Inter-rater and inter-session reliability of lumbar paraspinal muscle composition in a mobile MRI device

Objective: To assess the reliability of measurements of paraspinal muscle transverse relaxation times (T2 times) between two observers and within one observer on different time points. Methods: 14 participants (9f/5m, 33 ± 5 years, 176 ± 10 cm, 73 ± 12 kg) underwent 2 consecutive MRI scans (M1,M2) on the same day, followed by 1 MRI scan 13–14 days later (M3) in a mobile 1.5 Tesla MRI. T2 times were calculated in T2 weighted turbo spin-echo-sequences at the spinal level of the third lumbar vertebrae (11 slices, 2 mm slice thickness, 1 mm interslice gap, echo times: 20, 40, 60, 80, 100 ms) for M. erector spinae (ES) and M. multifidius (MF). The following reliability parameter were calculated for the agreement of T2 times between two different investigators (OBS1 & OBS2) on the same MRI (inter-rater reliability, IR) and by one investigator between different MRI of the same participant (intersession variability, IS): Test–Retest Variability (TRV, Differences/Mean*100); Coefficient of Variation (CV, Standard deviation/Mean*100); Bland–Altman Analysis (systematic bias = Mean of the Differences; Upper/Lower Limits of Agreement = Bias+/−1.96*SD); Intraclass Correlation Coefficient 3.1 (ICC) with absolute agreement, as well as its 95% confidence interval. Results: Mean TRV for IR was 2.6% for ES and 4.2% for MF. Mean TRV for IS was 3.5% (ES) and 5.1% (MF). Mean CV for IR was 1.9 (ES) and 3.0 (MF). Mean CV for IS was 2.5% (ES) and 3.6% (MF). A systematic bias of 1.3 ms (ES) and 2.1 ms (MF) were detected for IR and a systematic bias of 0.4 ms (ES) and 0.07 ms (MF) for IS. ICC for IR was 0.94 (ES) and 0.87 (MF). ICC for IS was 0.88 (ES) and 0.82 (MF). Conclusion: Reliable assessment of paraspinal muscle T2 time justifies its use for scientific purposes. The applied technique could be recommended to use for future studies that aim to assess changes of T2 times, e.g. after an intense bout of eccentric exercises.

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Hydrocephalus in dogs: a review

Veterinární Medicína ◽

10.17221/6698-vetmed ◽

2013 ◽

Vol 58 (No. 2) ◽

pp. 73-80 ◽

Cited By ~ 5

Author(s):

P. Przyborowska ◽

Z. Adamiak ◽

M. Jaskolska ◽

Y. Zhalniarovich

Keyword(s):

Clinical Symptoms ◽

Imaging Techniques ◽

Spin Echo ◽

Brain Area ◽

Volume Ratio ◽

Diagnostic Methods ◽

Slice Thickness ◽

Advantages And Disadvantages ◽

Mri Scans ◽

The Brain

Hydrocephalus is a multifactoral disorder that was rarely diagnosed in dogs until the availability of advanced imaging techniques in veterinary practice. This article reviews recent advances in the understanding of canine hydrocephalus including pathogenesis, clinical symptoms, diagnostic methods, and treatment solutions. The advantages and disadvantages of USG, RTG, CT and MRI as advanced diagnostic methods are discussed. For now Low-field Magnetic Resonance Imaging is the most useful tool in investigating hydrocephalus. The recommended sequences for MRI are T1-weighting images Spin echo, Field echo 3D with TR 380–750 ms, TE 12–25 ms, slice thickness 1–6 mm and with an interslice gap of 0–2 mm. The evaluation of cerebral ventricular system morphology in obtained MRI scans involves measuring the height, area and volume of the brain and lateral ventricles. The results are classified as normal state if the ratio of ventricular height to the brain height is above 14%, the ratio of ventricular area to the brain area amounts to above 7%, and the ventricular to brain volume ratio is above 5%. However, there are still problems relating to inter- and intrabreed comparison among examined dogs. Treatment solutions in hydrocephalus are also discussed in this review. The medical treatment of hydrocephalus aims to decrease CSF production and is based on using acetazolamide, furosemide and prednisone. Surgical management aims to place the ventriculoperitoneal shunt for CSF flow control. Postsurgical complications are also described in this review.  

