CT Attenuation Analysis of Carotid Intraplaque Hemorrhage.

BACKGROUND AND PURPOSE: Intraplaque hemorrhage is considered a leading parameter of carotid plaque vulnerability. Our purpose was to assess the CT characteristics of intraplaque hemorrhage with histopathologic correlation to identify features that allow for confirming or ruling out the intraplaque hemorrhage. MATERIALS AND METHODS: This retrospective study included 91 patients (67 men; median age, 65 ± 7 years; age range, 41-83 years) who underwent CT angiography and carotid endarterectomy from March 2010 to May 2013. Histopathologic analysis was performed for the tissue characterization and identification of intraplaque hemorrhage. Two observers assessed the plaque's attenuation values by using an ROI (≥ 1 and ≤2 mm2). Receiver operating characteristic curve, Mann-Whitney, and Wilcoxon analyses were performed. RESULTS: A total of 169 slices were assessed (59 intraplaque hemorrhage, 63 lipid-rich necrotic core, and 47 fibrous); the average values of the intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue were 17.475 Hounsfield units (HU) and 18.407 HU, 39.476 HU and 48.048 HU, and 91.66 HU and 93.128 HU, respectively, before and after the administration of contrast medium. The Mann-Whitney test showed a statistically significant difference of HU values both in basal and after the administration of contrast material phase. Receiver operating characteristic analysis showed a statistical association between intraplaque hemorrhage and low HU values, and a threshold of 25 HU demonstrated the presence of intraplaque hemorrhage with a sensitivity and specificity of 93.22% and 92.73%, respectively. The Wilcoxon test showed that the attenuation of the plaque before and after administration of contrast material is different (intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue had P values of .006, .0001, and .018, respectively). CONCLUSIONS: The results of this preliminary study suggest that CT can be used to identify the presence of intraplaque hemorrhage according to the attenuation. A threshold of 25 HU in the volume acquired after the administration of contrast medium is associated with an optimal sensitivity and specificity. Special care should be given to the correct identification of the ROI.

Aortic valve stenosis: non-invasive preoperative evaluation using 64-slice CT angiography.

AIM: In patients affected by aortic valve stenosis (AS) it is mandatory to rule out coronary artery disease (CAD). The role of retrospectively ECG-gated 64-slice CT angiography (64-SCTA) was assessed in patients with AS referred for surgical valve replacement. METHODS: Forty-two patients with AS underwent ECG-gated 64-SCTA of thoracic aorta, including the heart and coronary arteries, before surgical valve replacement. Images were evaluated by two independent readers and compared with surgical findings in terms of aortic valve calcification grading, valvular morphology, aortic valve annulus and sino-tubular junction diameters, and valvular area planimetry. Quantitative evaluation of cusps opening was also performed. Finally, the presence of CAD, thoracic aortic aneurysm and left ventricle hypertrophy were assessed. RESULTS: Visualization of the aortic valve without motion artefacts was possible in 38 patients (90.5%). Valvular morphology was correctly assessed in all cases (100%). 64-SCTA correctly determined aortic valve calcification grading and the aortic valve annulus and sinotubular junction diameters in 100% of cases. The aortic valve planimetric area was assessed in 38 cases (90.5%). Ascending aortic aneurysms requiring surgical replacement were detected in 12 patients (28.6%). Significant left ventricle hypertrophy was found in 30 patients (71%). CONCLUSION: Preoperative evaluation of patients undergoing surgical replacement for AS with 64-SCTA is feasible. 64-SCTA can rule out CAD and evaluate the status of the aortic valve and thoracic aorta in the same examination, obtaining relevant information for surgical planning.

Rationale, design and methods of CTCA-PRORECAD (Computed Tomography Coronary Angiography Prognostic Registry for Coronary Artery Disease): a multicentre and multivendor registry.

