MRI T2 Mapping Research Articles

Spatial distribution and temporal progression of T2 relaxation time values in knee cartilage prior to the onset of cartilage lesions – data from the Osteoarthritis Initiative (OAI)

To investigate compositional changes of knee cartilage at the site of newly appearing cartilage lesions and the surrounding cartilage 1-4 years prior to lesion onset using quantitative T2-measurements. Fifty-seven cartilage plates with newly appearing cartilage lesions from 45 knees (cases) and 52 plates from 26 control knees from the Osteoarthritis Initiative (OAI) cohort (controls) were evaluated. Using MRI T2-mapping, composition of local (the site of future lesions) and surrounding cartilage (remainder of the cartilage plate) was assessed 1-4 years prior to lesion onset. Analogous cartilage ROIs in control plates without cartilage lesions were assessed over 1-4 years. Mixed models were used to compare T2-means and change rates between local and surrounding cartilage within cases and controls, and to compare change rates in local and surrounding cartilage between cases and controls, adjusting for covariates. Four years prior to lesion onset, we found that local cartilage ROIs had higher T2-values compared to the surrounding cartilage. No such differences were found in control plates. In cases mean local T2-values were persistantly elevated compared to the surrounding cartilage prior to lesion onset reaching significance 1 year prior (+2.94ms, p=0.012). T2-values of the surrounding cartilage were also persistantly higher in cases compared to controls, reaching significance 2 years prior to lesion onset (+3.61ms, p=0.003). The findings of our study support the concept of compositional cartilage changes as a mechanism for cartilage degradation and that both diffuse and focal changes of cartilage composition within a cartilage plate precede the development of cartilage lesions.

Magnetic Resonance Imaging: A New Tool to Optimize the Prediction of Fetal Anemia?

Introduction: The false-positive rate in the prediction of fetal anemia is 10–15%. We investigated if a new, noninvasive MRI method used as a supplement to ultrasound could improve the prediction. Methods: Fetuses suspected of anemia and controls were scanned in a 1.5-tesla MRI scanner 1–4 times during pregnancy. Cases were scanned before and after intrauterine blood transfusion with a T1-mapping MRI sequence in a cross-section of the umbilical vein. Results: Inclusion of 8 cases and 11 controls resulted in 10 case scans (2 cases were included twice) and 33 control scans. In controls, the T1 relaxation time was 1,005–1,391 ms; in cases with severe anemia, 1,505–1,595 ms, moderate anemia 1,503–1,525 ms, and no/mild anemia 1,245–1,410 ms. After blood transfusions, values dropped to 1,123–1,288 ms. The mean value in moderate and severe anemic cases was 275 ms higher than in controls (95% CI 210–341 ms, p < 0.0001), and after blood transfusion it was comparable to controls (3 ms, 95% CI –62 to 68 ms, p = 0.934). A 1,450-ms cut-off would have identified all cases in need of blood transfusion with no false-positive cases. Conclusions: Our findings indicate a potential for this new MRI method to improve the prediction of fetal anemia as a supplement to ultrasound.

Monitoring Knee Biomechanics in Patients Undergoing Anterior Cruciate Ligament Reconstruction: How Joint Loading Affects Cartilage Quality

Rupture of anterior cruciate ligament (ACL) is a common injury, generally treated by reconstruction surgery. Despite good clinical outcomes, achieving a long-term success for this procedure is still a challenge: young patients could face in fact early degenerative processes, including knee osteoarthritis (OA). The altered biomechanics of the reconstructed joint could affect knee anatomical structures varying – for instance – the loads on the intra-articular cartilage, definitely inducing its degeneration. To better understand the factors that can compromise the long-term success of this procedure, this study investigated the ACL transtibial reconstruction effects on overall knee biomechanics and on articular cartilage, by integrating dynamic radiostereophotogrammetry, inferior limb multi-body modelling and MRI T2 mapping, in order to correlate knee joint loads to its physiopathological status

MRI gadolinium dosing on basis of blood volume.

