Computed tomography in aortobifemoral Y grafts

The fact that we have experience in assessing aortic aneurysms and the need for a noninvasive morphologic and hemodynamic method of examination for the follow-up of aortoiliac surgery motivated us to initiate a dynamic CT study of bifurcation prosthesis. Twenty-seven Y grafts (25 Dacron, 2 polytetrafluoroethylene) were studied by CT scan 1 month to 7 years postoperatively. There were normal CT findings in 16 patients, neointima formation in 6, graft occlusion (1 limb of the Y graft) in 3, and dilatation of the prosthesis in 2. Patent grafts showed enhancement of contrast medium. CT scans corresponded to clinical findings in all instances. Because of its noninvasiveness, assessment of perivascular changes, and semiquantitative measurements, dynamic CT may be applied in the follow-up of aortofemoral bifurcation grafts.     

Computed tomography of the sternum and its articulations

The chest wall presents diagnostic difficulties for both the clinician and the radiologist. Because of normal variations in anatomy and ossification, analysis of the sternal region can be particularly confusing. We reviewed the normal computed tomographic (CT) appearance of the sternum in 354 patients. Important normal sternal variants included cortical unsharpness along the posterior aspect of the manubrium, lateral surfaces of the body, and at the sternal fibrocartilaginous articulations; soft tissue prominence at the junction of the sternum and costochondral cartilage; and bony sclerosis at the transitions from manubrium to body and from body to xiphoid. In seven patients with clinically significant sternal abnormality, key CT features were abnormal soft tissue mass (7/7), destruction or irregularity of the cortical contour (7/7), and abnormal increased attenuation of bone (1/7). CT should be the radiologic study of choice in patients with suspected abnormality of the sternum and its articulations.     

Computed tomography in spastic cerebral palsy

Summary Eighty-three children with spastic cerebral palsy (CP) were examined with cranial CT. In 56 cases the CT findings were abnormal. The most frequent abnormality was atrophy, present in 44 patients. The frequency of pathologic CT increased with severity of the CP. Patients with CP of postnatal aetiology more often had abnormal CT than patients with other known causes. Pathologic CT findings were seen more often in patients with seizures than in patients without. Infarctions and hemiatrophy were much more frequent in patients with hemiplegia than in patients with other types of spastic CP. A special kind of central atrophy, called isolated atrophy around the cella media, is described. This condition was seen in 20% of cases, most often in hemi- and paraplegic patients. Early infarctions in the border areas between the vascular territories of the internal carotid and the posterior cerebral artery may be the reason for this kind of atrophy.     

Computed tomography of intrathecal thorotrast

Summary Thorotrast is distributed in the cerebral subarachnoid space in a distinctive manner. Computed tomography is an excellent method for demonstrating this distribution.     

Computed tomography of stress fracture

An athletic young female developed gradual onset of pain in the right leg. Plain radiographs demonstrated solid periosteal reaction in the tibia compatible with stress fracture. She stopped sport activites but her pain continued. Follow-up radiographs of the tibia revealed changes suspicious for osteoid osteoma. Computed tomography (CT) scan demonstrated periosteal reaction, but in addition, lucent fracture lines in the tibial cortex were evident. CT obviated the need for more invasive diagnostic procedures in this patient. In selected cases CT may be useful to confirm the diagnosis of stress fracture when plain radiographic or routine tomographic studies are not diagnostic.     

Computed tomography in ossification of the posterior longitudinal spinal ligament

Summary A patient with cervical myelopathy was found to have extensive ossification within the posterior longitudinal ligament. Computed tomography of the spine was of value for precisely defining the degree of narrowing of the spinal canal. The nature of this disease entity is discussed.     

Computed tomography of intramuscular myxoma

Computed tomography (CT) was performed in seven patients with intramuscular myxoma. All lesions were well demarcated, of homogeneous appearance and attenuation values ranging from 10 to 60 (HU). The tumor size, as estimated at CT, correlated well with the size of the surgical specimen, which is in contrast to the findings in some high grade malignant sarcomas.     

Computed tomography of the human developing anterior skull base

The ossification of the anterior skull base, especially the lamina cribrosa, has been studied by computed tomography and histopathology. Sixteen human fetuses, (referred to our laboratory for pathological examination after spontaneous abortion between 18 and 32 weeks of gestation) and three infants, (1, 2 and 6 years of age, respectively) were examined. The cartilaginous preformation of the anterior skull base creates a ‘pseudo-defect’ on CT in the coronal plane, even with ultra thin sections and high resolution CT. By the age of 6 years of life this ‘artefact’ is no longer, as the present ossification of the lamina cribrosa is, by that time, complete.     

Computed tomography in ophthalmology

Summary The practical value of density measurements with computed tomography of orbital lesions is demonstrated.     

Computed tomography in Alexander's disease

Summary A case of biopsy proven Alexander's disease is described with extensive low density lesions in both frontal lobes, which in our experience, and on survey of the literature have not been described previously.     

Computed tomography of intracerebral toruloma

Summary The CT features of intracerebral toruloma are described and the clinicopathological features briefly reviewed. The diagnosis of intracerebral toruloma should be considered when pulmonary opacities are associated with multiple intracerebral enhancing masses.     

Computed tomography in Alexander's disease

Summary Two cases of biopsy-proven Alexander's disease are described with computed tomographic changes which, in our experience and on survey of the literature, have not occurred in any other condition. Such changes in a child with a progressive condition consistent with Alexander's disease, strongly support the diagnosis.     

