Duplex and Doppler color echocardiography for the study of renovascular hypertension. Comparison with arteriography

Doppler US was employed to examine 46 patients with suspected renovascular hypertension (RVI) to detect stenosis/occlusion of the renal artery. In 25 cases duplex-Doppler technique was used, in 19 color-Doppler US, and 2 patients were examined with both methods. Doppler US was always performed before angiography which was considered as the reference gold standard. Using duplex-Doppler US, the diagnosis of renal artery stenosis was based on qualitative (spectral analysis of the waveform and absence of flow signal in cases of renal artery occlusion), and semiquantitative parameters (resistive index). Diagnostic accuracy of duplex US--which was compared with that of angiography--was 83%, its sensitivity was 91.6%, and specificity was 85%. With color-Doppler, two additional quantitative parameters were used (peak systolic frequency shift at the stenosis and stenosis index). In this group of patients sensitivity was 70%, specificity was 100%, and accuracy 85%. The good diagnostic yield of the method is counter-balanced by some limitations--e.g., operator dependence and long examination time (30-40 minutes, especially with duplex US). In the authors' opinion, Doppler technique can be used in the diagnosis of RVI, even though further study is necessary to exactly define diagnostic parameters, and to verify reproducibility and both inter- and intra-observer repeatibility. Technological progress may in the future reduce both difficulty and time of the examination.     

Renal arterial stenosis: prospective comparison of color Doppler US and breath-hold, three-dimensional, dynamic, gadolinium-enhanced MR angiography

PURPOSE: To compare color Doppler ultrasonography (US) with fast, breath-hold, three-dimensional, gadolinium-enhanced magnetic resonance (MR) angiography in detecting renal arterial stenosis. MATERIALS AND METHODS: Forty-five patients with clinical suspicion of renovascular disease were prospectively examined with intra- and extrarenal color Doppler US and breath-hold, gadolinium-enhanced MR angiography. Digital subtraction arteriography (DSA) was the standard of reference in all patients for the number of renal arteries and degree of stenosis. RESULTS: DSA depicted 103 arteries and 52 stenoses. Color Doppler US was nondiagnostic in two examinations. Significantly more of 13 accessory renal arteries were detected with MR angiography (n = 12) than with color Doppler US (n = 3; P <.05). For assessing all stenoses, the sensitivity and accuracy were 94% and 91%, respectively, for MR angiography and 71% and 76%, respectively, for US (P <.05). The sensitivity was higher for MR angiography (100%) than for US (79%; P <.05) in diagnosing stenoses with at least 50% narrowing. The specificity, accuracy, and negative predictive value in diagnosing stenoses of at least 50% narrowing were 93%, 95%, and 100% for MR angiography and 93%, 89%, and 90% for US. CONCLUSION: Breath-hold, gadolinium-enhanced MR angiography is superior to color Doppler US in accessory renal artery detection. Although the specificity of MR angiography is similar to that of color Doppler US, MR angiography has a better sensitivity and negative predictive value in depicting renal arterial stenoses.     

Doppler ultrasound and contrast-enhanced magnetic resonance angiography in assessing carotid artery stenosis

PURPOSE: This study prospectively compares Doppler ultrasound (Doppler US) and contrast-enhanced magnetic resonance angiography (CE-MRA) with digital subtraction angiography (DSA) and endarterectomy findings to determine the accuracy in assessing carotid artery stenosis. MATERIALS AND METHODS: Thirty-two patients underwent carotid endarterectomy, 21 studied with Doppler US, CE-MRA and DSA and 11 with Doppler US and CE-MRA. In 41 carotid arteries, the degree of stenosis was analysed with Doppler US and CE-MRA and compared with DSA by using the Spearman rank correlation coefficient. Nine out of 32 endarterectomies were done using the eversion technique, and it was possible to compare Doppler US, CE-MRA and DSA with the specimen measurement. Twenty-three out of 32 endarterectomies were done using the standard technique, and the presence of ulcers was documented. RESULTS: There was a significant Doppler US/DSA (Rs=0.86; p<0.001) and CE-MRA/DSA (Rs=0.81; p<0.001) correlation for the degree of stenosis. The diagnostic accuracy of the three methods was the same (89%). Ulcers were most frequently seen at CE-MRA, with a diagnostic accuracy of 85%. CONCLUSIONS: These data suggest that endarterectomy on the basis of Doppler US and CE-MRA can be considered appropriate. CEMRA was the best noninvasive imaging modality to detect plaque ulceration.     

