Computed tomographic patterns of muscles in neuromuscular diseases.

Computed tomographic (CT) scans of muscle in 35 patients with neuromuscular diseases showed distinct patterns in nerve and muscle diseases. Neural diseases first showed as muscle atrophy, with decreased density in the muscles occurring later in the course of disease. Primary muscle diseases showed early decreased density in the muscles, with atrophy occurring later. The CT scan allows objective assessment of muscle mass and may be used to help select muscles for biopsy.

Cortical blindness after metrizamide myelography. Report of a case and proposed pathophysiologic mechanism.

Metrizamide, a nonionic, water-soluble contrast medium, has been increasingly used for myelography. We saw a patient with cortical blindness, seizure, organic psychosis, and asterixis after undergoing attempted metrizamide myelography via C1-2 puncture. Computed tomography demonstrated early penetrance of metrizamide into the brain parenchyma, most prominently in the occipital lobes. A mechanism of direct metrizamide neurotoxicity was proposed.

Computerized axial tomography in clinical pediatrics.

Computerized axial tomography (CAT), a noninvasive radiologie method, provides a new dimension in screening and diagnosis of intracranial pathology. Evaluation of 725 scans in infants and children demonstrates that CAT may be performed with negligible risk, although sedation and restraint are essential to the successful performance of studies in children under 6 years of age. CAT is the preferred initial diagnostic method in suspected hydrocephalls and is accurate in the detection and precise localization of brain tumors. The management of hydrocephalus and brain tumors has been significantly altered by the availability of CAT. Few invasive neuroradiologic procedures are required and pneumography is especially curtailed. Serial scanning is the best available method of monitoring ventricular alterations in hydrocephalus, tumor size during radiotherapy or chemotherapy, and postoperative recurrence of benign neoplasms. Complex intracranial anomalies are detectable with computerized tomography, but complete definition of pathology often requires angiography and air studies. Limited clinical experience in detecting neonatal intraventricular hemorrhage suggests that CAT will be a valuable tool for futlre investigations of that problem.

Computed cranial tomography and radionuclide cisternography in hydrocephalus.

Computerized Cranial Tomographic scanning has replaced radionuclide cisternography in screening both adult and pediatric patients for hydrocephalus. Nevertheless, cisternography provides indispensable information about the CSF clearance capacity and remains a valuable adjunct to the excellent anatomic detail provided by CCT scans. In patients without emergency symptoms, cisternography provides the best indication as to whether or not diversionary shunting is likely to relieve the patient's symptoms.

Abdominal aortic aneurysms: diagnostic review and new technique.

A new technique of computed tomography (CT) applied to the diagnosis of abdominal aortic aneurysms is described, and the experience in 58 patients is reviewed. In all instances the abdominal aorta was clearly demonstrated, even when wall calcification was absent. A series of 37 patients with abdominal aortic aneurysm underwent evaluation by physical examination, abdominal roentgenograms, and ultrasonic and CT scanning. Measurements of the transverse diameter at the point of maximal dilatation were compared with the measurements made at operation. CT not only confirmed the diagnosis in all patients but the measurements obtained by this technique were the most accurate, correlating extremely well with the true dimensions of the aneurysm. The addition of contrast enhancement to CT scanning allowed clear delineation of the aortic lumen and intraaneurysmal thrombus, not possible with any other method, including ultrasonography. The technique appears useful as a screening procedure and in the differential diagnosis of a tortuous abdominal aorta. Patients with a small aortic dilatation can be followed accurately by scanning.

Patterns of anterior spinal canal involvement by neoplasms and infections.

PURPOSE: To show that retrovertebral extension of neoplastic and infectious disease proceeds in a predictable manner, with the anatomic superstructure determining the shape of the advancing process. METHODS: We examined 58 patients who had neoplastic (n = 44) and infectious (n = 14) processes that caused canal compromise. In total, 140 levels were examined by means of MR imaging only (48 patients), CT only (1 patient), CT plus MR imaging (3 patients), and MR imaging plus CT myelography (6 patients). RESULTS: At 136 levels, the retrovertebral disease process took the shape of a smoothly marginated, bilobulated mass that was broad-based against the posterior surface of the vertebra. Various degrees of mass effect were observed: symmetric on 108 levels and asymmetric on 28 levels; on 4 levels, expansion of the anterior epidural space was unilobar, reflecting unilateral canal invasion. With advanced stages of canal invasion, this bilobulated pattern was maintained but there was a tendency toward detachment of the midline septum (20 levels). CONCLUSION: The observed patterns are determined by the particular anatomy of the anterior epidural space. The shape of the mass is imposed by the posterior longitudinal ligament and by the attached lateral membranes, with the central tether produced by the attached midline septum. The two compartments expand independently.

