Comprehensive morphologic and functional imaging of heart transplant patients: first experience with dynamic perfusion CT.

OBJECTIVES: We aimed to assess the diagnostic performance of a combined protocol with coronary computed tomography angiography (CCTA) and stress CT perfusion imaging (CTP) in heart transplant patients for comprehensive morphological and functional imaging. METHODS: In this prospective study, 13 patients undergoing routine follow-up 8±6 years after heart transplantation underwent CCTA and dynamic adenosine stress CTP using a third-generation dual-source CT scanner, cardiac magnetic resonance (MR) adenosine stress perfusion imaging at 1.5 T, and catheter coronary angiography. In CCTA stenoses >50% luminal diameter narrowing were noted. Myocardial perfusion deficits were documented in CTP and MR. Quantitative myocardial blood flow (MBF) was calculated with CTP. Left ventricular ejection fraction was determined on cardiac MR cine images. Radiation doses of CT were determined. RESULTS: One of the 13 patients had to be excluded because of severe motion artifacts. CCTA identified three patients with stenosis >50%, which were confirmed with catheter coronary angiography. CTP showed four patients with stress-induced myocardial hypoperfusion, which were confirmed by MR stress perfusion imaging. Quantitative analysis of global MBF showed lower mean values as compared to known reference values (MBF under stress 125.5 ± 34.5 ml/100 ml/min). Average left ventricular ejection fraction was preserved (56 ± 5%). CONCLUSIONS: In heart transplant patients, a comprehensive CT protocol for the assessment of morphology and function including CCTA and CTP showed good concordance to results from MR perfusion imaging and catheter coronary angiography. KEY POINTS: • Stress CT perfusion imaging enables the detection of myocardial ischemia • CT myocardial perfusion imaging can be combined with coronary computed tomography angiography • Combining perfusion and coronary CT imaging is accurate in heart transplant patients • CT myocardial perfusion imaging can be performed at a reasonable radiation dose.

[Abdominal injuries in polytraumatized adults : Systematic review]. / Abdominalverletzungen des polytraumatisierten Erwachsenen : Systematischer Überblick.

Abdominal injuries are potentially life-threatening and occur in 20-25% of all polytraumatized patients. Blunt trauma is the main mechanism. The liver and spleen are most commonly injured and much less often the intestines. The clinical evaluation proves equivocal in many cases; therefore, the gold standard is computed tomography (CT), which has been increasingly used even in hemodynamically weakly stable or sometimes even unstable patients because it promptly provides precise diagnostic findings, which present the basis for successful therapy. Hemodynamically unstable patients always need an exploratory laparotomy (EL). An EL should also be carried out with a positive focused assessment with sonography for trauma (FAST) or CT for severe parenchymal lesions, hollow organ lesions, intraperitoneal bladder lesions, peritonitis and organ evisceration, impalement injuries and lesions of the abdominal fascia. Hemodynamically stable patients without signs of peritonitis and a lack of such findings can often be treated conservatively irrespective of the extent of an injury. Angiography (and if needed embolization) can additionally be diagnostically and therapeutically utilized.

Automatic radiation dose monitoring for CT of trauma patients with different protocols: feasibility and accuracy.

AIM: To demonstrate the feasibility and accuracy of automatic radiation dose monitoring software for computed tomography (CT) of trauma patients in a clinical setting over time, and to evaluate the potential of radiation dose reduction using iterative reconstruction (IR). MATERIALS AND METHODS: In a time period of 18 months, data from 378 consecutive thoraco-abdominal CT examinations of trauma patients were extracted using automatic radiation dose monitoring software, and patients were split into three cohorts: cohort 1, 64-section CT with filtered back projection, 200 mAs tube current-time product; cohort 2, 128-section CT with IR and identical imaging protocol; cohort 3, 128-section CT with IR, 150 mAs tube current-time product. Radiation dose parameters from the software were compared with the individual patient protocols. Image noise was measured and image quality was semi-quantitatively determined. RESULTS: Automatic extraction of radiation dose metrics was feasible and accurate in all (100%) patients. All CT examinations were of diagnostic quality. There were no differences between cohorts 1 and 2 regarding volume CT dose index (CTDIvol; p=0.62), dose-length product (DLP), and effective dose (ED, both p=0.95), while noise was significantly lower (chest and abdomen, both -38%, p<0.017). Compared to cohort 1, CTDIvol, DLP, and ED in cohort 3 were significantly lower (all -25%, p<0.017), similar to the noise in the chest (-32%) and abdomen (-27%, both p<0.017). Compared to cohort 2, CTDIvol (-28%), DLP, and ED (both -26%) in cohort 3 was significantly lower (all, p<0.017), while noise in the chest (+9%) and abdomen (+18%) was significantly higher (all, p<0.017). CONCLUSION: Automatic radiation dose monitoring software is feasible and accurate, and can be implemented in a clinical setting for evaluating the effects of lowering radiation doses of CT protocols over time.

