Supine MRI Research Articles

High intensity in interspinous ligaments: a diagnostic sign of lumbar instability and back pain for degenerative lumbar spondylolisthesis

BackgroundTo investigate the clinical significance of high intensity signals in interspinous ligaments at the affected segment in degenerative lumbar spondylolisthesis (DLS), as well as to determine the most effective diagnostic modalities for evaluating segmental instability.MethodsThis study reviewed a consecutive series of patients with L4/5 DLS between July 2023 and December 2023. The enrolled patients were divided into two groups based on the presence or absence of high-intensity signals in interspinous ligaments: the higher group (Group H), and the non-higher group (Group NH). Translational and angular motion was determined using flexion and extension (FE) radiographs or a sitting lumbar lateral radiograph with a supine sagittal MR image (combined, S-MR). The five-repetition sit-to-stand test (5R-STS) was employed to evaluate patients’ objective functional impairment (OFI).ResultsOverall, 73 patients were enrolled in this study, and there were 22 (30.1%) patients in group H and 51(69.9%) patients in group NH, with an average age of 60.3 ± 8.1 years. The patients in Group H exhibited significantly longer 5R-STS times and serious OFI compared to those in Group NH. Compared to Group NH, Group H exhibited significantly higher SP in the sitting position (21.8% vs 16.7%; P < 0.001*), while no significant differences were observed in the upright, flexion, extension, and supine MRI positions (all P values > 0.05). In Group H, “instability” was recognized in 77.3% of patients using S-MR versus 40.9% patients using FE (P < 0.001); While in Group NH, no significant difference was observed in the incidence of “instability” between FE and s-MR (37.3% vs. 31.4%, P = 0.53). Overall, a significantly higher incidence of instability was found in Group H compared to Group NH (77.3% vs .37.3%, P < 0 .001*).ConclusionsDLS with a high intensity within the interspinous ligaments is a distinct subgroup associated with segmental instability, the combination of 5R-STS and S-MR should be regarded as the most clinically relevant approach for assessing OFI and lumbar instability.

Dynamic Instability Is Underestimated on Standing Flexion-Extension Films When Compared With Prone CT Imaging.

Single center retrospective cohort study. We performed a retrospective study evaluating the incidence and degree of L4-5 anterior spondylolisthesis in patients with standard supine MRI, standing flexion-extension radiographs, and prone CT. We hypothesize that prone CT imaging will provide greater sensitivity for instability compared with conventional flexion extension or supine positions. Dynamic lumbar instability evaluated by flexion-extension radiographs may underestimate the degree of lumbar spondylolisthesis. Despite efforts to characterize dynamic instability, significant variability remains in current guidelines regarding the most appropriate imaging modalities to adequately evaluate instability. We assessed single-level (L4-5) anterolisthesis between 2014 and 2022 with standing lateral conventional radiographs (CR), flexion-extension images, prone CT images (CT), or supine MRI images (MRI). We identified 102 patients with L4-5 anterolisthesis. The average translation (±SD) measured were 4.9±2.2mm (CR), 2.5±2.6mm (CT), and 3.7±2.6mm (MRI) (P<0.001). The mean difference in anterolisthesis among imaging modalities was 2.7±1.8mm between CR and CT (P<0.001), 1.8±1.4mm between CR and MRI (P<0.001), and 1.6±1.4mm between CT and MRI (P=0.252). Ninety-two of 102 patients (90.2%) showed greater anterolisthesis on CR compared with CT, 72 of 102 (70.6%) comparing CR to MRI, and 27 of 102 (26.5%) comparing CT to MRI. We found that 17.6% of patients exhibited ≥3mm anterior translation comparing CR with MRI, whereas 38.2% of patients were identified comparing CR with CT imaging (χ2 test P=0.0009, post hoc Fisher exact test P=0.0006 between CR and CT). Only 5.9% of patients had comparable degrees of instability between flexion-standing. Prone CT imaging revealed the greatest degree of single L4-5 segmental instability compared with flexion-extension radiographs.

