Sagittal Magnetic Resonance Imaging Scans Research Articles

Does Tibial Plateau Slope and Depth Influence ACL Strain In Vivo?

The anterior cruciate ligament (ACL) is loaded under tension when the tibia translates anteriorly relative to the femur. The shape of the articular surfaces of the tibiofemoral joint may influence the amount of anterior tibial translation under compressive loading. Thus, a steep lateral tibial plateau and a shallow medial plateau are thought to be risk factors for ACL injury. The purpose of this study was to evaluate whether tibial plateau slope and depth influence peak ACL strain during a single-leg jump. We hypothesized that there would be a significant correlation between tibial plateau slope and depth with ACL strain. Descriptive laboratory study. A total of 17 healthy participants (8 male, 9 female) were assessed using magnetic resonance imaging (MRI) and high-speed biplanar radiography to obtain peak ACL strain during a single-leg jump. Two orthopaedic surgeons used the sagittal plane MRI scans to measure the medial and lateral tibial plateau slopes and the medial tibial plateau depth. The intraclass correlation coefficient was used to assess measurement reliability, and the Spearman rank correlation was used to evaluate the relationship between measurements of tibial morphology and peak ACL strain during the single-leg jump. The overall range of intraclass correlation coefficients for intra- and interrater reliability of the medial and lateral tibial plateau slopes and medial plateau depth was 0.59 to 0.97. No significant correlations were found between peak ACL strain and any of the slope or depth measurements. In this cohort of healthy participants, correlations between any of the tibial plateau measurements with peak ACL strain during a single-leg jump were not detected. These findings are consistent with prior work, suggesting that tibial plateau slope and depth may not be linked to risk for ACL rupture. However, it is possible that tibial plateau morphology may interact with other factors to increase ACL injury risk or that individuals with extreme slope angles may produce differing results. This study enhances the knowledge of the loading mechanisms for the ACL and thus improves the understanding of risk factors for ACL injury.

Effects of tendon elongation on plantar pressure and clinical outcomes: A comparative analysis between open repair and minimally invasive surgery.

The aim of this study was to assess whether variances in Achilles tendon elongation are linked to dissimilarities in the plantar pressure distribution following two different surgical approaches for an Achilles tendon rupture (ATR). All patients who were treated with open or minimally invasive surgical repair (MIS) and were over 2 years post their ATR were eligible for inclusion. A total of 65 patients with an average age of 43 ± 11 years were included in the study. Thirty-five patients were treated with open repair, and 30 patients were treated with MIS. Clinical outcomes were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) and ATR Score (ATRS). Achilles tendon elongation was measured using axial and sagittal magnetic resonance imaging scans. Plantar pressure measurements for the forefoot, midfootand hindfoot during gait were divided into percentages based on total pressure, measured in g/cm2 for each area. The average AOFAS score was found 'excellent' (93 ± 2.8) in the MIS group, while it was found 'good' (87.4 ± 5.6) in the open repair group. In addition, the MIS group showed significantly superior ATRS scores (78.8 ± 7.4) compared to the open repair group (56.4 ± 15.4) (p < 0.001). The average tendon elongation in the MIS group was 11.3 ± 2 mm, while it was 17.3 ± 4.3 mm(p < 0.001) in the open repair group. While the open repair group showed significantly higher plantar pressure distribution in the initial contact and preswing phases compared to uninjured extremities, there was no significant difference between the uninjured extremities and the MIS group. In conclusion, the findings of this study demonstrated that minimally invasive surgery was associated with less tendon elongation, more proximity to the plantar pressure distributions of the uninjured extremity and superior clinical outcomes compared to open surgical repair. Therefore, minimally invasive surgery may be considered a more suitable option for acute Achilles tendon repair to achieve overall better outcomes. Level III.

Association of Lateral Extra-Articular Tenodesis With Improved Graft Maturity on MRI 2 Years After ACL Reconstruction With Quadriceps Tendon Autograft in Skeletally Immature Athletes.

