Helical computed tomography at 1.5:1 pitch reconstructed at 15-mm and 7-mm intervals for examination of patients with suspected metastatic disease.

OBJECTIVE: To document the need for overlapped reconstruction when using helical computed tomography (CT) software that reconstructs 10-mm-collimation, 1.5:1-pitch images at 15-mm intervals in follow-up examination of patients with suspected metastatic disease. PATIENTS AND METHODS: Forty consecutive patients with known or suspected metastatic disease were examined with helical CT at 10-mm collimation and 1.5:1 pitch. The studies were examinations of the chest, abdomen and pelvis; the chest and abdomen; or the abdomen and pelvis. Two image sets, one prospectively reconstructed at 15-mm intervals and the other retrospectively reconstructed at 7-mm intervals, were independently reviewed by three radiologists, and the number, size and location of lesions were documented. Differences in interpretation were resolved by consensus. The lesions detected on the two sets of images were classified according to lesion size and location, and the results were analysed by multivariate analysis of variance with repeated measures. RESULTS: Images reconstructed at 7-mm intervals revealed a total of 436 lesions, 127 (41%) more than were revealed by images reconstructed at 15-mm intervals. The number of lesions less than 1 cm in diameter that were visible in the two sets of images was significantly different (p = 0.018). However, there was no significant difference between the two sets of images in terms of lesion location. CONCLUSION: Metastatic lesions may be missed by helical CT at 1.5:1 pitch if overlapped reconstruction is not performed.

Periportal halo: a CT sign of liver disease.

Periportal halos are defined as circumferential zones of decreased attenuation identified around the peripheral or subsegmental portal venous branches on contrast-enhanced computed tomography (CT). These halos probably represent fluid or dilated lymphatics in the loose areolar zone around the portal triad structures. While this CT finding is nonspecific, it is abnormal and should prompt close scrutiny of the liver in search of an underlying etiology. Periportal halos which may be due to blood are commonly seen in patients with liver trauma. Periportal edema may cause this sign in patients with congestive heart failure and secondary liver congesion, hepatitis, or enlarged lymph nodes and tumors in the porta hepatis which obstruct lymphatic drainage. This CT sign has also been observed in liver transplants (probably secondary to disruption and engorgement of lymphatic channels) and in recipients of bone marrow transplants who might develop liver edema from microvenous occlusive disease. While the precise pathophysiologic basis of periportal tracking has not been proven, it represents a potentially important CT sign of occult liver disease.

Color Doppler sonography in the evaluation of the adult acute scrotum.

Color Doppler sonography (CDS) was used to evaluate 35 adult males with acute scrotal discomfort. Correlative nuclear scintigraphy was performed in 15 patients. Surgical correlation was available in 10 patients with clinical follow-up in the remaining 25. The complete absence of intratesticular color flow was used as our criterion for testicular ischemia. This was found to be 100% sensitive and 100% specific in 8 patients with surgically confirmed testicular ischemia. Spontaneous detorsion was noted in one patient with hyperemia demonstrated by color imaging. Increased color flow was found in 20 patients with the clinical impression of scrotal inflammation. Nuclear scintigraphy and color Doppler imaging had 100% agreement in 15 patients. Color Doppler sonography is a useful and highly accurate diagnostic method in the evaluation of patients with the acute scrotal syndrome. Color flow imaging is comparable to nuclear scintigraphy in the diagnosis of testicular ischemia.

Long bicipital tendon of the shoulder: normal anatomy and pathologic findings on MR imaging.

The tendon of the long head of the biceps muscle (long bicipital tendon) has a complex course from its muscle belly to its insertion onto the supraglenoid tubercle/glenoid labrum. It is stabilized by numerous tendinous and ligamentous structures and is, in turn, partly responsible for maintenance of normal glenohumeral function. In this report we describe the anatomy of this tendon, correlating high-resolution MR images with cryomicrotome sections. We illustrate typical MR findings in pathologic conditions affecting the long bicipital tendon sheath, the substance of the tendon, and finally the tendon position.

Color Doppler sonography in the evaluation of erectile dysfunction.

