Overall Survival Prediction in Stereotactic Radiosurgery Patients with Glioblastoma Via a Deep-Learning Approach

PURPOSE/OBJECTIVE(S)

Accurate and automated early survival prediction is critical for glioblastoma (GBM) patients as their poor prognosis requires timely treatment decision-making. We have developed a deep learning (DL)-based GBM overall survival (OS) prediction model based on a multi-institutional public dataset using only pre-operative basic structural multi-parametric magnetic resonance images (MRIs). The purpose of this study is to evaluate this DL-based OS prediction model with an institutional stereotactic radiosurgery (SRS) clinical trial dataset.

MATERIALS/METHODS

The task of this study is to classify GBM patients into 3 OS classes: long-survivors (>15 months), mid-survivors (between 10 and 15 months) and short-survivors (< 10 months). The proposed OS prediction model is an ensemble of a ResNet-based classifier and a K-NN classifier. The ResNet-based classifier is trained in a Siamese fashion to explore inter-class differences. During testing, training sample features are implemented with a K-NN classifier to ensemble with the ResNet-based classifier. A public dataset from Medical Image Computing and Computer Assisted Intervention (MICCAI) Brain Tumor Segmentation (BraTS) challenge 2020 (235 patients) were used for model establishing and initial validation. Then the validated model was evaluated on 19 GBM patients from an institutional SRS clinical trial. Each data entry consists of pre-operative basic structural multi-parametric MRIs and survival days, as well as patient ages for BraTS data and basic clinical characteristics for institutional data. GBM sub-regions, including contrast-enhancing tumor, peri-tumoral edema, and necrotic/non-enhancing tumor core, were segmented in the multi-parametric MRIs by an in-house DL model for both datasets. The OS prediction model was trained on 90% of the segmented BraTS data and validated on the rest 10%, then further evaluated on the institutional data. The model performance was assessed by prediction accuracy (ACC) and the area under the curve (AUC).

RESULTS

For this 3-class OS classification task, our DL-based prediction model achieved an ACC of 65.22% and an AUC of 0.81 on the BraTS dataset compared with the top-ranked result from the BraTS challenge 2020 (Rank 1st: ACC 61.7%), and an ACC of 52.63% and an AUC of 0.69 on the institutional dataset. Further analysis of the institutional dataset found that the predicted OS class had a statistically significant correlation with treatment volume (p = 0.012) and age (p = 0.006), which matches the analysis that the patients' ground truth OS class is statistical significantly correlated with treatment volume (p = 0.045).

CONCLUSION

Our DL-based OS prediction model for GBM using basic structural multi-parametric pre-operative MRIs has demonstrated promising performance in both public and institutional dataset with minimal manual processing requirements. This OS prediction model can be potentially applied to assist timely clinical decision-making.

Magnetic Susceptibility of Andreev Bound States in Superfluid ^{3}He-B

Nuclear magnetic resonance measurements of the magnetic susceptibility of superfluid ^{3}He imbibed in anisotropic aerogel reveal anomalous behavior at low temperatures. Although the frequency shift clearly identifies a low-temperature phase as the B phase, the magnetic susceptibility does not display the expected decrease associated with the formation of the opposite-spin Cooper pairs. This susceptibility anomaly appears to be the predicted high-field behavior corresponding to the Ising-like magnetic character of surface Andreev bound states within the planar aerogel structures.

Injectable carbon nanotube-functionalized hydrogel as a tool for cardiac tissue engineering

Background/Introduction

Heart failure (HF) is an expensive major public health problem in the United States and around the world (1). The current treatments for HF are aimed at reducing symptoms, slowing disease progression, and reducing mortality and not aimed at repairing heart muscle or restoring function. Furthermore, even with these treatments, approximately half of patients with HF will die within 5 years of diagnosis (2). Cardiac transplantation remains the only definitive treatment for those affected with end-stage HF, but availability of donor hearts remains a major limitation (3).

Purpose

The ability of the adult heart to regenerate cardiomyocytes (CMs) lost after injury is limited, generating interest in developing tissue engineering therapies to avoid progression towards HF. Rigid carbon nanotubes (CNTs) scaffolds have been used to improve CMs viability, proliferation, and maturation (4), but require undesirable invasive surgeries for implantation. To overcome this limitation, we engineered an injectable reverse thermal gel (RTG) functionalized with CNTs (RTG-CNT) that transitions from a liquid-solution to a gel-based matrix shortly after reaching body temperature allowing for a liquid-based delivery rapidly followed by a stable-gel localization (5).