PURPOSE: This study was done to assess the prognostic value of computed tomography coronary angiography (CTCA) in a large multicentre population of patients with suspected coronary artery disease (CAD) and, in particular, its incremental value compared with traditional methods for risk stratification. MATERIALS AND METHODS: This is a retrospective observational study that began in January 2003 conducted on patients with suspected CAD assessed with CTCA on the basis of symptoms (chest pain, dyspnoea) and/or abnormal or equivocal stress test and/or a high cardiovascular risk profile. The participating centres will provide data obtained with CTCA performed with 16-slice or higher equipment. Exclusion criteria are renal insufficiency, allergy to iodinated contrast material, pregnancy and previous myocardial infarction or revascularisation (percutaneous coronary intervention and/or coronary artery bypass graft). All patients are stratified by means of clinical assessment and/or data retrieved from a clinical database. Risk factors considered are hypertension, dyslipidaemia, diabetes mellitus, smoking, family history and obesity. Symptoms are classified as absent, typical chest pain, atypical chest pain and dyspnoea. Primary endpoints are death, major adverse cardiovascular events (cardiac death, unstable angina requiring hospitalisation, acute myocardial infarction) and shifting of cardiovascular risk category on the basis of coronary plaque burden. The secondary endpoint is coronary revascularisation. Telephone interviews and/or clinical databases are used for the follow-up. The study will be conducted on a population >1,000 patients. CONCLUSIONS: The information collected from the Prognostic Registry for Coronary Artery Disease (PRORECAD) will provide insight into the prognostic value of CTCA in addition to demographic and clinical features. The results will allow for better use and interpretation of CTCA for prognostic purposes.

Global and regional longitudinal strain assessed by two-dimensional speckle tracking echocardiography identifies early myocardial dysfunction and transmural extent of myocardial scar in patients with acute ST elevation myocardial infarction and relatively preserved LV function.

AIMS: Global and regional longitudinal strain (GLS-RLS) assessed by two-dimensional speckle tracking echocardiography (2D-STE) are considered reliable indexes of left-ventricular (LV) function and myocardial viability in chronic ischaemic patients when compared with delayed-enhanced cardiac magnetic resonance (DE-CMR). In the present study, we tested whether GLS and RLS could also identify early myocardial dysfunction and transmural extent of myocardial scar in patients with acute ST elevation myocardial infarction (STEMI) and relatively preserved LV function. METHODS AND RESULTS: Twenty STEMI patients with LVEF ≥40%, treated with PPCI within 6 h from symptoms onset, underwent DE-CMR and 2D-echocardiography for 2D-STE analysis 6 ± 2 days after STEMI. Wall motion score index (WMSI) and LV ejection fraction (LVEF) were calculated by both methods. Infarct size and transmural extent of necrosis were assessed by CMR. GLS and RLS were obtained by 2D-STE. Mean GLS of the study population was -14 ± 3.3, showing a significant correlation with both LVEF and WMSI, by CMR (r = -0.86, P = 0.001, and r = 0.80, P = 0.001, respectively) and time-to-PCI (r = 0.66, P = 0.038). A weaker correlation was found between GLS and LVEF and WMSI assessed by 2D-echo (r = -0.65, P = 0.001, and r = 0.53, P = 0.013, respectively). RLS was significantly lower in DE-segments when compared with normal myocardium (P < 0.0001). A cut-off value of RLS of -12.3% by receiver-operating characteristic (ROC) curves identified DE-segments (sensitivity 82%, specificity 78%), whereas a cut-off value of -11.5% identified transmural extent of DE (sensitivity 75%, specificity 78%). CONCLUSION: Our findings indicate that RLS and GLS evaluation provides an accurate assessment of global myocardial function and of the presence of segments with transmural extent of necrosis, with several potential clinical implications.

[Clinical indications for the use of cardiac MRI. By the SIRM Study Group on Cardiac Imaging]. / Indicazioni cliniche per l'utilizzo della cardio RM. A cura del Gruppo di lavoro della Sezione di Cardio-Radiologia della SIRM.

