Differentiating inflammatory and malignant pulmonary lesions on 3T lung MRI with radiomics of apparent diffusion coefficient maps and T2w derived radiomic feature maps.

Background: Differentiating inflammatory from malignant lung lesions continues to be challenging in clinical routine, frequently requiring invasive methods like biopsy. Therefore, we aimed to investigate if inflammatory and malignant pulmonary lesions could be distinguished noninvasively using radiomics of apparent diffusion coefficient (ADC) maps and radiomic feature maps calculated from T2-weighted (T2w) 3 Tesla (3T) magnetic resonance imaging (MRI) of the lung. Methods: Fifty-four patients with an unclear pulmonary lesion on computed tomography (CT) were prospectively included and examined by 3T MRI with T2w and diffusion-weighted sequences (b values of 50 and 800). ADC maps were calculated automatically. All patients underwent biopsy or bronchoalveolar lavage (BAL). Sixteen patients were excluded (e.g., motion artifacts), leaving 19 patients each with malignant and inflammatory pulmonary lesions. Target lesions were defined by biopsy or as the largest lesion (BAL-based pathogen detection), and two readers placed volumes of interest (VOIs) around the lesions on T2w images and ADC maps. One hundred and seven features were conventionally extracted from the ADC maps using PyRadiomics. T2w images were converted to 107 parametric feature maps per patient using a PyRadiomics-based, pretested software tool developed by our group. VOIs were copied from T2w images to T2 maps for feature quantification. Features were tested for significant differences using the Mann-Whitney U-test. Diagnostic performance was assessed using receiver operating characteristic (ROC) analysis and interreader agreement by intraclass correlation coefficients (ICCs). Results: Fifty-eight features derived from ADC maps differed significantly between malignant and inflammatory pulmonary lesions, with areas under the curve (AUCs) >0.90 for 5 and >0.80 for 27 features, compared with 67 features from T2 maps (5 features with AUCs >0.80). ICCs were excellent throughout. Conclusions: ADC and T2 maps differentiate inflammatory and malignant pulmonary lesions with outstanding (ADC) and excellent (T2w derived feature maps) diagnostic performance. MRI could thus guide the further diagnostic workup and a timely initiation of the appropriate therapy.

The influence of left bundle branch block on myocardial T1 mapping.

Tissue characterisation using T1 mapping has become an established magnetic resonance imaging (MRI) technique to detect myocardial diseases. This retrospective study aimed to determine the influence of left bundle branch block (LBBB) on T1 mapping at 1.5 T. Datasets of 36 patients with LBBB and 27 healthy controls with T1 mapping (Modified Look-Locker inversion-recovery (MOLLI), 5(3)3 sampling) were included. T1 relaxation times were determined on mid-cavity short-axis images. R2 maps were generated as a pixel-wise indicator for the goodness of the fit of T1 maps. R2 values were significantly lower in patients with LBBB than in healthy controls (whole myocardium/septum, 0.997, IQR, 0.00 vs. 0.998, IQR, 0.00; p = 0.008/0.998, IQR, 0.00 vs. 0.999, IQR, 0.00; p = 0.027). Manual correction of semi-automated evaluation tended to improve R2 values but not significantly. Strain analysis was performed and the systolic dyssynchrony index (SDIglobal) was calculated as a measure for left ventricular dyssynchrony. While MRI is generally prone to artefacts, lower goodness of the fit in LBBB may be mainly attributable to asynchronous contraction. Therefore, careful checking of the source data and, if necessary, manual post-processing is important. New techniques might improve the goodness of the fit of T1 mapping by reducing sampling in the motion prone diastole of LBBB patients.

Epicardial fat volume and its association with cardiac arrhythmias in CT coronary angiography.

Purpose: This retrospective study aimed to investigate the epicardial fat volume in cardiac computed tomography (CT), its relationship with cardiac arrhythmias, and its correlation with the coronary artery disease reporting and data system (CAD-RADS) score. Material and methods: Ninety-six patients who underwent CT coronary angiography (CTCA) were included in this study. Patient data, including demographic information, clinical history, and imaging data were collected retrospectively. Epicardial fat volume was quantified using a standardised algorithm, the CAD-RADS scoring system was applied to assess the extent of coronary artery disease (CAD). Descriptive statistics, correlation analyses, and receiver operating characteristics methods were used. Results: The study found a significant correlation between epicardial fat volume and CAD-RADS score (r2 = 0.31; p < 0.001), indicating the known influence of epicardial fat on CAD risk. Moreover, patients with higher epicardial fat volumes were more likely to experience cardiac tachyarrhythmia (p < 0.001). Receiver operating characteristic analysis established a threshold value of 123 cm3 for epicardial fat volume to predict tachyarrhythmia with 80% sensitivity (AUC = 0.69). Conclusions: In this study a volume of at least 123 cm3 epicardial fat in native coronary calcium scans is associated with cardiac tachyarrhythmia. In these patients, careful selection of suitable imaging protocols is advised.