Duplex sonography in the evaluation of carotid artery disease

High-resolution duplex sonography was compared with biplane magnified carotid angiography in a prospective evaluation of 161 carotid arteries in 86 patients. The duplex scanner combined real-time B-mode imaging (7.5 MHz) with simultaneous range-gated pulsed Doppler frequency analysis (3 MHz). The degree of stenosis was usually determined by the true and residual lumen of the carotid artery at the atherosclerotic plaque on the transverse image. The Doppler frequency signals were automatically converted to velocity data by a minicomputer. The accuracy of the duplex system in detecting and assessing stenoses graded in 20% increments is demonstrated according to specificity, sensitivity, and positive and negative predictive value by both cumulative and subgroup analyses. A 93.7% sensitivity was shown for minimal (0-20%) stenosis and 100% sensitivity for severe (greater than 60%) stenosis. An apparent limitation of duplex sonography is the differentiation of a high-grade stenosis from occlusion (sensitivity, 82.6%; positive predictive value, 90.4%).     

内脏动脉狭窄闭塞侧支循环的多层螺旋CT血管成像

目的:探讨腹腔动脉(CA)、肠系膜上动脉(SMA)、肠系膜下动脉(IMA)狭窄闭塞侧支循环在多层螺旋CT血管造影(MSCTA)中的表现.方法:搜集CA、SMA、IMA慢性狭窄闭塞行MSCTA检查的患者80例,采用容积再现(VR)血管添加技术(AV)对侧支血管进行选择性重建.结果:80例慢性期内脏动脉狭窄闭塞患者中SMA...     

Interobserver Variability in the Evaluation of Chronic Mesenteric Ischemia with Gadolinium-enhanced MR Angiography

RATIONALE AND OBJECTIVES: The purpose of this study was to assess interobserver variability in the interpretation of gadolinium-enhanced magnetic resonance (MR) angiograms of splanchnic vessels in patients suspected of having chronic mesenteric ischemia (CMI). MATERIALS AND METHODS: Two readers blinded to the initial interpretation retrospectively reviewed gadolinium-enhanced MR angiograms obtained for suspected CMI in 26 patients (20 women and six men; age range, 23-77 years; mean age, 61 years) who also underwent conventional angiography. Each reader graded the degree of stenosis based on the percentage diameter reduction of the celiac artery (CA), superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) by using a five-point ordinal scale: 0, no stenosis: 1, mild stenosis (<50%); 2, moderate stenosis (50%-75%); 3, severe stenosis (>75%); 4, occluded artery. Using the conventional angiogram as a reference standard, authors determined sensitivity and specificity for each observer, assigning two thresholds (grades 2 and 3) as significant stenoses. A kappa statistic (kappa) measured interobserver agreement. RESULTS: With grade 2 stenosis used as a threshold, cumulative accuracies for detecting significant stenosis were 0.95 (95% confidence interval, 0.86-0.99) for reader A and 0.97 (0.88-1.0) for reader B. Interobserver agreement for grading proximal splanchnic stenosis was 0.90 for CA, 0.92 for SMA, and 0.48 for IMA. CONCLUSION: Gadolinium-enhanced MR angiography is reproducibly accurate for detection of proximal splanchnic artery stenosis, with good to excellent interobserver agreement.     