An Open Source 16-Channel Breast Array for Prone and Supine MRI

An Open Source 16-Channel Breast Array for Prone and Supine MRI

Evaluation of the intramammary distribution of breast lesions detected by MRI but not conventional second-look B-mode ultrasound using an MRI/ultrasound fusion technique

The objective of this study was to evaluate the intramammary distribution of MRI-detected mass and focus lesions that were difficult to identify with conventional B-mode ultrasound (US) alone. Consecutive patients with lesions detected with MRI but not second-look conventional B-mode US were enrolled between May 2015 and June 2023. Following an additional supine MRI examination, we performed third-look US using real-time virtual sonography (RVS), an MRI/US image fusion technique. We divided the distribution of MRI-detected mammary gland lesions as follows: center of the mammary gland versus other (superficial fascia, deep fascia, and atrophic mammary gland). We were able to detect 27 (84%) of 32 MRI-detected lesions using third-look US with RVS. Of these 27 lesions, 5 (19%) were in the center of the mammary gland and 22 (81%) were located in other areas. We were able to biopsy all 27 lesions; 8 (30%) were malignant and 19 (70%) were benign. Histopathologically, three malignant lesions were invasive ductal carcinoma (IDC; luminal A), one was IDC (luminal B), and four were ductal carcinoma in situ (low-grade). Malignant lesions were found in all areas. During this study period, 132 MRI-detected lesions were identified and 43 (33%) were located in the center of the mammary gland and 87 (64%) were in other areas. Also, we were able to detect 105 of 137 MRI-detected lesions by second-look conventional-B mode US and 38 (36%) were located in the center of the mammary gland and 67 (64%) were in other areas. In this study, 81% of the lesions identified using third-look US with RVS and 64% lesions detected by second-look conventional-B mode US were located outside the center of the mammary gland. We consider that adequate attention should be paid to the whole mammary gland when we perform third-look US using MRI/US fusion technique.

Abstract PO4-07-08: Impact of an MRI/US fusion imaging for preoperative planning using non-wire localization technique in breast conserving surgery in patients with non-mass enhancement on MRI. A prospective multicenter study

Abstract [Background] Preoperative breast MRI is used to evaluate for additional and extent disease for newly diagnosed breast cancer patients with dense breasts. The potential benefit of preoperative MRI is still being controversial. However, when breast conserving surgery (BCS) is considered for non-mass enhancement (NME) on MRI, the precise image-guided localization is required. Although breast ultrasound (US) plays an adjunctive role in evaluation of MRI findings in preoperative planning for BCS, NME is less likely than a mass or focus to have a US correlate. Furthermore, the presence of NME increases the re-operation rate in BCS because of the difficulty in evaluating the tumor margin. An MRI/US fusion imaging has recently been developed that uses either real-time virtual sonography TM (RVS) or volume navigation TM (Vnav), and can overlay an US with the MRI image of the same site in real time by using magnetic position tracking system. The purpose of this prospective multicenter study was to evaluate the effect of MRI/US fusion imaging for preoperative planning using non-wire localization technique in BCS in patients with NME. [Methods] In 3 Japanese hospital, 13 patients who had lesions with NME that exceeded the US hypoechoic area were enrolled in this study from 2019 to 2022. Written informed consent was acquired, and then an additional supine MRI using a body surface coil was performed. During preoperative planning before BCS, RVS/Vnav was used to determine the NME enhancing area and to mark the area on the skin. Tissue markers were inserted under US at a location assessed by RVS/Vnav as the edge of extent of NME. We analyzed both the surgical margin positivity rate and the reoperation rate. [Results] The preoperative diagnosis by core needle biopsy were 6 DCIS and 7 invasive ductal carcinoma. NME distribution types were 7 segmental, 3 focal, 2 linear 4 and 1 regional. The median diameters of the NME and hypo-echoic lesions were 31 mm (range: 18–39 mm) and 16 mm (range: 9–32 mm), respectively (p = 0.0005). After confirming the localization of the tissue marker with intraoperative US, 12 lumpectomy and 1 quadrantectomy were conducted. The median specimen weight was 63g (range: 54-105g). In the final pathologic diagnosis of excised specimens were 5 DCIS and 8 IDC. In 8 cases (62%), the pathologic diameter was larger than the US diameter. All surgical margins were negative. None of the patients required additional resection. [Conclusions] The findings of study suggest that preoperative planning using non-wire localization technique under MRI/US fusion imaging for BCS in patients with NME could improve both a surgical margin positive rate and a reoperation rate. Citation Format: Shogo Nakano, Manabu Futamura, Keitaro Kamei, Takayoshi Uematsu, Miwa Yoshida, Sadako Akashi-Tanaka, Junta Sakakibara, Ichiro Isomoto, Hiroko Satake, Maiko Takahashi, Minami Hatono, Junko Araki. Impact of an MRI/US fusion imaging for preoperative planning using non-wire localization technique in breast conserving surgery in patients with non-mass enhancement on MRI. A prospective multicenter study [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 PO4-07-08.

