Turbo Spin-echo Sequence Research Articles

Applicability of proximal humeral epiphysis ossification for forensic age estimation according to the Vieth method: a 3.0 T MRI study

A retrospective study was conducted to explore the possibility of determining the age of majority via examination of the proximal humeral epiphyseal-diaphyseal fusion by 3.0 T magnetic resonance imaging (MRI) using the Vieth classification. Proximal humeral epiphyses were retrospectively studied on 3.0 T MRI in 315 participants (122 females, 193 males) between 10 and 28 years of age, using T1-weighted turbo spin echo (T1W TSE) and proton density fat-saturated TSE sequence (PD FS TSE). A 5-stage scoring system was used following the method of Vieth et al. The relevant statistics were defined, the intraobserver and interobserver agreements were determined (Cohen’s kappa) and the differences between the sexes were analyzed (Mann-Whitney U‑test, p 0.05). The Vieth classification provides important information in determining whether a person has reached the age of 18 years or not in both sexes through 3.0 T MRI of the shoulder joint.

Safety of 3 Tesla Magnetic Resonance Imaging on iStent Implants: An Ex-Vivo Study.

Our study shows that iStent implant does not cause significant image artifacts, heating, or displacement during magnetic resonance imaging (MRI) scan. This device can be safely used in patients undergoing MRI scans using 3 Tesla (3T) machines. The iStent is a medical grade titanium implant commonly implanted in the anterior chamber angle of glaucomatous eyes in order to reduce intraocular pressure and medication burden. As many people now have these devices implanted in their eyes, the issue of their compatibility with MRI in terms of safety and interference with interpretation of these studies commonly arises. The purpose of this study is to evaluate the safety of 3T MRI scans in eyes that have undergone iStent implantation and to assess the interference of the implant to the scan interpretation. An ex vivo model of sheep eye with an iStent and proximately placed heat detector probe was used to study changes in the temperature during MRI 3T scan. The study included 2 fresh eyes with preserved extraocular muscles and orbital fat tissue placed in the orbital cavity of a human skull. Each eye with orbital content was scanned with a 3T MRI machine. No displacement of the implant was observed during MRI scanning. The heat detector showed mild temperature elevation during the first minutes of the scan from 14.6 to 16.5°C. The iStent was best visualized in T2 turbo spin echo sequences and showed no significant artifacts. iStent implants did not move during the MRI scan, showed minimal interaction with the magnetic field in terms of heating and image distortion. These interactions were not strong enough to present a substantial risk to patients with this implant undergoing an MRI scan.

Clear and Consistent Imaging of Hippocampal Internal Architecture With High Resolution Multiple Image Co-registration and Averaging (HR-MICRA).

Magnetic resonance imaging of hippocampal internal architecture (HIA) at 3T is challenging. HIA is defined by layers of gray and white matter that are less than 1 mm thick in the coronal plane. To visualize HIA, conventional MRI approaches have relied on sequences with high in-plane resolution (≤0.5 mm) but comparatively thick slices (2–5 mm). However, thicker slices are prone to volume averaging effects that result in loss of HIA clarity and blurring of the borders of the hippocampal subfields in up to 61% of slices as has been reported. In this work we describe an approach to hippocampal imaging that provides consistently high HIA clarity using a commonly available sequence and post-processing techniques that is flexible and may be applicable to any MRI platform. We refer to this approach as High Resolution Multiple Image Co-registration and Averaging (HR-MICRA). This approach uses a variable flip angle turbo spin echo sequence to repeatedly acquire a whole brain T2w image volume with high resolution in three dimensions in a relatively short amount of time, and then co-register the volumes to correct for movement and average the repeated scans to improve SNR. We compared the averages of 4, 9, and 16 individual scans in 20 healthy controls using a published HIA clarity rating scale. In the body of the hippocampus, the proportion of slices with good or excellent HIA clarity was 90%, 83%, and 67% for the 16x, 9x, and 4x HR-MICRA images, respectively. Using the 4x HR-MICRA images as a baseline, the 9x HR-MICRA images were 2.6 times and 16x HR-MICRA images were 3.2 times more likely to have high HIA ratings (p < 0.001) across all hippocampal segments (head, body, and tail). The thin slices of the HR-MICRA images allow reformatting in any plane with clear visualization of hippocampal dentation in the sagittal plane. Clear and consistent visualization of HIA will allow application of this technique to future hippocampal structure research, as well as more precise manual or automated segmentation.

