Distraction rod stabilization in the treatment of metastatic carcinoma

Stabilization of the spinal column with Harrington distraction rods and acrylic fusion was the primary form of treatment in a select group of patients with metastatic carcinoma of the spinal column. Clinical criteria included patients in poor general medical condition with intractable pain originating from metastatic tumor involvement in the ventral components of the thoracic or upper lumbar spinal column and minimal evidence or absence of spinal cord compression. After stabilization, pain relief was almost total and sustained, and neurological status generally remained unchanged from preoperative findings without any evidence of improvement of preexisting abnormalities or occasions of rapid neurological deterioration. This form of spinal stabilization may offer significant relief of debilitating pain, lessen the risk of pathological fracture-dislocation of the thoracic or upper lumbar vertebral column, and reduction in the local compressive effects on the spinal cord caused by ventrally situated metastatic tumor.

Computed tomography of the heart: initial experience

Computed tomography (CT) provides non-invasive diagnosis of cardiac lesions by direct demonstration of the myocardium and the individual cavities of the heart. The potential role of CT scanning in the detection and quantitation of acute myocardial infarction has been previously investigated in experimental animals. Initial experience in assessing 10 patients admitted with recent infarction on biochemical and electrocardiographic evidence is reported. Intravenous infusion of iodinated contrast agents produced contrast enhancement either of the rim or diffusely through the myocardium in the area of infarct, as sited electrocardiographically. Patients with coronary artery bypass grafts and hypertrophic cardiomyopathy have also been studied by this method. Cardiac CT with intravenous administration of contrast may have an important role in the future in assessment and follow-up of ischaemic heart disease.

Clinical NMR imaging of the brain in children: normal and neurologic disease

The results of initial clinical nuclear magnetic resonance imaging of the brain in eight normal and 52 children with a wide variety of neurologic diseases were reviewed. The high level of gray-white matter contrast available with inversion-recovery sequences provided a basis for visualizing normal myelination as well as delays or deficits in this process. The appearances seen in cases of parenchymal hemorrhage, cerebral infarction, and porencephalic cysts are described. Ventricular enlargement was readily identified and marginal edema was demonstrated with spin-echo sequences. Abnormalities were seen in cerebral palsy, congenital malformations, Hallervorden-Spatz disease, aminoaciduria, and meningitis. Space-occupying lesions were identified by virtue of their increased relaxation times and mass effects. Nuclear magnetic resonance imaging has considerable potential in pediatric neuroradiologic practice, in some conditions supplying information not available by computed tomography or sonography.

Nuclear magnetic resonance imaging of posterior fossa tumors

The results of nuclear magnetic resonance (NMR) examinations in 26 patients with histologic (15 cases) or clinical (11 cases) diagnoses of tumors within the posterior fossa were reviewed and compared with x-ray computed tomography (CT). Most tumors displayed an increase in T1 and T2 relative to brain. All seven benign tumors were seen with both CT and NMR, although one of these cases initially was misdiagnosed on the basis of the CT findings. The extent of these tumors was equally well shown with CT and NMR in three cases but was demonstrated better by NMR in four. Calcification was seen with CT but not with NMR in two of these patients. All 19 malignant tumors were demonstrated with NMR. Two of these were not seen with CT. In 12 patients minimal changes consisting of a poorly defined low-attenuation are or minor displacement of the fourth ventricle were noted with CT, although much more extensive changes were seen with NMR. In three patients the changes were equally well shown with both techniques. In the remaining two cases, the extent of the tumor was defined more accurately with contrast-enhanced CT, where the margin between tumor and surrounding edema was better seen than with NMR. Mass effects were better demonstrated with NMR in 13 patients and equally well shown in six. Bony erosion was better demonstrated with CT in two cases. Hydrocephalus with periventricular edema was seen in five patients; in each it was more clearly demonstrated with NMR. The NMR diagnosis of tumors is discussed and relevant new developments are summarized.

Nuclear magnetic resonance imaging of the heart. Current status and future prospects

The basic principles and current status of proton nuclear magnetic resonance imaging are outlined. Nuclear magnetic resonance images of the heart have improved in quality with advances in technique and better gating but clinical experience remains very limited. Myocardial infarction has been shown in animals and man, and plaques of atheroma have been seen with nuclear magnetic resonance flow studies. Further improvements in image quality, faster examination times, 23Na imaging, and the use of paramagnetic contrast agents are advances that are anticipated in the near future.