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An emerging technology: Nuclear magnetic resonance microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010706x ◽

1988 ◽

Vol 46 ◽

pp. 1000-1001

Author(s):

M.J. Hennessy ◽

E. Kwok

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Relaxation Times ◽

Basic Research ◽

Local Environment ◽

Magnetic Resonance Images ◽

Nmr Microscopy ◽

Mri Scans ◽

Temperature Relaxation ◽

Nuclear Magnetic

Much progress in nuclear magnetic resonance microscope has been made in the last few years as a result of improved instrumentation and techniques being made available through basic research in magnetic resonance imaging (MRI) technologies for medicine. Nuclear magnetic resonance (NMR) was first observed in the hydrogen nucleus in water by Bloch, Purcell and Pound over 40 years ago. Today, in medicine, virtually all commercial MRI scans are made of water bound in tissue. This is also true for NMR microscopy, which has focussed mainly on biological applications. The reason water is the favored molecule for NMR is because water is,the most abundant molecule in biology. It is also the most NMR sensitive having the largest nuclear magnetic moment and having reasonable room temperature relaxation times (from 10 ms to 3 sec). The contrast seen in magnetic resonance images is due mostly to distribution of water relaxation times in sample which are extremely sensitive to the local environment.

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Evaluation of malignant effusions using MR-based T1 mapping

Scientific Reports ◽

10.1038/s41598-021-86632-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

D. Kuetting ◽

J. Luetkens ◽

A. Faron ◽

A. Isaak ◽

U. Attenberger ◽

...

Keyword(s):

T1 Mapping ◽

Ex Vivo ◽

Diagnostic Yield ◽

Spin Echo ◽

Relaxation Times ◽

Inversion Recovery ◽

Malignant Effusions ◽

Mapping Techniques ◽

Set Up ◽

Post Hoc

AbstractOur aim was to investigate the diagnostic yield of rapid T1-mapping for the differentiation of malignant and non-malignant effusions in an ex-vivo set up. T1-mapping was performed with a fast modified Look-Locker inversion-recovery (MOLLI) acquisition and a combined turbo spin-echo and inversion-recovery sequence (TMIX) as reference. A total of 13 titrated albumin-solutions as well as 48 samples (29 ascites/pleural effusions from patients with malignancy; 19 from patients without malignancy) were examined. Samples were classified as malignant-positive histology, malignant-negative histology and non-malignant negative histology. In phantom analysis both mapping techniques correlated with albumin-content (MOLLI: r = − 0.97, TMIX: r = − 0.98). MOLLI T1 relaxation times were shorter in malignancy-positive histology fluids (2237 ± 137 ms) than in malignancy-negative histology fluids (2423 ± 357 ms) as well as than in non-malignant-negative histology fluids (2651 ± 139 ms); post hoc test for all intergroup comparisons: < 0.05. ROC analysis for differentiation between malignant and non-malignant effusions (malignant positive histology vs. all other) showed an (AUC) of 0.89 (95% CI 0.77–0.96). T1 mapping allows for non-invasive differentiation of malignant and non-malignant effusions in an ex-vivo set up.

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Lateral Trochlear Inclination Angle: Measurement via a 2-Image Technique to Reliably Characterize and Quantify Trochlear Dysplasia

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120958415 ◽

2020 ◽

Vol 8 (10) ◽

pp. 232596712095841

Author(s):

Sheeba M. Joseph ◽

Chris Cheng ◽

Matthew J. Solomito ◽

J. Lee Pace

Keyword(s):

