Diagnostic accuracy of colour Doppler ultrasonography, CT angiography and blood-pool-enhanced MR angiography in assessing carotid stenosis: a comparative study with DSA in 170 patients.

PURPOSE: This study was undertaken to prospectively evaluate the diagnostic performance of colour Doppler ultrasonography (CDUS), first-pass (FP) and steady-state (SS) contrast-enhanced magnetic resonance angiography (MRA) and computed tomography angiography (CTA) of the carotid arteries using digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: A total of 170 patients with previous cerebrovascular events and suspected carotid artery stenoses underwent CDUS, blood-pool MRA, CTA and DSA. Accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for CDUS, FP MRA, SS MRA and CTA. The McNemar and Wilcoxon tests and receiver operating characteristic (ROC) curve analysis were used to determine significant differences (p<0.05) between the diagnostic performances of the four modalities, and the degree of stenosis was compared using linear regression. RESULTS: A total of 336 carotid bifurcations were studied. The area under the curve (AUC) for degree of stenosis was: CDUS 0.85±0.02, FP MRA 0.982±0.005, SS MRA 0.994±0.002 and CTA 0.997±0.001. AUC analysis showed no statistically significant difference between CTA and MRA (p=0.0174) and a statistically significant difference between CDUS and the other techniques (p<0.001). Plaque morphology analysis showed no significant difference between CTA and SS MRA; a significant difference was seen between CTA and SS MRA versus FP MRA (p=0.04) and CDUS (p=0.038). Plaque ulceration analysis showed a statistically significant difference between MRA and CTA (0.04< p<0.046) versus CDUS (p=0.019). CONCLUSIONS: CTA is the most accurate technique for evaluating carotid stenoses, with a slightly better performance than MRA (97% vs. 95% for SS MRA and 92% for FP MRA) and a greater accuracy than CDUS (97% vs. 76%). Blood-pool contrast-enhanced SS sequences offer improved evaluation of degree of stenosis and plaque morphology with accuracy substantially identical to CTA.

Low-dose contrast-enhanced time-resolved MR angiography at 3T: diagnostic accuracy for treatment planning and follow-up of vascular malformations.

AIM: To assess the accuracy of low-dose contrast-enhanced time-resolved 3T magnetic resonance angiography (MRA) for the morphological and functional assessment of vascular malformations (VM), and to evaluate its diagnostic potential for the depiction of treatment-induced changes. MATERIALS AND METHODS: Twenty-five patients with known VM underwent MRA to evaluate the location and extent of lesions and their haemodynamic characteristics. Three-dimensional (3D) T1-weighted time-resolved sequences were acquired following the administration of 0.05mmol/kg of gadobenate dimeglumine. VM were classified according to their morphology and haemodynamic characteristics. All patients thereafter underwent conventional angiography to confirm the diagnosis and to treat the lesions (embolization or sclerotherapy). Follow-up MRA was performed 30 days after treatment to assess morphological and functional changes. A visual analogue scale (VAS) was used to clinically assess the severity of symptoms before and after therapy. RESULTS: Based on haemodynamic characteristics, VM were classified as predominantly arterial [4 (16%)], artero-venous [19 (76%)] or venous [2 (8%)]. Twenty-three (92%) lesions were classified as high-flow VM and two (8%) as low-flow VM. Intralesional thrombosis was present in 17 (68%) lesions before therapy and in 10 lesions (40%) after therapy. The median VAS scores were 5±1 before treatment and 4±2 after treatment. Very good correlation (Spearman's correlation coefficient: rho=0.87; p=0.000) was noted between the reduction of lesion size on follow-up MRA and pain relief as assessed by VAS. CONCLUSION: Low-dose contrast-enhanced time-resolved 3T MRA can be used to define morphological and functional aspects of VM accurately during treatment planning and follow-up, and can identify post-therapy changes that positively correlate with treatment outcome.

