Periportal tracking in hepatic trauma: CT features.

In retrospective review, 51 cases of hepatic trauma were analyzed for type and location of injury. More than half of these cases (62%) demonstrated periportal zones of decreased attenuation, which is presumed to represent blood in the periportal region. This finding has been termed "periportal tracking" and may be an important sign of subtle liver injury.

Stenosis of the internal carotid artery: assessment using color Doppler imaging compared with angiography.

The percentage of diameter stenosis of the internal carotid artery was estimated directly from color Doppler images obtained in both longitudinal and transverse planes and compared with the results of digital subtraction angiography in 49 patients (95 carotid arteries). Peak systolic velocity measurements were obtained by placing the sample volume in the highest-velocity flow stream with the angle-correction cursor parallel to the color-encoded lumen. Arterial stenoses were categorized on a grade 1-5 scale: 1 = 0-15%, 2 = 16-49%, 3 = 50-75%, 4 = 76-99%, and 5 = occlusion. Percent diameter stenosis could not be determined in 12 color Doppler flow imaging studies (13%) due to calcified plaque. Of the remaining 83 arteries evaluated by both techniques, the respective categories by color Doppler flow imaging/angiography were grade 1 (16/26), grade 2 (25/24), grade 3 (30/19), grade 4 (5/8), and grade 5 (7/6). Percent diameter stenosis determined by color Doppler flow imaging was greater than by angiography in 25% and less than by angiography in 4%. Peak systolic velocity measurements did not separate the hemodynamically insignificant (less than 50% diameter stenosis) grade 1 and grade 2 lesions, but were in agreement in 86% of grades 3-5 stenotic categories, as determined by measurements from the color Doppler flow image. A direct measurement of percent diameter stenosis from the color Doppler flow image was possible in 87% of cases. Peak systolic velocity provided correlative diagnostic information when assessing hemodynamically significant lesions.

Color Doppler evaluation of arterial stenoses and occlusions involving the neck and thoracic inlet.

Color Doppler flow imaging is a new technique providing simultaneous display of a gray-scale tissue and a color-flow vascular image. We demonstrate its ability to predict accurately occlusions of numerous vessels, including the internal carotid, external carotid, common carotid, subclavian and innominate arteries. Alterations in flow direction and changes in spectral wave form provide useful clues to the presence of these occlusions. The cases are correlated with angiographic findings and functional flow diagrams of the hemodynamic changes involved.

Color Doppler ultrasound imaging of lower-extremity venous disease.

A color Doppler ultrasound imaging device was used to evaluate 475 patients with suspected lower-extremity venous thrombosis. Occlusive and nonocclusive femoral and popliteal thrombi were detected in 200 studies (42%). In phase 1 of the study (240 examinations), peripheral augmentation with the use of periodic calf compression was required to show color flow throughout the femoropopliteal venous segment. In phase 2 (235 examinations), with a software upgrade to enhance detectability of slow flow, spontaneous flow could be appreciated in the normal, partly thrombosed, and recanalized femoral popliteal veins without augmentation. Augmentation was often necessary to view tibioperoneal veins. Of the total study group, conventional venography was performed for correlation in 47 patients. In the other patients, clinicians relied on the color Doppler test for the definitive diagnosis of the presence or absence of femoral popliteal venous thrombosis and treated these patients on the basis of the color Doppler test result. In the femoral veins, color Doppler studies and venography agreed in all 12 positive and 35 negative cases. In the popliteal veins, there was agreement in five isolated popliteal thromboses and in 10 femoral popliteal thromboses; there were two false-negative color Doppler studies of isolated popliteal thromboses. In four patients, Doppler studies detected nonocclusive thrombus not evident on venography. Color Doppler imaging is easy to perform and does not require augmentation to view color flow in the femoropopliteal venous segment. Eccentric thrombus and partially canalized thrombus can be shown. Initial experience suggests color Doppler imaging may be useful in the detection of tibioperoneal venous thrombosis.

High resolution surface coil magnetic resonance imaging of the joints: anatomic correlation.

Magnetic resonance imaging appears to be a particularly promising approach to the evaluation of articular and periarticular abnormalities. Its ability to produce images in multiple planes directly (without reconstruction) provides a unique advantage over CT for the radiologist when he attempts to interpret the complex three dimensional anatomy of most joints. The inherent contrast resolution of MR is excellent, and with the use of surface coils, spatial resolution is sufficient to permit the identification of the small soft tissue structures in and around joints. Artifacts generated by respiratory and cardiac motion are not a problem in MRI of the joints as they are in MR scanning of the body. Based on all these qualities, we believe that MRI will play an important role in the diagnosis of joint abnormalities.