Sonography of neonatal periventricular leukomalacia: recent experience with a 7.5-MHz scanner.

This study compared the relative efficacy of 5.0- and 7.5-MHz (high-resolution) transducers in the sonographic evaluation of cystic periventricular leukomalacia (PVL). Of 668 premature neonates evaluated by cranial sonography over a 4-year period, 34 were diagnosed as having PVL. Of these 34 neonates, 17 were examined with both 5.0- and 7.5-MHz transducers. Fifty-two neonates with no evidence of PVL also were evaluated by sonography with the two different-frequency transducers to determine the normal appearance of the neonatal brain. Among the neonates with PVL, features of the disease that have not been observed with routine 5.0-MHz transducers were apparent with use of the 7.5-MHz transducer: 7.5-MHz scanning clearly identified small areas of cystic PVL in three (17.6%) of 17 neonates that were not visible using the lower-resolution technique. The higher-resolution scanning also identified widening of the interhemispheric fissure by anechoic cerebrospinal fluid and demonstrated the falx as a distinct structure. The latter two superficial abnormalities were identified in combination with enlargement of the lateral and third ventricles, suggesting that diffuse cerebral atrophy accompanies PVL in most cases. The excellent near-field resolution of 7.5-MHz technology makes it the preferred method for the evaluation of PVL in the preterm neonate.

Cystic periventricular leukomalacia: sonographic and CT findings.

Periventricular leukoencephalopathy (PVL) is a pathologic process that has attracted little attention in neurodiagnosis. It is the second most common acquired central nervous system abnormality in neonates, outranked only by germinal matrix hemorrhage. Autopsy series suggest a 7%-22% incidence, but clinical recognition is poor. The diagnosis usually signals a less favorable neurodevelopmental outcome. Twenty-one cases with PVL and later cavitation (cystic PVL) were reviewed. Sonography was compared with computed tomography (CT) where applicable. In this series 4.8% of all neonates referred from an intensive care nursery developed cystic PVL. Hemorrhagic and nonhemorrhagic forms were observed. Sonography depicted both forms as strong periventricular echoes. Small cysts developed in the subacute phase. CT was unreliable in diagnosing the nonhemorrhagic form of PVL and had a tendency to miss the development of white-matter cysts. Sonography proved to be an excellent method for establishing the initial diagnosis and recognizing late sequelae. Late CT changes consisted of periventricular cysts, irregularity of the ventricular wall, ventricular enlargement, and cerebral atrophy.

CT of the brain in taste and smell dysfunction.

Three hundred fifty-four patients with taste and/or smell disorders were evaluated with computed tomography (CT). The largest group was characterized by head trauma (27%), followed by idiopathic causes (26%), postinfluenza-like hyposmia and hypogeusia (15%), and congenital etiologies (14%). Hyposmia and hypogeusia occurred concomitantly in 21%-45%, the percentage varying according to etiologic subgroup. CT abnormalities were found in 108 (31%) of the 354 patients. The most frequent pathologies were frontal encephalomalacia, subfrontal atrophy in the region of the olfactory bulbs, and anterior temporal lobe atrophy. These changes were found alone or in tandem. Some CT findings suggest common cerebral taste and smell centers and common neural pathways and association centers.

Periventricular leukomalacia in combination with intraventricular hemorrhage: sonographic features and sequelae.

Periventricular leukomalacia (PVL) is well recognized as a relatively uncommon yet particularly serious complication of prematurity. Although the sonographic features of PVL have been described, its association with intraventricular hemorrhage (IVH) has not been emphasized. Reviewing 26 consecutive cases of PVL in neonates of 34 weeks or less gestational age, significant associated hemorrhage was found in six (23%). Small quantities of blood were also noted in most of the other 20 infants. Of the six infants with both significant IVH and PVL, five required ventricular shunt and all had particularly poor clinical outcomes. In the neonates who required surgical intervention, rapid ventricular enlargement was accompanied by extensive periventricular cyst formation. Eventually, the septations within the cysts and frequently even the ependyma of superior/posterior lateral ventricles degenerated. Cysts merged imperceptibly with the ventricles giving an appearance that mimicked severe hydrocephalus. This was termed "pseudoventricle formation," as the large intracerebral cerebrospinal fluid spaces are primarily porencephaly and not enlarged ventricles. Response to shunting was minimal by sonography in all five cases and multiple shunt revisions were required in four. Clinical follow-up in children with significant IVH in combination with PVL has shown severe mental retardation and tetraplegia in all cases.

