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Biomedical subjects

J M Rubin

Publications and source records attributed to J M Rubin.

At least 91 records · Page 5Linked to original sources
PubMed1994

Intrarenal arterial Doppler sonography in the detection of renal vein thrombosis of the native kidney.

OBJECTIVE: Previous studies of transplant kidneys and recent reports on native kidneys have suggested intrarenal arterial Doppler findings can be helpful in the noninvasive workup of renal vein thrombosis. We used arterial Doppler sonography to evaluate cases of possible acute renal vein thrombosis in native kidneys that had equivocal results on standard Doppler analysis of the renal vein. MATERIALS AND METHODS: Twenty native kidneys in 12 patients with clinical findings suggestive of acute renal vein thrombosis had Doppler studies of the main renal vein that failed to show normal flow. In all 20 kidneys, duplex Doppler study of arcuate/interlobar intrarenal arteries was done and the resistive index was determined. The Doppler findings were compared with subsequent findings on either renal venograms (n = 11) or MR images (n = 9), which served as the reference "gold" standards. RESULTS: The prevalence of renal vein thrombosis was 25% (5/20). Ten kidneys had very abnormal findings on arterial Doppler studies (absent or reversed end-diastolic flow), but only two of these were proved to have renal vein thrombosis. In six other kidneys, end-diastolic flow was identified but the resistive index was still elevated (> or = 0.70), and only one of these kidneys was proved to have renal vein thrombosis. Four kidneys had normal arterial Doppler studies, and 50% (two) of these were proved to have renal vein thrombosis. When absent or reversed end-diastolic flow was used as a sign of renal vein thrombosis, intrarenal arterial Doppler analysis had a sensitivity of 40% (2/5) and a specificity of 47% (7/15). CONCLUSION: Unlike the reported experience in transplanted kidneys, intrarenal arterial Doppler analysis is neither sensitive nor specific for renal vein thrombosis in native kidneys. An intrarenal arterial Doppler study with normal findings should not prevent further workup if Doppler findings in the renal vein are equivocal, nor should absent or reversed end-diastolic arterial signals be considered highly suggestive of renal vein thrombosis.

Female↗
PubMed1994

Detection of soft-tissue hyperemia: value of power Doppler sonography.

OBJECTIVE: Power Doppler sonography is a new technique that offers extended dynamic range over that provided by conventional color Doppler imaging, thereby facilitating measurement of tissue perfusion. We evaluated the efficacy of power Doppler sonography in depicting soft-tissue hyperemia in musculoskeletal inflammatory conditions. SUBJECTS AND METHODS: Twenty-three patients with predominantly unifocal musculoskeletal symptoms were evaluated with conventional gray-scale imaging and power Doppler sonography. The shoulder was evaluated in 14 patients, the elbow in three, and various other sites in six. For comparison purposes, the contralateral asymptomatic joint or site was examined in 17 cases. Fluid collections were aspirated in seven patients. RESULTS: Soft-tissue hyperemia was seen on power Doppler sonograms at the symptomatic site(s) in 22 of 23 cases studied, with an appearance ranging from frank tissue blush to large, isolated peritendinous/peribursal vessels. Findings associated with hyperemia included rotator cuff tendinitis and/or tear, bursitis, and symptomatic wrist ganglia. Findings on power Doppler sonograms were normal in one patient who had a small, sterile hip joint effusion, and findings on subsequent scintigrams, pelvic radiographs, and CT scans were normal. CONCLUSION: Power Doppler sonography consistently shows hyperperfusion associated with musculoskeletal inflammatory disease. As such, it represents a useful adjunct to gray-scale sonography in these settings, particularly as findings on conventional sonograms in inflammatory conditions can be nonspecific.

Adult↗
PubMed1994

Renal duplex Doppler ultrasonography: a noninvasive predictor of kidney dysfunction and hepatorenal failure in liver disease.

