Prognostic value of CT myocardial perfusion imaging and CT-derived fractional flow reserve for major adverse cardiac events in patients with coronary artery disease.

OBJECTIVES: The purpose of this study was to analyze the prognostic value of dynamic CT perfusion imaging (CTP) and CT derived fractional flow reserve (CT-FFR) for major adverse cardiac events (MACE). METHODS: 81 patients from 4 institutions underwent coronary computed tomography angiography (CCTA) with dynamic CTP imaging and CT-FFR analysis. Patients were followed-up at 6, 12, and 18 months after imaging. MACE were defined as cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, or revascularization. CT-FFR was computed for each major coronary artery using an artificial intelligence-based application. CTP studies were analyzed per vessel territory using an index myocardial blood flow, the ratio between territory and global MBF. The prognostic value of CCTA, CT-FFR, and CTP was investigated with a univariate and multivariate Cox proportional hazards regression model. RESULTS: 243 vessels in 81 patients were interrogated by CCTA with CT-FFR and 243 vessel territories (1296 segments) were evaluated with dynamic CTP imaging. Of the 81 patients, 25 (31%) experienced MACE during follow-up. In univariate analysis, a positive index-MBF resulted in the largest risk for MACE (HR 11.4) compared to CCTA (HR 2.6) and CT-FFR (HR 4.6). In multivariate analysis, including clinical factors, CCTA, CT-FFR, and index-MBF, only index-MBF significantly contributed to the risk of MACE (HR 10.1), unlike CCTA (HR 1.2) and CT-FFR (HR 2.2). CONCLUSION: Our study provides initial evidence that dynamic CTP alone has the highest prognostic value for MACE compared to CCTA and CT-FFR individually or a combination of the three, independent of clinical risk factors.

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.

Diffusion-weighted magnetic resonance imaging in locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy.

PURPOSE: To analyze diffusion-weighted magnetic resonance imaging (DW-MRI) for treatment response assessment in locally advanced rectal cancer (LARC). PATIENTS AND METHODS: Patients with histologically proven rectal adenocarcinoma, stage II-III disease, were enrolled and underwent surgery following neoadjuvant chemoradiotherapy (nCRT). All patients were referred for a DW-MRI protocol on a 3 Tesla MR-system, consisting of axial T2-weighted and DWI sequences prior (I), during (II) and after (III) nCRT. Corresponding apparent diffusion coefficient (ADC) values were calculated. RESULTS: Between February 2011 and June 2015, 37 patients participated in the study. All patients completed programmed treatment. Overall, 11 patients (29.7%) had pathologic complete response (pCR). No correlation between the mean pre- (ADC-I), during (ADC-II), post- (ADC-III) ADC and the reduction in tumor size after nCRT was recorded. No substantial difference in the ADC distribution was found between pCR and no-pCR patients. The ADC-II level significantly increased in the pCR cases (T = 1.675; p < 0.05). CONCLUSION: ADC value could be useful for discriminating between the pCR patients and the no-pCR patients. Further studies are necessary to identify the optimal MRI parameters combination to predict tumor response to nCRT. It is hoped that these data will provide the basis for a more solid scientific evidence.

Intra-individual comparison of CAIPIRINHA VIBE technique with conventional VIBE sequences in contrast-enhanced MRI of focal liver lesions.

