Monitoring renal allograft rejection with duplex sonography

Thirty-six renal allograft recipients were monitored by serial duplex Doppler ultrasound studies post-transplant and during early rejection. A separate reproducibility study demonstrated no significant inter- or intra-operator variability in measurements of resistive index of an interlobar artery (RI) (2.1% [1.5%] and 3.2% [2.3%] respectively, mean [standard error] of coefficients of variance). Twenty-one patients had rejection within 3 weeks of transplantation. These grafts showed greater overall rises in the RI, from day 2 to day 5 post-transplant, than the grafts which had no rejection. Eleven of the 21 patients required more than one course of methyl-prednisolone for persistent or recurring rejection. These grafts had higher RI on the day rejection was diagnosed (81 [7.3], median [interquartile range]) compared with the remaining 10 patients (68.6 [8.7]). The 11 grafts with persistent rejection had higher RI (p less than 0.005, Mann-Whitney U-test) on day 2 post-transplant (76 [3.9]) compared with the 10 grafts successfully treated with a single course of methyl-prednisolone (63.2 [10.9]). This study demonstrates that grafts with an RI of greater than 70 on day 2 post-transplant are likely to have rejection requiring additional treatment (sensitivity--100%, specificity--80%). These patients may be candidates for earlier or alternative anti-rejection therapy.     

Interpretation of duplex Doppler ultrasound in renal transplants in the early postoperative period

A prospective study of duplex Doppler ultrasound in 29 renaltransplants was undertaken to determine how to interpret Dopplerfindings in the immediate postoperative period. The study includedintraoperative pulsed Doppler recordings from grafts immediatelyfollowing release of vessel clamps. Subsequent follow-up studieswere performed in the immediate postoperative period. IntraoperativeDoppler appearances in the group as a whole were normal; therewas a significant deterioration in Doppler appearances in thefirst 24–48 h of the postoperative period. In the absenceof rejection subsequent Doppler appearances returned to normal.An abnormal Doppler appearance immediately following transplantationshould be an expected result. If the Doppler fails to improve,or deteriorates having started to improve, rejection shouldbe strongly suspected.     

Evaluation of renal transplant dysfunction by duplex Doppler sonography: a prospective study and review of the literature

A disconcertingly wide variation exists in the literature as to the accuracy of duplex Doppler sonography in the detection of acute renal transplant rejection. Sensitivities range from 9% to 76%. In an attempt to explain the disparity of results, we undertook a double-blind prospective study of the accuracy of duplex Doppler ultrasound in the detection of acute rejection in renal transplants. We scanned 49 consecutive patients with a total of 65 biopsies; 46 biopsies in 33 consecutive patients were included in our study. In our population, the prevalence of acute rejection was 61% (28/46). Using a resistive index (RI) cutoff of greater than 0.90 based on the main renal artery flow pattern, the sensitivity of our test was 43%, with a 67% specificity. The positive predictive value was 67%. Our results are contrasted and compared with the published data from other groups in a critical survey of the literature. We conclude that duplex Doppler sonography alone is inadequate to evaluate acute rejection in renal transplants.     

Evaluation of the vertebral arteries with duplex sonography

Using duplex sonography, we have routinely evaluated the vertebral arteries as part of the carotid artery examination in 453 consecutive patients over a 6-month period. Sixty-two of these 906 vessels could not be adequately evaluated, primarily because these vessels lay too deep within the vertebral structures, resulting in a technical failure rate of 6.8%. For the remaining 844 vessels, 74.4% were considered normal by Doppler flowmeter spectral analysis. Angiographic correlation was available for 224 vessels; of 155 judged normal by duplex sonography, 144 (93%) were shown to be normal or have only mild atherosclerotic disease. Eleven vessels were considered either occluded or to have severe disease by duplex sonography, and angiography showed this to be the case in 10 (91%) vessels. Unusually strong vertebral artery flow was associated with hemodynamically significant carotid or contralateral vertebral atherosclerotic disease or subclavian steal 82% of the time. Twelve cases of subclavian steal, only one of which was symptomatic, were identified by duplex sonography; four of these were confirmed by angiography. Angiographic correlation was available for 229 vessels in which duplex evaluation showed vertebral artery flow to be moderately damped. In 11 of these (38%), angiography showed greater than 50% stenosis. Angiography judged the remaining 18 vessels in this group normal; these vessels may represent a small subgroup of patients with normal anatomy or only mild atherosclerotic disease, but with hemodynamic dysfunction that can be identified with the duplex technique.     