Cardiac magnetic resonance (CMR) is considered an useful method in the evaluation of many cardiac disorders. Based on our experience and available literature, we wrote a document as a guiding tool in the clinical use of CMR. Synthetically we describe different cardiac disorders and express for each one a classification, I to IV, depending on the significance of diagnostic information expected.

Clinical indications for cardiac computed tomography. From the Working Group of the Cardiac Radiology Section of the Italian Society of Medical Radiology (SIRM).

Cardiac computed tomography (CCT) has grown as a useful means in different clinical contexts. Technological development has progressively extended the indications for CCT while reducing the required radiation dose. Even today there is little documentation from the main international scientific societies describing the proper use and clinical indications of CCT; in particular, there are no complete guidelines. This document reflects the position of the Working Group of the Cardiac Radiology Section of the Italian Society of Radiology concerning the indications for CCT.

Utility of T2-weighted short-tau inversion recovery (STIR) sequences in cardiac MRI: an overview of clinical applications in ischaemic and non-ischaemic heart disease.

T2-weighted short-tau inversion recovery (T2w-STIR) imaging is the best approach for oedema-weighted cardiac magnetic resonance imaging (MRI), as it suppresses the signal from flowing blood and from fat and enhances sensitivity to tissue fluid. The purpose of this pictorial review is to illustrate the clinical use and application of this technique in various ischaemic and non-ischaemic conditions. In ischaemic heart disease, T2w-STIR represents the technique of choice for detecting oedema in patients with acute myocardial infarction (MI), allowing discrimination of acute and chronic injuries. Myocardial haemorrhage may also be depicted as a region of signal abnormality characterised by a central hypointense core with a peripheral hyperintense rim, presumably reflecting the presence of intracellular methaemoglobin within the necrotic area. In the acute setting, elevated T2 relaxation times in association with regional contractile dysfunction but no signs of delayed enhancement may also signify a reversible ischaemic injury without necrosis. In acute myocarditis, the distribution pattern of T2w hyperintensity may be focal in approximately 30% of patients or diffuse in the remaining 70%, and myocardial oedema may be the only marker of disease. Tissue oedema may also be observed in various other conditions, such as primary cardiomyopathies (CMP), storage disease, pulmonary hypertension and cardiac transplant rejection. T2w-STIR represents an appealing and versatile technique that can be applied in a wide variety of ischaemic and non-ischaemic conditions, allowing detection of segmental or global increase of myocardial free water content, reflecting an acute myocardial injury.

Cardiac and pericardial abnormalities on chest computed tomography: what can we see?

Radiological reporting in chest computed tomography (CT) is primarily focused on assessing pulmonary and mediastinal abnormalities, thereby tending to overlook the heart. However, incidental cardiac abnormalities are often encountered and misdiagnosed, which may potentially impact the patient's treatment or necessitate further investigation. The aim of this pictorial review is to provide a stepwise approach to assessing the heart on routine non-electrocardiographic-gated (non-ECG-gated) chest CT and describing common and less frequent cardiac abnormalities.

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 of myocardial infarction using a 64-slice MDCT scanner: correlation between infarcted region and status of territory-dependent coronary artery.