Potential value of vertebral proton MR spectroscopy in determining bone weakness.

BACKGROUND AND PURPOSE: Increased fat content in vertebrae may indicate bone weakness. Vertebral proton MR spectroscopy ((1)H MRS) quantitatively measures vertebral fat relative to water. Thus, (1)H MRS measurements of percent fat fraction (%FF) and spectral line width (LW) of vertebral bone marrow may differ between subjects with and those without MR imaging evidence of weakened bone. METHODS: We measured %FF and LW in 22 subjects with (15 men and 7 women, aged 26 to 80 years) and 72 control subjects without (33 male and 39 female subjects, aged 15 to 87 years) MR findings of weakened bone, including prominent Schmorl's nodes, endplate depression, vertebral wedging, and vertebral compression fractures. In those with bone weakness, (1)H MRS data were sampled from an intact vertebra, usually L2. Data were analyzed for differences by age and sex. We compared the mean %FF and LW in subjects with and in those without bone weakness by use of Student's t test. RESULTS: The %FF increased linearly with age in the control subjects, ranging from 20.5% in the second and third decades of life to 49.4% in eighth or ninth decades of life. Across all age groups, male control subjects had a higher aggregate %FF than did female control subjects. Male control subjects tended to have a greater LW than did female control subjects, but differences between the sexes within or across age groups were not significant. Contrary to expectations, LW was greatest in the oldest control subjects and lowest among younger control subjects, but there were insufficient data points to make definitive conclusions. Overall, %FF was a relative 45% higher in subjects with weakened bone compared with control subjects (48.8 vs 33.6 [P <.001]). The subjects with evidence of vertebral bone weakness also had a higher overall mean LW (37 vs 29 Hz [P <.002]), but this finding is of uncertain importance. CONCLUSION: The %FF was significantly higher within the L2 vertebral body in 22 subjects with weakened bone compared with the control group, suggesting that it could serve as a measure of bone quality. The LW measurements did not yield meaningful conclusions.

Intracranial hemorrhage in neonates with erythroblastosis fetalis: sonographic and CT findings.

Cranial sonography revealed cerebral hemorrhage in three of seven neonates with erythroblastosis fetalis. Among the three infants with hemorrhage, one was 28 weeks gestational age and experienced germinal matrix hemorrhage with ventricular extension, a finding typical of cerebroventricular hemorrhage in the premature population. The other two infants with intracranial hemorrhage were more gestationally mature, and extensive intraparenchymal cerebral hemorrhages were found at sonography. These hematomas were peripheral in location and one was multifocal. Computed tomography (CT) further revealed hemorrhages in both neonates to be multifocal and in close proximity to the pia-arachnoid. In one case, the hemorrhage appeared to extend centripetally and rupture into the ventricular system. The high incidence, severity, and unusual appearance of intracranial hemorrhages in neonates with erythroblastosis fetalis has not been previously emphasized in the radiologic literature. In severe cases, children with erythroblastosis fetalis should be closely observed for intracranial hemorrhage by either sonography or CT, regardless of gestational age.

Cerebral intraparenchymal hemorrhage in neonates: sonographic appearance.

The real time sonographic findings of five neonates with cerebral intraparenchymal hemorrhage are reported. In each case, areas of markedly increased echogenicity corresponded to the site of hemorrhage. Excellent correlation was found between computed tomography (CT) and sonography. Although the sonographic appearance of intraparenchymal hemorrhage is characteristic, it is difficult to separate blood from other contiguous highly reflective structures in the head, including choroid plexus, bone, and the tentorium. It appears that real time sonography may offer an alternative to CT in the diagnosis of cerebroventricular hemorrhage in neonates.

Ventricular septa in the neonatal age group: diagnosis and considerations of etiology.

