Wnt/β‐catenin signaling of cartilage canal and osteochondral junction chondrocytes and full thickness cartilage in early equine osteochondrosis

The objective of this study was to elucidate gene and protein expression of Wnt signaling molecules in chondrocytes of foals having early osteochondrosis (OC) versus normal controls. The hypothesis was that increased expression of components of Wnt signaling pathway in osteochondral junction (OCJ) and cartilage canal (CC) chondrocytes would be found in early OC when compared to controls. Paraffin‐embedded osteochondral samples (7 OC, 8 normal) and cDNA from whole cartilage (7 OC, 10 normal) and chondrocytes surrounding cartilage canals and osteochondral junctions captured with laser capture microdissection (4 OC, 6 normal) were obtained from femoropatellar joints of 17 immature horses. Equine‐specific Wnt signaling molecule mRNA expression levels were evaluated by two‐step real‐time qPCR. Spatial tissue protein expression of β‐catenin, Wnt‐11, Wnt‐4, and Dkk‐1 was determined by immunohistochemistry. There was significantly decreased Wnt‐11 and increased β‐catenin, Wnt‐5b, Dkk‐1, Lrp6, Wif‐1, Axin1, and SC‐PEP gene expression in early OC cartilage canal chondrocytes compared to controls. There was also significantly increased β‐catenin gene expression in early OC osteochondral junction chondrocytes compared to controls. Based on this study, abundant gene expression differences in OC chondrocytes surrounding cartilage canals suggest pathways associated with catabolism and inhibition of chondrocyte maturation are targeted in early OC pathogenesis. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1433–1438, 2015.     

Histological confirmation and biological significance of cartilage canals demonstrated using high field MRI in swine at predilection sites of osteochondrosis

Cartilage canal vessels in epiphyseal cartilage have a pivotal role in the pathogenesis of osteochondrosis/osteochondritis dissecans. The present study aimed to validate high field magnetic resonance imaging (MRI) methods to visualize these vessels in young pigs. Osteochondral samples from the distal femur and distal humerus (predilection sites of osteochondrosis) of piglets were imaged post‐mortem: (1) using susceptibility‐weighted imaging (SWI) in an MRI scanner, followed by histological evaluation; and (2) after barium perfusion using µCT, followed by clearing techniques. In addition, both stifle joints of a 25‐day‐old piglet were imaged in vivo using SWI and gadolinium enhanced T1‐weighted MRI, after which distal femoral samples were harvested and evaluated using µCT and histology. Histological sections were compared to corresponding MRI slices, and three‐dimensional visualizations of vessels identified using MRI were compared to those obtained using µCT and to the cleared specimens. Vessels contained in cartilage canals were identified using MRI, both ex vivo and in vivo; their locations matched those observed in the histological sections, µCT images, and cleared specimens of barium‐perfused tissues. The ability to visualize cartilage canal blood vessels by MRI, without using a contrast agent, will allow future longitudinal studies to evaluate their role in developmental orthopedic disease. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:2006–2012, 2013     

In vivo deformation of thin cartilage layers: Feasibility and applicability of T2* mapping

The objectives of this study were as follows: (i) to assess segmentation consistency and scan precision of T2* mapping of human tibio‐talar cartilage, and (ii) to monitor changes in T2* relaxation times of ankle cartilage immediately following a clinically relevant in vivo exercise and during recovery. Using multi‐echo gradient recalled echo sequences, averaged T2* values were calculated for tibio‐talar cartilage layers in 10 healthy volunteers. Segmentation consistency and scan precision were determined from two repeated segmentations and two repeated acquisitions with repositioning, respectively. Subsequently, acute in vivo cartilage loading responses were monitored by calculating averaged tibio‐talar T2* values at rest, immediately after (i.e., deformation) and at 15 min (i.e., recovery) following a 30‐repetition knee bending exercise. Precision errors attained 4–6% with excellent segmentation consistency point estimates (i.e., intra‐rater ICC of 0.95) and acceptable limits of confidence. At deformation, T2* values were increased in both layers [+16.1 (10.7)%, p = 0.004 and +17.3 (15.3)%, p = 0.023, for the talus and tibia, respectively] whereas during recovery no significant changes could be established when comparing to baseline [talar cartilage: +5.2 (8.2)%, p = 0.26 and tibial cartilage: +6.6 (10.4)%, p = 0.23]. T2* mapping is a viable method to monitor deformational behavior in thin cartilage layers such as ankle cartilage. Longitudinal changes in T2* can be reliably appraised and require at least 4–6% differences to ascertain statistical significance. The ability to detect considerable change even after non‐strenuous loading events, endorses T2* mapping as an innovative method to evaluate the effects of therapeutic exercise on thin cartilage layers. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:771–778, 2016.     