PURPOSE: This study was performed to evaluate the ability of 64-slice multidetector computed tomography (MDCT) to detect previous myocardial infarctions (MIs) in patients referred for the assessment of the coronary arteries. In patients with regional changes of left ventricular wall myocardial density, the territory-dependent coronary vessel status was examined. MATERIALS AND METHODS: We retrospectively assessed 202 consecutive patients referred for 64-slice MDCT of the coronary arteries. In all cases, detailed, clinical, serological and electrocardiograph (ECG) data were collected to identify patients with a previous diagnosis of MI. An initial qualitative evaluation of MDCT images was performed in all patients to identify areas of suspected myocardial necrosis, which were defined as regions of lower density within normally enhanced left ventricular myocardium. Thereafter, in all patients with suspected MIs, attenuation values and left ventricular wall thickness were also measured at the level of the normal myocardium and within the hypodense regions. Each MI was also assigned to the distribution territory of a coronary vessel, and morphological data were combined with MDCT angiographic findings. RESULTS: After clinical assessment, MI was found in 27 patients (six acute).; 64-slice MDCT was able to detect the presence of MI in 24/27 cases, showing sensitivity and specificity of 89% and 95%, respectively, and an overall diagnostic accuracy of 95%. Quantitative analysis showed a significant difference (p<0.01) between attenuation values of normal vs. infarcted myocardium (124.5+/-19 HU vs. 56.1+/-23 HU, respectively); wall thinning was exclusively observed in chronic MIs (p<0.01). In 23/24 detected cases, analysis of territory-dependent arteries showed findings compatible with presence of MI. CONCLUSIONS: The presence of MI is well depicted with retrospective 64-slice MDCT. The main advantage of 64-slice MDCT is that it allows to evaluate and relate the status of a vessel and its dependent myocardial region in a single exam.

Modulation of an AMPA-like glutamate receptor (SqGluR) gating by L- and D-aspartic acids.

L- and D-aspartic acids (L-Asp and D-Asp) are present in the majority of nervous systems. In phylogeny, significant levels have been reported in mollusc brains, particularly cephalopods. To examine the role of L- and D-Asp on a cephalopod receptor, we studied ligand gating of a squid glutamate receptor (SqGluR) expressed in HEK 239 (human embryonic kidney) cells. Under voltage clamp, application of L-glutamate (L-Glu; 1-30 mM), but not D-glutamate (D-Glu), or L- or D-Asp, evoked an inward current of 0.1 nA. L- or D-Asp (200 microM) applied with 20 mM L-Glu, slowed the time course of activation and inactivation of the L-Glu gated current (time constant increased from 1 s (L-Glu alone) to 3 s (D-Asp and L-Glu) and to 19 s (L-Asp and L-Glu)). Our results suggest that in molluscan systems, aspartic acid could act as a neuromodulator during glutamatergic transmission and could significantly alter synaptic integration by slowing glutamate receptor gating.

Noninvasive imaging of the coronary arteries using a 64-row multidetector CT scanner: initial clinical experience and radiation dose concerns.

PURPOSE: We present our initial clinical experience with a recently introduced 64-detector computed tomography (64-MDCT) scanner that makes use of a periodic motion of the focal spot in the longitudinal direction (z-flying focal spot), which enables it to reach a final spatial resolution of 0.4 x 0.4 x 0.4 mm(3) and a temporal resolution of 83 ms. MATERIALS AND METHODS: A total of 114 patients (108 men, six women; age range 36-77 years, mean 63.1 years) underwent retrospective electrocardiogram (ECG)-gated examination of the coronary arteries using a 64-MDCT scanner (Somatom Sensation 64, Siemens Medical Solutions, Germany). Acquisition parameters were the following: collimation 64 x 0.6 mm, 800 quality reference milliampere second (mAs), 120 kVp, 0.33-s gantry rotation time and pitch 0.2. Images were acquired in all cases after i.v. administration of 80 ml of contrast agent (Iomeron 400 mgI/dl, Bracco, Italy) + 30 ml of saline at 4 /s and delay time determined using a bolus triggering technique. Oral betablockers were administered to patients with heart rate (HR) >75 bpm. To reduce radiation exposure, an automatic exposure control system was applied in all cases to adapt tube current to patient size and anatomic shape (CARE Dose 4D, Siemens Medical Solutions, Germany). The optimal temporal window for raw data reconstruction was chosen from an initial preview of images reconstructed with different phase settings (range 0%-95% RR interval with 5% gap) at a selected anatomical level in the mid part of the right coronary artery. CT dose index volume and effective dose were quantified in all patients using dedicated software. RESULTS: Mean HR recorded during image acquisition was 65.6+/-19.2 bmp (range: 44-96 bmp), and beta-blockers were administered to 16/114 patients (14.0%). Technical adequacy was achieved in all patients but two (2/114; 1.7%). In patients with HR <60 bmp, the best reconstruction intervals were identified in the end-systolic (30%-35% of the RR interval) and end-diastolic (60%-65% of the RR interval) phases; with faster HR (>80 bmp), high image quality was observed in end-systole (30%-35% of the RR interval). Mean CT dose index (CTDI) volume was 36.53+/-8.30 mGy per patient. In comparison with a conventional examination with fixed mAs, the use of the CARE Dose 4D system provided a 33.3% CTDI volume reduction (p<0.001). Mean effective dose was 9.5+/-3.4 millisievert (mSv) per patient (range 7.1-17.7). CONCLUSIONS: The 64-MDCT scanner diagnostic performance for coronary CT angiography is further improved with better spatial and temporal resolution and faster scan times; besides, initial clinical results are promising. The use of dose-reducing acquisition techniques is mandatory to limit radiation exposure to the patient.