Comparative Analysis of Vascular Structures in OLIF51 and the Lateral Corridor Approach under Supine MRI and Intraoperative Enhanced CT in the Lateral Decubitus Position.

Background and Objectives: As the oblique lateral interbody fusion at L5/S1 (OLIF51) and the lateral corridor approach (LCA) have gained popularity, an understanding of the precise vascular structure at the L5/S1 level is indispensable. The objectives of this study were to investigate the vascular anatomy at the L5/S1 level, and to compare the movement of vascular tissue between the supine and lateral decubitus positions using intraoperative enhanced CT and MRI. Materials and Methods: A total of 43 patients who underwent either OLIF51 or LCA were investigated with an average age at surgery of 60.4 (37-80) years old. The preoperative MRI was taken to observe the axial and sagittal anatomy of the vascular position under the supine position. The intraoperative vein-enhanced CT was taken just before incision in the right decubitus position, and compared to supine MRI anatomy. Iliolumbar vein appearance and its types were also classified. Results: The average vascular window allowed for OLIF51 was 22.8 mm and 34.1 mm at either the L5 caudal endplate level or the S1 cephalad endplate level, respectively. The LCA was 14.2 mm and 12.6 mm at either level, respectively. The left common iliac vein moved 3.8 mm and 6.9 mm to the right direction at either level from supine to the right decubitus position, respectively. The bifurcation moved 6.3 mm to the caudal direction from supine to right decubitus. The iliolumbar vein was located at 31 mm laterally from the midline, and the MRI detection rate was 52%. Conclusions: The precise measurement of vascular anatomy indicated that the OLIF51 approach was the standard minimally invasive anterior approach for the L5/S1 disc level compared to LCA; however, there were many variations in quantitative anatomy as well as significant vascular movements between the supine and right decubitus positions. In the clinical setting of OLIF51 and LCA surgeries, careful preoperative evaluation and intraoperative 3D imaging are recommended for safe and accurate surgery.

Evaluation of Image Quality of Motion-Corrected Supine Breast MRI.

Breast MRI is the most performant modality for breast cancer diagnosis and could be widespread in the future. The gold standard breast MRI is performed in the prone position, but comfort and correlation with surgery or biopsy positioning can be problematic, while supine MRI could be an interesting alternative. In this work, we evaluated the image quality of T2-weighted supine breast MRI in healthy volunteers after online correction of respiratory motion artifacts compared to standard vendor's reconstruction and to standard prone MRI. T2-weighted images were acquired in the prone and free-breathing supine position in 10 volunteers. Two types of reconstructions were evaluated for supine acquisitions: the standard vendor's reconstruction and an online version of a nonrigid motion correction technique (generalized reconstruction by inversion of coupled system). Image quality criteria, including overall quality, sharpness, uniformity, and different types of artifacts, were assessed and scored by 2 radiologists in a randomized fashion. Interobserver agreement was verified by Weighted Cohen's Kappa calculation and a comparison between the different acquisitions was made by Wilcoxon signed-rank test. Generalized Reconstruction by Inversion of Coupled Systems (GRICS) reconstruction method significantly increased image quality in comparison to the standard reconstruction of supine acquisition. It allows a comparable quality, slightly lower than the gold standard prone MRI in T2-weighted images but it needs to be assessed with more patients and with target lesions before it can be used in clinical practice.

