Supine Magnetic Resonance Imaging Research Articles

Medial meniscus extrusion is associated with meniscus tears in US and MRI: A case control study.

To study the medial meniscus extrusion (MME) in subjects with and without medial meniscal tears on magnetic resonance imaging (MRI), supine ultrasound (US), and weight-bearing US. Forty-seven cases (mean age 43.7 years) with medial meniscus tears and 53 healthy controls (mean age 36.6 years) were assessed. Two experienced sonographers performed the US evaluations, and a fellowship-trained musculoskeletal radiologist assessed the menisci on MRI. Independent and paired T-tests and ICC were used for statistical analyses. On supine US, the mean MME was 3.9 mm for the cases and 2.3 mm for the controls (p < 0.001). On weight-bearing US, the values were 4.2 and 2.8 mm (p < 0.001), and on MRI 3.0 and 2.0 mm (p < 0.001), respectively. The mean difference between supine and weight-bearing US extrusion was 0.38 mm for the cases and 0.49 mm for the controls (p = 0.291). Correlation between supine US and MRI MME measurements was good (ICC = 0.660, CIs [0.533-0.758]). MME can be assessed using US with good correlation to MRI. US-observed extrusion was significantly increased in supine and standing positions for medial meniscus tears. The mean difference between examination positions was reduced with medial meniscus tears although this result was statistically insignificant.

Abstract PO2-07-08: The efficacy of an MRI/US fusion technique for MRI-detected lesions previously undetected by conventional B-mode second-look US

Abstract Introduction Breast magnetic resonance imaging (MRI) is performed for preoperative screening of breast cancer and surveillance of BRCA gene carriers, and some lesions, called MRI-detected lesions, can only be detected by MRI. When MRI-detected lesions are found, second-look ultrasound (US) is recommended as the first choice for confirmation. However, the detection of MRI-detected lesions by conventional B-mode (cB-mode) second-look US varies from institution to institution, and it is often difficult to ensure objectivity and reproducibility. We use an MRI/US fusion technique called real-time virtual sonography (RVS) for the detection of MRI-detected lesions. RVS uses a magnetic position tracking system to display real-time US images on the same monitor as MRI images. Few reports on second-look US using RVS have examined its detection rate of MRI-detected lesions and the histopathological results of these lesions. In this study, we retrospectively reviewed MRI-detected lesions identified by second-look US using RVS but not by cB-mode second-look US from January 2018 to December 2022, with the goal of evaluating these lesions’ pathological characteristics. Materials and methods Consecutive patients who had one or more MRI-detected lesions not detected by cB-mode second-look US were enrolled in this study between January 2018 and December 2021. Second-look US using RVS was conducted after an additional supine MRI with a body surface coil was performed. Results A total of 36 patients with 38 lesions were included in this study. The mean age was 54 years old (range: 31–76). We were able to detect 31 (82%) of the 39 MRI-detected lesions by second-look US using RVS. These lesions were characterized as follows: mass, 14; non-mass-enhancement (NME), 13; and focal, 4. US-guided biopsy or excisional biopsy was performed on all lesions, and 11 (35%) of 31 lesions were malignant. We were able to detect 14 (74%) of the 19 mass lesions, and 3 were malignant (invasive ductal carcinoma (IDC) [luminal A type] in all 3 cases). We detected 13 (93%) of the 14 NME lesions, and 7 were malignant: 6 were ductal carcinoma in situ (DCIS) (high grade, 3; intermediate grade, 2; and low grade, 1), and 1 was IDC (luminal A type). Finally, we were able to detect 4 (80%) of the 5 focal lesions, 1 of which was malignant (DCIS [low grade]). Of 22 patients aged 55 years or younger, 3 had malignant lesions (IDC [luminal A type] in 2, DCIS [high grade] in 1). Of 15 patients aged 56 years or older, 8 had malignant lesions (DCIS in 7 [high grade, 2; intermediate grade, 2; low grade, 1] and IDC [luminal A type] in 1). Conclusions In this study, second-look US using RVS identified 82% of MRI-detected lesions that were not identified with cB-mode second-look US. Of these MRI-detected lesions, 35% were malignant. These results suggest that second-look US using RVS is useful for identifying MRI-detected lesions that are not detected by cB-mode second-look US. Citation Format: Masayuki Saito, Hirona Banno, Yukie Ito, Mirai Ido, Manami Goto, Takahito Ando, Yukako Mouri, Junko Kousaka, Kmihito Fujii, Tsuneo Imai, Shogo Nakano. The efficacy of an MRI/US fusion technique for MRI-detected lesions previously undetected by conventional B-mode second-look US [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-07-08.