Quadriceps tendon autograft (QTA) has recently gained popularity in the treatment of anterior cruciate ligament (ACL) ruptures in pediatric patients. The addition of lateral extra-articular tenodesis (LET) to an ACL reconstruction (ACLR) has been found to reduce the risk of ACL retear in high-risk patients. To (1) compare ACL graft maturity using signal intensity ratios (SIRs) on magnetic resonance imaging (MRI) scans in skeletally immature patients undergoing ACLR with QTA either with or without concomitant LET and (2) evaluate LET safety by calculating the physeal disturbance-related reoperation rate in the ACLR+LET group. Cohort study; Level of evidence, 3. The records of patients aged ≤18 years who underwent ACLR between 2015 and 2021 were reviewed retrospectively. Patients undergoing ACLR with QTA who had open distal femoral and proximal tibial physes on MRI scans and a minimum 2-year follow-up data were included. SIR values were measured on sagittal MRI scans by averaging the signal at 3 regions of interest along the ACL graft and dividing by the signal of the posterior cruciate ligament at its insertion. Statistical analysis was performed to evaluate differences in SIR values at 6 months, 1 year, and 2 years postoperatively in patients who underwent ACLR alone versus ACLR+LET. Overall, 29 patients were included in the study: 16 patients in the ACLR+LET group and 13 patients in the ACLR-only group. There were no significant differences in SIR values between groups at the 6-month or 1-year postoperative timepoints. At 2 years postoperatively, the median SIR of the ACLR+LET group was significantly lower than that of the ACLR-only group on both univariate (1.33 vs 1.86, respectively, P = .0012) and multivariate regression analyses adjusting for both sex and surgical technique (β = -0.49 [95% CI, -0.91 to -0.05]; P = .029). There were no cases of reoperation for physeal disturbance in patients who underwent ACLR+LET. The addition of LET to an ACLR with QTA was associated with lower average SIR values and thus improved graft maturity at 2 years postoperatively compared with ACLR alone in skeletally immature patients. The addition of LET to an ACLR was found to be safe in skeletally immature patients.

Association of Trochlear Length on Sagittal MRI to Trochlear Dysplasia in Knees With Patellar Instability.

Trochlear dysplasia is a primary risk factor for patellar instability and leads to loss of the osteochondral constraint of the patella. Trochleoplasty techniques include the Peterson grooveplasty, which alters the length of the trochlea; however, a radiographic measurement of trochlear length to support this has not been described. To describe measurements to quantify trochlear length on sagittal magnetic resonance imaging in patients with and without patellar instability and to correlate trochlear length with measurements of trochlear dysplasia. Cross-sectional study; Level of evidence, 3. A total of 66 age- and sex-matched knees (36 female and 30 male; mean age, 20.8 ± 4.8 years) were included in this study, of which 33 had patellar instability. Trochlear extension length (TEL) and trochlear alpha angle (TAA) were measured on 3 sagittal magnetic resonance imaging scans (center of the knee, center of the medial condyle, and center of the lateral condyle), and measurements were compared between symptomatic and control knees. Receiver operating characteristic curve analysis was performed, and the area under the curve (AUC) was calculated to describe the accuracy of each measurement to distinguish between knees with and without patellar instability. Linear and multivariate regression analyses were performed to assess the relationship between sagittal measurements and axial measurements of trochlear dysplasia, including lateral trochlear inclination, sulcus angle, and trochlear depth, as well as patient size reflected by the epicondylar distance. In symptomatic knees, the central trochlea extended more proximally than in control knees, as determined by the TEL (14.0 ± 3.0 vs 11.5 ± 2.3 mm, respectively; P < .001) and TAA (68.4° ± 3.8° vs 70.5° ± 3.4°, respectively; P = .017). AUC calculations showed that a TEL ≥11 mm at the central trochlea was predictive of patellar instability in both male and female knees (AUC = 0.83 and 0.77, respectively), as was a TAA ≤67° in female knees (AUC = 0.72). An independent association between the central TEL and sulcus angle was found. The central TEL showed a weak correlation with patient size, as measured by the epicondylar distance, while the TAA did not. In knees with symptomatic patellar instability, the central trochlea was found to extend 2.5 mm more proximally than in control knees, and this increase in length correlated with severity of trochlear dysplasia. As radiographic examinations of the trochlea and grooveplasty procedures are often based on the proximal extent of the cartilaginous trochlea, further studies are needed to identify the role of trochlear length in the assessment and treatment of trochlear dysplasia in the setting of patellar instability.

MRI Does Not Improve Inter- or Intrarater Reliability for Hip Arthritis Grading Systems

