Search

We explored the agreement among radiologists in their evaluation of the appropriateness of individual requests for imaging procedures.We reviewed 318 noninterventional CT, sonographic, MR imaging, and nuclear medicine procedures ordered at a general internal medicine clinic during 8 months in 1995. Five subspecialty radiologists used data from the radiology request from and clinic notes to independently rate the appropriateness of each requested imaging procedure on a four-point scale. The radiologists were unaware of the results achieved by each procedure. Each case was reviewed by at least three radiologists, of whom at least one had relevant subspecialty expertise. Agreement among radiologists was analyzed using Cohen's kappa statistic and weighted kappa statistics and Cronbach's alpha statistic.Nonchance agreement (kappa) was .19 +/- .05; weighted kappa was .24 +/- .05. Interrater agreement was significantly greater than that expected from chance alone (p.01). The composite score, defined as the average of the radiologists' scores for each case, showed moderate reliability, as evidenced by a value for Cronbach's alpha of 70.In the absence of explicit criteria, we found modest but statistically significant agreement among radiologists about the appropriateness of individual requests for imaging procedures. The disagreement among radiologists highlights the importance of developing well-reasoned, explicit criteria by which to judge the appropriateness of diagnostic radiology procedures. Further study is needed to elucidate the relationship between appropriateness and actual patient outcomes.

This study was designed to prospectively compare helical CT with pulmonary angiography in the detection of pulmonary embolism in patients with an unresolved clinical and scintigraphic diagnosis.Twenty patients with an unresolved suspicion of pulmonary embolism were evaluated with contrast-enhanced helical CT and with selective pulmonary angiography. An average of 11 hr separated the two studies. The CT scans were obtained during one 24-sec or two 12-sec breath-holds. CT scans were interpreted without knowledge of the results of scintigraphy or angiography. Selective pulmonary angiograms were obtained with knowledge of the findings on the ventilation/perfusion scan only. The sensitivity and specificity of CT were compared with those of angiography for central vessels (segmental and larger) only and for all vessels.Eleven of the 20 patients had proved pulmonary embolism (seven in central vessels and four in subsegmental vessels only). When only central vessels were analyzed, CT sensitivity was 86%, specificity was 92%, and the likelihood ratio was 10.7. However, when subsegmental vessels were included, CT results were 63%, 89%, and 5.7, respectively.In our subset of patients, helical CT was only 63% sensitive. Subsegmental emboli are difficult to diagnose. Pulmonary angiography remains the study of choice. CT has a limited role in the evaluation of acute pulmonary embolism.

The development of hepatic cirrhosis triggers attempted repair through regenerative nodules of parenchyma among bands of scar tissue. Some authors believe that this regeneration initiates an evolutionary process that may lead to nodular enlargement and cellular dedifferentiation to malignancy. Both the destructive and reparative processes in cirrhosis produce changes that the radiologist must recognize when imaging the cirrhotic liver. This essay describes the CT and MR features of masses and masslike lesions in the cirrhotic liver, including the identifying characteristics and overlapping appearances of CT and MR.

This study was designed to investigate a variety of sonographic features of ureteric jets in order to define patterns of flow and ranges of flow values in an asymptomatic population. The following features of ureteric jets were measured during a period of up to 30 min in a group of 15 asymptomatic volunteers after oral hydration (the mean value was calculated on each side): peak velocity (mean, 57 cm/sec); jet duration (mean, 4.6 sec); and number of peaks and subpeaks (mean, 2.2). Several flow patterns were observed, including discrete jets, ureteric streaming, and rest periods. For each patient the ratios of values obtained on the left and right sides were calculated for peak velocity (1.00-1.74; mean, 1.26); jet duration (1.00-4.69; mean, 1.83); and jet frequency (1.00-1.21; mean, 1.11). The interjet interval (period between jets) ranged from 2 to 150 sec. Bolus volume and jet frequency showed simultaneous moment-to-moment variation. The frequency and velocity rather than the duration ratios may be of greatest value in identifying patients with normal ureterodynamics. Our findings challenge two current concepts of renal pelvic and ureteral response to changes in urine output: (1) ureters have a fixed maximal discharge rate and (2) bolus volumes do not change until this rate is achieved. Asymmetric moment-to-moment fluctuations observed in jet frequency suggest that prolonged examination may be necessary to confirm normal symmetry of jet frequency in some patients with suspected ureteric obstruction.

