Michael Meier-Schroers

3D-Dixon MRI based volumetry of peri- and epicardial fat

There is growing evidence that pericardial and epicardial fat volume (PFV, EFV) are associated with cardiovascular risk. We evaluated a novel method for accurate measurement of PFV and EFV using a 3D-Dixon based cardiac magnetic resonance (CMR) approach. An electrocardiography triggered and respiratory navigator gated 3D-gradient echo pulse sequence was used for cardiac Dixon imaging. Based on this sequence, voxels predominantly containing fat were identified and added up for volumetry. After accuracy assessment in phantoms, consisting of muscle tissue and seven different fat samples (50–200xa0ml), the sequence was acquired in 34 healthy volunteers (22 male, BMI range 14–42xa0kg/m2, age range 21–79xa0years) at 1.5xa0T. Analysis was performed independently by two readers who draw two 3D-regions of interest, one for EFV and one for PFV. Additionally, EFV and PFV were compared between overweighted and non-overweighted subjects. The phantom study showed an excellent agreement of measured and true fat volumes (maximum differencexa0=xa06xa0%, linear correlation coefficient Rxa0=xa01.00). PFV over all volunteers was 158.0xa0±xa0126.4xa0ml and EFV was 77.0xa0±xa055.3xa0ml. PFV and EFV were highly correlated (Rxa0=xa00.96). Inter-reader agreement was good with a mean difference of 0.2xa0±xa05.6 and 4.5xa0±xa04.2xa0ml for PFV/EFV, (Rxa0>xa00.99, each). EFV and PFV differed significantly between subjects with BMIxa0>xa025xa0kg/m2 and BMIxa0<xa025xa0kg/m2, nxa0=xa017 each (PFV 219.0xa0±xa0151.8 vs. 96.9xa0±xa044.7xa0ml and EFV 102.3xa0±xa066.3 vs. 51.7xa0±xa023.6xa0ml, pxa0<xa00.001, each). The proposed 3D-Dixon based method allows accurate measurement of cardiac fat volumes. It provides a valuable tool for cardiovascular risk stratification by CMR.

MRI of the lung using the PROPELLER technique: Artifact reduction, better image quality and improved nodule detection

PURPOSEnTo evaluate the benefit of the PROPELLER technique (Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction, MultiVane, MV) for MR imaging of the lung.nnnMATERIALS AND METHODSn30 Participants of a lung cancer screening program were recruited for the comparison of T2-MV and T2-Fast Spin Echo (FSE) sequences at 1.5T. Two readers evaluated artifacts, image quality, and pulmonary lesions. Artifacts and image quality were rated using a four-point scale. Lesion detection was correlated to low-dose computed tomography (CT). Wilcoxon rank-test for ratings of artifacts and image quality, sensitivity and specificity values for lesion detection, and Cohens kappa for inter-rater agreement were used.nnnRESULTSnThe MV sequence showed less pulsation and motion artifacts, and higher image quality (p=0.001 for R1, p=0.002 for R2) than FSE (p<0.001 for both readers, R1 and R2). Inter-rater agreement was excellent for lesion detection (0.84-0.95) and good to excellent for artifacts and image quality (0.66-0.84). 17 patients had lesions <8mm, and 7 had lesions >8mm as seen on CT. For R1 and R2, the MV sequence allowed for higher detection rates of pulmonary lesions <8mm with a sensitivity of 56% (R1) and 59% (R2); the FSE sequence achieved 50% (R1) and 53% (R2). Specificity was also higher for MV with 94% (R1) and 83% (R2) compared to 78% (R1) and 76% (R2). Lesions >8mm were detected with a sensitivity of 100% by both readers on both MV and FSE images. For both readers, specificity for larger lesions was higher on MV images with 100% compared to 96%.nnnCONCLUSIONnThe superior image quality and the very robust artifact reduction make MV a promising technique for MRI of the lung compared to FSE, especially since it is not requiring breathholds. Moreover, MV allows for improved lesion detection.

