Roberto Montisci

CT and Ultrasound in the Study of Ulcerated Carotid Plaque Compared with Surgical Results: Potentialities and Advantages of Multidetector Row CT Angiography

BACKGROUND AND PURPOSE: Ulceration is a severe complication of carotid plaque. The purpose of this study was to evaluate the role and the diagnostic efficacy of multidetector row CT angiography (MDCTA) and ultrasound (US) echo color Doppler (US-ECD) in the study of patients with carotid plaque complicated by ulceration through the comparison with the surgical observation. MATERIALS AND METHODS: From January 2004 to October 2005, 237 patients, for a total of 474 carotid arteries, studied at first with color Doppler US, were analyzed using CT angiography. A total of 103 patients underwent a carotid endarterectomy. We analyzed stenosis degree, plaque composition, and presence of ulcerations. In a second phase, the data were compared with the surgical results when the MDCTA indicated surgical intervention. RESULTS: MDCTA found 31 ulcerations; the surgical confirmation underlined a 93.75% sensitivity and a 98.59% specificity. US-ECD performances were 37.5% and 91.5% for sensitivity and specificity, respectively. The number of patients who showed plaque ulcerations increased with the severity of stenosis. Furthermore, ulcerations of the carotid plaque occurred more often proximal than distal to the point of maximum stenosis, and this trend increased with the severity of the stenosis. We also determined that fatty plaques were more likely to be affected by ulcerations. CONCLUSIONS: The results of our study suggest that MDCTA detects with higher sensitivity and specificity the presence of ulcerated plaque compared with US-ECD, which has been demonstrated to be less effective in this evaluation. Considering the high MDCTA sensitivity and specificity for detection of plaque ulceration, we therefore recommend MDCTA as a useful step for correct presurgical planning.

Carotid Artery Abnormalities and Leukoaraiosis in Elderly Patients: Evaluation with MDCT

OBJECTIVE Several studies have shown that leukoaraiosis is a clinically relevant condition. Patients with leukoaraiosis have a negative prognosis in terms of death, stroke, and myocardial infarction. The aim of this study was to evaluate whether the presence and severity of leukoaraiosis correlate with degree of carotid stenosis and the presence of specific types of plaque (fatty, mixed, calcified) in a group of elderly patients with clinical indications for MDCT. MATERIALS AND METHODS From January 2004 to March 2007, 147 consecutively registered patients 65 years and older underwent MDCT. All patients enrolled in the study cohort were assessed for the presence and severity of leukoaraiosis. Degree of carotid artery stenosis according to the North American Symptomatic Carotid Endarterectomy Trial criteria and type of plaque were evaluated. Statistical analysis was performed to determine whether an independent interaction existed among the presence of leukoaraiosis, severity of leukoaraiosis, and degree of carotid artery stenosis associated with plaque type. RESULTS A correlation was observed between the presence of leukoaraiosis and degree of carotid stenosis (Pearson correlation, 0.23; p < 0.001). A statistically significant correlation between advanced patient age and presence of leukoaraiosis (Pearson correlation, 0.32; p < 0.0001) and severity of leukoaraiosis (Pearson correlation, 0.55; p < 0.0001) was recorded. The data obtained showed a trend toward increased risk of development of leukoaraiosis (p = 0.08) in carotid arteries with fatty plaques. CONCLUSION The results of this study showed a statistically significant correlation between the presence and severity of leukoaraiosis and degree of carotid stenosis. A trend toward increased risk of development of leukoaraiosis in carotids with fatty plaques also was observed. The data confirmed that the development of leukoaraiosis is strongly correlated with age.

Imaging of the carotid artery

In the study of carotid arteries, modern techniques of imaging allow to analyze various alterations beyond simple luminal narrowing, including the morphology of atherosclerotic plaques, the arterial wall and the surrounding structures. By using CTA and MRI it is possible to obtain three-dimensional rendering of anatomic structures with excellent detail for treatment planning. This paper will detail the role of various imaging methods for the assessment of carotid artery pathology with emphasis on the detection, analysis and characterization of carotid atherosclerosis.

Multidetector-row CT angiography in the study of atherosclerotic carotid arteries.

Pathologies of the carotid arteries, and in particular atherosclerosis, are now an important medical problem. Stroke is the third leading cause of severe disability in the Western World leading to millions of deaths every year. Extracranial carotid atherosclerotic disease is the major risk factor for stroke. In years, with the advent of multidetector-row CT (MDCT) scanners and the use of specific angiographic protocols (MDCTA), CT imaging of the carotid arteries has become increasingly effective. In addition, the volume data obtained can be further rendered to generate high-quality two-dimensional and three-dimensional images. The purpose of this study was to review the atherosclerotic carotid arteries, their complications and how MDCTA depicts them, underlining the benefits and pitfalls of this diagnostic technique.