Lumbar Spine Anatomy in Supine versus Weight- Bearing Magnetic Resonance Imaging: Detecting Significant Positional Changes and Testing Reliability of Quantification.

Testing between and within group differences and assessing reliability of measurements. To study and compare lumbar spine morphology in supine and weight-bearing (WB) magnetic resonance imaging (MRI). Upright lumbar MRI may uncover anatomical changes that may escape detection when using conventional supine imaging. This study quantified anatomical dimensions of the lumbar spine in the supine and WB MRI, compared specific morphometric differences between them, and tested the intra-rater reliability of the measurements. Repeated measures analysis was used to compare within- and between-session measurements performed on the supine and WB images. Reliability and agreement were assessed by calculating intraclass correlation (ICC) coefficient. Data from 12 adults without any history of back pain were used in this study. Sagittal T2-weighted images of the lumbar spine were acquired in the supine and WB positions twice (in two separate sessions scheduled within a week). Linear, angular dimensions, and cross-sectional areas (CSAs) were measured using proprietary software. Supine and WB data acquired from the two imaging sessions were tested for intra-rater reliability. Quantified data were normalized for each session to test the significance of differences. ICC was calculated to test the reliability of the measurements. Linear, angular, and CSA measurements demonstrated strong within-position (supine and WB) correlations (r -values, 0.75-0.97). Between-position (supine vs. WB) differences were significant for all measured dimensions (p<0.05). Between-session measurements demonstrated a strong correlation (r -values, 0.64-0.83). Calculated ICC showed strong agreement among the measurements. Anatomical dimensions of the lumbar spine may demonstrate consistent and significant differences between supine and WB MRI for specific structural parameters.

Odontoid incidence: a constant cervical anatomical feature evident in standing plain radiographs and supine magnetic resonance images

ObjectiveTo assess whether there is a difference between measurements of odontoid incidence (OI) and other cervical sagittal parameters by X-ray radiography and those by supine magnetic resonance imaging (MRI).MethodsStanding X-ray and supine MRI images of 42 healthy subjects were retrospectively analyzed. Surgimap software was employed to measure cervical sagittal parameters including OI, odontoid tilt (OT), C2 slope (C2S), C0-2 angle, C2-7 angle, T1 slope (T1S) and T1S-cervical lordosis (CL). Paired samples t-test was applied to determine the difference between parameters measured by standing X-ray and those by supine MRI. In addition, the statistical correlation between the parameters were compared. The prediction of CL was performed and validated using the formula CL = 0.36 × OI − 0.67 × OT − 0.69 × T1S.ResultsSignificant correlations and differences were found between cervical sagittal parameters determined by X-ray and those by MRI. OI was verified to be a constant anatomic parameter and the formula CL = 0.36 × OI − 0.67 × OT − 0.69 × T1S can be used to predict CL in cervical sagittal parameters.ConclusionsOI is verified as a constant anatomic parameter, demonstrating the necessity of a combined assessment of cervical sagittal balance by using standing X-ray and supine MRI. The formula CL = 0.36 × OI − 0.67 × OT − 0.69 × T1S can be applied to predict CL in cervical sagittal parameters.

Upper and lower cervical alignment parameters measured on supine magnetic resonance imaging with the occipital slope as a key marker of cervical alignment.

