Prognostic value of myocardial deformation parameters for outcome prediction in tetralogy of Fallot.

BACKGROUND: The prognostic value of myocardial deformation parameters in adults with repaired tetralogy of Fallot (rTOF) has not been well-elucidated. We therefore aimed to explore myocardial deformation parameters for outcome prediction in adults with rTOF using cardiovascular magnetic resonance imaging (CMR). METHODS: Adults with rTOF and at least moderate pulmonary regurgitation were identified from an institutional prospective CMR registry. Left ventricular (LV) and right ventricular (RV) global strains were recorded in longitudinal (GLS), circumferential (GCS), and radial (GRS) directions. Major adverse cardiovascular events (MACE) were defined as a composite of mortality, resuscitated sudden death, sustained ventricular tachycardia (>30 seconds), or heart failure (hospital admission >24 hours). In patients with pulmonary valve replacement (PVR), pre- and post-PVR CMR studies were analyzed to assess for predictors of complete RV reverse remodeling, defined as indexed RV end-diastolic volume (RVEDVi) <110 mL/m2. Logistic regression models were used to estimate the odds ratio (OR) per unit change in absolute strain value associated with clinical outcomes and receiver operator characteristic curves were constructed with area under the curve (AUC) for select CMR variables. RESULTS: We included 307 patients (age 35 ± 13 years, 59% (180/307) male). During 6.1 years (3.3-8.8) of follow-up, PVR was performed in 142 (46%) and MACE occurred in 31 (10%). On univariate analysis, baseline biventricular ejection fraction (EF), mass, and all strain parameters were associated with MACE. After adjustment for LVEF, only LV-GLS remained independently predictive of MACE (OR 0.822 [0.693-0.976] p = 0.025). Receiver operator curves identified an absolute LV-GLS value less than 15 and LVEF less than 51% as thresholds for MACE prediction (AUC 0.759 [0.655-0.840] and 0.720 [0.608-0.810]). After adjusting for baseline RVEDVi, RV-GCS (OR 1.323 [1.094-1.600] p = 0.004), LV-GCS (OR 1.276 [1.029-1.582] p = 0.027) and LV-GRS (OR 1.101 [1.0210-1.200], p = 0.028) were independent predictors of complete remodeling post-PVR remodeling. CONCLUSION: Biventricular strain parameters predict clinical outcomes and post-PVR remodeling in rTOF. Further study will be necessary to establish the role of myocardial deformation parameters in clinical practice.

Comparing Cardiac Mechanics and Myocardial Fibrosis in DBD and DCD Heart Transplant Recipients.

BACKGROUND: Heart transplantation (HTx) after donation after circulatory death (DCD) is an expanding practice but is associated with increased warm ischemic time. The impact of DCD HTx on cardiac mechanics and myocardial fibrosis has not been reported. We aimed to compare cardiac mechanics and myocardial fibrosis using cardiovascular magnetic resonance (CMR) imaging in donation after brain death (DBD) and DCD HTx recipients and healthy controls. METHODS AND RESULTS: Consecutive HTx recipients between March 2015 and March 2021 who underwent routine surveillance CMR imaging were included. Cardiac mechanics were assessed using CMR feature tracking to compute global longitudinal strain, global circumferential strain, and right ventricular free-wall longitudinal myocardial strain. Fibrosis was assessed using late gadolinium enhancement imaging and estimation of extracellular volume. There were 82 (DBD n = 42, DCD n = 40) HTx recipients (aged 53 years, interquartile range 41-59 years, 24% female) who underwent CMR imaging at median of 9 months (interquartile range 6-14 months) after transplantation. HTx recipients had increased extracellular volume (29.7 ± 3.6%) compared with normal ranges (25.9%, interquartile range 25.4-26.5). Myocardial strain was impaired after transplantation compared with controls (global longitudinal strain -12.6 ± 3.1% vs -17.2 ± 1.8%, P < .0001; global circumferential strain -16.9 ± 3.1% vs -19.2 ± 2.0%, P = .002; right ventricular free-wall longitudinal strain -15.7 ± 4.5% vs -21.6 ± 4.7%, P < .0001). There were no differences in fibrosis burden (extracellular volume 30.6 ± 4.4% vs 29.2 ± 3.2%; P = .39) or cardiac mechanics (global longitudinal strain -13.1 ± 3.0% vs -12.1 ± 3.1%, P = .14; global circumferential strain -17.3 ± 2.9% vs -16.6 ± 3.1%, P = .27; right ventricular free-wall longitudinal strain -15.9 ± 4.9% vs -15.5 ± 4.1%, P = .71) between DCD and DBD HTx. CONCLUSIONS: HTx recipients have impaired cardiac mechanics compared with controls, with increased myocardial fibrosis. There were no differences in early CMR imaging characteristics between DBD and DCD heart transplants, providing further evidence that DCD and DBD HTx outcomes are comparable.

