T2-weighted Single-shot Fast Spin-echo Research Articles

Implementation of a high-resolution, high-contrast magnetic resonance imaging protocol with extended delayed phases for peritoneal mesothelioma.

Imaging of peritoneal malignancies using conventional cross-sectional imaging is challenging, but accurate assessment of peritoneal disease burden could guide better selection for definitive surgery. Here we demonstrate feasibility of high-resolution, high-contrast magnetic resonance imaging (MRI) of peritoneal mesothelioma and explore optimal timing for delayed post-contrast imaging. Prospective data from inpatients with malignant peritoneal mesothelioma (MPM), imaged with a novel MRI protocol, were analyzed. The new sequences augmenting the clinical protocol were (I) pre-contrast coronal high-resolution T2-weighted single-shot fast spin echo (COR hr T2w SSH FSE) of abdomen and pelvis; and (II) post-contrast coronal high-resolution three-dimensional (3D) T1-weighted modified Dixon (COR hr T1w mDIXON) of abdomen, acquired at five delay times, up to 20 min after administration of a double dose of contrast agent. Quantitative analysis of contrast enhancement was performed using linear regression applied to normalized signal in lesion regions of interest (ROIs). Qualitative analysis was performed by three blinded radiologists. MRI exams from 14 participants (age: mean ± standard deviation, 60±12 years; 71% male) were analyzed. The rate of lesion contrast enhancement was strongly correlated with tumor grade (cumulative nuclear score) (r=-0.65, P<0.02), with 'early' delayed phase (12 min post-contrast) and 'late' delayed phase (19 min post-contrast) performing better for higher grade and lower grade tumors, respectively, in agreement with qualitative scoring of image contrast. High-resolution, high-contrast MRI with extended post-contrast imaging is a viable modality for imaging peritoneal mesothelioma. Multiple, extended (up to 20 min post-contrast) delayed phases are necessary for optimal imaging of peritoneal mesothelioma, depending on the grade of disease.

MRI AND BLOOD-BASED BIOMARKERS ASSOCIATED WITH SURGICAL MANAGEMENT IN CHILDREN AND ADULTS WITH SMALL BOWEL CROHN'S DISEASE

Abstract BACKGROUND Despite advances in medical therapy, many children and adults with ileal Crohn’s Disease (CD) progress to fibrostenosis requiring surgery. Prior studies have identified circulating and imaging biomarkers associated with strictures, although their associations with need for surgery are not well-established. PURPOSE We aimed to identify MRI and circulating biomarkers associated with the need for surgical management in chidlren and adults with ileal CD. METHODS This prospective, multi-center study included pediatric and adult CD cases undergoing ileal resection (n=50), and CD controls receiving medical therapy (n=83). Noncontrast research MRI examinations measured bowel wall three-dimensional magnetization transfer ratio normalized to skeletal muscle (normalized 3D MTR), modified Look-Locker inversion recovery (MOLLI) T1 relaxation, intravoxel incoherent motion (IVIM) diffusion-weighted imaging metrics, and the simplified magnetic resonance index of activity (sMaRIA) (Figure 1). Circulating biomarkers included CD64, ECM1, and GM-CSF autoantibodies (Ab). Clinical variables, including demographics, anthropometrics, and routine clinical laboratory data (e.g., CRP, fecal calprotectin), also were obtained at the research visit. Associations between MRI and circulating biomarkers and need for ileal resection were tested using univariate and multivariable LASSO regression. RESULTS Mean participant age was 23.9±13.1 years. Disease duration and treatment exposures did not vary between the groups. Univariate biomarker associations with ileal resection included log GM-CSF Ab (odds ratio [OR]=2.87; p=0.0009), normalized 3D MTR (OR=1.05; p=0.002), log MOLLI T1 (OR=0.01; p=0.02), log IVIM perfusion fraction (f) (OR=0.38; p=0.04), and IVIM apparent diffusion coefficient (ADC) (OR=0.3; p=0.001). MRI and circulating biomarker Tukey box plots are presented in Figure 2. The multivariable model for surgery based upon AICc criteria included age (OR=1.03; p=0.29), BMI (OR=0.91; p=0.09), log GM-CSF Ab (OR=3.37; p=0.01), normalized 3D MTR (OR=1.07; p=0.007), sMaRIA (OR=1.14; p=0.61), luminal narrowing (OR=10.19; p=0.003), log CRP (normalized) (OR=2.75; p=0.10), and hematocrit (OR=0.90; p=0.13). CONCLUSION After accounting for clinical and MRI measures of severity, normalized 3D MTR and GM-CSF Ab are associated with need for surgery in ileal CD. GM-CSF autoantibodies and MRI biomarker sequences may be useful for guiding management decisions in CD patients. Figure 1 Research MRI images from a surgical Crohn’s disease patient with stricturing behavior involving the terminal ileum. A and B. Coronal and axial fat-saturated T2-weighted single-shot fast spin-echo (SSFSE) images show wall thickening and luminal narrowing of the terminal ileum (arrows) with more proximal bowel dilation measuring greater than 3 cm. C. Axial 3D magnetization transfer images – MT pulse on (bottom image, arrow), MT pulse off (top image, arrow). D. Axial modified Look-Locker inversion recovery (MOLLI) T1 relaxation image (arrow). E. Representative axial intravoxel incoherent motion diffusion-weighted images with increasing b-values (left to right, arrows). Figure 2 Variation in circulating and imaging biomarkers in Crohn’s disease patients with medical and surgical management. Ctrl: non-IBD healthy controls; Med: CD patients with nonsurgical medical management; Surg: CD patients with surgical management.