T2* mapping in an equine articular groove model: Visualizing changes in collagen orientation

T2* mapping is promising for the evaluation of articular cartilage collagen. In this work, a groove model in a large animal is used as a model for posttraumatic arthritis. We hypothesized that T2* mapping could be employed to differentiate between healthy and (subtly) damaged cartilage. Eight carpal joints were obtained from four adult Shetland ponies that had been included in the groove study. In this model, grooves were surgically created on the proximal articular surface of the intermediate carpal bone (radiocarpal joint) and the radial facet of the third carpal bone (middle carpal joint) by either coarse disruption or sharp incision. After 9 months, T2* mapping of the entire carpal joint was carried out on a 7.0-T whole-body magnetic resonance imaging (MRI) scanner by means of a gradient echo multi-echo sequence. Afterwards, assessment of collagen orientation was carried out based on Picrosirius Red-stained histological sections, visualized by polarized light microscopy (PLM). The average T2* relaxation time in grooved samples was lower than in contralateral control sites. Opposite to the grooved areas, the “kissing sites” had a higher average T2* relaxation time than the grooved sites. PLM showed mild changes in orientation of the collagen fibers, particularly around blunt grooves. This work shows that T2* relaxation times are different in healthy cartilage vs (early) damaged cartilage, as induced by the equine groove model. Additionally, the average T2* relaxation times are different in kissing lesions vs the grooved sites.     

High resolution T21 mapping in assessment of knee articular cartilage on 3T MRI

ObjectiveTo evaluate the spectrum of T21 values in healthy cartilage of young asymptomatic adults on high resolution 3T MRI.MethodsA total of 50 asymptomatic adult volunteers with age ranging from 18 to 35 years were enrolled for the study with the purpose of assessing T21 values in healthy cartilage without any degenerative changes. The articular cartilage was assessed on two sections, one each through the medial and lateral compartments. The cartilage was segmented into 8 regions through the tibio-femoral and patella-femoral joints. Further post processing was done using multiple ROI placement to delineate ROI areas for calculation of full thickness and zonal (superficial and deep) T21 values. Thus, a total of 1200 ROI areas (50 volunteers, 8 segments, and 3 areas for each segment) were assessed.ResultsThe results revealed a superior bulk T21 value of 29.2 ± 3.6 ms from the posterior medial femoral cartilage and 26.1 ± 3.1 ms from the patellar region. Intermediate values were obtained from posterior lateral femoral cartilage, central femoral cartilage, and trochlea. The tibial plateau cartilage had the lowest values – 19.6 ± 2.6 ms for the medial tibial plateau and 20.6 ± 2.8 ms for lateral tibial plateau. The study demonstrated substantial regional physiological variation existing in the T21 values across various regions of the knee joint, which could be attributed to varying amounts of shearing forces across the joint. No significant differences were noted in bulk T21 values between the two genders, with only the trochlear segment revealing significantly increased values in males (p = 0.007). All the cartilage segments revealed significantly increased T21 values in the superficial zone as compared to the deep zone.ConclusionThere is a significant regional difference in the bulk T21 values of articular cartilage in a normal physiological state across various joint segments. A zonal gradient with increasing values from the deep to the superficial zone also exists. These findings can prove invaluable in assessing changes in T21 values occurring in diseased/degenerative cartilage.     