Three-Dimensional Volumetric Magnetic Resonance Imaging Detects Early Alterations of the Brain Growth in Fetuses With Congenital Heart Disease.

Several published studies have shown alterations of brain development in third-trimester fetuses with congenital heart disease (CHD). However, little is known about the timing and pattern of altered brain development in fetuses with CHD. To investigate the changes in the volume of intracranial structures in fetuses with CHD by three-dimensional (3D) volumetric magnetic resonance imaging (MRI) in the earlier stages of pregnancy (median gestational age [GA], 26 weeks). Retrospective. Forty women carrying a fetus with CHD (including 20 fetuses with GA <26 weeks) and 120 pregnant women carrying a healthy fetus (including 50 fetuses with GA <26 weeks). Two-dimensional single-shot turbo spin echo sequence at 1.5-T. Three-dimensional volumetric parameters from slice-to-volume registered images, including cortical gray matter volume (GMV), subcortical brain tissue volume (SBV), intracranial cavity volume (ICV), lateral ventricles volume (VV), cerebellum, brainstem, and extra-cerebrospinal fluid (e-CSF) were quantified by manual segmentation from one primary and two secondary observers. Volumes were presented graphically with quadratic curve fitting. Scatterplots were produced mapping volumes against GA in normal and CHD fetuses. For GA <26 weeks, Z scores were calculated and Student's t-tests were conducted to compare volumes between the normal and CHD fetuses. In fetuses with CHD GMV, SBV, cerebellum, and brainstem were significantly reduced (all P < 0.05) in early stages of pregnancy (GA <26 weeks), with differences becoming progressively greater with increasing GA. Compared with normal fetuses, e-CSF, e-CSF to ICV ratio, and VV were higher in fetuses with CHD (all P < 0.05). However, ICV volume and the GMV to SBV ratio were not significantly reduced in the CHD group (P=0.94 and P=0.13, respectively) during the middle gestation (GA <26 weeks). There appear to be alterations of brain development trajectory in CHD fetuses that can be detected by 3D volumetric MRI in the earlier stages of pregnancy. 4 TECHNICAL EFFICACY: Stage 3.

Neural network enhanced 3D turbo spin echo for MR intracranial vessel wall imaging

PurposeTo improve the signal-to-noise ratio (SNR) and image sharpness for whole brain isotropic 0.5 mm three-dimensional (3D) T1 weighted (T1w) turbo spin echo (TSE) intracranial vessel wall imaging (IVWI) at 3 T. MethodsThe variable flip angle (VFA) method enables useful optimization across scan efficiency, SNR and relaxation induced point spread function (PSF) for TSE imaging. A convolutional neural network (CNN) was developed to retrospectively enhance the acquired TSE image with PSF blurring. The previously developed VFA method to increase SNR at the expense of blur can be combined with the presented PSF correction to yield long echo train length (ETL) scan while the acquired image remains high SNR and sharp. The overall approach can enable an optimized solution for accelerated whole brain high-resolution 3D T1w TSE IVWI. Its performance was evaluated on healthy volunteers and patients. ResultsThe PSF blurred image acquired by a long ETL scan can be enhanced by CNN to restore similar sharpness as a short ETL scan, which outperforms the traditional linear PSF enhancement approach. For accelerated whole brain IVWI on volunteers, the optimized isotropic 0.5 mm 3D T1w TSE sequence with CNN based PSF enhancement provides sufficient flow suppression and improved image quality. Preliminary results on patients further demonstrated its improved delineation for intracranial vessel wall and plaque morphology. ConclusionThe CNN enhanced VFA TSE imaging enables an overall image quality improvement for high-resolution 3D T1w IVWI, and may provide a better tradeoff across scan efficiency, SNR and PSF for 3D TSE acquisitions.