Gadolinium-based contrast agents (GBCAs) for MRI are generally administrated in direct relationship to body weight. Instead, we propose a model for GBCA dosing on the basis of blood volume. The new method was tested by exploring the associations between MRI T1 mapping indices and weight in the MESA (Multi-Ethnic Study of Atherosclerosis. Empirically derived methods based on sex and body habitus were used to calculate blood volumes. GBCA dose (in mL) in blood (in L) was calculated as the injected volume divided by the blood volume (i.e., DBV). Of the 1219 participants with cardiac MRI T1 mapping, 845 studies had standard dose of 0.15 mmol/kg (cohort 1) and 166 studies had 30 mL of GBCA regardless of weight (cohort 2). We also created a specific cohort with similar DBV (N = 357; cohort 3). Postcontrast blood relaxation rate R1blood and DBV were significantly correlated (R = 0.641; P < 0.001). R1blood was significantly associated with weight in cohort 1 and 2, but the correlation coefficient was positive for cohort 1 and negative for cohort 2, indicating GBCA overdosing in cohort 1 and underdosing in cohort 2 in heavy relative to lean subjects. R1blood was not associated with weight in cohort 3. Simulated results demonstrated that less contrast should be administrated for heavy subjects compared to the conventional weight-based dose. GBCA dosing on the basis of blood volume could improve the efficacy and safety of contrast-enhanced MRI studies. This method could be implemented to standardize dose and augment precision in study comparisons.

A systematic review of the treatment of knee osteoarthritis with intraarticular injection of mesenchymal stem cells

Background: A wide array of treatment, both surgical and nonsurgical, exists for osteoarthritis (OA) of the knee. Injectable stem-cell therapy represents a minimally invasive and potentially efficacious treatment; however, there have been no level I studies conducted on this specific application of stem-cell therapy. The purpose of our review was to analyze, report, and summarize current topical data. Methods: A systematic review of the treatment of human knee OA with mesenchymal stem cells (MSCs) was performed by searching PubMed/Medline and Google Scholar. Non-human studies and studies involving additional procedures were excluded. Authors reviewed the studies individually, with the primary author deciding on inclusion. Results: Our search ultimately returned 10 studies that met the inclusion criteria. Nine of the ten studies used cultured autologous MSCs, five from bone marrow, three from subcutaneous fat, and one from peripheral blood. The remaining study used allogenic bone marrow MSCs. Radiographic analysis of cartilage quality via MRI T2 mapping showed increased type II collagen production in five studies. Outcome scores consistently showed pain reduction and improved function. No study reported significant adverse events related to stem-cell therapy. Conclusions: Current human studies evaluating the use of injected MSCs for knee OA demonstrated consistent improvement across several outcome scores, with no significant adverse findings. Level of Evidence: Level IV, systematic review of Level II-IV trials and studies.

The feasibility of synthetic MRI in breast cancer patients: comparison of T2 relaxation time with multiecho spin echo T2 mapping method.

To compare the T2 relaxation times acquired with synthetic MRI to those of multi-echo spin-echo sequences and to evaluate the usefulness of synthetic MRI in the clinical setting. From January 2017 to May 2017, we included 51 patients with newly diagnosed breast cancer, who underwent additional synthetic MRI and multiecho spin echo (MESE) T2 mapping sequences. Synthetic MRI technique uses a multiecho and multidelay acquisition method for the simultaneous quantification of physical properties such as T1 and T2 relaxation times and proton density image map. A radiologist with 9 years of experience in breast imaging drew region of interests manually along the tumor margins on two consecutive axial sections including the center of tumor mass and in the fat tissue of contralateral breast on both synthetic T2 map and MESE T2 map images. The mean T2 relaxation time of the cancer was 84.75 ms (± 15.54) by synthetic MRI and 90.35 ms (± 19.22) by MESE T2 mapping. The mean T2 relaxation time of the fat was 129.22 ms (± 9.53) and 102.11 ms (± 13.9), respectively. Bland-Altman analysis showed mean difference of 8.4 ms for the breast cancer and a larger mean difference of 27.8 ms for the fat tissue. Spearman's correlation test showed that there was significant positive correlation between synthetic MRI and MESE sequences for the cancer (r = 0.713, p < 0.001) and for the fat (r = 0.551, p < 0.001). The positive estrogen receptor and low histologic grade were associated with little differences between two methods (p = 0.02 and = 0.043, respectively). T2 relaxation times of breast cancer acquired with synthetic MRI showed positive correlation with those of MESE T2 mapping. Synthetic MRI could be useful for the evaluation of tissue characteristics by simultaneous acquisition of several quantitative physical properties. Synthetic MRI is useful for the evaluation of T2 relaxation times of the breast cancers.