Estimate of fetal brain temperature using proton resonance frequency thermometry during 3 Tesla fetal magnetic resonance imaging.

T2-weighted Single Shot Fast Spin Echo (SSFSE) scans at 3 Tesla (3T) are increasingly used to image fetal pathology due to their excellent tissue contrast resolution and signal-to-noise ratio (SNR). Temperature changes that may occur in response to radio frequency (RF) pulses used for these sequences at 3T have not been studied in human fetal brains. To evaluate the safety of T2-weighted SSFSE for fetal brains at 3T, magnetic resonance (MR) thermometry was used to measure relative temperature changes in a typical clinical fetal brain MR exam. Relative temperature was estimated using sets of gradient recalled echo (GRE) images acquired before and after T2-weighted SSFSE images which lasted 27.47±8.19 minutes. Thirty-one fetuses with cardiac abnormalities, and 20 healthy controls were included in this study. Fetal brain temperature was estimated by proton resonance frequency (PRF) thermometry and compared to the estimated temperature in the gluteal muscle of the mother. Seven scans with excessive motion were excluded. Local outlier factor (LOF) was performed to remove 12 additional scans with spurious phase measurements due to motion degradation and potential field drift. Linear regression was performed to determine if temperature changes are dependent on the rate of energy deposition during the scan. For the 32 participants used in the analysis, 17 with cardiac abnormalities and 15 healthy controls, the average relative fetal temperate change was 0.19±0.73 ℃ higher than the mother, with no correlation between relative temperature change and the rate of images acquired during the scans (regression coefficient =-0.05, R-squared =0.05, P=0.22, F-statistic =1.60). The difference in the relative temperature changes between the fetal brain and mother's gluteal tissue in the healthy controls was on average 0.08 ℃ lower and found not to be statistically different (P=0.76) to the group with cardiac abnormalities. Our results indicate that the estimated relative temperature changes of the fetal brain compared to the mother's gluteal tissue from RF pulses during the course of the T2-weighted SSFSE fetal MR exam are minimal. The differences in acquired phase between these regions through the exam were found not to be statistically different. These findings support that fetal brain imaging at 3T is within FDA limits and safe.

Magnetresonanz-Enterographie/Enteroklysma

Magnetic resonance enterography/enteroclysma (MRE) is an examination technique without ionizing radiation that allows assessment of bowel wall changes and extraluminal pathologies/complications such as in chronic inflammatory bowel diseases, among others. To discuss requirements for optimal MR imaging of the small bowel, technical basis of MRE and principles for the development and optimization of aMRE protocol, and clinical indications for this specific imaging technique. Guidelines, basic and review papers will be analyzed. MRE enables the diagnosis of inflammatory bowel diseases and neoplasms and their evaluation during therapy. In addition to intra- and transmural changes, extramural pathologies and complications can also be detected. Standard sequences include steady-state free precession sequences, T2-weighted single-shot fast spin echo sequences, and three-dimensional (3D) T1-weighted gradient echo (GRE) sequences with fat saturation after contrast administration. Prior to image acquisition, optimal patient preparation and distension of the bowel using intraluminal contrast agents is necessary. Careful patient preparation for MRE, understanding of optimal imaging technique, and appropriate clinical indications are essential to achieve high-quality images of the bowel for accurate assessment and diagnosis as well as therapy monitoring of small bowel disease.

High-Resolution Single-Shot Fast Spin-Echo MR Imaging with Deep Learning Reconstruction Algorithm Can Improve Repeatability and Reproducibility of Follicle Counting.

To investigate the diagnostic performance of high-resolution single-shot fast spin-echo (SSFSE) imaging with deep learning (DL) reconstruction algorithm on follicle counting and compare it with original SSFSE images and conventional fast spin-echo (FSE) images. This study included 20 participants (40 ovaries) with clinically confirmed polycystic ovary syndrome (PCOS) who underwent high-resolution ovary MRI, including three-plane T2-weighted FSE sequences and slice-matched T2-weighted SSFSE sequences. A DL reconstruction algorithm was applied to the SSFSE sequences to generate SSFSE-DL images, and the original SSFSE images were also saved. Subjective evaluations such as the blurring artifacts, subjective noise, and clarity of the follicles on the SSFSE-DL, SSFSE, and conventional FSE images were independently conducted by two observers. Intra-class correlation coefficients and Bland-Altman plots were used to present the repeatability and reproducibility of the follicle number per ovary (FNPO) based on the three types of images. SSFSE-DL images showed less blurring artifact, subjective noise, and better clarity of the follicles than SSFSE and FSE (p < 0.05). For the repeatability of the FNPO, SSFSE-DL showed the highest intra-observer (ICC = 0.930; 95% CI: 0.878-0.962) and inter-observer (ICC = 0.914; 95% CI: 0.843-0.953) agreements. The inter-observer 95% limits of agreement (LOA) for SSFSE-DL, SSFSE, and FSE ranged from -3.7 to 4.5, -4.4 to 7.0, and -7.1 to 7.6, respectively. The intra-observer 95% LOA for SSFSE-DL, SSFSE, and FSE ranged from -3.5 to 4.0, -5.1 to 6.1, and -5.7 to 4.2, respectively. The absolute values of intra-observer and inter-observer differences for SSFSE-DL were significantly lower than those for SSFSE and FSE (p < 0.05). Compared with the original SSFSE images and the conventional FSE images, high-resolution SSFSE images with DL reconstruction algorithm can better display follicles, thus improving FNPO assessment.