PURPOSE: To evaluate the impact of controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA) volume interpolated breath-hold examination (VIBE) magnetic resonance imaging (MRI) technique on image quality, reader confidence, and inter-observer agreement for the assessment of focal liver lesions in comparison with the standard VIBE approach. MATERIAL AND METHODS: In this IRB-approved intra-individual comparison study, abdominal arterial and portal-venous contrast-enhanced MRI studies were retrospectively analyzed in 38 patients with malignant liver lesions. Each patient underwent both CAIPIRINHA and conventional VIBE 3T MRI within 3 months, showing stable disease. Images were evaluated using 5-point rating scales by two blinded radiologists with more than 20 and 5 years of experience in MRI, respectively. Readers scored dignity of liver lesions and assessed which liver segments were affected by malignancy (ranging from 1=definitely benign/not affected to 5=definitely malignant/affected by malignancy). Readers also rated overall image quality, sharpness of intrahepatic veins, and diagnostic confidence (ranging from 1=poor to 5=excellent). RESULTS: Reviewers achieved a higher inter-observer reliability using CAIPIRINHA when they reported which liver segments were affected by malignancy compared to traditional VIBE series (κ=0.62 and 0.54, respectively, p<0.05). Similarly, CAIPIRINHA showed a slightly higher inter-rater agreement for the dignity of focal liver lesions versus the standard VIBE images (κ=0.50 and 0.49, respectively, p<0.05). CAIPIRINHA series also scored higher in comparison to standard VIBE sequences (mean scores: image quality, 4.2 and 3.5; sharpness of intrahepatic vessels, 3.8 and 3.2, respectively, p<0.05) for both reviewers and allowed for higher subjective diagnostic confidence (ratings, 3.8 and 3.2, respectively, p<0.05). CONCLUSION: Compared to the standard VIBE approach, CAIPIRINHA VIBE technique provides improved image quality and sharpness of intrahepatic veins, as well as higher diagnostic confidence. Additionally, this technique allows for higher inter-observer agreement when reporting focal liver lesions for both dignity and allocation.

Cerebral CTA with Low Tube Voltage and Low Contrast Material Volume for Detection of Intracranial Aneurysms.

BACKGROUND AND PURPOSE: Multidetector row CTA has become the primary imaging technique for detecting intracranial aneurysms. Technical progress enables the use of cerebral CTA with lower radiation doses and contrast media. We evaluated the diagnostic accuracy of 80-kV(peak) cerebral CTA with 30 mL of contrast agent for detecting intracranial aneurysms. MATERIALS AND METHODS: Two hundred four patients were randomly divided into 2 groups. Patients in group A (n = 102) underwent 80-kVp CTA with 30 mL of contrast agent, while patients in group B (n = 102) underwent conventional CTA (120 kVp, 60 mL of contrast agent). All patients underwent DSA. Image quality, diagnostic accuracy, and radiation dose between the 2 groups were compared. RESULTS: Diagnostic image quality was obtained in 100 and 99 patients in groups A and B, respectively (P = .65). With DSA as reference standard, diagnostic accuracy on a per-aneurysm basis was 89.9% for group A and 93.9% for group B. For evaluating smaller aneurysms (<3 mm), the diagnostic accuracy of groups A and B was 86.3% and 90.8%, respectively. There was no difference in diagnostic accuracy between each CTA group and DSA (all, P > .05) or between the 2 CTA groups (all, P > .05). The effective dose in group A was reduced by 72.7% compared with group B. CONCLUSIONS: In detecting intracranial aneurysms with substantial radiation dose and contrast agent reduction, 80-kVp/30-mL contrast CTA provides the same diagnostic accuracy as conventional CTA.

Cardiac CT for myocardial ischaemia detection and characterization--comparative analysis.

The assessment of patients presenting with symptoms of myocardial ischaemia remains one of the most common and challenging clinical scenarios faced by physicians. Current imaging modalities are capable of three-dimensional, functional and anatomical views of the heart and as such offer a unique contribution to understanding and managing the pathology involved. Evidence has accumulated that visual anatomical coronary evaluation does not adequately predict haemodynamic relevance and should be complemented by physiological evaluation, highlighting the importance of functional assessment. Technical advances in CT technology over the past decade have progressively moved cardiac CT imaging into the clinical workflow. In addition to anatomical evaluation, cardiac CT is capable of providing myocardial perfusion parameters. A variety of CT techniques can be used to assess the myocardial perfusion. The single energy first-pass CT and dual energy first-pass CT allow static assessment of myocardial blood pool. Dynamic cardiac CT imaging allows quantification of myocardial perfusion through time-resolved attenuation data. CT-based myocardial perfusion imaging (MPI) is showing promising diagnostic accuracy compared with the current reference modalities. The aim of this review is to present currently available myocardial perfusion techniques with a focus on CT imaging in light of recent clinical investigations. This article provides a comprehensive overview of currently available CT approaches of static and dynamic MPI and presents the results of corresponding clinical trials.

