Safety of percutaneous renal cryoablation: an international multicentre experience from the EuRECA retrospective percutaneous database.

OBJECTIVE: To investigate the safety profile of percutaneous cryoablation of renal tumours < 7 cm, utilising data extracted from an international multicentre registry. MATERIALS AND METHODS: A retrospective review of all immediate and delayed complications from a multicentre database was performed and was categorised according to the Clavien-Dindo classification. Statistical analysis was performed for both overall complications (all Clavien-Dindo) and major complications (Clavien-Dindo 3 to 5). The following criteria were identified as potential predictive factors for complications: centre number, modality of image guidance, tumour size (≤ 4 cm vs. > 4 cm), number of tumours treated in the same session (1 vs. > 1) and tumour histology. RESULTS: A total of 713 renal tumours underwent ablation in 647 individual sessions. In 596 of the cases, one tumour was treated; in the remaining 51 cases, several tumours were treated per session. Mean lesion size was 2.8 cm. Fifty-four complications (Clavien-Dindo 1 to 5) occurred as a result of the 647 procedures, corresponding to an overall complication rate of 8.3%. The most frequent complication was bleeding (3.2%), with 9 cases (1.4%) requiring subsequent treatment. The rate of major complication was 3.4%. The only statistically significant prognostic factor for a major complication was a tumour size > 4 cm. CONCLUSION: Percutaneous renal cryoablation is associated with a low rate of complications. Tumours measuring more than 4 cm are associated with a higher risk of major complications. KEY POINTS: • Percutaneous kidney cryoablation has a low rate of complications. • Bleeding is the most frequent complication. • A tumour size superior to 4 cm is a predictive factor of major complication.

Evaluation of the female pelvic floor in pelvic organ prolapse using 3.0-Tesla diffusion tensor imaging and fibre tractography.

OBJECTIVES: To prospectively explore the clinical application of diffusion tensor imaging (DTI) and fibre tractography in evaluating the pelvic floor. METHODS: Ten patients with pelvic organ prolapse, ten with pelvic floor symptoms and ten asymptomatic women were included. A two-dimensional (2D) spin-echo (SE) echo-planar imaging (EPI) sequence of the pelvic floor was acquired. Offline fibre tractography and morphological analysis of pelvic magnetic resonance imaging (MRI) were performed. Inter-rater agreement for quality assessment of fibre tracking results was evaluated using weighted kappa (κ). From agreed tracking results, eigen values (λ1, λ2, λ3), mean diffusivity (MD) and fractional anisotropy (FA) were calculated. MD and FA values were compared using ANOVA. Inter-rater reliability of DTI parameters was interpreted using the intra-class correlation coefficient (ICC). RESULTS: Substantial inter-rater agreement was found (κ = 0.71 [95% CI 0.63-0.78]). Four anatomical structures were reliably identified. Substantial inter-rater agreement was found for MD and FA (ICC 0.60-0.91). No significant differences between groups were observed for anal sphincter, perineal body and puboperineal muscle. A significant difference in FA was found for internal obturator muscle between the prolapse group and the asymptomatic group (0.27 ± 0.05 vs 0.22 ± 0.03; P = 0.015). CONCLUSION: DTI with fibre tractography permits identification of part of the clinically relevant pelvic structures. Overall, no significant differences in DTI parameters were found between groups. KEY POINTS: Diffusion tensor MRI offers new insights into female pelvic floor problems. DTI allows 3D visualisation and quantification of female pelvic floor anatomy. DTI parameters from pelvic floor structures can be reliably determined. No significant differences in DTI parameters between groups with/without prolapse.

The utility of contrast enhanced MR angiography as a first stage diagnostic modality for treatment planning in lower extremity arterial occlusive disease.

INTRODUCTION: The aim of this study was to evaluate the applicability of contrast enhanced magnetic resonance angiography (ce-MRA) as a first stage imaging tool for individual treatment planning in patients with lower extremity arterial occlusive disease. PATIENTS AND METHODS: Between August, 2003 and June, 2004, in 128 consecutive patients (182 extremities) with clinical manifestations of lower limb ischemia eligible for invasive therapy, treatment was planned based on clinical assessment, ankle/brachial pressure index measurements combined with ce-MRA. Additional duplex ultrasonography (DUS) or digital subtraction angiography (DSA) was done when necessary. Ce-MRA findings were compared with findings during open surgical, endovascular or combined procedures. RESULTS: In 28 extremities (15%) ce-MRA was found inconclusive and additional imaging was performed. In the remaining patients (85% of the extremities (n = 154), treatment was initiated as planned. However, in 19 (11%) of these patients, the treatment plan was altered. In 7 of them, procedural findings did not correspond with those at the time of ce-MRA, including 6 patients (3%) with a falsely diagnosed stenosis or occlusion. In total, 62 patients received non-operative treatment (34%), 65 an endovascular procedure (36%), 49 open surgical reconstruction (27%) and 6 a combined treatment. CONCLUSIONS: We conclude that in the majority of patients treatment can be planned based on ce-MRA images, although sometimes additional DUS or DSA may be required.