Effect of Averaging Measurements From Multiple MRI Pulse Sequences on Kidney Volume Reproducibility in Autosomal Dominant Polycystic Kidney Disease.

Total kidney volume (TKV) is an important biomarker for assessing kidney function, especially for autosomal dominant polycystic kidney disease (ADPKD). However, TKV measurements from a single MRI pulse sequence have limited reproducibility, ± ~5%, similar to ADPKD annual kidney growth rates. To improve TKV measurement reproducibility on MRI by extending artificial intelligence algorithms to automatically segment kidneys on T1-weighted, T2-weighted, and steady state free precession (SSFP) sequences in axial and coronal planes and averaging measurements. Retrospective training, prospective testing. Three hundred ninety-seven patients (356 with ADPKD, 41 without), 75% for training and 25% for validation, 40 ADPKD patients for testing and 17 ADPKD patients for assessing reproducibility. T2-weighted single-shot fast spin echo (T2), SSFP, and T1-weighted 3D spoiled gradient echo (T1) at 1.5 and 3T. 2D U-net segmentation algorithm was trained on images from all sequences. Five observers independently measured each kidney volume manually on axial T2 and using model-assisted segmentations on all sequences and image plane orientations for two MRI exams in two sessions separated by 1-3 weeks to assess reproducibility. Manual and model-assisted segmentation times were recorded. Bland-Altman, Schapiro-Wilk (normality assessment), Pearson's chi-squared (categorical variables); Dice similarity coefficient, interclass correlation coefficient, and concordance correlation coefficient for analyzing TKV reproducibility. P-value < 0.05 was considered statistically significant. In 17 ADPKD subjects, model-assisted segmentations of axial T2 images were significantly faster than manual segmentations (2:49 minute vs. 11:34 minute), with no significant absolute percent difference in TKV (5.9% vs. 5.3%, P=0.88) between scans 1 and 2. Absolute percent differences between the two scans for model-assisted segmentations on other sequences were 5.5% (axial T1), 4.5% (axial SSFP), 4.1% (coronal SSFP), and 3.2% (coronal T2). Averaging measurements from all five model-assisted segmentations significantly reduced absolute percent difference to 2.5%, further improving to 2.1% after excluding an outlier. Measuring TKV on multiple MRI pulse sequences in coronal and axial planes is practical with deep learning model-assisted segmentations and can improve TKV measurement reproducibility more than 2-fold in ADPKD. 2 TECHNICAL EFFICACY: Stage 1.

Semi-automatic segmentation of the fetal brain from magnetic resonance imaging.

Volumetric measurements of fetal brain maturation in the third trimester of pregnancy are key predictors of developmental outcomes. Improved understanding of fetal brain development trajectories may aid in identifying and clinically managing at-risk fetuses. Currently, fetal brain structures in magnetic resonance images (MRI) are often manually segmented, which requires both time and expertise. To facilitate the targeting and measurement of brain structures in the fetus, we compared the results of five segmentation methods applied to fetal brain MRI data to gold-standard manual tracings. Adult women with singleton pregnancies (n = 21), of whom five were scanned twice, approximately 3 weeks apart, were recruited [26 total datasets, median gestational age (GA) = 34.8, IQR = 30.9-36.6]. T2-weighted single-shot fast spin echo images of the fetal brain were acquired on 1.5T and 3T MRI scanners. Images were first combined into a single 3D anatomical volume. Next, a trained tracer manually segmented the thalamus, cerebellum, and total cerebral volumes. The manual segmentations were compared with five automatic methods of segmentation available within Advanced Normalization Tools (ANTs) and FMRIB's Linear Image Registration Tool (FLIRT) toolboxes. The manual and automatic labels were compared using Dice similarity coefficients (DSCs). The DSC values were compared using Friedman's test for repeated measures. Comparing cerebellum and thalamus masks against the manually segmented masks, the median DSC values for ANTs and FLIRT were 0.72 [interquartile range (IQR) = 0.6-0.8] and 0.54 (IQR = 0.4-0.6), respectively. A Friedman's test indicated that the ANTs registration methods, primarily nonlinear methods, performed better than FLIRT (p < 0.001). Deformable registration methods provided the most accurate results relative to manual segmentation. Overall, this semi-automatic subcortical segmentation method provides reliable performance to segment subcortical volumes in fetal MR images. This method reduces the costs of manual segmentation, facilitating the measurement of typical and atypical fetal brain development.

