Contrast-enhanced and unenhanced diffusion-weighted imaging of the breast at 3 T.

AIM: To evaluate the effect of intravenous gadolinium contrast agent on diffusion-weighted sequences and apparent diffusion coefficient (ADC) measurements at 3 T. MATERIALS AND METHODS: Sixty-two biopsy-proven breast lesions were included in this prospective study. Magnetic resonance imaging (MRI) was performed at 3 T, using four echo-planar diffusion-weighted sequences (7,100 ms repetition time, 84 ms echo time) with b-values of 0 and 850, and 0 and 1,000 s/mm2. The first pair of DWI sequences was taken before intravenous contrast medium injection. The second pair of sequences was taken 6.5 minutes after intravenous contrast medium administration (right after the dynamic T1 sequence). A freeform region of interest (ROI) was drawn inside the lesion excluding adjacent normal tissue, necrotic, or cystic components and ADC values were calculated. The paired samples t-test was used to assess differences between ADC measurements before and after intravenous contrast medium administration. Sensitivity, specificity, positive predictive value, negative predictive value, and area under the curve were calculated for each diffusion sequence. RESULTS: Twenty-seven malignant and 35 benign lesions were analysed. Fifty-eight lesions were masses, and four lesions were non-mass-like enhancements (NMLEs). Two of the NMLEs were malignant, and two were benign lesions. The contrast-enhanced ADC measurements were lower than the unenhanced measurements on b=850 and 1,000 s/mm2 (p<0.05). The receiver operating characteristic (ROC) analysis displayed similar area under the curve values between the different diffusion sequences. CONCLUSION: The injection of intravenous contrast medium reduces ADC values; however, the effect of contrast medium is modest. Sensitivity and specificity are not significantly affected.

Varicocele embolization: Anatomical variations of the left internal spermatic vein and endovascular treatment with different types of coils.

PURPOSE: To present anatomical variations of left internal spermatic vein and a comparison between treatments with hydrogel-coated and non-coated platinum coils in patients with varicocele. MATERIALS AND METHODS: A total of 153 men (mean age, 27.5±6.7 [SD] years; range: 18-45 years) with left sided varicocele underwent coil embolization. Anatomic variants of gonadal vein were categorized into five subtypes (I-V). Additional venous collaterals were also recorded. Three types of coils were used (hydrogel coated platinum coils, fibered coils and non-coated platinum coils). Technical success, tolerance, efficacy and safety of hydrogel coated platinum coils were recorded. Comparison between different types of coils used was made. Fisher's exact test was used for statistical analysis. RESULTS: Varicoceles were classified as type I (26.1%), type II (13.7%), type III (32.1%), type IV (18.3%) and type V (9.8%). The internal spermatic vein - renal vein angle ranged from 32°-128° (mean angle, 93.5°). Technical success was achieved in 145 patients (94.8%) without complications. The mean number of coils used was 3 (range: 1-6 coils). A total of 260 hydrogel coated platinum coils in 95 patients and 135 non-coated coils in 50 patients were deployed with no complications. No differences were noted between the different types of coils used regarding embolic efficacy and safety. A 6.2% (9/145) recurrence rate and a 33.3% (14/42) fertility rate were observed. Clinical success regarding symptom relief after painful varicocele embolization was 100% (36/36) for technically successful cases. CONCLUSION: Varicocele embolization with the use of hydrogel coated or non-coated platinum coils is technically feasible and safe without complications. No superiority of one type of coil over the other was found.

Reproducibility of apparent diffusion coefficient measurements evaluated with different workstations.