Role of imaging in the management of endometriosis.

The imaging techniques have a fundamental role in the diagnosis of endometriosis. Ovarian endometriosis (endometrioma) and deep endometriosis can be recognized using transvaginal ultrasound and/or magnetic resonance imaging (MRI). Although transvaginal ultrasound is the first choice of imaging modality when investigating women with pelvic pain, MRI have a role for the wider field of visions. The reproducibility of both techniques has been investigated. The three-dimensional ultrasonography has been proposed. Also studies regarding unusual localizations are reported in the literature. New insights are present about the role of imaging in the detection of the malignant transformations. This review summarizes the current evidence on the diagnostic accuracy of these two techniques in the pre-surgical assessment of endometriosis.

Gallbladder and muscular endometriosis: a case report.

A 55-year-old woman referred to Radiology Department, with abdominal mass and chronic indefinite and vague abdominal pain, most severe in right hypochondrium and accentuated during menstruation. A history of two cesarean sections was revealed. The patient underwent an ultrasound and Computed Tomography with intravenous contrast media revealing the presence of gallbladder and abdominal wall hyperenhancing masses. Finally, Magnetic Resonance study with intravenous administration of paramagnetic contrast media confirmed the involvement of gallbladder by a solid tissue and the presence of a solid nodule on the abdominal wall. Considering imaging features and the contrast enhancement of the nodules, the patient was sent to surgery. Surgical removal of both gallbladder and abdominal solid implant was performed and histology confirmed the diagnosis of gallbladder and abdominal wall endometriosis.

Dual source CT: state of the art in the depiction of coronary arteries anatomy, anatomical variants and myocardial segments.

Cardiovascular disease is the leading cause of death in adults in western countries. Coronary angiography remains the gold standard for the diagnosis of coronary artery disease, a procedure that carries risks. Nowadays, a significant number of the coronary angiographies performed every year are only diagnostic. Multidetector computed tomography (MDCT) allows non-invasive evaluation of coronary arteries. It is a continuously developing technique, and actually the top technology is represented by Dual Source CT. This scanner of new conception permits an improvement in image quality, and visualization of distal vessels and small collateral branches. The aim of our work is to illustrate the actual state of the art in non-invasive coronary arteries evaluation represented by Dual Source CT, presenting images of coronary arteries normal anatomy, anatomical variants and myocardial segment.

Accuracy of different reconstruction intervals to quantify left ventricular function and mass in cardiac computed tomography examinations.

PURPOSE: To compare the accuracy of cardiac dual-source CT (DSCT) reconstructions obtained at 5% and 10% of the cardiac cycle and MRI for quantifying global left ventricular (LV) function and mass in heart transplant recipients. MATERIAL AND METHODS: We prospectively included 23 heart transplant recipients (21 male, mean age 60±11.7 years) who underwent cardiac DSCT and MRI examinations. We compared LV parameters on cardiac DSCT reconstructions obtained at 5% (0%-95%) and 10% (0%-90%) intervals of the cardiac cycle and on double-oblique short-axis MR images. We determined ejection fraction (EF), end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), and myocardial mass using commercially available semiautomated segmentation analysis software for DSCT datasets and conventional manual contour tracing for MR studies. RESULTS: Using different reconstruction intervals to quantify LV parameters at DSCT resulted in non-significant differences (P>.05). Compared to MRI, DSCT slightly overestimated LV-EDV, ESV, and mass when both 5% (11.5±25.1ml, 6.8±10.9ml, and 28.3±21.6g, respectively) and 10% (mean difference 15.3±26.3ml, 7.4±11.5ml, and 29.3±18.7g, respectively) reconstruction intervals were used. DSCT and MRI estimates of EF and SV were not significantly different. CONCLUSION: In heart transplant recipients, DSCT allows reliable quantification of LV function and mass compared with MRI, even using 10% interval reconstructions.

Dual-source CT coronary angiography: prospective versus retrospective acquisition technique.

