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Biomedical subjects

W D Middleton

Publications and source records attributed to W D Middleton.

At least 55 records · Page 3Linked to original sources
PubMed1992

Color Doppler sonography of ureteral jets in normal volunteers: importance of the relative specific gravity of urine in the ureter and bladder.

OBJECTIVE: Sonographic visualization of ureteral jets is a well-recognized phenomenon. In vitro studies have indicated that detection of fluid flow similar to ureteral jets depends on differences in density between the moving and the stationary fluid. This study was undertaken to determine if differences in density between ureteral urine and urine in the bladder could make a significant impact on the sonographic detectability of ureteral jets in vivo. SUBJECTS AND METHODS: Ten healthy volunteers were vigorously hydrated after an overnight fast. An initial color Doppler sonographic examination of ureteral jets was performed before voiding (while concentrated urine that had accumulated overnight was still in the bladder). A second examination was performed after two cycles of voiding and refilling the bladder (to ensure that dilute urine produced by the hydration was in the bladder). RESULTS: In all subjects, normal ureteral jets were readily identified on the initial examination. The difference in the estimated specific gravity between bladder urine and ureteral urine during the initial examination ranged from 0.002 to 0.016 (mean, 0.008). This was a statistically significant difference (p less than .05). On the second examination, ureteral jets were not detected from either ureter in any subject. The difference in the estimated specific gravity of bladder urine and ureteral urine during the second examination ranged from 0.000 to 0.002 (mean, 0.001). This was not a statistically significant difference (p greater than .05). There was no statistically significant difference in the diuresis rates throughout the course of the examinations. These ranged from 300 to 1218 ml/hr. CONCLUSION: These in vivo results support the hypothesis that detection of ureteral jets depends on density differences between ureteral and bladder urine. This is important clinically, because normal ureteral jets may be undetectable, despite adequate hydration and high rates of diuresis, if the patient is allowed to completely void and refill the bladder before the examination.

Adult↗
PubMed1992

Tubular ectasia within the mediastinum testis.

Eleven scrotal sonographic examinations showing a spectrum of findings within the mediastinum testis were collected over a 2 year period. Each case showed numerous small tubular or rounded anechoic structures within the mediastinum testis; often, the findings mimicked a hypoechoic mass. Findings were bilateral in eight of ten patients; one additional patient had only one testis because of orchiectomy. All patients had an associated extratesticular finding, in most cases a spermatocele. Tubular ectasia shares several features with testicular cysts and mechanisms of formation are postulated to be similar to those previously proposed for testicular cysts. Recognizing tubular ectasia is important to avoid unnecessary concern and potential surgery.

Aged↗
PubMed1992

Recent advances in sonography of the testis and scrotum.

Ultrasonography remains an accurate, rapid, and safe tool in the imaging of disorders of the testes and scrotum. The strengths of gray scale sonography lie in its ability to distinguish intratesticular from extratesticular processes. Improvements in resolution permit greater confidence in the characterization of lesions as representing simple fluid, complex fluid, or solid lesions. The addition of flow information by color Doppler ultrasonography and duplex Doppler ultrasonography represents the most exciting recent advancement, permitting even more diagnostic information in the evaluation of these patients.

Color↗
PubMed1992

Ultrasonography of the shoulder.

Shoulder sonography has been shown to be an effective noninvasive means of detecting rotator cuff tears and biceps tendon abnormalities. The examination requires careful attention to technique and a thorough knowledge of normal gross and sonographic anatomy. Rotator cuff tears generally cause a diffuse or focal decrease in the space between the humeral head and the deltoid muscle. Therefore, tears are easiest to detect by noting abnormally close apposition of the deltoid and humeral head.

Humans↗
PubMed1991

Correlation of testicular color Doppler ultrasonography, physical examination and venography in the detection of left varicoceles in men with infertility.

High resolution color Doppler ultrasound is a noninvasive means of simultaneously imaging and evaluating the blood flow to the testes. To define the ability of color Doppler ultrasound to detect clinically evident as well as subclinical varicoceles men referred to our urology division with oligospermia and infertility underwent spermatic vein venography of the left testis if there was physical examination and/or color Doppler ultrasound evidence of a varicocele. The detection of valvular incompetence on venography was considered diagnostic for a varicocele. Of 17 study patients physical examination detected 10 of 14 venographically evident varicoceles (71%), whereas color Doppler ultrasound detected 13 of 14 (93%). Of 5 patients with a normal physical examination but with color Doppler ultrasound evidence of a varicocele 4 had a confirmatory venogram, and 1 of 2 patients with a varicocele on physical examination and a normal Doppler ultrasound had a positive venogram. These data suggest that color Doppler ultrasound of the testis may more appropriately direct further invasive testing and therapy of infertile men than physical examination alone.