Methods and results

Here we show experimental evidences the RTG-CNT hydrogel, used as a three-dimensional (3D) niche to culture human induced pluripotent stem cells (hiPSC)-CMs, promotes hiPSC-CMs alignment and elongation with increased Cx43 localization and improved contraction function when compared with traditional two-dimensional (2D) fibronectin controls and plain 3D RTG system without CNTs. Moreover, the short-term (4-week) biocompatibility of the RTG-CNT hydrogel was also assessed in a mouse model (intracardial injection). The results confirmed that the RTG-CNT hydrogel is well tolerated by the cardiac tissue.

Conclusion

Our results indicated that the injectable RTG-CNT hydrogel has the potential to be used as a minimally invasive tool for cardiac tissue engineering efforts.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): NATIONAL HEART, LUNG, AND BLOOD (NHLBI) INSTITUTE

Dysregulation of immune cell and cytokine signaling correlates with clinical outcomes in myelodysplastic syndrome (MDS)

OBJECTIVES

Myelodysplastic syndromes (MDS) are characterized by ineffective hematopoiesis. Although hypomethylating agents (HMA) have improved survival in higher-risk MDS, most patients eventually succumb to progressive disease. Utilizing samples collected prospectively from three MDS clinical trials, we analyzed genetic and immunological biomarkers and correlated them with clinical outcomes.

METHODS

154 samples were analyzed from 133 de novo MDS patients for T-cell and myeloid cell immunophenotyping and gene expression analysis. Treatments were with HMA or immunomodulatory drug (IMiD) alone or in combination.

RESULTS

We observed differences in immune cell subsets between lower and higher risk IPSS groups with NKT cells, MDSCs, intermediate-proinflammatory and non-classical monocytes being higher in the latter group while naïve CD4+ T-cells were reduced. Intermediate-proinflammatory monocytes were increased in non-responders and those failing to achieve at least a hematological improvement. Pro-inflammatory NKT cells were increased at diagnosis for patients failing to derive clinical benefit after 12 months of treatment. Gene expression analysis of paired bone marrow (BM) colony-forming units (CFUs) from diagnosis and 4 cycles post-treatment confirmed that genes involved in cytokine signaling were downregulated in C4 normal colonies.

CONCLUSIONS

These findings support the central roles of dysregulation in innate immunity and inflammatory signaling in the pathogenesis of MDS which correlated with clinical outcomes post-treatment.

Thyroid surgery during coronavirus-19 pandemic phases I, II and III: lessons learned in China, South Korea, Iran and Italy

OBJECTIVE

We compared demographic and clinic-pathological variables related to the number of surgeries for thyroid conditions or for cancer, morbidity, and fine needle aspiration (FNA) practices among Covid19 pandemic phases I, II, III and the same seasonal periods in 2019.

METHODS

The prospective database of the Division of Thyroid Surgery, China-Japan Union Hospital of Jilin University, Changchun, China was used for this study. Covid19 emergency levels were stratified according to the World Health Organization: phase I (January 25-February 25, 2020), phase II (February 26-March 19), phase III (March 20-April 20).

RESULTS

There were fewer outpatient FNAs and surgeries in 2020 than in 2019. There were no thyroid surgeries during phase I. There were also fewer surgeries for cancer with a significant reduction of advanced stage cancer treatments, mainly stage T1b N1a in phase II and T3bN1b in phase III. Operative times and postoperative stays were significantly shorter during the pandemic compared to our institutional baseline. In phase III, vocal cord paralysis (VCP) increased to 4.3% of our baseline numbers (P = 0.001). There were no cases of Covid19-related complications during the perioperative period. No patients required re-admission to the hospital.

CONCLUSION

The Covid19 outbreak reduced thyroid surgery patient volumes. The decrease of Covid19 emergency plans contributed to unexpected outcomes (reduction of early stage cancer treatment, decreased operative times and hospital stays, increased VCP rate).