Cervical spine alignment is evaluated by measuring the cervical angles or parameters on standing plain radiography. In this study, we aimed to evaluate mainly the upper cervical alignment and the correlation between upper and lower cervical sagittal parameters measured on supine magnetic resonance imaging (MRI). Cervical MRIs of 210 outpatients were reviewed to measure the upper and lower cervical sagittal parameters. Their mean values were compared with normative values measured on standing X-ray from the literature. Correlations between the parameters were analyzed using the Pearson's correlation coefficient. The C0 slope was correlated with all other parameters, except for the C2-7 sagittal vertical axis. The strongest correlations (r > 0.500) were between the CL and C2 slope, between the CO2 and C0 slope, and between the C2 slope and C0 slope. On supine MRI, the C0 slope is a key marker of cervical spinal alignment. A strong correlation was observed between the C2 slope and C0 slope; therefore, the relationship between upper and lower cervical alignment could be assessed using slopes on MRI.

Endograft position and endoleak detection after endovascular abdominal aortic repair with low-field tiltable MRI: a feasibility study

BackgroundAbdominal aortic endoleaks after endovascular aneurysm repair might be position-dependent, therefore undetectable using supine imaging. We aimed to determine the feasibility and benefit of using a low-field tiltable magnetic resonance imaging (MRI) scanner allowing to study patients who can be imaged in both supine and upright positions of endoleaks.MethodsTen EVAR patients suspected of endoleak based on ultrasound examination were prospectively included. MRI in upright and supine positions was compared with routine supine computed tomography angiography (CTA). Analysis was performed through (1) subjective image quality assessment by three observers, (2) landmark registration between MRI and CTA scans, (3) Euclidean distances between renal and endograft landmarks, and (4) evaluation of endoleak detection on MRI by a consensus panel. Statistical analysis was performed by one-way repeated measures analysis of variance.ResultsThe image quality of upright/supine MRI was inferior compared to CTA. Median differences in both renal and endograft landmarks were approximately 6–7 mm between upright and supine MRI and 5–6 mm between supine MRI and CTA. In the proximal sealing zone of the endograft, no differences were found among all three scan types (p = 0.264). Endoleak detection showed agreement between MRI and CTA in 50% of the cases, with potential added value in only one patient.ConclusionsThe benefit of low-field upright MRI for endoleak detection was limited. While MRI assessment was non-inferior to standard CTA in detecting endoleaks in selected cases, improved hardware and sequences are needed to explore the potential of upright MRI in patients with endoleaks.Relevance statementUpright low-field MRI has limited clinical value in detecting position-dependent endoleaks; improvements are required to fulfil its potential as a complementary modality in this clinical setting.Key points• Upright MRI shows potential for imaging endoleaks in aortic aneurysm patients in different positions.• The image quality of upright MRI is inferior to current techniques.• Upright MRI complements CTA, but lacks accurate deformation measurements for clinical use.• Advancements in hardware and imaging sequences are needed to fully utilise upright MRI capabilities.Graphical

Customised 3D-Printed Surgical Guide for Breast-Conserving Surgery after Neoadjuvant Chemotherapy and Its Clinical Application.

For patients eligible to undergo breast-conserving surgery (BCS) after neoadjuvant chemotherapy, accurate preoperative localisation of tumours is vital to ensure adequate tumour resection that can reduce recurrence probability effectively. For this reason, we have developed a 3D-printed personalised breast surgery guide (BSG) assisted with supine magnetic resonance imaging (MRI) and image 3D reconstruction technology, capable of mapping the tumour area identified on MRI onto the breast directly using dual positioning based on the manubrium and nipple. In addition, the BSG allows the colour dye to be injected into the breast to mark the tumour region to be removed, yielding more accurate intraoperative resection and satisfactory cosmetic outcomes. The device has been applied to 14 patients from January 2018 to July 2023, with two positive margins revealed by the intraoperative biopsy. This study showed that the BSG-based method could facilitate precise tumour resection of BCS by accurately localising tumour extent and margin, promoting the clinical efficacy in patients with breast cancer as well as simplifying the surgical process.