The role of parametric feature maps to correct different volume of interest sizes: an in vivo liver MRI study.

BACKGROUND: Different volume of interest (VOI) sizes influence radiomic features. This study examined if translating images into feature maps before feature sampling could compensate for these effects in liver magnetic resonance imaging (MRI). METHODS: T1- and T2-weighted sequences from three different scanners (two 3-T scanners, one 1.5-T scanner) of 66 patients with normal abdominal MRI were included retrospectively. Three differently sized VOIs (10, 20, and 30 mm in diameter) were drawn in the liver parenchyma (right lobe), excluding adjacent structures. Ninety-three features were extracted conventionally using PyRadiomics. All images were also converted to 93 parametric feature maps using a pretested software. Agreement between the three VOI sizes was assessed with overall concordance correlation coefficients (OCCCs), while OCCCs > 0.85 were rated reproducible. OCCCs were calculated twice: for the VOI sizes of 10, 20, and 30 mm and for those of 20 and 30 mm. RESULTS: When extracted from original images, only 4 out of the 93 features were reproducible across all VOI sizes in T1- and T2-weighted images. When the smallest VOI was excluded, 5 features (T1-weighted) and 7 features (T2-weighted) were reproducible. Extraction from parametric maps increased the number of reproducible features to 9 (T1- and T2-weighted) across all VOIs. Excluding the 10-mm VOI, reproducibility improved to 16 (T1-weighted) and 55 features (T2-weighted). The stability of all other features also increased in feature maps. CONCLUSIONS: Translating images into parametric maps before feature extraction improves reproducibility across different VOI sizes in normal liver MRI. RELEVANCE STATEMENT: The size of the segmented VOI influences the feature quantity of radiomics, while software-based conversion of images into parametric feature maps before feature sampling improves reproducibility across different VOI sizes in MRI of normal liver tissue. KEY POINTS: • Parametric feature maps can compensate for different VOI sizes. • The effect seems dependent on the VOI sizes and the MRI sequence. • Feature maps can visualize features throughout the entire image stack.

[Epiploic appendagitis: an uncommon and nonsurgical cause of abdominal pain]. / Appendagitis epiploica: eine seltene und nichtchirurgische Ursache abdomineller Schmerzen.

BACKGROUND: Epiploic appendagitis (AE) is a rare cause of acute abdomen and is often misdiagnosed as other common causes of acute abdomen, such as acute appendicitis, cholecystitis or diverticulitis due to its low incidence and its nonspecific clinical picture. This study presents the clinical course of AE and typical radiological features for an early and correct diagnosis in order to emphasize the importance of an early and correct diagnosis of AE. METHODS: This is a retrospective review of 43 patients diagnosed with AE between June 2010 and September 2022 at the Charité - University Hospital Berlin, Campus Benjamin Franklin. The medical records were reviewed regarding clinical und radiological features, anatomical location of the AE und treatment methods. RESULTS: A total of 43 patients (29 male, 11 female) were diagnosed with AE and almost all patients presented with abdominal pain, except in 8 cases (18.6%). Specific findings in computer tomography (CT) with a typical picture of AE were found in 33 patients (76.7%). AE was mostly localized in the left colon: 12 were found in the sigmoid colon (27.9%), 16 in the descending colon (37.2%) and 5 at the junction of the descending colon and the sigmoid colon (11.6%). Of the patients 28 (65.1%) were admitted for conservative treatment and the rest of the patients were treated as outpatients. No patient underwent surgery, all were treated with analgesics (NSAID) and 17 patients received antibiotics in addition. CONCLUSION: AE is a self-limiting disease and a common mimic of other serious causes of abdominal pain. Due to the emergence of the widespread use of imaging modalities, an early diagnosis of AE and a conservative approach as first choice of treatment in patients with AE could be established.

Cardiac magnetic resonance imaging in patients with left bundle branch block: Patterns of dyssynchrony and implications for late gadolinium enhancement imaging.