Association between carotid plaque enhancement shown by multidetector CT angiography and histologically validated microvessel density

PurposeCarotid plaques analysed by MDCTA can show contrast enhancement. The purpose of this study was to explore the association between carotid plaque enhancement (CPE) and microvessel density.Materials and methodsWe obtained IRB approval. Twenty-nine consecutive (male, 20; median age, 63) symptomatic patients studied with 16-detector CT were prospectively analysed. Examinations were performed before and after intravenous contrast medium administration, and analysis of plaque enhancement was performed. Patients underwent “en bloc” carotid endarterectomy; histological sections were prepared and the presence of microvessels quantified. Logistic regression analysis as well as ROC curve and area under the curve was calculated.ResultsA statistically significant association between the degree of CPE and microvessel density (P = 0.009; rho = 0.553) was observed. The ROC curve analysis confirmed this association with an area under the curve of 0.906, 0.735, 0.644 and 0.546 for CPE of 10 HU, 15 HU, 20 HU and 25 HU respectively. There was a statistically significant difference between the CPE and the degree of neovascularisation (P = 0.0003).ConclusionResults of this preliminary study suggest that CPE might be associated with the microvessel density. Histological analysis seems to demonstrate that the degree of intra-plaque neo-vascularisation is statistically associated with CPE.Key PointsCarotid artery plaque enhancement at CT is associated with microvessel density.The degree of intra-plaque neo-vascularisation is statistically associated with carotid plaque enhancement.Plaque enhancement at CT should be considered when assessing vulnerable plaques.

Association Between Carotid Artery Plaque Volume, Composition, and Ulceration: A Retrospective Assessment With MDCT

OBJECTIVE The purpose of this study was to evaluate the relationship between MDCT angiography-assessed carotid artery plaque volume and composition and the presence of ulceration. MATERIALS AND METHODS Seventy consecutive patients (46 men and 24 women; mean age, 63 years; age range, 42-81 years) were studied using MDCT and were retrospectively analyzed. Component types of the carotid plaque were defined according to attenuation value ranges (lipid, < 60 HU; fibrous tissue, 60-130 HU; and calcification, > 130 HU). The plaque volumes of each component were calculated. Statistical analysis was performed using the receiver operating characteristic (ROC) statistic and Wilcoxon signed rank test to evaluate the association between the presence of ulceration and specific plaque components and their volume. RESULTS Eighteen carotid arteries were excluded, and 16 ulcerated plaques were detected in the remaining 122 carotid arteries. Wilcoxon and ROC curve analysis showed a statistically significant association between increased relative lipid volume and ulceration (p = 0.0001; area under the ROC curve, 0.916). The total volume of the plaque did not show an association with the presence of ulceration (p = 0.0526). CONCLUSION The results of our retrospective study suggest that there is no correlation between total carotid atherosclerotic plaque volume and ulcerations, whereas plaque relative lipid volume (using attenuation of < 60 HU) is associated with the presence of ulceration. This finding could indicate vulnerable plaques and increased risk for cerebrovascular events.

Comparison between manual and automated analysis for the quantification of carotid wall by using sonography. A validation study with CT

PURPOSE The purpose of this paper was to compare manual and automated analysis for the quantification of carotid wall obtained with sonography by using the computed tomography as validation technique. MATERIAL AND METHODS 21 consecutive patients underwent MDCTA and ultrasound analysis of carotid arteries (mean age 68 years; age range 59-81 years). The intima-media-thickness (IMT) of the 42 carotids was measured with novel and dedicated automated software analysis (called AtheroEdge™, Biomedical Technologies, Denver, CO, USA) and by four observers that manually calculated the IMT. The carotid artery wall thickness (CAWT) was also quantified in the CT datasets. Bland-Altman statistics was employed to measure the agreement between methods. A Students t-test was used to test the differences between the IMT values of AtheroEdge™. The study obtained the IRB approval. RESULTS The correlation between automated AtheroEdge™ measurements and those of the human experts were equal to 95.5%, 73.5%, 88.9%, and 81.7%. The IMT coefficient of variation of the human experts was equal to 11.9%. By using a Students t-test, the differences between the IMT values of AtheroEdge™ and those of the human experts were not found statistically significant (p value=0.02). On comparing AtheroEdge™ (using Ultrasound) with CAWT (using CT), the results suggested a very good concordance of 84.96%. CONCLUSIONS Data of this preliminary study indicate that automated software AtheroEdge™ can analyze with precision the IMT of carotid arteries and that the concordance with CT is optimal.

