Single-shot Turbo Spin-echo Imaging Research Articles

Correlation of fetal lung area with MRI derived pulmonary volume

BackgroundNeonatal chest-Xray (CXR)s are commonly performed as a first line investigation for the evaluation of respiratory complications. Although lung area derived from CXRs correlates well with functional assessments of the neonatal lung, it is not currently utilised in clinical practice, partly due to the lack of reference ranges for CXR-derived lung area in healthy neonates. Advanced MR techniques now enable direct evaluation of both fetal pulmonary volume and area. This study therefore aims to generate reference ranges for pulmonary volume and area in uncomplicated pregnancies, evaluate the correlation between prenatal pulmonary volume and area, as well as to assess the agreement between antenatal MRI-derived and neonatal CXR-derived pulmonary area in a cohort of fetuses that delivered shortly after the antenatal MRI investigation. MethodsFetal MRI datasets were retrospectively analysed from uncomplicated term pregnancies and a preterm cohort that delivered within 72 h of the fetal MRI. All examinations included T2 weighted single-shot turbo spin echo images in multiple planes. In-house pipelines were applied to correct for fetal motion using deformable slice-to-volume reconstruction. An MRI-derived lung area was manually segmented from the average intensity projection (AIP) images generated. Postnatal lung area in the preterm cohort was measured from neonatal CXRs within 24 h of delivery. Pearson correlation coefficient was used to correlate MRI-derived lung volume and area. A two-way absolute agreement was performed between the MRI-derived AIP lung area and CXR-derived lung area. ResultsDatasets from 180 controls and 10 preterm fetuses were suitable for analysis. Mean gestational age at MRI was 28.6 ± 4.2 weeks for controls and 28.7 ± 2.7 weeks for preterm neonates. MRI-derived lung area correlated strongly with lung volumes (p < 0.001). MRI-derived lung area had good agreement with the neonatal CXR-derived lung area in the preterm cohort [both lungs = 0.982]. ConclusionMRI-derived pulmonary area correlates well with absolute pulmonary volume and there is good correlation between MRI-derived pulmonary area and postnatal CXR-derived lung area when delivery occurs within a few days of the MRI examination. This may indicate that fetal MRI derived lung area may prove to be useful reference ranges for pulmonary areas derived from CXRs obtained in the perinatal period.

Feasibility of deep learning-reconstructed thin-slice single-breath-hold HASTE for detecting pancreatic lesions: A comparison with two conventional T2-weighted imaging sequences

ObjectiveThe objective of this study was to evaluate the clinical feasibility of deep learning reconstruction-accelerated thin-slice single-breath-hold half-Fourier single-shot turbo spin echo imaging (HASTEDL) for detecting pancreatic lesions, in comparison with two conventional T2-weighted imaging sequences: compressed-sensing HASTE (HASTECS) and BLADE. MethodsFrom March 2022 to January 2023, a total of 63 patients with suspected pancreatic-related disease underwent the HASTEDL, HASTECS, and BLADE sequences were enrolled in this retrospectively study. The acquisition time, the pancreatic lesion conspicuity (LCP), respiratory motion artifact (RMA), main pancreatic duct conspicuity (MPDC), overall image quality (OIQ), signal-to-noise ratio (SNR), and contrast-noise-ratio (CNR) of the pancreatic lesions were compared among the three sequences by two readers. ResultsThe acquisition time of both HASTEDL and HASTECS was 16 s, which was significantly shorter than that of 102 s for BLADE. In terms of qualitative parameters, Reader 1 and Reader 2 assigned significantly higher scores to the LCP, RMA, MPDC, and OIQ for HASTEDL compared to HASTECS and BLADE sequences; As for the quantitative parameters, the SNR values of the pancreatic head, body, tail, and lesions, the CNR of the pancreatic lesion measured by the two readers were also significantly higher for HASTEDL than for HASTECS and BLADE sequences. ConclusionsCompared to conventional T2WI sequences (HASTECS and BLADE), deep-learning reconstructed HASTE enables thin slice and single-breath-hold acquisition with clinical acceptable image quality for detection of pancreatic lesions.