PURPOSE: The aim of our work was to compare image quality and radiation dose in a group of patients who underwent cardiac dual-source computed tomography (DSCT) with prospective electrocardiographic (ECG) gating with those of a control group studied with retrospective gating. MATERIALS AND METHODS: Sixty patients were randomly assigned to two groups of 30 individuals each. Patients with heart rates >70 bpm and body mass index (BMI) >30 kg/m(2) were excluded. Group A was examined with prospective ECG gating and group B with retrospective gating. The dose-length product (DLP) was recorded to calculate the radiation dose, whereas the effective dose was normalised to a standard 12-cm scan of the heart. RESULTS: Applying the best reconstruction interval, 98.6% of segments in the prospective group and 99.3% in the retrospective group were diagnostic. No significant difference (p>0.05) in image quality was observed between groups. Mean normalised radiation dose was 4.91 ± 0.4 mSv in the prospective-gating group and 14.62 mSv ± 4.36 in the retrospective-gating group (p<0.01). CONCLUSIONS: Coronary CT with prospective ECG gating, a standard feature on new scanners, allows for a significant reduction in radiation dose without causing any significant decrease in image quality or in the number of segments assessed. The prospective technique is thus recommended for patients with heart rates £70 bpm and BMI £30 kg/m(2).

Preliminary experience with abdominal dual-energy CT (DECT): true versus virtual nonenhanced images of the liver.

PURPOSE: The aim of this work was to compare the quality and noise of true non-enhanced (TNE) and virtual non-enhanced (VNE) images in patients undergoing dual-energy computed tomography (DECT) of the liver. MATERIALS AND METHODS: Twenty consecutive patients (mean age 54.7±19.9 years) prospectively underwent abdominal DECT to assess the liver using a triphasic protocol consisting of precontrast, arterial-phase and portal-phase acquisitions. Exclusion criteria were allergy to iodinated contrast material, impaired renal function and a body mass index (BMI) >35 kg/m(2). The DE portal-phase acquisition was performed with automatic dose modulation (CARE Dose 4D). Nonionic iodinated contrast material (Iomeron 400) was administered at 0.625 gI/kg with a flow rate of 3.5 ml/s. Axial VNE images were reconstructed based on the portal data set using a collimation and an increment of 5 mm and were compared with TNE images reconstructed with the same parameters. The average image quality and noise were analysed by two radiologists in separate reading sessions. RESULTS: No statistically significant difference (p>0.05) in image quality was observed between VNE (4.00±0.85) and TNE images (4.35±0.58). A sufficient diagnostic quality was found in 95.0% (19/20) of VNE images and in 100% of TNE images. No statistically significant difference (p<0.05) was observed in the average image noise of VNE (9.5±0.7) and TNE (12.3±1.1) images. CONCLUSIONS: Abdominal DECT allows acquisition of liver VNE images with similar image quality and lower noise than TNE. Nevertheless, a few technical limitations related to the small field of view of the second detector in patients with a high BMI and heterogeneous iodine subtraction restrict the application of this technique to selected patients only.

Preoperative coronary risk assessment with dual-source CT in patients undergoing noncoronary cardiac surgery.

PURPOSE: The aim of our work was to assess the role of dual-source computed tomography (DSCT) in the preoperative evaluation of coronary artery disease in patients scheduled for noncoronary cardiac surgery. MATERIALS AND METHODS: One hundred patients were prospectively evaluated. Patients negative for coronary disease at DSCT (n=81) underwent surgery without coronary angiography. Patients positive for significant lesions or with nondiagnostic image quality due to artefacts or severe calcifications underwent coronary angiography (n=19) and were excluded from the study. In patients who underwent surgery with only a DSCT diagnosis, we evaluated the frequency of major adverse cardiac events (MACEs) during the perioperative period and at 3 months follow-up. RESULTS: No MACEs were recorded during the perioperative period; three noncardiac complications (one surgical revision for bleeding, one cardiac tamponade and one respiratory insufficiency) and one death related to severe respiratory insufficiency were observed. None of the 80 patients had MACEs during the 3-month follow-up period. CONCLUSIONS: Coronary evaluation with DSCT is able to rule out the presence of coronary disease in patients scheduled for cardiac surgery, without the need for coronary angiography confirmation. Patients with significant stenosis or nondiagnostic image quality should be referred for coronary angiography.