Lung ultrasound B-lines in systemic sclerosis: cut-off values and methodological indications for interstitial lung disease screening.

OBJECTIVES: Lung ultrasound (LUS), through assessment of B-lines and pleural line alterations, is able to evaluate interstitial lung disease (ILD), a frequent complication of SSc. Different scanning schemes and counting methods have been proposed but no clear cut-off values have been indicated for screening. We aimed to evaluate the accuracy of different LUS methodological approaches to detect ILD compared with high-resolution CT (HRCT) as the gold standard. METHODS: Sixty-nine SSc patients underwent LUS and chest HRCT on the same day. Both exams were scored by expert readers. The accuracy of different scanning schemes and counting methods was assessed and clinical and functional data were compared with imaging findings. RESULTS: B-lines were more numerous in patients with the diffuse skin subset and Scl70 autoantibody positivity. The number of B-lines correlated with the Scleroderma Lung Study (SLS) I HRCT score (R = 0.754, P < 0.0001). A total of >10 B-lines on the whole chest or >1 B-line on the postero-basal chest showed 97% sensitivity for detecting even very early ILD signs (corresponding to an SLS I score of 1). Sensitivity increased to 100% when pleural line alterations were included in the analysis. CONCLUSIONS: LUS has a very high sensitivity in detecting SSc-related ILD. A cut-off value of >10 B-lines on the whole chest or >1 B-line on the postero-basal chest can be used for the screening of SSc-ILD. Assessing only the postero-basal chest seems to be mostly effective, combining high sensitivity with a less time-consuming approach.

High-resolution dynamic CE-MRA of the thorax enabled by iterative TWIST reconstruction.

PURPOSE: To evaluate the clinical benefit of using a new iterative reconstruction technique fully integrated on a standard clinical scanner and reconstruction system using a TWIST acquisition for high-resolution dynamic three-dimensional contrast-enhanced MR angiography (CE-MRA). METHODS: Low-dose, high-resolution TWIST datasets of 11 patients were reconstructed using both standard GRAPPA-based reconstruction for reference and iterative reconstruction, which reduces the temporal footprint of reconstructed images. Image quality of both techniques was assessed by two experienced readers, as well as quantitatively evaluated using a time-signal curve analysis. RESULTS: Image quality scores consistently and significantly improved by using iterative reconstruction compared with the standard approach. Most notably, the delineation of small to mid-size vasculature improved from a mean Likert score between "nondiagnostic" and "poor" for standard to between "good" and "excellent" for iterative reconstruction. The full width at half maximum of the contrast agent bolus computed from the time-signal curve was also reduced by iterative reconstruction, allowing for more precise bolus timing. CONCLUSION: Iterative reconstruction can substantially improve high-resolution dynamic CE-MRA image quality, most notably in small to mid-size vasculature. Dynamic CE-MRA with iterative reconstruction could become an alternative to conventional static 3D CE-MRA, thus simplifying the clinical workflow. Magn Reson Med 77:833-840, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Impact of model-based iterative reconstruction on low-contrast lesion detection and image quality in abdominal CT: a 12-reader-based comparative phantom study with filtered back projection at different tube voltages.