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.

The development of high-resolution computed tomographic (CT) imaging has substantially improved the radiologic examination of the lesser peritoneal sac (LPS). The fact that LPS anatomy remains obscure and difficult to remember often causes problems in the interpretation of CT as well as conventional radiologic examinations of the upper abdomen. This report reviews the embryologic development of the LPS, introduces a useful method for remembering three-dimensional LPS anatomy, and discusses LPS abnormalities on imaging examinations, with a special emphasis on the CT findings.

In a 3-year period, 21 intraabdominal bilomas developed in 18 patients. Fifteen of the patients had a solitary biloma, and the other three patients each had two separate concurrent bilomas. The major cause of biloma formation was postoperative bile leakage from a bile duct after laparotomy done primarily for surgery on the gallbladder or liver. Maximal diameter of the bilomas in the transaxial plane ranged from 2 to 19 cm. Sixteen of the bilomas were in the right upper quadrant, and five were in the left upper quadrant. Two large right-sided collections extended caudally into the lower abdomen. The contours of the bilomas were configured by the diaphragm, mesenteries, liver, and other abdominal organs. On CT and sonography, the bilomas were invariably well demarcated, but most did not have an identifiable capsule. CT did demonstrate a thin rim on four bilomas and a thick rim on one. In 19 bile collections, the CT numbers were less than 20 H. The combination of the clinical history, the location, and the CT appearance of the lesion led to the correct diagnosis in each case. Percutaneous drainage was an effective form of therapy that often eliminated the need for surgical drainage.

The supraclavicularfossa including the brachial plexus have traditionally been difficult to evaluate, both clinically and from an imaging standpoint. Conventional radiographs only depict indirect changes in the adjacent lung apex and skeletal structures. CT is currently the best technique for assessing the supraclavicular region [1 -5], but CT has several significant limitations, including a restriction to the axial imaging plane and streak artifacts from the shoulders. MR provides better soft-tissue contrast than CT, permits direct multiplanar imaging, and is not associated with streak artifacts. In addition, the superficial location of this area makes it accessible to local (surface) coils. Thus, MR has great potential in the evaluation of this region, and a detailed understanding of the normal anatomy of the supraclavicular fossa as seen on MR is important. We present a correlative study between highresolution MR images obtained with local coils and anatomic sections obtained with a cryomicrotome.

Arteriographic visualization of parenchymal striation in renal vein thrombosis is reported for the first time. The striations correspond to the location and orientation of the peritubular capillary beds of the renal cortex, which are in linear continuity with the vasa recta of the medulla. Opacification of these vascular structures in a cadaver kidney produced the same striation pattern. One possible physiologic explanation is that renal vein thrombosis causes elevated renal interstitial pressure which slows tubular urine flow. This altered intrarenal state prevents opacification of renal tubular structures while adjacent peritubular vascular structures are opacified, thereby producing a pattern of alternating striation.

Sacroiliitis is often difficult to diagnose with certainty using conventional radiographs and radionuclide scanning. Computed tomography was used to study the sacroiliac joints in 20 consecutive patients clinically suspected of having sacroiliitis on initial evaluation. Of these 20 patients, 17 fulfilled conventional clinical criteria for sacroiliitis; computed tomography demonstrated changes of sacroiliitis in 12 of these 17 patients. CT revealed no changes of sacroiliitis in the three patients who failed to meet conventional clinical criteria for sacroiliitis. Conventional radiography demonstrated diagnostic changes of sacroiliitis in only five patients. Seven patients with CT changes of sacroiliitis had equivocal or negative conventional films. CT therefore seems superior to conventional radiography in detecting sacroiliitis.