Measurement Technique ◽

Trochlear Dysplasia ◽

Intraclass Correlation ◽

Single Image ◽

Image Measurement ◽

Mri Scan ◽

Morphologic Characteristics ◽

Mri Scans ◽

Image Technique ◽

Dejour Classification

Background: Trochlear dysplasia (TD) is a risk factor for patellar instability (PI). The Dejour classification categorizes TD but has suboptimal reliability. Lateral trochlear inclination (LTI) is a quantitative measurement of trochlear dysplasia on a single axial magnetic resonance imaging (MRI) scan. Hypothesis: A modified LTI measurement technique using 2 different axial MRI scans that reference the most proximal aspect of the trochlear cartilage on 1 image and the fully formed posterior condyles on the second image would be as reliable as and significantly different from the single-image measurement technique for LTI. Further, the 2-image LTI would adequately represent overall proximal trochlear morphologic characteristics. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Patients aged 9 to 18 years treated for PI between 2014 and 2017 were identified. The Dejour classification was radiographically determined. Single-image LTI was measured on a single axial MRI scan at the most proximal aspect of visible trochlear cartilage. A 2-image LTI was measured from 2 separate MRI scans: 1 at the most proximal aspect of trochlear cartilage and the second at the fully formed posterior condyles. This 2-image LTI was repeated at 3 subsequent levels (the first measurement is referred to as LTI-1; repeated measurements are LTI-2, LTI-3, and LTI-4, moving distally). In total, 65 patients met the inclusion criteria, and 30 were randomly selected for reliability analysis. Results: Inter- and intrarater reliability trended toward more variability for single-image LTI (intraclass correlation coefficient [ICC], 0.86 and 0.88, respectively) than for 2-image LTI (ICC, 0.97 and 0.96, respectively). The Dejour classification had lower intra- and interrater reliability (ICC, 0.31 and 0.73, respectively). Average single-image LTI (9.2° ± 12.6°) was greater than average 2-image LTI-1 (4.2° SD ± 11.9°) ( P = .0125). Single-image LTI classified 60% of patients with PI as having TD, whereas the 2-image LTI classified 71% as having TD. The 2-image LTI was able to capture 91% of overall proximal trochlear morphologic characteristics. Conclusion: LTI has higher reliability when performed using a 2-image measurement technique compared with single-image LTI and Dejour classification. The strong correlation between 2-image LTI and average LTI shows that 91% of TD is represented on the most proximal axial image. Because the single-image measurement appears to underestimate dysplasia, previously described thresholds should be reexamined using this 2-image technique to appropriately characterize TD.

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Myocardial Tissue Characterization By T2 Mapping in Thalassemia Major

Blood ◽

10.1182/blood-2020-134591 ◽

2020 ◽

Vol 136 (Supplement 1) ◽

pp. 27-28

Author(s):

Alessia Pepe ◽

Nicola Martini ◽

Rita Borrello ◽

Vincenzo Positano ◽

Laura Pistoia ◽

...

Keyword(s):

Tissue Characterization ◽

Spin Echo ◽

T2 Mapping ◽

Relaxation Times ◽

Thalassemia Major ◽

Fast Spin Echo ◽

Myocardial Inflammation ◽

Healthy Population ◽

Myocardial Iron ◽

Magnetic Resonance Imaging Mri

Introduction.The presence of iron deposits results in a significant reduction in all magnetic resonance imaging (MRI) relaxation times (T1, T2 and T2*). In the clinical setting the T2* technique is the method of choice for cardiac iron quantification and it has revolutionized the management of patients with hemoglopinopathies. Purpose.To compare myocardial T2 against T2* in patients with thalassemia major (TM) for myocardial iron characterization. Methods.133 TM patients (79 females, 38.4±11.3 years) enrolled in the Extension Myocardial Iron Overload in Thalassemia (eMIOT) Network were considered. T2 and T2* images were acquired, respectively, with multi-echo fast-spin-echo and gradient-echo sequences. Global heart T2 and T2* values were obtained by averaging the values in all 16 myocardial segments. The normal T2 range was established as mean±2 standard deviations on data acquired on 80 healthy volunteers (males: 48-56 ms and females: 50-57 ms). The lower limit of normal for global heart T2*, established on the same healthy population, was 32 ms. Results.A significant correlation was detected between global heart T2 and T2* values (R=0.577; P<0.0001) (Figure). Out of the 113 (84.9%) patients with a normal global heart T2* value, none had a decreased global heart T2 value, while 58 (51.3%) had an increased T2 value. Out of the 20 patents with a decreased global heart T2* value, only 10 (50%) had also a reduced T2 value. Conversely, 9 (45.0%) had a normal global heart T2 value and one (4.5) showed an increased T2 value. The 59 patients with increased global heart T2 value were significantly older than the remaining patients (40.8±10.5 vs 36.4±11.6 years; P=0.019) Conclusion.All patients with decreased T2 value had also a decreased T2* value and in half of the patients iron load was undetected by T2, suggesting that T2 mapping does not offer any advantage in terms of sensitivity for MIO assessment. However, more than half of TM patients had an increased T2 value, thus may be caused by the presence of myocardial inflammation and/or edema. So, T2 mapping could reveal subclinical myocardial involvement in TM patients. Figure Disclosures Pistoia: Chiesi Farmaceutici S.p.A.:Other: speakers' honoraria.Meloni:Chiesi Farmaceutici S.p.A.:Other: speakers' honoraria.