Diagnostic performance of radiographers as compared to radiologists in magnetic resonance colonography.

PURPOSE: To evaluate the diagnostic performance of radiographers compared to radiologists in the detection of colorectal lesions in MR colonography. MATERIAL AND METHODS: 159 patients at increased risk of colorectal cancer were included. Four different experienced observers, one MR radiologist, one radiologist in training and two radiographers evaluated all MR colonography examinations. The protocol included T1-weighted and T2-weighted sequences in prone and supine position. Colonoscopy was used as reference standard. Mean sensitivity rates with 95% confidence intervals (CIs) were determined on a per-patient and per-polyp basis, segmented by size (>or= 6mm and >or= 10mm). Specificity was calculated on a per-patient basis. The McNemar and chi-square (chi(2)) test was used to determine significant differences. RESULTS: At colonoscopy 74 patients (47%) had normal findings; 23 patients had 40 polyps with a size > or = 6mm. In 10 patients at least 1 polyp >or= 10mm was found (20 polyps in total). Similar sensitivities for patients with lesions >or= 10mm were found for radiologists and radiographers (65% (95%CI: 44-86%) vs. 50% (95%CI: 28-72%)) (p=n.s.). For lesions >or=10mm combined per-patient specificity for radiologists and radiographers was 96% (95%CI: 94-98%) and 73% (95%CI: 68-79%) (p<0.0001). Combined per-patient sensitivity for lesions >or=6mm differed significantly between both groups of observers (57% (95%CI: 42-71%) vs. 33% (95%CI: 19-46%)) (p=0.03). CONCLUSION: Radiographers have comparable sensitivity but lower specificity relative to radiologists in the detection of colorectal lesions >or= 10mm at MR colonography. Adequate training in evaluating MR colonography is necessary, especially for readers with no prior experience with colonography.

Contrast enhanced magnetic resonance angiography versus intra-arterial digital subtraction angiography for treatment planning in patients with peripheral arterial disease: a randomised controlled diagnostic trial.

OBJECTIVES: To compare the diagnostic and therapeutic confidence, patient outcome and costs between MRA and DSA as the initial diagnostic imaging test, in patients with symptomatic arterial disease of the leg. DESIGN: Randomised controlled diagnostic trial. MATERIALS AND METHODS: Patients were randomly allocated to MRA (n=97) or DSA (n=100). Primary outcomes were: ability to make treatment plan and patients satisfaction. Secondary endpoints were: type of treatment and costs. RESULTS: A treatment plan was determined for each included patient. Additional imaging was necessary in 11% of patients in the MRA group compared to 10% in the DSA group (p=0.5). 84% of the patients who received MRA judged the diagnostic work up as comfortable compared to 57% who had DSA (p=0.013). Within 4 months of randomization 30 patients in the MRA group compared to 34 patients in de DSA group underwent operative procedures; 39 versus 36 patients respectively underwent angioplasty. The mean total in-hospital costs during the first 4 months were euro4768,- in the MRA group compared to euro4697,- in the DSA group (95% CI of difference -1331;1472). CONCLUSIONS: In patients with peripheral arterial disease of the leg an adequate treatment plan can be made with MRA. This diagnostic strategy was experienced as more comfortable and less painful compared to DSA. Total diagnostic and treatment costs of both strategies were comparable.

Cerebral ischemic disease and morphometric analyses of carotid plaques.

Atherosclerotic carotid plaque morphology and especially, intraplaque hemorrhage are assumed to be related to neurological symptoms. Most researchers have only investigated the incidence of intraplaque hemorrhage in symptomatic and asymptomatic patients. In the present study, the amount of intraplaque hemorrhage is determined in carotid endarterectomy specimens from 33 symptomatic and 14 asymptomatic patients that caused >70% luminal stenosis. The plaque components (fibrosis, lipids, intraplaque hemorrhage, calcification, and intraluminal thrombosis) were quantified as a percentage of the total plaque volume. A high incidence of intraplaque hemorrhage was found in both the symptomatic (94%, 31/33) and asymptomatic (71%, 10/14) patients. The amount of intraplaque hemorrhage was very small within the plaques of the symptomatic (0.39% +/- 0.70%) and asymptomatic (0.37% +/- 1.12%) patients. The plaques of the symptomatic patients contained more fibrosis than lipids (45.62% +/- 14.99% and 20.45% +/- 21.45%, respectively), as did the plaques of the asymptomatic patients (42. 51% +/- 15.28% and 15.46% +/- 15.22%, respectively). Finally, intraluminal thrombosis and calcification were rare. We conclude that the amount of intraplaque hemorrhage was very small and therefore question its direct role in the development of neurological symptoms. In general, the "unstable" plaque contained more fibrosis than lipids.