Rapid Musculoskeletal MRI in 2021: Clinical Application of Advanced Accelerated Techniques.

OBJECTIVE. The purpose of this article is to provide a practice-focused review of the clinical application of advanced acceleration techniques for rapid musculoskeletal MRI examinations. CONCLUSION. Parallel imaging, simultaneous multislice acquisition, compressed sensing-based sampling, and synthetic MRI techniques provide unprecedented opportunities for rapid musculoskeletal MRI examinations. For 2D and 3D fast spin-echo and turbo spin-echo pulse sequences, acceleration factors between 3 and 8 can be realized in clinical practice, amounting to a time savings of 66-85% when compared with unaccelerated acquisitions.

Bone Structure Analysis of the Radius Using Ultrahigh Field (7T) MRI: Relevance of Technical Parameters and Comparison with 3T MRI and Radiography.

Bone fractal signature analysis (FSA—also termed bone texture analysis) is a tool that assesses structural changes that may relate to clinical outcomes and functions. Our aim was to compare bone texture analysis of the distal radius in patients and volunteers using radiography and 3T and 7T magnetic resonance imaging (MRI)—a patient group (n = 25) and a volunteer group (n = 25) were included. Participants in the patient group had a history of chronic wrist pain with suspected or confirmed osteoarthritis and/or ligament instability. All participants had 3T and 7T MRI including T1-weighted turbo spin echo (TSE) sequences. The 7T MRI examination included an additional high-resolution (HR) T1 TSE sequence. Radiographs of the wrist were acquired for the patient group. When comparing patients and volunteers (unadjusted for gender and age), we found a statistically significant difference of horizontal and vertical fractal dimensions (FDs) using 7T T1 TSE-HR images in low-resolution mode (horizontal: p = 0.04, vertical: p = 0.01). When comparing radiography to the different MRI sequences, we found a statistically significant difference for low- and high-resolution horizontal FDs between radiography and 3T T1 TSE and 7T T1 TSE-HR. Vertical FDs were significantly different only between radiographs and 3T T1 TSE in the high-resolution mode; FSA measures obtained from 3T and 7T MRI are highly dependent on the sequence and reconstruction resolution used, and thus are not easily comparable between MRI systems and applied sequences.

Comparison of plaque characteristics of small and large subcortical infarctions in the middle cerebral artery territory using high-resolution magnetic resonance vessel wall imaging

The characteristics of plaque that ultimately lead to different subcortical infarctions remain unclear. We explored the differences in plaque characteristics between patients with small subcortical infarction (SSI) and large subcortical infarction (LSI) of the middle cerebral artery (MCA) using high-resolution magnetic resonance vessel wall imaging (HR-MRVWI). The study group comprised 71 patients (mean age, 47.49±11.5 years; 55 male) with MCA territory ischemic stroke. Whole-brain HR-MRVWI was performed using a three-dimensional T1-weighted variable-flip-angle turbo spin echo (SPACE) sequence. Patients were divided into SSI and LSI groups based on routine MRI images. Plaque distribution was classified as the superior, inferior, ventral, or dorsal wall of the MCA. The number of quadrants with plaque formation, location of plaque, plaque burden (PB), arterial remodeling pattern (positive or negative), and degree of stenosis were analyzed and compared between groups. Of the 71 patients, 43 (60.6%) and 28 (39.4%) were identified as the SSI and LSI groups, respectively. The proportion of plaques involving only one quadrant was significantly higher in the SSI group, and these plaques were located in the superior or dorsal MCA vessel wall. There was no significant difference between groups in the proportion of plaques involving two or more quadrants, plaque distribution, or PB. Most plaques in both groups showed positive remodeling, and the percentage of remodeling pattern was similar. A significantly higher incidence of low-grade stenosis (<50%) was observed in the SSI group. Both SSI and LSI may be associated with major intracranial artery atherosclerosis, but patients with SSI showed relatively fewer quadrants with plaque formation and a lesser degree of stenosis.