The Effect of Intraoperative Prone Position on Psoas Morphology and Great Vessel Anatomy: Consequences for Prone Lateral Approach to the Lumbar Spine

This study sought to quantify radiographic differences in psoas morphology, great vessel anatomy, and lumbar lordosis between supine and prone intraoperative positioning to optimize surgical planning and minimize the risk of neurovascular injury. Measurements on supine magnetic resonance imaging and prone intraoperative computed tomography with O-arm from L2 to L5 levels included the anteroposterior and mediolateral proximity of the psoas, aorta, inferior vena cava (IVC), and anterior iliac vessels to the vertebral body. Psoas transverse and longitudinal diameters, psoas cross-sectional area, total lumbar lordosis, and segmental lordosis were assessed. Prone position produced significant psoas lateralization, especially at more caudal levels (P < 0.001). The psoas drifted slightly anteriorly when prone, which was non-significant, but the magnitude of anterior translation significantly decreased at more caudal segments (P= 0.038) and was lowest at L5 where in fact posterior retraction was observed (P= 0.032). When prone, the IVC (P < 0.001) and right iliac vein (P= 0.005) migrated significantly anteriorly, however decreased anterior displacement was seen at more caudal levels (P < 0.001). Additionally, the IVC drifted significantly laterally at L5 (P= 0.009). Mean segmental lordosis significantly increased when prone (P < 0.001). Relative to the vertebral body, the psoas demonstrated substantial lateral mobility when prone, and posterior retraction specifically at L5. IVC and right iliac vein experienced significant anterior mobility-particularly at more cephalad levels. Prone position enhanced segmental lordosis and may be critical to optimizing sagittal restoration.

A multimodal assessment of cementless tibial baseplate fixation using radiography, radiostereometric analysis, and magnetic resonance imaging.

Fixation in cementless total knee arthroplasty is provided by osseous integration. Radiography, radiostereometric analysis (RSA), and magnetic resonance imaging (MRI) were used simultaneously to investigate fixation. Relationships between RSA-measured implant micromotions and MRI-evaluated osseous integration at the component-bone interface were assessed in 10 patients up to 6 months postoperation. Supine MRI (using multispectral imaging sequences) and RSA exams were performed to evaluate osseous integration and measure longitudinal migration, respectively. Inducible displacement was measured from standing RSA exams. Radiolucent lines were detected on conventional radiographs. Of 10 patients, 6 had fibrous membranes detected on MRI. No fluid or osteolytic interfaces were found, and no components were scored loose. Of 10 patients, 6 had radiolucent lines detected. Average maximum total point motion (MTPM) for longitudinal migration at 6 months was 0.816 mm (range 0.344-1.462 mm). Average MTPM for inducible displacement at 6 months was 1.083 mm (range 0.553-1.780 mm). Fictive points located in fibrous-classified baseplate quadrants had greater longitudinal migration than fictive points located in baseplate quadrants with normal interfaces at 2 weeks (p = 0.031), 6 weeks (p = 0.046), and 3 months (p = 0.047), and greater inducible displacements at 3 months (p = 0.011) and 6 months (p = 0.045). Greater early micromotion may be associated with the presence of fibrous membranes at the component-bone interface. Clinical significance: This multimodal imaging study contributes knowledge of the fixation of modern cementless TKA, supporting the notion that osseous integration is important for optimal implant fixation.

MRI evaluation of foraminal changes in the cervical spine with assistance of a novel compression device

Standard supine Magnetic Resonance Imaging (MRI) does not acquire images in a position where most patients with intermittent arm radiculopathy have symptoms. The aim of this study was to test the feasibility of a new compression device and to evaluate image quality and foraminal properties during a Spurling test under MRI acquisition. Ten asymptomatic individuals were included in the study (6 men and 4 women; age range 27 to 55 years). First, the subjects were positioned in the cervical compression device in a 3 T MRI scanner, and a volume T2 weighted (T2w) sequence was acquired in a relaxed supine position (3 min). Thereafter, the position and compressive forces on the patient’s neck (provocation position) were changed by maneuvering the device from the control room, with the aim to simulate a Spurling test, causing a mild foraminal compression, followed by a repeated image acquisition (3 min). A radiologist measured the blinded investigations evaluating cervical lordosis (C3–C7), foraminal area on oblique sagittal images and foraminal cross-distance in the axial plane. A total of three levels (C4–C7) were measured on the right side on each individual. Measurements were compared between the compressed and relaxed state. Reliability tests for inter- and intraclass correlation were performed. The device was feasible to use and well tolerated by all investigated individuals. Images of adequate quality was obtained in all patients. A significant increase (mean 9.4, p = 0.013) in the cervical lordosis and a decreased foraminal cross-distance (mean 32%, p < 0.001) was found, during the simulated Spurling test. The area change on oblique sagittal images did not reach a statistically significant change. The reliability tests on the quantitative measures demonstrated excellent intraobserver reliability and moderate to good interobserver reliability. Applying an individualized provocation test on the cervical spine, which simulates a Spurling test, during MRI acquisition was feasible with the novel device and provided images of satisfactory quality. MRI images acquired with and without compression showed changes in cervical lordosis and foraminal cross distance indicating the possibility of detecting changes of the foraminal properties. As a next step, the method is to be tested on symptomatic patients.

