Comparison of cisternal and lumbar CSF examination in leptomeningeal metastasis.

We compared cisternal and lumbar CSF examination in 14 patients suspected of having leptomeningeal metastasis from cancer. Malignant cells were present in 12 patients--in both cisternal and lumbar CSF in nine patients and only in cisternal CSF in three. Cisternal CSF cytologic examination should be considered in patients suspected of having leptomeningeal metastasis if lumbar CSF is nondiagnostic.

Vertebral osteomyelitis and aortic lesions: case report and review.

Coexistence of vertebral osteomyelitis and lesions of the aorta is rare but may be lethal if not diagnosed promptly and treated effectively. We describe a patient who was treated at the Cleveland Clinic Hospital, and we review 69 additional cases reported in the literature. The native aorta was involved in 66 cases; four patients developed infection of prosthetic aortic grafts. The most common aortic lesions associated with vertebral osteomyelitis were mycotic aneurysms, infected aneurysms, and pseudoaneurysms. The wide variety of pathogens involved included salmonellae and other gram-negative bacilli, mycobacteria, gram-positive cocci, and fungi. In some cases infection was polymicrobial. The condition was associated with protean clinical manifestations. Diagnosis was frequently delayed, and mortality was 71%. In some instances surgical procedures at sites of unsuspected aneurysms precipitated life-threatening hemorrhage. Therapy with antimicrobial drugs alone was insufficient. The best results were achieved when specific drug therapy was combined with resection of the infected aorta or aortic graft, thorough debridement, and extraanatomic bypass grafting.

Magnetic resonance of intracranial epidermoids.

The magnetic resonance images of seven patients with biopsy-proven epidermoids were evaluated. The epidermoids were hypointense on T1-weighted images. Intermediate density images revealed the tumors to be heterogeneous in signal intensity consisting of areas of hypo- and isointensity. Signal intensity on T2-weighted images was hyperintense and inhomogeneous in all but one case. CT performed in five patients demonstrated the tumors to be well-defined hypodense lesions without contrast enhancement.

Intracranial chemical-shift artifacts on MR images of the brain: observations and relation to sampling bandwidth.

The purpose of this study was to evaluate the presence of chemical-shift artifacts on cranial MR and to illustrate the interrelationship among chemical-shift artifacts, variable acquisition parameters, and field strength. Measurements of chemical-shift artifacts were performed on scans obtained from a volunteer imaged in a 1.5-T General Electric system at bandwidths of 8, 16, and 32 kHz, using a 24-cm field of view and an 8-kHz bandwidth with a 48-cm field of view. Chemical-shift displacements at 8 kHz were 6.6 and 14.2 mm at the respective fields of view. Retrospective review was also performed in 77 cases of cranial MR performed on a 1.4-T Technicare unit for the presence and source of chemical-shift artifact on spin-density and T2-weighted images. Most data reviewed showed no significant interference of chemical-shift artifacts on cranial images. An artifactual subdural fluid collection was a common artifact (n = 30/77). When present, this was due to shift of fat signal from subcutaneous tissues onto the brain in patients younger than 10 years old (n = 4/10) and correlated with the distance between brain and subcutaneous fat of less than the linear value of the chemical shift. When this artifact was present in adults (n = 25/67), it was due to shift of the medullary fat signal across the inner table of the skull. The latter also occurred in one child under 10. Apparent location shifts, consistent with the displacement expected from the chemical-shift artifact, were noted in five of five cases of intracranial lipoma. In one of these, the chemical-shift artifact disguised the presence of a large associated vessel. The method of calculating the linear displacement of chemical-shift artifact is reviewed, and the interrelationship of machine parameters and chemical-shift artifact is illustrated. Chemical-shift artifact increases proportionally with field strength and field of view. Increasing the bandwidth to decrease chemical-shift artifact has a resultant penalty in signal to noise but allows a lower time to echo. A lower time to echo can also be accomplished without increasing the bandwidth if asymmetric sampling is used. Awareness of the relationships among chemical-shift artifacts, acquisition parameters, and field strengths can result in a more tailored examination when the chemical-shift artifact is going to be a significant factor. In addition, interpreter error can be avoided by awareness of these relationships when reviewing images from outside institutions.