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Characterization of 3-Dimensional Printing and Casting Materials for use in Magnetic Resonance Imaging Phantoms at 3 T

Journal of Research of the National Institute of Standards and Technology ◽

10.6028/jres.125.028 ◽

2020 ◽

Vol 125 ◽

Cited By ~ 1

Author(s):

B. E. Yunker ◽

K. F. Stupic ◽

J. L. Wagner ◽

S. Huddle ◽

R. Shandas ◽

...

Keyword(s):

Magnetic Resonance Imaging ◽

Tensile Strength ◽

Magnetic Resonance ◽

3D Printing ◽

Spin Echo ◽

Relaxation Times ◽

Patient Specific ◽

Resonance Imaging ◽

Fused Deposition ◽

Imaging Phantoms

Imaging phantoms are used to calibrate and validate the performance of magnetic resonance imaging (MRI) systems. Many new materials have been developed for additive manufacturing (three-dimensional [3D] printing) processes that may be useful in the direct printing or casting of dimensionally accurate, anatomically accurate, patient-specific, and/or biomimetic MRI phantoms. The T1, T2, and T2* spin relaxation times of polymer samples were tested to discover materials for use as tissue mimics and structures in MRI phantoms. This study included a cohort of polymer compounds that was tested in cured form. The cohort consisted of 101 standardized polymer samples fabricated from: two-part silicones and polyurethanes used in commercial casting processes; one-part optically cured polyurethanes used in 3D printing; and fused deposition thermoplastics used in 3D printing. The testing was performed at 3 T using inversion recovery, spin echo, and gradient echo sequences for T1, T2, and T2*, respectively. T1, T2, and T2* values were plotted with error bars to allow the reader to assess how well a polymer matches a tissue for a specific application. A correlation was performed between T1, T2 , T2* values and material density, elongation, tensile strength, and hardness. Two silicones, SI_XP-643 and SI_P-45, may be usable mimics for reported liver values; one silicone, SI_XP-643, may be a useful mimic for muscle; one silicone, SI_XP-738, may be a useful mimic for white matter; and four silicones, SI_P-15, SI_GI-1000, SI_GI-1040, and SI_GI-1110, may be usable mimics for spinal cord. Elongation correlated to T2 (p = 0.0007), tensile strength correlated to T1 (p = 0.002), T2 (p = 0.0003), and T2* (p = 0.003). The 80 samples not providing measurable signal with T1, T2, T2* relaxation values too short to measure with the standard sequences, may be useful for MRI-invisible fixturing and medical devices at 3 T.

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Valid and Reliable Barbell Velocity Estimation Using an Inertial Measurement Unit

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18179170 ◽

2021 ◽

Vol 18 (17) ◽

pp. 9170

Author(s):

Steffen Held ◽

Ludwig Rappelt ◽

Jan-Philip Deutsch ◽

Lars Donath

Keyword(s):

Inertial Measurement Unit ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Velocity Estimation ◽

Measurement Unit ◽

Systematic Bias ◽

Validity And Reliability ◽

Inertial Measurement ◽

Intraclass Correlation Coefficients ◽

Reliability Indicators

The accurate assessment of the mean concentric barbell velocity (MCV) and its displacement are crucial aspects of resistance training. Therefore, the validity and reliability indicators of an easy-to-use inertial measurement unit (VmaxPro®) were examined. Nineteen trained males (23.1 ± 3.2 years, 1.78 ± 0.08 m, 75.8 ± 9.8 kg; Squat 1-Repetition maximum (1RM): 114.8 ± 24.5 kg) performed squats and hip thrusts (3–5 sets, 30 repetitions total, 75% 1RM) on two separate days. The MCV and displacement were simultaneously measured using VmaxPro® and a linear position transducer (Speed4Lift®). Good to excellent intraclass correlation coefficients (0.91 < ICC < 0.96) with a small systematic bias (p < 0.001; ηp2 < 0.50) for squats (0.01 ± 0.04 m·s−1) and hip thrusts (0.01 ± 0.05 m·s−1) and a low limit of agreement (LoA < 0.12 m·s−1) indicated an acceptable validity. The within- and between-day reliability of the MCV revealed good ICCs (0.55 < ICC < 0.91) and a low LoA (<0.16 m·s−1). Although the displacement revealed a systematic bias during squats (p < 0.001; ηp2 < 0.10; 3.4 ± 3.4 cm), no bias was detectable during hip thrusts (p = 0.784; ηp2 < 0.001; 0.3 ± 3.3 cm). The displacement showed moderate to good ICCs (0.43 to 0.95) but a high LoA (7.8 to 10.7 cm) for the validity and (within- and between-day) reliability of squats and hip thrusts. The VmaxPro® is considered to be a valid and reliable tool for the MCV assessment.