Accuracy of ultrasound in the detection of liver fibrosis in chronic viral hepatitis

PURPOSE: To assess the accuracy of ultrasonography (US) in the identification and grading of hepatic fibrosis in patients afflicted with chronic viral liver disease, compared to histological examination as a gold standard. MATERIALS AND METHODS: We prospectively studied 105 patients (32 F, 73 M) affected by chronic viral liver disease in 36 months. Patients were studied with B-mode US and then underwent US-guided liver biopsy. All the patients were studied with conventional US with a Sequoia 512, 6.0 (Acuson, Mountain View CA, USA). We evaluated the following US parameters: liver margins, parenchymal echotexture, portal vein caliber and spleen diameter. The four B-mode US parameters were used for the US grading (from 0 to 4). Scheuer's grading (from 0 to 4) was used for the histological score. Grades 3 and 4 were considered as positive for fibrosis. Sensitivity, specificity, positive and negative predictive values and accuracy were calculated in the case of absence, positivity of one or all the US parameters. The correlation between US and histological scores was evaluated with Spearman's test. RESULTS: At histology seventy-seven patients (73%) had absent grade 0 (1 patient; 1%), low-moderate grade 1 (35 patients; 33%) or grade 2 (41 patients; 39%) liver fibrosis. Twenty-eight patients (27%) had severe grade 3 (16 patients; 15%) or grade 4 (12 patients; 11%) fibrosis. In the case of absence of US parameters sensitivity was 32%, specificity 32%, positive predictive value 15%, negative predictive value 57% and accuracy 32%. In the case of positivity of at least one of the US parameters the values were 68%, 68%, 43%, 84% and 69%. In the case of presence of all the US signs the results were 25%, 100%, 100%, 79% and 80%. None of the 77 patients with a healthy liver or with low-grade fibrosis was positive for all the US parameters. All the patients positive for all of the ultrasonographic parameters had high-grade fibrosis or cirrhosis at liver biopsy. Correlation between B-mode and histological scores was not statistically significant (Rs=0.45; p=0.0001). CONCLUSIONS: US identification of liver fibrosis in chronic liver disease is possible with 25% sensitivity, 100% specificity, 100% positive predictive value and 79% negative predictive value, with an 80% diagnostic accuracy.     

Effect of an internal carotid stenosis on orbital blood velocity.

PURPOSE: To examine how an internal carotid artery (ICA) stenosis influences the orbital blood velocity and to determine which velocity parameters are most useful. MATERIAL AND METHODS: The study group comprised 94 randomly selected patients examined with orbital US; most of the patients had a carotid artery stenosis. There were 58 men and 36 women, ranging in age from 22 to 88 years with a mean age of 63.1 years. The ICA stenosis grade was determined with carotid US. Peak systolic (Vp) and end-diastolic blood velocities, systolic acceleration, mean velocity, pulsatile index (PI) and resistance index (RI) were measured within the central retinal artery (CRA) and the ophthalmic artery (OA), and peak velocity was measured within the central retinal vein (CRV). The area under the ROC curve was used to compare the outcome of diagnostic tests. RESULTS: Only a severe (> or =80%) ICA stenosis decreased orbital blood velocity significantly, while milder stenoses did not cause significant flow decrease or side differences. According to ROC curve analysis, the threshold values giving the highest accuracy in detecting a > or =80% ICA stenosis were Vp < or =0.08 cm/s for the CRA and Vp < or =0.14 cm/s for the OA. The sensitivities for detecting a > or =80% ICA stenosis were 45% for Vp CRA and 60% for Vp OA. Systolic acceleration also decreased in severe stenoses, but RI, PI and velocity in the CRV did not correlate with ICA pathology. Reversal of OA flow was seen in 92% of ICA occlusion and in 47% of severe ICA stenosis. CONCLUSION: Orbital Doppler combined with carotid Doppler can be helpful in the diagnosis of the ocular ischaemic syndrome and in the evaluation of whether the symptoms are related to occlusion of the ophthalmic or central retinal vessels or are a consequence of carotid artery stenosis.     