The Sturge-Weber syndrome: comparison of MR and CT characteristics.

Four patients with Sturge-Weber syndrome were evaluated with CT and MR. MR demonstrated the characteristic features of the disease: cerebral atrophy (four patients), ipsilateral bone and sinus hypertrophy (three), ocular findings (one), intracranial calcification (four), prominent deep venous system (three), and enlarged choroid plexus (two). CT demonstrated the following: cerebral atrophy (four), ipsilateral bone and sinus hypertrophy (three), calcification (four), gyral enhancement (two), prominent deep venous system (two), and enlarged choroid plexuses (three). The features of Sturge-Weber syndrome were visualized equally well with MR and CT with the exception of intracranial calcification. Conventional spin-echo MR revealed fewer calcifications, and those visualized appeared smaller than with CT. Gradient-echo acquisition sequences were more effective in the detection of intracranial calcification.

Three-dimensional surface rendering of nasal anatomy from computed tomographic data.

This article investigates the potential of using three-dimensional surface-rendered computed tomographic reconstructions for demonstrating normal and pathologic intranasal anatomy. Three-dimensional surface renderings of the intranasal structures were generated in 38 patients from coronal high-resolution computed tomographic images. Because of the complex anatomy, three-dimensional images were believed to be useful for surgical planning. There may be a correlation between the appearance of the uncinate process and severity of inflammatory sinus disease.

Occult radiologic changes in the skull and jaw in familial adenomatous polyposis coli.

It has been suggested that radiology of the skull and jaw in familial polyposis coli may be a useful marker in up to 90 percent of cases. These x-rays were reviewed independently by a dental surgeon and a neuroradiologist in 51 patients. Only seven patients (14 percent) had significant lesion seen in the context of screening. Each of these patients also had other extracolonic manifestations of familial polyposis coli. The Cleveland Clinic Foundation experience with radiology of the jaw and skull is that it is not a useful screening tool.

The significance of asymmetry of the foramen of Vesalius.

The foramen of Vesalius is a small, variable but consistently symmetrical structure located anteromedial to the foramen ovale and lateral to the foramen rotundum and vidian canal. It transmits an emissary vein through which the cavernous sinus and pterygoid plexus communicate. Fifty high-resolution CT scans of the skull base and two three-dimensional (Cemax) reconstructions were reviewed to determine criteria for defining the normal appearance of the foramen of Vesalius. Three normal types were classified: (1) a well-formed foramen, 1-2 mm in size (n = 32); (2) lack of visualization of the foramen (n = 11); and (3) partial assimilation of the foramen with the foramen ovale (n = 7). The foramen was remarkably symmetric in a large number of cases (n = 48). Asymmetry signified abnormality in four of the six cases. Abnormal causes of asymmetry included invasion by nasopharyngeal melanoma, angiofibroma, carotid cavernous fistula with drainage through the emissary vein, and neurofibromatosis. Thus, for these usually symmetric foramina of Vesalius, asymmetry is more likely the result of a pathologic process than a normal variant.

Vertebral osteomyelitis presenting as spinal compression fracture. Six patients with underlying osteoporosis.

Six patients with osteoporosis had vertebral osteomyelitis (VO) with infection of a single vertebra that presented with a collapsed vertebral body, thought to be a simple compression fracture. The resulting delay in correctly diagnosing VO was associated with disabling sequelae in a high proportion of cases. This distinctive presentation accounted for 13% of all hospitalized patients with VO and 2.4% of inpatients with osteoporotic compression fractures during the last five years; it may be more common than suggested by the paucity of published cases. In patients with osteoporosis and vertebral compression fractures, osteomyelitis should be considered when there is severe back pain, persistent unexplained fever, unexplained elevation of the erythrocyte sedimentation rate, or bacteremia without an obvious extravertebral focus of infection, particularly if the patient is immunocompromised. Early biopsy and culture of the collapsed vertebral body will facilitate diagnosis and therapy.