T2 mapping MRI in prediction of Graves ophthalmopathy activity

Objective To explore the value of T2 mapping MRI in predicting Graves ophthalmopathy (GO) activity. Methods 74 patients with GO and 30 normal individuals underwent coronal T2 mapping MRI were analyzed prospectively from August 2010 to June 2013 in Beijing Tongren Hospital, Capital Medical University. All the GO patients met Mourits criterion, with hyperthyroidism history, and enlargement of extraocular muscles (EOMs) found by MRI. GO patients were grouped by CAS. Of which, 52 patients in CAS ≥ 3, 22 patients in CAS<3, 12 patients in CAS=0, and 10 patients in CAS=0 or 1. T2 values of EOMs (superior rectus muscle, inferior rectus muscle, medial rectus muscle, external rectus muscle and superior oblique muscle) were calculated. The differences of mean T2 values between two eyes, among EOMs, different CAS groups and controls were evaluated by paired-sample t test and one-way ANOVA, respectively. The correlation between maxT2 and CAS was conducted by Spearman rank correlation analysis in GO patients. The cut-off value of maxT2 in predicting GO activity was determined by ROC curve. Results There was no significant difference on T2 values between sides and among EOMs in control (P>0.05), while GO group showed significant difference (P<0.05) . T2 value increased by sequence of superior oblique muscle, external rectus muscle, superior rectus muscle, medial rectus muscle and inferior rectus muscle, failed to show significant difference between medial and superior rectus muscle (P=1.00). T2 value increased by sequence of normal control, CAS=0, CAS=1/2 and CAS≥ 3 group (P<0.05) . Spearman rank correlation revealed positive correlation between maxT2 and CAS (r=0.898, P<0.01). The cut-off value of maxT2 was 138.68 msec, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 63.5% (33/52), 90.9% (20/22), 94.3% (33/35), 51.3% (20/39), 71.6% (53/74), respectively. Conclusion T2 mapping MRI is valuable in predicting GO activity. Key words: Graves ophthalmopathy; Magnetic resonance imaging

T2 mapping MRI technique quantifies carotid plaque lipid, and its depletion after statin initiation, following acute myocardial infarction

Background & aimsA recently-validated, highly-sensitive T2 mapping magnetic resonance (MRI) technique accurately quantifies carotid plaque lipid. The aims of this study were to determine: (i) the extent of carotid plaque lipid in patients with acute coronary syndromes (ACS); (ii) the effects of initiation of high-intensity statin on plaque lipid content and (iii) whether plaque lipid content is related to standard or ‘functional’ blood lipid measurements. MethodsStatin naïve subjects presenting with ACS underwent carotid artery MRI at 3 T scanner to quantify plaque lipid. Patients were subsequently commenced on high dose statin as part of clinical care and underwent a second MRI after three months. Plaque composition was measured using objective semi-automated techniques. Results23 out of 24 patients had measurable lipid. Three months after statin initiation there was a significant reduction in carotid lipid percentage [from 10.3% (7.2–14.2) to 7.4% (5.4–10.0), p = 0.002] and a significant increase in fibrous percentage [from 83.3% ± 6.6–85.5% ± 4.8, p = 0.039]. None of the studied functional blood biomarkers were related to either baseline carotid plaque lipid content or its propensity to change with statin treatment. ConclusionsT2-mapping demonstrated depleted carotid plaque lipid following the initiation of high-intensity statin treatment. Standard or ‘functional’ blood biomarkers were dissociated from plaque lipid content or changes with treatment. These findings further reinforce the importance of disease characterisation over risk factor assessment. Subject to clinical trial findings, quantification of plaque lipid may provide the basis for an approach to identify patients suitable for intensive lipid reduction regimes.

Quantification of Liver Fibrosis at T1 and T2 Mapping with Extracellular Volume Fraction MRI: Preclinical Results.