An in vivo evaluation of the reproducibility of intima-media thickness measurements of the carotid artery segments using B-mode ultrasound.

B-mode ultrasound may be used to measure the intima-media thickness (IMT) in subjects with a history of atherosclerosis. The variability between measurements depends on the subjective interpretation of ultrasonographers and readers. The two carotid arteries, subdivided in common (CCA), bulbus (BUL) and internal (ICA) of 10 men with proven coronary disease, were scanned twice by two ultrasonographers with a 1-week interval. The IMTs were measured off-line by two readers. The number of IMT measurements was 75 (94%) of 80 in the CCA, 61 (76%) of 80 in the BUL and 43 (54%) of 80 in the ICA segment. In the CCA segment, the agreement between readers (mean = 0.02 mm; limits: -0.26 to +0.3 mm) and between visits for each reader separately (reader 1: mean = 0.01 mm; limits: -0.33 to +0.35 mm and, reader 2: mean = 0.04 mm; limits: -0.36 to +0.44 mm) was better than in the more distal segments. Therefore, it is concluded that IMT measurements are best performed in the CCA segment.

Variance components analysis of carotid and femoral intima-media thickness measurements. REGRESS Study Group, Interuniversity Cardiology Institute of The Netherlands, Utrecht, The Netherlands. Regression Growth Evaluation Statin Study.

B-mode ultrasound intima-media thickness (IMT) measurements of carotid and femoral arterial walls are used in atherosclerosis studies. In this study, the components contributing to IMT measurement variability in males with coronary artery disease were investigated by means of repeated B-mode ultrasound scans and repeated off-line video image analyses. For statistical analysis, a mixed-model analysis of variance was used. From sonographer data, it was shown that human subjects and their arterial wall segments contributed 75% of the total IMT measurement variability in this population. Inter-sonographer variance contributed 25%. The intra-sonographer variance was negligible (<1%). In off-line image analysis, variance components due to subjects and segments, inter-analyst variance, and residual fluctuation were 88%, < 1% and 11%, respectively. Intra-analyst variance was negligible (<1%). The major source of B-mode ultrasound IMT measurement variability finds its origin in subjects and their arterial walls. Although sonographers proved a lesser source of variability, in comparative studies they should enter a study well trained and should be randomly assigned to subjects. Follow-up examinations should preferably be done by the same sonographer. Off-line image analysis contributed little to IMT measurement variability.

Ultrasonographic characterization of carotid plaques.

The composition of atherosclerotic plaques in the carotid artery is assumed to be related to the development of neurological symptoms. The echo patterns produced by B-mode ultrasound may be of use in the assessment of the plaques' composition. It is suggested that fibrotic and "stable" plaques are more echogenic than lipid/hemorrhagic and echolucent or "unstable" plaques. B-mode ultrasound procedures were performed 1 day prior to surgery on 46 consecutive endarterectomies. Two observers assessed the plaques according to their echo pattern and echogenicity and sorted them into three categories: 1) predominantly echolucent, 2) heterogeneous, and 3) predominantly echogenic. The intraobserver agreement was moderate (kappa = 0.44) and the interobserver agreement low (kappa = 0.38). Furthermore, subjective categorization of plaque types resulted in type 1 plaques being as fibrotic as type 2 or 3 plaques. We conclude that B-mode ultrasound and subsequent subjective categorization of atherosclerotic plaques cannot adequately determine the volume of fibrosis or lipids within the plaque.

B-mode ultrasound assessment of pravastatin treatment effect on carotid and femoral artery walls and its correlations with coronary arteriographic findings: a report of the Regression Growth Evaluation Statin Study (REGRESS).