Nuclear magnetic resonance (NMR) imaging of the brain in systemic lupus erythematosus

Nuclear magnetic resonance (NMR) and X-ray computed tomographic (CT) imaging of the brain were performed on nine patients with clinical evidence of cerebral involvement by systemic lupus erythematosus (SLE). Focal lesions were demonstrated in eight patients by NMR and in six by CT. The examinations with both techniques were negative in one patient and showed essentially identical pathological conditions in three patients. In three patients NMR demonstrated more numerous lesions than CT. All lesions seen on CT were also seen on NMR, mostly with greater clarity and extent. In view of the limited number of patients, this study is preliminary, but it appears that NMR demonstrates more accurately the degree of brain involvement in SLE than CT.

NMR anatomy of the brain using inversion-recovery sequences

The use of NMR inversion-recovery (IR) sequences to demonstrate brain anatomy is illustrated. The high level of grey-white matter contrast is of value in localising anatomical structures and demonstrating myelination during childhood. While the resemblance of IR scans to gross anatomical sections in different planes is close, it is limited by the spatial resolution of the NMR scanner, artefacts and partial volume effects.

Nuclear magnetic resonance (NMR) imaging in white matter disease of the brain using spin-echo sequences

Attention is drawn to the use of nuclear magnetic resonance (NMR) spin-echo sequences in the recognition of white matter disease of the brain. In 5 patients with multiple sclerosis, 8 lesions were seen with postcontrast x-ray computed tomography (CT) (37.5 g of iodine), 33 with inversion-recovery (IR) scans, and 47 with spin-echo (SE) scans. Partial volume effects were less of a diagnostic difficulty with SE scans than with IR scans. Extensive areas of abnormal white matter were seen with CT, IR, and SE scans in a patient with leucodystrophy associated with congenital muscular dystrophy. In a patient with adrenoleucodystrophy focal lesions were seen with CT, IR, and SE scans. In addition, loss of gray-white matter contrast was seen in both occipital lobes with IR scans. Extensive areas of white matter involvement were also seen in a case of Binswangers disease.

Nuclear magnetic resonance imaging of the posterior fossa: 50 cases

Fifty patients with clinical diagnoses of disease within the posterior fossa were examined with a nuclear magnetic resonance (NMR) scanner and the results were compared with X-ray computed tomography (CT). A variety of NMR pulse sequences reflecting proton density, T1, T2 and blood flow were used and imaging was performed in transverse coronal and sagittal planes. In many cases NMR provided diagnostic information unavailable from CT scans. This included recognition of lesions not seen with CT in infarction and multiple sclerosis, as well as more precise definition of mass effects, oedema and anatomical relationships in other diseases. Extrinsic and intrinsic tumours were readily distinguished, as were brain-stem and cerebellar tumours. Arnold-Chiari malformations were demonstrated with sagittal scans and cerebellar atrophy was identified. A patient treated with radiotherapy displayed more extensive changes in the surrounding brain with NMR than with CT. Evidence of occlusion or reduced flow was found in two cases with vertebro-basilar disease. Occlusion of the internal carotid artery was also demonstrated. Computed tomography was superior to NMR in demonstrating calcification and bone erosion. In four of 14 tumours studied, contrast-enhanced CT demonstrated the margin between tumour and surrounding oedema or brain better than NMR. Nuclear magnetic resonance imaging is a versatile, non-invasive technique capable of demonstrating a wide spectrum of disease within the posterior fossa.

Nuclear magnetic resonance (NMR) imaging in Wilson disease

Nuclear magnetic resonance (NMR) scans of the head and liver were obtained in 13 patients with Wilson disease, and the results were compared with computed tomography (CT). Twelve age and sex matched normal controls were also scanned with NMR. The subjects were scanned using repeated free induction decay (RFID), inversion-recovery (IR), and spin-echo (SE) sequences. The IR scans of the brain provided excellent anatomical localisation while SE scans highlighted pathological areas. Within the brain, NMR demonstrated abnormalities in two patients with normal CT scans. More extensive involvement was shown with NMR in three additional cases. In the liver, NMR and CT showed similar abnormalities of morphology. T1 values were within the normal range in all cases, including three patients with high liver copper levels at the time of NMR examination.