Differentiation of prostatitis and prostate cancer using the Prostate Imaging—Reporting and Data System (PI-RADS)

PURPOSEnTo determine if prostate cancer (PCa) and prostatitis can be differentiated by using PI-RADS.nnnMATERIALS AND METHODSn3T MR images of 68 patients with 85 cancer suspicious lesions were analyzed. The findings were correlated with histopathology. T2w imaging (T2WI), diffusion weighted imaging (DWI), dynamic contrast enhancement (DCE), and MR-Spectroscopy (MRS) were acquired. Every lesion was given a single PI-RADS score for each parameter, as well as a sum score and a PI-RADS v2 score. Furthermore, T2-morphology, ADC-value, perfusion type, citrate/choline-level, and localization were evaluated.nnnRESULTSn44 of 85 lesions showed PCa (51.8%), 21 chronic prostatitis (24.7%), and 20 other benign tissue such as hyperplasia or fibromuscular tissue (23.5%). The single PI-RADS score for T2WI, DWI, DCE, as well as the aggregated score including and not including MRS, and the PI-RADS v2-score were all significantly higher for PCa than for prostatitis or other tissue (p<0.001). The single PI-RADS score for MRS and the PI-RADS sum score including MRS were significantly higher for prostatitis than for other tissue (p=0.029 and p=0.020), whereas the other parameters were not different. Prostatitis usually presented borderline pathological PI-RADS scores, showed restricted diffusion with ADC≥900mm(2)/s in 100% of cases, was more often indistinctly hypointense on T2WI (66.7%), and localized in the transitional zone (57.1%). An ADC≥900mm(2)/s achieved the highest predictive value for prostatitis (AUC=0.859).nnnCONCLUSIONnProstatitis can be differentiated from PCa using PI-RADS, since all available parameters are more distinct in cases of cancer. However, there is significant overlap between prostatitis and other benign findings, thus PI-RADS is only suitable to a limited extent for the primary assessment of prostatitis. Restricted diffusion with ADC≥900mm(2)/s is believed to be a good indicator for prostatitis. MRS can help to distinguish between prostatitis and other tissue.

In-bore transrectal MRI-guided prostate biopsies: Are there risk factors for complications?

PURPOSEnTo systematically analyze risk factors for complications of in-bore transrectal MRI-guided prostate biopsies (MRGB).nnnMATERIALS AND METHODSn90 patients, who were scheduled for MRGB were included for this study. Exclusion criteria were coagulation disorders, therapy with anticoagulant drugs, and acute infections of the urinary and the lower gastrointestinal tract. Directly after, one week and one year after the biopsy, we assessed biopsy related complications (e.g. hemorrhages or signs of prostatitis). Differences between patients with and without complications were analyzed regarding possible risk factors: age, prostate volume, number of taken samples, biopsy duration, biopsy of more than one lesion, diabetes, arterial hypertension, hemorrhoids, benign prostate hyperplasia, carcinoma or prostatitis (according to histopathological analysis), and lesion localization. Complications were classified according to the Clavien-Dindo classification.nnnRESULTSnWe observed 15 grade I complications in 90 biopsies (16.7%) with slight hematuria in 9 cases (10%), minor vasovagal reactions in 4 cases (4.4%), and urinary retention and positioning-related facial dysesthesia in 1 case each (1.1%). One patient showed acute prostatitis requiring antibiotics as the only grade II complication (1.1%). There were no adverse events that occurred later than one week. Complications grade III or higher such as pelvic abscesses, urosepsis or severe hemorrhages were not seen. There were no significant associations between the assessed risk factors and biopsy-related complications.nnnCONCLUSIONnIn-bore transrectal MRI-guided prostate biopsies can be considered safe procedures in the diagnosis of prostate cancer with very low complication rates. There seem to be no risk factors for complications.

