Time-efficient combined morphologic and quantitative joint MRI based on clinical image contrasts -- An exploratory in-situ study of standardized cartilage defects

OBJECTIVES: Quantitative MRI techniques such as T2 and T1$\rho$ mapping are beneficial in evaluating cartilage and meniscus. We aimed to evaluate the MIXTURE (Multi-Interleaved X-prepared Turbo-Spin Echo with IntUitive RElaxometry) sequences that provide morphologic images with clinical turbo spin-echo (TSE) contrasts and additional parameter maps versus reference TSE sequences in an in-situ model of human cartilage defects. MATERIALS AND METHODS: Prospectively, standardized cartilage defects of 8mm, 5mm, and 3mm diameter were created in the lateral femora of 10 human cadaveric knee specimens (81$\pm$10 years, nine male/one female). Using a clinical 3T MRI scanner and knee coil, MIXTURE sequences combining (i) proton-density weighted fat-saturated (PD-w FS) images and T2 maps and (ii) T1-weighted images and T1$\rho$ maps were acquired before and after defect creation, alongside the corresponding 2D TSE and 3D TSE reference sequences. Defect delineability, bone texture, and cartilage relaxation times were quantified. Inter-sequence comparisons were made using appropriate parametric and non-parametric tests. RESULTS: Overall, defect delineability and texture features were not significantly different between the MIXTURE and reference sequences. After defect creation, relaxation times increased significantly in the central femur (for T2) and all regions combined (for T1$\rho$). CONCLUSION: MIXTURE sequences permit time-efficient simultaneous morphologic and quantitative joint assessment based on clinical image contrasts. While providing T2 or T1$\rho$ maps in clinically feasible scan time, morphologic image features, i.e., cartilage defect delineability and bone texture, were comparable between MIXTURE and corresponding reference sequences.Comment: 12 pages (main body), 3 tables, 6 figure