Identification of Pistacia-associated flexivirus 1, a putative mycovirus of the family Gammaflexiviridae, in the mastic tree (Pistacia lentiscus) transcriptome

In this study, we identified the genome sequence of the novel virus Pistacia-associated flexivirus 1 (PAFV1), a putative member of the mycovirus family Gammaflexiviridae (the order Tymovirales), via analysis of a transcriptome dataset for the mastic tree (Pistacia lentiscus, the family Anacardiaceae). PAFV1 was predicted to have three open reading frames (ORFs): ORF1, encoding a replicase (REP) with RNA-dependent RNA polymerase activity; ORF2, a movement protein (MP); and ORF3, a hypothetical protein. The PAFV1 REP sequence showed high similarity to those of three known members of the family Gammaflexiviridae i.e., Entoleuca gammaflexivirus 1 (EnFV1), Entoleuca gammaflexivirus 2 (EnFV2), and Botrytis virus F (BVF). A genome contig of the fungus Monosporascus cannonballus also contained a sequence of an endogenous virus similar to that of PAFV1. Sequence comparison and phylogenetic analysis indicated that PAFV1, EnFV1, and the endogenous virus of M. cannonballus formed a distinct subgroup (apart from EnFV2 and BVF), and may be the founding members of a novel genus in the family Gammaflexiviridae. Notably, MP sequences of PAFV1/EnFV1 showed similarity to the MP sequences of the mycovirus group called tobamo-like mycoviruses (an unassigned taxon), implying that genomic recombination occurred between members of the family Gammaflexiviridae and tobamo-like mycoviruses. Since PAFV1 is phylogenetically related to mycoviruses, PAFV1 may also be a mycovirus that infected a fungus associated with the mastic tree sample, which is evidenced by the presence of fungal ribosomal RNA sequences in the mastic tree transcriptome. Thus, the PAFV1 genome sequence may be useful in elucidating the genome evolution of Gammaflexiviridae and tobamo-like mycoviruses. Keywords: Pistacia-associated flexivirus 1; Gammaflexiviridae; mycovirus, mastic tree.

Clinical features of subungual melanoma according to the extent of Hutchinson's nail sign: a retrospective single-centre study

BACKGROUND

Hutchinson's nail sign (HS) is among the diagnostic criteria for subungual melanoma (SUM). However, there is minimal evidence supporting the overall clinical significance of HS in SUM.

OBJECTIVES

To identify clinicopathological features of SUM according to the extent of HS.

METHODS

Retrospective cohort study was performed with consecutive SUM patients at a single centre from January 2006 to December 2017. The extent of HS was defined by the number of affected nail folds (range 0-4). Comparison groups were organized as follows: patients with HS (affecting ≥1 nail folds) vs. without HS; patients with HS affecting ≥2 nail folds vs. HS affecting <2 nail folds; patients with HS affecting ≥3 nail folds vs. HS affecting <3 nail folds. Clinicopathological characteristics of SUM were compared between the groups.

RESULTS

Sixty-one SUM patients were included. Forty-six (75.4%) exhibited HS; 22 (47.8%) on a toe and 24 (52.2%) on a finger. In multivariate analysis, nail destruction [hazard ratio (HR), 10.00; 95% confidence interval (CI), 2.61-38.30; P = 0.001] was significantly associated with the presence of HS and amputation was significantly associated with HS affecting ≥2 nail folds (HR, 4.75; 95% CI, 1.36-16.61; P = 0.015). High T stage (HR, 1.85; 95% CI, 1.20-2.85; P = 0.005, Fig. 2) was significantly associated with HS appearing in ≥3 nail folds.

CONCLUSION

Besides its value of detecting SUM, HS provides useful clinical information. The number of nail folds exhibiting HS could be a useful clinical clue for planning therapeutic strategies for SUM.

TEK is a novel prognostic marker for clear cell renal cell carcinoma

OBJECTIVE

Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer. However, effective therapeutics for ccRCC are lacking. Novel biomarkers could provide critical information when determining prognoses for patients with ccRCC. In this study, we sought to determine if the expression of receptor tyrosine kinase (TEK) could be a potential novel prognostic biomarker for ccRCC. TEK, originally identified as an endothelial cell-specific receptor, plays an important role in the modulation of vasculogenesis and remodeling. Altered TEK expression has been observed in tumor tissues (e.g., oral squamous cell carcinomas, leukemia) and breast, gastric and thyroid cancers. However, the role of TEK in ccRCC remains unknown.

PATIENTS AND METHODS

Differential TEK expression between non-metastatic (stage M0) and metastatic (stage M1) ccRCC patient cohorts was determined from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC). Furthermore, TEK expression was assessed as a prognostic factor using the time-dependent area under the curve (AUC) of Uno's C-index, the AUC value of the receiver operating characteristics (ROC) at 5 years, Kaplan-Meier survival curves and multivariate analyses.