PD01-05 PROBING THE BLADDER WALL DIFFUSION OF INSTILLED GADOBUTROL BY MRI

You have accessJournal of UrologyInfections/Inflammation/Cystic Disease of the Genitourinary Tract: Interstitial Cystitis (PD01)1 Sep 2021PD01-05 PROBING THE BLADDER WALL DIFFUSION OF INSTILLED GADOBUTROL BY MRI Pradeep Tyagi, Chan-Hong Moon, Nishant Singh, Marc Connell, Jodi Maranchie, Christopher Chermansky, Naoki Yoshimura, and Jonathan Kaufman Pradeep TyagiPradeep Tyagi More articles by this author , Chan-Hong MoonChan-Hong Moon More articles by this author , Nishant SinghNishant Singh More articles by this author , Marc ConnellMarc Connell More articles by this author , Jodi MaranchieJodi Maranchie More articles by this author , Christopher ChermanskyChristopher Chermansky More articles by this author , Naoki YoshimuraNaoki Yoshimura More articles by this author , and Jonathan KaufmanJonathan Kaufman More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000001965.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Intravesical therapy is critical for bladder cancer and a secondary option for interstitial cystitis and overactive bladder patient's refractory to oral treatment. Although paracellular diffusion of instilled drugs and radioactive agents from urine is suggested by ultrastructural studies and studies on diffusion across the excised whole bladder wall in Ussing chamber, the kinetics of diffusion across just the thickness of bladder mucosa is yet to be probed directly in a radiation-free manner with a non-invasive, non-tissue destructive method. Since MRI is capable of imaging the microscopic dimensions of bladder mucosa (Am J Physiol Renal Physiol 2020;319(3): F506-F514.), we investigated the diffusion kinetics of instilled Gadobutrol in a phantom constructed with 12% polyacrylamide (PLGA) gel, whose nanometer sized pores can partly mimic the nanometer gap of the apico-lateral tight junctions in mammalian urothelium. METHODS: PLGA gel was poured into a plastic jar while embedding 9 glass tubes which were removed upon setting of gel to create 9 cylindrical cavities for instilling ascending concentrations [0.5-20 mM] of Gadobutrol together with a fixed concentration of Ferumoxytol 0.1 mM. Phantom was wrapped by a 4 channel-flexible receiver coil for imaging in 3T scanner (Siemens, BioGraph) using T2 weighted Half-Fourier Acquisition Single-shot Turbo spin Echo imaging (HASTE) (repetition time 1000-1300 ms/echo time 80-90 ms). Gel diffusion of Gadobutrol was assessed by imaging at 30 min and at 5 h. RESULTS: The bright ring around the cavities demonstrates that molecular size of 0.8 nm permits easy diffusion of Gadobutrol into the >40 times bigger pores of 12% PLGA gel. The concentration gradient is the driving force for Gadobutrol diffusion is supported by the dependence of ring brightness on Gadobutrol concentration [0.5-20 mM] at room temperature and on the expansion of dark blob at 5 h in cavities filled with Gadobutrol 5-20 mM to recapitulate the classical pseudolayering effect of Gadobutrol accumulating into stored urine of bladder. CONCLUSIONS: MR imaging validated the linear relationship between Gadobutrol concentration in cavity and the signal gain in the surrounding gel, a surrogate for bladder mucosa. Findings support that MRI at clinical scanner can reliably assess the mucosal diffusion of instilled drugs and probes in bladder permeability assay. Source of Funding: DK 108397;CA252590 © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e32-e32 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Pradeep Tyagi More articles by this author Chan-Hong Moon More articles by this author Nishant Singh More articles by this author Marc Connell More articles by this author Jodi Maranchie More articles by this author Christopher Chermansky More articles by this author Naoki Yoshimura More articles by this author Jonathan Kaufman More articles by this author Expand All Advertisement Loading ...

Image quality improvement of single-shot turbo spin-echo magnetic resonance imaging of female pelvis using a convolutional neural network.

