Observer accuracy in the detection of pulmonary nodules on CT: effect of cine frame rate.

AIM: To assess the effect of cine frame rate on the accuracy of the detection of pulmonary nodules at computed tomography (CT). MATERIALS AND METHODS: CT images of 15 consecutive patients with (n = 13) or without (n = 2) pulmonary metastases were identified. Initial assessment by two thoracic radiologists provided the "actual" or reference reading. Subsequently, 10 radiologists [board certified radiologists (n = 4) or radiology residents (n = 6)] used different fixed cine frame rates for nodule detection. Within-subjects analysis of variance (ANOVA) was used to evaluate the data. RESULTS: Eighty-nine nodules were identified by the thoracic radiologists (median 8, range 0-29 per patient; median diameter 9 mm, range 4-40 mm). There was a non-statistically significant trend to reduced accuracy at higher frame rates (p=0.113) with no statistically significant difference between experienced observers and residents (p = 0.79). CONCLUSION: The accuracy of pulmonary nodule detection at higher cine frame rates is reduced, unrelated to observer experience.

Dual origin of the vertebral artery mimicking dissection.

Vertebral artery injury may occur at the time of cervical fracture or dislocation. Congenital vertebral artery variations, especially a double vertebral artery origin, may be responsible for angiographic findings that mimic vertebral artery dissection. Two cases of cervical spine fracture with ipsilateral double vertebral artery are presented. Conventional cerebral angiography is the easiest and best way to make this diagnosis and to exclude vertebral artery dissection.

Midline anterior atlas clefts: CT findings.

Anterior atlas clefts (AACs) are rare developmental variants that may mimic fractures. Due to the potential severe implications of craniocervical junction trauma, expeditious differentiation between a Jefferson burst fracture and a congenital cleft is essential in trauma patients. Three cases of AAC are presented. Two cases demonstrated incidental AACs; the third case was associated with a Jefferson burst injury. Computed tomography is most helpful in evaluating the integrity of the atlas; however, plain radiography or pluridirectional tomography are best for evaluating displacement of the lateral masses of C1 in relation to C2.

Hyperdense middle cerebral artery sign on CT: efficacy in detecting middle cerebral artery thrombosis.

The hyperdense middle cerebral artery sign is a CT predictor of the development of a large cerebral infarct. The limits of detectability were tested in a blinded, then unblinded analysis of CT scans from 25 acute stroke patients. In the initial blinded analysis, sign detection exhibited the following mean values: sensitivity, 78.5%; specificity, 93.4%; positive predictive value, 66%; negative predictive value, 96.4%; accuracy, 91.3%. Kappa statistics analysis indicated poor interobserver agreement (k = .38). Results of unblinded analysis were as follows: sensitivity, 69%; specificity, 94.4%; positive predictive value, 82.8%; negative predictive value, 88.7%; accuracy, 87.3%. There was fair unblinded interobserver agreement (k = .53). Unblinded analysis had a lower false-positive frequency and did not increase the number of true-positive determinations. We conclude that detection of the hyperdense middle cerebral artery sign on CT scans by multiple observers is a sensitive, accurate, and predictive indicator of middle cerebral artery thromboembolism.

Complications of intravenous digital subtraction angiography.

Extracranial carotid occlusive disease can be evaluated with either intravenous (IV) digital subtraction angiography (DSA) or standard angiography. In a prospective study, complications related to 500 IV DSA examinations occurred in 16.6% of patients, including local complications in 2.0%, systemic complications in 15.0%, and neurologic complications in 3.0%. A permanent neurologic deficit occurred in one patient. Complications related to 150 standard angiograms occurred in 7.3% of patients, including local complications in 4.0%, systemic complications in 3.4%, and neurologic complications in 0.7%. There were no permanent neurologic deficits. Serious systemic and neurologic complications occurred in 8.2% of patients during IV DSA and 2.7% of patients during standard angiography. The rapid injection of high volumes of hypertonic contrast media during IV DSA and the resultant hemodynamic and cardiac electrophysiologic changes account for the higher incidence of complications with IV DSA.

Metrizamide examination of traumatic lumbar nerve root meningocele.

Demonstration of traumatic lumbosacral root avulsion is a rare clinical entity because the bony pelvis offers support and protection to the nerve roots against stretching and rupture. Major vehicular trauma producing unstable pelvic fractures allows lumbosacral root avulsion to occur, and the 18th well-documented case is reported. Delay in diagnosis of several months is common. Demonstration of traumatic meningoceles is important, and metrizamide offers better visualization of the root than does iodophendylate. Absence of the root in the meningocele is equated with avulsion.

Digital subtraction angiography with intravenous injection: assessment of 1,000 carotid bifurcations.

Digital subtraction angiography (DSA) with intravenous contrast injection was performed on 500 consecutive adult patients and evaluated for image quality of the carotid artery bifurcations. Diagnostic quality examinations were obtained in 974 common, 925 internal, and 904 external carotid artery segments. Sixty-two patients had standard carotid arteriography around the same time as DSA. Agreement of standard arteriograms with diagnostic quality DSA examinations was noted in 97 of 98 common, 94 of 95 internal, and 79 of 91 external carotid artery segments. All cases of complete carotid occlusion (14 of 14) were correctly interpreted by DSA. To identify a population with clinically significant stenosis, a 60% or greater reduction in diameter of the internal carotid was defined as a positive examination. Applying this criterion, the sensitivity, specificity, and accuracy of DSA as compared with standard arteriography was about 94%.

Modified venous catheter technique for digital angiography.

A 5-F dilating catheter that has been modified with side holes is described for venous injection digital angiography. This catheter can be rapidly placed in an antecubital arm vein in most patients without fluoroscopy, even in those patients whose arm veins are inadequate for other techniques. In studies of over 100 carotid arteries that were performed using this method, images of diagnostic quality have regularly been obtained.

Detachable balloon closure of carotid-jugular fistulas in dogs.

The authors' experience using the Debrun detachable balloon catheter system in occluding surgically-created carotid-jugular fistulas is described. Useful technical points in preparing and using the system are outlined. Technical failures were encountered both in creation of the fistula model and in use of the system, and their occurrence is documented. It is concluded that, when familiarization with the system's operation is attained, the detachable balloon catheter system promises to offer a valuable method of treatment of traumatic carotid-cavernous fistulas in humans.

Intracranial blood clot volume and geometric parameters determined from CT images.

A method of determining intracranial blood vlot volumes from CT images data is presented. This technique avoids dependence on regular geometric volume approximations. Studies are presented on phantoms of known volume (ranging from 3.5 to 108 cm3) but with varying size, shape, and density relative to the surrounding medium. For a wide range of differential densities across the boundary, these phantom results indicate that volumes may be calculated to an accuracy generally better than +/- 2 cm3. A series of clinical cases, principally hypertensive intracranial hemorrhages, have been studied to demonstrate the technique. Three-dimensional axes, which allow clot localization relative to cerebral anatomy, are defined using the anterior/posterior falx attachment points and the dorsum sellae. Clot volume, center of mass, vector of clot expansion, and shift of anatomical structures are determined. Correlation of these data with clinical outcome and surgery is discussed.

Iatrogenic carotid-cavernous fistula following Fogarty catheter thromboendarterectomy. Case report.

A case of iatrogenic carotid-cavernous fistula secondary to a Fogarty catheter thrombectomy is presented. The literature and seven previously reported cases are reviewed.