P39. Combining flexion lateral radiographs with a supine MRI is superior to a combination of flexion and extension lateral radiographs at detecting vertebral instability in patients with spondylolisthesis

P39. Combining flexion lateral radiographs with a supine MRI is superior to a combination of flexion and extension lateral radiographs at detecting vertebral instability in patients with spondylolisthesis

Comparison of Cobb angle measurements for scoliosis assessment using different imaging modalities: a systematic review.

To report accuracy, repeatability, and agreement of Cobb angle measurements on radiographs and/or stereo-radiographs (EOS) compared against one another or against other imaging modalities. This review follows Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. A literature search was conducted on 21 July 2021 using Medline, Embase, and Cochrane. Two researchers independently performed title/abstract/full-text screening and data extraction. Studies were eligible if they reported Cobb angles, and/or their repeatability and agreement, measured on radiographs and/or EOS compared against one another or against other imaging modalities. Of the 2993 records identified, 845 were duplicates and 2212 were excluded during title/abstract/full-text screening. Two more relevant studies were identified from references of eligible studies, leaving 14 studies for inclusion. Two studies compared Cobb angles from EOS vs CT, while 12 compared radiographs vs other imaging modalities: EOS, CT, MRI, digital fluoroscopy, or dual-energy x-ray absorptiometry. Angles from standing radiographs tended to be higher than those from supine MRI and CT, and angles from standing EOS tended to be higher than those from supine or prone CT. Correlations across modalities were strong (R = 0.78-0.97). Inter-observer agreement was excellent for all studies (ICC = 0.77-1.00), except one (ICC = 0.13 radiographs and ICC = 0.68 for MRI). Differences of up to 11º were found when comparing Cobb angles across combinations of imaging modalities and patient positions. It is not possible, however, to determine whether the differences observed are due to the change of modality, position, or both. Therefore, clinicians should be careful when utilizing the thresholds for standing radiographs across other modalities and positions for diagnosis and assessment of scoliosis.

Comparison between conventional MRI and weight-bearing positional MRI reveals important differences in radiological measurements of the patellofemoral joint.

To compare radiological measurements of the patellofemoral joint (PFJ) morphology and measurement reproducibility across the following scanning modalities: (a) 3 T supine MRI, (b) 0.25 T supine MRI and (c) standing 0.25 T MRI. Forty patients referred to MRI of the knee were scanned by high field 3 T MRI in supine position and low field 0.25 T positional (pMRI) in supine and standing positions. Radiological measurements for assessment of femoral trochlear morphology, patellar tracking, patellar height and knee flexion angle were compared across scanning situations by one-way repeated-measures ANOVA. Measurement reliability and agreement were assessed by calculation of ICC, SEM and MDC. Patellar tracking differed across scanning situations, particularly between 3.0 T supine and 0.25 T standing position. Mean differences are the following: patella bisect offset (PBO): 9.6%, p ≤ 0.001; patellar tilt angle (PTA): 3.1°, p ≤ 0.001; tibial tuberosity-trochlear groove distance (TT-TG): 2.7 mm, p ≤ 0.001). Measurements revealed slight knee joint flexion in supine and slight hyperextension in the standing position (MD: 9.3°, P ≤ 0.001), likely related to the observed differences in patellar tracking. Reproducibility was comparable across MRI field strengths. In general, PBO, PTA and TT-TG were the most robust measurements in terms of reproducibility and agreement across scanning situations (ICC range: 0.85-0.94). Significant differences in important patellofemoral morphology measurements were observed between supine and standing MRI scanning positions. These were unlikely due to physiological factors such as changes in joint loading but rather induced by slight differences in knee flexion angle. This emphasises the need to standardise knee positioning during scanning, particularly for weight-bearing positional MRI before clinical use.