Cranial postoperative site: MR imaging appearance.

The ability to diagnose adverse postcraniotomy or postcraniectomy events is essential for proper postoperative care. The importance of identifying postoperative changes on CT has previously been shown. The purpose of this study is to assess the normal and abnormal MR changes that may be seen in the postcraniotomy/postcraniectomy period. The postoperative MR, CT, and medical records of 41 postcraniotomy patients and 26 postcraniectomy patients were reviewed. Reasons for choosing craniectomy over craniotomy included decompression, infected flap, bony involvement by tumor, and posttraumatic skull. In general, the postoperative normal anatomy was better seen with MR. Postoperative events included hemorrhage (two), infection (five), cyst formation (10), and recurrent tumor (five). In general, MR was found to be more useful than CT for the detection of hemorrhage and infection after craniotomy or craniectomy and for the proper localization of postoperative cysts. MR proved to be a useful method for following postoperative sites in the skull.

The preoperative venogram in planning extended craniectomies.

A technique of extended craniectomy sometimes allows removal of large central or transtentorial mass lesions at a single operative sitting because it affords better exposure and control of normal structures. While seeking to avoid multiple craniotomies, this method requires permanent ligation of the transverse venous sinus. Unless there is adequate collateral venous drainage from the ipsilateral hemisphere, the patient is at risk for venous infarction in the post-craniectomy period. The purpose of this study is to propose a method of establishing the presence of collateral venous drainage preoperatively. Each carotid artery is injected with the head in a neutral position and with the head turned to the side ipsilateral to the carotid artery injection in an attempt to divert the venous flow. Fifty patients were examined using this method; seven were being evaluated for possible craniectomies. The technique identified nine patients with potential venous collaterals (20%). They would otherwise have been considered nonoperable: two of the six patients eventually operated upon (33%) fell into this category. In general, the operative procedure may be safe more often on the left than the right (45%) vs (20%). Particular attention must be given to the pattern of venous drainage from the posterior temporal lobe to avoid isolation of the venous drainage from this area.

Magnetic resonance imaging (1.5 tesla) in patients with intractable focal seizures.

Magnetic resonance (MR) (1.5 tesla) studies were performed in ten patients with temporal lobe epilepsy and two with temporofrontal epilepsy. Two patients with temporal lobe epilepsy and one with temporofrontal epilepsy exhibited areas of increased signal intensity on T2-weighted images in the mesiobasal portion of the temporal lobe shown by electroencephalography to be the epileptogenic focus; no analogous abnormalities had been found in these patients on computed tomographic scans. Pathologic studies have not revealed a specific ultrastructural correlate for the MR findings in this group of patients. We found MR to be a useful, noninvasive diagnostic adjunct in the presurgical assessment of some patients with temporal lobe epilepsy. Where abnormalities were found, they corresponded with the epileptogenic focus as defined by electroencephalography.

Cervical myelopathy: a comparison of magnetic resonance and myelography.

Fifty-seven patients with a strong clinical suspicion of cervical myelopathy were studied with body coil magnetic resonance (MR) and conventional myelography or CT myelography. Eight patients were believed to have normal studies with both modalities. There were six patients with syringomyelia; four with an intramedullary tumor; one with an arteriovenous malformation; 19 with cervical spondylosis at multiple levels; eight with cervical spondylosis at a single level; four with extensive rheumatoid arthritis; four with extradural neoplasm; two with trauma; and one patient with an epidural abscess. In this study, body coil MR was the superior examination for the evaluation of an intramedullary process. It was as diagnostic as myelography in one case of an extramedullary intradural lesion. In patients with extradural disease, body coil MR was the superior study in 45%, equivalent to myelography in 37%, and, although still diagnostic, inferior to myelography in 17%. In 8% of the cases, body coil MR was at best equivocal, whereas myelography was diagnostic. It appears that in technically adequate studies, MR is at least equivalent to myelography in its ability to delineate disease. A superior MR study provides a better appraisal of the size and character of the spinal cord as well as the degree of both anterior and posterior defects on the subarachnoid space and neural structures. In addition, MR is as good as conventional myelography for the identification of extrinsic cervical cord lesions producing cervical myelopathy. Finally, an additional small group of 30 patients were studied with a prototype surface coil to determine its advantages relative to body coil imaging. Each patient had correlative myelography. As with body coil MR, imaging with the surface coil was believed to be more informative than conventional myelography in four patients with intramedullary lesions. The remaining 26 patients suffered from cervical spondylosis. Surface coil MR was believed to be more informative than myelography in six cases (23%), equivalent to myelography in 19 (73%), and less diagnostic than myelography in one (4%). The improved spatial resolution with the use of the surface coil was believed to increase the accuracy of MR.