Improving the Specificity of CT Angiography for the Diagnosis of Hepatic Artery Occlusion after Liver Transplantation in Suspected Patients with Doppler Ultrasound Abnormalities

ObjectiveTo investigate whether the diagnostic performance of CT angiography (CTA) could be improved by modifying the conventional criterion (anastomosis site abnormality) to diagnose hepatic artery occlusion (HAO) after liver transplantation (LT) in suspected patients with Doppler ultrasound (US) abnormalities.Materials and MethodsOne hundred thirty-four adult LT recipients (88 males and 46 females; mean age, 52.7 years) with suspected HAO on Doppler US (40 HAO and 94 non-HAO according to the reference standards) were included. We evaluated 1) abnormalities in the HA anastomosis, categorized as a cutoff, ≥ 50% stenosis at the anastomotic site, or diffuse stenosis at both graft and recipient sides around the anastomosis, and 2) abnormalities in the distal run-off, including invisibility or irregular, faint, and discontinuous enhancement. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of the conventional (considering anastomosis site abnormalities alone) and modified CTA criteria (abnormalities in both the anastomosis site and distal run-off) for the diagnosis of HAO were calculated and compared using the McNemar test.ResultsBy using the conventional criterion to diagnose HAO, the sensitivity, specificity, PPV, NPV, and accuracy were 100% (40/40), 74.5% (70/94), 62.5% (40/64), 100% (70/70), and 82.1% (110/134), respectively. The modified criterion for diagnosing HAO showed significantly increased specificity (93.6%, 88/94) and accuracy (93.3%, 125/134) compared to that with the conventional criterion (p = 0.001 and 0.002, respectively), although the sensitivity (92.5%, 37/40) decreased slightly without statistical significance (p = 0.250).ConclusionThe modified criterion considering abnormalities in both the anastomosis site and distal run-off improved the diagnostic performance of CTA for HAO in suspected patients with Doppler US abnormalities, particularly by increasing the specificity.     

Diagnostic value of MDCT angiography in assessment of coronary artery bypass graft

Purpose

To evaluate the diagnostic value of MDCT angiography in assessment of coronary bypass grafts. We studied 51 patients from April 2008 to October 2011. All patients gave written informed consent, and the study protocol was approved by the Institutional Review Board. 96 grafts including 35 left internal mammary artery (LIMA) grafts, 5 radial artery grafts, and 56 saphenous vein grafts (SVG) were assessed by 64-MDCT and the results were compared with conventional coronary angiography as reference standard.

Results

The diagnostic value of multi-detector computed tomography for graft occlusion was: 100% sensitivity, 100% specificity, 100% positive predictive value, and 100% negative predictive value. The diagnostic power of multi-detector computed tomography for stenosis of the graft anastomosis was: 100% sensitivity, 96% specificity, 87.5% positive predictive value, and 100% negative predictive value, and 96.4% accuracy.

Conclusion

Multi-detector computed tomography has become an alternative to coronary angiography to diagnose graft occlusion and stenosis after coronary artery bypass. In addition, multidetector CT has the added advantage over traditional angiographic evaluation of simultaneously allowing evaluation for alternate postoperative complications that may also manifest with chest pain and dyspnea, thereby mimicking recurrent angina.     