OBJECTIVES: To evaluate the impact of model-based iterative reconstruction (MBIR) on image quality and low-contrast lesion detection compared with filtered back projection (FBP) in abdominal computed tomography (CT) of simulated medium and large patients at different tube voltages. METHODS: A phantom with 45 hypoattenuating lesions was placed in two water containers and scanned at 70, 80, 100, and 120 kVp. The 120-kVp protocol served as reference, and the volume CT dose index (CTDIvol) was kept constant for all protocols. The datasets were reconstructed with MBIR and FBP. Image noise and contrast-to-noise-ratio (CNR) were assessed. Low-contrast lesion detectability was evaluated by 12 radiologists. RESULTS: MBIR decreased the image noise by 24% and 27%, and increased the CNR by 30% and 29% for the medium and large phantoms, respectively. Lower tube voltages increased the CNR by 58%, 46%, and 16% at 70, 80, and 100 kVp, respectively, compared with 120 kVp in the medium phantom and by 9%, 18% and 12% in the large phantom. No significant difference in lesion detection rate was observed (medium: 79-82%; large: 57-65%; P > 0.37). CONCLUSIONS: Although MBIR improved quantitative image quality compared with FBP, it did not result in increased low-contrast lesion detection in abdominal CT at different tube voltages in simulated medium and large patients. KEY POINTS: • MBIR improved quantitative image quality but not lesion detection compared with FBP. • Increased CNR by low tube voltages did not improve lesion detection. • Changes in image noise and CNR do not directly influence diagnostic accuracy.

The role of biomechanical anatomical modeling via computed tomography for identification of restrictive allograft syndrome.

Chronic lung allograft dysfunction (CLAD) reduces long-term graft survival. It is important to distinguish CLAD subtypes: bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome (RAS) as RAS has a worse prognosis and accurate subtyping could facilitate targeted treatments. However, the current diagnosis of CLAD subtypes is based on pulmonary function test (PFT) results that reflect global estimates of lung function; anatomical modeling based on computed tomography (CT) has the potential to provide detailed analysis of global and regional lung function. The purpose of this study is to evaluate the utility of CT-based anatomical modeling for the identification of RAS. This retrospective study included 51 patients (CLAD: 17 BOS and 17 RAS, control: 17 No-CLAD). CT data were assessed using a biomechanical model-based platform (MORFEUS) to characterize changes in lung deformation between baseline and disease onset. Lung deformation demonstrated high sensitivity and specificity (>80%) in differentiating RAS from BOS (P<.0001) and No-CLAD (P<.0001). There were matching radiological reading and inward deformation abnormalities in 79% of lung sections in patients with RAS. Anatomical modeling is complementary to conventional assessment in the diagnosis of RAS and potentially provides quantitative data that can help in the characterization and detailed assessment of heterogeneous lung parenchymal disease.

Organ-based tube current modulation in a clinical context: Dose reduction may be largely overestimated in breast tissue.

OBJECTIVES: Organ-based tube current modulation aims to reduce exposure to radiosensitive organs like the breasts by considering their anatomical location and altering tube current during rotation. Former phantom studies demonstrated a dose reduction of 20-37 %. Our study aimed to estimate the potential of dose reduction with this technique in relation to the actual location of breast tissue in a large clinical cohort. METHODS: A 1-year cohort of chest CTs of females (N=1,263) was retrospectively evaluated. To estimate the relative dose effect, breast location was analysed by measuring the angle range of glandular tissue within the different dose zones. Relative exposure compared with constant tube current was calculated. Descriptive statistics and Wilcoxon-test were applied. RESULTS: Only 63 % of angle range of glandular breast tissue was found inside the reduced dose zone. The estimated mean relative dose reduction was lower than observed in former phantom studies(16 % vs. 20-37 %) but still significant compared to constant tube current (p<0.0001). CONCLUSIONS: Although organ-based tube current modulation results in a significant reduction of breast exposure compared to non-modulated irradiation, the technique cannot unfold its full potential, because breast tissue is often located outside the reduced dose zone, resulting in significantly lower dose reduction than expected. KEY POINTS: • OBTCM results in significant dose reduction compared to constant tube current scans. • A substantial portion of glandular tissue lies outside the reduced dose zone. • Potential dose reduction using organ-based tube current modulation may be overestimated.

