontumor-related neurologic dysfunction were studied on a 1.5 Tesla MRI unit. All had concurrent computed tomography (CT). MRI abnormalities were seen in all (100%) patients. In 10 of 11 patients, abnormalities were of greater extent on MRI than on CT. White matter changes were frequently seen on MRI without corresponding CT abnormality. Those patients with the most severe forms of neurologic compromise had the most extensive changes on MRI. Focal neurologic findings correlated well with regions of focal signal change. Milder forms of neurologic compromise occurred in patients with definite, but less extensive, periventricular and/or subcortical change on MRI. MRI is more sensitive than CT in demonstrating treatment-related neurologic damage in children with cancer, and the type of change seen on MRI seems to correlate well with the type and severity of neurologic dysfunction present.

Applications of magnetic resonance imaging in diseases of the pediatric central nervous system

Magnetic resonance imaging (MRI) is rapidly becoming the initial diagnostic step in the evaluation of gross abnormalities involving the brain or spinal cord in the pediatric patient. Control of patient motion and support of vital functions are critical if future utilization of MRI is to progress beyond its current outpatient diagnostic role. Currently, MRI's noninvasiveness, sensitivity and multiplanar graphic depiction of the disease process are supplanting the more traditional diagnostic modalities of CT, metrizamide CT, and myelography.

Orbital magnetic resonance imaging

Magnetic resonance images of the eye and orbit performed with surface coils at 1.5 tesla showed anatomic details superior to those of conventional third- and fourth-generation computed tomography.