Purpose To evaluate MRI T1 and T2 mapping with calculation of extracellular volume (ECV) for diagnosis and grading of liver fibrosis. Materials and Methods Different grades of fibrosis were induced in 60 male Sprague-Dawley rats by bile duct ligation (BDL) and carbon-tetrachloride (CCl4) intoxication. Portal pressure was measured invasively, whereas hepatic fibrosis was quantified by hydroxyproline content, Sirius red staining, and α smooth muscle actin staining. T1 values, T2 values, and ECV were assessed by using quantitative MRI mapping techniques. Results T1 values in animals 4 weeks after BDL were greater than in control animals (718 msec ± 74 vs 578 msec ± 33, respectively; P < .001). T2 values at 4 weeks were also greater in animals that underwent BDL than in control animals (46 msec ± 6 vs 29 msec ± 2, respectively; P < .001). Similar T1 and T2 findings were observed after CCl4 intoxication. ECV was greater in animals 4 weeks after BDL compared with control animals (31.3% ± 1.3 vs 18.2% ± 3.5, respectively; P < .001), with similar results after CCl4 intoxication. High correlations were found between ECV and hepatic hydroxyproline content (BDL: r = 0.68, P < .001; CCl4: r = 0.65, P < .001), Sirius red staining (BDL: r = 0.88, P < .001; CCl4: r = 0.82, P < .001), α smooth muscle actin staining (BDL: r = 0.70, P < .001; CCl4: r = 0.73, P < .001), and portal pressure (BDL: r = 0.54, P = .003; CCl4: r = 0.39, P = .043). Conclusion Elevation of T1 and T2 values and ECV was associated with severity of liver fibrosis and portal hypertension in an experimental animal model.

CEST MRI of sepsis-induced acute kidney injury.

Sepsis-induced acute kidney injury (SAKI) is a major complication of kidney disease associated with increased mortality and faster progression. Therefore, the development of imaging biomarkers to detect septic AKI is of great clinical interest. In this study, we aimed to characterize the endogenous chemical exchange saturation transfer (CEST) MRI contrast in the lipopolysaccharide (LPS)-induced SAKI mouse model and to investigate the use of CEST MRI for detecting such injury. We used a SAKI mouse model that was generated by i.p. injection of 10mg/kg LPS. The resulting kidney injury was confirmed by the elevation of serum creatinine and histology. MRI assessments were performed 24h after LPS injection, including CEST MRI at different B1 strengths (1, 1.8 and 3 μT), T1 mapping, T2 mapping and conventional magnetization transfer contrast (MTC) MRI. The CEST MRI results were analyzed using Z-spectra, in which the normalized water signal saturation (Ssat /S0 ) is measured as a function of saturation frequency. Substantial decreases in CEST contrast were observed at both 3.5 and-3.5ppm frequency offset from water at all B1 powers, with the most significant difference obtained at a B1 of 1.8 μT. The average Ssat /S0 differences between injured and normal kidneys were 0.07 (0.55±0.04 versus 0.62±0.04, P=0.0028) and 0.07 (0.50±0.04 versus 0.57±0.03, P=0.0008) for 3.5 and-3.5ppm, respectively. In contrast, the T1 and T2 relaxation times and MTC contrast in the injured kidneys did not show a significant change compared with the normal control. Our results showed that CEST MRI is more sensitive to the pathological changes in injured kidneys than the changes in T1 , T2 and MTC effect, indicating its potential clinical utility for molecular imaging of renal diseases.

Evaluation of articular cartilage following rotational acetabular osteotomy for hip dysplasia using T2 mapping MRI.