NMR imaging in the diagnosis and management of intracranial angiomas

Fourteen intracranial angiomas were clearly visualized and diagnosed with certainty on fast saturation-recovery images, which highlight blood vessels without the use of contrast media, and on steady-state free-precession images, in which the moving blood leads to removal of signal. Performed as the initial investigation, nuclear magnetic resonance obviates angiography when the site and extent of the angioma would preclude operation, and in other cases provides useful anatomic information complementing the angiogram. When clinical presentation follows hemorrhage the size and position of the associated hematoma can be reliably assessed.

Extracerebral collections: recognition by NMR imaging

After head injury, nuclear magnetic resonance (NMR) scanning is, like computed tomography (CT), an effective method of distinguishing between intracerebral and extracerebral lesions. The location and shape of extracerebral collections are excellently displayed using the multiplanar facility of NMR. There are good grounds for believing that the problem of the isodense subdural hematoma encountered in CT scanning can almost certainly be overcome by the use of NMR imaging.

The role of NMR imaging in the diagnosis and management of acoustic neuroma

Nuclear magnetic resonance (NMR) scans of 15 patients with acoustic neuroma are compared with the results of computed tomography (CT). The absence of signal from bone has meant that the images are unaffected by artifacts and that small intracanalicular tumors can be visualized. The multiplanar facility of NMR is emphasized as this allows precise assessment of both tumor volume and its relationship to the ventricular system, brainstem, and tentorial hiatus. The different appearances produced by alternative scan sequences are illustrated and the possibility of predicting the physical constitution from scan appearances is discussed.

Nuclear magnetic resonance imaging of the brain in children

A preliminary study of nuclear magnetic resonance imaging of the brains of four normal children (36 weeks' postmenstrual age to 5 years) showed long T(1) areas in the periventricular region of the neonate as well as evidence of progressive myelinisation with increasing age. Study of 18 patients of 40 weeks' postmenstrual age to 4 years showed an apparent deficit in myelinisation in an infant with probable rubella embryopathy and another with ventricular dilatation of unknown cause. Abnormal scans were obtained in an infant with congenital muscular dystrophy, and abnormalities were visualised at the lateral ventricular margins in a case of acute hydrocephalus after shunt blockage. Periventricular regions of increased T(2) were seen in a term infant aged 4 days after severe birth asphyxia and convulsions.Nuclear magnetic resonance imaging appears to provide a unique demonstration of myelinisation in vivo and shows changes in pathological processes of importance in paediatric practice.

NMR imaging of the brain

The basic features of an NMR imaging system are outlined and three pulse sequences which produce images with varying dependence on proton density T1 and T2 are described. The first of these sequences, Repeated Free Induction Decay produces images which demonstrate changes in proton density as well as flow effects. The second sequence, Inversion-recovery, produces images which are dependent on T1 and show a high level of grey, white matter contrast giving considerable anatomical detail. In addition pathological processes such as infarction, haemorrhages, demyelination and malignancy, produce changes in T1 enabling lesions to be localised. The third sequence, Spin-echo, produces images which are dependent on T2. These show very little grey, white matter contrast but demonstrate acute and space occupying lesions as well as cerebral oedema. The high level of grey, white matter contrast, lack of bone artefact, variety of sequences, capacity for multiplanar imaging, sensitivity to pathological change and lack of known hazard make NMR an important addition to existing techniques of neurological diagnosis.

