[Show abstract][Hide abstract] ABSTRACT: To retrospectively assess the influence of arterial wall calcifications on the accuracy of run-off computed tomographic angiography (CTA) and to analyse whether cardiovascular risk factors are predictors of compromising calcifications.
In 200 consecutive patients who underwent run-off CTA, calcifications were assessed in pelvic, thigh and calf arteries using a four-point scale. Fifty-nine patients with digital subtraction angiography (DSA) were assessed by both techniques to estimate a threshold of compromising calcifications, defined as a decrease of sensitivity, specificity, PPV or NPV below the lower 95% confidence interval of overall results. Regression analysis was performed to investigate a potential relationship between compromising calcifications and presence of cardiovascular risk factors, advanced patient age and severe peripheral arterial disease (PAD).
The highest Ca(++)-score was chosen as the cut-off for the regression analysis, as a relevant decrease of specificity (0.91; overall: 0.95) above the knee and of sensitivity (0.66; overall: 0.83), specificity (0.65; overall: 0.93), positive predictive value (PPV) and negative predictive value (NPV) below the knee was observed. In the pelvic and thigh arteries, severe PAD (Fontaine Stage >or=III) showed the highest odds ratio for compromising calcifications (2.9), followed by diabetes mellitus (2.4), renal failure (2.1) and smoking (1.7). In the calf, renal failure (12.2) and diabetes mellitus (3.3) were the strongest predictors.
Patients with diabetes and renal failure should be considered as candidates for alternative vessel imaging in order to avoid inconclusive examination results.
No preview · Article · Sep 2009 · European Radiology
[Show abstract][Hide abstract] ABSTRACT: The objective of our study was to prospectively compare CT angiography (CTA) performed on a 16-MDCT scanner and digital subtraction angiography (DSA) in patients with peripheral arterial disease.
CTA and DSA were compared in 50 patients. CTA was independently evaluated by two blinded observers. DSA was evaluated by two additional blinded observers in consensus. Consensus DSA served as the reference standard for comparisons with CTA in terms of diagnostic quality, grading of stenoocclusive lesions, visualization of collaterals, impact on patient management, and time required for analysis.
No significant differences in diagnostic quality were observed between CTA and DSA above the ankle; both CTA observers noted significantly better visualization of pedal arteries (70 and 72 segments, respectively) than on DSA (57 segments). Of 958 stenoocclusive lesions on DSA, CTA observers 1 and 2 detected 933 and 929 lesions, respectively. Sensitivity and specificity for the detection of hemodynamically relevant (> 50%) lesions was 93.3% and 96.5% for observer 1 and 90.1% and 95.6% for observer 2. Collaterals were seen at 150 arterial levels on DSA compared with 97 and 92 levels on CTA (p < 0.05, both observers). Patient management decisions based on CTA were equivalent to those based on DSA in 49 of the 50 patients.
CTA is an effective noninvasive alternative to DSA for the evaluation of peripheral arterial disease.
No preview · Article · Oct 2007 · American Journal of Roentgenology
[Show abstract][Hide abstract] ABSTRACT: SonoVue is the first ultrasound contrast agent which allows repeated continuous examination of the liver in real time. The aim of this study was to compare low mechanical index (MI) real time contrast enhanced ultrasound of the liver, using the contrast agent SonoVue, with conventional B-mode sonography for the detection of hepatic metastases.
40 patients with known malignancy and at least one liver lesion on conventional B-mode sonography were included. Conventional B-mode sonography was performed followed by contrast enhanced ultrasound (CEUS) of the liver in the arterial (< 30 sec), portal-venous (40-120 sec) and delayed phase (> 120 sec) after injection of SonoVue. CEUS was performed using contrast specific imaging and low MI (< 0.3). Number, location and size of metastases on baseline and CEUS were compared with CT or MRI (blinded reader).
37 patients had 128 metastases on CT or MRI. Baseline US showed 74 metastases confirmed by reference examination (69%), while CEUS yielded 109 metastases (sensitivity 90%) (p < 0.001). On CEUS, 35 additional metastases not seen on baseline but confirmed by reference imaging were detected in 14 patients (36%). In 8 patients, CEUS showed 13 metastases not seen on reference imaging.
Detection of hepatic metastases is substantially improved by low MI real time contrast enhanced ultrasound with SonoVue compared to conventional B-mode sonography.
No preview · Article · Aug 2005 · Ultraschall in der Medizin