Reliability of segmental instability and spinopelvic alignment in athletes with isthmic spondylolisthesis in functional MRI

Problem Statement: In athletes with spondylolisthesis, segmental instability and impaired spinopelvic alignment are considered as clinically relevant. Functional MRI in supine and upright position enables a load-dependent acquisition, but neither the reposition effect nor the difference in the extent of inter-position-related differences has been investigated for their reliability. This study evaluates the intra- and inter-positional test-retest reliability of segmental instability and spinopelvic alignment in athletes with low-grade isthmic lumbar spondylolisthesis using supine and upright MRI. Methods: 22 athletes with spondylolisthesis were analyzed in a test-retest design. Parameters quantifying segmental instability (anterior translation [mm], segmental hinging [°], disc height [mm]) and spinopelvic alignment (lordosis angle [°], Sacral slope [°]),) were assessed in supine (0°) and upright (82°) MRI position. Intra-positional changes and differences of inter-positional changes were analyzed using absolute and relative indicators of reliability (amongst other intraclass-correlation-coefficient (ICC 2.1) and standard error of measurements (SEM%)). Results: Intra-positional changes showed high correlations and low absolute changes in both positions (ICC: 0.91-0.98; SEM%: 1-7%). Differences of inter-positional changes presented poor-to-moderate correlations and higher absolute changes (ICC: 0.34-0.74; SEM%: 33-60%). Discussion: Intra-positional changes can be determined reliably among all assessed outcomes. Inter-position-related changes of segmental instability indicate a reduced reproducibility in the current population. Conclusion: Functional MRI can be considered a valuable diagnostic tool for evaluating segmental instability and spinopelvic alignment in spondylolisthesis patients.

Comparison of MRI and bolster hyperextension radiography in determining the flexibility of thoracic curves in Scheuermann kyphosis: a retrospective cross-sectional study

Background: The flexibility of the thoracic curve is important for the preoperative planning for patients with Scheuermann kyphosis (SK), and a lateral bolster hyperextension radiograph (HE) is the standard available method for this purpose. In this study, the authors aimed to evaluate how the flexibility of the thoracic curve in classic SK patients correlates between supine MRI and HE radiography. Methods: In a retrospective cross-sectional study, 38 SK patients who underwent surgical correction were included. Cobb angles were measured on three different images: lateral standing radiographs (EOS), lateral supine bolster HE radiography, and T2-weighted sagittal MRI. The mean differences between the Cobb angles measured on standing radiographs (EOS) and supine modalities (HE and MRI) was considered as the flexibility of the thoracic curve. Measurements were done two times by two orthopaedic spine surgeons, and acceptable intraobserver and interobserver reliability was observed using an intraclass correlation coefficient test. Results: The study population included 23 (60.5%) male patients and 15 (39.5%) female patients with a mean age of 23.4±8.8 yr (range 13 to 48). The mean flexibility of the thoracic curve was 31±10.9 degrees (40.5%) on supine MRIs and 36.1±11.5 degrees (47.25%) on bolster HE radiographs. A significant correlation was observed between the mean flexibility of the thoracic curve on MRI and HE radiographs (r=0.601, P&lt;0.001). Conclusions: Supine MRI can be regarded as a promising alternative to bolster HE radiography in determining the flexibility of thoracic curves in patients with classic SK. Level of Evidence: Level III

Fusion biopsy or real time virtual sonography (RVS) technique – the first experience in verification of hypervascular breast lesions under combined US/MR control

One of the actual problems of oncology is the early diagnosis of breast cancer. However, there are some difficulties not only in diagnostic but also in the verification of lesions. Image-guided cor-biopsy nowadays became the gold standard for verification of non-palpable breast lesions. The main issue is to choose the method of visualization. According to up-to-date recommendations, there is no universal method with all requirements (high visualization quality, convenience, and accessibility for biopsy). Fusion-biopsy or virtual real-time sonography can combine MRI diagnostic potential and facility of USAim: to leverage the technique of fusion biopsy under combined ultrasound/MR control for verification of breast lesions identified only on MRI and occult on MG and US.Methods. 30 high-risk patients, who had pathological breast lesions detected by diagnostic CE-MRI, classified as BI-RADS 4, 5 yet occult on the other visualization methods were enrolled in the study. All patients underwent supine MRI prebiopsy examination, real-time virtual sonography of the lesions, image-guided biopsy or excisional biopsy, histopathologic examination.Results. The breast fusion-biopsy method was developed based on up-to-date scientific publications and optimized for the technical equipment of N.N. Petrov National Medicine Research Center of Oncology. According to the designed protocol of examination, there were the following steps: interpretation of breast CE-MRI in the standard prone position for breast lesion detection, prebiopsy CE-MRI performed in the supine position, real-time virtual sonography for comparison of breast MRI and US, histopathologic examination.Conclusion. Being one of the perspectives methodic of morphological verification Fusion-biopsy might become a more common procedure in breast lesions diagnostics. The simplicity of US-guided biopsy and high MRI breast diagnostic sensitivity are combined in fusion-biopsy technology.