Computed tomography of cavernous sinus diseases

Summary We retrospectively analyzed CT scans of 21 cavernous sinus lesions in an attempt to discover CT findings helpful to the differential diagnosis. With the integration of various CT observations it was possible to categorize the lesions into inflammatory, vascular, benign neoplastic and malignant metastatic lesions with few exceptions. Four of 5 cases of septic cavernous sinus thrombophlebitis revealed unilateral or bilateral multiple irregular filling defects in the enhancing cavernous sinus with or without orbital inflammatory change. Four of 5 cases of carotid-cavernous fistula demonstrated unilateral or bilateral diffuse bulging and homogeneous enhancement of the cavernous sinus with obliteration of normal low densities of cranial nerves and gasserian ganglion. Dilatation and tortuosity of superior ophthalmic vein were also associated. Four of 5 cases of benign neoplastic lesion showed well-circumscribed enhancing masses confined to the cavernous sinus with pressure erosion or hyperostosis of adjacent bone. Five of 6 cases of malignant metastatic lesion showed changes suggesting malignancy such as destruction of adjacent bone or associated manifestations of intracranial spread. As compared with the axial scan, coronal scans proved to be more sensitive in detection of subtle cavernous sinus expansion, and superior in evaluation of intracavernous neural structures, relationships with the pituitary gland and changes in the skull base. Axial scans, however, were superior in detection of associated orbital and intracranial abnormalities. Scans in both projections are needed in the evaluation of most cavernous sinus diseases.     

Computed tomography in acute haemorrhagic leukoencephalitis

Summary Three patients with biopsy-proven acute haemorrhagic leukoencephalitis are described. All presented with an abrupt onset of focal neurological signs, pyrexia and leukocytosis. In two cases there was disturbance of consciousness. Computed tomography in each case revealed low density virtually confined to the white matter of the cerebral hemisphere; in one case there was central enhancement within the low density. The combined clinical and CT signs should strongly suggest the diagnosis.     

Computed tomography for small acoustic neuromas

Summary The minimal size of acoustic neuromas detectable by computed tomography (CT) is, according to the available literature, 1.5 to 2 cm. The new otoneurosurgical technic using the transtemporal and translabyrinthine approach necessitates an early diagnosis of neuromas protruding 1 cm or less into the cerebellopontine angle cistern. This seemed impossible with the available CT equipment. Eight proven acoustic neuromas 1 cm or less in diameter, detected with CT, are reported. Diagnostic criteria are elaborated. The study shows that small cerebellopontine angle tumors can be detected by use of CT machines of the newer generation which perform scanning with thin and overlapping slices.     

Computed tomography in management of medulloblastomas

Summary The neuroradiological studies of 116 patients with histologically verified medulloblastomas, which had been examined with plain and contrastenhanced computed tomography (CT), were reviewed. The typical CT appearances of a well-defined, hyperdense enhancing mass in the vermis, with surrounding oedema, occurred in 60% of this series. Atypical features include calcification (17%), cystic or necrotic regions (47%) or poorly defined margins and lack of enhancement (7%). Such features in a vermis mass presenting in the first decade, especially in a boy, should not be considered against the diagnosis of medulloblastoma, but may be misleading when the tumour predominantly involves a cerebellar hemisphere.     

Computed tomography in the diagnosis of cerebral abscess

Summary Computed tomography (CT) was performed 64 times on 22 patients with cerebral abscesses, using the 160x160 matrix EMI scanner. The diagnosis was based upon the demonstration of a localized low-attenuation area appearing, after the administration of contrast medium, as a high-attenuation annular rim ascribed to displaced and/or newly formed vessels, the so-called abscess membrane. CT is compared with the conventional diagnostic methods of neuroradiology. The differential diagnostic accuracy of CT is clearly superior to that of previous methods, including angiography, which, until now, we have considered the most accurate method.     

Computed tomography in the diagnosis and differential diagnosis of glioblastomas

Summary The CT patterns of 295 glioblastomas examined with pre- and postcontrast scans using an EMI scanner mark I (Matrix 160/160) have been reviewed and compared with the CT appearances of other brain tumors, metastases and abscesses. There is a great variety of CT patterns with glioblastomas. However, a garland-shaped CT appearance, representing a subgroup of ring-shaped lesions, seems to be most typical for glioblastomas since it was observed in 19% of ring-shaped glioblastomas but in only one out of 172 metastases and in no case of an astrocytoma grade II or an abscess in our series. The initial CT diagnosis, based on the CT finding, the patient's history and the clinical data, was correct in 69.8% of the glioblastomas, 41 recurrent glioblastomas included. In 12% of the cases the presence of a glioblastoma was within differential diagnosis. These results lead to the conclusion that in many cases additional diagnostic methods, such as serial scintigraphy and/or cerebral angiography, are required for a reliable differential diagnosis.     

Computed tomography in spinal tuberculosis

Exhaustive ciinicoradiologic and computed tomographic (CT) analysis of 114 cases of spinal tuberculosis seen between January 1983 and January 1989 is presented. The mechanisms of the spinal involvement are reviewed. CT helped to diagnose cases of spinal tuberculosis in their initial stages. Inaccessible fixed areas of spine were seen with ease on axial sections of CT. The extent and anatomic depiction of soft-tissue involvement as depicted on CT helps surgeons choose the appropriate surgical approach, which may affect future spinal stability.     

Computerized tomography in the investigation of groin masses following femoral catheterization

Pseudoaneurysm of the femoral artery is an uncommon complication of retrograde arteriography. It is sometimes difficult to clinically differentiate a pseudoaneurysm from a large hematoma. We present 13 cases of suspected femoral pseudoaneurysm following angiography which were investigated by computed tomography (CT). It is suggested that this is a useful procedure in the investigation of groin masses after catheterization.