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ANALISIS PERBEDAAN CITRA MRI BRAIN PADA SEKUENT1SE DAN T1FLAIR

SINERGI ◽

10.22441/sinergi.2015.3.007 ◽

2015 ◽

Vol 19 (3) ◽

pp. 206

Author(s):

Nursama Heru Apriantoro ◽

Christianni Christianni

Keyword(s):

White Matter ◽

Gray Matter ◽

Spin Echo ◽

Spinal Fluid ◽

Inversion Recovery ◽

Field Of View ◽

Slice Thickness ◽

Weighted Image ◽

Mri Brain ◽

Fluid Attenuated Inversion Recovery

MRI adalah bagian dari ilmu kedokteran untuk mediagnosa kelainan organ dengan memanfaatkan medan magnet dan pergerakan proton atom hidrogen. Salah satu pemeriksaan MRI adalah pemeriksaan brain. Pemeriksaan MRI brain dapat dilakukan T1 weighted image Spin Echo (T1 SE) atau T1 Fluid Attenuated Inversion Recovery (T1 FLAIR). Kajian dilakukan untuk menentukan perbedaan T1 SE dan T1 FLAIR dari segi citra berdasarkan nilai Rasio Signal terhadap Noise (SNR) dengan MRI GE Type Signa HD xt 1.5 Tesla. Penelitian menggunakan pendekatan kuantitatif. 20 pasien telah diambil pada pemeriksaan MRI brain pada potongan axial, dengan parameter T1 SE potongan axial dengan parameter Time Repetition (TR) 700 ms, Time Echo (TE) 20 ms, Field of View (FOV) 240 mm, Slice Thickness 5,0 mm, Spacing 1,0 mm, Number of Excitations (NEX) 1, Phase 224, dan total slice 20. T1 FLAIR parameter TR 3000 ms, TE 13,9 ms, TI 920 ms, FOV 240 mm, slice thickness 5,0 mm, spacing 1,0 mm, NEX 1, phase 224, dan total slice 20. SNR dihitung pada anatomi brain meliputi CSF (Cerebro Spinal Fluid), White Matter dan Gray Matter. Hasil penelitian kedua sequence tersebut menunjukkan bahwa sequence T1 SE lebih baik daripada sequence T1 FLAIR.

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NIMG-40. ROBUST MODALITY-AGNOSTIC SKULL-STRIPPING IN PRESENCE OF DIFFUSE GLIOMA: A MULTI-INSTITUTIONAL STUDY

Neuro-Oncology ◽

10.1093/neuonc/noz175.710 ◽

2019 ◽

Vol 21 (Supplement_6) ◽

pp. vi170-vi170 ◽

Cited By ~ 1

Author(s):

Siddhesh Thakur ◽

Jimit Doshi ◽

Sung Min Ha ◽

Gaurav Shukla ◽

Aikaterini Kotrotsou ◽

...

Keyword(s):