The Significance of Odontoid Incidence in Patients With Cervical Spondylotic Myelopathy.

Observational study. To analyze the cervical sagittal parameters for standing Digital radiography (DR) and supine Magnetic resonance imaging (MRI), and to further clarify the relationship between odontoid incidence (OI) and cervical spondylotic myelopathy (CSM). 52 CSM patients aged 54.46 ± 2.89years underwent both standing DR and supine MRI scans of cervical spine between November 2021 and November 2022. OI, odontoid tilt (OT), C2 slope (C2S), T1 slope (T1S), C0-2 angle, C2-7 angle (cervical lordosis [CL]), and T1S-CL were measured in both DR and MRI images using Surgimap (Version 2.3.2.1). Pearson correlation and linear regression were used to compare these parameters between the two modalities. Cervical sagittal parameters, including OI, OT, C2S, C0-2 angle, T1S, C2-7 angle (CL) and T1S-CL, showed no significant differences in the measurements between the two modalities. Based on the DR images, OI was related to OT (r = .386, P < .01), C2S (r = .505, P < .01), CL (r = -.412, P < .01), and T1S-CL (r = .320, P < .05), and OI was matched with CL (r2 = .170) and T1S-CL (r2 = .102). Based on MRI images, OI was related to OT (r = .433, P < .01), C2S (r = .516, P < .01), CL (r = -.355, P < .01), and T1S-CL (r = .271, P < .05), and OI matched with C2-7 (r2 = .126) and T1S-CL (r2 = .073). OI is an independent parameter related to cervical anatomy and its measurement is unaffected by external factors. In patients with CSM, odontoid parameters may effectively describe the sagittal alignment of the cervical spine on DR and MRI images.

Improvement of semantic segmentation through transfer learning of multi-class regions with convolutional neural networks on supine and prone breast MRI images

Semantic segmentation of breast and surrounding tissues in supine and prone breast magnetic resonance imaging (MRI) is required for various kinds of computer-assisted diagnoses for surgical applications. Variability of breast shape in supine and prone poses along with various MRI artifacts makes it difficult to determine robust breast and surrounding tissue segmentation. Therefore, we evaluated semantic segmentation with transfer learning of convolutional neural networks to create robust breast segmentation in supine breast MRI without considering supine or prone positions. Total 29 patients with T1-weighted contrast-enhanced images were collected at Asan Medical Center and two types of breast MRI were performed in the prone position and the supine position. The four classes, including lungs and heart, muscles and bones, parenchyma with cancer, and skin and fat, were manually drawn by an expert. Semantic segmentation on breast MRI scans with supine, prone, transferred from prone to supine, and pooled supine and prone MRI were trained and compared using 2D U-Net, 3D U-Net, 2D nnU-Net and 3D nnU-Net. The best performance was 2D models with transfer learning. Our results showed excellent performance and could be used for clinical purposes such as breast registration and computer-aided diagnosis.

Positional advantages of supine MRI for diagnosis prior to breast‑conserving surgery.