Impact of adaptive image receive coil technology for liver MR imaging at 3.0 Tesla: Intraindividual comparison with use of conventional coil

PurposeA newly developed Adaptive Image Receive (AIR) coil is designed to be more flexible to conform to the human body habitus, and may improve image quality by reducing the distance between the coil element and the imaging subject. This study evaluated the AIR coil's usefulness for liver MR imaging at 3.0 T in comparison with that of a conventional coil retrospectively. MethodThe study population comprised 50 consecutive patients, who underwent follow-up liver MR examinations with a 3.0-T MR system using both an AIR coil and a conventional coil to evaluate hepatocellular carcinoma. Three-dimensional fat-suppressed T1-weighted gradient-echo images before and after injection of an MRI contrast agent, T2-weighted single-shot fast spin-echo (SSFSE) images, and diffusion-weighted (DW) images obtained with the AIR coil were compared with corresponding images obtained with the conventional coil. One radiologist measured signal-to-noise ratios (SNRs), while two other radiologists used a 3-point scale to independently assess subjective image noise, artifacts, signal uniformity, and overall image quality. ResultsSNRs for the AIR coil were significantly higher than those for the conventional coil (P <.05). Subjective image noise for the AIR coil on pre- and postcontrast T1-weighted and DW images was lower than for the conventional coil for both readers (P <.05). Overall image quality on pre- and postcontrast T1-weighted and DW images for the AIR coil was better than that for the conventional coil for at least one reader (P <.05). ConclusionsIn comparison with the conventional coil, AIR coil improved SNR and image quality of liver MR imaging.

Free-breathing magnetic resonance imaging with radial k-space sampling for neonates and infants to reduce anesthesia.

Conventional chest and abdominal MRI require breath-holds to reduce motion artifacts. Neonates and infants require general anesthesia with intubation to enable breath-held acquisitions. We aimed to validate a free-breathing approach to reduce general anesthesia using a motion-insensitive radial acquisition with respiratory gating. We retrospectively enrolled children <3years old who were referred for MRI of the chest or abdomen. They were divided into two groups according to MRI protocol: (1) breath-held scans under general anesthesia with T2-weighted single-shot fast spin-echo (SSFSE) and contrast-enhanced T1-weighted modified Dixon, and (2) free-breathing scans using radial sequences (T2-W MultiVane XD and contrast-enhanced T1-W three-dimensional [3-D] Vane XD). Two readers graded image quality and motion artifacts. We included 23 studies in the free-breathing cohort and 22 in the breath-hold cohort. The overall imaging scores for the free-breathing radial T2-W sequence were similar to the scores for the breath-held T2-W SSFSE sequence (chest, 3.6 vs. 3.2, P=0.07; abdomen, 3.9 vs. 3.7, P=0.66). The free-breathing 3-D radial T1-W sequence also had image quality scores that were similar to the breath-held T1-W sequence (chest, 4.0 vs. 3.0, P=0.06; abdomen, 3.7 vs. 3.9, P=0.15). Increased motion was seen in the abdomen on the radial T2-W sequence (P<0.001), but increased motion was not different in the chest (P=0.73) or in contrast-enhanced T1-W sequences (chest, P=0.39; abdomen, P=0.15). The mean total sequence time was longer in free-breathing compared to breath-held exams (P<0.01); however, this did not translate to longer overall exam times (P=0.94). Motion-insensitive radial sequences used for infants and neonates were of similar image quality to breath-held sequences and had decreased sedation and intubation.

MRI-based kidney radiomic analysis during chronic lithium treatment.

Lithium therapy during bipolar disorder is associated with an increased risk of chronic kidney disease (CKD) that is slowly progressive and undetectable at early stages. We aimed at identifying kidney image texture features as possible imaging biomarkers of decreased measured glomerular filtration rate (mGFR) using radiomics of T2-weighted magnetic resonance imaging (MRI). One hundred and eight patients treated with lithium were evaluated including mGFR and kidney MRI, with T2-weighted sequence single-shot fast spin-echo. Computed radiomic analysis was performed after kidney segmentation. Significant features were selected to build a radiomic signature using multivariable Cox analysis to detect an mGFR <60ml/min/1.73m². The texture index was validated using a training and a validation cohort. Texture analysis index was able to detect an mGFR decrease, with an AUC of 0.85 in the training cohort and 0.71 in the validation cohort. Patients with a texture index below the median were older (59 [42-66] vs. 46 [34-54] years, p=.001), with longer treatment duration (10 [3-22] vs. 6 [2-10] years, p=.02) and a lower mGFR (66 [46-84] vs. 83 [71-94] ml/min/1.73m², p<.001). Texture analysis index was independently and negatively associated with age (β=-.004±0.001, p<.001), serum vasopressin (-0.005±0.002, p=.02) and lithium treatment duration (-0.01±0.003, p=.001), with a significant interaction between lithium treatment duration and mGFR (p=.02). A renal texture index was developed among patients treated with lithium associated with a decreased mGFR. This index might be relevant in the diagnosis of lithium-induced renal toxicity.