Color Doppler sonography can be useful in the evaluation of erectile dysfunction, which can result from psychogenic, endocrinologic, neurogenic, pharmacologic, and vasogenic causes. It is used to determine the integrity of the vascular mechanism. After an intracavernosal injection of a vasodilatory agent, color Doppler sonography is performed to evaluate cavernosal arteries and dorsal vessels. Color flow imaging allows direct visualization of intrapenile anatomy, vascular variants, and disease. It is also helpful in demonstrating transitions in cavernosal and dorsal blood flow. Color Doppler sonography is combined with spectral interrogation of the cavernosal arteries and dorsal veins to help determine peak systolic and end-diastolic velocities. Cavernosal artery size and systolic velocities help diagnose arterial insufficiency. Recent work on cavernosal artery diastolic flow and dorsal vein flow has indicated that color Doppler sonography, when correlated with cavernosographic findings, may be helpful in diagnosing venous incompetence. Temporal variations in transitions in cavernosal artery and dorsal vein flow during various stages of erection are important in the accurate diagnosis of vasogenic impotence.

Color Doppler sonography in the evaluation of erectile dysfunction: patterns of temporal response to papaverine.

Most studies of duplex Doppler sonography for the assessment of erectile dysfunction involve determination of peak systolic velocities 5 min after intracavernosal injection of papaverine. The purpose of this study was to determine the effect of the timing of Doppler measurements of flow after papaverine injection for establishing the presence of arterial and venous abnormalities. Color Doppler sonography was performed in 75 patients for evaluation of vasculogenic impotence. After intracavernosal injection of 60 mg of papaverine, measurements of peak systolic and end-diastolic velocities were obtained in each cavernosal artery at 5-min intervals for a total of 30 min. A peak systolic velocity of less than 25 cm/sec was used as the threshold for arterial insufficiency. An end-diastolic velocity of greater than 5 cm/sec was used to predict venous incompetence. Scanning was performed for direct assessment of dorsal venous flow. Thirty patients were subsequently evaluated by cavernosometry and cavernosography. In most patients (76%), maximum response to papaverine was achieved within the first 5 min. In eight patients, significant increases in systolic velocity were seen only after 5 min. In 10 patients, significant changes in end-diastolic velocity between 5 and 30 min resulted in diagnostic reclassification. Data acquisition for 30 min significantly improved the sensitivity (95%) and specificity (83%) for the prediction of venous incompetence in patients with correlative cavernosography. Transient, early dorsal vein flow was noted in normal subjects. Persistent dorsal vein flow had an 80% sensitivity and 100% specificity for venous incompetence. Our results suggest that, when using color Doppler sonography, gathering data for 30 min may improve the prediction of vasculogenic impotence.

Radiologic imaging of splenic anomalies.

Knowledge of the anatomy, embryology, and congenital anomalies of the spleen is needed in order to avoid pitfalls in the interpretation of abdominal imaging studies such as CT and sonography. For this reason, this pictorial essay illustrates the anatomy, embryology, and radiologic images of congenital anomalies of the spleen.

Diagnosis of ectopic pregnancy: endovaginal vs transabdominal sonography.

During a 25-month period, 193 women with the clinical diagnosis of suspected ectopic pregnancy had transabdominal and endovaginal sonograms. Most had quantitative determinations of serum human chorionic gonadotropin (HCG). Endovaginal sonography was diagnostic of ectopic pregnancy in 23 (38%) of the 60 patients with surgically proved ectopic pregnancies: transabdominal sonography was diagnostic in 13 patients (22%). All 83 intrauterine pregnancies were identified with endovaginal sonography, compared with 34 identified with transabdominal sonography. Endovaginal sonography was somewhat more helpful in the diagnosis of missed abortion and blighted ovum. Eighty endovaginal sonograms were classified as indeterminate as compared with 141 transabdominal studies. This indeterminate group included patients with complete abortions, ectopic pregnancies without sonographic evidence of an extrauterine gestation, incomplete abortions, and patients with subsequent negative serum levels. As in prior reports, endovaginal sonography was superior to transabdominal sonography in the evaluation of suspected ectopic pregnancies. Overall, endovaginal sonography was diagnostic in 113 patients, whereas transabdominal sonography was diagnostic in 52 patients. The finding of an extrauterine fetal pole or embryo was diagnostic for an ectopic pregnancy. Pelvic fluid, the appearance of the endometrium, and a single positive serum HCG determination were not helpful in making the diagnosis of ectopic pregnancy.

Traumatic fracture of the pancreas: CT characteristics.