AIM: To evaluate apparent diffusion coefficient (ADC) measurements of breast lesions on different computer platforms to address post-processing influences on ADC measurement reproducibility. MATERIALS AND METHODS: One hundred biopsy-proven breast lesions were included in this prospective study. MRI examination was performed at 3 T using standard sequences and an echo planar diffusion-weighted imaging sequence with b-values of 0 and 850 s/mm2. The images were reviewed by two radiologists in consensus. Regions of interest were placed manually within the lesion, following its contour. Care was taken to exclude adjacent normal tissue or necrotic tissue and cystic components within the lesion. The mean ADC value was measured for each lesion on two different platforms: On the MRI workstation that came with the scanner and on a commercially available DICOM (digital imaging and communication in medicine) viewer. Agreement between workstation measurements was evaluated using intraclass correlation coefficient and Bland-Altman plots. RESULTS: Fifty-nine malignant and 41 benign lesions were analysed. Of the benign lesions, 28 were mass lesions and 13 were non-mass-like enhancements. In addition, 46 of the malignant lesions were masses and 13 were non-mass-like enhancements. Agreement between the two workstation measurements was high (intraclass correlation coefficients=0.981). Using Bland-Altman plots, no systematic differences were identified between workstations. Limits of agreement ranged between a minimum of -0.071×10-3 mm2/s and a maximum of 0.102×10-3 mm2/s. CONCLUSION: ADC measurements are reproducible among the workstations considered in this study.

Articular cartilage status 2 years after arthroscopic ACL reconstruction in patients with or without concomitant meniscal surgery: evaluation with 3.0T MR imaging.

PURPOSE: To assess articular cartilage changes in the knee joint as detected on 3.0T MR imaging after 2-year follow-up in patients who underwent arthroscopic anterior cruciate ligament reconstruction (ACLR) with or without concomitant meniscal surgery. METHODS: A total of twenty-nine patients (mean age 30.3 ± 10 years), who underwent arthroscopic ACLR, received clinical and imaging follow-up at an average of 27.8 ± 4.8 months after surgery. Our patients were divided into two subgroups: eighteen patients with additional meniscal injuries at the time of arthroscopic ACLR who underwent meniscal surgery and eleven patients with intact menisci. The cartilage status of all knees at the time of arthroscopic ACLR was recorded. All patients underwent an MRI scan preoperatively and at follow-up with the same imaging protocol. Cartilage status of all knee compartments was evaluated at the time of follow-up by MR imaging and the ICRS classification. RESULTS: Deterioration of the cartilage status was found at all knee compartments of our study group, with respect to the number of cartilage defects. The cartilage of the lateral femoral condyle (LFC) was most severely affected, followed by patellar and medial femoral condyle (MFC) cartilage. A statistically significant relation was found between surgery of the medial meniscus and the development of new cartilage defects in LFC (p = 0.01) and MFC (p = 0.03) after adjusting for the site of meniscal surgery. The cartilage of LFC and the status of the medial meniscus were also found to be significantly related (p = 0.04). Partial meniscectomy was found to be associated with an increased incidence of new cartilage defects when compared to either meniscal repair or absence of meniscal surgery, although it was not statistically significant. CONCLUSION: Development of new cartilage lesions was evident after 2-year follow-up in patients with arthroscopic ACLR as detected by MR imaging. There was a multicompartmental pattern of cartilage involvement, and the lateral compartment was most severely affected. Partial meniscectomy at the time of arthroscopic ACLR could be suggested as an additional risk factor for the progression of chondral lesions. LEVEL OF EVIDENCE: Prospective comparative study, Level II.

Elimination of motion and pulsation artifacts using BLADE sequences in shoulder MR imaging.

