Hyperechoic renal cell carcinomas: increase in detection at US.

Recent reports have indicated that hyperechoic renal cell carcinomas (RCCAs) are more frequent among small cancers and that small cancers are being detected more frequently. To determine whether these trends have resulted in a change in the frequency of detection of hyperechoic RCCA and, in particular, in the frequency of RCCA mimicking angiomyolipomas (AMLs), the sonographic features of 90 pathologically proved RCCAs in 82 patients were retrospectively reviewed and correlated with tumor size. Tumor echogenicity was compared with that of normal renal parenchyma and classified as hypoechoic, isoechoic, slightly hyperechoic, or markedly hyperechoic. Thirty-one tumors were 3 cm in diameter or less, and 59 were larger than 3 cm. Ten (32%) of the tumors 3 cm in diameter or less were markedly hyperechoic and mimicked AMLs, whereas only one (2%) of the tumors larger than 3 cm had this appearance (P < .001). Eleven of the 90 tumors (12%) were markedly hyperechoic. Twenty-four (77%) of the small tumors were either slightly or markedly hyperechoic, compared with 19 (32%) of the larger tumors (P < .001). Because of the increased detection of small RCCAs in recent years, the number of hyperechoic cancers and the number of cancers mimicking AMLs have increased.

Morphologic and hemodynamic findings at sonography before and after creation of a transjugular intrahepatic portosystemic shunt.

OBJECTIVE: The purpose of this study was to describe the morphologic and hemodynamic findings in the hepatic vasculature before and immediately after creation of a transjugular intrahepatic portosystemic shunt. SUBJECTS AND METHODS: We used gray-scale, duplex, and color Doppler sonography to prospectively examine 25 patients before and after percutaneous placement of a stent to create a transjugular intrahepatic portosystemic shunt. Patency and direction of flow were determined in the stent and in the main, right, and left portal veins. Flow velocity was measured in the stent and in the main portal vein. RESULTS: In all patients, the stent was easily identified as connecting branches of the portal and hepatic veins. Three thrombosed stents were correctly detected sonographically. One stent that was thought to be thrombosed at sonography was found to be patent at angiography. Flow velocities in the patent stents ranged from 73 to 185 cm/sec (mean, 130 +/- 33 cm/sec). Mean peak velocities in the main portal vein were 20 cm/sec before stent placement and 38 cm/sec after stent placement (p < .002). In 14 patients, flow direction in the left or right portal vein was hepatofugal after the stent was placed. In two of these 14 patients, long-term follow-up showed subsequent conversion of flow in the portal vein branches from hepatofugal to hepatopetal. One of these two patients had a thrombosed stent and the other had a hepatic vein stenosis above the stent. The second patient also had a proven decrease in flow velocity in the stent at the time of stenosis. CONCLUSION: We conclude that high flow velocities are expected in the main portal vein and in the stent immediately after the shunt is created and that flow in portal vein branches is usually hepatofugal. We recommend sonography soon after the shunt is created, so that baseline flow velocity in the stent and flow direction in portal vein branches can be established, because a subsequent decrease in flow velocity in the stent or a change in direction of flow in a portal branch may indicate stent malfunction.

Testicular tumors: findings with color Doppler US.

A study of 28 patients with surgically proved testicular tumors was performed to determine the appearance at color Doppler ultrasound (US) scanning. There was a general correlation of tumor size and vascularity. Twenty of 21 (95%) tumors larger than 1.6 cm were hypervascular. Six of seven (86%) tumors smaller than 1.6 cm were hypovascular. One small, 1.1-cm-diameter seminoma was hypervascular, and one 2.8-cm-diameter seminoma was hypovascular. The histologic findings of the tumor did not correlate with the vascularity of the lesion as seen at color Doppler US. Resistive indexes ranged from .476 to 1.0 (mean, 0.70). Peak systolic velocities ranged from 8.4 cm/sec to 64.9 cm/sec (mean, 9.8 cm/sec). Venous flow was detected in eight tumors. The gray-scale findings, as well as history and physical examination findings, correctly suggested a neoplasm in all cases. The findings at color Doppler US were prospectively interpreted as indicative of neoplasm in 27 cases and as indicative of inflammation in one case. The authors conclude that color Doppler US scanning has only a limited role in the evaluation of testicular tumors.