RESULTS

A Kaplan-Meier curve analysis revealed that the downregulation of TEK expression was associated with a poor prognosis for patients with ccRCC with good discrimination (p<0.0001 and p=0.0044 for the TGCA and ICGC cohorts, respectively). Analyses of C-indices and receiver operating characteristic AUC values further support this discriminative ability. Moreover, multivariate analyses showed the prognostic significance of TEK expression levels (p<0.001).

CONCLUSIONS

Although additional clinical investigations will be needed, our results suggest that TEK is a potential biomarker for ccRCC.

A Tabletop Persistent-Mode, Liquid Helium-Free 1.5-T MgB2 "Finger" MRI Magnet: Construction and Operation of a Prototype Magnet

This paper presents results of construction and operation of a persistent-mode, liquid-helium-free, small-scale prototype magnet for the development of a tabletop 1.5-T "finger" MRI system for osteoporosis screening. The prototype magnet, composed of 2 MgB2 coils, one superconducting joint, and a persistent-current switch (PCS) built from a portion of one coil, was wound with a one continuous ~80-m long unreacted and monofilament MgB2 wire and then reacted. The test magnet was charged successfully and generated the estimated target field of 1.75 T at 5 K with the proposed PCS operation. During initial persistent-mode, the field was slightly decayed due to the index dissipation of the joint; thereafter it sustained the persistent field of 1.7 T for 35 h. The test results validated the joint resistance of < 1.2 × 10-11 as well as the proposed approach involving the PCS coil circuit model.

A novel Waikavirus (the family Secoviridae) genome sequence identified in rapeseed (Brassica napus)

The genome sequence of a novel species of the genus Waikavirus (the family Secoviridae), which we named Brassica napus RNA virus 1 (BnRV1), was identified in a rapeseed (Brassica napus) transcriptome dataset. The BnRV1 genome was 12,293 nucleotides long followed by a poly(A) tail. Two open reading frames (ORFs), called ORF1 and ORFX, were predicted. The larger ORF, ORF1, encodes a polyprotein of 3,471 amino acids and the smaller ORF, ORFX, overlaps ORF1 and encodes an 87 aa long protein of unknown function. The BnRV1 ORF1 polyprotein was predicted to undergo proteolytic processing to yield seven mature proteins, including an RNA-dependent RNA polymerase and three distinct coat proteins. The ORF1 and ORFX proteins share sequence similarities with the respective proteins of viruses in the genus Waikavirus, including the bellflower vein chlorosis virus, rice tungro spherical virus, and maize chlorotic dwarf virus. A phylogenetic tree inferred from a conserved segment of the polyproteins of several Secoviridae viruses confirmed that BnRV1 is a novel species of the genus Waikavirus. The BnRV1 genome sequence identified in this study may be useful for the study of waikavirus biology and waikavirus-derived diseases. Keywords: Brassica napus RNA virus 1; Waikavirus; Secoviridae; rapeseed.

Blastacervulus metrosideri sp. nov. leaf spot on Metrosideros excelsa in New Zealand

A leaf-spotting fungal pathogen common on Metrosideros excelsa in New Zealand is described here as Blastacervulus metrosideri sp. nov. It has previously been identified in the New Zealand literature as Leptomelanconium sp. and as Staninwardia breviuscula. The choice of genus for this new species is supported by a phylogeny based on ITS and LSU sequences. It is phylogenetically close to several morphologically similar Eucalyptus leaf spotting pathogens.

Abstract P2-09-07: Preoperative pembrolizumab (Pembro) with radiation therapy (RT) in patients with operable triple-negative breast cancer (TNBC)

Background: Radiation therapy (RT) induces immune-mediated cell death and could generate a rich supply of tumor antigens if administered in the pre-operative, curative-intent setting. The addition of PD-1 mediated checkpoint blockade to pre-operative RT could thus, generate robust anti-tumor immune responses, induce long-term tumor-specific memory, and ultimately, improve cure rates. This study aims to establish the safety of pre-operative pembrolizumab (pembro)-mediated immune modulation with a RT “boost” equivalent in patients with operable triple negative breast cancer (TNBC) for whom lumpectomy and adjuvant RT are planned (NCT03366844). Serial research biopsies permit interrogation of conventional biomarkers including tumor infiltrating lymphocytes (TILs) and novel immune correlates as potential predictors of response to pembro alone versus pembro with RT.