Role of different MRI sequences in evaluation of pediatric spinal dysraphism

ObjectiveThe aim was to assess type and extent of clinically evident or suspected spinal abnormalities by MRI and to compare different sequences for identifying nervous and fatty tissue in different abnormalities.BackgroundSpinal dysraphisms are congenital abnormalities of spine and spinal cord owing to faulty closure of midline structures. Imaging of spinal dysraphism should follow an organized approach and correlation between radiological, clinical, and developmental data should help in appropriate diagnosis. MRI is considered the best imaging modality for these abnormalities.Materials and MethodsPediatric patients aged 1 day till 2 years old, clinically evident or suspected to have spinal dysraphism, having back swelling, skin pigmentations, skin tags, hair tufts, hemangiomas of the back, criteria were included and underwent MR scan in Toshiba Excelart Vantage Titan (Japan) 1.5 Tesla MR Set with standard 16-channel head coil.ResultsOf 43 pediatric patients dated since birth till 2 years old with clinical evidence or suspicion of congenital spinal abnormalities for MRI scanning, spina bifida (41.9%), bony deformities (30.2%), tethered cord (27.9%), meningomyelocele (25.6%) were the commonest congenital spinal abnormalities. Neural tissues in the herniated thecal sac were detected in combination of three-dimentional half Fourier-acquired single-shot turbo spin echo (3D HASTE) sequence with turbo spin echo T1-weighted (TSE T1W) sequence in 15 patients, which was significantly high as compared with combinations of TSE T1W sequence with TSE T2 weighted (T2W), with short-time inversion recovery (STIR) and with single-shot myelographic sequence probability value of 0.03, 0.02, and 0.01, respectively. Fatty tissue was found in four cases, which were detected by a combination of STIR and TSE T1W sequences in all four patients.ConclusionPediatric spinal dysraphism and different spinal anomalies can be diagnosed by MRI scanning with excellent accuracy. STIR and 3D-HASTE sequences should be part of the examination protocol of spinal dysraphism.

Comparative Study of high-resolution T2-weighted turbo spin echo sequence and postcontrast three-dimensional volumetric T1-weighted sequence in evaluation of acute onset sensorineural hearing loss

Comparative Study of high-resolution T2-weighted turbo spin echo sequence and postcontrast three-dimensional volumetric T1-weighted sequence in evaluation of acute onset sensorineural hearing loss

Comparative Study of high-resolution T2-weighted turbo spin echo sequence and postcontrast three-dimensional volumetric T1-weighted sequence in evaluation of acute onset sensorineural hearing loss

Comparative Study of high-resolution T2-weighted turbo spin echo sequence and postcontrast three-dimensional volumetric T1-weighted sequence in evaluation of acute onset sensorineural hearing loss

Fetal Congenital Abnormalities: Clinical Utility of 3T MRI in Late 2nd &amp;amp; 3rd Trimesters