Intraoperative duplex sonography during renal artery reconstruction

To assess renal duplex sonography as an intraoperative study to detect technical defects during repair, 57 renal artery reconstructions in 35 patients were studied. Sixteen men and 19 women (mean age, 62 years) underwent unilateral (13 patients) or bilateral (22 patients) renal artery repair to 57 kidneys. Methods of repair included aortorenal bypass grafting in 29 cases (20 saphenous vein, 5 polytetrafluoroethylene, 4 Dacron), reimplantation in 7, transrenal thromboendarterectomy with patch angioplasty in 13, and transaortic extraction thromboendarterectomy in 8. Branch renal artery repair was required in six cases (five in vivo, one ex vivo). Fourteen patients had combined aortic replacement (11 patients: 8 abdominal aortic aneurysms, 3 aortic occlusions) or visceral artery reconstruction (three patients: three superior mesenteric artery thromboendarterectomies, one inferior mesenteric artery thromboendarterectomy). Intraoperative renal duplex sonography (mean scan time, 4.5 minutes) was complete in 56 of 57 repairs (98%), and renal duplex sonography was normal in 44 repairs (77%). Overall, B-scan defects were present in 13 repairs (23%). Six of these (11%) were defined as major B-scan defects by Doppler spectra with focal increases in peak systolic velocity greater than or equal to 2.0 meters/sec (major defect, mean renal artery peak systolic velocity, 3.1 m/sec), which prompted immediate operative revision. Seven B-scan defects were defined as minor by Doppler spectra (minor defect, mean renal artery, peak systolic velocity, 0.7 m/sec) and were not revised. Postoperative evaluation (range, 1 to 22 months; mean follow-up, 12.4 months) of 55 renal artery repairs in 34 operative survivors (surface renal duplex sonography, 33 patients; renal angiography, 9 patients) demonstrated 42/43 renal artery repairs with normal intraoperative renal duplex sonography, and 6/6 repairs with minor B-scan defects were patent and free of critical stenosis. Of the 6 renal artery revisions prompted by major B-scan defects, 4 remained patent, 1 stenosed, and 1 occluded. Our experience suggests that intraoperative renal duplex sonography during renal artery repair provides valuable anatomic and physiologic information. Renal artery repairs with normal renal duplex sonography and minor B-scan defects without Doppler spectral changes demonstrated 98% patency without critical stenosis at 12.4 months of mean follow-up. However, major B-scan defects defined by a focal increase in renal artery peak systolic velocity should be considered for immediate correction.     

Thyroid nodules: Evaluation with power Doppler and duplex Doppler ultrasound

This study purposes a new classification of thyroid nodules blood flow by power duplex Doppler ultrasound. A total of 177 nodules were studied with B-mode scanning, power Doppler, and spectral analysis. These data were compared with cytological results from ultrasound-guided fine-needle aspiration biopsy. Univariate and multivariate logistic regression analysis were performed. The power Doppler analysis of the nodules produced 5 vascular patterns: I, absence of signal blood flow; II, exclusively perinodular blood flow; III, perinodular >/= central blood flow; IV, central blood flow > perinodular blood flow; V, exclusively central blood flow. Statistical analysis revealed a significant relationship between these vascular patterns and cytological results. The spectral analysis demonstrated that the resistance index were higher in nodules with malignant versus other cytology ( P < 0.001). The results indicate that power duplex Doppler facilitates screening of thyroid nodules at high risk for malignancy with elevated sensitivity (92.3%) and specificity (88%).     

Detection of hepatic metastases using duplex/color Doppler sonography.

Current imaging modalities are unable to detect small liver metastases because of limited resolution and contrast differentiation. The association between liver metastases and altered liver blood flow has been demonstrated by dynamic scintigraphy, but the clinical feasibility of this test has been questioned. In this study a novel approach to detecting liver metastases was assessed by measurement of liver blood flow using a duplex/color Doppler System. Hepatic arterial and portal venous blood flows were measured in 16 controls, 50 patients with gastrointestinal cancer, and 6 patients with breast cancer. The ratio of hepatic arterial to total liver blood flow (Doppler perfusion index, DPI) and the ratio of hepatic arterial: portal venous blood flow (Doppler flow ratio, DFR) were calculated. The DPI and DFR values of controls and patients with overt liver metastases were clearly separated (p less than 0.0001). The results suggest that duplex/color Doppler ultrasound measurement of hepatic perfusion changes may be of value in the detection of liver metastases.     

Doppler sonography and color duplex imaging for planning a perforator flap

The most critical factor to predict viability for any muscle perforator flap is an adequate circulation. Therefore, it is advantageous during preoperative planning to have the capability to localize the requisite cutaneous perforator. Color duplex imaging fulfills this requirement and permits the identification of additional characteristics, including caliber, course, and flow velocity of essential perforators and any source vessel. Nevertheless, with the current state of technology, Doppler sonography remains a more rapid, convenient, and simpler method for perforator localization.     