Hepatorenal failure, a well-recognized complication of established liver disease, is characterized by early renal hemodynamic changes (vasoconstriction) before clinically recognized kidney disease. This renal vasoconstriction (increased renal vascular resistance) should be detectable noninvasively by Doppler ultrasonography. We studied whether renal Doppler ultrasonography detects abnormalities in patients with nonazotemic liver disease and its prognostic value for subsequent kidney status. We observed by renal Doppler ultrasonography 180 patients who had liver disease without azotemia. A simple parameter, resistive index, was derived for each subject on the basis of Doppler waveform analysis. Traditional parameters used to assess patients with liver disease were also recorded at the time of Doppler ultrasonography. Subsequent kidney outcomes were kidney dysfunction (doubling of initial creatinine level to 1.5 mg/dl [133 mumol/L]) or more and the presence or absence of the hepatorenal syndrome. Abnormal results of Doppler examinations (elevated resistive index) were seen in 76 (42%) of the 180 patients. Kidney dysfunction developed in 55% (42/76) of the patients with an elevated resistive index and 6% (6/104) of those with normal results of Doppler study (p < 0.00005). Hepatorenal syndrome developed in 26% (20/76) of subjects with an elevated resistive index and 1% (1/104) of those with a normal resistive index (p < 0.00005). Cox regression analysis identified resistive index as a significant independent predictor of subsequent hepatorenal syndrome (p < 0.00005) and kidney dysfunction (p < 0.00005). Renal duplex Doppler ultrasonography can noninvasively identify a subgroup of nonazotemic patients with liver disease that is at significantly higher risk for subsequent development of kidney dysfunction and the hepatorenal syndrome.

Adolescent↗
PubMed1993

Comparisons of dynamic infusion and delayed computed tomography, intraoperative ultrasound, and palpation in the diagnosis of liver metastases.

The purpose of this study was to determine whether delayed computed tomography (DCT) of the liver would more accurately detect hepatic malignancy when compared with bolus contrast-enhanced dynamic computed tomography (BCDCT). Fifty-one patients who required operation for intra-abdominal malignancy (92% with colorectal cancers) underwent preoperative BCDCT followed by DCT. At operation, palpation and intraoperative ultrasound (IOUS) examination of the liver were performed for localization and biopsy of tumor nodules. The standard for diagnosis was defined for this study as the combined results of IOUS, palpation, and biopsy. The sensitivities of BCDCT and DCT for hepatic metastases were 50% and 54%, respectively, with a corresponding specificity of 72% for each. DCT demonstrated no significant improvement over BCDCT in the detection of individual hepatic lesions. The sensitivity of palpation for the detection of metastases was 82%, equal to that of IOUS. Both palpation and IOUS were significantly superior to BCDCT or DCT in excluding false-positive and false-negative results (p < 0.001). IOUS failed to identify surface lesions less than 1.0 cm in diameter (sensitivity: 40%). Conversely, palpation was limited in the detection of subsurface tumors less than 1.0 cm in diameter (sensitivity: 33%). Combined IOUS and palpation were significantly more accurate in the detection of hepatic metastases than any single modality that was evaluated (p < 0.001).

Colorectal Neoplasms↗
PubMed1993

Intramuscular methylprednisolone acetate for the prevention of relapse in acute asthma.

STUDY OBJECTIVE: To examine the hypothesis that an IM long-acting steroid injection will decrease the relapse rate of asthma patients. DESIGN: A randomized, single-blind, placebo-controlled trial. SETTING: The emergency department of an urban academic medical center. TYPE OF PARTICIPANTS: Acute asthma patients aged 18 to 45 years who were treated successfully in the ED. INTERVENTIONS: Participants received either IM saline placebo or 240 mg methylprednisolone acetate suspension at the time of discharge. MEASUREMENTS AND MAIN OUTCOME: Relapse, defined as the need to seek nonroutine medical care for asthma within seven days of discharge, was the main outcome measure. Of 70 patients entered, 56 (80%) completed follow-up, including 30 in the steroid group and 26 in the placebo group. The groups had similar characteristics and peak expiratory flow values on arrival and at discharge. Relapse occurred in two steroid patients (6.7%) and eight placebo recipients (30.8%) (P < .05). There was one death in the placebo group. Reported side effects were similar. CONCLUSION: IM long-acting steroids reduced the rate of relapse in patients with acute asthma.

