Intraocular tumors: evaluation with MR imaging.

Sixty-seven ocular tumors were studied with magnetic resonance (MR) imaging and computed tomography (CT). These tumors included primary uveal melanoma (n = 55), circumscribed choroidal hemangioma (n = 3), diffuse choroidal hemangioma (n = 1), retinal capillary hemangioma (n = 1), medulloepithelioma (n = 1), choroidal nevus (n = 1), retinoblastoma (n = 1), and choroidal metastases (n = 4). MR imaging demonstrated all these lesions, while CT demonstrated 88%. Associated retinal detachment was more easily distinguished from the neoplasms with MR imaging. Extrascleral extension of melanoma and hemorrhagic cystic necrosis within the melanoma were clearly demonstrated with MR imaging, but not with CT. Ninety-three percent of melanomas were markedly hyperintense, compared with the intensity of the vitreous body, on T1-weighted images and hypointense on T2-weighted images. All metastatic lesions were isointense on T1-weighted images and hypointense on T2-weighted images. The circumscribed choroidal hemangiomas were hyperintense on T1-weighted images and isointense on T2-weighted images. MR imaging is superior to CT in detection of intraocular tumors and may be more specific in diagnosis.

Computed tomography of posterior uveal melanomas.

Computed tomographic (CT) scans were obtained from 48 patients with posterior uveal melanoma. The CT measurements of maximal and minimal basal diameters and thickness of each tumor were compared with the assessments of these tumor dimensions obtained by ophthalmoscopic estimation (basal diameters only) and standardized A-scan ultrasonography (thickness only) and with the gross pathologic measurements of these tumors. The correlation between measurements of tumor thickness by CT scanning, standardized A-scan ultrasonography, and gross pathologic analysis was substantially better than that between the CT, ophthalmoscopic, and gross pathologic measurements of tumor basal diameters. Computed tomographic scanning appears to be a good method for determining the in vivo size of choroidal and ciliary body melanomas.

Diagnosis and evaluation of spondylolisthesis and/or spondylolysis on axial CT.

A critical review was made of the CT findings in 300 patients who underwent axial CT of the lumbar spine in which spondylolysis and/or spondylolisthesis had been diagnosed. Findings indicate that axial CT is superior to conventional radiographs in several areas: (1) for consistent and accurate demonstration of spondylolysis, (2) for disclosing the various changes in the apophyseal joints associated with degenerative and reverse spondylolisthesis, and (3) for uncovering minimal degrees of spondylolisthesis by the presence of a pseudobulging disk in many cases with equivocal or negative radiographs. Axial CT is a highly accurate method for diagnosing and evaluating spondylolysis and all types of spondylolisthesis.

Role of CT scanning in the superior vena cava syndrome.

The value of computerized tomographic (CT) studies was compared to other imaging procedures in 18 consecutive patients with the superior vena cava syndrome (SVCS) during a 47-month period. Sixteen of these cases had proved malignancy. In addition to tumor masses, CT findings included effacement, compression, and displacement of the great vessels and the presence of thrombi and collateral blood flow. Significantly, tumor was demonstrated in the region of the superior vena cava in five patients in whom a definite mass could not be diagnosed by other means. CT scanning in a sixth case revealed that although mediastinal tumor was present it was not located in the immediate region of the occluded vessels. CT was corroborative and helpful in planning therapy in all but one of the remaining patients. CT scans appear to be of most value in cases of SVCS in whom other modalities cannot demonstrate tumor and, particularly, in excluding recurrent tumor in previously treated patients.

Choroidal melanoma: comparison of CT, fundoscopy, and US.

Computed tomography (CT) was compared with fundoscopy and ultrasound (US) in 62 patients with primary choroidal melanoma. All lesions were detected with CT and fundoscopy and all but one with US. Of five cases of extrascleral extension, four were identified with CT and fundoscopy and two with US. CT best depicted the extent of retrobulbar tumor. Tumor thickness was best evaluated with CT, with good correlation between CT and US. Tumor enhancement was noted in all 51 patients who had both noncontrast and contrast CT. Because of its higher density, tumor could be distinguished from retinal detachment on CT scans in most cases.

Spontaneous regression of herniated nucleus pulposus.

Spontaneous regression of herniated nucleus pulposus has not been previously documented. Reported here are 11 patients in whom there was unequivocal regression or disappearance of a herniated lumbar disk on follow-up CT study. Two patients with herniated disks were without symptoms. In the nine patients with symptoms, those attributed to the original herniation disappeared or were diminished in all cases. The mechanism of regression of a disk herniation is unknown. Whether or not regression of herniated disk is a frequent occurrence in patients who recover with conservative therapy should be investigated by more frequent use of follow-up CT scans.