64-slice computed tomography coronary angiography: diagnostic accuracy in the real world

PURPOSE: This study was done to evaluate the diagnostic accuracy of 64-slice computed tomography coronary angiography (CTCA) for the detection of significant coronary artery stenosis in the real clinical world. MATERIALS AND METHOD: From the CTCA database of our institution, we enrolled 145 patients (92 men, 52 women, mean age 63.4 +/- 10.2 years) with suspected coronary artery disease. All patients presented with atypical or typical chest pain and underwent CTCA and conventional coronary angiography (CA). For the CTCA scan (Sensation 64, Siemens, Germany), we administered an IV bolus of 100 ml of iodinated contrast material (Iomeprol 400 mgI/ml, Bracco, Italy). The CTCA and CA reports used to evaluate diagnostic accuracy adopted > or =50% and > or =70%, respectively, as thresholds for significant stenosis. RESULT: Eleven patients were excluded from the analysis because of the nondiagnostic quality of CTCA. The prevalence of disease demonstrated at CA was 63% (84/134). Sensitivity, specificity and positive and negative predictive values for CTCA on a per-segment, per-vessel, and per-patient basis were 75.6%, 85.1%, 97.6%; 86.9%, 81.8%, 58.0%; 48.2%, 68.1%, 79.6%; and 95.7%, 92.3%, 93.5%, respectively. Only two out of 134 eligible patients were false negative. Heart rate did not significantly influence diagnostic accuracy, whereas the absence or minimal presence of coronary calcification improved diagnostic accuracy. The positive and negative likelihood ratios at the per-patient level were 2.32 and 0.041, respectively. CONCLUSION: CTCA in the real clinical world shows a diagnostic performance lower than reported in previous validation studies. The excellent negative predictive value and negative likelihood ratio make CTCA a noninvasive gold standard for exclusion of significant coronary artery disease.     

Economic impact of an ultrasonographic contrast agent on the diagnosis and initial management of patients with suspected renal artery stenosis.

OBJECTIVES: To determine resource use in the diagnosis and management of Canadian hypertensive patients with suspected renal artery stenosis and to estimate the impact of diagnosis with contrast-enhanced duplex Doppler ultrasonography (US) on resource use. SUBJECTS AND METHODS: Seventy-eight patients with suspected renal artery stenosis underwent usual diagnostic tests (captopril-enhanced renal scintigraphy or duplex Doppler US) and contrast-enhanced US. A management pathway ("planned") describing the medical resources required for further patient care was outlined on the basis of results from each test (separately), and a modified management pathway ("recommended"), which considered data from both diagnostic methods, was also outlined. Medical resources and productivity losses were assessed prospectively for a 3-month period after patients underwent both tests ("actual" management pathway). RESULTS: With usual diagnostic methods, 14 (18%) of the tests were inconclusive, whereas only 1 (1%) of the enhanced US examinations was inconclusive; the cost-efficacy ratio was $422 and $343 per successful diagnosis, respectively. Further management costs for patients with an inconclusive diagnosis were estimated at $6370 after the usual diagnostic tests, but only $1278 with enhanced US. Although the costs of the planned and recommended management pathways were similar ($227 and $294 per patient respectively), the proportion of patients requiring further resources was lower with enhanced US (56% v. 46%). Three-month actual management costs ranged from $121 to $1605 per patient (mean $360). Diagnostic tests and surgical procedures were the major cost drivers in all pathways, and costs were highest for patients in whom stenosis was diagnosed. CONCLUSIONS: For patients with suspected renal artery stenosis, contrast-enhanced US had a higher diagnostic success rate than usual diagnostic methods and afforded savings through lower administrative costs and lower medical resource consumption for patients whose diagnosis was unclear after usual diagnostic tests.     

Carotid artery stenosis: gray-scale and Doppler US diagnosis--Society of Radiologists in Ultrasound Consensus Conference