We have developed a deep learning-based approach to improve image quality of single-shot turbo spin-echo (SSTSE) images of female pelvis. We aimed to compare the deep learning-based single-shot turbo spin-echo (DL-SSTSE) images of female pelvis with turbo spin-echo (TSE) and conventional SSTSE images in terms of image quality.One hundred five and 21 subjects were used as training and test sets, respectively. We performed 6-fold cross validation. In the training process, low-quality images were generated from TSE images as input. TSE images were used as ground truth images. In the test process, the trained convolutional neural network was applied to SSTSE images. The output images were denoted as DL-SSTSE images. Apart from DL-SSTSE images, classical filtering methods were adopted to SSTSE images. Generated images were denoted as F-SSTSE images. Contrast ratio (CR) of gluteal fat and myometrium and signal-to-noise ratio (SNR) of gluteal fat were measured for all images. Two radiologists graded these images using a 5-point scale and evaluated the image quality with regard to overall image quality, contrast, noise, motion artifact, boundary sharpness of layers in the uterus, and the conspicuity of the ovaries. CRs, SNRs, and image quality scores were compared using the Steel-Dwass multiple comparison tests.CRs and SNRs were significantly higher in DL-SSTSE, F-SSTSE, and TSE images than in SSTSE images. Scores with regard to overall image quality, contrast, noise, and boundary sharpness of layers in the uterus were significantly higher on DL-SSTSE and TSE images than on SSTSE images. There were no significant differences in the CRs, SNRs, and respective scores between DL-SSTSE and TSE images. The score with regard to motion artifacts was significantly higher on DL-SSTSE, F-SSTSE, and SSTSE images than on TSE images. The score with regard to the conspicuity of ovaries was significantly higher on DL-SSTSE images than on F-SSTSE, SSTSE, and TSE images (P < .001).DL-SSTSE images showed higher image quality as compared with SSTSE images. In comparison with conventional TSE images, DL-SSTSE images had acceptable image quality while keeping the advantage of the motion artifact-robustness and acquisition time efficiency in SSTSE imaging.

Rapid Magnetic Resonance Imaging of the Spine in Neonates with Spinal Dysraphism

The use of nonsedated T2-weighted Half-Fourier Acquisition Single-shot Turbo spin Echo magnetic resonance imaging (MRI) sequences in screening for spinal cord syrinx in neonates with spinal dysraphism has not been reported in the literature. We sought to review our experience using T2-weighted Half-Fourier Acquisition Single-shot Turbo spin Echo imaging of the spine (i.e., rapid spine MRI) in nonsedated neonates for detecting spinal cord syrinx in neonates with spinal dysraphism. We performed a retrospective search of our radiology database for neonates with spinal dysraphism who had rapid spine MRI between May 2017 and February 2020. The images were reviewed in conjunction with clinical findings and standard spine imaging, when available. Thirty studies (in 29 neonates) fulfilled our inclusion criteria. Of the 26 neonates with myelomeningocele, 5 of them (19%) had spinal cord syrinx identified on neonatal rapid spine MRI. An additional 2 patients developed syrinx by 2 years of age. Potential pitfalls identified in interpreting rapid spine MRI include motion artifacts and distinguishing a severe holocord syrinx from a truncated spinal cord. Rapid spine MRI acquired without sedation or anesthesia may be used as a screening technique to detect spinal cord syrinx in neonates with spinal dysraphism.

A novel amplitude binning strategy to handle irregular breathing during 4DMRI acquisition: improved imaging for radiotherapy purposes

BackgroundFor radiotherapy of abdominal cancer, four-dimensional magnetic resonance imaging (4DMRI) is desirable for tumor definition and the assessment of tumor and organ motion. However, irregular breathing gives rise to image artifacts. We developed a outlier rejection strategy resulting in a 4DMRI with reduced image artifacts in the presence of irregular breathing.MethodsWe obtained 2D T2-weighted single-shot turbo spin echo images, with an interleaved 1D navigator acquisition to obtain the respiratory signal during free breathing imaging in 2 patients and 12 healthy volunteers. Prior to binning, upper and lower inclusion thresholds were chosen such that 95% of the acquired images were included, while minimizing the distance between the thresholds (inclusion range (IR)). We compared our strategy (Min95) with three commonly applied strategies: phase binning with all images included (Phase), amplitude binning with all images included (MaxIE), and amplitude binning with the thresholds set as the mean end-inhale and mean end-exhale diaphragm positions (MeanIE). We compared 4DMRI quality based on:Data included (DI); percentage of images remaining after outlier rejection.Reconstruction completeness (RC); percentage of bin-slice combinations containing at least one image after binning.Intra-bin variation (IBV); interquartile range of the diaphragm position within the bin-slice combination, averaged over three central slices and ten respiratory bins.IR.Image smoothness (S); quantified by fitting a parabola to the diaphragm profile in a sagittal plane of the reconstructed 4DMRI.A two-sided Wilcoxon’s signed-rank test was used to test for significance in differences between the Min95 strategy and the Phase, MaxIE, and MeanIE strategies.ResultsBased on the fourteen subjects, the Min95 binning strategy outperformed the other strategies with a mean RC of 95.5%, mean IBV of 1.6 mm, mean IR of 15.1 mm and a mean S of 0.90. The Phase strategy showed a poor mean IBV of 6.2 mm and the MaxIE strategy showed a poor mean RC of 85.6%, resulting in image artifacts (mean S of 0.76). The MeanIE strategy demonstrated a mean DI of 85.6%.ConclusionsOur Min95 reconstruction strategy resulted in a 4DMRI with less artifacts and more precise diaphragm position reconstruction compared to the other strategies.Trial registrationVolunteers: protocol W15_373#16.007; patients: protocol NL47713.018.14