The present study aimed to evaluate the rate of positive surgical margins for magnetic resonance imaging (MRI) performed in the supine position prior to breast-conserving surgery (BCS). The rate of positive surgical margins and the clinicopathological factors were examined in consecutive patients with BCS who underwent preoperative MRI performed in the supine position at Sapporo Medical University Hospital (Sapporo, Japan) and related hospitals and clinics between January 2012 and December 2013. Of 1,175 eligible patients, 1,150 were included after excluding 25 patients with either bilateral breast cancer or stage IV disease. Positive margin was defined as no cancer seen on the resected margin. The primary endpoint was the rate of positive surgical margins when preoperative MRI was performed in the supine position and the secondary endpoint was identification of the factors that predict positive margins. Of the 1,150 female patients (median age, 55 years; range, 29-97 years) who underwent BCS for breast cancer following MRI performed in the supine position, 215 (18.8%) had positive margins, which is similar to the rate with MRI in the prone position, and 930 (81.2%) had negative margins. The rate of positive surgical margins in patients of the human epidermal growth factor receptor 2 (HER2) type was significantly higher than that in the non-HER2 type group (6.5 and 2.9%; χ2 P=0.0103). There was no increase in the rate of positive margins in breast cancers with a diameter of >T2. The rate of positive surgical margins following MRI performed in the supine position was 18.8%. Supine MRI appears to be suitable for informing on the extent of resection of breast cancer.

Can Supine Breast Magnetic Resonance Imaging After a Dynamic Contrast-Enhanced Breast Magnetic Resonance Imaging Provide Information for Supine Procedures?

A retrospective analysis was conducted on 75 lesions in 50 patients with pathologically proven breast cancer who underwent MRI in prone and supine positions between December 2019 and December 2020. The transverse, anteroposterior, and craniocaudal dimensions (in millimeters) of the tumor in the x -, y -, and z -axes were measured. Distances from the center of the tumor to the chest wall and the adjacent skin were measured on transverse and reformatted sagittal images. In cases where multifocal lesions were present, the transverse, anteroposterior, and craniocaudal distances between the tumor centers in the x -, y -, and z -axes were measured. Differences between measurements in supine and prone MRI were evaluated with the Mann-Whitney U and the Wilcoxon tests. P values of less than 0.05 were considered to indicate a statistically significant difference. The analysis revealed 31 MRIs with 1 and 20 with multifocal lesions. The x -axis dimension of the lesions in prone and supine positions did not significantly differ ( P = 0.198) between the 2 positions. A significant difference in the y - and z -axes dimensions was observed between the prone and supine position ( P = 0.00 for both). The distance from the tumor to the chest wall and the adjacent skin showed significant difference ( P = 0.00 for both). For multifocal lesions, the distance between the lesions showed a significant difference on the y -axis ( P = 0.00). This study showed a significant difference in the tumor size, location, and tumor-to-tumor distances due to change of patient position, from the standard prone MRI to the supine position in the operating room, resulting in distortion, spatial repositioning, and convergence of the lesions. Supine MRI may be considered in providing a less extensive surgery.

Can preoperative magnetic resonance imaging be used for sagittal kyphotic flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture?

ObjectiveThis study aimed to investigate whether preoperative magnetic resonance imaging (MRI) can be used for sagittal kyphotic (SK) flexibility assessment in patients with kyphosis secondary to symptomatic old osteoporotic thoracolumbar fracture (so-OTLF).MethodsThe authors evaluated the radiographic data of patients with kyphosis secondary to so-OTLF. All patients underwent posterior corrective fusion surgery in the hospital. Spinal sagittal parameters were measured on standing radiographs preoperatively. The regional kyphosis angle (RKA) was also measured on preoperative supine MRI and intraoperative prone radiographs on the surgical frame. The SK flexibility in patients with kyphosis secondary to so-OTLF was defined as the difference from the RKA measured on the standing radiographs to that measured on the intraoperative prone radiographs or preoperative supine MRI. The difference and the correlation between the SK flexibility measured by these two methods were compared and analyzed.ResultsThirty-seven patients were included. The RKA measured on standing radiographs, supine MRI, and intraoperative prone radiographs were 48.0°, 34.4°, and 32.0°, respectively. Compared with the RKA measured in standing position, the RKA measured on supine MRI decreased by 13.6° (95% confidence interval 11.4°–15.8°), whereas that measured on intraoperative prone radiographs decreased by 16.1° (95% confidence interval 13.7°–18.5°). A linear correlation existed between the SK flexibility measured on supine MRI and that measured on intraoperative prone radiographs, with a mean difference of 2.4° (R2 = 0.912, p < 0.001).ConclusionThe degree of regional kyphosis deformity was reduced by self-reduction of the intraoperative surgical frame. With a predictive value similar to an intraoperative prone radiograph, preoperative supine MRI can be used for SK flexibility assessment in patients with kyphosis secondary to so-OTLF. The ability to predict the intraoperative degree of regional kyphosis deformity with positioning before an operation may help with surgical planning and patient counseling regarding expectations and risks of surgery.