Computed tomography of lumbosacral conjoined nerve root anomalies. Potential cause of false-positive reading for herniated nucleus pulposus.

Conjoined origin anomalies of lumbosacral nerve roots, if incorrectly interpreted, could be misdiagnosed as disc herniations on computed tomography (CT). Several characteristic CT features of these anomalies are presented that should distinguish them from herniated discs. A conjoined root anomaly was found in approximately 2% of the 8,000 lumbosacral CT scans.

Intravenous contrast-enhanced CT of the postoperative lumbar spine: improved identification of recurrent disk herniation, scar, arachnoiditis, and diskitis.

Unsuccessful relief of symptoms after back surgery is usually attributable to hypertrophic extradural scar or recurrent herniated disk. Their clinical and myelographic differentiation is difficult, yet important because reoperation is not always beneficial for scar removal. This article examines the usefulness of intravenous contrast-enhanced computed tomography for this problem. Forty-five postsurgical patients were studied; eight had subsequent surgery. In the four with hypertrophic scars, intravenous contrast enhancement of the scar allowed its recognition in each case; in the four with recurrent disk herniation, nonenhancement of the extruded disk allowed its recognition in three. In the other 37 patients who were not reoperated, 33 were believed to have scar on the basis of contrast enhancement. Continuous contrast infusion during scanning, absolute avoidance of patient movement, and careful consideration of other structures in the spinal canal are important in interpretation. The method seems promising for more accurate evaluation of failed back surgery, including the recognition of diskitis.

The Diagnostic Imaging Information Center.

The authors have developed a Diagnostic Radiology Imaging Information Center, in which the physician can see at a glance, with minimum expenditure of time and maximum emphasis on relevance, a summary of the patient's studies and procedures done in the x-ray department.

Computed tomography and aging: results in a normal elderly population.

CT studies on 212 normal elderly individuals were analyzed for ventricular enlargement and cortical atrophy. Results show a positive correlation between ventricular enlargement and age with greater degrees of ventricular enlargement and cortical atrophy in men as compared to women. While some degree of atrophy is common in normal elderly individuals it is mild, minimal, or noexistent in 86%.

CT Identification of postlaminectomy pseudomeningocele.

A postlaminectomy pseudomeningocele is a spherical, fluid-filled space with fibrous capsule lying dorsal to the thecal canal in the laminectomy opening that occasionally develops after surgery. Eight cases were found in 400 symptomatic postlaminectomy patients undergoing computed tomographic examination. The contents are of cerebrospinal fluid density and may or may not have demonstrable communication with the subarachnoid space. Whether they are the cause of symptoms is conjectural; none of these eight patients had surgical removal.

CT appearance of the adolescent and preadolescent pituitary gland.

Coronal computed tomographic scans of the pituitary gland in 27 normal children, adolescents, and young adults (ages, 8-21 years) and in a comparison group of adults (ages, 24-91 years) were evaluated retrospectively to test the applicability of published criteria for size and configuration of normal adult pituitary glands to younger patients. Statistically significant differences were found between the two groups, indicating that the pituitary gland in adolescents, particularly girls, is larger than in younger or older patients. The authors suggest that pubertal pituitary hyperplasia accounts for these findings. They conclude that standards for normal pituitary glands are probably inappropriate for adolescents.

High-resolution CT of lesions of the optic nerve.

The optic nerves are well demonstrated by high-resolution computed tomography. Involvement of the optic nerve by optic gliomas and optic nerve sheath meningiomas is well known. However, nonneoplastic processes such as increased intracranial pressure, optic neuritis, Grave ophthalmopathy, and orbital pseudotumor may also alter the appearance of the optic nerve/sheath on computed tomography. Certain clinical and computed tomographic features permit distinction of these nonneoplastic tumefactions from tumors.

CT diagnosis of broncholithiasis.

Computed tomography clearly demonstrated broncholithiasis rather than suspected malignancy as the cause of segmental atelectasis of the right middle lobe. Possible technical limitations as a source of error are presented.

The interface sign: a computed tomographic sign for distinguishing pleural and intra-abdominal fluid.

On computed tomographic scans of the upper abdomen the interface sign can help distinguish pleural and intra-abdominal fluid readily and accurately. A hazy interface between the fluid and liver or spleen is characteristic of pleural fluid. A sharp interface is characteristic of ascites. The interface sign has proved to be accurate in 30 consecutive cases.