Background: Magnetic resonance imaging (MRI) scans and radiographs are often utilized in assessing for preoperative osteoarthritis in patients undergoing hip preservation surgery. Purpose: To determine if MRI scans improve inter- or intrarater reliabilities over radiographs for findings of hip arthritis. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: Anteroposterior and cross-table lateral radiographs as well as a representative coronal and sagittal T2-weighted MRI scan were reviewed for 50 patients by 7 experienced subspecialty hip preservation surgeons, with a minimum experience of 10 years. Radiographs and MRI scans were assessed for joint space narrowing, subchondral cysts, osteophytes, subchondral sclerosis, Likert osteoarthritis grade (none, mild, moderate, or severe), and Tönnis grade. MRI scans were also evaluated for bony edema, heterogeneous articular cartilage, and chondral defects. Inter- and intrarater reliabilities were calculated utilizing the Fleiss method with a 95% CI. Results: The scans of 50 patients (28 female and 22 male) with a mean age of 42.8 years (SD, 14.2 years; range, 19-70 years) were reviewed. Radiographs revealed fair agreement for joint space narrowing (κ = 0.25 [95% CI, 0.21-0.30]), osteophytes (κ = 0.26 [95% CI, 0.14-0.40]), Likert osteoarthritis grading (κ = 0.33 [95% CI, 0.28-0.37]) and Tönnis grade (κ = 0.30 [95% CI, 0.26-0.34). Radiographs revealed moderate agreement for subchondral cysts (κ = 0.53 [95% CI, 0.35-0.69]). MRI scans demonstrated poor to fair agreement for joint space narrowing (κ = 0.15 [95% CI, 0.09-0.21]), subchondral sclerosis (κ = 0.27 [0.19-0.34]), heterogeneous articular cartilage (κ = 0.07 [95% CI, 0.00-0.14]), Likert osteoarthritis grade (κ = 0.19 [95% CI, 0.15-0.24]), and Tönnis grade (κ = 0.20 [95% CI, 0.15-0.24]). MRI scans demonstrated substantial agreement for subchondral cysts (κ = 0.73 [95% CI, 0.63-0.83]). Intrarater reliabilities were statistically improved compared with interrater reliabilities, but no differences were found between radiographs and MRI scans for joint space narrowing, subchondral cysts, osteophytes, osteoarthritis grade, or Tönnis grade. Conclusion: Radiographs and MRI scans had substantial limitations and inconsistency between raters in evaluating common markers of hip osteoarthritis. MRI scans demonstrated strong reliability in evaluating for subchondral cysts but did not improve the interobserver variability of grading hip arthritis.

Spontaneous Thoracic Spinal Epidural Hematoma During Pregnancy

Spontaneous Thoracic Spinal Epidural Hematoma During Pregnancy

Bone quality in patients with osteoporosis undergoing lumbar fusion surgery: analysis of the MRI-based vertebral bone quality score and the bone microstructure derived from microcomputed tomography

Osteoporosis is a risk factor for instrumentation failure in spine surgery. Bone strength is commonly assessed by bone mineral density (BMD) as a surrogate marker. However, BMD represents only a portion of bone strength and does not capture the qualitative dimensions of bone. Recently, the magnetic resonance imaging (MRI)-based vertebral bone quality (VBQ) score was introduced as a novel marker of bone quality. However, it is still unclear if the VBQ score correlates with in-vivo bone microstructure. The aims of the study were (1) to demonstrate differences in MRI-based (VBQ) and in-vivo (microcomputed tomography; μCT) bone quality between osteopenic/osteoporotic and normal bone, (2) to show the correlation between VBQ, bone microstructure and volumetric BMD (vBMD), and (3) to determine the predictive value of the VBQ score for the prevalence of osteopenia/osteoporosis. Retrospective cross-sectional study. 267 patients who underwent posterior lumbar fusion surgery from 2014 to 2021 at a single academic institution. Bone biopsies were harvested intraoperatively in 118 patients. VBMD, VBQ score, and bone microstructure parameters derived from μCT. Quantitative computed tomography (QCT) measurements were performed at the lumbar spine and the L1/L2 average was used to categorize patients with a vBMD ≤120mg/cm3 as osteopenic/osteoporotic. The VBQ score was determined by dividing the median signal intensity of the L1-L4 vertebrae by the signal intensity of the cerebrospinal fluid using sagittal T1-weighted MRI scans. Intraoperative bone biopsies from the posterior superior iliac spine were obtained and evaluated with μCT. VBQ scores and μCT parameters were compared between the normal and the osteopenic/osteoporotic group. Correlations between VBQ score, μCT parameters and vBMD were assessed with Spearman's correlation (ρ). Receiver operating characteristic (ROC) analysis was performed to determine the VBQ score as a predictor for osteopenia/osteoporosis. Multiple linear regression analysis with vBMD L1/L2 as outcome was used to identify independent predictors from VBQ, μCT parameters and demographics. 267 patients (55.8% female, age 63.3 years, BMI 29.7 kg/m2; n=118 with bone biopsy) with a prevalence of osteopenia/osteoporosis of 65.2% were analyzed. In the osteopenic/osteoporotic group the VBQ score, structured model index (SMI), and trabecular separation (Tb.Sp) were significantly higher, whereas bone volume fraction (BV/TV), connectivity density (Conn.D) and trabecular number (Tb.N) were significantly lower. There were significant correlations between VBQ and μCT parameters ranging from ρ=-.387 to ρ=0.314 as well as between vBMD and μCT parameters ranging from ρ=-.425 to ρ=.421, and vBMD and VBQ (ρ=-.300, p<.001). ROC analysis discriminated osteopenia/osteoporosis with a sensitivity of 84.7% and a specificity of 40.6% at a VBQ score threshold value of 2.18. Age, BV/TV and trabecular thickness (Tb.Th), but not VBQ, were significant independent predictors for vBMD (corrected R2=0.434). This study demonstrated for the first time that the VBQ score is associated with trabecular microstructure determined by μCT. The bone microstructure and VBQ score were significantly different in patients with impaired vBMD. However, the ability to predict osteopenia/osteoporosis with the VBQ score was moderate. The VBQ score appears to reflect additional bone quality characteristics and might have a complementary role to vBMD. This enhances our understanding of the biological background of the radiographic VBQ score and might be a take-off point to evaluate the clinical utility of it as non-invasive screening tool for bone quality.