Magnetic resonance with marked T2-weighted images: improved demonstration of brain lesions, tumor, and edema.

The object of this study was to determine the sensitivity of magnetic resonance (MR) for imaging intracranial lesions with heavily T2-weighted images compared with that of computed tomographic (CT) and T1-weighted images. Fifty-five patients with known intracranial pathology consisting of primary neurogenic tumors, brain infarcts, demyelinating disease, and metastases were studied by MR and CT. Patients were studied with either 0.6 or 1.5 T systems with T1- and T2-weighted radiofrequency pulse sequences. The heavily T2-weighted images were found to be superior to the T1-weighted images in terms of sensitivity, with 168 lesions found versus 86 by CT and 104 by T1-weighted imaging.

Vertebral osteomyelitis: assessment using MR.

Thirty-seven patients who were clinically suspected of having vertebral osteomyelitis were prospectively evaluated with magnetic resonance (MR), radiography, and radionuclide studies. These findings were correlated with the final clinical, microbiologic, or histologic diagnoses. Based on the results of these latter studies, 23 patients were believed to have osteomyelitis. MR examinations consisted of at least a sagittal image (TE = 30 msec, TR = 0.5 sec) and an image obtained at TE = 120 msec, TR = 2-3 sec. All patients underwent radiographic and MR examinations, 36 underwent technetium 99m-HDP bone scanning, and 20 patients underwent gallium 67 scanning. Nineteen patients underwent both bone and gallium scanning. The imaging studies were reviewed independently by investigators blinded to the final diagnoses. MR had a sensitivity of 96%, specificity of 92%, and accuracy of 94%. Combined gallium and bone scan studies (19 cases) had a sensitivity of 90%, specificity of 100%, and accuracy of 94%. Bone scans alone had a sensitivity of 90%, specificity of 78%, and accuracy of 86%. Plain radiographs had a sensitivity of 82%, specificity of 57%, and accuracy of 73%. The MR appearance of vertebral osteomyelitis in this study was characteristic, and MR was as accurate and sensitive as radionuclide scanning in the detection of osteomyelitis.

The intranuclear cleft of the intervertebral disk: magnetic resonance imaging.

Three cadaver spines, 40 patients who were symptomatic for lumbar disk disease, and ten healthy subjects were examined by MR. T2 weighted spin echo images were used to evaluate the character of an intranuclear cleft. This cleft appears identical to annular tissue both on T2 weighted images and histologically. A 120 msec TE, 3 sec TR image was used to delimit the normal nucleus pulposus from the annulus. The incidence and age distribution of the cleft were calculated. An intranuclear cleft was present in all normal disks in both control and symptomatic subjects who were 30 years of age and older. If present in one disk, it was also present in 94% of the other disks in the same subject. This cleft represents a normal anatomic structure and appears to be a constant feature in subjects 30 years of age or older. Its absence, in the presence of an increased signal intensity within the disk, suggests a pathological process with a long T2 value, such as inflammation.

Nuclear magnetic resonance of the spine: clinical potential and limitation.