Color Doppler US of the scrotum.

Color Doppler ultrasonography (US) is an increasingly important tool in the evaluation of the scrotum, especially in acute scrotal disorders. With this modality, arterial flow is readily detected in the normal spermatic cord and testis but is not seen in the epididymis; venous flow is not seen anywhere in the normal scrotum. Scrotal inflammatory lesions appear as hypervascularity of the epididymis or testis, even though gray-scale findings may be normal or nonspecific. Testicular torsion is demonstrated by an absence or marked decrease in the number of visible vessels. Small tumors (less than 1.5 cm) are hypovascular, and larger tumors (greater than 1.5 cm) are hypervascular. The modality also demonstrates Valsalva maneuver-induced venous flow augmentation in varicoceles and altered flow in testicular tumors. Color Doppler US allows for evaluation of morphologic findings and perfusion and enables accurate diagnosis of most scrotal disorders.

Scrotal inflammatory disease: color Doppler US findings.

A study of 45 patients with 51 cases of hemiscrotal inflammatory disease was done to determine the color Doppler ultrasonographic appearance of scrotal inflammatory disorders. The diagnosis was ultimately established by means of appropriate response to antibiotic treatment (47 cases) or surgery (four cases). In all cases, there was evidence of hyperemia: an increased number and concentration of detectable vessels in the affected portion of the scrotum. In 17 cases, the gray scale images were normal, and the only evidence of inflammation was the presence of hypervascularity. Abnormally decreased epididymal vascular resistance was detected in 14 cases of epididymitis; abnormally decreased testicular vascular resistance was detected in six cases of orchitis. Spontaneous venous flow was present in 18 patients. The authors conclude that color Doppler can demonstrate the hyperemic response to scrotal inflammatory disease and that, in the proper clinical setting, it can supplement the gray scale findings and increase diagnostic confidence.

Potential for localized, adjustable deep heating in soft-tissue environments with a 30-beam ultrasonic hyperthermia system.

Initial heating rates (degrees C/min) along parallel tracks at depths of 1-14 cm in a static, muscle-like phantom were determined from time-temperature profiles obtained with 'Helios', a 30-beam ultrasonic hyperthermia system developed by Varian Associates. Data were taken at a single operating frequency of 556 kHz, for different sets of focal plane ring diameters of the four-ring array applicator, different levels of transducer driving power and two different focal plane depths, 6 cm and 9 cm. In each experiment, at each point of temperature measurement, analysis of temperature versus time data over a 2 min heating interval permitted separation of the desired phantom heating from artefactual heating resulting primarily from absorption of transverse (shear) waves produced at phantom-metal probe catheter interfaces. The results of the studies conducted suggest that in a non-translating carriage mode, Helios can produce axially and laterally localized deep heating in soft tissues for tissue volumes of lateral dimension up to a minimum of 4 cm and tissue depths of at least 11 cm. The results obtained also suggest that Helios can produce laterally localized heating to tissue depths of at least 11 cm without excessive heating of superficial soft-tissue layers, for tissue volumes of lateral dimension up to a minimum of 8 cm. The methodology used in the phantom studies was applied to the production of localized heating in the right lobe of the liver of adult pigs. Temperature versus time profiles obtained in the in vivo studies indicated that, for the set of system parameters employed, concentration of ultrasonic power at greater depths in the liver (e.g. 10.5 cm versus 5 cm) could be achieved, suggesting that Helios should be able to produce localized heating of targeted hepatic volumes when its operating parameters are selected in accordance with effective treatment planning techniques.

Acute scrotal disorders: prospective comparison of color Doppler US and testicular scintigraphy.