Associations between Carotid Artery Wall Thickness and Cardiovascular Risk Factors Using Multidetector CT

BACKGROUND AND PURPOSE: It has been demonstrated that the increase in CAWT is associated with an increased risk of stroke and its severity. The aim of this study was to determine whether CAWT evaluated by MDCTA is associated with the following cardiovascular risk factors: hypertension, diabetes mellitus, dyslipidemia, and smoking. MATERIALS AND METHODS: This was a retrospective study. One hundred sixty-eight patients (120 men; mean age, 68.96 years ± 11.2 years SD) were analyzed by using a multidetector row CT scanner. In each patient, CAWT was measured by using an internal digital caliper. Continuous data were described as the mean value ± SD and were compared by using the Student t test. We performed simple logistic regressions to evaluate the association between CAWT and the following: hypertension, diabetes mellitus, dyslipidemia, and smoking. A P value < .05 indicated statistical significance. RESULTS: The distal common CAWT varied from 0.5 to 1.5 mm. We observed that hypertension and diabetes mellitus were associated with increased (>1 mm) CAWT (P = .0041 and P = .0172, respectively). There was no significant association between increased CAWT and dyslipidemia or smoking. CONCLUSIONS: In our selected group, the results of this work show that an increased CAWT is associated with the cardiovascular risk determinants hypertension and diabetes. Further studies are necessary to evaluate whether it is possible to apply our observations to the general population.

Multidetector-row CT angiography diagnostic sensitivity in evaluation of renal artery stenosis: comparison between multiple reconstruction techniques.

Purpose: The aim of this study was to assess the image quality and interobserver agreement of various multidetector-row computed tomographic angiography postprocessing techniques in the diagnosis of renal artery stenosis (RAS). Materials and Methods: We studied 36 patients (21 men and 15 women; mean age, 49 years) who underwent computed tomography angiography to assess renal arteries for suspected RAS. Patients were analyzed by using a multidetector-row computed tomography. Computer tomographic scans were obtained after intravenous bolus administration of 110 to 140 mL of nonionic contrast material using a 4- to 6-mL/s flow rate. We assessed every patient by using axial scans, multiplanar reconstruction (MPR), maximum intensity projection (MIP), and volume rendering (VR) techniques. For each patient and for each reconstruction method, the image quality of the main renal artery was scored as 0 for bad-quality, 1 for poor-quality, 2 for good-quality, and 3 for excellent-quality images. Two radiologists reviewed computed tomographic images independently. We calculated interobserver agreement and &kgr; value. We correlated the stenosis degree observed by the 2 readers with the type of reconstruction used. Results: Overall number of renal arteries studied was 72, and we detected 24 RAS. Quality images obtained an overall (averaged between the 2 observers) value of 133 of 216, 163 of 216, and 145 of 216 for MPR, MIP, and VR, respectively. Our data underlined a statistical difference between MPR images and VR images (P < 0.001). Moreover, we noticed that the images classified as excellent were obtained from a vessel with 350 Hounsfield units or higher. Kappa value was good in MIP and VR methods evaluation but poor with the use of MPR. Conclusions: Reformatting techniques usually provided a high visual impact, and in our study, MIP and VR showed the best diagnostic interobserver agreement in quality and reproducibility of stenosis degree.

Assessment of Intracranial Arterial Stenosis with Multidetector Row CT Angiography: A Postprocessing Techniques Comparison

BACKGROUND AND PURPOSE: It was demonstrated the some patients with stroke have intracranial stenosis of 50% or greater and the identification of intracranial arterial stenosis is extremely important in order to plan a correct therapeutical approach. The aim of this study was to assess the image quality and intertechnique agreement of various postprocessing methods in the detection of intracranial arterial stenosis. MATERIAL AND METHODS: Eighty-five patients who were studied by using a multidetector row CT scanner were retrospectively analyzed. A total of 2040 segments were examined in the 85 subjects. Intracranial vasculature was assessed by using MPR, CPR, MIP, and VR techniques. Two radiologists reviewed the CT images independently. Cohen weighted κ statistic was applied to calculate interobserver agreement and for image accuracy for each reconstruction method. Sensitivity, specificity, PPV, and NPV were also calculated by using the consensus read as the reference. RESULTS: Two hundred fifteen (10.5%) stenosed artery segments were identified by the observers in consensus. The best intermethod κ values between observers 1 and 2 were obtained by VR and MIP (κ values of 0.878 and 0.861, respectively), whereas MPR provided the lowest value (κ value of 0.282). VR showed a sensitivity for detecting stenosed segments of 88.8% and 91.6% for observers 1 and 2, respectively. The highest positive predictive value was also obtained by VR at 95% and 99% for observers 1 and 2, respectively. Image accuracy obtained by using VR was the highest among all reconstruction methods in both observers (185/255 and 177/255 for observers 1 and 2, respectively). CONCLUSIONS: The results of our study suggest that VR and MIP techniques provide the best interobserver and intertechnique concordance in the analysis of intravascular cranial stenosis.