Advanced virtual monoenergetic images: improving the contrast of dual-energy CT pulmonary angiography.

AIM: To investigate the value of advanced virtual monoenergetic image reconstruction (mono-plus) from dual-energy computed tomography (CT) for improving the contrast of CT pulmonary angiography (CTPA). MATERIALS AND METHODS: Forty consecutive patients (25 women, mean 62.5 years, range 28-87 years) underwent 192-section dual-source CTPA with dual-energy CT (90/150 SnkVp) after the administration of 60 ml contrast media (300 mg iodine/ml). Conventional virtual monochromatic images at 60 keV and 17 mono-plus image datasets from 40-190 keV (in 10 keV steps) were reconstructed. Subjective image quality (artefacts, subjective noise) was rated. Attenuation was measured in the pulmonary trunk and in the right lower lobe pulmonary artery; noise was measured in the periscapular musculature. The signal-to-noise (SNR) and contrast-to-noise ratios (CNR) were calculated for each patient and dataset. Comparisons between monochromatic images and mono-plus images were performed by repeated measures analysis of variance (ANOVA) with post-hoc Bonferroni correction. RESULTS: Interreader agreement was good to excellent for subjective image quality (ICC: 0.616-0.889). As compared to conventional 60 keV images, artefacts occurred less (p=0.001) and subjective noise was rated lower (p<0.001) in mono-plus 40 keV images. Noise was lower (p<0.001), and the SNR and CNR in the pulmonary trunk and right lower lobe pulmonary artery were higher (both, p<0.001) in mono-plus 40 keV images compared to conventional monoenergetic 60 keV images. Transient interruption of contrast (TIC) was found in 14/40 (35%) of patients, with subjective contrast being similar 8/40 (20%) or higher 32/40 (80%) in mono-plus 40 keV as compared to conventional monoenergetic 60 keV images. CONCLUSIONS: Compared to conventional virtual monoenergetic imaging, mono-plus images at 40 keV improve the contrast of dual-energy CTPA.

Model-based iterative reconstruction for improvement of low-contrast detectability in liver CT at reduced radiation dose: ex-vivo experience.

AIM: To compare low-contrast detectability, and qualitative and quantitative image parameters on standard and reduced radiation dose abdominal CT reconstructed with filtered back projection (FBP) and model-based iterative reconstruction (MBIR). MATERIALS AND METHODS: A custom built liver phantom containing 43 lesions was imaged at 120 kVp and four radiation dose levels (100% = 188 mAs, 50%, 25%, and 10%). Image noise and contrast-to-noise ratios (CNR) were assessed. Lesion detection and qualitative image analysis (five-point Likert scale with 1 = worst, 5 = best for confidence) was performed by three independent radiologists. RESULTS: CNR on MBIR images was significantly higher (mean 246%, range 151-383%) and image noise was significantly lower (69%, 59-78%) than on FBP images at the same radiation dose (both p < 0.05). On MBIR 10% images, CNR (3.3 ± 0.3) was significantly higher and noise (15 ± 1HU) significantly lower than on FBP 100% images (2.5 ± 0.1; 21 ± 1 HU). On 100% images, lesion attenuation was significantly lower with MBIR than with FBP (mean difference -2 HU). Low-contrast detectability and qualitative results were similar with MBIR 50% and FBP 100%. CONCLUSION: Low-contrast detectability with MBIR 50% and FBP 100% were equal. Quantitative parameters on even lower dose MBIR images are superior to 100%-dose FBP images. Some attenuation values differ significantly with MBIR compared with FBP.