Characterization of cellular and matrix alterations in the early pathogenesis of osteochondritis dissecans in pigs using second harmonic generation and two‐photon excitation fluorescence microscopy

Osteochondritis dissecans is a joint disease that is observed in several species. The disease can develop as a cause of ischemic chondronecrosis in the epiphyseal growth cartilage. Some lesions of chondronecrosis undergo spontaneous resolution, but it is not possible to predict whether a lesion will resolve or progress and require intervention. Proliferation of cells into clusters occurs at the lesion margin, but it is unclear if the clusters have a repair function. The aims of the current study were to examine clusters and potential matrix changes in response to ischemic chondronecrosis in the distal femur of 10 pigs aged 70–180 days using advanced microscopy based on two‐photon excitation fluorescence and second harmonic generation. These microscopy techniques can perform 3D imaging of cells and collagen without staining. The results indicated a lower collagen density in the chondronecrotic areas compared to the normal growth cartilage, and fissures and breaks in the matrix integrity were demonstrated that potentially can propagate and cause osteochondritis dissecans. A higher number of cells in clusters was correlated with reduction in collagen density in the lesions. Some of the cells in the clusters had a morphology similar to progenitor cells, suggesting a potential repair role of the clusters. The study has shed further light on the secondary responses after initial lesion formation, which information can be of potential use to create models that can predict lesion progression and that may hence avoid unnecessary interventions in the future. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2089–2098, 2018.

     

Characterization of prostate cancer using T2 mapping at 3 T: A multi-scanner study

Rationale and objectivesTo assess the prostate T2 value as a predictor of malignancy on two different 3 T scanners.Patients and methodsEighty-three pre-prostatectomy multiparametric MRIs were retrospectively evaluated [67 obtained on a General Electric MRI (scanner 1) and 16 on a Philips MRI (scanner 2)]. After correlation with prostatectomy specimens, readers measured the T2 value of regions-of-interest categorized as “cancers”, “false positive lesions”, or “normal tissue”.ResultsOn scanner 1, in PZ, cancers had significantly lower T2 values than false positive lesions (P = 0.02) and normal tissue (P = 2 × 10⁻⁹). Gleason ≥ 6 cancers had similar T2 values than false positive lesions and significantly higher T2 values than Gleason ≥ 7 cancers (P = 0.009). T2 values corresponding to a 25% and 75% risk of Gleason ≥ 7 malignancy were respectively 132 ms (95% CI: 129–135 ms) and 77 ms (95% CI: 74–81 ms). In TZ, cancers had significantly lower T2 values than normal tissue (P = 0.008), but not than false positive findings. Mean T2 values measured on scanner 2 were not significantly different than those measured on scanner 1 for all tissue classes.ConclusionAll tested tissue classes had similar mean T2 values on both scanners. In PZ, the T2 value was a significant predictor of Gleason ≥ 7 cancers.     

3D‐isotropic high‐resolution morphological imaging and quantitative T2 mapping as biomarkers for gender related differences after matrix‐associated autologous chondrocyte transplantation (MACT)

The aim of this study was to determine in vivo high‐resolution morphological and biochemical gender related differences in cartilage repair tissue (MACT). Forty patients were examined clinically and by MR scans at 3T‐MRI (coronal 3D True‐FISP sequence for morphologic assessment and multi‐echo spin‐echo T2‐mapping for biochemical assessment of healthy cartilage and MACT cartilage). Mean T2 values in repair tissue in the deep zone showed significantly shorter T2 times in females (p = 0.009, female 43.5 ± 9.8 vs. male 48.2 ± 7.7 ms). The superficial zone showed higher T2 values than the deep zone in both the groups (female 48.5 ± 9.8, males 52.6 ± 11.0 ms) without significant difference between female and male patients. Native control cartilage showed no statistically significant differences for T2 between females and males. The subdivisions “structure of the repair tissue” and “subchondral bone” of the MOCART score showed statistically significant differences between females and males (p = 0.026 and p = 0.007) as well as the Lysholm score (p = 0.03). Our investigations revealed differences between female and male patients after MACT of the knee in clinical outcome and advanced morphological and biochemical MRI. The presented imaging biomarkers can depict subtle changes after cartilage regeneration procedures and might help to understand gender related differences after cartilage repair procedures. © 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 32:1341–1348, 2014.     