The Society of Radiologists in Ultrasound convened a multidisciplinary panel of experts in the field of vascular ultrasonography (US) to come to a consensus regarding Doppler US for assistance in the diagnosis of carotid artery stenosis. The panel's consensus statement is believed to represent a reasonable position on the basis of analysis of available literature and panelists' experience. Key elements of the statement include the following: (a) All internal carotid artery (ICA) examinations should be performed with gray-scale, color Doppler, and spectral Doppler US. (b) The degree of stenosis determined at gray-scale and Doppler US should be stratified into the categories of normal (no stenosis), <50% stenosis, 50%-69% stenosis, > or =70% stenosis to near occlusion, near occlusion, and total occlusion. (c) ICA peak systolic velocity (PSV) and presence of plaque on gray-scale and/or color Doppler images are primarily used in diagnosis and grading of ICA stenosis; two additional parameters, ICA-to-common carotid artery PSV ratio and ICA end-diastolic velocity may also be used when clinical or technical factors raise concern that ICA PSV may not be representative of the extent of disease. (d) ICA should be diagnosed as (i) normal when ICA PSV is less than 125 cm/sec and no plaque or intimal thickening is visible; (ii) <50% stenosis when ICA PSV is less than 125 cm/sec and plaque or intimal thickening is visible; (iii) 50%-69% stenosis when ICA PSV is 125-230 cm/sec and plaque is visible; (iv) > or =70% stenosis to near occlusion when ICA PSV is greater than 230 cm/sec and visible plaque and lumen narrowing are seen; (v) near occlusion when there is a markedly narrowed lumen at color Doppler US; and (vi) total occlusion when there is no detectable patent lumen at gray-scale US and no flow at spectral, power, and color Doppler US. (e) The final report should discuss velocity measurements and gray-scale and color Doppler findings. Study limitations should be noted when they exist. The conclusion should state an estimated degree of ICA stenosis as reflected in the above categories. The panel also considered various technical aspects of carotid US and methods for quality assessment and identified several important unanswered questions meriting future research.     

US of neurovascular occlusive disease: interpretive pearls and pitfalls.

Ultrasonography (US) of the head and neck is a convenient but operator-dependent screening tool for detection and diagnosis of neurovascular occlusive disease. In US examination of the extracranial carotid arteries, stenosis is most commonly graded according to the peak systolic Doppler velocity in the region of maximal luminal narrowing rather than according to the percentage of atheromatous plaque occupying the lumen. However, the peak systolic velocity is not always reliable in estimation of the degree of stenosis. General diagnostic pitfalls include technical difficulties with scanning, failure to review the spectral waveform patterns, the presence of additional stenotic lesions, and anatomic variants. Specific examples of pitfalls include tandem lesions, differentiation of pseudo-occlusion from true total occlusion, pseudonormalization of velocities in cases of very severe stenosis, lesions of the carotid artery origin or aortic valve, progression of subclavian steal, underestimation of severe stenosis due to heavily calcified plaque, a persistent trigeminal artery, and contralateral carotid artery stenosis. Although conventional angiography remains the standard of reference for assessment of carotid artery disease, recognition of these common sources of error in US can improve the accuracy of this noninvasive test in diagnosis of carotid artery occlusion.     

Pancreatic cancer versus chronic pancreatitis: diagnosis with CA 19-9 assessment, US, CT, and CT-guided fine-needle biopsy

The authors prospectively performed serum CA 19-9 assessment, ultrasound (US), computed tomography (CT), and CT-guided fine-needle aspiration biopsy (FNAB) of the pancreas in 81 consecutive patients with suspected chronic pancreatitis or pancreatic neoplasm. The final diagnosis was pancreatic cancer in 54 patients and chronic pancreatitis in 27 patients. CA 19-9 assessment, US, CT, and FNAB were considered nondiagnostic, respectively, in 0%, 25%, 19%, and 6% of cases. When a definite diagnosis was rendered, the positive predictive value was 90% for CA 19-9 assessment, 95% for US, 98% for CT, and 100% for FNAB; the negative predictive value was, respectively, 69%, 95%, 86%, and 100%. The accuracy of all diagnostic and nondiagnostic studies was 81% for CA 19-9 assessment, 72% for US, 77% for CT, and 94% for FNAB. It is concluded that CT-guided pancreatic FNAB is the most reliable examination for enabling differential diagnosis of pancreatic cancer and chronic pancreatitis. When the pancreas is well visualized at US, the negative predictive value for pancreatic cancer is more accurate than that of CA 19-9 assessment and CT.     

