Accuracy of Ultrahigh-Resolution Photon-counting CT for Detecting Coronary Artery Disease in a High-Risk Population.

Background Recently introduced photon-counting CT may improve noninvasive assessment of patients with high risk for coronary artery disease (CAD). Purpose To determine the diagnostic accuracy of ultrahigh-resolution (UHR) coronary CT angiography (CCTA) in the detection of CAD compared with the reference standard of invasive coronary angiography (ICA). Materials and Methods In this prospective study, participants with severe aortic valve stenosis and clinically indicated CT for transcatheter aortic valve replacement planning were consecutively enrolled from August 2022 to February 2023. All participants were examined with a dual-source photon-counting CT scanner using a retrospective electrocardiography-gated contrast-enhanced UHR scanning protocol (tube voltage, 120 or 140 kV; collimation, 120 × 0.2 mm; 100 mL of iopromid; no spectral information). Subjects underwent ICA as part of their clinical routine. A consensus assessment of image quality (five-point Likert scale: 1 = excellent [absence of artifacts], 5 = nondiagnostic [severe artifacts]) and a blinded independent reading for the presence of CAD (stenosis ≥50%) were performed. UHR CCTA was compared with ICA using area under the receiver operating characteristic curve (AUC). Results Among 68 participants (mean age, 81 years ± 7 [SD]; 32 male, 36 female), the prevalence of CAD and prior stent placement was 35% and 22%, respectively. The overall image quality was excellent (median score, 1.5 [IQR, 1.3-2.0]). The AUC of UHR CCTA in the detection of CAD was 0.93 per participant (95% CI: 0.86, 0.99), 0.94 per vessel (95% CI: 0.91, 0.98), and 0.92 per segment (95% CI: 0.87, 0.97). Sensitivity, specificity, and accuracy, respectively, were 96%, 84%, and 88% per participant (n = 68); 89%, 91%, and 91% per vessel (n = 204); and 77%, 95%, and 95% per segment (n = 965). Conclusion UHR photon-counting CCTA provided high diagnostic accuracy in the detection of CAD in a high-risk population, including subjects with severe coronary calcification or prior stent placement. Published under a CC BY 4.0 license. Supplemental material is available for this article. See also the editorial by Williams and Newby in this issue.

Standardized measurement of abdominal muscle by computed tomography: association with cardiometabolic risk in the Framingham Heart Study.

OBJECTIVES: To provide a standard for total abdominal muscle mass (TAM) quantification on computed tomography (CT) and investigate its association with cardiovascular risk in a primary prevention setting. METHODS: We included 3016 Framingham Heart Study participants free of cardiovascular disease (CVD) who underwent abdominal CT between 2002 and 2005. On a single CT slice at the level of L3/L4, we segmented (1) TAM-Area, (2) TAM-Index (= TAM-Area/height) and, (3) TAM-Fraction (= TAM-Area/total cross-sectional CT-area). We tested the association of these muscle mass measures with prevalent and incident cardiometabolic risk factors and incident CVD events during a follow-up of 11.0 ± 2.7 years. RESULTS: In this community-based sample (49% women, mean age: 50.0 ± 10.0 years), all muscle quantity measures were significantly associated with prevalent and incident cardiometabolic risk factors and CVD events. However, only TAM-Fraction remained significantly associated with key outcomes (e.g., adj. OR 0.68 [0.55, 0.84] and HR 0.73 [0.57, 0.92] for incident hypertension and CVD events, respectively) after adjustment for age, sex, body mass index, and waist circumference. Moreover, only higher TAM-Fraction was associated with a lower risk (e.g., adj. OR: 0.56 [0.36-0.89] for incident diabetes versus TAM-Area: adj. OR 1.26 [0.79-2.01] and TAM-Index: 1.09 [0.75-1.58]). CONCLUSION: TAM-Fraction on a single CT slice at L3/L4 is a novel body composition marker of cardiometabolic risk in a primary prevention setting that has the potential to improve risk stratification beyond traditional measures of obesity. KEY POINTS: • In this analysis of the Framingham Heart Study (n = 3016), TAM-F on a single slice CT was more closely associated with prevalent and incident cardiometabolic risk factors as compared to TAM alone or TAM indexed to body surface area. • TAM-F on a single abdominal CT slice at the level of L3/L4 could serve as a standard measure of muscle mass and improve risk prediction.

Association Between Immune Checkpoint Inhibitors With Cardiovascular Events and Atherosclerotic Plaque.

