Traumatic lumbar hernia: CT diagnosis

A lumbar hernia usually involves protrusion of extraperitoneal fat or bowel through an area of weakness in the posterolateral abdominal wall bounded superiorly by the 12th rib, inferiorly by the iliac crest, posteriorly by the erector spinae muscle, and anteriorly by the posterior border of the external oblique muscle. Most are due to an acquired nontraumatic or congenital cause. Acute blunt abdominal trauma is a rare cause of lumbar hernia; to our knowledge, the CT diagnosis of this variety has not been reported. Since 1985, approximately 850 patients have undergone emergent abdominal CT for evaluation of acute abdominal trauma at our hospital; in seven of these patients, a traumatic lumbar hernia was diagnosed prospectively. In three patients, CT showed a flank hematoma with herniation of bowel through the lumbar triangle. CT showed pelvic fractures in three other patients, accompanied by herniation of bowel in one patient, herniation of extraperitoneal fat in another, and herniation of extraperitoneal fat and blood in the third. One patient had both a flank hematoma and a pelvic fracture with herniation of bowel. Acute traumatic lumbar hernia is a rare but significant abnormality that should be considered in patients with blunt abdominal trauma, especially in those with large flank hematomas and pelvic fractures. The hernia contents, associated injuries, and disrupted muscle layers are all well demonstrated on CT.     

Posterior fossa extraaxial cyst: diagnosis with metrizamide CT cisternography.

This study describes a new technique for the study of posterior fossa extraaxial cysts. Using metrizamide (Amipaque) CT cisternography, a rapid, simple, low morbidity method is now available which gives both anatomic and physiologic information that may obviate the need for pneumoencephalography and angiography. Two cases are reported; in a third the diagnosis was definitively excluded. By doing serial CT scans following the intrathecal introduction of metrizamide, data concerning the diffusion characteristics of these cysts as well as the accompanying hydrocephalus are obtained.     

Cerebrospinal fluid imaging using serial metrizamide CT cisternography

Summary Twenty-five patients studied by serial metrizamide (Amipaque) CT cisternography were used to analyze CSF kinetics. Delayed CSF flow patterns were noted in 7 patients, while intermediate patterns occurred in 4. The abnormal cisternogram was characterized primarily by ventricular reflux and stasis and secondarily by diminution of the parasagittal blush and a periventricular rim of decreased absorption. The intermediate group had minimal ventricular stasis after 24 hours and a normal parasagittal blush. After clinical and biochemical evaluation of the patient with dementia, CT scanning is usually indicated. If a profile suggestive of communicating hydrocephalus emerges, CSF kinetics can be monitored dynamically by CT scanning with metrizamide enhancement.     

CT diagnosis of thrombosis of dural sinuses in childhood

This paper describes the CT findings in five cases of cerebral and cerebellar sinovenous occlusion. Characteristic CT findings are the visualisation of the thrombosed sinuses and veins, known as the "filled triangle" and the "cord sign" on the control scan, and the "empty triangle" with tentorial and gyral enhancement after contrast enhancement. The high incidence of thrombosed internal cerebral veins and superior cerebellar veins with sinus thrombosis in children is remarkable. CT with both control and contrast enhanced scans will probably provide the correct diagnosis in the majority of cases.     

CT of extraarachnoid metrizamide instillation

Because CT of spinal extraarachnoid metrizamide collections may be misleading, we reviewed the postmetrizamide CT scans of 425 patients in order to characterize the appearance of subdural or epidural metrizamide. Eight patients were found to have extraarachnoid metrizamide contrast collections. In all patients, both the subarachnoid space and the extraarachnoid collection were opacified with metrizamide. In seven patients, a subdural collection of metrizamide created a mass upon the opacified subarachnoid space. Three of these subdural collections were less dense than the opacified subarachnoid compartment and simulated soft-tissue disease, including tumor and an arteriovenous malformation. The hypodense collections are probably a result of leakage of metrizamide and cerebrospinal fluid through the spinal needle defect. CT clues for diagnosing these potentially misleading subdural collections include preservation of the normal dural and epidural interface, identification of small islands of metrizamide within a suspected soft-tissue "mass," the presence of concomitant epidural contrast material collections, and the absence of adjacent vertebral-body destruction.     

Traumatic renal artery occlusion: CT diagnosis with angiographic correlation

Traumatic renal artery occlusion is a rare injury and may be clinically silent or vague in its presentation. In the appropriate clinical setting CT findings are diagnostic, enabling prompt arteriographic evaluation and early surgical intervention.     

Delayed metrizamide CT enhancement of syringomyelia: postoperative observations

Delayed metrizamide computed tomography (CT) was performed both preoperatively and postoperatively in 11 syringomyelia patients. Change of syrinx size between the studies was easily assessed on CT. The morphologic change of the syrinx gave useful information about its continuity. One of our cases had reoperation as a result of this CT information. All cases with Chiari I malformation still showed filling of the syrinx cavity by metrizamide after posterior fossa decompression and obex plugging. This supports the idea that the abnormal fluid circulation maintaining syringomyelic cavities is more than just the flow through the obex to the central canal but may also be from fluid passage through the cord substance.     