P129 Quantification of longitudinal joint and cartilaginous changes within ankles with haemophilia joint degeneration using MRI imaging

Abstract Background/Aims Haemophilia is an X-linked recessive genetic disorder characterised by episodes of spontaneous and traumatic intra-articular bleeding. 90% of bleeds are of musculoskeletal origin, with the ankle being most affected joint. Recurrent bleeding results in haemosiderin accumulation, linked to progressive, end-stage ankle haemarthropathy in adolescent and adult patients. Magnetic Resonance Imaging (MRI) is gold-standard for the evaluation of early soft tissue and cartilage changes in ankles with haemarthropathy. This study utilised MRI sequences to quantify longitudinal changes within the ankle joint, via changes in cartilage thickness (CT), subchondral thickness (ST) and joint space width (JS) over time. Methods Clinical T1 Sagittal MRI scans of HJD ankles were selected (N = 5). Each patient had a minimum of two MRI scans available, at least one year apart, to allow for comparison of longitudinal changes. All images were identity coded but fully anonymised. The earliest available and most recent MRI scan were measured in three slices (medial, lateral and middle slice) and at different points along the joint space (anterior, middle and posterior). Measurements taken were cartilage thickness on the talar dome (CT) and the distance between the subchondral bone of the tibial plafond and talar dome (ST). The joint space width (JS) was then determined by subtracting CT from ST. Results Chondral thickness measurements showed most reduction, particularly at the antero-lateral aspect (-0.4mm) compared to the antero-medial and middle sections, with -0.24mm and -0.34mm (Table 1). ST and JS reduction was predominantly seen in the anterior joint, with most reduction in antero-lateral joint (-1.13mm). The posterior joint showed minimal reduction in the postero-medial and middle sections, with the posterior-lateral joint space width increasing (0.2mm). Subchondral thickness and joint space measurements were variable and did not demonstrate linear change over time. Conclusion A systematic longitudinal decrease in cartilage thickness was seen in the antero-lateral and antero-medial aspect of the ankle joint. The antero-lateral aspect of the ankle showed the greatest reduction in joint space and cartilage thickness. This suggests that this area of the joint is likely to provide the best early indications of haemarthropathy when using MRI as a diagnostic tool. Disclosure M. Schaper: None. M. Sharrock: None. R.A. Wilkins: None. A.C. Redmond: None.

Endoscopic Third Ventriculostomy: Our Experience of Consecutive 50 Cases at a Tertiary Care Center

Abstract Objective The aim of this study was to do a retrospective analysis of the various neurosurgical pathologies where endoscopic third ventriculostomy (ETV) was used and to evaluate the outcome and prognosis. Methods The retrospective data collection was done for the patients who underwent ETV with or without other adjunct procedures; the results were prepared for clinical presentation, diagnosis, surgical approach, and surgical goal; and success rate and prognosis were analyzed and compared with other studies. Results A total of 50 patients were included in the study, with overall success rate of ETV as 88%; aqueductal stenosis was the most common indication where ETV was used; headache and vomiting were the most common presenting complaints followed by ataxia and visual blurring; and ETV provided flexibility in its use with biopsy, abscess drainage, temporary external ventricular drain placement, etc. Conclusion ETV being superior to ventriculo-peritoneal shunt for obstructive hydrocephalus provides flexibility in its use and possibly is a useful adjunct to prevent postoperative hydrocephalus after endoscopic intraventricular surgery; proper case selection in accordance to ETV success score yields a better success rate. In experienced hands with proper precautions, perioperative complications can be kept at minimum. Wherever possible, in cases of obstructive hydrocephalus, especially in patients &gt;1 year of age, ETV should be the treatment of choice. We recommend a proper case selection, including preoperative detailed reading of sagittal magnetic resonance imaging scan, to improve the success rate with less complication.