BACKGROUND: Immune checkpoint inhibitors (ICIs) treat an expanding range of cancers. Consistent basic data suggest that these same checkpoints are critical negative regulators of atherosclerosis. Therefore, our objectives were to test whether ICIs were associated with accelerated atherosclerosis and a higher risk of atherosclerosis-related cardiovascular events. METHODS: The study was situated in a single academic medical center. The primary analysis evaluated whether exposure to an ICI was associated with atherosclerotic cardiovascular events in 2842 patients and 2842 controls matched by age, a history of cardiovascular events, and cancer type. In a second design, a case-crossover analysis was performed with an at-risk period defined as the 2-year period after and the control period as the 2-year period before treatment. The primary outcome was a composite of atherosclerotic cardiovascular events (myocardial infarction, coronary revascularization, and ischemic stroke). Secondary outcomes included the individual components of the primary outcome. In addition, in an imaging substudy (n=40), the rate of atherosclerotic plaque progression was compared from before to after the ICI was started. All study measures and outcomes were blindly adjudicated. RESULTS: In the matched cohort study, there was a 3-fold higher risk for cardiovascular events after starting an ICI (hazard ratio, 3.3 [95% CI, 2.0-5.5]; P<0.001). There was a similar increase in each of the individual components of the primary outcome. In the case-crossover, there was also an increase in cardiovascular events from 1.37 to 6.55 per 100 person-years at 2 years (adjusted hazard ratio, 4.8 [95% CI, 3.5-6.5]; P<0.001). In the imaging study, the rate of progression of total aortic plaque volume was >3-fold higher with ICIs (from 2.1%/y before 6.7%/y after). This association between ICI use and increased atherosclerotic plaque progression was attenuated with concomitant use of statins or corticosteroids. CONCLUSIONS: Cardiovascular events were higher after initiation of ICIs, potentially mediated by accelerated progression of atherosclerosis. Optimization of cardiovascular risk factors and increased awareness of cardiovascular risk before, during, and after treatment should be considered among patients on an ICI.

Correlates and Timing of Reproductive Aging Transitions in a Global Cohort of Midlife Women With Human Immunodeficiency Virus: Insights From the REPRIEVE Trial.

BACKGROUND: Reproductive aging may contribute to cardiometabolic comorbid conditions. We integrated data on gynecologic history with levels of an ovarian reserve marker (anti-müllerian hormone [AMH)] to interrogate reproductive aging patterns and associated factors among a subset of cisgender women with human immunodeficiency virus (WWH) enrolled in the REPRIEVE trial. METHODS: A total of 1449 WWH were classified as premenopausal (n = 482) (menses within 12 months; AMH level ≥20 pg/mL; group 1), premenopausal with reduced ovarian reserve (n = 224) (menses within 12 months; AMH <20 pg/mL; group 2), or postmenopausal (n = 743) (no menses within12 months; AMH <20 pg/mL; group 3). Proportional odds models, adjusted for chronologic age, were used to investigate associations of cardiometabolic and demographic parameters with reproductive aging milestones (AMH <20 pg/mL or >12 months of amenorrhea). Excluding WWH with surgical menopause, age at final menstrual period was summarized for postmenopausal WWH (group 3) and estimated among all WWH (groups 1-3) using an accelerated failure-time model. RESULTS: Cardiometabolic and demographic parameters associated with advanced reproductive age (controlling for chronologic age) included waist circumference (>88 vs ≤88 cm) (odds ratio [OR], 1.38; 95% confidence interval, 1.06-1.80; P = .02), hemoglobin (≥12 vs <12 g/dL) (2.32; 1.71-3.14; P < .01), and region of residence (sub-Saharan Africa [1.50; 1.07-2.11; P = .02] and Latin America and the Caribbean [1.59; 1.08-2.33; P = .02], as compared with World Health Organization Global Burden of Disease high-income regions). The median age (Q1, Q3) at the final menstrual period was 48 (45, 51) years when described among postmenopausal WWH, and either 49 (46, 52) or 50 (47, 53) years when estimated among all WWH, depending on censoring strategy. CONCLUSIONS: Among WWH in the REPRIEVE trial, more advanced reproductive age is associated with metabolic dysregulation and region of residence. Additional research on age at menopause among WWH is needed. CLINICAL TRIALS REGISTRATION: NCT0234429.

Outcomes of anatomical vs. functional testing for coronary artery disease : Lessons from the major trials.

Management of patients presenting with suspected stable coronary artery disease (CAD) are challenging because estimation of pretest probability for obstructive CAD remains difficult. In addition, identification of those who benefit from coronary revascularization remains ineffective regardless of the wide array of noninvasive testing alternatives available. Functional testing, which has long been considered to be the test of choice to risk stratify these patients, shows modest agreement with CAD severity detected by invasive coronary angiography and has been reported to be ineffective in settings of low prevalence of obstructive CAD. A growing body of evidence demonstrates the excellent diagnostic accuracy as well as prognostic value of coronary computed tomography (CT) angiography especially in conjunction with noninvasive fractional flow reserve (FFR) testing, challenging the primary role of functional testing especially in patients without prior or known CAD. Landmark trials, including the Prospective Multicenter Imaging Study for Evaluation of chest pain (PROMISE) and Scottish Computed Tomography of the Heart (SCOT-HEART), have contributed to a better understanding of how coronary CT angiography may play a role in more efficient management and even improved health outcomes. The emerging role of coronary CT has been acknowledged by the 2019 Guidelines of the European Society of Cardiology recommending the use of CT as a first-line tool for the evaluation of patients with stable chest pain with a class I, level of evidence B recommendation. The purpose of this article is to provide an overview on existing evidence, clinical implication, limitations of available data, and remaining questions to be answered by future research.