Methods: Ten women with operable, primary TNBC &gt;2cm for whom breast-conserving therapy is planned are being enrolled in this single-institution pilot study. Study treatment consists of 1 cycle of pre-operative pembro (200 mg IV) alone, followed 3 weeks later by a RT boost (24 Gy/3 fractions) to the primary breast tumor concurrently with pembro (+/- 5 days). Curative-intent, standard-of-care, neoadjuvant chemotherapy (NAC) or breast-conserving surgery is then undertaken within 8 weeks of study enrollment (i.e. within 5 weeks of pembro #2). Adjuvant RT is administered per standard-of-care after surgery, but without a boost dose. Research blood and fresh tumor biopsies are obtained at baseline and after cycles 1 and 2 of pembro. Co-primary endpoints are: 1) safety/tolerability, as defined by the number of patients who do not necessitate a delay in standard-of-care chemotherapy or surgery and 2) change in TIL score. Secondary endpoints include safety/toxicity up to 19 weeks after study enrollment, pCR rates and disease-free survival. Correlative analysis will include single-cell RNA sequencing of the tumor immune infiltrate and multispectral immunohistochemistry

Results: Seven patients enrolled between 12/19/17 and 7/1/18. As of 7/1/18, 5 patients have completed the experimental pembro/RT phase of the trial and are currently completing standard-of-care NAC; 1 patient is currently being treated in the experimental pembro/RT phase; and 1 patient with a cT2N0 tumor at baseline achieved a pathologic complete response (pCR, ypT0/Tis ypN0) after completing the experimental pembro/RT phase followed by anthracycline- and taxane-based NAC. No grade 3 or 4 toxicities have been observed during pembro/RT in the 6 patients completing the experimental phase to date. Three additional patients will be enrolled

Conclusions: This is the first trial of curative-intent, pre-operative checkpoint blockade with RT in breast cancer and the strategy appears to be well tolerated to date. At the time of presentation, safety, change in TIL score, and pCR rates for all patients completing the experimental and NAC phases of the study will be reported.

Citation Format: McArthur HL, Basho R, Shiao SL, Park D, Mita M, Chung A, Arnold B, Martin C, Dang C, Karlan S, Knott S, Giuliano A, Ho A. Preoperative pembrolizumab (Pembro) with radiation therapy (RT) in patients with operable triple-negative breast cancer (TNBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-09-07.

Identification of a novel plant amalgavirus (Amalgavirus, Amalgaviridae) genome sequence in Cistus incanus

Amalgaviridae is a family of double-stranded, monosegmented RNA viruses that are associated with plants, fungi, microsporidians, and animals. A sequence contig derived from the transcriptome of a eudicot, Cistus incanus (the family Cistaceae; commonly known as hoary rockrose), was identified as the genome sequence of a novel plant RNA virus and named Cistus incanus RNA virus 1 (CiRV1). Sequence comparison and phylogenetic analysis indicated that CiRV1 is a novel species of the genus Amalgavirus in the family Amalgaviridae. The CiRV1 genome contig has two overlapping open reading frames (ORFs). ORF1 encodes a putative replication factory matrix-like protein, while ORF2 encodes a RNA-dependent RNA polymerase (RdRp) domain. An ORF1+2 fusion protein, which functions in viral RNA replication, is produced by a +1 programmed ribosomal frameshifting (PRF) mechanism. A +1 PRF motif UUU_CGU, which matches the conserved amalgavirus +1 PRF consensus sequence UUU_CGN, was found at the boundary of CiRV1 ORF1 and ORF2. Comparison of 25 amalgavirus ORF1+2 fusion proteins revealed that only three different positions within a 13-amino acid segment were recurrently used at the boundary, possibly being selected so as not to interfere with correct folding and function of the fusion protein. CiRV1 is the first virus found to be associated with the Cistus species and may be useful for studying amalgaviruses.