Distance between the supraspinatus and long head of the biceps tendon on sagittal MRI: a new tool to identify anterior supraspinatus insertion injury

PurposeAnterior insertion of the supraspinatus muscle plays an essential role in rotator cuff tissue. We aimed to determine whether the distance between the midpoints of the supraspinatus central tendon and long head of the biceps tendon on a sagittal shoulder magnetic resonance imaging scan can help to preoperatively diagnose an injury of the anterior insertion of the supraspinatus.MethodThis retrospective study reviewed 103 patients with a full-thickness supraspinatus tendon tear: 50 patients with (injured group) and 53 patients without (intact group) anterior supraspinatus insertion tear. The inter-tendon distance was measured based on an oblique sagittal magnetic resonance imaging scan. SPSS was used for statistical analyses. Two independent samples t-test and receiver operating curve analysis were also performed.ResultsThe measurements of inter-tendon distance revealed good intra- and inter-observer reliabilities with intra-class correlation coefficients of 0.92 and 0.97, respectively. The inter-tendon distance of the injured group was significantly greater than that of the intact group (10.1 ± 2.7 vs 8.0 ± 2.3 mm, P < 0.001). The diagnostic ability of the inter-tendon distance was fair (area under the curve = 0.745), and a threshold of 9 mm had a specificity of 73% and sensitivity of 74%.ConclusionThe distance between the supraspinatus central tendon and long head of the biceps tendon on magnetic resonance imaging was greater in patients with anterior supraspinatus insertion injury than those without the injury. A distance of 9 mm may be the cut-off value and a good diagnosis marker for anterior supraspinatus insertion injury.Level of evidenceLevel III, diagnostic case–control study.

Accuracy of MRI and X-Ray Measurement of Displacement Distance of Humeral Lateral Condyle Fractures.

ObjectiveTo investigate the accuracy of X‐ray and magnetic resonance imaging (MRI) measurements in evaluating the displacement of humeral lateral condyle fracture (HLCF) in different positions of the forearm based on human cadaveric HLCF models.MethodsThree human cadaveric elbow HLCF fracture models were successfully established. The wrist joint was fixed, and the forearm was rotated forward along the mid‐axis. The maximum distance between the two segments of the lateral fracture gap was defined as LFS (lateral fracture space) distance, and the maximum distance between the two segments of the fracture gap at the anterior and posterior margins of the fracture model was defined as PFS (posterior fracture space). The LFS and PFS distances of the human cadaveric elbow HLCF fracture models were measured during forearm rotation at 0º, 45º, 90º, and 135º rotation using a Capture Motion System (CMS), positive and lateral elbow X‐ray, coronal and sagittal MRI scans, respectively, and the CMS measurements were considered as the true fracture gap distances. The values obtained by CMS, X‐ray, and MRI measurements for both LPS and PFS distances in the HLCF fracture model at each position during rotation were recorded. The LFS and PFS distances were measured by two independent orthopaedic and joint imaging physicians. The data were measured three times by each physician, and the final values were the average of the two measurements. The outcomes were determined by whether a statistical difference exists in the LFS and PFS among the CMS, X‐ray, and MRI groups.ResultsThe interobserver agreement tests between the two observers showed good agreement in the measurements. A multiple sample ANOVA showed statistical differences in the LFS distances of HLCF measured at 0º, 45º, 90º, and 135º rotated by three radiographic measurements (P < 0.05). The LFS distances obtained by MRI and CMS measurements were greater than those obtained by X‐ray measurement in all positions using the LSD test (P < 0.05), and no statistical difference was found between the CMS and MRI methods in each position (P > 0.05). The same results were observed in terms of PFS values obtained by CMS, X‐ray, and MRI measurements at 0º, 45º, 90º, and 135º pronation. It was statistically different among the three groups as shown by multiple sample ANOVA (P < 0.05). The CMS and MRI measurements were greater than the X‐ray measurements (P < 0.05), while no statistical difference was observed between the CMS and MRI measurements (P > 0.05).ConclusionX‐rays often underestimate the degree of displacement of HLCF fractures; MRI measurements are closer to the true values compared with X‐ray.

Serum Levels of Glial Fibrillary Acidic Protein and Neurofilament Light Protein Are Related to the Neurological Impairment and Spinal Edema after Traumatic Spinal Cord Injury.