Effects of slice orientation on reproducibility of sequential assessment of right ventricular volumes and ejection fraction: short-axis vs transverse SSFP cine cardiovascular magnetic resonance.

BACKGROUND: Test-retest reproducibility is of utmost importance in follow-up of right ventricular (RV) volumes and function; optimal slice orientation though is not yet known. We compared test-retest reproducibility and intra-/inter-observer variability of right ventricular (RV) volumes and function assessed with short-axis and transverse cardiovascular magnetic resonance (CMR). METHODS: Eighteen volunteers underwent cine CMR for RV assessment obtaining ventricular coverage in short-axis and transverse slice orientation. Additional 2D phase contrast flow imaging of the main pulmonary artery (MPA) was performed. After complete repositioning repeat acquisitions were performed. Data sets were contoured by two blinded observers. Statistical analysis included Student's t-test, Bland-Altman plots, intra-class correlation coefficient (ICC) and 2-way ANOVA, SEM and minimal detectable difference calculations. RESULTS: Heart rates (65.0 ± 7.4 vs. 67.6 ± 9.9 bpm; P = 0.1) and MPA flow (89.8 ± 16.6 vs. 87.2 ± 14.9 mL; P = 0.1) did not differ between imaging sessions. EDV and ESV demonstrated an inter-study bias of 0.4 %[-9.5 %,10.3 %] and 2.1 %[-12.3 %,16.4 %] for short-axis and 1.1 %[-7.3 %,9.4 %] and 0.8 %[-16.0 %,17.6 %] for transverse orientation, respectively. There was no significant interaction between imaging orientation and interstudy reproducibility (p = 0.395-0.824), intra-observer variability (p = 0.726-0.862) or inter-observer variability (p = 0.447-0.706) by 2-way ANOVA. Inter-observer agreement by ICC was greater for short axis versus transverse orientation for all parameters (0.769-0.986 vs. 0.625-0.983, respectively). Minimal detectable differences for short axis and transverse orientations were 10.1 mL/11.5 mL for EDV, 8.3 mL/8.4 mL for ESV and 4.1 % vs. 4.7 % for EF, respectively. CONCLUSION: Short-axis and transverse orientation both provide reliable and reproducible measures for follow-up of RV volumes and global function. Therefore, additional transverse SSFP cine CMR may not necessarily be required if performed for the sole purpose of quantitative volumetric RV assessment.

Diagnostic Accuracy in Detecting Fungal Infection with Ultra-Low-Dose Computed Tomography (ULD-CT) Using Filtered Back Projection (FBP) Technique in Immunocompromised Patients.

Purpose: To compare the accuracy of ultra-low-dose (uLDCT) to standard-of-care low-dose chest CT (LDCT) in the detection of fungal infection in immunocompromised (IC) patients. Method and Materials: One hundred IC patients had paired chest CT scans performed with LDCT followed by uLDCT. The images were independently reviewed by three chest radiologists who assessed the image quality (IQ), diagnostic confidence, and detection of major (macro nodules, halo sign, cavitation, consolidation) and minor (4-10 mm nodules, ground-glass opacity) criteria for fungal disease using a five-point Likert score. Discrepant findings were adjudicated by a fourth chest radiologist. Box-whisker plots were used to analyze IQ and diagnostic confidence. Inter-rater reliability was assessed using interclass correlation coefficients (ICCs). The statistical difference between LDCT and uLDCT results was assessed using Wilcoxon paired test. Results: Lung reconstructions had IQ and diagnostic confidence scores (mean ± std) of 4.52 ± 0.47 and 4.63 ± 0.51 for LDCT and 3.85 ± 0.77 and 4.01 ± 0.88 for uLDCT. The images were clinically acceptable except for uLDCT in obese patients (BMI ≥ 30 kg/m2), which had an IQ ranking from poor to excellent (scores 1 to 5). The accuracy in detecting major and minor radiological findings with uLDCT was 96% and 84% for all the patients. The inter-rater agreements were either moderate, good, or excellent, with ICC values of 0.51-0.96. There was no significant statistical difference between the uLDCT and LDCT ICC values (p = 0.25). The effective dose for uLDCT was one quarter that of LDCT (CTDIvol = 0.9 mGy vs. 3.7 mGy). Conclusions: Thoracic uLDCT, at a 75% dose reduction, can replace LDCT for the detection of fungal disease in IC patients with BMI < 30.0 kg/m2.