Clinical NMR imaging of the brain: 140 cases

Cranial nuclear magnetic resonance (NMR) scans were performed on 13 healthy volunteers and 140 patients with a broad spectrum of neurologic disease and compared with x-ray computed tomography (CT) scans. The NMR scans included a variety of sequences reflecting proton density, blood flow, T1, and T2 as well as transverse, sagittal, and coronal images. White matter, gray matter, and cerebrospinal fluid were clearly distinguished in the normal brain with inversion-recovery (IR) sequences, and normal progressive myelination was demonstrated in infants and children. Acute hemorrhages displayed short T1 values, but other pathologic processes such as infarction, infection, demyelination, edema, and malignancy were associated with long T1 values. Cysts had very long T1 values (about that of cerebrospinal fluid). Spin-echo (SE) sequences showed increased values of T2 in a variety of conditions and highlighted lesions against the relatively featureless background of the remaining brain. With inversion-recovery scans, different stages of infarction were recognized in the hemispheres. NMR was more useful than CT in demonstrating brainstem infarction. The white matter lesions in demyelinating diseases were well demonstrated with NMR scans. Many more lesions were observed in multiple sclerosis with NMR than with CT. Benign tumors were well seen and usually had shorter T1 values than malignant tumors. Mass effects from tumors were generally better demonstrated with NMR than with CT, including more subtle mass effects such as displacement of the external capsule. Abnormalities were seen in diseases of the basal ganglia, including marked atrophy of the head of the caudate nucleus in Huntington chorea. Advantages of NMR imaging include the high level of gray-white matter contrast, lack of bone artifact, variety of possible sequences, transverse, sagittal, and coronal imaging, sensitivity to pathologic change, and lack of known hazard. Disadvantages include lack of bone detail, limited spatial resolution, lack of contrast agents, and cost. Promising directions for future clinical research include developmental neurology, tissue characterization with T1 and T2, assessment of blood flow, and the development of contrast agents. Much more detailed evaluation will be required, but NMR seems to be a potentially important addition to existing techniques of neurologic diagnosis.

NMR imaging of the brain using spin-echo sequences

Eight normal volunteers and 32 patients with a variety of neurological disease were studied with a nuclear magnetic resonance (NMR) scanner using repeated free induction decay (RFID), inversion-recovery (IR) and spin-echo (SE) sequences. The results were compared with X-ray computed tomography (CT). RFID sequences which produce images that reflect changes in proton density displayed very little grey-white matter contrast and relatively small changes in disease. IR sequences which produce images that are dependent on T1 showed a high level of grey-white matter contrast and demonstrated changes in a variety of pathological processes. Although SE scans, which have a strong T2 dependence, had shown no abnormality in previous studies of patients with neurological disease, sequences of this type with longer values of tau displayed abnormalities in cerebral infarction, haemorrhage, herpes encephalitis, multiple sclerosis, cerebral oedema, hydrocephalus, tumours and Wilson's disease. All of these conditions were associated with an increase in T2. Abnormalities were demonstrated in cases of multiple sclerosis and brainstem infarction with NMR scans where no abnormality was seen with CT. More extensive changes were seen with NMR in cases of hemisphere infarction, systemic lupus erythematosis, herpes encephalitis, hydrocephalus (periventricular oedema) and Sturge-Weber disease. The margin between malignant tumour and surrounding oedema was better defined with contrast enhanced CT in four of eight malignant tumours, equally well defined in one, and better defined with NMR in three cases. NMR spin-echo sequences provide a sensitive technique for detecting abnormalities in a variety of neurological disease.

Nuclear magnetic resonance imaging of the liver: initial experience

Nuclear magnetic resonance (NMR) scans of the liver were obtained in 12 normal volunteers and 32 patients using a whole-body machine developed by Thorn-EMI Ltd., and the results were compared with x-ray computed tomography (CT). Two types of NMR scan, saturation-recovery and inversion-recovery, were performed in order to obtain values for the spin-lattice relaxation time, T1. Although the saturation-recovery scans show little soft-tissue detail, the inversion-recovery scans demonstrated the interlobar fissure, hepatic veins, portal veins, bile ducts, and gallbladder. In comparison with CT (Siemens Somatom 2), both types of NMR scan showed some blurring due to respiratory movement but much less linear artifact across the liver from the air-fluid interface in the stomach. Focal disease within the liver was demonstrated by both CT and NMR, although an area of focal atrophy and another of hepatic infarction were only recognized with NMR. In diffuse disease the pattern varied. In steatosis CT was virtually diagnostic, while NMR showed no specific features. In hemochromatosis, hepatitis, eight cases of cirrhosis, and one of Wilson disease, both techniques showed abnormalities of varying specificity. In two cases of cirrhosis and one of primary biliary cirrhosis, only the NMR scan was abnormal. Nuclear magnetic resonance images are now sufficiently anatomically detailed to permit serious comparisons with technically advanced computed tomography. The information revealed is fundamentally different and can be expected to have some diagnostic utility.