신 실질 질환에서 정량적 자기공명영상의 유용성: 쥐 만성 신 질환 모델을 이용한 실험연구

학위논문 (박사) -- 서울대학교 대학원 : 의과대학 의학과, 2021. 2. 조정연.연구 목적 아데닌을 이용한 만성 신질환 실험동물 모델을 이용하여 만성 신질환의 실질섬유화를 평가함에 있어 정량적 자기공명영상의 유용성을 검증하고 적절한 이미지 바이오 마커를 제안하고자 한다. 연구 방법 총 16마리의 수컷 위스타 (Wistar) 쥐를 세 개의 그룹으로 나누어 – 대조군 (n=7), 만성신질환 실험군 1 (n=5), 만성신질환 실험군2 (n=4)- 실험군의 경우, 각각 0.25% 아데닌을 3주 또는 6주 기간 동안 노출시켜 만성 신질환을 유발한 뒤, 9.4T 소동물 MRI 기기를 이용하여 확산강조영상 (DWI), T1ρ (T1 rho), T2*맵 (mapping), 생체 내 MR 분광분석(in vivo 1H-MRS) 검사를 시행하였다. 영상 검사 후, 적출한 신장의 반정량적 조직병리학적 분석을 시행하여 만성 신질환 병리 분석 결과와 영상 분석을 통해 얻은 정량적 파라 미터 값 사이의 통계적 유의성은 검증하였다. 연구 결과 정상신을 가진 대조군과 비교하였을 때, 아데닌 노출 기간에 따라 만성 신질환의 유의한 조직병리학적 변화가 관찰되었다. 확산계수(ADC), T1ρ (T1 rho) 값은 만성신질환 실험군에서 유의한 증가를 보였다. 신장 피질(CO)과 바깥 수질(OM)에서 측정한 확산계수, T1ρ값의 유의한 증가를 보였다. 확산계수 값은 노출 기간에 따라 증가하는 경향이 있었고, T1ρ (T1 rho) 값은 3주 동안 노출시킨 만성신질환 실험군 1에서 증가하다가 6주 실험군에서는 감소하는 경향을 보였다. MR 분광분석 대사 물 가운데, 신 수질에서 얻은 myo-inositol (Ins)-glycine (Gly) 대비 콜린 (choline) 화합물 (glycerophosphorylcholine (GPC)-choline (Cho)-phosphatidylcholine (PC)의 비율이 만성신질환 실험군에서 유의하게 낮은 소견을 보였다. 결론 우리는 이 실험을 통해 정량적 MR 영상은 비 침습적인 방법으로 만성 신질환을 진단하고 평가하는 도구로서 잠재적 가능성을 확인하였다. 특히 T1ρ은 신실질의 섬유화를 정량적으로 평가하는데 적합한 정량적 MR 시퀀스 파라 미터임을 확인하였다. 생체 내 MR 분광분석을 이용한 대사물의 변화 추적이 만성 신의 osmolality변화를 반영하는 비침습적 방법이 될 수 있음을 확인하였다.Objective This study aimed to validate the usefulness of quantitative multiparametric magnetic resonance imaging (MRI) sequence parameters and suggest the suitable spectroscopic metabolites in the evaluation of parenchymal fibrosis using an experimental animal model of chronic kidney disease (CKD) by long-term adenine intake. Materials and Methods Experimental adenine intake in rats induces renal dysfunction due to the deposition of 2,8-dihydroxyadenine crystals in the renal parenchyma. This pathophysiologic progression resembles that of human CKD. A total of 16 male Wistar rats were analyzed. They were divided into three groups: control (n = 7), CKD1 (n = 5), and CKD2 (n = 4). The CKD groups were kept under the 3- or 6-week term intake of 0.25% adenine. According to group assignment, quantitative MRI sequences, including diffusion-weighted image, T1ρ (T1 rho), T2* mapping, and in vivo MR spectroscopy (1H-MRS), were performed using a 9.4T animal MR scanner. A semiquantitative histopathologic analysis for renal fibrosis was conducted. Comparative analyses of quantitative MR values measured from anatomic regions of kidneys between groups were performed. Results Compared to the control group, significant histopathologic changes were observed in CKD groups according to periods. The apparent diffusion coefficient (ADC) and T1 (T1 rho) values were significantly increased in all CKD groups compared with those in the control group. The differences in values measured from the cortex and outer medulla were significant between all CKD groups and control group. The total ADC values tended to increase according to periods. The T1ρ (T1 rho) values were increased in the CKD1 group and decreased in the CKD2 group. Among MRS metabolites acquired from each region, the ratio of glycerophosphorylcholine–choline–phosphatidylcholine signals to myo-inositol–glycine signals collected from voxels located at medulla region was significantly lower in the CKD groups than in the control group (0.17 vs. 0.456, P = 0.0448). Conclusion Quantitative MRI sequences could be a noninvasive assessment modality in the diagnosis and evaluation of CKD. In particular, T1ρ may be a suitable MR sequence parameter to assess renal parenchymal fibrosis in a quantitative manner. Moreover, monitoring the change in common metabolites using MRS may reflect the alteration of osmolality in the renal medulla in CKD.Abstract in English ----------------------------------------------- 1 Contents ------------------------------------------------------------ 4 List of tables and figures ---------------------------------------- 5 Introduction ------------------------------------------------------- 8 Material & Methods -------------------------------------------- 10 Results ------------------------------------------------------------- 16 Discussion --------------------------------------------------------- 25 References --------------------------------------------------------- 35 Abstract in Korean ---------------------------------------------- 42Docto

Relationship Between Quantitative MRI Biomarkers and Patient-Reported Outcome Measures After Cartilage Repair Surgery: A Systematic Review.