OBJECTIVES: To evaluate the ability of proton-density with fat-suppression BLADE (proprietary name for periodically rotated overlapping parallel lines with enhanced reconstruction in MR systems from Siemens Healthcare, PDFS BLADE) and turbo inversion recovery magnitude-BLADE (TIRM BLADE) sequences to reduce motion and pulsation artifacts in shoulder magnetic resonance examinations. MATERIALS AND METHODS: Forty-one consecutive patients who had been routinely scanned for shoulder examination participated in the study. The following pairs of sequences with and without BLADE were compared: (a) Oblique coronal proton-density sequence with fat saturation of 25 patients and (b) oblique sagittal T2 TIRM-weighed sequence of 20 patients. Qualitative analysis was performed by two experienced radiologists. Image motion and pulsation artifacts were also evaluated. RESULTS: In oblique coronal PDFS BLADE sequences, motion artifacts have been significantly eliminated, even in five cases of non-diagnostic value with conventional imaging. Similarly, in oblique sagittal T2 TIRM BLADE sequences, image quality has been improved, even in six cases of non-diagnostic value with conventional imaging. Furthermore, flow artifacts have been improved in more than 80% of all the cases. CONCLUSIONS: The use of BLADE sequences is recommended in shoulder imaging, especially in uncooperative patients because it effectively eliminates motion and pulsation artifacts.

Celiomesenteric trunk demonstrated by multi-detector computed tomography angiography: two cases of a rare vascular variation.

We present two cases of patients with celiomesenteric trunk in whom the celiac trunk and the superior mesenteric artery arise off a common vessel from the ventral part of the aorta, which was demonstrated by multi-detector (16 slices) computed tomography angiography (MDCTA) and confirmed by digital subtraction angiography (DSA). This is a very rare congenital vascular anomaly and its imaging demonstration is of great importance in several interventional procedures. These cases demonstrate the capability of MDCTA in the evaluation of abdominal aorta and its branches and shows that this method might replace diagnostic DSA.

Spectroscopic evaluation of glioma grading at 3T: the combined role of short and long TE.

PURPOSE: To evaluate the diagnostic value of 3T (1)H-MRS in grading cerebral gliomas using short and long echo times. METHODS: 1H-MRS was performed on 71 patients with untreated cerebral gliomas. Metabolite ratios of NAA/Cr, Cho/Cr, Cho/NAA, and mI/Cr were calculated for short and long TE and compared between low and high grade gliomas. Lipids were qualitatively evaluated. ROC analysis was performed to obtain the cut-off values for the metabolic ratios presenting statistical difference between the two glioma grades. RESULTS: Intratumoral Cho/Cr at both TEs and long TE Cho/NAA were significantly different between low and high grade gliomas. Peritumoral NAA/Cr of both TEs, as well as long TE Cho/Cr and Cho/NAA ratios, significantly differentiated the two tumor grades. Diagnostic sensitivity of peritumoral short TE NAA/Cr proved to be superior over the other metabolic ratios, whereas intratumoral short TE Cho/Cr reached the highest levels of specificity and accuracy. Overall, short TE 1H-MRS reached higher total sensitivity in predicting glioma grade, over long TE. CONCLUSION: An advantage was found in using short TE over long TE 1H-MRS in the discrimination of low versus high grade gliomas. Moreover, the results suggested that the peritumoral area of gliomas may be more valuable in predicting glioma grade than using only the intratumoral area.

Magnetic resonance spectroscopy of the breast at 3T: pre- and post-contrast evaluation for breast lesion characterization.

PURPOSE: To determine whether in vivo proton magnetic resonance spectroscopy at 3T can provide accurate breast lesion characterization, and to determine the effect of gadolinium on the resonance of tCho. METHODS: Twenty-four positive-mammogram patients were examined on a 3T MR scanner. 1H-MRS was performed before and after gadolinium administration. tCho peak was qualitatively evaluated before and after contrast injection. RESULTS: Fourteen out of 27 lesions proved to be malignant after histopathological diagnosis. Using 1H-MRS, before contrast injection, 6/14 confirmed malignancies and 11/13 benign lesions were correctly classified; while, after contrast injection, 11/14 confirmed malignancies and 12/13 benign processes were correctly classified. Post gadolinium 1H-MRS proved useful in picking up tCho signal, improving the overall accuracy, sensitivity, and specificity by 35%, 83%, and 9%, respectively. CONCLUSION: 1H-MRS overall accuracy, sensitivity, and specificity in detecting breast lesion's malignancy were increased after gadolinium administration. It is prudent to perform 1H-MRS before contrast injection in large breast lesions to avoid choline underestimation. In cases of small or non-mass lesions, it is recommended to perform 1H-MRS after contrast injection for better voxel prescription to enable a reliable preoperative diagnosis.