Twenty-four patients with ventricular septa are discussed. Seventeen patients had septa acquired during the neonatal period and seven exhibited septations at birth (cogenital septa). Among the acquired septa, there were true intraventricular septa and septa that originated outside the ventricles but later became part of the ventricular system (pseudosepta). Pseudosepta originate in necrotic, cavitating periventricular white matter that, in temporal sequence, becomes ventricularized. Serial use of cranial sonography provided important information about the pathologic mechanisms that govern the development of septa. Intraventricular hemorrhage and infection are the major causes of true intraventricular septa, while periventricular leukomalacia serves as primary cause of pseudosepta. Sonography is the diagnostic method of choice. Septa are associated with a high incidence (62%) of shunt failure.

Thin-section CT of midbrain abnormalities in progressive supranuclear palsy.

Thin-section computed tomographic (CT) scans of 3 and 1.5 mm thickness were obtained using the Philips Tomoscan 310 and General Electric 8800 CT/T scanners in the study of 10 consecutive patients with progressive supranuclear palsy (PSP) and 31 patients with other diseases. Marked midbrain and moderate pontine atrophy, a dilated third ventricle, and enlarged quadrigeminal plate cisterns were observed in all PSP cases. The aqueduct was dilated in several. In six of the PSP cases, there was a striking midbrain abnormality in the form of a low-density area extending from the interpeduncular cistern toward the aqueduct. Thin-section metrizamide-enhanced cisternography of three of the six PSP cases showed that the low-density abnormality was the result of the interpeduncular cistern invaginating the atrophic midbrain.

MR of slow CSF flow in the spine.

PURPOSE: To evaluate a slow-flow MR sequence in normal CSF flow and in CSF flow disturbance in cases of spinal stenosis. METHOD: The method was tested for flow sensitivity and applied to 67 sites of spinal canal compromise. RESULTS: Phantom studies show that flow can be depicted at a velocity of 0.5-1 mm/sec. On clinical images, stagnant CSF is black, flowing CSF is bright. Typically, in high-grade (90%-100%) stenosis, CSF above and below the site of spinal canal compromise (SCC) is black. With intermediate stenosis (50%-89%), CSF above the SCC remains white but becomes black distal to the SCC. Low-grade stenosis shows only localized flow disturbances. CONCLUSION: This easy-to-use sequence can solidify the MR diagnosis of high-grade stenosis when a distinct flow pattern is recognized. Flow patterns for intermediate and low-grade stenosis are less reliable.

A clinical and neuropathologic study of silk suture as an embolic agent for brain arteriovenous malformations.

PURPOSE: To evaluate the safety and efficacy of silk suture as an agent for preoperative embolization of cerebral arteriovenous malformations. METHODS: Clinical and histopathologic results were analyzed in six patients who underwent embolization of cerebral arteriovenous malformations using silk suture in combination with other agents. RESULTS: Three of the patients treated with silk hemorrhaged after embolization, and two of these patients died. Neuropathologic analysis of four patients showed acute perivascular inflammation, sometimes quite severe. CONCLUSIONS: The inflammatory response to silk may explain its effectiveness in producing vascular occlusion. However, a fulminate vasculitis theoretically can predispose to delayed hemorrhage. Other problems with silk include the pressure required to inject the agent and the inability to determine the final site of deposition of the silk. Although other embolic agents may share some of these potential difficulties, we feel that the disadvantages outweigh the advantages of silk as an embolic agent.

The low back pain syndrome. Diagnostic impact of high-resolution computed tomography.

This article focuses on low back pain which is directly related to the spinal axis and its supporting structures (spondylogenic back pain). This type of back pain is particularly prominent in our society, is frequently managed surgically, and has benefited from most advanced diagnostic imaging with computed tomography.

The role of duplex carotid sonography, digital subtraction angiography, and arteriography in the evaluation of transient ischemic attack and the asymptomatic carotid bruit.

This article reviews the uses of arteriography, venous digital subtraction angiography, and duplex carotid sonography in the evaluation of patients with an asymptomatic carotid bruit or carotid system transient ischemic attack. It concludes with a description of the authors' guidelines for their use.

Reliability of left and right indicators in CT scanning of the head. Case report.

A case is described in which incorrect preliminary programming of a computerized tomography (CT) machine caused transposition of the left- and right-side indicators in a CT scan, which led to craniotomy on the normal side. The possible mechanism for this is incorrect pre-scan programming of the CT scanner with respect to patient positioning in the scanner gantry. This error, although unlikely, is still possible with the present generation of CT scanners.