Pancreatic fracture is a rare injury caused by blunt abdominal trauma. Few proven cases have been diagnosed by abdominal CT. The typical clinical triad of upper abdominal pain, leukocytosis, and hyperamylasemia is nonspecific. Abdominal CT gives the best opportunity for an immediate diagnosis. Nevertheless, few cases of traumatic pancreatic fracture have been diagnosed by abdominal CT within 24 h following injury and proven at laparotomy. In this report we describe five cases of traumatic pancreatic fracture identified on CT; four cases were verified at laparotomy. Traumatic pancreatic fracture generally occurs as a transverse transection across the neck of the pancreas. Commonly, an accompanying injury to other visceral organs is present. The diagnosis of pancreatic fracture requires a high index of suspicion with close scrutiny of the CT images.

Color Doppler sonographic imaging in the assessment of upper-extremity deep venous thrombosis.

Color Doppler flow imaging with linear-array transducers was performed in 130 extremities in 91 patients with suspected upper-extremity deep venous thrombosis. Thrombi were detected in 39 studies (30%). Eighty-four patients had either imaging examinations (22 studies comprising venography in 20 patients, CT in one, and MR imaging in one) or clinical follow-up (99 studies) for correlation. In studies with imaging correlation, the sensitivity of the Doppler studies was 78% and the specificity was 92%. There were two false-negative examinations in which the proximal subclavian vein either could not be imaged or the anatomy was distorted. There was one false-positive color Doppler diagnosis of deep venous thrombosis in a case of partial obstruction of the subclavian vein caused by extrinsic compression. There were no known additional errors in color Doppler imaging in patients who had clinical follow-up. Four cases of isolated superior vena cava or proximal innominate vein obstruction were missed by color Doppler imaging. Color Doppler flow imaging is an accurate, noninvasive method for the evaluation of upper-extremity deep venous thrombosis. Other imaging tests may be required when the color Doppler study is negative and central venous thrombosis is suspected.

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.

Color Doppler flow imaging of the normal and abnormal orbit.

Twenty-six normal orbits (16 subjects) and seven patients with suspected orbital disease were studied with color Doppler flow imaging CDFI). Arterial structures consistently identified included the ophthalmic artery, central retinal artery, and posterior ciliary branches. The terminal lacrimal branch was seen in the majority of orbits (n = 19). Venous structures consistently seen included the central retinal vein and venae vorticosae; the superior ophthalmic vein was identified in the majority of normal orbits (n = 22). Response of the superior ophthalmic vein to the Valsalva maneuver was assessed in six of the normal subjects (12 orbits). Retrograde flow was typically seen during the maneuver and accentuated antegrade flow after cessation of the maneuver. Pathologic entities correctly diagnosed with CDFI included a dural arteriovenous malformation (AVM) with spontaneous carotid-cavernous fistula, an orbital AVM, and superior ophthalmic vein thrombosis. Vascular lesions were excluded in two patients with orbital masses. Bilaterally enlarged superior ophthalmic veins were identified in a patient with unilateral symptoms suggestive of a varix; CDFI results were confirmed with computed tomography, but orbital venograms were interpreted as normal. These findings suggest that CDFI may be helpful in the evaluation of suspected vascular orbital disease.

Prospective comparison of radionuclide, computed tomographic, sonographic, and magnetic resonance localization of parathyroid tumors.

The appropriate choice of imaging techniques to localize parathyroid tumors preoperatively remains controversial. We report the first prospective, blinded study to compare the efficacy of four imaging modalities in 100 patients with primary hyperparathyroidism (pHPT). Patients were examined by computer-assisted thallium 201/technetium 99m subtraction scintigraphy (TTS), computed tomography (CT), ultrasonography (US), and magnetic resonance (MR). Each study was performed and interpreted independently. Subsequent neck exploration and "curative" parathyroidectomy allowed correlation of surgical findings with imaging reports to score their accuracy. Overall sensitivities of the four imaging modalities were TTS, 73%, CT, 68%, US, 55%; and MR, 57%; with respective specificities of 94%, 92%, 95%, and 87%. Sensitivities for lesions located below the thyroid gland (thymic tongue and mediastinum) were TTS, 90%; CT, 46%; US, 44%; and MR, 50%; with respective specificities of 100%, 99%, 100%, and 94%. There was a significant increase in overall sensitivity when TTS and CT (90%, p less than 0.01) or TTS and US (85%, p less than 0.05) were used together; however, the combination of any three or even four imaging modalities did not increase sensitivity further. For small parathyroid tumors (less than or equal to 250 mg), no imaging technique had a sensitivity of more than 50%. None of the imaging studies accurately localized small hyperplastic parathyroid glands found in patients with multiple gland disease. Preoperative parathyroid imaging may not be indicated in pHPT patients undergoing first-time neck exploration because surgeons experienced in parathyroid surgery have a 93% to 96% cure rate.

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.