上盂唇前后撕裂:多层CT关节成像诊断的准确度及阅片者间可信度

目的评估多层CT关节成像对上盂唇前后(SLAP)损伤的诊断及分类的准确性与阅片者间的可信度。材料与方法本研究经机构审查委员会批准并获得知情同意。回顾性     

Cervical radiculopathy: prospective evaluation with surface coil MR imaging, CT with metrizamide, and metrizamide myelography

A prospective study was undertaken to compare the accuracy of surface coil magnetic resonance (SCMR) imaging, metrizamide myelography (MM), and computed tomography with metrizamide (CTM) in the determination of cervical radiculopathy. Surgical findings were the objective measure of accuracy. Fifty-two patients underwent all imaging studies. Studies were evaluated for disease location and type (bone vs. soft tissue). Twenty-eight patients underwent subsequent cervical surgery at 39 levels form an anterior interbody approach. Predictions made with SCMR imaging were surgically confirmed in 74% of patients, with CTM in 85%, and with MM in 67%. There was 90% agreement with surgical findings when SCMR imaging and CTM were used jointly, and 92% agreement when CTM and MM were used jointly, In general, SCMR imaging was as sensitive as CTM for identification of disease level, but not as specific for type of disease. MM was the modality least specific for disease type. The major advantage of CTM was its ability to distinguish bone from soft tissue, for which contrast material is unnecessary. SCMR imaging is a viable alternative to MM and, together with computed tomography, if needed, provides a thorough examination of the cervical region.     

Diagnosis of epidermoid cysts by metrizamide CT cisternography

Summary The authors describe three cases of intracranial epidermoid cysts specifically diagnosed by metrizamide CT cisternography. In CT cisternography of epidermoid cysts, metrizamide enters deep in the tumor clefts and depicts the lobulated margin of the tumor. We consider these findings are specific for this tumor and similar to the findings reported previously in pneumoencephalography or positive contrast cisternography.     

Determination of ventricular volume following metrizamide CT ventriculography

Summary Volume averaging, relatively slight differences in the mean attenuation coefficients of CSF and white/grey matter, and the irregular contours of the human ventricular system have so far seriously limited the accuracy of CT estimation of ventricular volume. Taking advantage of the high attenuation of metrizamide-containing CSF, we have developed three methods for computing ventricular volume after metrizamide CT ventriculography; these methods depend upon computer analysis of X-ray absorption data obtained from contiguous CT brain slices. All three methods were validated by CT scanning a formalin-fixed cadaver brain containing an epoxy-resin cast of the ventricular system. Calculated ventricular volumes were compared with the actual measured volume of the ventricular cast.     

Whole-brain CT digital subtraction angiography of cerebral dural arteriovenous fistula using 320-detector row CT

Introduction

The purpose of this study was to evaluate the usefulness of CT digital subtraction angiography (CTDSA) by using 320-detector row CT in the diagnosis and classification of cerebral dural arteriovenous fistula (dAVF) and comparing it with DSA as the standard reference.

Methods

A total of 29 CTDSA/DSA from 25 patients with dAVF were retrospectively evaluated by two neuroradiologists. The presence, Cognard classification, and feeding arteries of dAVFs on CTDSA were assessed according to DSA.

Results

DSA depicted 33 dAVFs in 28 cases. By consensus reading, CTDSA correctly detected 32 dAVFs in 27 cases and properly graded 31 lesions. The intermodality agreement for the presence and classification of dAVFs was excellent (kappa?=?0.955 and 0.921, respectively). CTDSA detected 77 of 109 feeding arteries (70.6 %) in 25 cases. The intermodality agreement for the feeding arteries was good (kappa?=?0.713).

Conclusion

Although CTDSA is limited in temporal and spatial resolution in comparison with DSA, it is an effective non-invasive tool for the detection and classification of dAVF.     

Patterns of spinal cord atrophy by metrizamide CT

Forty patients with cervical myelopathy underwent high-resolution computed tomography (CT) with intrathecal administration of metrizamide for evaluation of cervical spinal cord atrophy. Thirty of them showed evidence of either focal atrophic distortion or generalized accentuation of the anatomic surface features of the spinal cord. Patients with a Chiari malformation or syringomyelia were excluded. The characteristic features in cervical spondylosis and canal deformity include flattening of the ventral surface of the cord, central infolding, beaking of the lateral funiculi, and wasting of the dorsal surface of the cord. Patients with motor neuron disease showed a combination of anterolateral and posterolateral atrophy reflecting underlying degeneration of the anterior horn cells and/or corticospinal tracts, respectively. Those with monomelic motor neuron disease had a striking ipsilateral hemiatrophy of the spinal cord. Among those presenting with spastic paraparesis, seven with clinically definite multiple sclerosis showed diffuse atrophy or focal degeneration due to a localized plaque of demyelination. Two cases of cord neoplasm showed atrophy secondary to ascending or descending degeneration of the long tracts.