Noninvasive assessment of coronary artery stenoses by multidetector-row spiral computed tomography: comparison with conventional angiography.

BACKGROUND: Coronary artery disease (CAD) is the most common cause of hospitalization and mortality in many industrialized countries. We analysed the diagnostic accuracy of multi-detector row spiral computed tomography (MDCT) in determining mid- to high-grade coronary artery stenoses (> 50%). METHODS: Sixty-nine patients with suspected CAD were referred to MDCT coronary angiography. Patients with a heart rate above 60 bpm received 20-40 mg propranol before the scan. The left main (LM), the left anterior descending artery (LAD), the first diagonal branch (D1), the right coronary artery (RCA) and the proximal tract of the circumflex artery (LCX) were independently evaluated by two blinded observers and screened for > 50% stenoses. The mean values of MDCT coronary narrowings assessed by two observers were compared to quantitative coronary angiography. RESULTS: MDCT correctly detected 95 of 123 coronary lesions (sensitivity 77.2%) and absence of stenoses was correctly identified in 388 of 426 segments (specificity 91%). The sensitivity for the LM, LAD, RCA and the proximal tract of LCX was 100%, 86.5%, 69.8% and 80% respectively. Classification of patients as having 1-vessel, 2-vessels, 3-vessels or left main disease was accurate in 75.4% (46/61) of patients. CONCLUSIONS: MDCT technology, combined with heart rate control, allows reliable noninvasive detection of hemodynamically significant CAD.

Magnetic resonance imaging in the evaluation of the pericardium. A pictorial essay.

Magnetic resonance (MR) is an ideal technique for the evaluation of the pericardium since it enables the combination of high resolution anatomical images of the pericardial layers with functional information concerning the impact of pathology on diastolic heart function and cardiac filling in particular. In comparison with echocardiography, which remains the first choice technique for the study of the pericardium, MR provides larger fields of view allowing the visualisation of the entire chest, higher spatial and contrast resolution and greater reproducibility. The technique becomes particularly useful when ultrasound imaging does not provide adequate diagnostic information or requires further characterisation; ''non-echoic'' patients, loculated pericardial effusions, focal thickening of the layers and pericardial masses are usually better assessed with MR. The method also provides valuable diagnostic information for establishing the diagnosis of constrictive pericarditis and to differentiate this condition from restrictive cardiomyopathy. The aim of this paper is to present the role of MR imaging in the assessment of a patient with suspected pericardial disease, and discuss the MR technique, anatomy and the main pathological conditions.

Reemplazo total de cadera: veinticinco años de experiencia

Evaluamos la experiencia de 25 años, realizada durante el período 1969-1994, en la cirugía con reemplazo total de cadera, utilizándose mayormente técnica y prótesis de Charnley, seleccionando para el estudio 1197 casos