A comparative study of supine traction, supine side-bending radiographs, and supine MRI to determine coronal flexibility in degenerative lumbar scoliosis patients.

The purpose of this study was to compare curve correction in degenerative lumbar scoliosis using supine traction radiographs, supine side-bending radiographs, and supine MRI. A prospective analysis of Cobb angles from patients diagnosed with degenerative lumbar scoliosis who underwent supine traction radiography (TR), side-bending radiography (SB), and supine MRI. The Cobb angles at thoracic (T), thoracolumbar/lumbar (TL/L), and lumbosacral (LS) levels were measured, and the curvecorrection in percentages compared with standing AP radiography was calculated as corrective flexibility. Differences in curve correction were analyzed. In total, 33 patients with an age range of 50-80years were eligible for inclusion. Traction radiography provided the greatest accuracy in curve correction, with a significant difference from side-bending radiography and supine MRI in T, TL/L, and LS levels (P < 0.001). The difference between side-bending radiography and supine MRI in TL/L and LS levels wasnot significant (P = 0.721, P = 0.654, respectively). A moderate correlation was found between the corrective flexibility of TR and SB at the T level (0.563, P = 0.001), a strong correlation was observed between the corrective flexibility of TR and SB at the TL/L level (0.709, P < 0.001), and at the TL/L level, a moderate correlation was identified between TR and supine MRI corrective flexibility (0.425, P = 0.014). Traction radiographs significantly outperformed side-bending radiographs and supine MRI in terms of access curve flexibility in degenerative lumbar scoliosis.

Correlation Between Obliquity of Exiting Nerve Root on Lateral Sagittal MRI Images and Degenerative Spondylolisthesis.

MRI has become the investigation of choice for patients of low back pain with radiculopathy. However, MRI does not consistently detect spondylolisthesis. In far lateral sagittalT2 MRI images, exiting nerve roots are seen descending vertically. We observed that the obliquity of these descending nerve roots may be related to spondylolisthesis. Aim of this study is to evaluate the correlation between obliquity of exiting nerve root on MRI and lumbar instability on dynamic radiographs. We retrospectively studied 248 patients who underwent discectomy or laminectomy and stabilization for degenerative lumbar disease at our institute from January 2017 to February 2020. For objectively measuring the obliquity of the exiting nerve root, we described an angle between the vertebra and exiting nerve root on far lateral T2 MRI images. We measured the exiting root angle and studied its correlation with degenerative spondylolisthesis on dynamic X-rays. Out of 108 patients having spondylolisthesis, 106 (98.15%) had an angle of obliquity of the exiting nerve root as >105° and only two (1.85%) had an angleof <105°. Among 140 patients without spondylolisthesis, 137 (97. 86%) had an angle of obliquity of <105°and only three (2.14%) had an angle of >105°. Statistical parameters for our test of "angle of obliquity for the exiting nerve root in spondylolisthesis"are as follows: sensitivity of the test- 98.14%, specificity of the test- 97.85%. Obliquity of the exiting nerve root is a very easy to detect. It has avery high sensitivity and very high specificity for detecting spondylolisthesis on supine MRI.