Preliminary experience with MRA in evaluating the degree of carotid stenosis and plaque morphology using high-resolution sequences after gadofosveset trisodium (Vasovist) administration: comparison with CTA and DSA.

PURPOSE: The authors performed a preliminary study with blood-pool contrast-enhanced magnetic resonance angiography (MRA) in evaluating the degree of carotid artery stenosis and plaque morphology, comparing the diagnostic performance of first-pass (FP) and steady-state (SS) acquisitions with 64-slice computed tomography angiography (CTA) and using digital subtraction angiography (DSA) as the reference standard. MATERIALS AND METHODS: Twenty patients with >or=50% carotid artery stenosis at Doppler sonography underwent blood-pool contrast-enhanced MRA, CTA and DSA. Two independent radiologists evaluated MRA and CTA examinations to assess the degree of stenosis and characterise plaque morphology. Accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for FP, SS and CTA. The McNemar and Wilcoxon tests were used to determine significant differences (p<0.05) between the diagnostic performance of the three modalities. RESULTS: Forty carotid bifurcations were studied. For stenosis grading, accuracy, sensitivity, specificity, PPV and NPV were 90%, 89%, 90%, 89% and 90%, respectively, at FP; 95%, 95%, 95%, 95% and 95%, respectively, at SS; and 97.5%, 95%, 100%, 100% and 95%, respectively, at CTA. SS and CTA were superior to FP for evaluating the degree of stenosis (p<0.05). For evaluating plaque morphology, accuracy, sensitivity, specificity, PPV and NPV were 87.5%, 89%, 86%, 85% and 90%, respectively, at FP; 97.5%, 100%, 95%, 95% and 100%, respectively, at SS; and 100%, 100%, 100%, 100% and 100%, respectively, at CTA. There were no significant differences between FP, SS and CTA for plaque assessment (p>0.05). CONCLUSIONS: Blood-pool contrast-enhanced MRA with SS sequences allow improved diagnostic evaluation of the degree of carotid stenosis and plaque morphology compared with FP and is substantially equal to CTA and DSA.

Diagnostic performance of 64-MDCT and 1.5-T MRI with high-resolution sequences in the T staging of gastric cancer: a comparative analysis with histopathology.

PURPOSE: This study was undertaken to compare the accuracy of magnetic resonance (MR) imaging and 64-slice multidetector computed tomography (64-MDCT) in the T staging of gastric carcinoma in comparison with histopathology. MATERIALS AND METHODS: Forty patients with an endoscopic diagnosis of gastric carcinoma underwent preoperative MR imaging and 64-MDCT, both of which were performed after i.v. injection of scopolamine and water distension of the stomach. In the MR imaging protocol, we acquired T2-weighted turbo spin-echo (TSE) sequences, true fast imaging steady-state free precession (true-FISP) and gadolinium-enhanced T1-weighted volumetric interpolated breath-hold examination (VIBE) 3D sequences. Contrastenhanced CT scans were obtained in the arterial and venous phases. Two groups of radiologists independently reviewed the MR and 64-MDCT images. The results were compared with pathology findings. RESULTS: In the evaluation of T stage, 64-MDCT had 82.5% and MR imaging had 80% sensitivity. Accuracy of MR imaging was slightly higher than that of 64-MDCT in identifying T1 lesions (50% vs 37.5%), whereas the accuracy of 64-MDCT was higher in differentiating T2 lesions (81.2% vs 68.7%). The accuracy of MR imaging and 64-MDCT did not differ significantly in the evaluation of T3-T4 lesions (p>0.05). Understaging was observed in 20% of cases with MR imaging and in 17.5% with 64-MDCT. CONCLUSIONS: MR imaging and 64-MDCT accuracy levels did not differ in advanced stages of disease, whereas MR imaging was superior in identifying early stages of gastric cancer and can be considered a valid alternative to MDCT in clinical practice.

[Mucinous gastric adenocarcinoma and duodenal somato-statinoma. Case report]. / Adenocarcinoma gastrico di tipo mucinoso associato a somatostatinoma duodenale. Case report.