80-kV pulmonary CT angiography with 40 mL of iodinated contrast material in lean patients: comparison of vascular enhancement with iodixanol (320 mg I/mL)and iomeprol (400 mg I/mL).

OBJECTIVE: The purpose of this article is to compare the vascular enhancement obtained with a low-kilovoltage pulmonary CT angiography (CTA) protocol in lean patients, using 40 mL of a moderate-concentration isoosmolar (iodixanol, 320 mg I/mL) and a high-concentration low-osmolar (iomeprol, 400 mg I/mL) iodinated contrast medium injected at the same iodine delivery rate. SUBJECTS AND METHODS: Forty-two lean patients (31 men and 11 women; body mass index, ≤ 23 kg/m(2)) with suspected pulmonary embolism and non-small cell lung carcinoma underwent pulmonary CTA with a 64-MDCT scanner using a tube voltage of 80 kV. Twenty-three patients (54.8%) received 40 mL of iodixanol (320 mg I/mL) injected at a rate of 5 mL/s, and the remaining 19 patients (45.2%) were administered an equal volume of iomeprol (400 mg I/mL) at a flow rate of 4 mL/s. Intraarterial density was measured in the common pulmonary artery trunk, the main right and left pulmonary arteries, lobar arteries, and at the segmental level, for a total of 15 regions of interest per patient. Intravascular enhancement homogeneity from central to subsegmental level was also assessed visually using a semiquantitative score (1 = poor, 2 = good, and 3 = excellent). RESULTS: The overall vascular density of pulmonary arteries down to the segmental level was significantly higher with iodixanol (320 mg I/mL) than with iomeprol (400 mg I/mL) (p = 0.036). Enhancement homogeneity was good with both contrast agents, with no statistically significant difference between them (p = 0.8966). CONCLUSION: In 80-kV pulmonary CTA of lean patients, higher intravascular enhancement can be achieved with 40 mL of iodixanol (320 mg I/mL) than with the same volume of iomeprol (400 mg I/mL), with good vessel conspicuity down to the subsegmental level.

Acute lung injury after balloon pulmonary angioplasty results in a similar haemodynamic response and possible clinical advantage at follow-up.

Acute lung injury (ALI) is a common but poorly defined and understood complication of balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH). Little data are available on the medium term clinical outcomes of BPA complicated by ALI. We analyzed per-procedure data from 282 procedures in 109 patients and per-patient data from 85 patients. Serial right heart catheterization at baseline, after each BPA and at 3-month follow-up measured pulmonary vascular resistance (PVR), mean pulmonary artery pressure (mPAP), and cardiac output (CO). ALI (ALI+) was identified by chest radiography alone (ALIr+) or in association with hypoxia clinically (ALIcr+). Procedural predictors of ALI and patient outcomes at 3-months were compared no ALI (ALI-). ALI+ occurred in 17/282 (6.0%) procedures (ALIcr+: 2.5%, ALIr+: 3.5%). Prevailing haemodynamics (PVR: p < 0.01; mPAP: p < 0.05) at a procedural and patient level, as well as number of BPA sessions (p < 0.01), total number of vessels (p < 0.05), and occlusions (p < 0.05) treated at a patient level predicted ALI+. Those with ALI had greater percentage improvement in ΔCAMPHOR symptoms score (ALI+: -63.5 ± 35.7% (p < 0.05); ALIcr+: -84.4 ± 14.5% (p < 0.01); ALI-: -27.2 ± 74.2%) and ΔNT-proBNP (ALIcr+: -78.4 ± 11.9% (p < 0.01); ALI-: -42.9 ± 36.0%) at follow-up. There was no net significant difference in haemodynamic changes in ALI+ versus ALI- at follow-up. ALI is predicted by haemodynamic severity, number of vessels treated, number of BPA sessions, and treating occlusive disease. ALI in this cohort was associated with a clinical advantage at follow-up.