PURPOSE: To assess and compare utility of fetal MRI over prenatal ultrasound in management of fetal congenital abnormalities detected in late 2nd and 3rd trimesters (after legal limit of termination). METHODS: 3T MRI was performed in 43 pregnant women with period of gestation ≥20 weeks with suspected congenital abnormalities on ultrasound (USG). Half-Fourier acquisition single shot turbo spin echo sequence was used with T1 sequence wherever required. Ultrasonographic and MRI findings were compared and grouped as: findings concordant on both (Category I), MRI added information with no significant change in diagnosis (Category II), MRI added information with significant change in diagnosis (Category III) or USG superior to MRI (Category IV). Clinical utility of the fetal MRI was assessed in changing fetal prognostication and delivering peri/postnatal management with respect to USG in each of these categories. RESULTS: 18/43(41.8%) showed concordant USG and MRI findings without change in management. In 9/43(20.9%), MRI added information with no significant change in diagnosis causing change in prognosis and management in 4/9(44.4%) and 2/9(22.2%) respectively. In 15/43(34.9%), MRI added information with significant change in diagnosis that worsened prognosis in 13/15(86.7%) and aided in management in 6/15(40%). In 1/43(2.4%), USG was superior than MRI with no influence on management. CONCLUSIONS: Fetal MRI improves ultrasonographic diagnosis leading to change in fetal prognostication in a significant proportion of pregnancies. MRI can help in deciding mode of deliveries. It can act as a preliminary imaging which aids in post-natal management in an unstable baby where cross-sectional imaging is difficult. Funding Information: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors. Declaration of Interests: None. Ethics Approval Statement: Ethical clearance was obtained from the institutional ethics committee.

An unusual case of oedematous prostate volumetric changes observed over the course of radiotherapy on the MR linear accelerator

IntroductionThe integration of magnetic resonance (MR) imaging into radiotherapy through new technology, including the MR -linear accelerator (MRL), has allowed further advancements into image guided radiotherapy (IGRT). Better soft tissue visualisation has led to some unusual findings. Case and outcomesA patient with T1c N0 M0 prostate adenocarcinoma received 60Gy in 20# radiotherapy on the MRL. Radiotherapy planning (RTP) scans were completed on both CT and MR (using T2 and T1 weighted three-dimensional turbo spin echo sequences, reconstructed transaxially (TRA). The MR scans revealed atypical oedema in the right peripheral zone, visualised on T2-weighted (T2w) MR Images as an accumulation of high signal intensity fluid. Daily MRL treatment includes a (T2w 3D Tra) sequence with which oedematous changes could be monitored. The images demonstrated an increase in oedematous volume over fractions 1–10 causing the prostate contour variations from the initial planning scans. Despite the prostate volume variations PTV coverage was never breached and dose constraints were always met for both PTV and surrounding organs at risk (OAR's), excluding the need for oncologist input.A single Therapeutic Radiographer (RTT) experienced in MRL delivery, contoured the prostate and oedematous volumes on the radiotherapy plan (RTP) MR and all on-treatment MR images to assess change over the radiotherapy course. The initial volumes were 53.4 cm3 and 8.3 cm3 for the prostate plus oedema and oedema alone respectively. The most significant change was seen for both the prostate and oedema on fraction nine (68.0 cm3 and 10.1 cm3, respectively). Reductions were noted after this with final (fraction 20) volumes of 55.2 cm3 and 0.58 cm3 respectively. DiscussionThe ability to visualise prostatic oedema was new to the radiotherapy treatment team due to better soft tissue visualisation than standard radiotherapy. The results from contouring the prostate and oedema volumes confirmed radiographer observations and demonstrated how oedema impacted the overall prostate volume by quantifying the oedematous variations over time. The changes in oedema volume are presumed to be in response to radiotherapy. ConclusionFurther adaptive radiotherapy work-flow developments, utilising an “Adapt to Shape” model will allow real-time re-contouring of the prostate to ensure tumour control is not compromised. Further work investigating the frequency and impact of oedemotous changes to external beam prostate patients will help to inform practice.