Magnetic resonance can visualize the vertebral bodies, discs, neural structures, cerebrospinal fluid (CSF), neural foramina, and extradural structures in the sagittal, axial, and coronal planes. The normal nucleus pulposus can be differentiated from the anulus and changes associated with degeneration. Infection, trauma, and neoplastic conditions can be identified. The signal intensity of the CSF relative to extradural and neural structures can be increased to provide evaluation of the size and configuration of the contents of the thecal sac without the use of an intrathecal contrast medium. Impingement by disc, tumors, fracture segments, and expansile masses can then be accurately evaluated. It is the most accurate modality for the evaluation of the foramen magnum, Chiari malformation, syringomyelia, infection, and degeneration of intervertebral discs. It can identify paravertebral soft tissue and bony changes when plain films and computed tomographic (CT) studies are negative or equivocal. Not only can lesions be localized, but significant information regarding the nature of the process can be obtained. Using variations of the spin-echo technique with appropriate T1 and T2-weighted images, magnetic resonance can produce tissue contrast distinctions not possible with CT scans or conventional angiography.

Magnetic resonance imaging of intervertebral disk disease. Clinical and pulse sequence considerations.

Sixty-five patients were examined with magnetic resonance imaging (MR) to determine what combination of operator-selectable controls would result in a thorough examination of the intervertebral disks. There were 20 normal subjects, 8 with degenerative lumbar disk disease, 27 with both degeneration and herniation, 5 with stenosis of the spinal canal, and 5 with disk space infection. T2 was significantly longer in the normal nucleus pulposus than in the degenerated disk. Based on plots of in vivo signal intensity vs. repetition time (TR) for various echo times (TE), a sagittal 30-msec. TE and a 0.25-sec. TR were used for anatomical delineation and rapid localization, while sagittal and/or axial 120-msec. TE/3-sec. TR images were used to evaluate the cerebrospinal fluid and disk. Comparison with radiographs, high-resolution CT scans, and myelograms showed that MR was the most sensitive for identification of degeneration and disk space infection, separating the normal nucleus pulposus from the annulus and degenerated disk. Herniation, stenosis of the canal, and scarring can be identified as accurately with MR as with CT or myelography.

Magnetic resonance imaging of the cervical spine: technical and clinical observations.

Seventy-two patients were examined to determine the clinical potential for magnetic resonance imaging (MRI) of the spine. MRI using different pulse sequences was compared with plain radiography, high-resolution computed tomography, and myelography. There were 35 normal patients; pathologic conditions studied included canal stenosis, herniated disk, metastatic tumor, neurofibroma, trauma, Chiari malformation, syringomyelia, arteriovenous malformation, and rheumatoid arthritis. MRI provided sharply defined anatomic delineation and tissue characterization. It was diagnostic in syringomyelia and Chiari malformation and was useful in the evaluation of trauma and spinal canal block from any cause. MRI was sensitive to degenerative disk disease and infection. The spin-echo technique, with three pulse sequence variations, seems very promising. A short echo time (TE) produces the best signal-to-noise ratio and spatial resolution. Lengthening the TE enhances differentiation of various tissues by their signal intensity, while the combined increase of TE and recovery time (TR) produces selective enhancement of the cerebrospinal fluid signal intensity.

Nuclear magnetic resonance imaging of the spine.

Forty subjects were examined to determine the accuracy and clinical usefulness of nuclear magnetic resonance (NMR) examination of the spine. The NMR images were compared with plain radiographs, high-resolution computed tomograms, and myelograms. The study included 15 patients with normal spinal cord anatomy and 25 patients whose pathological conditions included canal stenosis, herniated discs, metastatic tumors, primary cord tumor, trauma, Chiari malformations, syringomyelia, and developmental disorders. Saturation recovery images were best in differentiating between soft tissue and cerebrospinal fluid. NMR was excellent for the evaluation of the foramen magnum region and is presently the modality of choice for the diagnosis of syringomyelia and Chiari malformation. NMR was accurate in diagnosing spinal cord trauma and spinal canal block. The normal disc was seen, but with rare exceptions bulging of the annulus and herniation of the nucleus pulposus were not visualized.