Color Doppler ultrasonography (US) and testicular scintigraphy were used prospectively to evaluate 28 patients with acute scrotal pain. The results of these imaging studies were correlated with final diagnoses established by means of surgery or clinical follow-up. In all patients, testicular torsion was considered to be a possible diagnosis based on findings from the initial clinical evaluation. Findings from surgery confirmed testicular torsion in seven patients. All cases were correctly diagnosed with color Doppler US. Scintigraphy enabled correct diagnosis of six, but findings were false-negative in one patient with 180 degrees torsion. One patient had a surgically confirmed scrotal abscess that was correctly diagnosed with both color Doppler US and scintigraphy. Findings from clinical follow-up in the remaining 20 patients were consistent with epididymitis, orchitis, or torsion of an appendix testis. There were no false-positive diagnoses of testicular torsion by means of either color Doppler US or scintigraphy in any of these 20 patients. Color Doppler US is at least as accurate as testicular scintigraphy and can function as an effective means of evaluating patients with suspected testicular torsion.

The carotid ghost. A color Doppler ultrasound duplication artifact.

Color Doppler ultrasound examinations of the neck frequently demonstrate an artifactual region of color assignment deep to the common carotid artery that simulates blood flow in deep cervical arteries. Based on analysis of imaging performed on 10 normal volunteers, it was shown that the pulsed Doppler waveform originating from the artifact was identical to that of the common carotid artery. It was also shown that the artifact was always located deep to the common carotid artery regardless of location and positioning of the transducer. In vitro modeling using a flow phantom confirmed that the appearance was artifactual in nature. The mechanism of production most likely is related to a mirroring phenomenon at the deep wall of the common carotid artery.

Renal duplication artifact in US imaging.

To determine the appearance of artifactual renal duplication in ultrasound (US) imaging, the authors analyzed 22 examples of such duplication in 20 patients. The artifact appeared as a duplication of the collecting system in 18, as a suprarenal mass in three, and as upper-pole cortical thickening in one. It occurred in the left kidney in 15 patients, in the right kidney in three, and bilaterally in two. To determine the frequency of the artifact, 50 additional patients were scanned. It was identified in eight of these patients. Imaging characteristics and the results of in vitro modeling proved the artifact was due to sound beam refraction between the lower pole of the spleen or liver and adjacent fat. This artifact is much more common in the left kidney and occurs more frequently in obese patients. Knowledge of the appearance and cause of this artifact should help radiologists avoid diagnostic errors.

Perivascular color artifact: pathologic significance and appearance on color Doppler US images.

A distinctive type of artifactual extravascular assignment of color was identified in 49 color Doppler ultrasound (US) examinations in 43 patients. This artifact appeared as a random localized mixture of red and blue assigned to perivascular soft tissues; the artifact varied with the cardiac cycle, being most prominent in systole and absent or less prominent in diastole. The artifact was seen in 26 patients (32 examinations) at an anastomotic site or stenotic lesion associated with surgically created arteriovenous fistulas for hemodialysis. It was also observed in ten patients with accidental iatrogenic arteriovenous fistulas (renal transplant [n = 6], femoral artery [n = 3], and iliac artery [n = 1]), five with stenotic arteries not associated with arteriovenous fistulas, and two with arterial aneurysms. The authors believe this artifact reflects perivascular tissue vibration caused by turbulent intravascular blood flow. If properly recognized and accurately interpreted, the artifact can be a valuable color Doppler US sign of underlying vascular abnormality.

Testicular ischemia: color Doppler sonographic findings in five patients.

We studied the findings on color Doppler sonography in five men with testicular ischemia (three with acute testicular torsion and two with testicular infarcts after herniorrhaphies). In all five cases, no intratesticular blood flow was identified on the symptomatic side, while normal blood flow was evident on the opposite side. In the three cases of acute torsion, no gray scale sonographic abnormalities were seen, and in the two cases of postoperative infarction, the abnormalities were nonspecific. These findings suggest that color Doppler sonography can be used to show decreased blood flow in cases of acute testicular ischemia and that it may have a role in evaluating patients with suspected testicular torsion.

Postbiopsy renal transplant arteriovenous fistulas: color Doppler US characteristics.