A comparative study of magnetic resonance imaging and arthroscopy in internal derangement of knee

The purpose of this study is to compare the findings of magnetic resonance imaging with arthroscopy in internal derangements of knee and to assess the sensitivity, specificity and accuracy of magnetic resonance imaging in comparison to arthroscopy. Methods and Materials: Fifty six patients with history of suspected internal derangement of knee were evaluated prospectively with MRI and compared with arthroscopy during a one and half a year period from January 2016 to June 2017 at Katuri Medical College & Hospitals, Chinakondrupadu, Guntur. 1.5 Tesla MRI machine using a closed extremity coil is used. Commonly used sequences in MRI of the knee include Turbo-spin echo (TSE), FFE (Gradient echo) and Short Tau Inversion Recovery (STIR) sequences in Axial, Sagittal and Coronal planes using a slice thickness of 3 mm with a 0.3 mm slice gap. Arthroscopy of the knee with standard anteromedial and anterolateral portals with the patient in supine position done in all the cases. Observations: The diagnostic sensitivity, specificity and accuracy of MRI in detecting cruciate ligament and meniscal injuries as compared to arthroscopy is as follows: Anterior Cruciate Ligament (ACL): 97.29%, 89.47%, 94.64% ; Posterior Cruciate Ligament (PCL): 100%, 100%, 100%; Medial Meniscus (MM): 100%, 93.33%, 98.21% and Lateral Meniscus (LM): 93.10, 92.59, 92.85. Most common lesions found were ACL and Medial Meniscal tears (posterior horn of MM being the most common site). Summary and Conclusion: MRI is a useful non-invasive modality having high sensitivity, specificity and accuracy in diagnosing cruciate ligament and meniscal injuries. MRI should be considered as the first line of investigation in all patients with suspected internal derangements of knee. MRI being easily available and non-invasive is useful as a pre-operative screening modality, thus improves the quality of diagnostic and therapeutic arthroscopies and further reduces the morbidity. Arthroscopy is the gold standard in diagnosing c

Evaluation of proximal humeral epiphysis ossification in 3.0 T MR images according to the Dedouit staging method: Is it be used for age of majority?

Magnetic resonance imaging (MRI) for forensic age estimation is among the research issues since it does not lead to radiation exposure. In this study, the ossification stage of the proximal humeral epiphysis was determined retrospectively in 178 male and 109 female individuals in the 12 to 30-year age group using 3.0 T MRI. All images were evaluated with the proton density fat saturated turbo spin echo (PD TSE FS) sequence and the T2 TSE FS sequence. A five-stage scoring system was used following the method of Dedouit et al. The relevant statistics were defined as minimum, maximum, mean ± standard deviation, 95% confidence interval of mean and median and the intra- and interobserver agreement levels were very good (κ > 0.80). There were no significant age differences between males and females in any of the stages (all p-values>0.05). According to the present study, stage 5 was initially observed at age 22 years for both genders. According to our results, it is possible to determine the completion of the 18th year of life in either gender on the shoulder joint. Proximal humeral epiphysis ossification may be used as an additional method for forensic age estimation through MRI.

Trabecular Bone Assessment Using Magnetic-Resonance Imaging: A Pilot Study.

The aim of this study was to assess trabecular bone morphology via magnetic-resonance imaging (MRI) using microcomputed tomography (µCT) as the control group. Porcine bone samples were scanned with T1-weighted turbo spin echo sequence imaging, using TR 25 ms, TE 3.5 ms, FOV 100 × 100 × 90, voxel size 0.22 × 0.22 × 0.50 mm, and scan time of 11:18. µCT was used as the control group with 80 kV, 125 mA, and a voxel size of 16 µm. The trabecular bone was segmented on the basis of a reference threshold value and morphological parameters. Bone volume (BV), Bone-volume fraction (BvTv), Bone specific surface (BsBv), trabecular thickness (TbTh), and trabecular separation (TbSp) were evaluated. Paired t-test and Pearson correlation test were performed at p = 0.05. MRI overestimated BV, BvTv, TbTh, and TbSp values. BsBv was the only parameter that was underestimated by MRI. High statistical correlation (r = 0.826; p < 0.05) was found for BV measurements. Within the limitations of this study, MRI overestimated trabecular bone parameters, but with a statistically significant fixed linear offset.