Feasibility of automated 3-dimensional magnetic resonance imaging pancreas segmentation

PurposeWith the advent of magnetic resonance imaging (MRI) guided radiation therapy, internal organ motion can be imaged simultaneously during treatment. In this study, we evaluate the feasibility of pancreas MRI segmentation using state-of-the-art segmentation methods. Methods and materialsT2-weighted half-Fourier acquisition single-shot turbo spin-echo and T1 weighted volumetric interpolated breath-hold examination images were acquired on 3 patients and 2 healthy volunteers for a total of 12 imaging volumes. A novel dictionary learning (DL) method was used to segment the pancreas and compared to t mean-shift merging, distance regularized level set, and graph cuts, and the segmentation results were compared with manual contours using Dice's index, Hausdorff distance, and shift of the center of the organ (SHIFT). ResultsAll volumetric interpolated breath-hold examination images were successfully segmented by at least 1 of the autosegmentation method with Dice's index >0.83 and SHIFT ≤2 mm using the best automated segmentation method. The automated segmentation error of half-Fourier acquisition single-shot turbo spin-echo images was significantly greater. DL is statistically superior to the other methods in Dice’s overlapping index. For the Hausdorff distance and SHIFT measurement, distance regularized level set and DL performed slightly superior to the graph cuts method, and substantially superior to mean-shift merging. DL required least human supervision and was faster to compute. ConclusionsOur study demonstrated potential feasibility of automated segmentation of the pancreas on MRI scans with minimal human supervision at the beginning of imaging acquisition. The achieved accuracy is promising for organ localization.

Novel MRI finding for diagnosis of invasive placenta praevia: evaluation of findings for 65 patients using clinical and histopathological correlations

To review established magnetic resonance (MR) criteria and describe a new MR finding for the diagnosis of invasive placenta praevia. A retrospective review of prenatal MRI examinations of 65 patients (median age: 35years) who underwent MR for the screening of invasive placenta praevia. All MRIs were performed on a 1.5-T unit, including axial, coronal and sagittal T2-weighted half-Fourier single-shot turbo spin echo imaging. Fifteen patients were diagnosed with invasive placenta praevia. Two experienced radiologists reviewed the MR images and evaluated a total of six MRI features of the placenta, including our novel finding of the placental protrusion into the internal os (placental protrusion sign). Inter-rater reliability was assessed by using kappa statistics. Features with a kappa statistic >0.40 were evaluated using Fisher's two-sided exact test for comparison of their capabilities for placental invasion assessment. Interobserver reliability was moderate or better for the intraplacental T2 dark band, intraplacental abnormal vascularity, uterine bulging, heterogeneous placenta and placental protrusion sign. Fisher's two-sided exact test results showed all these features were significantly associated with invasive placenta praevia. The novel MRI finding of a placental protrusion sign is a useful addition to the established MRI findings for the diagnosis of invasive placenta praevia. • Prenatal diagnosis for an invasive placenta is essential for perinatal planning. • Magnetic resonance imaging provides useful information for the diagnosis of invasive placenta. • The placental protrusion sign is a useful novel MRI finding for predicting invasive placenta.

Decidualized adenomyosis during pregnancy and post delivery: three cases of magnetic resonance imaging findings

Adenomyosis is a common gynecologic disease. Pregnancy with adenomyosis is on the increase due to a tendency of delay with first pregnancies and various infertility treatments involved in the process. We encountered decidualized adenomyosis in three patients during pregnancy, who were suspected by magnetic resonance (MR) imaging and were followed monitored post delivery. The MR imaging findings of adenomyosis during pregnancy showed low signal intensity areas with embedded bright foci that expanded to a few mm in diameter on half Fourier single-shot turbo spin-echo images. This finding may reflect decidual change of the stroma within the ectopic endometrium caused during pregnancy. The MR imaging findings of adenomyosis after childbirth showed hemorrhage inside the lesion, which were assumed to be led by rapid decrease in a blood flow to adenomyosis post childbirth.