Adolescent↗
PubMed1993

Acute renal obstruction: evaluation with intrarenal duplex Doppler and conventional US.

To evaluate duplex Doppler ultrasound (US) in acute renal obstruction, bilateral intrarenal Doppler US was performed in 23 patients with unilateral renal obstruction (proved by means of intravenous urography) of 36 hours duration or less. A mean renal resistive index (RI) was calculated for each obstructed and normal contralateral kidney and compared with findings on conventional US scans. The mean RI in the obstructed kidneys was elevated (.77 +/- .07 [standard deviation]) and was higher than the mean RI in the normal contralateral kidney (.60 +/- .04) (P < .001). RIs in the obstructed kidneys were as follows: .75 or greater in 15 kidneys, .70-.74 (mild RI elevation) in five kidneys (but > or = .10 higher than the RI in the normal contralateral kidney), and less than .70 in three kidneys (two of these three patients had pyelosinus extravasation and one patient had clinical obstruction for only 4-5 hours). RI elevation occurred before collecting-system dilatation in four patients (17%). RI elevation occurs by 6 hours of clinical acute renal obstruction and may precede pyelocaliectasis. Renal duplex Doppler US contributes useful clinical information, especially when US is the first modality used to evaluate acute renal colic.

Acute Disease↗
PubMed1993

Heterozygous familial hypercholesterolemia: detection of xanthomas in the Achilles tendon with US.

Prospective sonographic evaluation of 44 Achilles tendons in 22 patients with heterozygous familial hypercholesterolemia (FH) was performed with linear-array transducers with high frequency and high resolution. Intratendinous hypoechoic regions believed to represent xanthomas, ranging from single hypoechoic nodules to diffusely enlarged tendons that were heterogeneously hypoechoic, were seen in 40 of the 44 tendons (91%) and 21 of the 22 patients (95%). In addition, focal xanthomas were seen in two of three patients whose Achilles tendons were either normal or questionably abnormal at palpation. The direct visualization of xanthomas in most of these patients contrasts with findings from previously published studies, in which sonographically detected involvement was based on secondary tendon enlargement alone. The improved sonographic visualization of tendon xanthomas in FH, rather than the secondary tendon enlargement caused by them, therefore, suggests a new role for ultrasound in the early diagnosis and follow-up of these cases.

Achilles Tendon↗
PubMed1993

Assessment of internal ureteral stent patency in patients with pyelocaliectasis: value of renal duplex sonography.

OBJECTIVE: The purpose of this study was to evaluate duplex Doppler sonography in the assessment of internal ureteral stent patency. SUBJECTS AND METHODS: Thirty-three kidneys with pyelocaliectasis and an internal stent were studied with Doppler sonography and conventional sonography. Stent patency was proved by subsequent contrast-enhanced studies, direct inspection of the stent after removal, or clinical follow-up. RESULTS: The 11 kidneys with stent dysfunction had a significantly higher mean resistive index (0.78 +/- 0.08) than the 22 kidneys with patent stents (resistive index = 0.62 +/- 0.05) (p < .001). Eighty-two percent (9/11) of kidneys with occluded stents had elevated resistive indexes. The two occluded stents with normal resistive indexes were found in kidneys without significant obstruction before stent placement. Ninety-one percent (20/22) of patent stents were associated with a resistive index of less than 0.70. In the two cases of falsely elevated Doppler studies, the resistive index was obtained only 24-36 hr after placement of the stent; however, the resistive index was at least 10% less than that before stent placement. No significant correlation existed between degree of pyelocaliectasis shown on real-time sonography and stent status. CONCLUSION: In the presence of pyelocaliectasis after placement of an internal ureteral stent, intrarenal Doppler sonography can be used to accurately distinguish between patency and obstruction. Real-time sonographic findings (degree of pyelocaliectasis) are not useful in this clinical situation.