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.

The relative efficacies of different spin-echo pulse sequences at 1.5 T were evaluated in the detection of focal hepatic disease. Pulse sequences compared were spin-echo with a repetition time (TR) of 200 msec and echo time (TE) of 20 msec, with six excitations; TR = 300 msec, TE = 20 msec, with 16 excitations (T1-weighted sequences); and a double spin-echo with TR = 2500 and TE = 25 and 70, with two excitations (proton-density-weighted and T2-weighted pulse sequences, respectively). Respiratory-motion compensation, which involved a recording of the phase-encoding gradients (Exorcist), was used for the last two sequences. Spin-echo with TR = 2500 msec and TE = 70 msec was superior in lesion detection and contrast-to-noise ratio. The proton-density-weighted and T2-weighted sequences with respiratory compensation produced better artifact suppression than did the short TR, short TE T1-weighted sequence with temporal averaging. In contradistinction to prior results at 0.6 T, T2-weighted pulse sequences appear superior to T1-weighted pulse sequences with multiple excitations for both lesion detection and artifact suppression at 1.5 T.

Although progress has been made toward understanding retroperitoneal anatomy [1 -5], it is still difficult to reconcile certain abdominal CT findings with prevailing concepts about the developmental and adult anatomy of the retroperitoneal spaces. Our aims here are to (1) review current concepts about the compartmental anatomy of the retroperitoneum, (2) present CT findings that are difficult to explain on the basis of current notions about the retroperitoneal spaces, and (3) propose a hypothesis that may help clarify the developmental and subsequent anatomic divisions of the retropentoneum.

Venous-phase arteriography after celiac or superior mesenteric artery injection is the most common technique used to demonstrate portal venous anatomy, flow direction, and portal systemic shunts. Large-volume contrast material injections and intraarterial vasodilators or balloon occlusion technique are required for optimal examinations using film-screen recording. A technique for performing venous-phase arteriography with digital subtraction imaging after celiac and superior mesenteric artery injection is described. The major advantage of intraarterial digital subtraction technique in comparison to film-screen recording is sensitivity to intravascular iodine with a consequent reduction in contrast material load and examination time. Technical success is limited only by motion artifact and should approximate the 80%-90% figure achieved for intravenous digital subtraction angiography of the aortorenal vessels.

A study comparing ECG-gated and nongated acquisition for selective carotid digital subtraction arteriography was performed on 116 bifurcations in 63 patients. For ECG acquisition, three exposures (systole, early diastole, and late diastole) were obtained for each cardiac cycle. There was no significant difference in the frequency of plaque misregistration between gated (18%) and nongated (23%) acquisitions. In gated studies, the frequency of plaque misregistration was equivalent in systole, early diastole, and late diastole. Gated and nongated studies provided equivalent image quality for selective carotid digital subtraction angiographic studies.

Although obstructive jaundice is a common manifestation of cholangiocarcinoma, segmental bile duct obstruction is rare [1]. Recently, we encountered a patient with a soft-tissue mass in the common hepatic duct, asymmetric bile duct dilatation, and atrophy of the left hepatic lobe secondary to a slowly growing tumor. The computed tomographic (CT) appearance of lobar hepatic atrophy secondary to cholangiocarcinoma has not been reported previously to our knowledge.

CT examinations of four proven abdominal abscesses with enteric communications are reported. All the patients received oral contrast (3% Gastrografin solution). Three patients recieved rectal contrast. The patient who did not receive rectal contrast had a prior abdominoperineal resection. Contrast material was administered intravenously unless there was a contraindication or a suspected enteric vesical fistula. A representative case is described.