Color Doppler ultrasound (US) with point-spectral analysis was performed on eight patients with postbiopsy renal transplant arteriovenous fistulas. Waveform analysis of the supplying artery documented decreased resistive indices in all cases and increased flow velocities in seven. The peak-systolic flow velocity in the arteries supplying the fistulas ranged from 55 to 180 cm/sec (mean, 92 cm/sec), while the range in normal arteries was 20-52 cm/sec (mean, 32 cm/sec). The resistive indices of the arteries supplying the fistulas ranged from 0.31 to 0.50 (mean, 0.45), while the resistive indices of the normal arteries ranged from 0.60 to 0.92 (mean, 0.74). Arterialization of the venous waveform from the draining vein was also documented in all cases. In six cases, the increased flow velocities resulted in increased color saturation toward white in the supplying artery (n = 2) or in both the artery and the draining vein (n = 4), which was detectable on the realtime image. In six cases, flow turbulence resulted in localized tissue vibration, which appeared as random color assignment in extravascular renal parenchyma adjacent to the fistula. Knowledge of these imaging and Doppler characteristics should aid in the identification of renal transplant arteriovenous fistulas with color Doppler US.

Color Doppler sonography of hemodialysis vascular access: comparison with angiography.

This study was performed to define the color Doppler sonographic appearance of normal and abnormal hemodialysis vascular access and to compare color Doppler sonography with angiography. Twenty-eight patients (nine with Brescia-Cimino fistulas and 19 with synthetic grafts) were imaged with digital subtraction angiography and color Doppler sonography. The examinations were interpreted independently and then interpreted together to determine the accuracy of the two methods. With angiography as the gold standard, color Doppler sonography correctly identified 20 of 23 stenosed vessels, three of four occluded vessels, four of four thrombosed vessels, and 18 of 19 pseudoaneurysms. Overall, color Doppler sonography correctly identified all lesions that were seen angiographically in 16 of 19 patients with synthetic grafts and in four of nine patients with Brescia-Cimino fistulas. Five asymptomatic arterial steals were detected sonographically. One of these was identified with angiography. Color Doppler sonography is an adequate means of imaging suspected complications of hemodialysis vascular access, and it should be used in selected patients. However, digital subtraction angiography is more sensitive and should be the initial imaging technique for most of these patients.

Color Doppler ultrasound of the normal testis.

Color Doppler ultrasound with point spectral analysis was performed on 30 testes of 15 asymptomatic volunteers. Intratesticular arteries and testicular capsular arteries were imaged in all 30 cases. Waveforms from these vessels were similar and consistently showed a low-impedance pattern with high levels of diastolic flow. This reflects the low vascular resistance of the testis. Supratesticular arteries were also identified in all 30 cases. In addition to the low-impedance-type waveforms from the testicular artery, waveforms obtained in the supratesticular region also originated from the deferential and/or cremasteric arteries. This resulted in some waveforms with high-impedance patterns, reflecting the high vascular resistance of the epididymis and peritesticular tissues. We believe that color Doppler ultrasound is capable of reliably showing the normal testicular arterial anatomy by imaging intraarterial blood flow. Knowledge of the normal color Doppler appearance and waveform characteristics of the testicular artery should aid in diagnosing scrotal conditions that alter blood flow.

Diaphragmatic discontinuity associated with perihepatic ascites: a sonographic refractive artifact.

Apparent discontinuity in the diaphragm frequently is seen in sonograms of the right upper quadrant in patients with perihepatic ascites. Using a fresh cadaveric liver and a linear reflector to simulate the diaphragm, we performed in vitro analysis and confirmed that the appearance of the diaphragm was artifactual; this was due to refraction of the sound beam at the interface between the liver and ascites. Knowledge of the typical sonographic appearance and location of this artifact should prevent diagnostic errors.

Pitfalls of rotator cuff sonography.