Adult↗
PubMed1993

Renal duplex Doppler sonography in asymptomatic women during pregnancy.

The purpose of this study was to establish the normal range of the renal RI in pregnant women. Maternal renal RIs were calculated in 61 asymptomatic pregnant patients with at least unilateral pyelocaliectasis. A mean RI was calculated for each kidney. Overall, the mean RI was 0.61 +/- 0.05. The renal RI was > or = 0.70 in 4% (5/121) of kidneys with no statistically significant difference between the mean right (0.62 +/- 0.06) and left (0.60 +/- 0.04) kidney RIs. There was no correlation between trimester of pregnancy or degree of pyelocaliectasis and RI.

Blood Flow Velocity↗
PubMed1992

Usefulness of an acoustic edge artifact in assessment of the Ilizarov corticotomy interval.

Thirty-three ultrasound examinations of the corticotomy interval of patients undergoing Ilizarov procedures were retrospectively evaluated for the presence or absence of an acoustic edge artifact. This artifact, consisting of a fine anechoic band, has been previously described in phantom models and is presumed to be due to phase cancellation effects. We demonstrated this artifact in 8 of 33 examinations. The artifact proved helpful in identifying the location of the corticotomy margin, even when this margin was obscured by the presence of developing periosteal new bone. Attention to technical factors is, however, important. We believe that this artifact may have a useful role in the routine monitoring of the Ilizarov patient.

Adolescent↗
PubMed1992

Quantitative assessment of cartilage surface roughness in osteoarthritis using high frequency ultrasound.

Osteoarthritis (OA) is a common disease which affects nearly 50% of people over age 60. Histologic evaluation suggests that fibrillations approximately 20-150 microns are among the earliest changes in the articular cartilage. We propose a technique to quantify these surface fibrillatory changes in osteoarthritic articular cartilage by considering the angular distribution of the envelope-detected backscattered pressure field from an incident 30-MHz focused transducer. The angular distribution of the scattered acoustic field from an inosonifying source will directly relate to the distribution of surface fibrillatory changes. Data are presented for three different grades (400, 500 and 600 grit) of commercially available emory paper and three samples of osteoarthritic femoral head articular cartilage, which were visually assessed as having smooth, intermediate and rough surfaces, respectively. Our preliminary results indicate a probable monotonic relationship between articular cartilage roughening and the degree of broadening in the angle-dependent pressure amplitude. When applied to the emory paper, the technique indicates sensitivity to differences as small as approximately 5-10 microns in mean roughness. This procedure may provide an extremely sensitive and reproducible means of quantifying and following the cartilage changes observed in early osteoarthritis.

Cartilage, Articular↗
PubMed1992

Laminar submerged jets by color Doppler ultrasound. A model of the ureteral jet phenomenon.

RATIONALE AND OBJECTIVES: The authors developed and tested a technique to noninvasively measure ureterovesical junction (UVJ) pressure gradients. Such a technique could be used to evaluate ureteral reflux and obstruction. METHODS: Color Doppler ultrasound measurements of an in vitro model of the ureteral jet were performed. RESULTS: The authors show that the orificial rate of momentum transfer of the ureteral jet (from which the intraluminal pressure in the ureter can be calculated) can be determined to within 45% to 94% of its true value depending primarily on the flow sensitivity of the color flow imager. Marked improvement in the momentum calculation (> 80%) is achieved when a low-flow sensitivity is used. CONCLUSION: Such noninvasive measurements could replace more invasive techniques (eg, the Whitaker test or cystoscopy with or without ureteral cannulation), which seriously perturb the system of interest.