128-detector-row computed tomography coronary angiography assessing differences in morphology and distribution of atherosclerotic plaques between patients with and without pre-test probability of significant coronary artery disease.

OBJECTIVES: To evaluate and compare morphology, distribution and orientation of atherosclerotic plaques at the coronary arteries between patients with low and intermediate pre-test probability of significant coronary artery disease (CAD) by non-invasive coronary angiography using 128-Multi Detector Computed Tomography (MDCT). MATERIALS AND METHODS: The study included 120 patients divided into two groups according to their clinical pre-test probability of having significant CAD: 38 patients (group A) with intermediate pre-test probability and 82 patients (group B) with low pre-test probability of significant CAD. Atherosclerotic plaques were characterized according to their morphology, distribution and orientation. RESULTS: A total of 482 plaques were analyzed. In group A, we found statistically significant higher percentages of RCA plaques (p=0.0005), of concentric (p<0.0001) and non-branching (p=0.013) plaques, of myocardial plaques (p=0.029), of plaques in distal RCA (p=0.0009) and distal LAD (p=0.001). In group B, we found statistically significant higher percentages of LAD plaques (p<0.0001), of eccentric (p<0.0001) and branching (p=0.013) plaques, of lateral plaques (p=0.012), of Medina 1.0.0 (p=0.0069), 0.1.0 (p=0.022) and 1.1.1 (p=0.0068) branching plaques, and of plaques in proximal LAD (p=0.02). CONCLUSION: 128-MDCT coronary angiography can provide important information on morphology and distribution of atherosclerotic plaques and may in the future play a potential role in patient management.

T2 FLAIR Increased Signal Intensity at the Posterior Limb of the Internal Capsule: Clinical Significance in ALS Patients.

Amyotrophic lateral sclerosis (ALS) is characterized by progressive upper and lower motor neuron degeneration. A hyperintense signal on T2-weighted images along the corticospinal tract has been reported in patients with confirmed ALS. However, the specificity of this finding is under consideration, since it is also identified in healthy controls. Moreover, the correlation of this finding with disease progression has not yet been established. The purpose of our study is to evaluate the frequency with which this high signal appears in the posterior limb of the internal capsule (PLIC), compare visual with quantitative measurements, and correlate these with the progression of the disease. Our prospective clinical study included 24 patients and 51 healthy volunteers. In the ALS patient group, the diagnosis was established according to the criteria of El Escorial in the revised form of Airlee House. All patients were neurologically examined and underwent diagnostic procedures to exclude other diseases resembling ALS. The initial MRI was performed six months to two years after the onset of symptomatology. All ALS patients were clinically examined regarding their symptoms from the upper and lower motor neurons. Follow-up MRIs were performed in nine out of 24 patients over a period of six months. Signal changes in the PLIC are visually evaluated on FLAIR images, and are classified as distinct, mild or no signal change. Fractional anisotropy (FA) measurements are performed by placing a region of interest (ROI) in the PLIC bilaterally. Both findings are being compared. Mild signal changes were visualized in the PLIC in ten volunteers and seven patients. Distinct T2 FLAIR signal changes were visualized in the PLIC in seven ALS patients. No distinct signal change was visualized in the controls. Moreover this increased T2 FLAIR signal change became more accentuated with disease progress. FA measurements in patients were lower than in age-matched healthy subjects, with a further decrease with disease progression. Our findings indicate that although mild hyperintensity of the PLIC is not pathognomonic for ALS, detection of a distinct PLIC hyperintensity that gradually accentuates might actually be a sign of progressive ALS. This finding is supported by the progressively decreasing FA measurements. Larger numbers of patients need to be included and re-evaluated to obtain statistically significant results.

The roots of radiology in Greece.