Comparison of sagittal spinal alignment on standing plain x-rays and supine MRI in degenerative lumbar disease.

The purpose of the present study is to examine the possible correlation between standing plain x-rays and supine magnetic resonance imaging (MRI) for evaluating spinal sagittal alignment in degenerative lumbar disease (DLD). The characteristics and images of 64 patients with DLD were reviewed retrospectively. The thoracolumbar junction kyphosis (TJK), lumbar lordosis (LL) and sacral slope (SS) were measured on lateral plain x-rays and by MRI. Inter- and intra-observer reliability was tested using intra-class correlation coefficients. The results suggested that TJK measurements obtained from MRI tended to underestimate the radiographic measures by 2°, whereas SS measurements obtained from MRI tended to overestimate the radiographic measures by 2°. The LL measurements obtained from MRI were approximately equal to the radiographic measures, and the x-ray and MRI measurements were linearly related. In conclusion, supine MRI can be directly translated into sagittal alignment angle measurements obtained from standing x-rays with an acceptable degree of accuracy. This can avoid the impaired view caused by the overlapping ilium, while reducing the patient's exposure to radiation.

Is it possible to evaluate upper and lower cervical interdependency on supine magnetic resonance imaging?

<p>There is a significant correlation between the upper and lower cervical alignments associated with a compensatory mechanism to maintain horizontal gaze. Evaluating this correlation before cervical fusion operations is essential, particularly in the upper cervical region, to prevent the occurrence of postoperative malalignment. This study was designed to investigate whether evaluating the interdependency between the upper and lower cervical alignments on neutral supine magnetic resonance imaging (MRI) or supine MRI with neck extension is possible.&nbsp;</p>. <p>This study included 36 male and 30 female volunteers without symptoms aged between 16 and 60 years. Cervical radiographic images and supine cervical spinal MRI scans were obtained twice on the neutral supine position and on the supine position with pillows placed at 5 cm high under the shoulder. Cervical lordosis (CL) (C2&ndash;7 Cobb angle), C0&ndash;2 Cobb angle, C2&ndash;7 sagittal vertical axis (C2&ndash;7SVA), T1 slope (T1S), and T1 slope minus CL (T1S-CL (C2S)) were measured from the imaging sets from each patient, including X-ray images and two MRI scans, and the main values were obtained. The mean values of the measurements from the radiographic images were compared with those obtained from MRI scans using Student&rsquo;s t-test. The agreement between the parameters (C0&ndash;2 Cobb angle, CL Cobb angle, and T1S-CL) obtained from the radiographic images and MRI scans was evaluated using Pearson correlation analysis.</p>. <p>Pearson correlation analysis revealed significant correlations between the C0&ndash;2 and C2&ndash;7 Cobb angles in standing X-ray and neutral MRI values (r = &minus;0.425 and -0.397, respectively). In plain radiography and MR studies, the T1 slope was correlated with the C2&ndash;7 angle (r = 0.4824, 0.734, and 0.702, respectively). The C2 slope values were also significantly correlated with the C0&ndash;2 Cobb angle in standing X-ray and neutral MRI images (r = 0.5595 and 0.5719, respectively). There were significant correlations between the C2 slope and C2&ndash;7 Cobb angles in all modalities (r = &minus;0.5645, &minus;0.7917, and &minus;0.8526).</p>. <p>Negative correlations between the upper and lower cervical alignments are also present in supine MRI studies, consequently in the supine position, with statistical significance. The C2 slope is an important cervical spine parameter that is significantly correlated with both the C0&ndash;2 and CL Cobb angles. The C2 slope can be used to evaluate the interdependency of the upper and lower cervical alignments.</p>.