The Authors present a rare association of gastric adenocarcinoma and somatostatin-producing duodenal carcinoid. The pre-operative abdominal CT scan revealed the gastric lesions and a duodenal polypoid lesion, giving an important indication to perform a subtotal gastrectomy and a duodenal resection. The definitive diagnosis was possible with histological examination.

64-MDCT imaging of the coronary arteries and systemic arterial vascular tree in a single examination: optimisation of the scan protocol and contrast-agent administration.

PURPOSE: The aim of this study was to validate a 64-row multidetector computed tomography (64-MDCT) acquisition protocol with biphasic administration of contrast medium for comprehensive assessment of the coronary and systemic arterial tree in a single examination. MATERIALS AND METHODS: The scanning protocol comprised two acquisitions: an electrocardiograph (ECG)-gated scan at the level of the heart, followed by a total-body, low-dose scan of the systemic arterial circulation. Twenty patients were evaluated using two different strategies for contrast administration. In ten patients, the delay between the two acquisitions was set at 40 s, whereas in the remaining patients, it varied between 45 s and 65 s. For both strategies, the degree of systemic arterial opacification and the attenuation gradient between arterial and venous structures were quantitatively assessed at six extracoronary locations. Two observers evaluated in consensus the presence or absence of atherosclerosis and the degree of stenosis of arterial segments. RESULTS: Three hundred coronary segments were analysed. Arterial-wall changes were depicted in 155 (51%) segments, and in 35 (23%), the degree of stenosis was > 50%. Of the 640 extracoronary arterial segments, 250 (39%) presented atherosclerotic wall alterations, in 50 (20%), the degree of stenosis was > 50% and five were affected by aneurysmal dilatation. The magnitude of arterial opacification values and attenuation gradients between arterial and venous structures were significantly higher in patients scanned with the 40-s fixed-delay strategy. CONCLUSIONS: Whole-body CT angiography with biphasic administration of contrast agent and fixed scan delay has been shown to be a feasible and reproducible technique. Comprehensive data on the global atherosclerotic burden potentially offer important therapeutic options for subclinical, high-risk segments.

Imaging the whole body atherosclerosis: high resolution magnetic resonance angiography using blood-pool agent. Initial clinical experience.

AIM: Recently whole-body 3D MR angiography (MRA) with blood-pool contrast agent has become available. The purpose of this study was to introduce and evaluate this technique to demonstrate arterial steno-occlusive involvement in systemic atherosclerosis and to compare blood-pool enhanced MRA results with those of CT angiography (CTA) as reference modality. METHODS: Twenty patients with clinically and US documented carotid occlusive disease underwent whole-body MRA on a 1.5 T scanner and CTA on a 64-MDCT unit. Ten milliliters of a blood-pool agent (MS-235 Gadofosveset Trisodium, VASOVIST, Schering, Berlin, Germany) were administered intravenously and four 3-D MRA stations were acquired successively through automatic table moving. Images were reviewed by two observers. Overall image quality of each arterial segment was assessed and rated for both MRA and CTA examinations; MRA sensitivity, MRA specificity interobserver and intermodality agreement were calculated. RESULTS: Whole-body MRA with blood-pool contrast agent was well tolerated by all patients. It yielded a detailed display of the arterial system with a short examination time. In 14 out of 20 patients there was extensive involvement of the arterial bed by steno-occlusive atherosclerotic disease; for the identification and characterization of vessel damage in the various vascular districts MRA sensitivity was 92-100%, MRA specificity was 95-100%; in 2 cases MRA underestimated the degree of peripheral vessel stenosis. Interobserver agreement calculated with K value was 0.63, intermodality agreement with CTA was 93% (P<0.01). CONCLUSION: The whole-body MRA technique is a valuable tool for comprehensive evaluation of arterial steno-occlusive involvement in systemic arterial atherosclerosis; there is a good agreement between blood-pool enhanced MRA results and CTA, used as modality of reference.