This article presents as reliably as possible the roots of the Radiology specialty in Greece, from the time of the discovery of X-rays by WC Roentgen. It mentions the most important dates relevant to the foundation of the specialty of Radiology in Greece.

In vivo dosimetry during DSA of the carotid and renal arteries. Deriviation of local DRLs.

The Euratom directive 97/43 recommends the use of patient dose surveys in diagnostic radiology and the establishment of diagnostic reference dose levels (DRLs). The aims of this study are to perform measurements of the entrance surface dose (ESD) during diagnostic digital subtraction angiography (DSA) of the renal and carotid arteries using thermoluminescence dosemeters (TLDs), extraction of local DRLs, and calculation of the effective dose. Dose measurement for the staff was also performed. Dose measurements were performed on 48 participating patients. The mean effective dose was calculated to be 15.9 mSv and 8.9 mSv, for the renal and carotid DSA, respectively. The effective dose of the radiologist was calculated to be 0.022 mSv and 0.023 mSv per procedure for renal and carotid DSA respectively, when wearing a protective apron and using a movable ceiling mounted shield. Radiation dose variation depends on the physical characteristics of the patient, on the procedure preferences by radiologists and on the difficulties in conducting the procedures. The lack of DRLs for the specific examinations lead the research team to choose the DRL for DSA of the renal arteries to be 169 mGy for ESD at the pelvic region and for DSA of the carotid arteries to be 313 mGy for ESD at the region of the aortic arc.

Radiation dose to patients and staff during angiography of the lower limbs. Derivation of local dose reference levels.

BACKGROUND: The Euratom directive 97/43 recommends the use of patient dose surveys in diagnostic radiology and the establishment of reference dose levels (DRLs). PURPOSE: To perform measurements of the dose delivered during diagnostic angiography of the lower limbs using thermoluminescence dosimeters (TLDs), extraction of DRLs and estimation of the effective dose and radiation risk for this particular examination. METHODS: Dose measurement was performed on 30 patients by using TLD sachets attached in 5 different positions not only on the patient, but also to the radiologist. All the appropriate factors were recorded. Measurement of the ESD was performed after each examination. RESULTS: The mean entrance skin dose (ESD) was calculated to be 70.8, 67.7, 24.3, 18.4, 9.7 mGy at the level of aorta bifurcation, pelvis, femur, knees, and at feet, respectively. The average effective dose is 9.8 mSv with the radiation risks for fatal cancer to be 5.4 x 10(-4). The effective dose of the radiologist was calculated to be 0.023 mSv per procedure. CONCLUSION: Radiation dose variation depends on the physical characteristics of the patient, on the procedure preferences by radiologists and the difficulties in conducting procedures. The main reason for the increased patient dose, compared to other studies, is the number of frames rather than the duration of fluoroscopy. For DSA of the lower limbs, the DRL was chosen to be an entrance skin dose of 96.4 mGy in the pelvic region. The dose to the radiologist is negligible.

Symptomatic partial rotator cuff tears: diagnostic performance of ultrasound and magnetic resonance imaging with surgical correlation.

BACKGROUND: The painful shoulder is a relatively common clinical entity that may be attributed to a variety of pathologies, including partial rotator cuff tears. Conservative treatment or surgical intervention may be offered, depending on the extent of the partial tear and the degree of patient discomfort. PURPOSE: To apply ultrasound (US) imaging in order to evaluate the prevalence of partial rotator cuff tears in patients with painful shoulders. MATERIAL AND METHODS: Fifty-six patients (17 men, 39 women; mean age 53.7 years) were included in the study, with symptomatic impingement syndrome of the shoulder after having failed to respond to conservative treatment. All patients underwent US and magnetic resonance imaging (MRI) scans prior to surgical intervention. RESULTS: Arthroscopy or mini-open surgery revealed 53 cases with partial tears of the rotator cuff and three with extensive tendinopathy. Both imaging modalities detected successfully 44 cases of partial tears of the supraspinatus tendon. US imaging yielded a sensitivity of 95.6%, a specificity of 70%, an accuracy of 91%, and a positive predictive accuracy of 93.6%. The corresponding values for MRI were 97.7%, 63.6%, 91%, and 91.7%, respectively. CONCLUSION: US imaging can be considered almost equally effective in detecting partial tears of the rotator cuff compared to MRI, particularly located in the area of the supraspinatus tendon. MRI may be reserved for doubtful or complex cases, in which delineation of adjacent structures is mandatory prior to surgical intervention.