[Epicardial fat: Imaging and implications for diseases of the cardiovascular system]. / Epikardiales Fett : Bildgebung und Bedeutung für Erkrankungen des kardiovaskulären Systems.

Since the discovery of the obese (ob) gene product leptin, fat has been considered an endocrine organ. Especially epicardial fat has gained increasing attention in recent years. The epicardial fat plays a major role in fat metabolism; however, harmful properties have also been reported. Echocardiography, computed tomography and cardiac magnetic resonance imaging are the non-invasive tools used to measure epicardial fat volume. This review briefly introduces the basic physiological and pathophysiological considerations concerning epicardial fat. The main issue of this review is the presentation of non-invasive measurement techniques of epicardial fat using various imaging modalities and a literature overview of associations between epicardial fat and common cardiovascular diseases.

Advanced modelled iterative reconstruction for abdominal CT: qualitative and quantitative evaluation.

AIM: To determine qualitative and quantitative image-quality parameters in abdominal imaging using advanced modelled iterative reconstruction (ADMIRE) with third-generation dual-source 192 section CT. MATERIALS AND METHODS: Forty patients undergoing abdominal portal-venous CT at different tube voltage levels (90, 100, 110, and 120 kVp, n = 10 each) and 10 consecutive patients undergoing abdominal non-enhanced low-dose CT (100 kVp, 60 mAs) using a third-generation dual-source 192 section CT machine in the single-source mode were included. Images were reconstructed with filtered back projection (FBP) and ADMIRE (strength levels 1-5). Two blinded, independent readers subjectively determined image noise, artefacts, visibility of small structures, and image contrast, and measured attenuation in the liver, spleen, kidney, muscle, fat, and urinary bladder, and objective image noise. RESULTS: Subjective noise was significantly lower and image contrast significantly higher for each increasing ADMIRE strength level and also for ADMIRE 1 compared to FBP (all, p < 0.001). No significant differences were found for artefact and visibility ratings among image sets (all, p > 0.05). Attenuation was similar across tube voltage-image datasets in all anatomical regions (all, p > 0.05). Objective noise was significantly lower for each increasing ADMIRE strength level, and for ADMIRE 1 compared to FBP (all, p < 0.001, maximal reduction 53%). Independent predictors of noise were tube voltage (p < 0.05) and current (p < 0.001), diameter (p < 0.05), and reconstruction algorithm (p<0.001); the amount of noise reduction was related only to the reconstruction algorithm (p < 0.001). CONCLUSION: Abdominal CT using ADMIRE results in an improved image quality with lower image noise as compared with FBP, while the attenuation of various anatomical regions remains constant among reconstruction algorithms.

CT metal artefact reduction for internal fixation of the proximal humerus: value of mono-energetic extrapolation from dual-energy and iterative reconstructions.

AIM: To assess the value of dual-energy computed tomography (DECT) and an iterative frequency split-normalized metal artefact reduction (IFS-MAR) algorithm compared to filtered back projections (FBP) from single-energy CT (SECT) for artefact reduction in internally fixated humeral fractures. MATERIALS AND METHODS: Six internally fixated cadaveric humeri were examined using SECT and DECT. Data were reconstructed using FBP, IFS-MAR, and mono-energetic DECT extrapolations. Image analysis included radiodensity values and qualitative evaluation of artefacts, image quality, and level of confidence for localizing screw tips. RESULTS: Radiodensity values of streak artefacts were significantly different (p < 0.05) between FBP (-104 ± 222) and IFS-MAR (73 ± 122), and between FBP and DECT (32 ± 151), without differences between IFS-MAR and DECT (p < 0.553). Compared to FBP, qualitative artefacts were significantly reduced using IFS-MAR (p < 0.001) and DECT (p < 0.05), without significant differences between IFS-MAR and DECT (p < 0.219). Image quality significantly (p = 0.016) improved for IFS-MAR and DECT compared to FBP, without significant differences between IFS-MAR and DECT (p < 0.553). The level of confidence for screw tip localization was assessed as best for DECT in all cases. CONCLUSION: Both IFS-MAR in SECT and mono-energetic DECT produce improved image quality and a reduction of metal artefacts. Screw tip positions can be most confidently assessed using DECT.