Precision-optimized single protocol pre-/post-contrast modified-look locker inversion T1 mapping using composite inversion group fitting.

BACKGROUND: Investigation of a simple, precision optimized, identical pre-/post-contrast modified look locker inversion recovery (MOLLI) protocol employing Composite inversion group (IG) fitting in a clinical cardiomyopathy population. METHODS: Cardiac magnetic resonance imaging (MRI) was performed at 3 Tesla in 36 patients (48.0 years [IQR: 35.7, 58.2 years]) with known/suspicion of hypertrophic cardiomyopathy. T1 mapping was performed pre-/post-contrast (0.15 mmol/kg Gadobutrol) using a standard 3-parameter fit (STANDARD) and an optimized (OPTIMAL) single-protocol Composite-IG fitting MOLLI approach. The OPTIMAL protocol was based on a simulation study (for 11hb acquisitions) with cost metric analysis across the range of expected T1 values (300-1400 ms) and heart rates (50-80 bpm). All maps were generated offline based on motion corrected source images. Based on region of interest analysis, the precision of both approaches was assessed using a previously validated propagation of errors technique for pre-/post-contrast T1 mapping as well as calculated ECV (based on point-of care hematocrit measurements. Furthermore, respective T1 and ECV values were calculated. Statistical methods included Wilcoxon Signed-Rank tests and Student's paired t-test. RESULTS: A total of ~9000 11hb inversion groupings were simulated with a 4(0)2(0)2(0)2(0)1 grouping providing the optimal precision across the specified T1/heart rate range. In comparison to standard pre-contrast 5(3)3 MOLLI, this OPTIMAL protocol demonstrated a significantly improved pre-contrast precision (9.1 [6.2, 9.9]ms vs. 9.4 [7.3, 10.8]ms; P < 0.001) while no significant differences were found for post-contrast T1 mapping (4.5 [2.6, 5.3]ms vs. 4.2 [2.8, 5.1]ms; P = 0.25) and EVC mapping (0.38 [0.28, 0.45]ms vs. 0.35 [0.25, 0.44]ms; P = 0.07) or reproducibility (0.16 [0.14, 0.19] vs. 0.19 [0.13, 0.23]P = 0.53). Direct comparison of resulting T1/ECV values demonstrated no significant differences between STANDARD and OPTIMAL techniques for pre-contrast T1 (1178 [1158, 1199]ms vs. 1173 [1143, 1195]ms; P = 0.46) and significant differences for post-contrast T1 (466 [446, 506]ms vs. 456 [433, 503]ms; P = 0.04) and ECV (23.1 [20.8, 25.1]% vs. 23.9 [22.3, 26.4]%; P = 0.001). CONCLUSIONS: A single optimized Composite-IG fitting protocol for pre-/post-contrast T1 mapping demonstrated improved precision over standard MOLLI techniques. It enables a simplified workflow with reduction of potential sources of error especially with respect to image data co-registration easing advanced post-processing for generation of patient specific ECV maps.

Ultrasound lung comets in systemic sclerosis: a chest sonography hallmark of pulmonary interstitial fibrosis.