Background:Treatment of articular cartilage injuries remains a clinical challenge, and the optimal tools to monitor and predict clinical outcomes are unclear. Quantitative magnetic resonance imaging (qMRI) allows for a noninvasive biochemical evaluation of cartilage and may offer advantages in monitoring outcomes after cartilage repair surgery. Hypothesis:qMRI sequences will correlate with early pain and functional measures. Study Design:Systematic review; Level of evidence, 3. Methods:A PubMed search was performed with the following search terms: knee AND (cartilage repair OR cartilage restoration OR cartilage surgery) AND (delayed gadolinium-enhanced MRI OR t1-rho OR T2 mapping OR dgemric OR sodium imaging OR quantitative imaging). Studies were included if correlation data were included on quantitative imaging results and patient outcome scores. Results:Fourteen articles were included in the analysis. Eight studies showed a significant relationship between quantitative cartilage imaging and patient outcome scores, while 6 showed no relationship. T2 mapping was examined in 11 studies, delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) in 4 studies, sodium imaging in 2 studies, glycosaminoglycan chemical exchange saturation transfer (gagCEST) in 1 study, and diffusion-weighted imaging in 1 study. Five studies on T2 mapping showed a correlation between T2 relaxation times and clinical outcome scores. Two dGEMRIC studies found a correlation between T1 relaxation times and clinical outcome scores. Conclusion:Multiple studies on T2 mapping, dGEMRIC, and diffusion-weighted imaging showed significant correlations with patient-reported outcome measures after cartilage repair surgery, although other studies showed no significant relationship. qMRI sequences may offer a noninvasive method to monitor cartilage repair tissue in a clinically meaningful way, but further refinements in imaging protocols and clinical interpretation are necessary to improve utility

Effet du marathon sur les signes précurseurs de gonarthrose: analyse critique de la littérature : travail de Bachelor

Introduction : Le marathon a gagné en popularité au cours des dernières années. Il existe de nombreuses questions quant aux bénéfices de cette forme de course à pied notamment sur le système locomoteur. L’impact de la course de longue distance sur les articulations est sujet à controverses. Objectif : Evaluer si le marathon augmente le risque d’apparition de signes précurseurs de gonarthrose. Méthode : Nous avons consulté les bases de données Pubmed, SportDiscus, Cinahl plus with full text, The Cochrane Library, PEDro et Kiné doc. La stratégie de recherche utilisée a réuni des mots clés autour de trois axes : le sport, la pathologie et la localisation c’est-à-dire la course à pied de longue distance, l’arthrose et le genou. Nos outcomes étaient l’intégrité du cartilage, l’œdème de la moelle osseuse, l’effusion intra articulaire, les ménisques, les ligaments collatéraux et croisés. Cinq articles de design avant-après, avec ou sans groupe contrôle, ont été retenus. La qualité des articles a été évaluée avec l’échelle MINORS. Résultats : Les résultats concernant le cartilage, l’œdème, l’effusion et les ménisques sont controversés. Ces données tendent à indiquer une absence d’effet sur le genou. Aucune différence n’a été remarquée sur les ligaments. Conclusion : Il est difficile d’apporter une conclusion tranchée quant à l’effet dumarathon sur les signes précurseurs d’arthrose. D’après notre revue de la littérature, le marathon ne semble pas néfaste pour l’articulation du genou. D’autres études sont nécessaires afin de vérifier cette tendance

Cardiac Magnetic Resonance Imaging of the Myocardium in Chronic Kidney Disease

Early stages of chronic kidney disease (CKD) are often underdiagnosed, while their deleterious effects on the cardiovascular (CV) system are already at work. Thus, the assessment of early CV damage is of crucial importance in preventing major CV events. Myocardial fibrosis is one of the major consequences of progressive CKD, as it may lead to reentry arrhythmias and long-term myocardial dysfunction predisposing to sudden death and/or congestive heart failure. Subclinical myocardial fibrosis, with a potential key role in the development of uraemic cardiac disease, can be measured and characterised by appropriate cardiac magnetic resonance (CMR) techniques. Fibrosis detection was initially based on the contrast agent gadolinium, due to the superiority in sensitivity and accuracy of contrast-based methods in fibrosis assessment relative to native techniques. However, the severe consequences of gadolinium administration in uraemia (nephrogenic systemic fibrosis) have forced practitioners to re-evaluate the methodology. In the present overview, we review the possible contrast-based and contrast agent-free CMR techniques, including native T1 relaxation time, extracellular volume and global longitudinal strain measurement. The review also summarises their potential clinical relevance in CKD patients based on recently published studies