Erratum to: Outcomes of anatomical vs. functional testing for coronary artery disease : Lessons from the major trials.

In the above-mentioned article, in the section "Other randomized controlled studies, meta-analyses, and registry data" two subheadings were swapped by mistake. The sections concerned must instead be headed as ….

[Update on coronary CT-more than just anatomical imaging? : Current guidelines and functional CT techniques for the quantification of stenoses]. / Update Kardio-CT ­ mehr als nur anatomische Bildgebung? : Aktuelle Leitlinien und funktionelle CT-Techniken zur Stenosequantifizierung.

BACKGROUND: Coronary CT angiography (cCTA) has a high negative predictive value for ruling out significant coronary stenoses. However, it is limited in determining hemodynamic significance of a stenosis and hence to prove the indication for therapy. OBJECTIVES: When and how is cCTA used according to current guidelines? Which functional CT techniques are available to test for hemodynamic significance of coronary stenoses? MATERIALS AND METHODS: The value of cCTA is explained on the basis of current guidelines by the European Society of Cardiology (ESC) for the diagnosis of chronic coronary syndromes. Functional CT techniques which test for hemodynamic significance of coronary stenoses are myocardial CT-perfusion (CT­P) and CT-based fractional flow reserve (CT-FFR). RESULTS: The new ESC guidelines classify cCTA as a class 1 recommendation for diagnosing coronary artery disease in symptomatic patients with low clinical likelihood. If clinical likelihood is high or an at least moderate stenosis is detected with cCTA, noninvasive functional (stress) imaging is preferred. There is a large body of evidence for CT­P and CT-FFR as functional tests. CONCLUSION: In the current guidelines, cCTA is highly recommended for the diagnosis of coronary artery disease. The functional CT techniques CT­P and CT-FFR have shown high diagnostic accuracy for myocardial ischemia of coronary stenoses in many clinical studies. However, these methods are not part of current guidelines yet and clinical adoption is still low.

Background parenchymal enhancement in pregnancy-associated breast cancer: a hindrance to diagnosis?

PURPOSE: The purpose of this study is to investigate the detectability of pregnancy-associated breast cancer (PABC) in lactating glandular tissue on magnetic resonance imaging (MRI) by using pre- and post-contrast acquisitions and their derived postprocessed images and compare these results to ultrasound (US) and mammography (MG). MATERIALS AND METHODS: We reviewed the electronic database for women with PABC and existing breast MRI. MR images (T2-weighted short inversion-recovery sequence [STIR], dynamic contrast-enhanced T1-weighted gradient echo sequence and postprocessed subtraction images [early post-contrast minus pre-contrast]) were retrospectively evaluated (image quality, parenchymal/tumour enhancement kintetics, tumour size and additional lesions). Supplemental subtraction images (latest post-contrast minus early post-contrast) to reduce plateau enhancement were additionally calculated and tumour conspicuity and size were measured. Findings were compared to US and MG reports. RESULTS: Nineteen patients (range 27-42 years) were included. Background parenchymal enhancement (BPE) was minimal (n=1), mild (n=3), moderate (n=7) and marked (n=8) with kinetics measured plateau (n=8), continuous (n=10) and not quantifiable (n=1). Tumour kinetics presented wash-out (n=17) and plateau (n=2). Eighteen of nineteen tumours were identified on the supplemental subtraction images. All tumours were visible on US; 12/19 were visible on MG (63.2%). MRI detected additional malignant lesions in two patients. CONCLUSION: Despite high BPE of the lactating breast, MRI securely detects carcinomas and identifies satellite lesions. By using supplemental subtraction images, background enhancement can be eliminated to facilitate diagnosis. US remains a reliable diagnostic tool, but additional MRI is recommended to rule out satellite/contralateral lesions. MG interpretations can be difficult due to high parenchymal density. KEY POINTS: • Despite high background enhancement, MRI of the breast confidently detects carcinomas and identifies further lesions in the lactating breast. • By using supplemental subtraction images, background enhancement in the lactating breast can be eliminated to facilitate diagnosis. • US remains a reliable diagnostic tool. Mammography can be limited due to extremely dense breast tissue related to lactation.

Self-gated 4D-MRI of the liver: Initial clinical results of continuous multiphase imaging of hepatic enhancement.