Cardiac magnetic resonance based evaluation of aortic stiffness and epicardial fat volume in patients with hypertension, diabetes mellitus, and myocardial infarction

Background Aortic stiffness and epicardial fat relate to cardiovascular risk. Their relationship with each other and their role with hypertension, diabetes mellitus (DM), and myocardial infarction (MI) can be evaluated by cardiac magnetic resonance (CMR). Purpose To explore an association between aortic stiffness and epicardial as well as paracardial fat volume (EFV and ParaFV, respectively) in hypertensive patients and to relate the results to the presence of DM and MI. Material and Methods A total of 156 hypertensive and 20 non-hypertensive participants were examined at 1.5 Tesla. A 2D-velocity-encoded sequence was acquired to assess aortic pulse wave velocity (PWV in m/s) as a measure of aortic stiffness. A 3D-Dixon sequence was used to determine EFV and ParaFV. Results PWV correlated with EFV (Ru2009=u20090.474; Pu2009<u20090.001), but not with ParaFV. Fat volumes (in mL/m2) and PWV were lower in non-hypertensive controls compared to hypertensive patients. EFV and PWV were significantly higher in diabetic hypertensive patients without MI (nu2009=u200919; PWV: 10.4u2009±u20092.9; EFV: 92.5u2009±u200919.3) compared to hypertension-only patients (nu2009=u200984 [no DM or MI]; EFV: 64.8u2009±u200925.1, PWV: 9.0u2009±u20092.6; Pu2009<u20090.05). Logistic regression analysis showed a significant association between the presence of a MI and a higher EFV (Pu2009<u20090.05), but not with PWV (Pu2009=u20090.060) or ParaFV (Pu2009=u20090.375). Conclusion A relationship between aortic stiffness and EFV was found in hypertensive patients. Both were increased in the presence of DM; however, only EFV was increased in the presence of MI. This may relate to the PWV lowering effect of the antihypertensive medication used by hypertensive patients and underscores the benefit of EFV assessment in this regard.

Quantitative and Qualitative Assessment of Pulmonary Emphysema with T2-Weighted PROPELLER MRI in a High-Risk Population Compared to Low-Dose CT

PURPOSEnTo determine the suitability of T2-weighted PROPELLER MRI for the assessment of pulmonary emphysema.nnnMATERIALS AND METHODSn60 participants in a lung cancer screening program (30 subjects with pulmonary emphysema, and 30 control subjects without emphysema) were included for this retrospective study. All subjects were examined with low-dose CT (LDCT) and MRI within the screening program. The use of a T2-weighted PROPELLER sequence for the assessment of emphysema was analyzed and correlated with the results of LDCT. The presence and the extent of pulmonary emphysema were first assessed qualitatively using a three-point score, and then quantitatively with a semi-automated software program to obtain emphysema indices.nnnRESULTSnAll 30 cases with pulmonary emphysema were accurately detected by MRI. There were 3 cases with emphysema according to MRI without emphysematous changes on LDCT (false-positive results). The qualitative scores as well as the emphysema indices were significantly higher in the emphysema group compared to the control group for MRI and LDCT (pu200a<u200a0.001). Both the scores and the indices correlated significantly between MRI and LDCT (qualitative score of severity: ru200a=u200a0.912/pu200a<u200a0.001 in the emphysema group and ru200a=u200a0.668/pu200a<u200a0.001 in the control group; emphysema index: ru200a=u200a0.960/pu200a<u200a0.001 in the emphysema group and ru200a=u200a0.746/pu200a<u200a0.001 in the control group).nnnCONCLUSIONnThe presence and the extent of pulmonary emphysema may be assessed qualitatively and quantitatively by T2-weighted PROPELLER MRI with very good correlation to LDCT.nnnKEY POINTSn· T2-weighted PROPELLER MRI may be suitable for the assessment of pulmonary emphysema.. · There was significant correlation between MRI and LDCT regarding qualitative scores and quantitative emphysema indices in our study with correlation coefficients for different subgroups ranging from ru200a=u200a0.668 to ru200a=u200a0.960.. · T2-weighted PROPELLER MRI may have the potential to be used for follow-up examinations in patients with severe emphysema to avoid radiation exposure of repeated CTs..nnnCITATION FORMATn· Meier-Schroers M, Sprinkart AM, Becker M etu200aal. Quantitative and Qualitative Assessment of Pulmonary Emphysema with T2-Weighted PROPELLER MRI in a High-Risk Population Compared to Low-Dose CT. Fortschr Röntgenstr 2018; 190: 733u200a-u200a739.