A pilot multi-institutional study to evaluate the accuracy of a supine MRI based guidance system, the Breast Cancer Locator™, in patients with palpable breast cancer

BackgroundEvaluate whether the Breast Cancer Locator™ (BCL), a novel guidance system based on supine MRI images, can be safely and effectively deployed by several surgeons at multiple sites. MethodsPatients with palpable breast cancer underwent supine MRI at their local institution. A three dimensional (3D) digital image of the tumor in the breast was derived from supine MRI images and used to generate 1) an interactive 3D virtual image of the tumor in the breast (Visualizer) and 2) a plastic bra-like form that allowed the surgeon to place a central wire and bracketing wires in the breast (BCL). The primary objective was to determine the proportion of patients who had the central localization wire deployed within the cancer on specimen mammogram. ResultsFourteen patients were enrolled at 4 different sites by 6 surgeons. BCLs were successfully manufactured for all patients. The central wire was deployed within the tumor on specimen mammogram in 12 of the 13 patients who had a central wire placed (92%). The cancer was excised with negative margins in 14/14 cases (100%). No adverse events occurred. ConclusionsSupine MRI image acquisition was accomplished successfully across multiple sites. Multiple surgeons utilized the BCL system to localize cancers accurately and safely.

An MRI-based Study to Investigate If the Patella is Truly Centred between the Femoral Condyles in the Coronal Plane

BackgroundAn AP knee radiograph is considered adequate if the patella is centred between the femoral condyles. Our previous studies demonstrated a tendency for lateral patellar deviation on an AP view orthogonal to the posterior femoral condyles. However, findings were based on cadaveric samples limited by the lack of soft tissue effects on patellar positioning.Materials and methodsAfter excluding those with deformity or damage to osseous or ligamentous structures, 106 knee MRI scans were randomly selected. Patellar centring was calculated as a percentage of total distal femoral intercondylar width and represented how lateral the centre of the patella is located with respect to the midpoint of the femoral condyles. Multiple regression analysis was performed to determine the relationship between patellar centring and age, gender, anatomic lateral distal femoral angle (aLDFA), medial proximal tibial angle (MPTA) and tibial tuberosity to trochlear groove (TT-TG) distance.ResultsThere were 35 males and 71 females included in the study with a mean age of 29 ± 14 years. Mean patellar centring was 8 ± 4%. There was a statistically significant correlation between TT-TG distance and positive (lateral) patellar centring (standardised β = 0.36, p <0.01). There were no associations between aLDFA and MPTA with patellar centring.ConclusionThis study demonstrates that the patella is rarely perfectly centred and is usually positioned slightly laterally within the femoral condyles in an AP view orthogonal to the posterior aspect of the femoral condyles. The use of supine MRI scans makes this data relevant to a patient on the operating room table.How to cite this articleShah NS, Kyriakedes JC, Liu RW. An MRI-based Study to Investigate If the Patella is Truly Centred between the Femoral Condyles in the Coronal Plane. Strategies Trauma Limb Reconstr 2022;17(2):63–67.

Intermodal Detection of Lumbar Instability in Degenerative Spondylolisthesis is Superior toFunctional Radiographs.

PurposeIn this study, we compare different imaging modalities to find the most sensitive and efficient way of detecting instability in lumbar spondylolisthesis.MethodsPatients presenting with spondylolisthesis from June 01, 2018 to May 31, 2020 with functional radiographs and either CT scans or MRI images were included in our single-center retrospective cohort study. The amount of translation, in millimeters, was measured on supine MRI images, CT scans, and radiographs of inclination while sitting, standing, or prone and reclination while standing using the Meyerding technique. The amount of translation was compared among the different modalities.ResultsA total of 113 patients with spondylolisthesis on 125 vertebral levels were included in this study. The mean patient age was 73.52 ± 12.59 years; 69 (60.5%) patients were females. The most affected level was L4/5 (62.4%), followed by L3/4 (16%) and L5/S1 (13.6%). The average translations measured on supine CT were 4.13 ± 5.93 mm and 4.42 ± 3.49 mm on MRI (p = 0.3 for the difference between MRI and CT). The difference of inclination while sitting radiograph to slice imaging was 3.37 ± 3.64 mm (p < 0.0001), inclination while standing to slice imaging was 2.67 ± 3.03 mm (p < 0.0001), reclination while standing to slice imaging was 1.6 ± 3.15 mm (p = 0.03), and prone to slice imaging was 2.19 ± 3.02 mm (p = 0.03).ConclusionWe found that a single radiograph in either inclination, reclination, or prone position compared to a CT scan or an MRI image in supine position can detect instability in spondylolisthesis more efficiently than comparison of functional radiographs in any position.