PURPOSE: To evaluate the feasibility of a self-gated free-breathing volume-interpolated breath-hold examination (VIBE) sequence using compressed sensing (CS) for contrast-enhanced multiphase liver MRI. MATERIALS AND METHODS: We identified 23 patients who underwent multiphase gadobutrol-enhanced liver magnetic resonance imaging (MRI) using 1) a prototype free-breathing VIBE sequence with respiratory self-gating and CS (VIBECS ), and 2) a standard breath-hold VIBE (VIBESTD ) on the same 1.5T scanner at two timepoints. VIBECS was continuously acquired for 128 seconds and a time-series of 16 timepoints was jointly reconstructed from the dataset. The unenhanced, arterial, portal-venous, and venous timepoints with the best image quality were selected and compared to the corresponding VIBESTD series serving as reference. Image quality was assessed qualitatively (image quality, sharpness, lesion conspicuity, vessel contrast, noise, motion/other artifacts; two readers independently; 5-point Likert scale; 5 = excellent) and quantitatively (vessel contrast [VC], coefficient-of-variation [CV]) Statistics were performed using Wilcoxon-sign-rank (ordinal) and paired t-test (continuous variables). RESULTS: Image quality and lesion conspicuity revealed no significant differences between the sequences (P ≥ 0.3). VIBESTD showed a tendency to higher motion artifacts (P ≥ 0.07). Image sharpness significantly increased in VIBECS as compared to VIBESTD (P ≤ 0.03). Arterial phase vessel contrast appeared significantly lower in VIBECS than in VIBESTD (P = 0.04). VIBECS showed reconstruction artifacts not present in VIBESTD (P = 0.001). Image noise was significantly lower in VIBECS than in VIBESTD (P ≤ 0.004). Arterial phase VC was significantly lower in VIBECS than in VIBESTD (P = 0.01). CV revealed no differences between sequences (P = 0.7). CONCLUSION: VIBECS is feasible for continuous free-breathing contrast-enhanced multiphase liver MRI, providing similar image quality and lesion conspicuity as VIBESTD . LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2018;47:459-467.

Simultaneous multislice diffusion-weighted imaging in whole-body positron emission tomography/magnetic resonance imaging for multiparametric examination in oncological patients.

OBJECTIVES: The aim of this study was to compare the diagnostic performance of simultaneous multislice diffusion-weighted imaging (DWI-SMS) with that of standard DWI (DWI-STD) in whole-body 3-T PET/MRI examination protocols in oncological patients. METHODS: In a phantom study, we evaluated the apparent diffusion coefficients (ADC) from the two techniques. In ten volunteers, we assessed ADC values in different organs. In 20 oncological patients, we evaluated subjective image quality (Likert scale, 5 indicating excellent) and artefacts in different body regions. We also rated the conspicuity and acquired the ADC values of PET-positive tumorous lesions. RESULTS: The scan time for the whole-body DWI-SMS examinations was 40% shorter than the scan time for the DWI-STD examinations (84 s vs. 140 s per table position). The phantom and volunteer studies showed lower ADC values from DWI-SMS in the liver and muscle (psoas muscle 1.4 vs. 1.3). In patients, DWI-SMS provided poorer subjective image quality in the thoracoabdominal region (3.0 vs. 3.8, p = 0.02) and overall more artefacts (138 vs. 105). No significant differences regarding conspicuity and ADC values of lesions were found. CONCLUSIONS: DWI-SMS seems to provide reliable conspicuity and ADC values of tumorous lesions similar to those provided by DWI-STD. Therefore, although providing poorer image quality in certain regions, DWI-SMS can clearly reduce PET/MRI scan times in oncological patients. KEY POINTS: • DWI-SMS can reduce PET/MRI scan times in oncological patients. • DWI-SMS provides reliable ADC values and good lesion conspicuity similar to those provided by DWI-STD. • DWI-SMS may provide poorer image quality in regions with low signal.

Scan time reduction in diffusion-weighted imaging of the pancreas using a simultaneous multislice technique with different acceleration factors: How fast can we go?

OBJECTIVES: To investigate the feasibility of simultaneous multislice-accelerated diffusion-weighted imaging (sms-DWI) of the pancreas with different acceleration factors and its influence on image quality, acquisition time and apparent diffusion coefficients (ADCs) in comparison to conventional sequences. METHODS: DWI of the pancreas was performed at 1.5T in ten healthy volunteers and 20 patients with sms-accelerated echo-planar DWI using two different sms-acceleration factors of 2 and 3 (sms2/3-DWI). These DWI sequences were compared to conventional DWI (c-DWI) in terms of image quality parameters (5-point Likert scale) and ADC measurements. RESULTS: c-DWI and sms2-DWI offered equivalently high overall image quality (4 [1; 5]) with scan time reduction to one-third (c-DWI: 173 s, sms2-DWI: 56 s). Sms3-DWI showed significantly poorer overall image quality (3 [1; 5]; p < 0.0001). ADC values were significantly lower in sms3-DWI compared to c-DWI in the pancreatic body and tail (body: c-DWI 1.4 x 10-3 mm2/s, sms3-DWI 1.0 x 10-3 mm2/s, p = 0.028; tail: c-DWI 1.3 x 10-3 mm2/s and sms3-DWI 1.0 x 10-3 mm2/s, p = 0.014). CONCLUSIONS: Accelerated multislice DWI of the pancreas offers high image quality with a substantial reduction of acquisition time. Lower ADC values in multislice DWI should be considered in diagnostic reading. KEY POINTS: • Simultaneous multislice-accelerated diffusion-weighted imaging (sms-DWI) promises scan time minimisation. • Sms-DWI of the pancreas offers diagnostic image quality in volunteers and patients. • Sms-DWI with an acceleration factor of 2 offers high image quality. • Higher acceleration factors in sms-DWI do not provide sufficient diagnostic image quality. • ADC values may be lower in sms-DWI.