Response to “Commentary on: Lung cancer screening with MRI: results of the first screening round”: Ngam Pei Ing et al.

Abbreviations DWI Diffusion-weighted imaging LDCT Low-dose computed tomography Lung-RADS Lung screening reporting and data system MVXD MultiVane XD (Philips Healthcare, Best, The Netherlands) SENSE Sensitivity encoding (Philips Healthcare, Best, The Netherlands) STIR Short tau inversion recovery Abstract Purpose To evaluate the suitability of MRI for lung cancer screening in a high-risk population. Materials and methods A 5-year lung cancer screening program comparing MRI and low-dose CT (LDCT) in a high-risk population was initiated. 224 subjects were examined with MRI and LDCT. Acquired MRI sequences were T2w MultiVane XD, balanced steady-state-free precession, 3D T1w GRE, and DWI with a maximum in-room-time of 20 min. Categorization and management of nodules were based on Lung-RADS. MRI findings were correlated with LDCT as a reference. Here, we report on the first screening round. Results MRI accurately detected 61 of 88 nodules 4–5 mm, 20 of 21 nodules 6–7 mm, 12 of 12 nodules 8–14 mm, 4 of 4 nodules ≥ 15 mm (solid nodules), and 8 of 11 subsolid nodules. Sensitivity/specificity of MRI for nodule detection was 69.3/96.4% for 4–5 mm, 95.2/99.6% for 6–7 mm, 100/99.6% for 8–14 mm, 100/100% for ≥ 15 mm (solid nodules), and 72.7/99.2% for subsolid nodules. The early recall rate was 13.8% for MRI and 12.5% for LDCT. Following LungRADS recommendations and based on interdisciplinary

Lung cancer screening with MRI: Evaluation of MRI for lung cancer screening by comparison of LDCT- and MRI-derived Lung-RADS categories in the first two screening rounds

PurposeTo evaluate MRI for lung cancer screening comparing LDCT- and MRI-derived Lung-RADS categories in the first two screening rounds.Materials and methods224 participants in a lung cancer screening study were examined with MRI and low-dose CT (LDCT). Acquired MRI sequences were T2, balanced, T1 and DWI. MRI was prospectively analysed regarding nodules. Minimum nodule size was 4 mm. Nodules were assigned a Lung-RADS score based on appearance and size at baseline and after 3, 6 and 12 months. MRI findings were correlated with LDCT.ResultsThe early recall rate dropped from 13.8% at baseline to 1.9% in the second screening round with biopsy rates of 3.6% in the first round and 0.5% in the second round. Histology revealed lung cancer in 8/9 participants undergoing biopsy/surgery. All eight cancers were accurately depicted by MRI. The following categories were assigned on MRI (results of LDCT in parentheses): 4B/4X in 10 (10) cases, 4A in 16 (15) cases, 3 in 13 (12) cases, 2 in 77 (92) cases and 1 in 140 (126) cases. Lung-RADS scoring correlated significantly between MRI and CT. The score was overestimated by MRI in one case for category 4A, in two cases for category 3 and in five cases for category 2. MRI-based Lung-RADS score was underestimated for category 1 in 20 cases.ConclusionLung-RADS might be applied for lung cancer screening with MRI, since findings correlated with LDCT. Relevant findings with a Lung-RADS score of 3 and higher were never missed or underestimated by MRIKey Points• MRI performed comparably to low-dose CT in a lung cancer-screening programme.• Lung-RADS might be applied for lung cancer screening with MRI.• Lung-RADS findings score of 3 and higher were never missed by MRI.