Possibility of quantitative T2‐mapping MRI of cartilage near metal in high tibial osteotomy: A human cadaver study

T2‐mapping is a widely used quantitative MRI technique in osteoarthritis research. An important challenge for its application in the context of high tibial osteotomy (HTO) is the presence of metallic fixation devices. In this study, we evaluated the possibility of performing T2‐mapping after a HTO, by assessing the extent of magnetic susceptibility artifacts and the influence on T2 relaxation times caused by two commonly used fixation devices. T2‐mapping with a 3D fast spin‐echo sequence at three Tesla was performed on 11 human cadaveric knee joints before and after implantation of a titanium plate and screws (n = 5) or cobalt chrome staples (n = 6). Mean T2 relaxation times were calculated in six cartilage regions, located in the distal and posterior cartilage of femoral condyles and the cartilage of tibial plateaus, both medially and laterally. T2 relaxation times before and after the implantation were compared with paired t‐tests and Wilcoxon rank tests. Due to the extent of the magnetic susceptibility artifact, it was not possible to segment the knee cartilage and thus calculate T2 relaxation times in the lateral weight‐bearing femoral and tibial cartilage regions only in the cobalt chrome group. In all cartilage regions of the titanium implanted knees and those unaffected by artifacts due to cobalt chrome implants, T2 relaxation times did not significantly differ between the two scans. Our results suggest that accurate T2‐mapping after a HTO procedure is possible in all areas after implantation of a titanium fixation device and in most areas after implantation of a cobalt chrome fixation device. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1206–1212, 2018.

     

T2 relaxation time and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) of human patellar cartilage at 1.5 T and 9.4 T: Relationships with tissue mechanical properties.

Quantitative magnetic resonance imaging (MRI) techniques have been developed for noninvasive assessment of the structure of articular cartilage. T2 relaxation time is sensitive to the integrity and orientation of the collagen network, while T1 relaxation time in presence of Gd-DTPA2- (dGEMRIC) reflects the proteoglycan content of cartilage. In the present study, human patellar cartilage samples were investigated in vitro to determine the ability of MRI parameters to reveal topographical variations and to predict mechanical properties of cartilage at two different field strengths. T2 and dGEMRIC measurements at 1.5 T and 9.4 T were correlated with the static and dynamic compressive moduli at six anatomical locations of the patellar surface. Statistically significant linear correlations were observed between MRI and mechanical parameters at both field strengths, especially between T2 and Young's modulus. No significant difference was found between the T2 measurements at different field strengths in predicting mechanical properties of the tissue. Topographical variation of T2 values at both field strengths was similar to that of Young's moduli. The current results demonstrate the feasibility of quantitative MRI, particularly T2 mapping, to reflect the mechanical properties of human patellar cartilage at both field strengths.     

T2* mapping of subtalar cartilage: Precision and association between anatomical variants and cartilage composition

Hindfoot arthritis is an important contributor to foot pain and physical disability. While the subtalar joint (STJ) is most frequently affected, anatomical variants such as facet configuration were suggested to further STJ cartilage deterioration. T2* mapping enables detection of ultra‐structural cartilage change, particularly in thin cartilage layers, but its feasibility in the STJ has not yet been evaluated. The purpose of this study was to evaluate segmentation consistency and inter‐scan short‐term precision error of T2* mapping of talocalcaneal cartilage and to investigate the relationship between facet configuration and STJ T2* values. Using 3Tesla morphological magnetic resonance imaging, STJ configuration was categorized according to the degree of fusion between anterior, medial, or posterior facets. Subsequently, two repeats of multi‐echo gradient recalled echo sequences were performed to obtain T2* maps with repositioning. Segmentation consistency of T2* values attained an ICC of 0.90 (95%CI 0.69–0.99). Precision errors comprised a coefficient of variation (CV) ranging 0.01–0.05, corresponding to a root mean square CV of 0.03–0.04. A 2‐joint configuration type (i.e., fused anterior‐medial facets) was significantly associated with a decrease in posterior facet T2* values (β = ?0.6, p = 0.046). STJ T2* mapping is a reliable method requiring at least a 4% difference within people to enable detection of significant change. Anatomical variants in STJ configuration were associated with T2* values with the more stable 3‐joint types exhibiting more favorable cartilage outcomes. Longer‐term larger‐scaled studies focusing on arthritis pathology are needed to further support the use of T2* mapping in hindfoot disease monitoring. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1969–1976, 2016.