The role of Doppler Perfusion Index as screening test in the characterization of focal liver lesions.

PURPOSE: Doppler Perfusion Index (DPI) has been used in the detection of overt liver metastatic disease. In the present prospective study we evaluated the use of DPI in the differential diagnosis of liver tumours. MATERIALS AND METHODS: We have included in our study 76 patients with focal hepatic lesion and 39 subjects as control group. All patients were evaluated by Color Doppler Ultrasound, and/or Spiral Computerised Tomography, Magnetic Resonance Imaging and biopsy. The radiologist performed DPI measurements was blind from the final diagnosis of the other methods. RESULTS: DPI measurements in the control group ranged from 0.07 to 0.22 (mean value 0.14), in 42 cases with benign lesions (group A) ranged from 0.05 to 0.53 (mean 0.15) and in 34 cases with malignant lesions (group B) ranged from 0.39 to 0.75 (mean 0.53). There was a statistically significant difference in DPI measurements between the control group and group B. CONCLUSIONS: Our results suggest that the DPI may differentiate malignant from benign focal hepatic lesions and therefore can be used as a screening test in the routine clinical practice.

The role of 3D-computed tomography angiography (3D-CTA) in investigation of spontaneous subarachnoid haemorrhage: comparison with digital subtraction angiography (DSA) and surgical findings.

Spontaneous subarachnoid haemorrhage is a clinical condition that may be attributed to various underlying causes, such as rupture of intracranial aneurysms and arteriovenous malformations (AVMs). Suspected cerebrovascular abnormalities can be detected either with digital subtraction angiography (DSA) or with computed tomography angiography (CTA) combined with postprocessing tools, namely multiplanar reformation, maximum intensity projection, shaded surface display, virtual endoscopy and direct volume rendering. We prospectively studied a group of 205 patients with spontaneous subarachnoid haemorrhage. One-hundred-ninety-eight patients underwent both DSA and CTA, and formed our study group. Patients with intracranial aneurysms underwent surgical or endovascualar treatment. DSA was negative for 35 patients, detected 178/179 aneurysms and 15 AVMs. CTA correctly detected 176/179 aneurysms and all 15 cases of AVMs, whereas it was negative in 35 cases. After 3D reconstruction the size, location and the relationship to the parent vessel of the aneurysms, the extent of the AVMs with the main feeding vessel(s), nidus and draining veins were reliably shown by CTA, although DSA provided more anatomic details related to the anatomy of the adjacent vessels. The accuracy, sensitivity, positive predictive accuracy and negative predictive accuracy for CTA was 98, 97.9, 100 and 94.3% and for DSA was 99, 99.3, 100 and 98%, respectively. It is suggested that CTA is a reliable alternative to DSA in detecting intracranial aneurysms. The role of CTA in demonstrating AVMs can be considered complementary to that of DSA.

Radiation dose optimisation and risk estimation to patients and staff during hysterosalpingography.

Hysterosalpingography (HSG) is an efficient radiological examination for the evaluation of the female reproductive tract. However, it involves unavoidable irradiation to the ovaries of women in childbearing age. Therefore, radiation dose optimisation is required in order to reduce the probability of the associated risks. This study attempts to: measure patient and staff doses, estimate the effective dose and radiation risk for HSG using digital fluoroscopic images. Thirty-seven patients with infertility were examined using two digital X-ray machines. Thermoluminescence dosimeters (TLD) were used to measure entrance surface dose (ESD) for patients and staff during the procedure. The mean ESD and thyroid surface dose of the patient were 3.60 and 0.17 mGy, respectively, while the mean ESD for the staff was 0.18 mGy per procedure. The patient overall risk for cancer and hereditary effects is 24 x 10(-6), while the risk for the staff is negligible. HSG with fluoroscopic technique demonstrate improved dose characteristics, compared to the conventional radiographic-based technique, reducing the surface dose by a factor of 3, without compromising the diagnostic findings.