Neurological examination in the acute phase after spinal cord injury (SCI) is often impossible and severely confounded by pharmacological sedation or concomitant injuries. Therefore, diagnostic biomarkers that objectively characterize severity or the presence of SCI are urgently needed to facilitate clinical decision-making. This study aimed to determine if serum markers of neural origin are related to: 1) presence and severity of SCI, and 2) magnetic resonance imaging (MRI) parameters in the very acute post-injury phase. We performed a secondary analysis of serological parameters, as well as MRI findings in patients with acute SCI (n = 38). Blood samples were collected between Days 1-4 post-injury. Serum protein levels of glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE), and neurofilament light protein (NfL) were determined. A group of 41 age- and sex-matched healthy individuals served as control group. In the group of individuals with SCI, pre-operative sagittal and axial T2-weighted and sagittal T1-weighted MRI scans were available for 21 patients. Serum markers of neural origin are different among individuals who sustained traumatic SCI depending on injury severity, and the extent of the lesion according to MRI in the acute injury phase. Unbiased Recursive Partitioning regression with Conditional Inference Trees (URP-CTREE) produced preliminary cut-off values for NfL (75.217 pg/mL) and GFAP (73.121 pg/mL), allowing a differentiation between individuals with SCI and healthy controls within the first 4 days after SCI. Serum proteins NfL and GFAP qualify as diagnostic biomarkers for the presence and severity of SCI in the acute post-injury phase, where the reliability of clinical exams is limited.

A Quantifiable Risk Factor for ACL Injury: Applied Mathematics to Model the Posterolateral Tibial Plateau Surface Geometry.

Background:The mechanism for traumatic ruptures of the native anterior cruciate ligament (ACL) is frequently a noncontact injury involving a valgus moment with internal rotation of the tibia. The abnormal rotation and translation of the lateral femoral condyle posteroinferiorly relative to the lateral tibial plateau is thought to be related to the geometry of the tibial plateau.Purpose/Hypothesis:The purpose of the study was to mathematically model the posterior tibial plateau geometry in patients with ACL injuries and compare it with that of matched controls. The hypothesis was that increased convexity and steepness of the posterior aspect of the lateral plateau would subject knees to higher forces, leading to a potentially higher risk of ACL injury.Study Design:Cross-sectional study; Level of evidence, 3.Methods:We mathematically modeled the posterior curvature of the lateral tibial plateau in 64 patients with ACL injuries and 68 matched controls. Using sagittal magnetic resonance imaging scans of the knee, points on the articular cartilage of the posterolateral tibial plateau were selected and curve-fitted to a power function (y = a × xn). For coefficient a and coefficient n, both variables modulated the shape of the curve, where a larger magnitude represented an increase in slope steepness. Groups were compared using a Mann-Whitney test and α < .05.Results:There was a significant difference in surface geometry between the patients with ACL injuries and matched controls. The equation coefficients were significantly larger in the patients with ACL injuries: coefficient a (ACL injury, 0.9 vs control, 0.68; P < .0001) and coefficient n (ACL injury, 0.34 vs control, 0.30; P = .07). For coefficient a, there was a 78.9% sensitivity, 77.5% specificity, and odds ratio of 12.6 (95% CI, 5.5-29.0) for ACL injury using a cutoff coefficient a = .78.Conclusion:Patients with ACL injuries had a significantly greater posterolateral plateau slope. The steeper drop off may play a role in higher anterior translation forces, coupled with internal rotation torques on the knee in noncontact injury, which could increase ACL strain and predispose to ACL injury.

ARTICULAR CARTILAGE THICKNESS IN PEDIATRIC AND ADOLESCENT KNEES DECREASES WITH AGE AND SKELETAL MATURITY: IMPLICATIONS FOR OSTEOCHONDRAL GRAFTING PROCEDURES