Human Performance ◽

Ground Truth ◽

Accurate Solution ◽

Test Subject ◽

Slice Thickness ◽

Diffuse Glioma ◽

Similarity Coefficients ◽

Unseen Data ◽

Skull Stripping ◽

Mri Scans

Abstract BACKGROUND Skull-stripping describes essential pre-processing in neuro-imaging, directly impacting subsequent analyses. Existing skull-stripping algorithms are typically developed and validated only on T1-weighted MRI scans without apparent gliomas, hence may fail when applied on neuro-oncology scans. Furthermore, most algorithms have large computational footprint and lack generalization to different acquisition protocols, limiting their clinical use. We sought to identify a practical, generalizable, robust, and accurate solution to address all these limitations. METHODS We identified multi-institutional retrospective cohorts, describing pre-operative multi-parametric MRI modalities (T1,T1Gd,T2,T2-FLAIR) with distinct acquisition protocols (e.g., slice thickness, magnet strength), varying pre-applied image-based defacing techniques, and corresponding manually-delineated ground-truth brain masks. We developed a 3D fully convolutional deep learning architecture (3D-ResUNet). Following modality co-registration to a common anatomical template, the 3D-ResUNet was trained on 314 subjects from the University of Pennsylvania (UPenn), and evaluated on 91, 152, 25, and 29 unseen subjects from UPenn, Thomas Jefferson University (TJU), Washington University (WashU), and MD Anderson (MDACC), respectively. To achieve robustness against scanner/resolution variability and utilize all modalities, we introduced a novel “modality-agnostic” training approach, which allows application of the trained model on any single modality, without requiring a pre-determined modality as input. We calculate the final brain mask for any test subject by applying our trained modality-agnostic 3D-ResUNet model on the modality with the highest resolution. RESULTS The average(±stdDev) dice similarity coefficients achieved for our novel modality-agnostic model were equal to 97.81%+0.8, 95.59%+2.0, 91.61%+1.9, and 96.05%+1.4 for the unseen data from UPenn, TJU, WashU, and MDACC, respectively. CONCLUSIONS Our novel modality-agnostic skull-stripping approach produces robust near-human performance, generalizes across acquisition protocols, image-based defacing techniques, without requiring pre-determined input modalities or depending on the availability of a specific modality. Such an approach can facilitate tool standardization for harmonized pre-processing of neuro-oncology scans for multi-institutional collaborations, enabling further data sharing and computational analyses.

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Patellar Malalignment Is Associated With Patellofemoral Lesions and Cartilage Relaxation Times After Hamstring Autograft Anterior Cruciate Ligament Reconstruction

The American Journal of Sports Medicine ◽

10.1177/0363546520930713 ◽

2020 ◽

Vol 48 (9) ◽

pp. 2242-2251

Author(s):

Tzu-Chieh Liao ◽

Alejandro G. Morales Martinez ◽

Valentina Pedoia ◽

Benjamin C. Ma ◽

Xiaojuan Li ◽

...

Keyword(s):

Lateral Displacement ◽

Spin Echo ◽

Cruciate Ligament ◽

Relaxation Times ◽

Fast Spin Echo ◽

Healthy Controls ◽

Resonance Imaging ◽

Anterior Cruciate ◽

Fast Spin ◽

And Cartilage

Background: There is growing evidence suggesting a link between patellofemoral joint (PFJ) osteoarthritis in anterior cruciate ligament (ACL)–reconstructed knees and altered joint alignment. Purpose: To determine whether patellar alignment differs between participants with and without ACL reconstruction (ACLR) and to identify possible associations between patellar alignment and PFJ osteoarthritis features over 3 years. Study Design: Cohort study; Level of evidence, 2. Methods: A total of 37 participants with ACLR (sex, 23 male; mean ± SD age, 28.1 ± 7.4 years) and 20 healthy controls (13 male; 30.4 ± 4.8 years) participated. Patients underwent magnetic resonance imaging: (1) sagittal T2-weighted fat-saturated fast spin echo images to calculate patellar alignment, (2) sagittal 3-dimensional intermediate-weighted fast spin echo Cube sequence for clinical morphological grading (modified Whole-Organ Magnetic Resonance Imaging Score [WORMS]), and (3) sagittal combined T1ρ/T2 mapping sequence for performing voxel-based relaxometry. Patellar alignment of the ACLR knees were assessed at 6 months (baseline). One-way analysis of variance was used to compare patellar alignment among the ACLR (at 6 months), contralateral, and control knees. Within the ACLR group, a logistic regression model was used to identify if patellar alignment measures at baseline were risk factors for worsening of PFJ structural changes over 3 years. Statistical parametric mapping was used to evaluate the longitudinal associations between patellar alignment and cartilage relaxation times at 3 years. Results: When compared with control knees, ACLR knees exhibited a laterally and anteriorly displaced patella ( P = .045 and P = .041), less flexion ( P = .031), and less lateral spin ( P = .012). Furthermore, excessive lateral displacement was a significant predictor of worsening of WORMS ( P = .050). Lateral displacement was positively correlated with increased T1ρ and T2 in the patellar and trochlear cartilage at 3 years. Patellar lateral spin revealed similar negative findings. Conclusion: Participants with ACLR exhibited a laterally and anteriorly displaced patella, less flexion, and less lateral spin when compared with healthy controls. Excessive patellar lateral displacement was the strongest predictor to the development of PFJ osteoarthritis features longitudinally.

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