Characterizing Fibrosis and Inflammation in a Partial Bile Duct Ligation Mouse Model by Multiparametric Magnetic Resonance Imaging

BackgroundPartial bile duct ligation (PBDL) model is a reliable cholestatic fibrosis experimental model that showed complex histopathological changes. Magnetic resonance imaging (MRI) features of PBDL have not been well characterized.PurposeTo investigate the potential of MRI parameters in assessing fibrosis in PBDL and explore the relationships between MRI and pathological features.Animal ModelEstablished PBDL models.PopulationFifty‐four mice were randomly divided into four timepoints PBDL groups and one sham group.Field Strength/Sequence3.0 T; MRI sequences included T1‐weighted fast spin‐echo (FSE), T2‐weighted single shot FSE, variable flip angle T1 mapping, multi‐echo SE T2 mapping, multi‐echo gradient‐echo T2* mapping, and multi‐b‐value diffusion‐weighted imaging.AssessmentMRI examination was performed at the corresponding timepoints after surgery. Native T1, ΔT1 (T1native‐T1post), T2, T2*, apparent diffusion coefficient (ADC) values, histogram parameters (skewness and kurtosis), intravoxel incoherent motion parameters (f, D, and D *) within the entire ligated (PBDL), non‐ligated liver (PBDL), and whole liver (sham) were obtained. Fibrosis and inflammation were assessed in Masson and H&E staining slices using the Metavir and activity scoring system.Statistical TestsOne‐way ANOVA, Spearman's rank correlation, and receiver operating characteristic curves were performed. P < 0.05 was considered statistically significant.ResultsFibrosis and inflammation were finally staged as F3 and A3 in ligated livers but were not observed in non‐ligated or sham livers. Ligated livers displayed significantly elevated native T1, ΔT1, T2, and reduced ADC and T2* than other livers. Spearman's correlation showed better correlation with inflammation (r = 0.809) than fibrosis (r = 0.635) in T2 and both ΔT1 and ADC showed stronger correlation with fibrosis (r = 0.704 and r = −0.718) than inflammation (r = 0.564 and r = −0.550). Area under the curve (AUC) for ΔT1 performed the highest (0.896). When combined with all relative parameters, AUC increased to 0.956.Data ConclusionMultiparametric MRI can evaluate and differentiate pathological changes in PBDL. ΔT1 and ADC better correlated with fibrosis while T2 stronger with inflammation.Level of Evidence1Technical EfficacyStage 2

MRI signs of intrauterine fetal demise.

Intrauterine fetal demise (IUFD) is an uncommon but serious event that may occasionally be encountered on fetal MRI. Compared to the more florid signs of fetal demise which has occurred some time ago, recent IUFD is associated with more subtle findings that may be missed or misinterpreted. The two main MRI sequences used in imaging the fetus are T2-like two-dimensional balanced steady-state free-precession (SSFP), a white blood sequence, or T2-weighted single-shot fast spin-echo (SSFSE), a black blood sequence. The most reliable and specific signs of a recent IUFD are a constricted heart with poorly delineated cardiac chambers and signal abnormality in the heart and aorta, which will have different features depending on the MRI sequence used. Secondary signs of IUFD include global brain ischemia, abnormal globes, effusions, body wall edema and umbilical cord thrombosis. Unlike fetal ultrasound examinations where cardiac activity is routinely assessed, fetal MRI requires careful scrutiny of the fetal heart for assessment of fetal life.

Fetal growth, fetal development, and placental features in women with polycystic ovary syndrome: analysis based on fetal and placental magnetic resonance imaging.

Polycystic ovary syndrome (PCOS), a common endocrine-metabolic dysfunction in reproductive-aged women, may be involved in compromised pregnancy and offspring outcomes. This study aimed to investigate whether maternal PCOS affects fetal growth, fetal development, and placental features. This retrospective case-control study included 60 pregnant women with PCOS (PCOS group) and 120 healthy pregnant women without PCOS (control group). Fetal magnetic resonance imaging (MRI) was performed followed by an ultrasound examination and indications for imaging, including known or suspected fetal pathology, history of fetal abnormality in previous pregnancy or in a family member, and concern for placenta accreta. Fetal MRI images were analyzed for head circumference (HC), abdomen circumference (AC), lung-to-liver signal intensity ratio (LLSIR, a prenatal marker of fetal lung maturity), lengths of liver and kidney diameters in fetuses, and placental relative signal intensity on T2-weighted single-shot fast spin echo (SSFSE) imaging (rSISSFSE), and placental relative apparent diffusion coefficient value (rADC). Data on height and weight of offspring were collected through telephone follow-up. Compared to the control group, the PCOS group showed the following characteristics: (1) smaller biparietal diameter and femur length in fetuses (P=0.026 and P=0.005, respectively), (2) smaller HC in fetuses (evident after 32 weeks; P=0.044), (3) lower LLSIR and smaller dorsoventral length of liver in fetuses (evident before 32 weeks; P=0.005 and P=0.019, respectively), and (4) smaller placental thickness (evident before 32 weeks; P=0.017). No significant differences in placental rSISSFSE or rADC were observed between the groups (all P>0.05). No significant differences in height and weight of offspring during childhood existed between the groups (all P>0.05). There exist alterations of fetal growth, fetal development, and placental features from women with PCOS.