OBJECTIVES: In this B-mode ultrasound study we assessed pravastatin treatment effects on carotid and femoral artery walls and investigated the correlations between the state and evolution of peripheral and coronary atherosclerosis. BACKGROUND: The Regression Growth Evaluation Statin Study (REGRESS) was an 11-center, 2-year, double-blind, placebo-controlled, prospective study of 885 men with coronary artery disease (CAD) (total cholesterol 4 to 8 mmol/liter). The study primarily investigated pravastatin treatment effects on the coronary lumen. This report focuses on the 255 patients who participated in the REGRESS ultrasound study. METHODS: Carotid and femoral artery walls were imaged at baseline and at 6, 12, 18 and 24 months. Pravastatin treatment effect was defined as the difference in progression of the combined intima-media thicknesses (IMT) between treatment groups. RESULTS: Pravastatin treatment effects were highly significant (combined IMT: p = 0.0085; combined far wall IMT: p < 0.0001; common femoral artery far wall IMT: p = 0.004). Correlations between the IMTs of the arterial wall segments ranged from -0.17 to 0.81. Baseline correlations between IMT and percent coronary lumen stenoses ranged from 0.23 to 0.36. Baseline IMT correlated with the mean coronary segment diameter (r = -0.32, p = 0.001) and minimal coronary obstruction diameter (r = -0.27, p = 0.005). There were no individual correlations between IMT and coronary lumen variables (p > 0.30). CONCLUSIONS: Pravastatin treatment effects on carotid and femoral artery walls were observed. B-mode ultrasound imaging studies of peripheral arterial walls could not describe the state and evolution of the coronary lumen in the individual patient, but proved to be a highly suitable tool for the assessment of antiatherosclerotic properties of agents.

An in vitro evaluation of the line pattern of the near and far walls of carotid arteries using B-mode ultrasound.

This in vitro study was executed to evaluate the double line pattern generated at both near and far walls of human carotid arteries using B-mode ultrasound. Therefore, extravascular (7.5 MHz) and intravascular (30 MHz) ultrasound imaging were performed at the same locations of the carotid artery. The thickness of the double line pattern of the extravascular image (7.5 MHz) was compared to the thickness of the intima-media complex seen on the corresponding intravascular image (30 MHz) and on the histologic section. At the far wall of the extravascular image, the measurements were executed at the leading edge of the echo. The data showed high correlation and agreement with the intravascular (r = 0.91, p < 0.001; mean(diff) = -0.01 and SDdiff = 0.12) and the histologic measurements (r = 0.87, p < 0.001; mean(diff) = -0.12 and SDdiff = 0.13). In addition, the results of the measurements of the intravascular image showed high correlations and agreement with the histologic data (r(near) = 0.86, p < 0.001; mean(diff) = -0.08 and SDdiff = 0.15, respectively, r(far) = 0.92, p < 0.001; mean(diff) = -0.12 and SDdiff = 0.12). For comparison with other studies, near wall measurements were also included. These had to be performed at the trailing edge of the echoes to be compatible with these studies. The results of the measurements of the extravascular image showed poor correlations and lack of agreement with those of the intravascular (r = 0.49, p = 0.03; mean(diff) = 0.09 and SDdiff = 0.25) and of the histologic (r = 0.37, p = 0.03; mean(diff) = 0.04 and SDdiff = 0.23) measurements. These results can easily be explained from the physical limitations of measuring at the trailing edges. We conclude that the double line pattern seen at the far wall of the extravascular image is representative of the intima-media complex.

Influence of biological factors on changes in mean cerebral blood flow velocity in normal ageing: a transcranial Doppler study.

Analysis of the blood flow velocities in the middle cerebral artery by transcranial Doppler ultrasonography was performed in 158 healthy volunteers (aged 14-70 years; 82 men and 76 women). In a subgroup of 38 men and 21 women the end-tidal [CO2] was also measured. The influence of biological factors such as age, sex, end-tidal [CO2], and pulsatility and resistance indices on the mean blood flow velocity in normal ageing was investigated by multiple regression analysis. In both sex groups the measured mean blood flow velocity decreased significantly with age (P values less than 0.0003 for women and less than 0.0001 for men). Women had significantly higher blood flow velocities than men (P = 0.008) and the age-corrected sex difference of 5.2 cm s-1 did not significantly depend on age (P = 0.93). The age-related linear decline of the mean blood flow velocity could not be explained by a concomitant decrease of the end-tidal [CO2]. In a group of subjects older than 50 years, the decrease of the mean blood flow velocity was significantly related to the increase of the pulsatility or resistance index.

Assessment of peripheral vascular obliterative disease by transcutaneous oxygen tension tests.

By repeated measurements in each of ten normal subjects and ten patients with mild intermittent claudication, the performance of three transcutaneous oxygen tension (PtcO2) test in the diagnosis of obliterative peripheral arterial disease was studied. PtcO2 resting value, PtcO2 response to oxygen breathing and PtcO2 reperfusion response after tourniquet obstruction were all measured on the dorsum of the foot. We found that PtcO2 resting values were not different between patients and controls, while responses to 100% oxygen breathing and reperfusion responses differed significantly between the two groups. The most prominent difference between the two groups was observed in the latency of PtcO2 rise after reperfusion. Therefore the reperfusion response test may have a place in the assessment of claudication by PtcO2 measurement.