     

T2 mapping in the knee after microfracture at 3.0 T: correlation of global T2 values and clinical outcome - preliminary results

OBJECTIVE: The aim of our study was to correlate global T2 values of microfracture repair tissue (RT) with clinical outcome in the knee joint. METHODS: We assessed 24 patients treated with microfracture in the knee joint. Magnetic resonance (MR) examinations were performed on a 3T MR unit, T2 relaxation times were obtained with a multi-echo spin-echo technique. T2 maps were obtained using a pixel wise, mono-exponential non-negative least squares fit analysis. Slices covering the cartilage RT were selected and region of interest analysis was done. An individual T2 index was calculated with global mean T2 of the RT and global mean T2 of normal, hyaline cartilage. The Lysholm score and the International Knee Documentation Committee (IKDC) knee evaluation forms were used for the assessment of clinical outcome. Bivariate correlation analysis and a paired, two tailed t test were used for statistics. RESULTS: Global T2 values of the RT [mean 49.8ms, standards deviation (SD) 7.5] differed significantly (P<0.001) from global T2 values of normal, hyaline cartilage (mean 58.5ms, SD 7.0). The T2 index ranged from 61.3 to 101.5. We found the T2 index to correlate with outcome of the Lysholm score (r(s)=0.641, P<0.001) and the IKDC subjective knee evaluation form (r(s)=0.549, P=0.005), whereas there was no correlation with the IKDC knee form (r(s)=-0.284, P=0.179). CONCLUSION: These findings indicate that T2 mapping is sensitive to assess RT function and provides additional information to morphologic MRI in the monitoring of microfracture.     

In vivo T(1rho) and T(2) mapping of articular cartilage in osteoarthritis of the knee using 3 T MRI

OBJECTIVE: Evaluation and treatment of patients with early stages of osteoarthritis (OA) is dependent upon an accurate assessment of the cartilage lesions. However, standard cartilage dedicated magnetic resonance (MR) techniques are inconclusive in quantifying early degenerative changes. The objective of this study was to determine the ability of MR T1rho (T(1rho)) and T(2) mapping to detect cartilage matrix degeneration between normal and early OA patients. METHOD: Sixteen healthy volunteers (mean age 41.3) without clinical or radiological evidence of OA and 10 patients (mean age 55.9) with OA were scanned using a 3Tesla (3T) MR scanner. Cartilage volume and thickness, and T(1rho) and T(2) values were compared between normal and OA patients. The relationship between T(1rho) and T(2) values, and Kellgren-Lawrence scores based on plain radiographs and the cartilage lesion grading based on MR images were studied. RESULTS: The average T(1rho) and T(2) values were significantly increased in OA patients compared with controls (52.04+/-2.97ms vs 45.53+/-3.28ms with P=0.0002 for T(1rho), and 39.63+/-2.69ms vs 34.74+/-2.48ms with P=0.001 for T(2)). Increased T(1rho) and T(2) values were correlated with increased severity in radiographic and MR grading of OA. T(1rho) has a larger range and higher effect size than T(2), 3.7 vs 3.0. CONCLUSION: Our results suggest that both in vivo T(1rho) and T(2) relaxation times increase with the degree of cartilage degeneration. T(1rho) relaxation time may be a more sensitive indicator for early cartilage degeneration than T(2). The ability to detect early cartilage degeneration prior to morphologic changes may allow us to critically monitor the course of OA and injury progression, and to evaluate the success of treatment to patients with early stages of OA.     

T2* mapping of ovine intervertebral discs: Normative data for cervical and lumbar spine

To obtain T2* values in histologically evaluated healthy ovine intervertebral discs of the cervical and lumbar spine. Intervertebral discs of nine sheep and nine lambs underwent histological assessment with the modified Boos score for grading of disc degeneration. Discs with a score <10 points (maximum = 40 points) underwent T2* mapping (n = 64). Mid‐sagittal T2* values were obtained in five regions: Anterior annulus fibrosus, anterior nucleus pulposus, central nucleus pulposus, posterior nucleus pulposus, and posterior annulus fibrosus. We noted a zonal T2* distribution with high values in the central nucleus and low T2* values in the anterior and posterior annulus fibrosus. The T2* values were higher in lamb than in sheep IVDs for both cervical and lumbar spine (p < 0.001). The T2* values were also higher in the cervical than in the lumbar spine (p = 0.029 for sheep and p < 0.001 for lamb IVDs). The T2* values obtained in these ovine intervertebral discs can serve as baseline values for future T2* measurements both in health and disease. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:717–724, 2016.     