Enhancing the differentiation of pulmonary lymphoma and fungal pneumonia in hematological patients using texture analysis in 3-T MRI

ObjectivesTo evaluate texture analysis in nonenhanced 3-T MRI for differentiating pulmonary fungal infiltrates and lymphoma manifestations in hematological patients and to compare the diagnostic performance with that of signal intensity quotients (“nonenhanced imaging characterization quotients,” NICQs).MethodsMR scans were performed using a speed-optimized imaging protocol without an intravenous contrast medium including axial T2-weighted (T2w) single-shot fast spin-echo and T1-weighted (T1w) gradient-echo sequences. ROIs were drawn within the lesions to extract first-order statistics from original images using HeterogeneityCAD and PyRadiomics. NICQs were calculated using signal intensities of the lesions, muscle, and fat. The standard of reference was histology or clinical diagnosis in follow-up. Statistical testing included ROC analysis, clustered ROC analysis, and DeLong test. Intra- and interrater reliability was tested using intraclass correlation coefficients (ICC).ResultsThirty-three fungal infiltrates in 16 patients and 38 pulmonary lymphoma manifestations in 19 patients were included. Considering the leading lesion in each patient, diagnostic performance was excellent for T1w entropy (AUC 80.2%; p < 0.005) and slightly inferior for T2w energy (79.9%; p < 0.005), T1w uniformity (79.6%; p < 0.005), and T1w energy (77.0%; p < 0.01); the best AUC for NICQs was 72.0% for T2NICQmean (p < 0.05). Intra- and interrater reliability was good to excellent (ICC > 0.81) for these parameters except for moderate intrarater reliability of T1w energy (ICC = 0.64).ConclusionsT1w entropy, uniformity, and energy and T2w energy showed the best performances for differentiating pulmonary lymphoma and fungal pneumonia and outperformed NICQs. Results of the texture analysis should be checked for their intrinsic consistency to identify possible incongruities of single parameters.Key Points• Texture analysis in nonenhanced pulmonary MRI improves the differentiation of pulmonary lymphoma and fungal pneumonia compared with signal intensity quotients.• T1w entropy, uniformity, and energy along with T2w energy show the best performances for differentiating pulmonary lymphoma from fungal pneumonia.• The results of the texture analysis should be checked for their intrinsic consistency to identify possible incongruities of single parameters.

Diagnostic Performance and Reliability of Non-Enhanced Imaging Characterization Quotients for the Differentiation of Infectious andMalignant Pulmonary Nodules in Hematological Patients Using 3T MRI.

To evaluate the diagnostic performance and reliability of non-enhanced imaging characterization quotients (NICQs) derived from magnetic resonance imaging (MRI) in the differential diagnosis of pulmonary nodules in hematological patients. A total of 83 lesions in 45 consecutive hematological patients were analyzed (10 bacterial pneumonias, 16 fungal pneumonias, 19 pulmonary lymphoma manifestations). The MRI protocol included T2-weighted single-shot fast spin echo (FSE) and T1-weighted gradient echo (GRE) sequences. T2-based T2-NICQmean and T2-NICQ90th were calculated from signal intensities measured in the lesion, muscle, and fat ((SILesion - SIMuscle)/(SIFat - SIMuscle) * 100), and simple T1-based T1-Qmean from signal intensities of the lesion and muscle (SILesion/SIMuscle). Images were read by one radiologist with > 7 years and one with 1year of experience. For statistical evaluation the Kruskal-Wallis or Mann-Whitney U-test, receiver operating characteristic (ROC) analysis with calculation of areas under the curve (AUC), and intraclass correlation coefficients (ICCs) were used. Medians of T2-NICQs differed significantly when comparing infectious lesions and lymphoma manifestations in general (T2-NICQmean 20.33 vs. 10.14; T2-NICQ90th 34.96 vs. 25.52) or fungal lesions and lymphoma manifestations in particular (T2-NICQmean 19.00 vs. 10.14; T2-NICQ90th 34.49 vs. 25.25). The AUCs for T2-NICQs on the per-patient level ranged from 0.73 to 0.79. ICCs were at least > 0.85, except for intrarater testing of T2-NICQ90th (0.79). The overall diagnostic performance of T2-NICQs is adequate for differentiating infectious and fungal lesions from lymphoma manifestations. The results show good to excellent intra- and interrater agreement. We therefore consider NICQs helpful in the diagnostic workup of pulmonary nodules in hematological patients. · Non-enhanced Imaging Characterization Quotients provide a fast and pragmatic approach for assessing pulmonary lesions in hematological patients.. · The diagnostic performance of Non-enhanced Imaging Characterization Quotients is adequate for differentiating infectious and fungal infiltrates from lymphoma manifestations.. · Non-enhanced Imaging Characterization Quotients show good to excellent intra- and interrater agreement.. · Nagel SN, Kim D, Wylutzki T et al. Diagnostic Performance and Reliability of Non-Enhanced Imaging Characterization Quotients for the Differentiation of Infectious and Malignant Pulmonary Nodules in Hematological Patients Using 3T MRI. Fortschr Röntgenstr 2020; 192: 327 - 334.