[Thyroid-like follicular carcinoma of the kidney: a separate tumor entity?]. / Das schilddrüsenähnliche follikuläre Nierenzellkarzinom: Eine eigene Tumorentität?

Thyroid-like follicular carcinoma of the kidney is postulated as a potentially new entity of renal tumor based on nine previously published case reports. This tumor entity is not yet integrated into the classification of tumors of the World Health Organization (WHO). In this article a new case of thyroid-like follicular carcinoma of kidney is described which was incidentally detected at autopsy. The 58-year-old patient died of complications of acute myeloid leukemia after chemotherapy and also had prostatic adenocarcinoma. The renal tumor in the left kidney had a diameter of 3 cm and showed a grey-brown cut surface. Histologically, the tumor presented with a typical thyroid-like microfollicular and macrofollicular structure filled with eosinophilic, colloid-like material with calcification. Immunohistologically the renal tumor was CD 10 positive and negative for thyroid transcription factor 1 (TTF1) and thyroglobulin. A synopsis of the published case reports indicates that thyroid-like follicular carcinoma of the kidney has a low risk of metastasis. More experience with further cases of thyroid-like follicular renal carcinoma is necessary before a recommendation of a separate tumor entity in the next WHO classification is justified.

Computed tomography for evaluation of abdominal wall hernias-what is the value of the Valsalva maneuver?

PURPOSE: To investigate the differences in the visibility and size of abdominal wall hernias in computed tomography (CT) with and without Valsalva maneuver. METHODS: This single-center retrospective study included consecutive patients who underwent abdominal CTs with Valsalva maneuver between January 2018 and January 2022. Inclusion criteria was availability of an additional non-Valsalva CT within 6 months. A combined reference standard including clinical and surgical findings was used. Two independent, blinded radiologists measured the hernia sac size and rated hernia visibility on CTs with and without Valsalva. Differences were tested with a Wilcoxon signed rank test and McNemar's test. RESULTS: The final population included 95 patients (16 women; mean age 46 ± 11.6 years) with 205 hernias. Median hernia sac size on Valsalva CT was 31 mm compared with 24 mm on non-Valsalva CT (p < 0.001). In 73 and 82% of cases, the hernias were better visible on CT with Valsalva as compared to that without. 14 and 17% of hernias were only visible on the Valsalva CT. Hernia visibility on non-Valsalva CT varied according to subtype, with only 0 and 3% of umbilical hernias not being visible compared with 43% of femoral hernias. CONCLUSIONS: Abdominal wall hernias are larger and better visible on Valsalva CT compared with non-Valsalva CT in a significant proportion of patients and some hernias are only visible on the Valsalva CT. Therefore, this method should be preferred for the evaluation of abdominal wall hernias.

Effect of automatic tube voltage selection on image quality and radiation dose in abdominal CT angiography of various body sizes: a phantom study.

AIM: To assess the effect of an automatic tube voltage selection technique on image quality and radiation dose in abdominal computed tomography (CT) angiography of various body sizes. MATERIALS AND METHODS: An abdominal aortic phantom was filled with iodinated contrast medium and placed into three different cylindrical water containers, which simulated a small, intermediate-sized, and large patient. The phantom was scanned with a standard 120 kVp abdominal CT angiography protocol and with an optimized tube voltage protocol that was modulated by an automatic tube voltage technique. The attenuation of the aorta, background, and image noise was measured, and the contrast-to-noise ratio (CNR) was calculated. Three independent readers assessed the overall image quality. RESULTS: The automatic tube voltage technique selected 70 kVp as the optimal tube voltage for the small phantom, 80 kVp for the intermediate phantom, and 100 kVp for the large phantom. Compared to the standard 120 kVp protocol, the automatic tube voltage selection yielded significantly increased CNR values in the small phantom (15.8 versus 19.4, p < 0.001), intermediate phantom (8.4 versus 8.7, p < 0.05), and large phantom (4.3 versus 4.6, p < 0.01). The automatic tube voltage selection resulted in a 55%, 49%, and 39% reduction in the volume CT dose index (CTDI(vol)) in the small, intermediate, and large phantoms, respectively. The subjective overall image quality of the three phantom sizes at different tube voltages ranged between poor and good. CONCLUSION: Compared to a standard 120 kVp abdominal CT angiography protocol, the automatic tube voltage selection substantially reduced the radiation dose without compromising image quality in various simulated patient sizes.