Humans↗
PubMed1991

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.

Epididymitis↗
PubMed1991

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.

Abscess↗
PubMed1991

Ureteral jets in healthy subjects and in patients with unilateral ureteral calculi: comparison with color Doppler US.

Color Doppler ultrasound was used to image the ureteral jets in 17 healthy subjects and 26 patients with ureteral calculi proved with intravenous urography. In patients with ureteral calculi, three patterns of ureteral jets were seen: no detectable urine flow from the symptomatic side (12 patients), low-level continuous flow from the symptomatic side (four patients), and periodic ureteral jets on the symptomatic side that were not significantly different from ureteral jets of healthy subjects (10 patients). Of the 12 patients with high-grade obstruction on urograms, 11 had ureteral jets significantly different from those of healthy subjects (either no detectable ureteral jets or continuous low-level jets on the symptomatic side). Only three of the 11 patients with low-grade obstruction or nonobstructing stones had ureteral jets that were different from those of healthy subjects. It is concluded that analysis of ureteral jets with color Doppler can enable detection and qualitative determination of the degree of ureteral obstruction in many patients with unilateral ureteral calculi.

Adult↗
PubMed1991

Laparoscopic cholecystectomy: evaluation with sonography.

To determine the normal postoperative appearance of gallstones in the common duct at ultrasound (US) examination, the significance of fluid collections after surgery, and the usefulness of routine postoperative scanning, US of the right upper quadrant was performed in 106 consecutive patients 24 hours after laparoscopic cholecystectomy. The location, volume, and appearance of fluid collections were recorded. The maximum diameter of the common duct was measured in all patients and compared with preoperative measurements in 58 patients. Small fluid collections were identified in the gallbladder fossa in 56 patients (53.0%). Fluid collections did not correlate with fever or white blood cell count. In 15 of 58 patients, the diameter of the common duct had increased on the postoperative scan. This did not correlate with alkaline phosphatase or bilirubin levels. One hundred one patients (95.3%) were discharged the day after surgery. Routine US performed the day after surgery did not alter management; the authors conclude that it is unwarranted in their group of patients.

Adult↗
PubMed1990

Prevalence of local venous thrombosis after transfemoral placement of a Bird's Nest vena caval filter.

Bird's Nest vena caval filters were placed in 63 patients over a 6-month period by means of a transfemoral (n = 62) or transjugular (n = 1) approach. To determine the prevalence of access-site thrombosis, compression color Doppler flow imaging was performed 1-11 days after the procedure in 48 patients without suspected or documented preexisting thrombus. Clinical follow-up was from 5 to 289 days (mean, 100 days). Findings at ultrasound (US) examination were normal in 38 patients, and all of these patients remained clinically asymptomatic. Nonocclusive thrombus was seen in nine patients, eight of whom remained asymptomatic. A single patient had an occlusive thrombus at US. This patient had leg swelling. Nonocclusive thrombus did not predispose patients to the development of clinically evident occlusive thrombosis. The authors conclude that the transfemoral placement of the Bird's Nest vena caval filter is associated with a low prevalence (2%) of femoral vein occlusion documented at US follow-up. This contrasts with results from a similarly designed study demonstrating a 17% prevalence after percutaneous Greenfield filter placement.

Adult↗
PubMed1990

Sonography of complications in pediatric renal allografts.

A total of 420 sonograms of renal transplants in 80 children were obtained because of decreased renal function or to establish a baseline after surgery. We describe normal anatomy of a renal transplant on sonograms, including duplex Doppler and color flow images, and a spectrum of complications. The complications are categorized as follows: parenchymal (drug toxicity rejection, acute tubular necrosis, infection), vascular (pseudoaneurysm, arteriovenous fistula, renal artery stenosis and occlusion), obstructive uropathy, and postoperative fluid collections.

Child↗
PubMed1990

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.

Acute Disease↗
PubMed1990

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.

Blood Flow Velocity↗