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.

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.

A comparison of CT scanning and myelography in the diagnosis of lumbar disc herniation.

Computerized tomographic (CT) scanning of the fourth and fifth lumbar disc spaces with the GE CT/T8800 scanner followed by metrizamide myelography was obtained for 134 consecutive patients with suspected lumbar disc disease. There was an overall concordance rate of 85% between CT scanning and myelography. In those 52 patients treated by surgery, concordance between the CT and the myelogram was similar at 86.5%. Myelography and surgical findings were in agreement in 94.2% of cases, while CT findings and surgical finding agreed in 92.3% of cases. The authors' data indicate that the CT scan is as accurate as myelography in the diagnosis of lumbar disc disease. When the CT scan interpretation is supported by clinical findings, the myelogram may be eliminated in the preoperative patient. Myelography may be reserved for equivocal cases.

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.

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.

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.

The right mid-lung window.

On conventional chest radiographs, an area of diminished vascularity usually indicates focal disease. On CT scans of the chest, however, there is often a focal vascular deficiency in the right mid-lung that appears to be normal. In a study of 50 patients, diminished vascularity was noted at the level of the bronchus intermedius on 92% of the scans. The anatomical basis for this finding is discussed.

Esophagitis caused by oral medication.

Three cases of esophagitis caused by oral medication are reported: 2 were the result of prolonged use of quinidine tablets (producing focal subacute inflammation mimicking carcinoma in one and stricture in the other) and one occurred soon after ingestion of liquid KCl. Previous reports have implicated KCl tablets ("slow KCl"), tetracycline and doxycycline capsules, and ferrous sulfate tablets. The factors predisposing to this uncommon complication of oral medication are discussed. In all reported cases caused by KCl tablets, left atrial enlargement was present as the result of mitral stenosis.

Urticaria of the colon.

The clinical manifestations of colonic urticaria vary, depending on the presence of associated abnormalities. A case of an association between colonic urticaria and cecal volvulus is described.

Urographic and angiographic changes in acute unilateral pyelonephritis.

The pyelographic and angiographic changes in acute unilateral bacterial pyelonephritis are illustrated in our series of 12 patients. The radiographic abnormalities were completely reversible within a few weeks after clinical recovery. Complications (abscess) occurred in only one patient. Unilateral renal enlargement, diffuse or focal, impaired or absent excretory function, and attenuated calyces were the predominant findings; non-obstructive pelvicalyceal and/or ureteral dilatation were infrequent. Angiographic studies (fivepatients), performed to rule out vascular occlusion, tumour or carbuncle, showed attenuated and somewhat stretched intrarenal vessels associated with the diffuse or focal cortical swelling. Occasionally, a characteristic striated nephrogram is seen.