Radiation dose measurement and risk estimation for paediatric patients undergoing micturating cystourethrography.

Micturating cystourethrography (MCU) is considered to be the gold-standard method used to detect and grade vesicoureteric reflux (VUR) and show urethral and bladder abnormalities. It accounts for 30-50% of all fluoroscopic examinations in children. Therefore, it is crucial to define and optimize the radiation dose received by a child during MCU examination, taking into account that children have a higher risk of developing radiation-induced cancer than adults. This study aims to quantify and evaluate, by means of thermoluminescence dosimetry (TLD), the radiation dose to the newborn and paediatric populations undergoing MCU using fluoroscopic imaging. Evaluation of entrance surface dose (ESD), organ and surface dose to specific radiosensitive organs was carried out. Furthermore, the surface dose to the co-patient, i.e. individuals helping in the support, care and comfort of the children during the examination, was evaluated in order to estimate the level of risk. 52 patients with mean age of 0.36 years who had undergone MCU using digital fluoroscopy were studied. ESD, surface doses to thyroid, testes/ovaries and co-patients were measured with TLDs. MCU with digital equipment and fluoroscopy-captured image technique can reduce the radiation dose by approximately 50% while still obtaining the necessary diagnostic information. Radiographic exposures were made in cases of the presence of reflux or of the difficulty in evaluating a finding. The radiation surface doses to the thyroid and testes are relatively low, whereas the radiation dose to the co-patient is negligible. The risks associated with MCU for patients and co-patients are negligible. The results of this study provide baseline data to establish reference dose levels for MCU examination in very young patients.

Imaging modalities for renal artery stenosis in suspected renovascular hypertension: prospective intraindividual comparison of color Doppler US, CT angiography, GD-enhanced MR angiography, and digital substraction angiography.

The aim of the study was to evaluate the diagnostic accuracy of Color Doppler US, CT Angiography (CTA), and GD-enhanced MR Angiography (MRA) compared with digital subtraction angiography (DSA) for the detection of renal artery stenosis in patients with clinically suspected renovascular hypertension. Fifty-eight patients with suspected renovascular hypertension were enrolled in the study. All patients underwent Color Doppler US, CTA and GD-enhanced MRA. DSA was the gold standard method for the number of renal arteries, existence and degree of stenosis, or evidence of fibromuscular dysplasia. DSA depicted 132 renal arteries, 16 stenoses, and 4 arteries with fibromuscular dysplasia. Color Doppler US failed to detect 1 main and 14 polar arteries. CTA depicted all main renal arteries and 7/16 polar arteries, but failed to detect stenosis in two accessory vessels. Likewise, MRA did not detect stenotic accessory renal arteries, depicted 9/16 polar renal arteries, but missed two main renal arteries. All methods depicted the four main renal arteries with fibromuscular dysplasia. The overall sensitivity, specificity, and positive and negative predictive accuracy were 75%, 89.6%, 60% and 94.6%, respectively, for color Doppler US; 94%, 93%, 71%, and 99%, respectively, for CTA; and 90%, 94.1%, 75%, and 98%, respectively, for GD-enhanced MRA. CTA and GD-enhanced MRA have comparable and satisfactory results with respect to the negative predictive accuracy of the suspected renal artery stenosis. The concept of an imaging algorithm including US as screening test when appropriate and CTA or MRA as the second step-procedure is suggested. Therefore, DSA may be reserved for cases with major discrepancies or therapeutic interventions.