Background: Left bundle branch block (LBBB) is a ventricular conduction delay with high prevalence. Aim of our study is to identify possible recurring patterns of artefacts in late gadolinium enhancement (LGE) imaging in patients with LBBB who undergo cardiac magnetic resonance imaging (MRI) and to define parameters of mechanical dyssynchrony associated with artefacts in LGE images. Materials and methods: Fifty-five patients with LBBB and 62 controls were retrospectively included. Inversion time (TI) scout and LGE images were reviewed for artefacts. Dyssynchrony was identified using cardiac MRI by determining left ventricular systolic dyssynchrony indices (global, septal segments, and free wall segments) derived from strain analysis and features of mechanical dyssynchrony (apical rocking and septal flash). Results: Thirty-seven patients (67%) with LBBB exhibited inhomogeneous myocardial nulling in TI scout images. Among them 25 (68%) patients also showed recurring artefact patterns in the septum or free wall on LGE images and artefacts also persisted in 18 (72%) of those cases when utilising phase sensitive inversion recovery. Only the systolic dyssynchrony index of septal segments allowed differentiation of patient subgroups (artefact/no artefact) and healthy controls (given as median, median ± interquartile range); LBBB with artefact: 10.44% (0.44-20.44%); LBBB without artefact: 6.82% (-2.18-15.83%); controls: 4.38% (1.38-7.38%); p < 0.05 with an area under the curve of 0.863 (81% sensitivity, 89% specificity). Septal flash and apical rocking were more frequent in the LBBB with artefact group than in the LBBB without artefact group (70 and 62% versus 33 and 17%; p < 0.05). Conclusion: Patients with LBBB show recurring artefact patterns in LGE imaging. Use of strain analysis and evaluation of mechanical dyssynchrony may predict the occurrence of such artefacts already during the examination and counteract misinterpretation.

The effect of smoking on quantification of aortic stiffness by ultrasound time-harmonic elastography.

Smoking is a significant cardiovascular risk factor that causes stiffening of the central arteries, especially the aorta. While vessel stiffness can be determined indirectly by measuring pulse wave velocity, elastography allows image-based determination of vessel stiffness while at the same time providing information on vascular morphology. This study compares abdominal aortic wall stiffness as measured by ultrasound time-harmonic elastography (THE) in fifteen smokers and fifteen age-matched non-smoking controls without a history of cardiovascular disease. Smokers had a significantly higher abdominal aortic wall stiffness with a mean shear wave speed of 2.66 m/s (95% confidence interval (CI) 2.59-2.72 m/s) compared to 2.40 m/s (95% CI 2.34-2.47 m/s) (p < 0.01) in the group of non-smokers. All other baseline characteristics including aortic diameter showed no significant differences. Inter-rater variability was excellent with an intraclass correlation coefficient of 0.99 (95% CI 0.98-0.99). Our results show that THE is sensitive to subclinical stiffening of the aorta in young and middle-aged smokers even before morphological changes occur and may therefore has the potential to serve as a screening tool for early aortic abnormalities and longitudinal risk factors for cardiovascular health.

Enhancing the stability of CT radiomics across different volume of interest sizes using parametric feature maps: a phantom study.

BACKGROUND: In radiomics studies, differences in the volume of interest (VOI) are often inevitable and may confound the extracted features. We aimed to correct this confounding effect of VOI variability by applying parametric maps with a fixed voxel size. METHODS: Ten scans of a cup filled with sodium chloride solution were scanned using a multislice computed tomography (CT) unit. Sphere-shaped VOIs with different diameters (4, 8, or 16 mm) were drawn centrally into the phantom. A total of 93 features were extracted conventionally from the original images using PyRadiomics. Using a self-designed and pretested software tool, parametric maps for the same 93 features with a fixed voxel size of 4 mm3 were created. To retrieve the feature values from the maps, VOIs were copied from the original images to preserve the position. Differences in feature quantities between the VOI sizes were tested with the Mann-Whitney U-test and agreement with overall concordance correlation coefficients (OCCC). RESULTS: Fifty-five conventionally extracted features were significantly different between the VOI sizes, and none of the features showed excellent agreement in terms of OCCCs. When read from the parametric maps, only 8 features showed significant differences, and 3 features showed an excellent OCCC (≥ 0.85). The OCCCs for 89 features substantially increased using the parametric maps. CONCLUSIONS: This phantom study shows that converting CT images into parametric maps resolves the confounding effect of VOI variability and increases feature reproducibility across VOI sizes.