Value of duplex Doppler ultrasonography in renal colic

OBJECTIVES: The aim of our study was to determine the value of duplex Doppler ultrasonography (DDU) in the patients' evolution with renal colic. The study of the resistive index (RI), difference of the RI (ARI) associated with a DDU intravesical recording (ureteral jets) were compared with renographic findings in renal colic. PATIENTS AND METHODS: Between October 1998 and January 2001 we studied 377 cases with suspected renal colic by intravenous pyelography (IVP), grey-scale ultrasonography and DDU with determination of the RI, the difference between the RI of ipsilateral and contralateral kidneys (ARI) and the amplitude (maximum length of the intravesical ureteral jet), velocity and frequency of the urine bolus. We considered normal values RI < or = 0.70 and ARI < or = 0.06. VP was used as a referee investigation and the ureteral intravesical jets were determined in standard conditions. All patients came to the hospital between 4 and 12 h after the onset of the renal colic. RESULTS: We found four series of patients: 1, acute (complete) obstructed kidney (IVP nonfunctional) and dilatation at normal grey-scale, with normal contralateral kidney (n = 153). In this series we found RI > 0.70 in 87%, RI > 0.06 in 90% and absent ureteral intravesical jet of the obstructed kidney site in 89%; 2, acute (complete) obstructed kidney (IVP nonfunctional) without abnormalities at normal grey-scale, with normal contralateral kidney (n = 57). In this series we found RI > or = 0.70 in 73.5%, deltaRI > 0.06 in 82.5% of patients, absent or asymmetric ureteral intravesical jet in 80.7% of cases; 3, incomplete obstructed kidney (IVP with various degree of ureterohydronephrosis) with normal contralateral kidney (n = 96). In this series we found RI > or = 0.70 in 58.3% and deltaRI > 0.06 in 64.5% of patients, asymmetric ureteral intravesical jets in 74% of cases; 4, normal both kidneys normal IVP) were found in 71 cases (18.8%). In this series we found RI < 0.70 in 80.2%, deltaRI < or = 0.06 in 89% of cases, normal ureteral intravesical jets in 93% of cases. The mean RI was 0.76 (0.05) in 306 obstructed kidneys, significantly higher than the mean RI of 0.62 (0.05) in 448 normal kidneys (P < 0.001). The ARI in patients with obstruction was significantly higher than in patients with normal both kidneys, at 0.08 (0.05) and -0.001 (0.03), respectively (P < 0.001). The RI was sensitive in 75.5% and specific in 92.5% and ARI was sensitive in 80.7% and specific in 95.7% (versus IVP, considered the referee value). The presence of the intravesical ureteral jets of the renal colic side, associated with the values of RI (RI < or = 0.70) and deltaRI (deltaRI < or = 0.06), was followed by spontaneous passage of the stones in 71% of cases. CONCLUSIONS: Renal DDU and consecutively, intravesical evaluation of ureteral jets could detect acute renal obstruction and, as a functional investigation, could have a predictive value regarding the ureteral stones passage. It could replace the IVP, being a sensitive and highly specific test.     

Evaluation of cortical perfusion in renal transplants: application of quantified power Doppler ultrasonography

Perfusion of renal transplants may be altered by various pathological conditions. This study assessed cortical perfusion of renal transplants during acute rejection episodes using power Doppler quantification. Forty-eight renal transplant patients with clinical indications for biopsy were included in this study. Power Doppler ultrasonography (US) of these renal transplants was performed prior to biopsy. Power Doppler image intensity in the proximal outer cortex of renal transplants was quantified by image analysis software. The results of power Doppler quantification were compared with the clinical data and histological findings. Biopsies were classified into three groups based on Banff diagnostic categories: group 1 (no acute rejection; 26 patients), group 2 (acute cell-mediated rejection alone; 12 patients), and group 3 (acute antibody-mediated rejection with/or without acute cell-mediated rejection; 10 patients). The power Doppler intensity of the outer renal cortex was 1.98 +/- 1.50 dB for group 1, 1.38 +/- 0.86 dB for group 2, and 0.81 +/- 0.66 dB for group 3. Statistically, there was a significant difference between group 1 and group 3 (1.98 vs 0.81 dB, P = .01) but not between group 1 and group 2 (1.98 vs 1.38 dB, P = .34). In conclusion, the status of cortical perfusion of renal transplants can be determined noninvasively by quantified power Doppler US. Accordingly, acute antibody-mediated rejection is associated with significantly decreased cortical perfusion, which, we propose, is due to this distinct pathological process.     