[Investigation techniques and importance of CT for diagnostics of cardiac valvular diseases]. / Untersuchungstechniken und Stellenwert der CT bei der Diagnostik von Herzklappenerkrankungen.

CLINICAL/METHODICAL ISSUE: Cardiac computed tomography (CT) is the first-line modality for coronary assessment. In addition valvular morphology and function can be evaluated. STANDARD RADIOLOGICAL METHODS: The method of choice for the evaluation of cardiac valves is echocardiography, followed by magnetic resonance imaging. METHODICAL INNOVATIONS: Recent technical improvements and advances in temporal resolution allow a detailed anatomical and functional evaluation of the cardiac valves. PERFORMANCE: Cardiac CT provides an excellent image quality of the aortic and mitral valve thus enabling an evaluation of the morphology. In addition, cardiac CT allows an assessment of aortic valve function with respect to the grading of stenosis and regurgitation. ACHIEVEMENTS: Cardiac CT is not considered the first-line modality for the evaluation of cardiac valves; however, beyond coronary assessment CT provides important information on the morphology and function of cardiac valves. PRACTICAL RECOMMENDATIONS: Cardiac CT can be a useful imaging alternative for patients in whom other more commonly used methods, such as echocardiography and magnetic resonance imaging fail to provide the necessary information.

Diagnostic performance of CT with Valsalva maneuver for the diagnosis and characterization of inguinal hernias.

PURPOSE: Inguinal hernias are mainly diagnosed clinically, but imaging can aid in equivocal cases or for treatment planning. The purpose of this study was to evaluate the diagnostic performance of CT with Valsalva maneuver for the diagnosis and characterization of inguinal hernias. METHODS: This single-center retrospective study reviewed all consecutive Valsalva-CT studies between 2018 and 2019. A composite clinical reference standard including surgery was used. Three blinded, independent readers (readers 1-3) reviewed the CT images and scored the presence and type of inguinal hernia. A fourth reader measured hernia size. Interreader agreement was quantified with Krippendorff's α coefficients. Sensitivity, specificity, and accuracy of Valsalva-CT for the detection of inguinal hernias was computed for each reader. RESULTS: The final study population included 351 patients (99 women) with median age 52.2 years (interquartile range (IQR), 47.2, 68.9). A total of 381 inguinal hernias were present in 221 patients. Sensitivity, specificity, and accuracy were 85.8%, 98.1%, and 91.5% for reader 1, 72.7%, 92.5%, and 81.8% for reader 2, and 68.2%, 96.3%, and 81.1% for reader 3. Hernia neck size was significantly larger in cases correctly detected by all three readers (19.0 mm, IQR 13, 25), compared to those missed by all readers (7.0 mm, IQR, 5, 9; p < 0.001). Interreader agreement was substantial (α = 0.723) for the diagnosis of hernia and moderate (α = 0.522) for the type of hernia. CONCLUSION: Valsalva-CT shows very high specificity and high accuracy for the diagnosis of inguinal hernia. Sensitivity is only moderate which is associated with missed smaller hernias.

Metallic artefact reduction with monoenergetic dual-energy CT: systematic ex vivo evaluation of posterior spinal fusion implants from various vendors and different spine levels.