Feasibility of accelerated simultaneous multislice diffusion-weighted MRI of the prostate.

PURPOSE: To assess the feasibility of simultaneous multislice (SMS) single-shot echo-planar-imaging (EPI) for accelerated diffusion-weighted imaging (DWI) of the prostate. MATERIALS AND METHODS: For phantom measurements a dedicated DWI phantom with different sucrose concentrations was used. In addition, 10 volunteers and 16 patients with suspected prostate cancer were examined for in vivo measurements. All examinations were performed with a 3T magnetic resonance imaging (MRI) system. A prototype simultaneous multislice EPI sequence (DW-EPISMS ; acquisition time 3:14 min) was acquired and compared to a single-shot EPI sequence (DW-EPISS ; acquisition time 6:12 min) serving as a standard of reference. Different image quality parameters of EPISMS were assessed qualitatively (overall image quality, anatomic differentiability, lesion conspicuity, image noise, distortion; two independent readers; 5-point Likert-scale [5 = excellent]) and quantitatively (ADC-values by calculating interclass correlation [ICC] and Bland-Altman limits of agreement [LoA] as measures for reproducibility) and compared to DW-EPISS . RESULTS: DW-EPISMS allowed for a substantially reduced acquisition time as compared to DW-EPISS (˜50%). Bland-Altman plots revealed robust measurement repeatability for DW-EPISMS in the phantom study. Overall image quality did not significantly differ between DW-EPISMS and DW-EPISS (b1500 images P = 0.5; ADC maps P = 0.7). Only in b1500 DW images was subjective image noise rated significantly higher in DW-EPISS than in DW-EPISMS (P = 0.006). Quantitative analysis of ADC-values revealed not significant differences between DW-EPISMS and DW-EPISS (P = 0.7) and high measures for reproducibility ICC ≥0.96. CONCLUSION: Simultaneous multislice DWI is feasible for accelerated prostate MRI allowing for a substantially reduced examination time with similar image quality and ADC-values as compared to a standard of reference DWI sequence. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1507-1515.

Feasibility of self-gated isotropic radial late-phase MR imaging of the liver.

OBJECTIVE: To evaluate feasibility of a 3D-isotropic self-gated radial volumetric interpolated breath-hold examination (VIBE) for late-phase MRI of the liver. MATERIAL AND METHODS: 70 patients were included and underwent liver MRI at 1.5 T. Depending on the diagnosis, either Gd-EOB-DTPA (35 patients) or gadobutrol (35 patients) were administered. During late (gadobutrol) or hepatocyte-specific phase (Gd-EOB-DTPA), a radial prototype sequence was acquired and reconstructed using (1) self-gating with 40 % acceptance (rVIBE40); (2) with 100 % acceptance of the data (rVIBE100) and compared to Cartesian VIBE (cVIBE). Images were assessed qualitatively (image quality, lesion conspicuity, artefacts; 5-point Likert-scale: 5 = excellent; two independent readers) and quantitatively (coefficient-of-variation (CV); contrast-ratio) in axial and coronal reformations. RESULTS: In eight cases only rVIBE provided diagnostic image quality. Image quality of rVIBE40 was rated significantly superior (p < 0.05) in Gd-EOB-DTPA-enhanced and coronal reformatted examinations as compared to cVIBE. Lesion conspicuity was significantly improved (p < 0.05) in coronal reformatted Gd-EOB-DTPA-enhanced rVIBE40 in comparison to cVIBE. CV was higher in rVIBE40 as compared to rVIBE100/cVIBE (p < 0.01). Gadobutrol-enhanced rVIBE40 and cVIBE showed higher contrast-ratios than rVIBE100 (p < 0.001), whereas no differences were found in Gd-EOB-DTPA-enhanced examinations. CONCLUSION: Self-gated 3D-isotropic rVIBE provides significantly superior image quality compared to cVIBE, especially in multiplanar reformatted and Gd-EOB-DTPA-enhanced examinations. KEY POINTS: • Radial VIBE acquisition reduces motion artefacts. • Gd-EOB-DTPA-enhanced scans provide improved image quality. • Non-diagnostic liver MRI examinations may be reduced by radial k-spaces sampling.