Multifrequency magnetic resonance elastography-based tomoelastography of the parotid glands-feasibility and reference values.

OBJECTIVES: Accurate radiological differentiation of parotid tumors remains challenging despite recent technical advances in quantitative medical imaging. Multifrequency magnetic resonance elastography (MRE) could provide additional information on viscoelastic properties of normal and abnormal biological tissues. This study investigates the feasibility of MRE of the parotid glands in healthy participants and provides first reference values. METHODS: 20 healthy participants underwent multifrequency MRE of both parotid glands at 3 Tesla. Shear waves at frequencies of 25, 30, 40, and 50 Hz were introduced into the participants' heads through the occiput using pressurized-air actuators. Shear wave speed (SWS) and loss angle of the shear modulus (φ) were reconstructed by tomoelastography post-processing as surrogate parameters for tissue stiffness and viscosity or fluidity. 10 participants underwent repeated MRE to determine test-retest reliability based on intraclass correlation coefficients. RESULTS: All MRE datasets acquired could be included in the analysis. Mean SWS was 0.97 ± 0.13 m/s, and mean φ was 0.59 ± 0.05 rad, each for both sides combined and without notable lateral difference (p = 0.88/0.87). Test-retest reliability was good for SWS (ICC = 0.84 for both sides/ICC = 0.77 for the right side/ICC = 0.79 for the left side) and good to excellent for φ(ICC = 0.94/0.86/0.90). CONCLUSIONS: Multifrequency MRE of the parotid glands is feasible and reliable. This technique, therefore, is a promising method for investigating the viscoelastic properties of salivary gland tumors in future studies.

Impact of double reading on NI-RADS diagnostic accuracy in reporting oral squamous cell carcinoma surveillance imaging - a single-center study.

OBJECTIVES: The Neck Imaging Reporting and Data System (NI-RADS) is an increasingly utilized risk stratification tool for imaging surveillance after treatment for head and neck cancer. This study aims to measure the impact of supervision by subspecialized radiologists on diagnostic accuracy of NI-RADS when initial reading is performed by residents. METHODS: 150 CT and MRI datasets were initially read by two trained residents, and then supervised by two subspecialized radiologists. Recurrence rates by NI-RADS category were calculated, and receiver operating characteristic (ROC) curves were plotted. After dichotomization of the NI-RADS system (category 1 vs categories 2 + 3+4 and categories 1 + 2 vs 3 + 4), sensitivity, specificity, positive and negative predictive value were calculated. RESULTS: 26% of the reports were modified by the supervising radiologists. Area under the curve of ROC plots values of the supervision session were higher than those of the initial reading session for both the primary site (0.89 vs 0.86) and the neck (0.94 vs 0.91), but the difference was not statistically significant. For dichotomized NI-RADS category assignments, differences between the initial reading and the supervision session were statistically significant regarding specificity and PPV for the primary site (1 + 2 vs 3 + 4 and 1 vs 2 + 3+4) or even for both sites combined (1 vs 2 + 3+4). CONCLUSION: NI-RADS enables trained resident radiologists to report surveillance imaging in patients with treated oral squamous cell carcinoma with high discriminatory power. Additional supervision by a subspecialized head and neck radiologist particularly improves specificity of radiological reports.

Retrospective Evaluation of NI-RADS for Detecting Postsurgical Recurrence of Oral Squamous Cell Carcinoma on Surveillance CT or MRI.