Echo-planar FLAIR Sequence Improves Subplate Visualization in Fetal MRI of the Brain.

Background The cortical plate (future cortex) is readily identifiable in utero at MRI. However, MRI evaluation of the remaining brain layers is limited by the poor T2 contrast between the subplate and the underlying intermediate zone (IZ). Purpose To compare the delineation of fetal brain lamination between T2-weighted single-shot fast spin-echo (SSFSE) and echo-planar imaging (EPI) fluid-attenuated inversion recovery (FLAIR) images, and to quantify differences in the depiction of brain layering between the two sequences. Materials and Methods Consecutive fetal brain MRI examinations performed between January 2014 and March 2018 with T2-weighted SSFSE and EPI-FLAIR images were reviewed. Two neuroradiologists evaluated the visibility of brain layers by using a three-point grading system, and findings were compared by using the sign test. One rater performed region-of-interest analysis in the cortical plate (CP), subplate (gyral crest and sulcal bottom), and IZ. Signal intensity (SI) ratios between adjacent brain compartments were calculated and compared by using the paired t test. Reader agreement was assessed by using weighted κ values. Results A total of 259 MRI examinations (mean gestational age [GA], 26.9 weeks ± 5.6) were included in the qualitative analysis, and 72 MRI examinations (mean GA, 27.4 weeks ± 5.5) were included in the quantitative analysis. Subplate identification on EPI-FLAIR images was superior to that on T2-weighted SSFSE images (subplate visualization [complete + partial]: frontal lobe, n = 243 vs n = 117; temporal lobe, n = 244 vs n = 137; parietal lobe n = 240 vs n = 93; and occipital lobe, n = 241 vs n = 97, respectively; P < .001), with higher interrater reliability (κ = 0.91-0.95 for EPI-FLAIR images and 0.80-0.87 for T2-weighted SSFSE images). SI ratios between the IZ and subplate were significantly higher on EPI-FLAIR images in all lobes (EPI-FLAIR images: 1.6-2.1; T2-weighted SSFSE images:1.2-1.2; P < .001). Subplate-to-CP ratios were not statistically significant between the two sequences (EPI-FLAIR:1.8-2.4; T2-weighted SSFSE: 2.0-2.2; P < .001). Conclusion The echo-planar fluid-attenuated inversion recovery sequence improves visualization of fetal brain lamination compared with the T2-weighted single-shot fast spin-echo sequence, as established by quantitative and qualitative methods. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Rossi in this issue.

Assessment of interobserver agreement and use of selected magnetic resonance imaging variables for differentiation of acute noncompressive nucleus pulposus extrusion and ischemic myelopathy in dogs.

OBJECTIVE To evaluate interobserver agreement for features used in presumptive diagnosis of acute noncompressive nucleus pulposus extrusion (ANNPE) or ischemic myelopathy by MRI, compare findings on postcontrast T1-weighted (T1W) MRI sequences with fat saturation (FS) for the 2 conditions, and determine whether length and directional patterns of hyperintensity of the intramedullary spinal cord on T2-weighted (T2W) fast spin echo (FSE) MRI sequences differ between dogs with these diseases. DESIGN Retrospective, observational study. ANIMALS 20 dogs with clinical signs compatible with ANNPE (n = 14) or ischemic myelopathy (6). PROCEDURES 3 observers evaluated MRI data (including T2W FSE, T2W single-shot FSE, and T1W FS sequences) for dogs with a presumptive diagnosis of ischemic myelopathy or ANNPE. Interobserver agreement for variables of interest including presumptive diagnosis was assessed by κ statistic calculations. Associations between diagnosis and variables of interest were assessed with Fisher exact or Cochran-Mantel-Haenszel tests. RESULTS Perfect interobserver agreement (κ = 1 for all comparisons) was found for the presumptive diagnosis of ischemic myelopathy versus ANNPE. Meningeal enhancement on postcontrast T1W FS MRI images and nonlongitudinal directional pattern of intramedullary hyperintensity on T2W FSE images were significantly associated with a diagnosis of ANNPE. Greater length of intramedullary hyperintensity was significantly associated with a diagnosis of ischemic myelopathy. CONCLUSIONS AND CLINICAL RELEVANCE Directional pattern and length of intramedullary hyperintensity on T2W FSE MRI images and enhancement patterns in postcontrast T1W FS sequences may provide important contributions to the criteria currently used in the presumptive diagnosis of ischemic myelopathy versus ANNPE.

