Vertebral metastases and an equivocal bone scan: value of magnetic resonance imaging.

To assess the value of magnetic resonance imaging (MRI) in the investigation of patients with suspected but nonproven vertebral metastases 45 consecutive patients referred in a 6 month period with known primary malignancy and back pain in whom an isotope bone scan was reported as equivocal were studied. All patients had abnormal isotope uptake localized to the spine. Twelve patients were shown to have bony metastases on plain X-ray. In the remainder, where X-rays showed normal or benign appearance, MRI of the spine was offered. Twenty-four patients underwent MRI examination which showed vertebral metastases in 11 cases. Magnetic resonance imaging is shown to be a useful, noninvasive, complementary investigation for evaluation of patients known to have malignant disease and suspected of having vertebral metastases on bone scintigraphy.

Changes in cranial CSF volume during hypercapnia and hypocapnia.

Magnetic resonance imaging was used to measure the effect of inhalation of 7% CO2 and hyperventilation with 60% O2 on human cranial cerebrospinal fluid volume. During CO2 inhalation there was a reduction in the cranial CSF volume ranging from 0.7-23.7 ml (mean 9.36 ml). The degree of reduction in cranial CSF volume was independent of the individual subject's increase in end-expiratory pCO2 or mean arterial blood pressure, in response to hypercapnia. During hyperventilation with high concentration oxygen the cranial CSF volume increased in all subjects (range 0.7-26.7 ml, mean 12.7 ml). The mean changes in cranial CSF volume, induced by hypercapnia and hypocapnia, were very similar to the expected reciprocal changes in cerebral blood volume.

Brain lesions detected by magnetic resonance imaging in mild and severe head injuries.

50 patients were studied by magnetic resonance imaging (MRI) within one week of a head injury. Abnormalities indicating primary brain damage were found in 46 patients, almost twice as many as with computed tomography. Cortical contusions were the most common finding, irrespective of the effect of injury on the level of consciousness. Intracerebral lesions were seen only in patients who had lost consciousness and were present in 29 of 42 patients whose consciousness was still impaired on arrival at hospital. Lesions in the deep white-matter of the cerebral hemispheres were seen in 15 patients; they were significantly more frequent in patients in coma but were also seen in patients who had lost consciousness for no more than 5 min. The findings indicate that lesions in the cerebral hemispheres may be the primary factor in traumatic unconsciousness. MRI studies may also clarify the sequelae of head injuries.