Contrast-enhanced sonography in the diagnosis of renal artery stenosis: comparison with MR-angiography

PURPOSE: To investigate the diagnostic accuracy of non-enhanced Colour-Doppler US and enhanced power-Doppler US in the diagnosis of renal artery stenosis compared with breath-hold Gd-DOTA-enhanced MR-angiography. Digital subtraction angiography (DSA) provided the gold standard. MATERIALS AND METHODS: A total of 51 patients (19 women and 32 men, age ranging from 29 to 76 years) with clinical suspicion of renovascular hypertension underwent Colour-Doppler US of the renal artery; 11 subjects (21.6%) were excluded from the study as a complete and bilateral depiction of renal artery was not obtained. The remaining 40 subjects (14 women and 26 men) were investigated with power-Doppler US with time-intensity renal enhancement curve and with MR-Angiography. All of these subjects were also studied by DSA which provided the gold standard. RESULTS: As stated, in 11 of 51 patients the diagnostic work-up was not completed because the initial US examination failed to depict the renal arteries. DSA showed renal artery stenosis in 16 of the remaining 40 patients. The sensitivity and specificity in diagnosing stenoses were 75% and 79.1% for conventional colour-Doppler US, 100% and 87.5% for enhanced power-Doppler US and 100% and 91.6% for MR-angiography. CONCLUSIONS: MR-angiography is the most reliable technique in the diagnosis of renal artery stenosis. The sensitivity and specificity of enhanced power-Doppler US are superior to those of colour-Doppler US. Although MR-Angiography enables a better evaluation of renal artery stenosis, the good diagnostic accuracy of enhanced power-Doppler US, its greater acceptance by the patients and its wider diffusion support the use of this technique in the screening of patients with clinical suspicion of renovascular hypertension.     

Gadolinium-enhanced MR angiography of visceral arteries in patients with suspected chronic mesenteric ischemia

The purpose of this study was to evaluate accuracy of dynamic gadolinium-enhanced MR angiography (MRA) of the celiac, superior, and inferior mesenteric arteries in patients with suspected mesenteric ischemia compared with catheter angiography or surgery. Sixty-five patients with suspected mesenteric ischemia underwent three-dimensional spoiled gradient-recalled acquisition in the steady state (GRASS) gadolinium-enhanced MRA. Correlative studies were performed on 14 patients, catheter angiography alone was performed on 12 patients, and surgery alone was performed on two patients. Six patients had mesenteric ischemia. In all patients, the celiac artery (CA) and superior mesenteric artery (SMA) were seen well enough to evaluate; however, the inferior mesenteric artery (IMA) could be evaluated in only 9 of the 14 patients. MRA showed severe stenosis (>75%) or occlusion of the celiac axis in seven patients, of the SMA in six patients, and of the IMA in four patients. The overall sensitivity and specificity were 100% and 95%, respectively, compared with catheter angiography and surgery. The two errors were caused by overgrading the severity of IMA disease. Three-dimensional gadolinium-enhanced MRA can accurately demonstrate the origins of the CA and SMA and is useful in evaluation of patients with suspected mesenteric ischemia.     

Quantification of internal carotid artery stenosis with duplex US: comparative analysis of different flow velocity criteria