Humans↗
PubMed1992

Renal dysfunction in hepatic disease: early identification with renal duplex Doppler US in patients who undergo liver transplantation.

To improve early detection of renal dysfunction in patients who undergo liver transplantation, a prospective study was performed with intrarenal duplex Doppler sonography before and after liver transplantation in 42 patients. The duplex Doppler findings were compared with multiple clinical and laboratory findings; patients were grouped on the basis of preoperative renal resistive index (RI) and serum creatinine level. The mean initial renal RI was elevated (.73 +/- .07 [standard deviation]); after transplantation, it was lower (.60 +/- .06) (P less than .001). Thirty-six patients had a normal serum creatinine level at the preoperative Doppler examination. Patients with an elevated renal RI (n = 19) had a greater chance of subsequent renal dysfunction (P less than .001), hemodialysis (P less than .01), longer stays in the intensive care unit (P less than .05), and longer hospital stays after surgery (P less than .05) than those with a normal renal RI (n = 17). In 34 patients the RI fell 10% or more after surgery and none died, whereas five of eight patients (62%) whose RI fell less than 10% died. Doppler analysis enabled identification of patients without azotemia whose course of disease before and after surgery was similar to that of patients with clinically recognized renal disease.

Adolescent↗
PubMed1992

Age dependency of the renal resistive index in healthy children.

It has recently been suggested that the resistive index (RI) in native kidneys of healthy children is age dependent; however, this relationship has not been completely defined or explained. In 110 kidneys in 71 healthy children aged newborn to 11 years, RIs were determined from peripheral sites (presumed to be arcuate, cortical, or distal interlobar arteries). The authors found the normal renal RI (the mean RI in each kidney) to be age dependent. The renal RI in children is commonly elevated above the upper normal limit in adults (0.70) in the 1st year of life, and the overall trend shows a decrease with age. From 4 years on, the likelihood is low (2% probability) that the RI is above 0.70. Variability of the renal RI from individual to individual was most marked in the first 6 months of life, with 51% (19 of 37) of these kidneys having an RI that would be considered abnormal by adult standards. It is concluded that the normal renal RI is age dependent, with an overall decreasing trend with increasing age. This age dependency of the renal RI and, hence, of the renal vascular resistance might be dependent on levels of active renin, as the maturational profile of the renal RI more closely parallels that of active renin than those of other renal functional parameters.

Aging↗
PubMed1992

Ruptured gel-filled silicone breast implants: sonographic findings in 19 cases.

OBJECTIVE: The purpose of this study was to describe and illustrate the sonographic appearances of 19 ruptured silicone gel breast implants. MATERIALS AND METHODS: We retrospectively reviewed the sonograms of 16 patients with 19 ruptured silicone gel implants from two institutions. The ruptured implant was confirmed at surgery in 17 cases and by mammographic and clinical findings of a ruptured implant combined with biopsy findings of a silicone granuloma in two cases. Breast sonograms were available for review in all patients. The clinical presentation of each patient was recorded. The sonograms and mammograms were reviewed, and the findings were correlated with the surgical findings. In 16 of the 19 ruptured implants, mammographic findings suggested rupture, including lobulation of the contour of the implant and/or silicone extrusion into the breast parenchyma or axilla. In two ruptured implants, mammographic findings were normal, and in one case, no mammogram was available. In those three patients, palpable masses and clinical findings were suggestive of rupture. RESULTS: Sonography showed a unique echogenic appearance called echo-dense noise, in 17 of the 19 ruptured implants; in 10 of the 17, sonograms showed hypoechoic masses of extruded silicone also. In two ruptured implants, sonograms showed only the hypoechoic masses of extruded silicone gel. CONCLUSION: Our experience suggests that echogenic noise is a unique sonographic sign of ruptured silicone gel breast implants and may be caused by phase aberration related to the speed of sound being slower in silicone than in soft tissue.

Equipment Failure↗