Reliability of reporting differences in degenerative MRI findings of the lumbar spine from the supine to the upright position

ObjectiveTo determine the inter-rater reliability of identifying differences and types of differences in lumbar degenerative findings comparing supine and upright MRI.Materials and methodsFifty-nine participants, low back pain patients (LBP) with or without leg pain and no-LBP individuals were consecutively enrolled to receive supine and upright MRI of the lumbar spine. Three raters independently evaluated the MRIs for degenerative spinal pathologies and compared for differences. Presence/absence of degenerative findings were recorded for all supine and upright images, and then differences from the supine to the upright positions were classified into no-change, appeared, disappeared, worsened, or improved at each individual disc level. Reliability and agreement were calculated using Gwet’s agreement coefficients (AC1 or AC2) and absolute agreement.ResultsInter-rater reliability of evaluating differences in eight degenerative lumbar findings comparing the supine and upright MRI position, ranged from 0.929 to 0.996 according to Gwet’s agreement coefficients (AC2). The total number of positive MRI findings in the supine position ranged from 270 to 453, with an average of 366 per rater. Observed differences from supine to upright MRI ranged from 18 to 80, with an average of 56 per rater.ConclusionInter-rater reliability was found overall acceptable for classification of differences in eight types of degenerative pathology observed with supine and upright MRI of the lumbar spine. Results were primarily driven by high numbers and high reliability of rating negative findings, whereas agreement regarding positive findings and positive positional differences was lower.

Anatomical positional changes in the lateral lumbar interbody fusion.

ALIFs and LLIFs are now becoming more utilized for adult spinal disease. As technologies advance, so do surgical techniques, with surgeons now modifying traditional supine-ALIF and lateral-LLIF to lateral-ALIF and prone-LLIF approaches to allow for more efficient surgeries. The objective of this study is to characterize the anatomical changes in the surgical corridor that occur with changes in patient positioning. MRIs of ten healthy volunteers were evaluated in five positions: supine, prone with hips flexed, prone with hips extended, lateral with hips flexed, and lateral with hips extended. All lateral scans were in the left lateral decubitus position. The anatomical changes of the psoas muscles, inferior vena cava, aorta, iliac vessels were assessed with relation to fixed landmarks on the disc spaces from L1 to S1. The most anteriorly elongated ipsilateral to approach psoas when compared to supine was seen in lateral-flexed position (-5.82mm, p < 0.001), followed by lateral-extended (-2.23mm, p < 0.001), then prone-flexed (-1.40mm, p = 0.014), and finally supine and prone-extended (-0.21mm, p = 0.643). The most laterally extending or "thickest" psoas was seen in prone-flexed (-1.40mm, p = 0.004) and prone-extended (-1.17mm, p = 0.002). The psoas was "thinnest" in lateral-extended (2.03mm, p < 0.001) followed by lateral-flexed (1.11mm, p = 0.239). The contralateral psoas did not move as anteriorly as the ipsilateral. 3D volumetric analysis showed that the greatest changes in the psoas occur at its proximal and distal poles near T12-L1 and L4-S1. In lateral-flexed compared to prone-extended, the IVC moves medially to the left (p < 0.001). The aorta moves laterally to the left (p = 0.005). The venous structures appeared more full and open in the lateral positions and flattened in the supine and prone positions. The arteries remain in full calibre. The MRI anatomical evaluation shows that the psoas, and therefore lumbar plexus, and vasculature move significantly with changes in positioning. This is important for preoperative planning for proper intraoperative execution from preoperative supine MRI. Understanding that the psoas and vessels move the most anteriorly in the lateral-flexed position and to a least degree in the prone-extended is essential for safe and efficient utilization of techniques such as the traditional LLIF, traditional ALIF, prone-LLIF.