Towards real-time 4D radiation dosimetry on an MRI-Linac

4D radiation dosimetry using a highly radiation-sensitive polymer gel dosimeter with real-time quantitative magnetic resonance imaging (MRI) readout is presented as a technique to acquire the accumulated radiation dose distribution during image-guided radiotherapy on an MRI-Linac. Optimized T 2-weighted Turbo-Spin-Echo (TSE) scans are converted into quantitative ΔR 2 maps and subsequently to radiation dose maps.The concept of temporal uncertainty is introduced as a metric of effective temporal resolution. A mathematical framework is presented to optimize the echo time of the TSE sequence in terms of dose resolution, and the trade-off between temporal resolution and dose resolution is discussed. The current temporal uncertainty achieved with the MAGAT gel dosimeter on a 1 T MRI-Linac is 3.8 s which is an order of magnitude better than what has been achieved until now.The potential of real-time 4D radiation dosimetry in a theragnostic MRI-Linac is demonstrated for two scenarios: an irradiation with three coplanar beams on a head phantom and a dynamic arc treatment on a cylindrical gel phantom using a rotating couch. The dose maps acquired on the MRI-Linac are compared with a treatment plan and with dose maps acquired on a clinical 3 T MRI scanner. 3D gamma map evaluations for the different modalities are provided. While the presented method demonstrates the potential of gel dosimetry for tracking the dose delivery during radiotherapy in 4D, a shortcoming of the MAGAT gel dosimeter is a retarded dose response.The effect of non-ideal radiofrequency pulses resulting from limitations in the specific absorption rate or B1-field inhomogeneity on the TSE acquired ΔR 2 values is analysed experimentally and by use of computational modelling with a Bloch simulator.

Diagnostic Confidence and Feasibility of a Deep Learning Accelerated HASTE Sequence of the Abdomen in a Single Breath-Hold.

The aim of this study was to evaluate the feasibility of a single breath-hold fast half-Fourier single-shot turbo spin echo (HASTE) sequence using a deep learning reconstruction (HASTEDL) for T2-weighted magnetic resonance imaging of the abdomen as compared with 2 standard T2-weighted imaging sequences (HASTE and BLADE). Sixty-six patients who underwent 1.5-T liver magnetic resonance imaging were included in this monocentric, retrospective study. The following T2-weighted sequences in axial orientation and using spectral fat suppression were compared: a conventional respiratory-triggered BLADE sequence (time of acquisition [TA] = 4:00 minutes), a conventional multiple breath-hold HASTE sequence (HASTES) (TA = 1:30 minutes), as well as a single breath-hold HASTE with deep learning reconstruction (HASTEDL) (TA = 0:16 minutes). Two radiologists assessed the 3 sequences regarding overall image quality, noise, sharpness, diagnostic confidence, and lesion detectability as well as lesion characterization using a Likert scale ranging from 1 to 4 with 4 being the best. Comparative analyses were conducted to assess the differences between the 3 sequences. HASTEDL was successfully acquired in all patients. Overall image quality for HASTEDL was rated as good (median, 3; interquartile range, 3-4) and was significantly superior to HASTEs (P < 0.001) and inferior to BLADE (P = 0.001). Noise, sharpness, and artifacts for HASTEDL reached similar levels to BLADE (P ≤ 0.176) and were significantly superior to HASTEs (P < 0.001). Diagnostic confidence for HASTEDL was rated excellent by both readers and significantly superior to HASTEs (P < 0.001) and inferior to BLADE (P = 0.044). Lesion detectability and lesion characterization for HASTEDL reached similar levels to those of BLADE (P ≤ 0.523) and were significantly superior to HASTEs (P < 0.001). Concerning the number of detected lesions and the measured diameter of the largest lesion, no significant differences were found comparing BLADE, HASTES, and HASTEDL (P ≤ 0.912). The single breath-hold HASTEDL is feasible and yields comparable image quality and diagnostic confidence to standard T2-weighted TSE BLADE and may therefore allow for a remarkable time saving in abdominal imaging.