Novel Divavirus (the family Betaflexiviridae) and Mitovirus (the family Narnaviridae) species identified in basil (Ocimum basilicum)

Transcriptome data obtained from a plant sample often contain a large number of reads that are derived from associated RNA virus genomes that were co-isolated during RNA preparation. These virus-derived reads can be assembled into a novel plant RNA genome sequence. Here, a basil (Ocimum basilicum) transcriptome dataset was analyzed to identify two new RNA viruses, which were named Ocimum basilicum RNA virus 1 (ObRV1) and Ocimum basilicum RNA virus 2 (ObRV2). A phylogenetic analysis of the ObRV1 RNA-dependent RNA polymerase (RdRp) motif indicated that ObRV1 is a novel species of the genus Divavirus of the family Betaflexiviridae. ObRV1 is the fourth divavirus species to be identified. The ObRV2 RdRp motif showed sequence similarity to viruses of the genus Mitovirus of the family Narnaviridae, which infect fungal mitochondria. Although most of the known mitoviruses do not produce a functional RdRp using the plant mitochondrial genetic code, the ObRV2 encodes a full-length RdRp using both the fungal and plant mitochondrial genetic codes.

Determination of the Mechanisms that Cause Sarcopenia through cDNA Microarray

BACKGROUND

Sarcopenia, the aging-related deterioration of skeletal muscle, is a disease that is directly associated with quality of life. Given the trend of an increasing aging population worldwide, the prevention of aging-related diseases such as sarcopenia has become ever more important and urgent.

OBJECTIVE

To identify potential therapeutic targets for this disease.

METHODS

we used a bioinformatics approach of combining cDNA microarray analysis and protein-protein interaction prediction.

RESULTS

We found 673 significant differentially expressed genes (128 upregulated and 545 downregulated) in sarcopenia patients of over 60 years of age. Most of the upregulated genes were involved in metabolic processes such as the PPAR signaling pathway. In particular, FABP4, PLIN1, and ADIPOQ were related to fatty acid and lipid metabolism. Some of the downregulated genes were located in the mitochondrial matrix. Additionally, through the protein interaction network analysis, we found two key molecules (MAP1LC3B and HSP90AB1) that were associated with autophagy.

CONCLUSIONS

These results suggest that mitochondrial dysfunction and lipid metabolism are associated with sarcopenia.

Genome sequence of a distinct watermelon mosaic virus identified from ginseng (Panax ginseng) transcriptome

Watermelon mosaic virus (WMV) is a member of the genus Potyvirus, which is the largest genus of plant viruses. WMV is a significant pathogen of crop plants, including Cucurbitaceae species. A WMV strain, designated as WMV-Pg, was identified in transcriptome data collected from ginseng (Panax ginseng) root. WMV-Pg showed 84% nucleotide sequence identity and 91% amino acid sequence identity with its closest related virus, WMV-Fr. A phylogenetic analysis of WMV-Pg with other WMVs and soybean mosaic viruses (SMVs) indicated that WMV-Pg is a distinct subtype of the WMV/SMV group of the genus Potyvirus in the family Potyviridae.

Diagnostic and prognostic value of delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) in early osteoarthritis of the hip

BACKGROUND

Delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) can detect glycosaminoglycan loss in the acetabular cartilage of asymptomatic individuals with cam morphology. The aims of this study were to explore the relationship between cam morphology and dGEMRIC values, and to explore whether baseline dGEMRIC can predict the development of radiographic hip osteoarthritis.

METHODS

Prospective cohort (SibKids) study with clinical, radiographic, and MRI assessment at baseline and five-year follow-up (n = 34). The dGEMRIC values of cartilage regions were correlated with measures of cam morphology. Receiver operating characteristic (ROC) analysis was applied to baseline variables to predict radiographic loss of joint space width.

RESULTS

Superolateral acetabular cartilage dGEMRIC values were significantly lower in participants with cam morphology (P < 0.001), defined as an alpha angle greater than 60°. There was a negative correlation between alpha angle and the dGEMRIC value of adjacent acetabular cartilage. This relationship was strongest superoanteriorly (r = -0.697 P < 0.001). There was a positive correlation between baseline dGEMRIC and the magnitude of joint space width narrowing (r = 0.398 P = 0.030). ROC analysis of combined baseline variables (positive impingement test, alpha angle, dGEMRIC ratio) gave an Area Under the Curve (AUC) of 0.75 for predicting joint space width narrowing greater than 0.5 mm within 5 years.

CONCLUSIONS

The size and position of cam morphology determines the severity and location of progressive cartilage damage, supporting the biomechanical aetiology of femoroacetabular impingement. Baseline dGEMRIC is able to predict the development of radiographic osteoarthritis. Compositional MRI offers the potential to identify patients who may benefit from early intervention to prevent the development of osteoarthritis.