Experience with rotator cuff sonography in 106 patients was analyzed to identify the causes of scan misinterpretation. Possible interpretive errors may be classified into four categories: those from failure to recognize normal anatomy, those caused by soft-tissue abnormalities, those caused by bony abnormalities, and those caused by technical limitations of the study. Errors in recognition of normal anatomy are easily overcome by experience and comparison to the normal, contralateral rotator cuff. Errors resulting from soft-tissue abnormalities were seen in two patients with calcific tendinitis simulating rotator cuff tears. Problems in interpretation resulting from fractures in two patients and inferior glenohumeral subluxation in two other patients could have been avoided by review of the plain films before performing sonography. The major technical limitation of the study arises from the inability to image the rotator cuff beneath the acromion. Fortunately, rotator cuff tears are rarely isolated in this location, and passive maneuvers often allow otherwise hidden parts of the cuff to be imaged.

High resolution sonography in diagnosing testicular neoplasms: clinical significance of false positive scans.

We describe the use of high resolution real-time ultrasound to evaluate scrotal masses. From August 1980 to September 1984, 249 patients underwent scrotal ultrasound using high resolution real-time scanners with 10 mHz. transducers to evaluate scrotal abnormalities. The ultrasound diagnosis was consistent with a testicular neoplasm in 20 patients. Pathological and surgical confirmation was available in all 20 patients. Only 10 of 20 patients had malignant tumors, whereas 10 had benign lesions (false positive rate of 50 per cent). Testicular lesions producing false positive studies were principally hypoechoic in 8 patients and hyperechoic in 2. Testicular neoplasms characteristically were hypoechoic with or without focal hyperechoic areas. There was 1 false negative ultrasound study. Our results suggest that radical orchiectomy should not be performed indiscriminately in all patients with testicular lesions that are sonographically suspicious for neoplasm. In selected cases with hyperechoic sonographic features associated frequently with benign testis lesions open testicular biopsy and a testis-sparing operation may be indicated.

US of the biceps tendon apparatus.

High-resolution real-time sonography of the biceps tendon was performed on 80 patients referred for shoulder arthrography. The arthrograms and sonograms were compared at the levels of the biceps tendon groove and distal tendon. Sonography and arthrography were equally successful in facilitating the evaluation of the bony configuration of the biceps tendon groove, but sonography gave a superior image of the biceps tendon within the groove. In 16 patients, biceps tendon sheath effusions or swelling was detected using sonography; 15 of these patients had associated pathologic conditions elsewhere in the joint. Arthrograms did not disclose a biceps tendon or sheath abnormality in any of these patients. We conclude that sonography could be the imaging method of choice in patients with suspected biceps tendon lesions and that the presence of a biceps tendon or sheath abnormality indicates an increased likelihood of abnormalities elsewhere in the joint.

The spectrum of sonographic findings in infantile polycystic kidney disease with urographic and clinical correlations.

We evaluated nine patients, age 1 day to 17 years, having infantile polycystic kidney disease (IPKD). Using modern scanners with 5-MHz transducers we have observed two previously unemphasized sonographic (US) findings, a peripheral zone of normally echogenic cortex (five patients), and mild caliectasis (two patients). Our data suggest that IPKD is a more heterogeneous condition clinically and sonographically than generally appreciated and that presence of a thick normally echogenic renal cortex is a good predictor of concurrent normal renal function and prolonged survival.

Sonographic detection of rotator cuff tears.

Thirty-nine consecutive patients referred for shoulder arthrography underwent shoulder sonography to determine the ability of sonography to detect rotator cuff tears. Fifteen patients had arthrographically proven rotator cuff tears. Of these, 14 were detected by sonography, for a sensitivity of 93%. The three sonographic criteria indicative of rotator cuff tear were (1) discontinuity in the normal homogeneous echogenicity of the rotator cuff; (2) replacement of the normal homogeneous echogenicity by a central echogenic band; and (3) nonvisualization of the cuff. Twenty patients had normal sonographic examinations, 19 of which were normal by arthrography. Therefore, the predictive value of a negative sonogram was 95%. On the basis of these findings, sonography can provide a noninvasive means of screening patients with suspected rotator cuff tears.