Renal duplex sonography: main renal artery versus hilar analysis

OBJECTIVE: The purpose of this study was to compare the accuracy of main renal artery Doppler scanning interrogation and hilar analysis to diagnose hemodynamically significant renal artery disease. METHODS: From January 1998 to August 1999, 41 patients had renal duplex sonography with both main renal artery interrogation and hilar analysis followed by angiography. They form the basis of this review. The sample consisted of 24 men and 17 women, with a mean age of 68.9 +/- 10.2 years, who provided 80 kidneys for comparative analysis. Significant renal artery disease revealed through angiography was defined as >/= 60% diameter-reducing stenosis or occlusion. Peak systolic velocity (PSV) (in meters per second) and the presence of poststenotic turbulence (PST) were determined from main renal artery interrogation. Acceleration time (AT) (in milliseconds) was measured by means of hilar analysis. Significant renal artery stenosis was defined by a PSV of 2.0 m/s or more and a PST or an AT more than 100 ms. Sensitivity analyses of both PSV and AT were examined, and 95% CIs were computed. Receiver operating characteristic curves were used to estimate optimal values for PSV and AT. RESULTS: Angiography revealed hemodynamically significant fibromuscular dysplasia in 5 kidneys (4 patients), atherosclerotic stenosis >/= 60% in 48 kidneys (30 patients), and renal artery occlusion in 4 kidneys (4 patients). Kidneys with significant renal artery stenosis had a higher PSV (2.54 +/- 0.11 vs 1.28 +/- 0.08, P <.001) and AT (82.43 +/- 7.2 vs 30.0 +/- 2.8, P <.001) compared with those without stenosis. Compared with angiography, a PSV of 2.0 m/s or more and PST demonstrated a sensitivity of 91%, specificity of 96%, and overall accuracy of 92% for detection of significant renal artery stenosis. Two of five studies with false-negative results reflected diseased polar vessels. By contrast, AT of more than 100 ms had a sensitivity of 32%, specificity of 100%, and overall accuracy of 54%. Receiver operating characteristic curve analysis revealed a PSV of more than 1.8 m/s and an AT of 58 ms or greater as optimal values. With an AT of 58 ms or more, the sensitivity was 58%, and specificity was 96%, with an overall accuracy of 70%. There were no apparent associations between PSV or AT and type or location of renal artery lesion, serum creatinine level, or end-diastolic ratio. CONCLUSION: Main renal artery interrogation is an accurate screening test to detect significant stenosis or occlusion of the main renal artery. Hilar analysis alone does not provide sufficient sensitivity to be used as a sole screening study. Neither method detects the presence of renovascular disease associated with polar vessels.     

Captopril renography and duplex Doppler sonography in the diagnosis of renovascular hypertension

Background. The purpose of this prospective study was to determine the clinical usefulness of captopril renal scintigraphy and duplex Doppler sonography in detecting haemodynamically significant renal artery stenosis (⩾60%) and predicting cure or improvement of hypertension following revascularisation. Methods. Twenty-eight patients with moderate or high index of clinical suspicion of renovascular hypertension underwent both captopril renal scintigraphy and duplex Doppler sonography before undergoing renal angiography. Patients with angiographically proved (⩾60%) RAS were treated by percutaneous transluminal renal angioplasty unless it was contraindicated. Results. The results of captopril renal scintigraphy and duplex Doppler sonography were compared by renal angiography of 45 renal arteries in 28 patients. Eleven renal arteries were excluded from further comparison, because no accurate Doppler signal could be obtained. The sensitivity and specificity of captopril renal scintigraphy in the identification of RAS (⩾60%) was 78% and 81% respectively. The sensitivity of duplex Doppler sonography was 83% and the specificity was 81%. Positive predictive values of both tests for blood pressure cure or improvement after PTRA were 86% for CRS and 85% for DDS. Conclusions. Captopril renal scintigraphy and duplex Doppler sonography are comparable tests for detection of patients with haemodynamically significant renal artery stenosis (⩾60%). Positive predictive values of both tests for cure or improvement of hypertension after percutaneous transluminal renal angioplasty are good and comparable.     