Background:Quantifying native cartilage thickness in pediatric and adolescent knees can help match donor and recipient sites for articular cartilage restoration procedures such as osteochondral autograft transplantation (OATS) and osteochondral allograft transplantation (OCA).Hypothesis/Purpose:The purpose of the current study was to quantify articular cartilage thickness in pediatric and adolescent knees using magnetic resonance imaging (MRI). We hypothesized that cartilage thickness is inversely correlated with skeletal maturity and age.Methods:One hundred and twenty MRI scans were evaluated in a cohort of patients 9 to 18 years old without osteochondral lesions, chondral wear or pathology, intraarticular fractures, history of knee surgery, or inflammatory arthropathy. Measurements of articular cartilage thickness at the medial femoral condyle, lateral femoral condyle, lateral trochlea, and patella were made on axial, coronal, and sagittal MRI scans (Figure 1). Skeletal maturity was categorized as ‘open’, ‘closing’, or ‘closed’ based on the status of the proximal tibial and distal femoral growth plates. Descriptive statistics was used to evaluate cartilage thickness by age and sex. Independent samples t-test, analysis of variance (ANOVA), and linear regression were performed to investigate for associations with sex, skeletal maturity, and age.Results:On the femur, cartilage was thickest at the lateral trochlea with mean articular thickness of 4.2 ± 1.4 mm in males and 3.6 ± 1.3 mm in females (p=0.015) (Table 1). Skeletally immature patients with open physes had significantly thicker cartilage at the medial femoral condyle, lateral femoral condyle, and lateral trochlea compared to patients with closing and closed physes (Figure 2). Linear regression analysis also revealed a significant association between femoral cartilage thickness and age (Figure 3). Age explained 63% of the variance at the medial femoral condyle (B=6.1, p<0.001), 64% of the variance at the lateral femoral condyle (B=4.9, p<0.001), and 68% of the variance at the lateral trochlea (B=8.2, p<0.001) (Table 2). In contrast, cartilage thickness at the patella did not significantly vary by age, sex, or skeletal maturity (Figures 2 and 4).Conclusion:There is a strong inverse association between increasing age and cartilage thickness of the femoral condyles and lateral trochlea. In particular, pediatric knees demonstrate relatively thick cartilage at the lateral trochlea that decreases with age. This information will help surgeons understand recipient site anatomy and identify appropriate donor site tissue for articular cartilage restoration procedures such as OATS and OCA in children and adolescents.Tables:Table 1.Mean articular cartilage thickness of the femur and patellaCombined (n=120)Male(n=40)Female(n=60) p valueMedial femoral condyle3.2 ± 1.03.5 ± 1.02.9 ± 0.80.001Lateral femoral condyle2.8 ± 0.72.9 ± 0.72.7 ± 0.70.056Lateral trochlea3.9 ± 1.44.2 ± 1.43.6 ± 1.30.015Median ridge of patella4.2 ± 0.94.4 ± 0.94.1 ± 0.90.080Medial facet of patella4.7 ± 1.04.8 ± 1.04.6 ± 0.90.320Lateral facet of patella4.6 ± 0.84.7 ± 0.84.5 ± 0.80.185Table 2.Linear regression of articular cartilage thickness of the femur and patella by ageR2 B p valueMedial femoral condyle0.636.1<0.001Lateral femoral condyle0.644.9<0.001Lateral trochlea0.688.2<0.001Median ridge of patella0.024.80.090Medial facet of patella0.045.50.032Lateral facet of patella0.0014.50.741Figures:Figure 1.Measurements of patellofemoral articular cartilage thickness Measurements of articular cartilage thickness were made on (A) coronal, (B, C) sagittal, and (D) axial magnetic resonance imaging (MRI) of the knee. For the medial femoral condyle, cartilage thickness was measured at five regions: midpoint of the medial condyle (MFC) and midpoints of Cahill zones 1 (MID1), 2 (MID2), B (MIDB) and C (MIDC). Similarly, measurements of cartilage thickness of the lateral femoral condyle were made at the midpoint of the lateral condyle (LFC) and midpoints of Cahill zones 4 (MID4), 5 (MID5), B (MIDB), and C (MIDC). Measurement of the lateral trochlea was made at midpoint of Cahill zone A (MIDA). Measurements on the patella were made at the midpoint of the medial facet (MF), midpoint of the lateral facet (LF), and the median ridge (MR) on axial and sagittal MRI scans. Figure 2.Mean articular cartilage thickness of the femur and patella by growth plate statusFigure 3.Mean articular cartilage thickness of the femur by ageFigure 4.Mean articular cartilage thickness of the patella by age

Automatic Detection of a Standard Line for Brain Magnetic Resonance Imaging Using Deep Learning

Recently, deep learning technology has been applied to medical images. This study aimed to create a detector able to automatically detect an anatomical structure presented in a brain magnetic resonance imaging (MRI) scan to draw a standard line. A total of 1200 brain sagittal MRI scans were used for training and validation. Two sizes of regions of interest (ROIs) were drawn on each anatomical structure measuring 64 × 64 pixels and 32 × 32 pixels, respectively. Data augmentation was applied to these ROIs. The faster region-based convolutional neural network was used as the network model for training. The detectors created were validated to evaluate the precision of detection. Anatomical structures detected by the model created were processed to draw the standard line. The average precision of anatomical detection, detection rate of the standard line, and accuracy rate of achieving a correct drawing were evaluated. For the 64 × 64-pixel ROI, the mean average precision achieved a result of 0.76 ± 0.04, which was higher than the outcome achieved with the 32 × 32-pixel ROI. Moreover, the detection and accuracy rates of the angle of difference at 10 degrees for the orbitomeatal line were 93.3 ± 5.2 and 76.7 ± 11.0, respectively. The automatic detection of a reference line for brain MRI can help technologists improve this examination.