OBJECTIVES: To evaluate optimal monoenergetic dual-energy computed tomography (DECT) settings for artefact reduction of posterior spinal fusion implants of various vendors and spine levels. METHODS: Posterior spinal fusion implants of five vendors for cervical, thoracic and lumbar spine were examined ex vivo with single-energy (SE) CT (120 kVp) and DECT (140/100 kVp). Extrapolated monoenergetic DECT images at 64, 69, 88, 105 keV and individually adjusted monoenergy for optimised image quality (OPTkeV) were generated. Two independent radiologists assessed quantitative and qualitative image parameters for each device and spine level. RESULTS: Inter-reader agreements of quantitative and qualitative parameters were high (ICC = 0.81-1.00, κ = 0.54-0.77). HU values of spinal fusion implants were significantly different among vendors (P < 0.001), spine levels (P < 0.01) and among SECT, monoenergetic DECT of 64, 69, 88, 105 keV and OPTkeV (P < 0.01). Image quality was significantly (P < 0.001) different between datasets and improved with higher monoenergies of DECT compared with SECT (V = 0.58, P < 0.001). Artefacts decreased significantly (V = 0.51, P < 0.001) at higher monoenergies. OPTkeV values ranged from 123-141 keV. OPTkeV according to vendor and spine level are presented herein. CONCLUSIONS: Monoenergetic DECT provides significantly better image quality and less metallic artefacts from implants than SECT. Use of individual keV values for vendor and spine level is recommended. KEY POINTS: • Artefacts pose problems for CT following posterior spinal fusion implants. • CT images are interpreted better with monoenergetic extrapolation using dual-energy (DE) CT. • DECT extrapolation improves image quality and reduces metallic artefacts over SECT. • There were considerable differences in monoenergy values among vendors and spine levels. • Use of individualised monoenergy values is indicated for different metallic hardware devices.

Impact of myocardial injury on regional left ventricular function in the course of acute myocarditis with preserved ejection fraction: insights from segmental feature tracking strain analysis using cine cardiac MRI.

The aim of this study was to provide insights into myocardial adaptation over time in myocyte injury caused by acute myocarditis with preserved ejection fraction. The effect of myocardial injury, as defined by the presence of late gadolinium enhancement (LGE), on the change of left ventricular (LV) segmental strain parameters was evaluated in a longitudinal analysis. Patients with a first episode of acute myocarditis were enrolled retrospectively. Peak radial (PRS), longitudinal (PLS) and circumferential (PCS) LV segmental strain values at baseline and at follow-up were computed using feature tracking cine cardiac magnetic resonance imaging. The change of segmental strain values in LGE positive (LGE+) and LGE negative (LGE-) segments was compared over a course of 89 ± 20 days. In 24 patients, 100 LGE+ segments and 284 LGE- segments were analysed. Between LGE+ and LGE- segments, significant differences were found for the change of segmental PCS (p < 0.001) and segmental PRS (p = 0.006). LGE + segments showed an increase in contractility, indicating recovery, and LGE- segments showed a decrease in contractility, indicating normalisation after a hypercontractile state or impairment of an initially normal contracting segment. No significant difference between LGE+ and LGE- segments was found for the change in segmental PLS. In the course of acute myocarditis with preserved ejection fraction, regional myocardial function adapts inversely in segments with and without LGE. As these effects seem to counterbalance each other, global functional parameters might be of limited use in monitoring functional recovery of these patients.

[Computed tomography for imaging of pediatric congenital heart disease]. / Die Computertomographie bei der Bildgebung von Kindern mit kongenitalen Herzvitien.

Congenital heart diseases are the most common congenital abnormalities of development. In general, echocardiography and cardiac catheter angiography are considered the gold standard for the evaluation of congenital heart disease. Cardiac magnetic resonance imaging has become an important supplementary imaging modality because of its ability to provide an accurate morphological and functional evaluation. The role of cardiac computed tomography in the imaging of patients with congenital heart disease is becoming increasingly more important due to the development of low radiation dose protocols and improvements in the spatial and temporal resolution. In the preoperative depiction and follow-up after surgical repair of congenital heart diseases, cardiac computed tomography provides detailed information of the heart, the venous and arterial pulmonary circulation as well as systemic arteries. This article reviews the technical aspects of cardiac CT and the modification of examination protocols according to the expected pathology and patient age. The potentials and limitations of the various radiation dose reduction strategies are outlined.

Tube voltage-independent coronary calcium scoring on a first-generation dual-source photon-counting CT-a proof-of-principle phantom study.