BACKGROUND. Imaging surveillance is important for the early diagnosis of recurrence after definitive treatment of oral squamous cell carcinoma (OSCC). The Neck Imaging Reporting and Data System (NI-RADS) includes a standardized template for surveillance imaging and categorizes probability of recurrence at the primary site and in the neck (cervical lymph nodes) by assigning categories of 1 (no evidence of recurrence), 2 (low suspicion, subdivided into 2a and 2b for the primary site), 3 (high suspicion), and 4 (definite recurrence). OBJECTIVE. The aim of this study was to determine the rate of locoregional and nodal OSCC recurrence stratified by NI-RADS category among patients undergoing surveillance CT or MRI. METHODS. This retrospective study included 158 patients enrolled in an institutional surveillance program after resection of OSCC with curative intent. A total of 503 contrast-enhanced CT or MRI examinations performed during surveillance were evaluated. Each examination was randomly assigned to one of four radiologists with expertise in head and neck imaging, who provided NI-RADS categories for the primary site and the neck (1006 assigned NI-RADS categories). NI-RADS performance in identifying recurrence was assessed by ROC curve analysis. All four readers evaluated 50 randomly assigned cases to determine interreader agreement by use of the Kendall W statistic. RESULTS. Cancer recurrence was confirmed in 7.6% (38/503) of cases for the primary site and in 6.2% (31/503) for the neck. For the primary site, recurrence rates were 1.0% in NI-RADS category 1, 7.1% in category 2a, 5.6% in category 2b, 66.7% in category 3, and 100.0% in category 4. For the neck, recurrence rates were 0.5% in category 1, 7.0% in category 2, 80.0% in category 3, and 100.0% in category 4. NI-RADS had AUC values of 0.934 for the primary site and 0.959 for the neck. Interreader agreement was 0.67 for the primary site and 0.81 for the neck. CONCLUSION. NI-RADS offers excellent discriminatory power in detection of OSCC recurrence, both for the primary site and the neck. CLINICAL IMPACT. Radiologists and maxillofacial surgeons should implement NI-RADS in surveillance regimens for postoperative OSCC to help detect recurrences in an effective and standardized manner using imaging.

Steady-State Multifrequency Magnetic Resonance Elastography of the Thoracic and Abdominal Human Aorta-Validation and Reference Values.

OBJECTIVES: The aim of this study was to investigate the potential of stroboscopic-wavefield-sampling-based multifrequency magnetic resonance elastography (sMRE) for quantifying the stiffness of the human thoracic and abdominal aorta in vivo. MATERIALS AND METHODS: The sMRE of the thoracic and abdominal aorta was performed at 1.5 T field strength in 20 healthy volunteers aged 27 to 77 years (3 women; median age, 33 years; interquartile range [IQR], 16 years). Compound maps of shear wave speed (SWS) were reconstructed and evaluated during the diastolic phase in 3 anatomical regions: ascending thoracic aorta (AA), descending thoracic aorta (AD), and abdominal aorta (AAb). The SWS maps were read by 2 readers. Blood pressure and pulse wave velocity were determined noninvasively before sMRE. Data are given as median (IQR) and were compared using the Kruskal-Wallis and Wilcoxon rank sum tests. Intraclass correlation was used to determine interobserver and intraobserver agreement, as well as reproducibility. Multiple linear regression analysis was performed to evaluate effects of age, sex, vessel diameter, blood pressure, pulse wave velocity, and aortic segment on measured SWS. RESULTS: All 20 participants underwent successful sMRE, resulting in a total of 60 aortic segments. The median SWS (IQR) of AA, AD, and AAb was 1.62 (0.16) m/s, 2.40 (0.24) m/s, and 2.48 (0.58) m/s, respectively. The SWS in AA was significantly lower (P < 0.001), and no differences in SWS (P = 0.67) were found between AD and AAb. Interobserver and intraobserver agreement, as well as reproducibility, was excellent, with intraclass correlation coefficients ranging between 0.957 and 0.998. A significant but weak influence of age on measured SWS was found, which increased from AA to AD and AAb (R = 0.229, 0.275, 0.377, respectively; P = 0.001-0.005). CONCLUSIONS: Quantification of aortic stiffness in different segments of the human aorta is possible with sMRE. Our results correlate well with known aortic stiffness differences in different anatomical locations and demonstrate the potential of sMRE for clinical stiffness measurement of the thoracoabdominal aorta, which may allow detection of physiological variation and cardiovascular diseases.

Effect of Different Iodine Concentrations on Patient-Reported Discomfort in Contrast-Enhanced Computed Tomography: A Prospective Comparative Trial.