Evaluation of knee ossification on 1.5 T magnetic resonance images using the method of Vieth et al.

Magnetic resonance imaging (MRI) is a non-invasive method with the absence of ionizing radiation exposure and is therefore, preferable in studies for forensic age estimation. The purpose of this study was to investigate the degree of ossification of the knee in a Turkish population following the Vieth et al. method. We scanned 709 Turkish patients in the age bracket 12–27 years utilizing a T1-weighted (T1W) turbo spin echo sequence (TSE) and a T2‑W TSE sequence with fat suppression by spectral presaturation with inversion recovery. Minimum, maximum, mean ± standard deviation and median values were defined. Intraobserver and interobserver correlations were determined (Cohen’s kappa). The statistical relevance of sex-related differences was analyzed (Student’s t-test, Mann-Whitney U-test, p < 0.05, exact test, two-sided). The kappa statistics were relatively high, indicating very good agreement for interobserver and intraobserver evaluations. Comparison of male and female data revealed significant between-gender differences for most stages (p < 0.05). The earliest mean ages at which ossification of stages 4, 5 and 6 were evident in the distal femoral epiphysis were 14.84, 15.81, and 20.76 years in males and 13.77, 14.77, and 20.45 years in females, respectively. Proximal tibial epiphysis of stages 4, 5, and 6 ossification was first noted at ages 13.57, 15.59, and 18.91 years in males and 13.29, 14.38, and 16.87 years in females, respectively. In the distal femoral epiphysis, stage 6 was found at 20 years of age for both genders and it can be employed to differentiate above and below the majority age cut-off.

Evaluation of optimised 3D turbo spin echo and gradient echo MR pulse sequences of the knee at 3T and 1.5T

IntroductionTo investigate the impact of parameter optimisation for novel three-dimensional 3D sequences at 1.5T and 3T on resultant image quality. MethodsFollowing institutional review board approval and acquisition of informed consent, MR phantom and knee joint imaging on healthy volunteers (n = 16) was performed with 1.5 and 3T MRI scanners, respectively incorporating 8- and 15-channel phased array knee radiofrequency coils. The MR phantom and healthy volunteers were prospectively scanned over a six-week period. Acquired sequences included standard two-dimensional (2D) turbo spin echo (TSE) and novel three-dimensional (3D) TSE PDW (SPACE) both with and without fat-suppression, and T2∗W gradient echo (TrueFISP) sequences. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured for knee anatomical structures. Two musculoskeletal radiologists evaluated anatomical structure visualisation and image quality. Quantitative and qualitative findings were investigated for differences using Friedman tests. Inter- and intra-observer agreements were determined with κ statistics. ResultsPhantom and healthy volunteer images revealed higher SNR for sequences acquired at 3T (p-value <0.05). Generally, the qualitative findings ranked images acquired at 3T higher than corresponding images acquired at 1.5T (p < 0.05). 3D image data sets demonstrated less sensitivity to partial volume averaging artefact (PVA) compared to 2D sequences. Inter- and intra-observer agreements for evaluation across all sequences ranged from 0.61 to 0.79 and 0.71 to 0.92, respectively. ConclusionBoth 2D and 3D images demonstrated higher image quality at 3T than at 1.5T. Optimised 3D sequences performed better than the standard 2D PDW TSE sequence for contrast resolution between cartilage and joint fluid, with reduced PVA artefact. Implications for practiceWith rapid advances in MRI scanner technology, including hardware and software, the optimisation of 3D MR pulse sequences to reduce scan time while maintaining image quality, will improve diagnostic accuracy and patient management in musculoskeletal MRI.