To evaluate the accuracy of coronary artery calcium (CAC) scoring at various tube voltages and different monoenergetic image reconstructions on a first-generation dual-source photon-counting detector CT (PCD-CT). A commercially available anthropomorphic chest phantom with calcium inserts was scanned at different tube voltages (90 kV, Sn100kV, 120 kV, and Sn140kV) on a first-generation dual-source PCD-CT system with quantum technology using automatic exposure control with an image quality (IQ) level of 20. The same phantom was also scanned on a conventional energy-integrating detector CT (120 kV; weighted filtered back projection) for reference. Extension rings were used to emulate different patient sizes. Virtual monoenergetic images at 65 keV and 70 keV applying different levels of quantum iterative reconstruction (QIR) were reconstructed from the PCD-CT data sets. CAC scores were determined and compared to the reference. Radiation doses were noted. At an IQ level of 20, radiation doses ranged between 1.18 mGy and 4.64 mGy, depending on the tube voltage and phantom size. Imaging at 90 kV or Sn100kV was associated with a size-dependent radiation dose reduction between 23% and 48% compared to 120 kV. Tube voltage adapted image reconstructions with 65 keV and QIR 3 at 90 kV and with 70 keV and QIR 1 at Sn100kV allowed to calculate CAC scores comparable to conventional EID-CT scans with a percentage deviation of ≤ 5% for all phantom sizes. Our phantom study indicates that CAC scoring with dual-source PCD-CT is accurate at various tube voltages, offering the possibility of substantial radiation dose reduction.

Segmental strain analysis for the detection of chronic ischemic scars in non-contrast cardiac MRI cine images.

Cardiac magnetic resonance imaging (MRI) with late gadolinium enhancement (LGE) is considered the gold standard for scar detection after myocardial infarction. In times of increasing skepticism about gadolinium depositions in brain tissue and contraindications of gadolinium administration in some patient groups, tissue strain-based techniques for detecting ischemic scars should be further developed as part of clinical protocols. Therefore, the objective of the present work was to investigate whether segmental strain is noticeably affected in chronic infarcts and thus can be potentially used for infarct detection based on routinely acquired non-contrast cine images in patients with known coronary artery disease (CAD). Forty-six patients with known CAD and chronic scars in LGE images (5 female, mean age 52 ± 19 years) and 24 gender- and age-matched controls with normal cardiac MRI (2 female, mean age 47 ± 13 years) were retrospectively enrolled. Global (global peak circumferential [GPCS], global peak longitudinal [GPLS], global peak radial strain [GPRS]) and segmental (segmental peak circumferential [SPCS], segmental peak longitudinal [SPLS], segmental peak radial strain [SPRS]) strain parameters were calculated from standard non-contrast balanced SSFP cine sequences using commercially available software (Segment CMR, Medviso, Sweden). Visual wall motion assessment of short axis cine images as well as segmental circumferential strain calculations (endo-/epicardially contoured short axis cine and resulting polar plot strain map) of every patient and control were presented in random order to two independent blinded readers, which should localize potentially infarcted segments in those datasets blinded to LGE images and patient information. Global strain values were impaired in patients compared to controls (GPCS p = 0.02; GPLS p = 0.04; GPRS p = 0.01). Patients with preserved ejection fraction showed also impeded GPCS compared to healthy individuals (p = 0.04). In patients, mean SPCS was significantly impaired in subendocardially (-  5.4% ± 2) and in transmurally infarcted segments (- 1.2% ± 3) compared to remote myocardium (- 12.9% ± 3, p = 0.02 and 0.03, respectively). ROC analysis revealed an optimal cut-off value for SPCS for discriminating infarcted from remote myocardium of - 7.2% with a sensitivity of 89.4% and specificity of 85.7%. Mean SPRS was impeded in transmurally infarcted segments (15.9% ± 6) compared to SPRS of remote myocardium (31.4% ± 5; p = 0.02). The optimal cut-off value for SPRS for discriminating scar tissue from remote myocardium was 16.6% with a sensitivity of 83.3% and specificity of 76.5%. 80.3% of all in LGE infarcted segments (118/147) were correctly localized in segmental circumferential strain calculations based on non-contrast cine images compared to 53.7% (79/147) of infarcted segments detected by visual wall motion assessment (p > 0.01). Global strain parameters are impaired in patients with chronic infarcts compared to controls. Mean SPCS and SPRS in scar tissue is impeded compared to remote myocardium in infarcts patients. Blinded to LGE images, two readers correctly localized 80% of infarcted segments in segmental circumferential strain calculations based on non-contrast cine images, in contrast to only 54% of infarcted segments detected due to wall motion abnormalities in visual wall motion assessment. Analysis of segmental circumferential strain shows a promising method for detection of chronic scars in routinely acquired, non-contrast cine images for patients who cannot receive or decline gadolinium.