PURPOSE: Reducing contrast media injection speed while maintaining iodine flux is a promising workaround to lower or avoid contrast media-related discomfort during CT examinations. This approach demands contrast media with a higher concentration to guarantee excellent image quality. It remains unclear whether these concentration changes affect the patient's experience. Thus, the aim of this study was to evaluate the influence of different concentrations of intravenous iodinated contrast media on patient discomfort during and after contrast media delivery. MATERIALS AND METHODS: Patients were randomized to receive either Iomeprol 400 mg/ml (group A) or 300 mg/ml (group B) during routinely scheduled CT examinations at our department. The iodine delivery rate and injection time were kept constant in both groups. After examination, study subjects completed a digital questionnaire on different CM-related sensation items using digital visual analogue scales. RESULTS: 253 consecutive patients were enrolled in a 6-month period. Most of the patients reported heat sensation in both groups (mean VAS: 5.3 mm in group A vs. 5.0 mm in group B, p = 0.5). Taste sensation also did not differ significantly between both groups (2.4 mm vs. 2.0 mm, p = 0.08). Pain sensation was reported to be significantly lower in group B patients (1.3 mm vs. 1.0 mm, p = 0.005), even though pain sensation in general was reported on a very low level. Other injection-related sensations were rarely reported. CONCLUSION: Patient-reported discomfort during intravenous injection of high-concentration contrast media (400 mg/ml) was low and only marginally different when compared to the injection of contrast media with a lower concentration. The injection of highly concentrated contrast media showed comparable overall patient acceptance, allowing a reduction of the injection speed and volume during examinations. KEY POINTS: · Patient-reported, contrast-related discomfort was very low in this study.. · High-concentration contrast media (HCCM) showed comparable overall patient acceptance.. · HCCM allow a reduction of injection speeds while keeping iodine flux constant.. CITATION FORMAT: · Vahldiek JL, Schaafs LA, Niehues BK et al. Effect of Different Iodine Concentrations on Patient-Reported Discomfort in Contrast-Enhanced Computed Tomography: A Prospective Comparative Trial. Fortschr Röntgenstr 2020; 192: 945 - 951.

Diagnosis of Left Ventricular Diastolic Dysfunction Using Cardiac Magnetic Resonance Imaging: Comparison of Volume-Time Curves Derived from Long- and Short-Axis Cine Steady-State Free Precession Datasets.

PURPOSE: To evaluate the diagnostic performance of diastolic function parameters derived from long-axis (LAX) planimetry compared with short-axis (SAX) volumetry in cardiac magnetic resonance imaging. MATERIALS AND METHODS: Cine steady-state free precession (SSFP) datasets of 15 healthy participants (8 young and 7 middle aged) and 25 patients with echocardiographically proven diastolic dysfunction (9 mild, 9 moderate, and 7 severe) were retrospectively included. Volume-time curves for assessing left ventricular (LV) function were obtained by manually contouring the LV endocardial borders in SAX and LAX datasets. The time needed for contouring was recorded for each dataset. The following LV parameters were determined: end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF), myocardial mass (MM), time to peak filling rate (TPFR), normalized peak filling rate (nPFR), and the ratio of early to late peak filling rate (E/A ratio). A Wilcoxon signed-rank test was used to compare subgroups based on age and severity of diastolic dysfunction for statistical differences. Intraclass correlation coefficients were used to assess intermethod and interobserver reliability. RESULTS: Accuracy for the diagnosis of diastolic dysfunction was highest for E/A (mild diastolic dysfunction) and nPFR (any stage of diastolic dysfunction) derived from LAX datasets (E/A: area under the curve (AUC) = 0.97, sensitivity of 68 % and specificity of 100 %; nPFR: AUC = 0.84, sensitivity of 84 % and specificity of 80 %). Diastolic parameters showed a moderate to good intraclass correlation between both methods. The mean differences in EDV, ESV, EF, and MM were 5.3 ml, 1.9 ml, 3.5 %, and 11 g, respectively (each p < 0.001). Significantly less time was needed to derive volume-time curves from LAX images (median 14:45 min, interquartile range 14:15-15:53 min versus median 29:25 min, interquartile range 28:12-32:22 min; p = 0.001). The interobserver reliability was generally good to excellent. CONCLUSION: Diastolic function parameters derived from left ventricular LAX planimetry have high diagnostic performance and can be obtained in significantly less time compared with SAX volumetry. These findings may pave the way for routine use of LAX planimetry in the clinical diagnosis of diastolic dysfunction. KEY POINTS: · Diastolic function parameters derived from long-axis datasets have high diagnostic performance.. · Generation of volume-time curves using long-axis datasets requires significantly less time.. · This time savings may allow use of cardiac MRI for the diagnosis of diastolic dysfunction in the clinical routine.. CITATION FORMAT: · Schaafs LA, Wyschkon S, Elgeti M et al. Diagnosis of Left Ventricular Diastolic Dysfunction Using Cardiac Magnetic Resonance Imaging: Comparison of Volume-Time Curves Derived from Long- and Short-Axis Cine Steady-State Free Precession Datasets. Fortschr Röntgenstr 2020; 192: 764 - 775.

Quantification of Aortic Stiffness by Ultrasound Time-Harmonic Elastography: The Effect of Intravascular Pressure on Elasticity Measures in a Porcine Model.