OBJECTIVE: To assess the correlation between ultrasound lung comets (ULCs, a recently described echographic sign of interstitial lung fibrosis) and the current undisputed gold-standard high-resolution CT (HRCT) to detect pulmonary fibrosis in patients with SSc. METHODS: We enrolled 33 consecutive SSc patients (mean age 54 +/- 13 years, 30 females) in the Rheumatology Clinic of the University of Pisa. We assessed ULCs and chest HRCT within 1 week independently in all the patients. ULC score was obtained by summing the number of lung comets on the anterior and posterior chest. Pulmonary fibrosis was quantified by HRCT with a previously described 30-point Warrick score. RESULTS: Presence of ULCs (defined as a total number more than 10) was observed in 17 (51%) SSc patients. Mean ULC score was 37 +/- 50, higher in the diffuse than in the limited form (73 +/- 66 vs 21 +/- 35; P < 0.05). A significant positive linear correlation was found between ULCs and Warrick scores (r = 0.72; P < 0.001). CONCLUSIONS: ULCs are often found in SSc, are more frequent in the diffuse than the limited form and are reasonably well correlated with HRCT-derived assessment of lung fibrosis. They represent a simple, bedside, radiation-free hallmark of pulmonary fibrosis of potential diagnostic and prognostic value.

Quantitative analysis of epicardial fat volume: effects of scanning protocol and reproducibility of measurements in non-contrast cardiac CT vs. coronary CT angiography.

BACKGROUND: Several studies have focused on the role of epicardial fat in the pathogenesis of cardiovascular disease (CVD). The main purpose of the study was to evaluate a computerized method for the quantitative analysis of epicardial fat volume (EFV) by non-contrast cardiac CT (NCT) for coronary calcium scan and coronary CT angiography (coronary CTA). METHODS: Thirty patients (61±12.5 years, 73% male, body mass index (BMI) =25.9±6.3 kg/m2) referred to our Institution for suspected coronary artery disease (CAD) underwent NCT and coronary CTA. Epicardial boundaries were traced by 2 experienced operators (operator 1, operators 2) on 3 and 6 short-axis (SA) slices. EFV was computed with a semi-automatic method using an in-house developed software based on spherical harmonic representation of the epicardial surface. In order to analyze the inter-observer variability both the Coefficient of Repeatability (CR) and Intra Class Correlation (ICC) were computed. RESULTS: The total EFV was 103.62±50.97 and 94.96±67.91 cc in NCT and coronary CTA with non-significant difference (P=0.292). CR error was 10.22 cc for operator 1 and 11.31 cc for operator 2 in NCT and 7.99 cc for operator 1 and 7.75 cc for operator 2 in coronary CTA. To analyze the inter-observer variability CR and ICC were computed. CR was 8.17 and 8.39 cc with NCT and 7.07 and 7.21 cc with CTA for 6 and 3 SA slices respectively. ICC values >0.99 were obtained in all cases. The right ventricular EFV was 67.23±31.4 and 57.41±34.3 cc for NCT and coronary CTA respectively; the corresponding values for left ventricular EFV were 38.01±19.1 and 35.27±25.9 cc. CONCLUSIONS: Both NCT and coronary CTA can be used with low intra- and inter-observer variability for computer-assisted measurements of EFV. Cardiac CT may allow a fast and reliable computation of EFV in clinical setting.

Systematic radiation dose optimization of abdominal dual-energy CT on a second-generation dual-source CT scanner: assessment of the accuracy of iodine uptake measurement and image quality in an in vitro and in vivo investigations.