Comparison of 3D and 2D late gadolinium enhancement magnetic resonance imaging in patients with acute and chronic myocarditis.

We compared a fast, single breath-hold three dimensional LGE sequence (3D LGE) with an established two dimensional multi breath-hold sequence (2D LGE) and evaluated image quality and the amount of myocardial fibrosis in patients with acute and chronic myocarditis. 3D LGE and 2D LGE (both spatial resolution 1.5 × 1.5 mm2, slice-thickness 8 mm, field of view 350 × 350 mm2) were acquired in 25 patients with acute myocarditis (mean age 40 ± 18 years, 7 female) and 27 patients with chronic myocarditis (mean age 44 ± 22 years, 9 female) on a 1.5 T MR system. Image quality was evaluated by two independent, blinded readers using a 5-point Likert scale. Total myocardial mass, fibrotic mass and total fibrotic tissue percentage were quantified for both sequences in both groups. There was no significant difference in image quality between 3D und 2D acquisitions in patients with acute (p = 0.8) and chronic (p = 0.5) myocarditis. No significant differences between 3D and 2D acquisitions could be shown for myocardial mass (acute p = 0.2; chronic p = 0.3), fibrous tissue mass (acute p = 0.7; chronic p = 0.1) and total fibrous percentage (acute p = 0.4 and chronic p = 0.2). Inter-observer agreement was substantial to almost perfect. Acquisition time was significantly shorter for 3D LGE (24 ± 5 s) as compared to 2D LGE (350 ± 58 s, p < 0.001). In patients with acute and chronic myocarditis 3D LGE imaging shows equal diagnostic quality compared to standard 2D LGE imaging but with significantly reduced acquisition time.

Mitral annular disjunction in patients with severe aortic stenosis: Extent and reproducibility of measurements with computed tomography.

OBJECTIVES: To determine with CT the prevalence and extent of mitral annular disjunction (MAD) in patients undergoing transcatheter aortic valve replacement (TAVR) and its association with mitral valve disease and arrhythmia. METHODS: We retrospectively evaluated 408 patients (median age, 82 years; 186 females) with severe aortic stenosis undergoing ECG-gated cardiac CT with end-systolic data acquisition. Baseline and follow-up data were collected in the context of a national registry. Two blinded, independent observers evaluated the presence of MAD on multi-planar reformations. Maximum MAD distance (left atrial wall-mitral leaflet junction to left ventricular myocardium) and circumferential extent of MAD were assessed on CT using dedicated post-processing software. Associated mitral valve disease was determined with echocardiography. RESULTS: 7.8 % (32/408) of patients with severe aortic stenosis had MAD. The maximum MAD was 3.5 mm (interquartile range: 3.0-4.0 mm). The circumferential extent of MAD comprised 34 ±â€¯15 % of the posterior and 26 ±â€¯12 % of the entire mitral annulus. Intra- and interobserver agreement for the detection of MAD on CT were excellent (kappa: 0.90 ±â€¯0.02 and 0.92 ±â€¯0.02). Mitral regurgitation (p = 1.00) and severe mitral annular calcification (p = 0.29) were similarly prevalent in MAD and non-MAD patients. Significantly more patients with MAD (6/32; 19 %) had mitral valve prolapse compared to those without (6/376; 2 %; p < 0.001). MAD was not associated with arrhythmia before and after TAVR (p > 0.05). CONCLUSIONS: Using CT, MAD was found in 7.8 % of patients with severe aortic stenosis, with a higher prevalence in patients with mitral valve prolapse. We found no association of MAD with arrhythmia before or after TAVR.