OBJECTIVES: The aim of this study was to investigate blood pressure dependency of ultrasound time-harmonic elastography (THE) for quantification of aortic stiffness. MATERIALS AND METHODS: Thoracoabdominal aortas were surgically removed from 9 healthy domestic pigs and prepared for elastographic experiments. All vessels were connected to a saline-filled water column with adjustable height and pressurized over a range of 0 to 110 mm Hg in 10 mm Hg increments to simulate different levels of mean arterial pressure. In addition, 3 of the 9 aortas were soaked in 4% buffered formaldehyde for 60 minutes to simulate pathologic aortic stiffening. Ultrasound THE was performed in each vessel at each pressure level. For each pressure level, shear-wave speed (SWS) as a measure of aortic wall stiffness and luminal diameter were recorded. The pressure range between 30 and 110 mm Hg was used for statistical evaluation as it reflects a physiological mean arterial pressure range. Linear regression analysis and multivariate analysis with a general linear model were performed to evaluate the influence of increasing intravascular pressure and vessel diameter on measured SWS. RESULTS: Median SWS in formalin-soaked aortas was significantly higher with 3.22 m/s (interquartile range [IQR], 0.01 m/s) versus 2.14 m/s (IQR, 0.09) at 30 mm Hg and 3.38 m/s (IQR, 0.01 m/s) versus 2.28 m/s (IQR, 0.07 m/s) at 110 mm Hg (each P = 0.01). Using linear regression analysis, an increase of aortic wall SWS of 0.017 m/s per 10 mm Hg intraluminal pressure was found in untreated aortas, whereas SWS increased by 0.020 m/s per 10 mm Hg in formalin-soaked aortas (both P = 0.001). The percentage of SWS caused by intraluminal pressure was 1.89% in formalin-soaked aortas and 2.50% in untreated aortas at 30 mm Hg and 6.61% for formalin-soaked aortas and 8.60% for untreated aortas at 110 mm Hg. Multivariate analysis showed no significant interaction of luminal diameter and measured SWS (P = 0.893). CONCLUSIONS: In our model, aortic stiffness measurements by ultrasound time-harmonic elastography are influenced to a small extent by mean arterial pressure in a range of 1.89% to 8.60%. These findings emphasize the potential of ultrasound THE for measuring the intrinsic stiffness of the aortic wall in clinical routine.

Ultrasound Time-Harmonic Elastography of the Aorta: Effect of Age and Hypertension on Aortic Stiffness.

OBJECTIVES: The aim of this study was to investigate ultrasound time-harmonic elastography for quantifying aortic stiffness in vivo in the context of aging and arterial hypertension. MATERIALS AND METHODS: Seventy-four participants (50 healthy participants and 24 participants with long-standing hypertension) were prospectively included between January 2018 and October 2018, and underwent ultrasound time-harmonic elastography of the upper abdominal aorta. Compound maps of shear-wave speed (SWS) as a surrogate of tissue stiffness were generated from multifrequency wave fields covering the full field-of-view of B-mode ultrasound. Blood pressure and pulse wave velocity were measured beforehand. Interobserver and intraobserver agreement was determined in 30 subjects. Reproducibility of time-harmonic elastography was assessed in subgroups with repeated measurements after 20 minutes and after 6 months. Linear regression analysis, with subsequent age adjustment of SWS obtained, receiver operating characteristic analysis, and intraclass correlation coefficients (ICCs) were used for statistical evaluation. RESULTS: Linear regression analysis revealed a significant effect of age on SWS with an increase by 0.024 m/s per year (P < 0.001). Age-adjusted SWS was significantly greater in hypertensives (0.24 m/s; interquartile range [IQR], 0.17-0.40 m/s) than in healthy participants (0.07 m/s; IQR, -0.01 to 0.06 m/s; P < 0.001). A cutoff value of 0.15 m/s was found to differentiate best between groups (area under the receiver operating characteristic curve, 0.966; 95% confidence interval, 0.93-1.0; P < 0.001; 83% sensitivity and 98% specificity). Interobserver and intraobserver variability was excellent (ICC, 0.987 and 0.937, respectively). Reproducibility was excellent in the short term (ICC, 0.968; confidence interval, 0.878-0.992) and good in the long term (ICC, 0.844; confidence interval, 0.491-0.959). CONCLUSIONS: Ultrasound time-harmonic elastography of the upper abdominal aorta allows quantification of aortic wall stiffness in vivo and shows significantly higher values in patients with arterial hypertension.