Simultaneous multislice diffusion-weighted MRI of the liver: Analysis of different breathing schemes in comparison to standard sequences.

PURPOSE: To systematically evaluate image characteristics of simultaneous-multislice (SMS)-accelerated diffusion-weighted imaging (DWI) of the liver using different breathing schemes in comparison to standard sequences. MATERIALS AND METHODS: DWI of the liver was performed in 10 healthy volunteers and 12 patients at 1.5T using an SMS-accelerated echo planar imaging sequence performed with respiratory-triggering and free breathing (SMS-RT, SMS-FB). Standard DWI sequences served as reference (STD-RT, STD-FB). Reduction of scan time by SMS-acceleration was measured. Image characteristics of SMS-DWI and STD-DWI with both breathing schemes were analyzed quantitatively (apparent diffusion coefficient [ADC], signal-to-noise ratio [SNR]) and qualitatively (5-point Likert scale, 5 = excellent). Qualitative and quantitative parameters were compared using Friedman test and Dunn-Bonferroni post-hoc method with P-values < 0.05 considered statistically significant. RESULTS: SMS-DWI provided diagnostic image quality in volunteers and patients both with RT and FB with a reduction of scan time of 70% (0:56 vs. 3:20 min in FB). Overall image quality did not significantly differ between FB and RT acquisition in both STD and SMS sequences (median STD-RT 5.0, STD-FB 4.5, SMS-RT: 4.75; SMS-FB: 4.5; P = 0.294). SNR in the right hepatic lobe was comparable between the four tested sequences. ADC values were significantly lower in SMS-DWI compared to STD-DWI irrespective of the breathing scheme (1.2 ± 0.2 × 10(-3) mm(2) /s vs. 1.0 ± 0.2 × 10(-3) mm(2) /s; P < 0.001). CONCLUSION: SMS-acceleration provides considerable scan time reduction for hepatic DWI with equivalent image quality compared to the STD technique both using RT and FB. Discrepancies in ADC between STD-DWI and SMS-DWI need to be considered when transferring the SMS technique to clinical routine reading. J. MAGN. RESON. IMAGING 2016;44:865-879.

Scan time minimization in hepatic diffusion-weighted imaging: evaluation of the simultaneous multislice acceleration technique with different acceleration factors and gradient preparation schemes.

OBJECTIVE: To evaluate simultaneous multislice (sms) accelerated diffusion-weighted imaging (DWI) of the liver in comparison to conventional sequences. MATERIALS AND METHODS: Ten volunteers underwent DWI of the liver at 1.5 T. Four different sms-accelerated sequences with monopolar and bipolar gradient preparation (MP, BP) and acceleration factors 2 and 3 (sms2-DWI, sms3-DWI) were compared to conventional DWI (c-DWI). Image quality criteria rated on a 5-point Likert scale (5 = excellent), image quality sum scores (maximum 120), and ADC were compared using Friedman test and Dunn-Bonferroni post hoc test. Bland-Altman plots were calculated for ADC comparison. p values <0.05 were considered significant. RESULTS: Sms2-DWI offered scan time minimization of 67 % without significant difference in image quality (sum score: sms2-DWI MP/BP: 97 ± 8/92 ± 9; c-DWI MP/BP: 99 ± 8/97 ± 8). Sms3-DWI offered slight additional scan time minimization with significantly inferior image quality (sum score: sms3-DWI MP/BP: 75 ± 14/69 ± 14; p < 0.001). MP preparation provided slightly higher image quality in sms-DWI without statistical significance. ADC in sms-DWI were significantly lower (sms2-DWI MP 1.01 × 10(-3) mm(2)/s; c-DWI MP 1.20 × 10(-3) mm(2)/s; p < 0.001). CONCLUSION: Sms2-DWI provides considerable scan time minimization without significant shortcomings in image quality. Sms3-DWI provides significantly inferior image quality without further scan time minimization. Potentially lower ADC in sms-DWI should be considered in clinical routine.

Ultrashort VIBE-Dixon versus Cine and late gadolinium enhancement MRI sequences for cardiac thrombus detection.