[Global evaluation of the heart in heart transplant recipients using dual-source computed tomography]. / Valoración global del corazón en el paciente con transplante cardiaco mediante tomografía computarizada de doble fuente.

In routine clinical practice surveillance of heart transplant recipients is usually performed using echocardiography and conventional coronary angiography. The latter permits diagnosis and follow-up of coronary allograft vasculopathy. However, this procedure is invasive and is not free of complications. Conventional multislice computed tomography (MSCT) has been shown to be a useful non-invasive tool for ruling out coronary artery disease and evaluating cardiac function. However, due to its limited temporal resolution betablocker administration is required, and its usefulness in certain patient populations with restricted response to this medication, such as heart transplant recipients, may therefore be limited. Dual-source CT (DSCT) allows evaluation of the coronary arteries in all individuals independent of their heart rate. In the case presented here, we demonstrate that DSCT may be useful for evaluating cardiac function and ruling out coronary allograft vasculopathy in heart transplant recipients.

Global cardiac evaluation without heart rate control: preliminary experience with dual source CT (DSCT).

AIM: The aim of this work was to assess the role of dual source computed tomography (DSCT) in global cardiac evaluation without heart rate control, assessing the effect of average heart rate on coronary image quality, optimal reconstruction interval, ventricular function, and evaluation of left chamber valves. METHODS: Fifteen consecutive patients under-went coronary CT angiography. For coronary evaluation, data sets were reconstructed in 5% steps from 30% to 80% of the RR interval. For the assessment of cardiac function, image were reconstructed with a slice thickness of 2.0 mm and 2.0 mm increment, at 10% steps from 0% to 90% of the RR interval. Two blinded independent readers assessed the image quality of the coronary arteries and left chamber valves. RESULTS: The mean heart rate during the scan was 73+/-11.8 bpm (range 56-97). At the best reconstruction interval excellent diagnostic image quality (score 4) was achieved in 95.5% (43/45) of coronary arteries. Excellent inter-observer agreement was observed for image quality rating (k=0.82). No significant correlation was found between the average heart rate and the mean quality scores (rho=0.29). Comparison of image quality of the coronary arteries in systolic and diastolic reconstructions in each patient showed no statistically significant differences. CONCLUSION: DSCT is an excellent technique for global cardiac imaging, as it allows to obtain coronary arteries of excellent quality and evaluate ventricular function and valvular area independent of the heart rate.

Anatomical variations of the coeliac trunk and the mesenteric arteries evaluated with 64-row CT angiography.

PURPOSE: This study was undertaken to evaluate the accuracy of 64-row computed tomography angiography (CTA) in the study of vascular anatomy by assessing the incidence of anatomical variations of the origin of the coeliac trunk, mesenteric arteries and collateral branches. MATERIALS AND METHODS: Sixty patients were evaluated with 64-row CTA (VCT, General Electric Healthcare, Milwaukee, WI, USA) with a collimation of 0.625 mm after the injection of iodinated nonionic contrast material (4 ml/s). Exclusion criteria were the presence of any pathological condition likely to affect normal vascular anatomy. RESULTS: The coeliac trunk had a normal trifurcation in 56.7% of cases. The common hepatic artery was normal in 60% of patients. The inferior pancreaticoduodenal arteries were either absent or not assessable in 8.3% of cases and there was a double trunk in 5%, a common trunk in 83.3% and a single vessel in 3.3%. The number of jejunal and ileal arteries ranged from a minimum of six to a maximum of 13 (mean value 8.7+/-1.34). The Riolan arcade was assessable in 31.7% and developed in 68.4% of these. CONCLUSIONS: The 64-row CTA enables visualisation of small vessels and accessory arteries that are difficult to identify with other techniques. The technique's high sensitivity allowed us to observe that the prevalence of vascular abnormalities is higher than that reported in the literature.