Assessment of obstruction in adult ureterocele by means of color Doppler duplex sonography

AIM: The purpose of this study is to present a method for identifying a ureteral obstruction in unilateral orthotopic ureterocele by means of conventional sonography and color Doppler duplex sonography. We focus on the measurement of the ureterocele dimensions, the degree of dilation it causes to the ipsilateral upper urinary tract, the registration of urine out-flow from the ureteral orifice into the bladder and its spectral analysis. MATERIAL AND METHOD: Over 2 years at our institutions, 8 adult patients (7 women, 1 man) were diagnosed as having a single system orthotopic ureterocele. Four of them presented with lumbar pain, dysuria and recurrent urinary tract infections, while the remainder were asymptomatic and diagnosed accidentally. The diagnosis was based on serial sonography of the upper and lower urinary tract confirmed by intravenous pyelography and cystoscopy. We also performed color Doppler duplex sonographic evaluation of the urine jets ejected from both ureteral orifices into the bladder. Using the flow spectral study we analyzed the waveforms and measured their duration and flow rate. The study was completed with a comparative analysis of the data obtained from both ureteral orifices. RESULTS: Cystic dilation of the lower ureteric extremity into the bladder was presented in all cases. Upper urinary tract dilation, of various grades, was present in 4 of 8 patients. Differences in urine jets between those derived from the ureterocele and those from the healthy contralateral ureteral orifice were significant in those patients with dilation of the upper urinary tract. The differences concerned mainly the frequency and symmetry of the jets as well as the pattern, duration and velocity of their waves. The 4 above-mentioned patients, with dilated upper urinary tracts and waveforms differentiated from the contralateral ones, were characterized as obstructive. On the other hand, the remaining 4 patients with subclinical ureterocele showed insignificant differences in urine jets and waveforms, and were found to be non-obstructive. CONCLUSION: Conventional sonography of the urinary tract in combination with color Doppler duplex sonography of the ureteral jets can be used in an attempt to diagnose and evaluate a unilateral orthotopic (single system) ureterocele and assess the necessity of intervention to identify the obstruction.     

双功能多普勒彩超在CVI复发病例中的诊断价值

目的对照下肢顺行静脉造影,评价双功能多普勒彩超在CVI术后复发病例的诊断价值。方法针对22例24侧下肢慢性静脉功能不全（CVI）术后复发肢体,应用双功能多普勒彩超和下肢顺行静脉造影,明确复发原因并比较两者优缺点。结果从复发原因看,95．83％（23／24）的病例存在交通静脉功能不全,70．83％（17／24）的病例存在隐静脉主干及部分属支残留,66．67％（16／24）的病例存在深静脉瓣膜功能不全。在判断静脉通畅性上,下肢静脉造影优于双功彩超,其诊断准确率达100％,无一漏诊;两者在深静脉功能判断上符合率87．5％;双功能彩超在隐静脉主干及近侧属支阳性检出率达100％,高于下肢静脉造影,后者的符合率为79．16％;双功能彩超能精确定位交通静脉,对交通静脉的漏诊率（5．11％）低于下肢顺行静脉造影（28．31％）。结论双功能彩超对CVI术后复发病例的病因及定位诊断,尤其是隐-股静脉交界处的病因分析和交通静脉精确定位,具有下肢静脉造影不可替代的优势。     

Evaluation of the effects of sildenafil citrate (Viagra) on canine renal artery,carotid and aortic blood flow with the aid of color Doppler sonography

INTRODUCTION: Erectile dysfunction is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. Oral use of sildenafil citrate has been proved to be effective in the treatment of erectile dysfunction. Although the effects of sildenafil citrate have been investigated in several studies, its effect on aortic, carotid and renal artery blood flow is unknown. The aim of this study was to investigate the early and late phase effects of sildenafil citrate on canine aortic, carotid and renal artery blood flow using color Doppler sonography (CDS). MATERIALS AND METHODS: A total of 6 healthy adult dogs was used in this study. With the aid of CDS peak systolic flow rate, end diastolic flow rate, resistivity index (RI) and pulsatility index in aortic, renal and carotid artery were determined before the administration of sildenafil citrate, 45-75 min after drug administration and after 15 days of drug administration. Data were statistically analyzed using Friedman and Wilcoxon rank tests. p < 0.05 was considered to be statistically significant. RESULTS AND CONCLUSIONS: Significant changes were determined in only 4 out of 28 parameters studied. The significantly changed parameters were as follows: a significant increase in the early and late phase of the postdrug peak of systolic aortic blood flow compared to values before drug administration, an increase in pre- and postdrug RI values of the aorta, a significant decrease in maximum velocity of the right carotid artery, and peak systolic maximum velocity of the left renal segmental artery after drug administration compared to their respective predrug basal values. The results from this study indicate that sildenafil citrate has no significant effects on aortic, renal and carotid artery blood flow rate either in the early or in the late phase. Since this study involved only 6 dogs there is a need for further clinical studies involving larger groups of subjects to conclude that this drug is safe with respect to the hemodynamic parameters evaluated in this study.