Magnetic resonance measurements of tissue quantity and quality using T2* relaxometry predict temporal changes in the biomechanical properties of the healing ACL

The purpose of this study was to develop a magnetic resonance T₂* relaxometry‐based multiple linear regression model to predict the structural properties of the healing anterior cruciate ligament (ACL) over a 24‐week healing period following ACL repair in Yucatan minipigs. Two hypotheses were tested: (i) that a regression model based on ACL sub‐volumes containing short and long T₂* relaxation times would outperform a competing model based on sub‐volumes of short T₂* relaxation times only; and (ii) that an optimized regression model would be capable of predicting ACL structural properties between 6 and 24 weeks post‐repair. ACLs were imaged in 24 minipigs (8/group) at either 6, 12, or 24 weeks after ACL repair. The structural properties of the ACLs were determined from tensile failure tests. Four multiple linear regression models of increasing complexity were fitted to the data. Akaike Information Criterion values and Bland–Altman tests were used to compare model performance and to test the hypotheses. The structural properties predicted from the multiple linear regression model that was based on the change in ACL sub‐volumes of both the short and long T₂* relaxation times over the healing period were in closest agreement to the measured values, suggesting that the amounts of both organized and disorganized collagen, and the change in these quantities over time, are required to predict the structural properties of healing ACLs accurately. Clinical significance: our time‐specific, T₂*‐based regression model may allow us to estimate the structural properties of ACL repairs in vivo longitudinally. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1701–1709, 2018.     

腰椎间盘MRI或T2相变化与冯氏临床分型（四步腰型）关系的研究

目的探讨腰椎间盘突出症患者MRI T2相信号、性别、年龄、病程、临床分型之间的关系,验证冯氏临床分型与腰椎间盘MRI T2相信号变化的相关性。方法本研究收集102例腰椎间盘突出症患者的临床资料,根据腰椎间盘MRI T2相信号分3型,根据临床分型分为A、B两组,对患者性别、年龄、病程、腰型、腰椎间盘T2相信号变化,用医学统计软件spss13.0进行秩和检验和非参数相关性检验。结果1、MRI T2相信号与性别、年龄不相关;2、MRI T2相信号变化与临床分型密切相关,结论椎间盘T2相信号变化与临床分型有很强的相关性,但要结合临床综合判断,我们要重新认识椎间盘T2相信号变化的临床意义。     

Verification of measurements of lumbar spinal dimensions in T1- and T2-weighted magnetic resonance imaging sequences

Background contextMagnetic resonance imaging (MRI) is commonly used to assess patients with lumbar spinal stenosis. No single MRI sequence has been shown to be superior in spinal canal measurements. There are also cost concerns for the increased clinical and research use of MRI. Using only a single sequence may lower the financial burden; however, this requires spinal canal measurements in both T1 and T2 MRI to be reliable. Evidence for this is currently lacking.PurposeThe aim of this study was to determine the intra- and inter-reader reliability of MRI measurements of the lumbar spine and the reliability of measurements using T1- and T2-weighted MRI films.Study design/settingRetrospective study.Patient sampleForty-two randomly selected patients who underwent spinal stenosis surgery.Outcome measuresLumbar spinal canal measurements and reliability analysis between T1- and T2-weighted MRI.MethodsQualitative ratings of MRI features were performed according to previously published criteria by 2 independent readers (JP-YC, HS). Measurements in axial scan included midline anteroposterior (AP) vertebral body diameter, midvertebral body width, midline AP spinal canal diameter, midline AP dural sac diameter, spinal canal width/interpedicular distance, pedicle width (right and left), and lamina angle. Measurements in the sagittal scan included midline AP body diameter, midvertebral body height, and AP spinal canal diameter. Cronbach alpha was used to characterize intra- and inter-reader reliability for qualitative rating data. Similarly, T1 and T2 comparison also was performed in the same manner.ResultsGood to excellent intra- and interobserver reliability was obtained for all measurements. Reliability analysis of all T1 and T2 measurements was excellent.ConclusionsEither T1 or T2 images can be used for measurements of spinal canal dimensions. These findings are of importance, as not every patient undergoing preoperative MRI assessment will necessarily have both sequences performed and only a single sequence is required for research studies. Our findings are also of relevance in measurement of lumbar canal diameters.