Small Focal Hepatic Lesions ≤1 cm: Their Detection and Characterization with Performing Diffusion-Weighted Sensitivity-Encoding versus SPIO-Enhanced 3T MR Imaging

Purpose: We wanted to compare the accuracy of 3T DW-SENSE imaging with that of SPIO-enhanced imaging for the detection and characterization of small hepatic lesions. Materials and Methods: 124 focal hepatic lesions of 42 patients were retrospectively reviewed. The DWSENSE imaging and four T2-weighted imaging, including the respiratory-triggered and breath-hold fast spinecho images, the half-fourier single-shot turbo spin-echo images and the T2*-weighted fast field-echo images, were acquired. Four T2-weighted examinations were performed after administering SPIO. The images were divided into two sets: the SPIO image set (four pre- and post-contrast T2-weighted images) and the DW-SENSE image set (four DW-SENSE and pre-contrast T2-weighted images). These were sorted according to the confidence levels for lesion detection and characterization into four and five grades. The ROC curve (Az) was calculated. Results: The detection accuracy with using the DW-SENSE image set (Az=0.932, 0.889) was higher than with using the SPIO image set (Az=0.852, 0.798) for all the lesions and the small lesions (≤ 1 cm) (p

Lumps and Bumps on the Head in Children: Use of CT and MR Imaging in Solving the Clinical Diagnostic Dilemma

Lumps and bumps of the scalp are a common presenting complaint in children and often pose a diagnostic dilemma. These lesions can be difficult to image, with evaluation confounded by their small size. However, accuracy in diagnosis is critical because the diagnostic and therapeutic implications can vary significantly. The clinical examination can be helpful in developing the differential diagnosis and the imaging strategy. Often, however, a single imaging study is insufficient, and the radiologist finds it necessary to image with more than one modality to correctly diagnose a lesion and provide adequate information for the surgeon. Radiography and ultrasonography are often the initial screening diagnostic tests, followed by magnetic resonance (MR) imaging or computed tomography (CT) for more detail. Multidetector thin-section CT and thin-section MR imaging with surface coils are beneficial in the work-up of these small lesions of the head and neck. The use of newer MR imaging sequences such as heavily T2-weighted single-shot turbo spin-echo imaging and diffusion-weighted imaging can improve the characterization of difficult lesions. Familiarity with the variety of new imaging tools and techniques that are available can help characterize pediatric head and neck lesions and guide clinical management.

Application of SENSE in clinical pediatric body MR imaging.

Pediatric body magnetic resonance imaging can be challenging because of the intrinsic physiologic motions from high respiratory and heart rates. Unlike in adults, in preadolescent children, breath holding is often not an available option. In this paper, the authors describe their clinical experience using the recently available parallel imaging technique, sensitivity encoding (SENSE), to improve on the image quality of pediatric body MR examinations. The three major areas described include rapid imaging using SENSE to achieve time-resolved contrast-enhanced MRA, improvement in single-shot turbo spin echo imaging with SENSE, and decreasing respiratory motion artifact with combination of SENSE and multiple signal averages in various pulse sequences. Some practical suggestions of using SENSE in clinical pediatric body MR examinations are highlighted. The addition of SENSE has allowed for improved image quality and more efficient overall MR examinations for pediatric body imaging.

MR-guided percutaneous drainage of abdominal fluid collections in combination with X-ray fluoroscopy: initial clinical experience.

The aim of this study was to examine the feasibility of a hybrid interventional MR system, which combines a closed bore magnet with a C-arm fluoroscopy unit for percutaneous drainage of abdominal fluid collections. During the past 2 years, we have performed four drainage procedures in four patients (mean age 47 years). Three patients had abscesses (psoas muscle, kidney, subphrenic location) and the fourth patient had a recurrent splenic cyst. All procedures were performed on an interventional MR system consisting of a 1.5-T ACS-NT scanner combined with a specially shielded C-arm. The drainages were guided by T1-weighted fast gradient-echo images, T2-weighted single-shot turbo spin-echo images or both. A standard 18 G (1.2 mm) nonferromagnetic stainless steel needle with a Teflon sheath was used for the punctures following which a 0.89 mm nitinol guidewire was inserted into the fluid collection. Thereafter, the patient was positioned in the immediate adjacent fluoroscopy unit and a drainage catheter was placed under fluoroscopic control. All drainage catheters were successfully placed into the fluid collections, as proven by fluid aspiration and resolution of the collection. The mean time needed for the entire drainage procedure (MR and fluoroscopy) was 110 min. No procedure-related complications occurred. It is feasible to perform drainage procedures on a closed-bore MR scanner. The multiplanar imaging capabilities of MR are particularly helpful for fluid collections in the subphrenic location.