Comparison of diffusion-weighted imaging and T2-weighted single shot fast spin-echo: Implications for LI-RADS characterization of hepatocellular carcinoma

PurposeTo evaluate the performance of diffusion-weighted imaging (DWI) and T2-weighted single shot fast spin-echo (SSFSE) imaging of the liver in the detection of hepatocellular carcinoma (HCC) in reference to the LI-RADS classification system. MethodsMR images of 40 patients with 68 LI-RADS grade 3–5 lesions were analyzed. Two readers independently reviewed sequences and characterized lesion signal intensity, followed by consensus evaluation. CE-MRI served as reference standard. Sensitivities were compared across sequences. Lesion-to-liver contrast-to-noise ratios (CNRs) and apparent diffusion coefficients (ADCs) were measured and compared using the Wilcoxon signed-rank test across sequences and the Mann–Whitney U or Kruskal–Wallis test between LI-RADS categories. Inter-reader variability was assessed using Cohen's kappa statistic. ResultsConsensus sensitivities of LI-RADS 3–5 lesions using SSFSE images versus DWI were similar (0.53–0.63, p=0.089), however, the sensitivity with DWI b=700 was higher (0.63) than DWI b=0 (0.53, p=0.039). Lesion-to-liver CNRs were larger for all DWI sequences compared to SSFSE images (p<0.001 for all). ADCs of large (>2cm) LIRADS 3–5 lesions were lower than those of small lesions (1.09±0.33 vs. 1.31±0.26, p=0.02), however lesion ADCs were not different from those of adjacent hepatic parenchyma for any LI-RADS lesion. ConclusionsDWI has a similar sensitivity compared to SSFSE, but intensity on DWI likely represents intrinsic T2 signal hyper-intensity rather than restricted diffusion as the ADC values were not lower than adjacent parenchyma. Therefore it may not be appropriate to consider hyper-intensity on high b-value as a separate ancillary criteria to T2 hyper-intensity in LI-RADS.

Diagnostic Per-Patient Accuracy of an Abbreviated Hepatobiliary Phase Gadoxetic Acid–Enhanced MRI for Hepatocellular Carcinoma Surveillance

OBJECTIVE. The purpose of this study is to evaluate the per-patient diagnostic performance of an abbreviated gadoxetic acid-enhanced MRI protocol for hepatocellular carcinoma (HCC) surveillance. MATERIALS AND METHODS. A retrospective review identified 298 consecutive patients at risk for HCC enrolled in a gadoxetic acid-enhanced MRI-based HCC surveillance program. For each patient, the first gadoxetic acid-enhanced MRI was analyzed. To simulate an abbreviated protocol, two readers independently read two image sets per patient: set 1 consisted of T1-weighted 20-minute hepatobiliary phase and T2-weighted single-shot fast spin-echo (SSFSE) images; set 2 included diffusion-weighted imaging (DWI) and images from set 1. Image sets were scored as positive or negative according to the presence of at least one nodule 10 mm or larger that met the predetermined criteria. Agreement was assessed using Cohen kappa statistics. A composite reference standard was used to determine the diagnostic performance of each image set for each reader. RESULTS. Interreader agreement was substantial for both image sets (κ = 0.72 for both) and intrareader agreement was excellent (κ = 0.97-0.99). Reader performance for image set 1 was sensitivity of 85.7% for reader A and 79.6% for reader B, specificity of 91.2% for reader A and 95.2% for reader B, and negative predictive value of 97.0% for reader A and 96.0% for reader B. Reader performance for image set 2 was nearly identical, with only one of 298 examinations scored differently on image set 2 compared with set 1. CONCLUSION. An abbreviated MRI protocol consisting of T2-weighted SSFSE and gadoxetic acid-enhanced hepatobiliary phase has high negative predictive value and may be an acceptable method for HCC surveillance. The inclusion of a DWI sequence did not significantly alter the diagnostic performance of the abbreviated protocol.

Retroperitoneal low-flow vascular malformations: characteristic MRI findings correlated with histopathological findings.

To evaluate the MRI findings of retroperitoneal low-flow vascular malformations (RLVMs) correlated with histopathological findings. Two radiologists reviewed the MRI findings of 4 RLVMs (3 with capillary malformations and 1 with a venous malformation). First, they evaluated the visibility, signal intensities, and signal homogeneity of each lesion on non-fat-suppressed breath-hold T2-weighted single-shot fast spin-echo (non-FS SSFSE) images and fat-suppressed T2-weighted fast spin-echo (FS T2-weighted FSE) images. Second, the kinetic patterns and the internal enhancement patterns were analyzed for each lesion on multi-phasic contrast-enhanced (CE) images. After these image analyses, the MRI findings were correlated with the histopathological findings. Histopathologically, the 4 RLVMs did not exhibit remarkable degeneration and were present in the retroperitoneal fat tissue without clear capsules. On the non-FS SSFSE images, 3 of the 4 RLVMs could not be discriminated from the surrounding retroperitoneal fat tissue (invisible), and the remaining lesion was barely visible with an indistinct margin. On the FS T2-weighted FSE images, however, all the RLVMs were clearly visualized as homogeneous high-signal intensities. On the multi-phasic CE images, all the capillary malformations exhibited fast enhancement, while a venous malformation showed slow enhancement. Furthermore, the RLVMs tended to exhibit a centripetal filling pattern. The RLVMs blended in with the surrounding retroperitoneal fat tissue on non-FS SSFSE images, like phantoms, whereas they were clearly visualized on FS T2-weighted FSE images. On multi-phasic CE images, the RLVMs tended to exhibit a centripetal filling pattern. These imaging features may be useful diagnostic clues for RLVMs.