Lung cancer screening with MRI: characterization of nodules with different non-enhanced MRI sequences:

Background There is increased interest in pulmonary magnetic resonance imaging (MRI) as a radiation-free alternative to computed tomography (CT) for lung cancer screening. Purpose To analyze MRI characteristics of pulmonary nodules with different non-enhanced sequences. Material and Methods Eighty-two participants of a lung cancer screening were included. MRI datasets of 32 individuals with 46 different nodulesu2009≥u20096u2009mm were prospectively evaluated together with 50 controls by two readers. Acquired sequences were T2- short tau inversion recovery (STIR), T2, balanced steady-state free precession (bSSFP), 3D-T1, and diffusion-weighted imaging (DWI). Each sequence was randomly and separately viewed blinded to low-dose CT (LDCT). Size, shape, and contrast of nodules were evaluated on each sequence and then correlated with LDCT and histopathology. Results All eight carcinomas were detected by T2-STIR, T2, and bSSFP, and 7/8 by 3D-T1. Contrast was significantly higher for malignant nodules on all sequences. The highest contrast ratio between malignant and benign nodules was provided by T2-STIR. Of eight carcinomas, seven showed restricted diffusion. Size measurement correlated significantly between MRI and LDCT. Sensitivity/specificity for nodulesu2009≥u20096u2009mm was 85–89%/92–94% for T2-STIR, 80–87%/93–96% for T2, 65–70%/96–98% for bSSFP, and 63–67%/96–100% for 3D-T1. Seven of eight subsolid nodules were visible on T2-sequences with significantly lower lesion contrast compared to solid nodules. Two of eight subsolid nodules were detected by bSFFP, none by 3D-T1. All three calcified nodules were detected by 3D-T1, one by bSSFP, and none by T2-sequences. Conclusion Malignant as well as calcified and subsolid nodules seem to have distinctive characteristics on different MRI sequences. T2-imaging was most suitable for the detection of nodulesu2009≥u20096u2009mm.

Interrelations of Epicardial Fat Volume, Left Ventricular T1-Relaxation Times and Myocardial Strain in Hypertensive Patients: A Cardiac Magnetic Resonance Study

Purpose: This cardiac magnetic resonance study was performed to assess myocardial fibrosis by evaluating T1-relaxation time (T1), to measure left ventricular (LV) strain, and to determine epicardial fat volume (EFV) in hypertensive patients with no history of cardiovascular (CV) events and to relate the results to the presence of coronary atherosclerotic artery disease (CAD) in these patients. Materials and Methods: A total of 123 subjects were examined at 1.5 T. Of them, 98 were hypertensive patients (58 men; mean age, 62.9±10.7 y; body mass index, 29.0±5.6 kg/m2) and 25 were controls without CV risk factors or disease (13 men; 60.1±10.7 y; 28.1±5.4 kg/m2). All patients had a well-treated blood pressure. In the hypertensive group, 56 patients had no CAD, whereas 42 patients had CAD. T1 was assessed by a modified Look-Locker inversion recovery sequence. Longitudinal and circumferential peak systolic strain (LS; CS) was determined with dedicated cardiac magnetic resonance software (feature tracking). EFV (normalized to the body surface area) was assessed by a 3D Dixon sequence. Results: T1 (ms) and EFV (mL/m2) were higher and CS and LS (%) were lower in hypertensive patients compared with those in nonhypertensive controls (P<0.05), independent of the presence of CAD (controls: T1=967.2±16.9, LS=−25.2±4.6, CS=−28.7±5.0, EFV=58.2±21.1; hypertensive patients overall: T1=991.3±45.5, LS=−21.0±4.5, CS=−25.0±5.9, EFV=71.1±25.3; hypertensive patients without CAD: T1=991.6±48.4, LS=−21.0±4.7, CS=−24.6±6.3, EFV=71.3±26.6; hypertensive patients with CAD: T1=986.7±39.2, LS=−21.1±4.3, CS=−25.5±5.4, EFV=70.9±23.6). There were no significant differences between hypertensive patients with and those without CAD and between patients grouped according to the number of vessels affected (0-vessel disease, 1-vessel disease, 2-vessel disease, or 3-vessel disease). Conclusions: Hypertension is associated with signs of myocardial fibrosis and an impaired LV contractility despite a normal LV ejection fraction, as well as with an increased EFV. However, CAD, in the absence of previous pathologies with consecutive myocardial ischemic damage, did not additionally affect these parameters.