PURPOSE: To determine the diagnostic accuracy of volumetric interpolated breath-hold examination sequences with fat suppression in Dixon technique (VIBE-Dixon) for cardiac thrombus detection. METHOD: From our clinical database, we retrospectively identified consecutive patients between 2014 and 2022 who had definite diagnosis or exclusion of cardiac thrombus confirmed by an independent adjudication committee, serving as the reference standard. All patients received 2D-Cine plus 2D-Late-Gadolinium-Enhancement (Cine + LGE) and VIBE-Dixon sequences. Two blinded readers assessed all images for the presence of cardiac thrombus. The diagnostic accuracy of Cine + LGE and VIBE-Dixon was determined and compared. RESULTS: Among 141 MRI studies (116 male, mean age: 61 years) mean image examination time was 28.8 ± 3.1 s for VIBE-Dixon and 23.3 ± 2.5 min for Cine + LGE. Cardiac thrombus was present in 49 patients (prevalence: 35 %). For both readers sensitivity for thrombus detection was significantly higher in VIBE-Dixon compared with Cine + LGE (Reader 1: 96 % vs.73 %, Reader 2: 96 % vs. 78 %, p < 0.01 for both readers), whereas specificity did not differ significantly (Reader 1: 96 % vs. 98 %, Reader 2: 92 % vs. 93 %, p > 0.1). Overall diagnostic accuracy of VIBE-Dixon was higher than for Cine + LGE (95 % vs. 89 %, p = 0.02) and was non-inferior to the reference standard (Delta ≤ 5 % with probability > 95 %). CONCLUSIONS: Biplanar VIBE-Dixon sequences, acquired within a few seconds, provided a very high diagnostic accuracy for cardiac thrombus detection. They could be used as stand-alone sequences to rapidly screen for cardiac thrombus in patients not amenable to lengthy acquisition times.

Photon-counting computed tomography - clinical application in oncological, cardiovascular, and pediatric radiology. / Photon-Counting Computertomographie ­ klinische Anwendungen in der onkologischen, kardiovaskulären und pädiatrischen Radiologie.

BACKGROUND: Photon-counting detector computed tomography (PCD-CT) is a promising new technology with the potential to fundamentally change workflows in the daily routine and provide new quantitative imaging information to improve clinical decision-making and patient management. METHOD: The contents of this review are based on an unrestricted literature search of PubMed and Google Scholar using the search terms "photon-counting CT", "photon-counting detector", "spectral CT", "computed tomography" as well as on the authors' own experience. RESULTS: The fundamental difference with respect to the currently established energy-integrating CT detectors is that PCD-CT allows for the counting of every single photon at the detector level. Based on the identified literature, PCD-CT phantom measurements and initial clinical studies have demonstrated that the new technology allows for improved spatial resolution, reduced image noise, and new possibilities for advanced quantitative image postprocessing. CONCLUSION: For clinical practice, the potential benefits include fewer beam hardening artifacts, a radiation dose reduction, and the use of new or combinations of contrast agents. In particular, critical patient groups such as oncological, cardiovascular, lung, and head & neck as well as pediatric patient collectives benefit from the clinical advantages. KEY POINTS: · Photon-counting computed tomography (PCD-CT) is being used for the first time in routine clinical practice, enabling a significant dose reduction in critical patient populations such as oncology, cardiology, and pediatrics.. · Compared to conventional CT, PCD-CT enables a reduction in electronic image noise.. · Due to the spectral data sets, PCD-CT enables fully comprehensive post-processing applications.. CITATION FORMAT: · Hagen F, Soschynski M, Weis M et al. Photon-counting computed tomography - clinical application in oncological, cardiovascular, and pediatric radiology. Fortschr Röntgenstr 2024; 196: 25 - 34.

Cytomegalovirus IgG is Associated With Physical Function But Not Muscle Density in People With HIV.

BACKGROUND: Cytomegalovirus (CMV) seropositivity is associated with poor outcomes, including physical function impairment, in people without HIV. We examined associations between CMV IgG titer and physical function in virologically suppressed people with HIV (PWH). METHODS: REPRIEVE is a double-blind randomized trial evaluating pitavastatin for primary prevention of atherosclerotic cardiovascular disease in PWH. This analysis focused on participants enrolled in a substudy with additional biomarker testing, imaging [coronary CT angiography], and physical function measures at entry. CMV IgG was measured using quantitative enzyme immunoassay, physical function by Short Physical Performance Battery, and muscle density and area by CT. Associations between CMV IgG (risk factor) and outcomes were evaluated using the partial Spearman correlation and linear and log-binomial regression. RESULTS: Among 717 participants, 82% male, the median CMV IgG was 2716 (Q1, Q3: 807, 6672) IU/mL, all above the limit of quantification. Among 631 participants with imaging, there was no association between CMV IgG and CT-based muscle density or area, controlling for age (r = -0.03 and r = -0.01, respectively; P ≥ 0.38). Among 161 participants with physical function data, higher CMV IgG was associated with poorer overall modified Short Physical Performance Battery score ( P = 0.02), adjusted for age, nadir CD4, and high-sensitivity C-reactive protein. CONCLUSIONS: Higher CMV IgG titer was associated with poorer physical function, not explained by previous immune compromise, inflammation, or muscle density or area. Further mechanistic studies are needed to understand this association and whether CMV-specific therapy can affect physical function in PWH.

Coronary Plaque in People With HIV vs Non-HIV Asymptomatic Community and Symptomatic Higher-Risk Populations.