Computational Imaging to Compensate for Soft-Tissue Deformations in Image-Guided Breast Conserving Surgery.

During breast conserving surgery (BCS), magnetic resonance (MR) images aligned to accurately display intraoperative lesion locations can offer improved understanding of tumor extent and position relative to breast anatomy. Unfortunately, even under consistent supine conditions, soft tissue deformation compromises image-to-physical alignment and results in positional errors. A finite element inverse modeling technique has been developed to nonrigidly register preoperative supine MR imaging data to the surgical scene for improved localization accuracy during surgery. Registration is driven using sparse data compatible with acquisition during BCS, including corresponding surface fiducials, sparse chest wall contours, and the intra-fiducial skin surface. Deformation predictions were evaluated at surface fiducial locations and subsurface tissue features that were expertly identified and tracked. Among n = 7 different human subjects, an average of 22 ± 3 distributed subsurface targets were analyzed in each breast volume. The average target registration error (TRE) decreased significantly when comparing rigid registration to this nonrigid approach (10.4 ± 2.3 mm vs 6.3 ± 1.4 mm TRE, respectively). When including a single subsurface feature as additional input data, the TRE significantly improved further (4.2 ± 1.0 mm TRE), and in a region of interest within 15 mm of a mock biopsy clip TRE was 3.9 ± 0.9 mm. These results demonstrate accurate breast deformation estimates based on sparse-data-driven model predictions. The data suggest that a computational imaging approach can account for image-to-surgery shape changes to enhance surgical guidance during BCS.

Do thoracoabdominal organ boundaries differ between males and females? Implications for body armour coverage and design

To optimise fit and protection of body armour systems, knowledge of the location of thoracoabdominal organ boundaries is required. The aims of this study were (i) determine the effect of sex on essential and desirable thoracoabdominal organ boundaries, and (ii) compare essential thoracoabdominal organ boundaries with small and large hard ballistic plate sizes from the National Institute of Justice (NIJ) and determine if coverage requirements differ between sexes. 33 males and 33 females underwent supine magnetic resonance imaging of their thoracoabdominal organs. Male participants on average displayed more laterally and inferiorly positioned essential and desirable organ boundaries than females. Based on NIJ plate sizes, insufficient coverage of essential organs was identified for male and female participants. A greater range of body armour sizes and designs that better cater to the diverse anatomy of soldier populations is warranted, but must be considered in the context of ergonomic and performance implications.

Lumbar plexus safe working zones with lateral lumbar interbody fusion: a systematic review and meta-analysis.

Significant risk of injury to the lumbar plexus and its departing motor and sensory nerves exists with lateral lumbar interbody fusion (LLIF). Several cadaveric and imaging studies have investigated the lumbar plexus position with respect to the vertebral body anteroposterior plane. To date, no systematic review and meta-analysis of the lumbar plexus safe working zones for LLIF has been performed. This systematic review was conducted according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Relevant studies reporting on the position of the lumbar plexus with relation to the vertebral body in the anteroposterior plane were identified from a PubMed database query. Quantitative analysis was performed using Welch's t test. Eighteen studies were included, encompassing 1005 subjects and 2472 intervertebral levels. Eleven studies used supine magnetic resonance imaging (MRI) with in vivo subjects. Seven studies used cadavers, five of which performed dissection in the left lateral decubitus position. A significant correlation (p < 0.001) existed between anterior lumbar plexus displacement and evaluation with in vivo MRI at all levels between L1-L5 compared with cadaveric measurement. Supine position was also associated with significant (p < 0.001) anterior shift of the lumbar plexus at all levels between L1-L5. This is the first comprehensive systematic review and meta-analysis of the lumbar neural components and safe working zones for LLIF. Our analysis suggests that the lumbar plexus is significantly displaced ventrally with the supine compared to lateral decubitus position, and that MRI may overestimate ventral encroachment of lumbar plexus.