Cauda Equina Occupation Ratio as a New Imaging Parameter for the Evaluation of Spinal Dural Arteriovenous Fistulae

Because spinal dural arteriovenous fistulae (SDAVF) are rare and their clinical presentation is nonspecific, they are often overlooked during diagnostic evaluations. Typical magnetic resonance imaging (MRI) findings are intramedullary T2-weighted signal hyperintensity and perimedullary flow voids. There are few reports on the characteristic signs of the cauda equina. We assessed the significance of a new imaging parameter, the cauda equina occupation ratio (CEOR), for the evaluation of SDAVF. We retrospectively analyzed the clinical charts and radiological findings of 20 SDAVF patients treated at our institutions. We evaluated sagittal T2-weighted MRI scans and assessed the CEOR, the occupation ratio of the cauda equina compared to the sagittal diameter of the corresponding lumbar spinal canal. The controls were 21 age- and sex-matched subjects. Of the 20 SDAVF, 10 were at the thoracic and 10 at the lumbar spine. There was no significant difference between the preoperative CEOR and the spinal level of the fistulae or the neurological signs. On preoperative MRI scans, the mean CEOR was 56.0 ± 7.8; postoperatively, it was 37.1 ± 7.4 (P= 0.000). The preoperative CEOR was significantly larger in SDAVF patients than in the controls (P= 0.000); postoperatively, it was smaller than in the controls (P= 0.14). The preoperative CEOR was larger in patients with SDAVF than in the controls. It normalized after successful occlusion of the fistula. Our findings indicate that the CEOR is a useful parameter for the pre- and postoperative evaluation of SDAVF.

Why Does Large Venous Pouch Thrombose after Cerebral Arteriovenous Shunts Embolization?

Why Does Large Venous Pouch Thrombose after Cerebral Arteriovenous Shunts Embolization?

Surgical Treatment of Malignant Pheochromocytomas in Spine

Surgical Treatment of Malignant Pheochromocytomas in Spine

Determining gender by taking measurements from magnetic resonance images of the patella

BackgroundA key step in making a positive identification in forensic medicine is the establishment of a biological profile, which involves determining factors such as gender, age, ancestry, and stature. The goal of this study was to determine if gender could be established by taking various measurements of the patella taken from magnetic resonance imaging (MRI) images and analyzing the variations by gender. MethodsThe sample group consisted of 220 patients (110 male and 110 female) whose patella were measured using MRI images of their left knee. Reasons for exclusion were any previous surgery, patella bipartite variation, any fracture in the patella due to trauma or findings of mass or infection. Three measurements – transverse length (TP), craniocaudal length (CC) and anteroposterior length (APP) – were taken off T2-weighted axial and sagittal MRI scans. The program SPSS (Version 21.0) was used to make a descriptive analysis, independent t-test and discriminative analysis. ResultsIt was found possible to determine gender with an accuracy rate of 91% for females and 87% for males. Since measurements were made individually the accuracy for gender estimation is lower than that seen in other methods. ConclusionThe findings are important in that they show that it is possible to determine gender with a high degree of accuracy using just a few measurements taken from the patella.

Can a Single Sagittal Magnetic Resonance Imaging Slice Represent Whole Fatty Infiltration in Chronic Rotator Cuff Tears at the Supraspinatus?

BackgroundThis study aimed to investigate whether fatty infiltration (FI) measured on a single sagittal magnetic resonance imaging (MRI) slice can represent FI of the whole supraspinatus muscle.MethodsThis study retrospectively reviewed the MRIs of 106 patients (age 50–79 years) divided into three rotator cuff tear-size groups: medium, large, and massive. Fat mass and muscle mass on all T1-weighted sagittal MRI scans (FA and MA) were measured. Of the total MRI scans, the Y-view was defined as the most lateral image of the junction of the scapular spine with the scapular body on the oblique sagittal T1-weighted image. Fat mass and muscle mass seen on this Y-view single slice were recorded as F1 and M1, respectively. Fat mass and muscle mass were also assessed on MRI scans lateral and medial to the Y-view. The means of fat mass and muscle mass on these three slices were recorded as F3 and M3, respectively. Average FI ratios (fat mass/muscle mass) of the three assessment methods (F1/M1, FA/MA, and F3/M3) were compared. Intraclass correlation coefficients (ICCs) were calculated for inter- and intraobserver reliability.ResultsICCs showed higher reliability (> 0.8) for all measurements. F1/M1 values were not statistically different from FA/MA and F3/M3 values (p > 0.05), except in males with medium and large tears. F3/M3 and FA/MA were not statistically different. The difference between F1/M1 and FA/MA did not exceed 2%.ConclusionsA single sagittal MRI slice can represent the whole FI in chronic rotator cuff tears, except in some patient groups. We recommend measurement of FI using a single sagittal MRI slice, given the effort required for repeated measurements.