Background: People with HIV (PWH) have a high burden of coronary plaques; however, the comparison to people without known HIV (PwoH) needs clarification. Objectives: The purpose of this study was to determine coronary plaque burden/phenotype in PWH vs PwoH. Methods: Nonstatin using participants from 3 contemporary populations without known coronary plaques with coronary CT were compared: the REPRIEVE (Randomized Trial to Prevent Vascular Events in HIV) studying PWH without cardiovascular symptoms at low-to-moderate risk (n = 755); the SCAPIS (Swedish Cardiopulmonary Bioimage Study) of asymptomatic community PwoH at low-to-intermediate cardiovascular risk (n = 23,558); and the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) of stable chest pain PwoH (n = 2,291). The coronary plaque prevalence on coronary CT was compared, and comparisons were stratified by 10-year atherosclerotic cardiovascular disease (ASCVD) risk, age, and coronary artery calcium (CAC) presence. Results: Compared to SCAPIS and PROMISE PwoH, REPRIEVE PWH were younger (50.8 ± 5.8 vs 57.3 ± 4.3 and 60.0 ± 8.0 years; P < 0.001) and had lower ASCVD risk (5.0% ± 3.2% vs 6.0% ± 5.3% and 13.5% ± 11.0%; P < 0.001). More PWH had plaque compared to the asymptomatic cohort (48.5% vs 40.3%; P < 0.001). When stratified by ASCVD risk, PWH had more plaque compared to SCAPIS and a similar prevalence of plaque compared to PROMISE. CAC = 0 was more prevalent in PWH (REPRIEVE 65.2%; SCAPIS 61.6%; PROMISE 49.6%); among CAC = 0, plaque was more prevalent in PWH compared to the PwoH cohorts (REPRIEVE 20.8%; SCAPIS 5.4%; PROMISE 12.3%, P < 0.001). Conclusions: Asymptomatic PWH in REPRIEVE had more plaque than asymptomatic PwoH in SCAPIS but had similar prevalence to a higher-risk stable chest pain cohort in PROMISE. In PWH, CAC = 0 does not reliably exclude plaque.

Effects of Pitavastatin on Coronary Artery Disease and Inflammatory Biomarkers in HIV: Mechanistic Substudy of the REPRIEVE Randomized Clinical Trial.

Importance: Cardiovascular disease (CVD) is increased in people with HIV (PWH) and is characterized by premature noncalcified coronary plaque. In the Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE), pitavastatin reduced major adverse cardiovascular events (MACE) by 35% over a median of 5.1 years. Objective: To investigate the effects of pitavastatin on noncalcified coronary artery plaque by coronary computed tomography angiography (CTA) and on inflammatory biomarkers as potential mechanisms for MACE prevention. Design, Setting, and Participants: This double-blind, placebo-controlled randomized clinical trial enrolled participants from April 2015 to February 2018 at 31 US clinical research sites. PWH without known CVD who were taking antiretroviral therapy and had low to moderate 10-year CVD risk were included. Data were analyzed from April to November 2023. Intervention: Oral pitavastatin calcium, 4 mg per day. Main Outcomes and Measures: Coronary CTA and inflammatory biomarkers at baseline and 24 months. The primary outcomes were change in noncalcified coronary plaque volume and progression of noncalcified plaque. Results: Of 804 enrolled persons, 774 had at least 1 evaluable CTA. Plaque changes were assessed in 611 who completed both CT scans. Of 611 analyzed participants, 513 (84.0%) were male, the mean (SD) age was 51 (6) years, and the median (IQR) 10-year CVD risk was 4.5% (2.6-7.0). A total of 302 were included in the pitavastatin arm and 309 in the placebo arm. The mean noncalcified plaque volume decreased with pitavastatin compared with placebo (mean [SD] change, -1.7 [25.2] mm3 vs 2.6 [27.1] mm3; baseline adjusted difference, -4.3 mm3; 95% CI, -8.6 to -0.1; P = .04; 7% [95% CI, 1-12] greater reduction relative to placebo). A larger effect size was seen among the subgroup with plaque at baseline (-8.8 mm3 [95% CI, -17.9 to 0.4]). Progression of noncalcified plaque was 33% less likely with pitavastatin compared with placebo (relative risk, 0.67; 95% CI, 0.52-0.88; P = .003). Compared with placebo, the mean low-density lipoprotein cholesterol decreased with pitavastatin (mean change: pitavastatin, -28.5 mg/dL; 95% CI, -31.9 to -25.1; placebo, -0.8; 95% CI, -3.8 to 2.2). The pitavastatin arm had a reduction in both oxidized low-density lipoprotein (-29% [95% CI, -32 to -26] vs -13% [95% CI, -17 to -9]; P < .001) and lipoprotein-associated phospholipase A2 (-7% [95% CI, -11 to -4] vs 14% [95% CI, 10-18]; P < .001) compared with placebo at 24 months. Conclusions and Relevance: In PWH at low to moderate CVD risk, 24 months of pitavastatin reduced noncalcified plaque volume and progression as well as markers of lipid oxidation and arterial inflammation. These changes may contribute to the observed MACE reduction in REPRIEVE. Trial Registration: ClinicalTrials.gov Identifier: NCT02344290.