Quantitative Time-Harmonic Ultrasound Elastography of the Abdominal Aorta and Inferior Vena Cava.

The purpose of this study was to evaluate the sensitivity of quantitative time-harmonic ultrasound elastography (THE) of the inferior vena cava (IVC) and abdominal aorta (AA) to changes in central volume status. THE of the IVC and AA was performed in 20 healthy volunteers before and after oral intake of 1 L of water and before or during passive leg raising to augment venous filling. Compound maps of shear wave speed (SWS) as surrogate measures of vessel wall stiffness were generated within the full field of view from multifrequency harmonic wave fields. SWS was measured in regions of the IVC and AA. Blood pressure, stroke volume, cardiac output and pulse wave velocity were recorded. Statistical significance of SWS changes was tested using one-way repeated-measures analysis of variance. SWS measured in the IVC increased from 1.71 ± 0.1 m/s before water intake to 1.82 ± 0.1 m/s during passive leg raising and, further, to 1.87 ± 0.1 m/s after hydration and to 1.95 ± 0.1 m/s with hydration plus passive leg raising (p < 0.001). SWS in the AA did not change significantly after hydration (2.14 ± 0.13 m/s vs. 2.15 ± 0.16 m/s; p = 0.792). SWS was significantly higher in the AA than in the IVC across all experiments (p < 0.001). Water drinking did not significantly influence blood pressure, pulse wave velocity and cardiac output (all p values >0.1), whereas stroke volume increased significantly (p = 0.031). Time-harmonic ultrasound elastography enables quantification of the wall stiffness of the large abdominal vessels and is sensitive to different volume and pressure states in the IVC.

LOW-DOSE COMPUTED TOMOGRAPHY OF THE PARANASAL SINUSES: PERFORMANCE OF TWO DIFFERENT ITERATIVE RECONSTRUCTION ALGORITHMS.

To evaluate the performance of two iterative reconstruction algorithms in low-dose paranasal sinus computed tomography (CT). Sinus CT scans were reconstructed using Adaptive Iterative Dose Reduction 3D (AIDR 3D, n = 36 patients) or Sinogram Affirmed Iterative Reconstruction (SAFIRE, n = 32 patients). Reconstructed images were evaluated regarding subjective image quality, depiction of anatomic landmarks and noise (HU). Dose-length product (DLP), calculated effective dose (ED) and CT dose index (CTDIvol) were documented for each scan. Images were not significantly different in subjective image quality (p = 0.09) and conspicuity of anatomic landmarks (p = 0.28). Noise was significantly lower in images reconstructed with AIDR 3D (p = 0.012). DLP, ED and CTDIvol were significantly lower in the SAFIRE datasets (each p < 0.001). The results indicate that iterative reconstruction, independent of the manufacturer, enables for imaging the paranasal sinuses with an ED below 0.1 mSv while ensuring diagnostic image quality.

Periradicular infiltration of the lumbar spine: is iterative reconstruction software necessary to establish ultra-low-dose protocols? A quantitative and qualitative approach.

PURPOSE: Computed tomography (CT)-guided periradicular infiltration therapy has emerged as an effective treatment option for patients with low back pain. Concern about radiation exposure requires approaches allowing significant dose reduction. The purpose of this study is to evaluate the need for iterative reconstruction software in CT-guided periradicular infiltration therapy with an ultra-low-dose protocol. MATERIALS AND METHODS: One hundred patients underwent CT-guided periradicular infiltration therapy of the lumbar spine using an ultra-low-dose protocol with adaptive iterative dose reduction 3D (AIDR 3D) for image reconstruction. In addition, images were reconstructed with filtered back-projection (FBP). Four experienced raters evaluated both reconstruction types for conspicuity of anatomical and instrumental features important for ensuring safe patient treatment. Image noise was measured as a quantitative marker of image quality. RESULTS: Interrater agreement was good for both AIDR 3D (Kendall's W = 0.83) and FBP (0.78) reconstructions. Readers assigned the same scores for all features and both reconstruction algorithms in 81.3% of cases. Image noise was significantly lower (average SD of 60.07 vs. 99.54, p < 0.05) for AIDR 3D-reconstructed images. CONCLUSION: Although it significantly lowers image noise, iterative reconstruction software is not mandatory to achieve adequate image quality with an ultra-low-dose CT protocol for guiding periradicular infiltration therapy of the lumbar spine.