PURPOSE: To compare 13 previously published sets of duplex ultrasonographic (US) criteria with the US criteria used at the authors' institution in terms of agreement with carotid artery angiographic results. MATERIALS AND METHODS: The authors studied 1,006 carotid arteries in 503 patients at duplex US and angiography. The degree of stenosis was determined by using duplex flow US velocities and applying 13 previously published sets of criteria and the criteria used at the authors' institution. Two independent observers evaluated the angiograms according to North American Symptomatic Carotid Endarterectomy Trial (NASCET) criteria. kappa statistics, sensitivities, specificities, positive predictive values (PPVs), negative predictive values (NPVs), and generalized linear mixed regression models were used to assess agreement between duplex US and angiographic findings. RESULTS: Stenoses of 0%-29%, 30%-49%, 50%-69%, 70%-99%, and 100% could be differentiated with 73% overall agreement between duplex US and angiographic findings according to flow velocity criteria (kappa = 0.57; 95% confidence interval [CI]: 0.54, 0.60); however, with duplex US, the angiographic degree of stenosis tended to be overestimated. In the differentiation of stenoses of less than 70%, only 45% agreement (kappa = 0.26; 95% CI: 0.23, 0.29) was observed, whereas in the differentiation of high-grade (> or =70%) stenoses, 96% agreement was observed (kappa = 0.85; 95% CI: 0.83, 0.87). The PPV and NPV for the identification of 70%-99% angiographic stenosis were 69% and 98%, respectively, with use of the most sensitive duplex US criteria. CONCLUSION: Duplex US is an excellent examination to screen for high-grade carotid artery stenosis; however, it tends to lead to an overestimation of the degree of stenosis. Exclusion of 70%-99% angiographic stenosis can be achieved with a sensitivity of up to 98%.     

Detection of renal artery stenosis: prospective comparison of captopril-enhanced Doppler sonography, captopril-enhanced scintigraphy, and MR angiography

OBJECTIVE: The objective of our study was to compare the value of captopril-enhanced Doppler sonography, captopril-enhanced renal scintigraphy, and gadolinium-enhanced MR angiography for detecting renal artery stenosis. SUBJECTS AND METHODS: Forty-one patients with suspected renovascular hypertension were prospectively examined with captopril-enhanced Doppler sonography, captopril-enhanced renal scintigraphy, gadolinium-enhanced MR angiography, and catheter angiography. The sensitivity and specificity of each technique for detecting renal artery stenosis measuring 50% or greater and 70% or greater were compared using the McNemar test. Positive and negative predictive values were estimated for populations with 5% and 30% prevalence of renal artery stenosis. Kappa values for interobserver agreement were assessed for both gadolinium-enhanced MR angiography and catheter angiography. RESULTS: For detecting renal artery stenosis measuring 50% or greater, the sensitivity of gadolinium-enhanced MR angiography (96.6%) was greater than that of captopril-enhanced Doppler sonography (69%, p = 0.005) and captopril-enhanced renal scintigraphy (41.4%, p = 0.001). No significant difference in specificity was observed among modalities. For renal artery stenosis measuring 50% or greater, positive and negative predictive values were respectively 62% and 86% for captopril-enhanced Doppler sonography, 49% and 76% for captopril-enhanced renal scintigraphy, and 53% and 98% for gadolinium-enhanced MR angiography. Interobserver agreement was high for both gadolinium-enhanced MR angiography (kappa = 0.829) and catheter angiography (kappa = 0.729). CONCLUSION: Gadolinium-enhanced MR angiography is the most accurate noninvasive modality for detecting renal artery stenosis greater than or equal to 50%. The use of captopril-enhanced Doppler sonography in combination with gadolinium-enhanced MR angiography for identifying renal artery stenosis needs to be evaluated with a cost-effectiveness analysis.     

Percutaneous Retrograde Recanalization of the Celiac Artery by Way of the Superior Mesenteric Artery for Chronic Mesenteric Ischemia

A 52-year-old man presented with recurrent postprandial abdominal pain, sitophobia, and progressive weight loss. Chronic mesenteric ischemia (CMI) due to subtotal occlusion of the superior mesenteric artery (SMA) and flush occlusion of the celiac artery (CA) was diagnosed. Retrograde recanalization of the CA by way of a collateral channel from the SMA was performed using contemporary recanalization equipment. The CA and SMA were then stented, resulting in sustained resolution of CMI-related symptoms.