PURPOSE: To assess the accuracy of iodine quantification in a phantom study at different radiation dose levels with dual-energy dual-source CT and to evaluate image quality and radiation doses in patients undergoing a single-energy and two dual-energy abdominal CT protocols. METHODS: In a phantom study, the accuracy of iodine quantification (4.5-23.5 mgI/mL) was evaluated using the manufacturer-recommended and three dose-optimized dual-energy protocols. In a patient study, 75 abdomino-pelvic CT examinations were acquired as follows: 25 CT scans with the manufacturer-recommended dual-energy protocol (protocol A); 25 CT scans with a dose-optimized dual-energy protocol (protocol B); and 25 CT scans with a single-energy CT protocol (protocol C). CTDIvol and objective noise were measured. Five readers scored each scan according to six subjective image quality parameters (noise, contrast, artifacts, visibility of small structures, sharpness, overall diagnostic confidence). RESULTS: In the phantom study, differences between the real and measured iodine concentrations ranged from -8.8% to 17.0% for the manufacturer-recommended protocol and from -1.6% to 20.5% for three dose-optimized protocols. In the patient study, the CTDIvol of protocol A, B, and C were 12.5 ± 1.9, 7.5 ± 1.2, and 6.5 ± 1.7 mGycm, respectively (p < 0.001), and the average image noise values were 6.6 ± 1.2, 7.8 ± 1.4, and 9.6 ± 2.2 HU, respectively (p < 0.001). No significant differences in the six subjective image quality parameters were observed between the dose-optimized dual-energy and the single-energy protocol. CONCLUSION: A dose reduction of 41% is feasible for the manufacturer-recommended, abdominal dual-energy CT protocol, as it maintained the accuracy of iodine measurements and subjective image quality compared to a single-energy protocol.

Colorectal cancer: current imaging methods and future perspectives for the diagnosis, staging and therapeutic response evaluation.

In the last 10 years the mortality rate of colorectal cancer (CRC) has decreased by more than 20% due to the rising developments in diagnostic techniques and optimization of surgical, neoadjuvant and palliative therapies. Diagnostic methods currently used in the evaluation of CRC are heterogeneous and can vary within the countries and the institutions. This article aims to discuss in depth currently applied imaging modalities such as virtual computed tomography colonoscopy, endorectal ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of CRC. Special focus is put on the potential of recent diagnostic developments as diffusion weighted imaging MRI, MRI biomarkers (dynamic enhanced MRI), positron emission tomography with 2-(fluorine-18)-fluoro-2-deoxy-D-glucose (FDG-PET) combined with computed tomography (PET/CT) and new hepatobiliary MRI contrast agents. The precise role, advantage and disadvantages of these modalities are evaluated controversially in local staging, metastatic spread and treatment monitoring of CRC. Finally, the authors will touch upon the future perspectives in functional imaging evaluating the role of integrated FDG-PET/CT with perfusion CT, MRI spectroscopy of primary CRC and hepatic transit time analysis using contrast enhanced ultrasound and MRI in the detection of liver metastases. Validation of these newer imaging techniques may lead to significant improvements in the management of patients with colorectal cancer.

Lung water assessment by lung ultrasonography in intensive care: a pilot study.

OBJECTIVE: To investigate the accuracy of lung ultrasonography (LUS) in the quantification of lung water in critically ill patients by using quantitative computed tomography (CT) as the gold standard for the determination of lung weight. METHODS: Twenty consecutive patients admitted to an intensive care unit who underwent chest CT as a step in their clinical management were evaluated within 4 h by LUS. Lung weight, lung volume, and physical lung density were calculated from the CT scans using ad hoc software. Semiquantitative ultrasound assessment of lung water was performed by determining the ultrasound B-line score, defined as the total number of B-lines detectable in an anterolateral LUS examination. RESULTS: Good correlations were found between the B-line score and lung weight (r = 0.75, p < 0.05) and density (r = 0.82, p < 0.01), that only marginally increased when the lung density of the first 10 mm of subpleural lung tissue was evaluated (r = 0.83, p < 0.01). Moreover, values of subpleural lung density were not significantly different from values of the whole lung density (0.34 ± 0.11 vs. 0.37 ± 0.16 g/ml, p = ns). Very good correlations were found between the B-line score and both the weight (r = 0.85, p < 0.01) and the density (r = 0.88, p < 0.01) of the upper lobes. The weight of the lower lobes was not correlated with the B-line score (r = 0.14, p = ns). CONCLUSIONS: Lung ultrasound B-lines are correlated with lung weight and density determined by CT. LUS may provide a reliable, simple and radiation-free lung densitometry in the intensive care setting.