Rotational acetabular osteotomy (RAO) is one of the surgical treatments for acetabular dysplasia, and satisfactory results have been reported. We evaluated the postoperative changes of articular cartilage and whether the pre-operative condition of the articular cartilage influences the clinical results using T2 mapping MRI. We reviewed 31 hips with early stage osteoarthritis in 31 patients (mean age, 39.6years), including three men and 28 women who underwent RAO for hip dysplasia. Clinical evaluations including Japanese Orthopedic Association (JOA) score and Japanese Orthopedic Association Hip Disease Evaluation Questionnaire (JHEQ), and radiographical evaluations on X-ray were performed. Longitudinal qualitative assessment of articular cartilage was also performed using 3.0-T MRI with T2 mapping technique preoperatively, 6 months, and at 1 and 2years postoperatively. There was no case with progression of osteoarthritis. The mean JOA score improved from 70.1 to 93.4 points, the mean postoperative JHEQ score was 68.8 points, and radiographical data also improved postoperatively. We found that the T2 values of the cartilage at both femoral head and acetabulum increased at 6months on coronal and sagittal views. However, they significantly decreased 1 and 2years postoperatively. The T2 values of the center to anterolateral region of acetabulum negatively correlated with postoperative JHEQ score, particularly in pain score. This study suggests that biomechanical and anatomical changes could apparently cause decreased T2 values 1-2 years postoperatively compared with those preoperatively. Furthermore, preoperative T2 values of the acetabulum can be prognostic factors for the clinical results of RAO.

A vectorized Levenberg-Marquardt model fitting algorithm for efficient post-processing of cardiac T1 mapping MRI

PurposeT1 mapping is an emerging MRI research tool to assess diseased myocardial tissue. Recent research has been focusing on the image acquisition protocol and motion correction, yet little attention has been paid to the curve fitting algorithm. MethodsAfter nonrigid registration of the image series, a vectorized Levenberg-Marquardt (LM) technique is proposed to improve the robustness of the curve fitting algorithm by allowing spatial regularization of the parametric maps. In addition, a region-based initialization is proposed to improve the initial guess of the T1 value. The algorithm was validated with cardiac T1 mapping data from 16 volunteers acquired with saturation-recovery (SR) and inversion-recovery (IR) techniques at 3T, both pre- and post-injection of a contrast agent. Signal models of T1 relaxation with 2 and 3 parameters were tested. ResultsThe vectorized LM fitting showed good agreement with its pixel-wise version but allowed reduced calculation time (60 s against 696 s on average in Matlab with 256 × 256 × 8(11) images). Increasing the spatial regularization parameter led to noise reduction and improved precision of T1 values in SR sequences. The region-based initialization was particularly useful in IR data to reduce the variability of the blood T1. ConclusionsWe have proposed a vectorized curve fitting algorithm allowing spatial regularization, which could improve the robustness of the curve fitting, especially for myocardial T1 mapping with SR sequences.

Assessment of liver function using T1 mapping on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid enhanced MRI

Objective To investigate the effectiveness of T1 mapping on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA-enhanced) MRI for the assessment of liver function. Methods One hundred and twenty six patients with clinically suspected focal liver lesions and chronic viral hepatitis B underwent MRI were prospectively enrolled. Patients were divided into four subgroups as follows: chronic viral hepatitis B (n=22), liver cirrhosis with Child-Pugh A (n=52), Child-Pugh B (n=41), Child-Pugh C (n=11). Twenty three healthy volunteers with normal liver function were enrolled as control group. Non-enhanced and Gd-EOB-DTPA enhanced MRI of liver were performed in all subjects. Look-Locker sequences with exactly the same scan parameters and geometry position (the level of porta hepatis) were performed pre and post-contrast separately at 5, 10, 15 and 20 minutes after Gd-EOB-DTPA administration. T1 relaxation times and reduction rates of T1 relaxation times [ΔT1(%)] of the liver parenchyma were measured and calculated. One-way ANOVA was used to compare T1 relaxation times and ΔT1(%) for control group, chronic viral hepatitis B group, liver cirrhosis with Child-Pugh A group, Child-Pugh B group, and Child-Pugh C group. ROC curve analysis was performed to compare the diagnostic performance of T1 relaxation times and ΔT1(%) values in discriminating control group+ chronic viral hepatitis B group+ liver cirrhosis with Child-Pugh A group from Child-Pugh B+ C group. Results T1 relaxation times and ΔT1(%) showed significant difference (P<0.05) among control group and different liver function groups. T1 relaxation times and ΔT1(%) of both liver cirrhosis with Child-Pugh B group and Child-Pugh C group were significantly different (P<0.05) in comparison with those of control group, chronic viral hepatitis B group and liver cirrhosis with Child-Pugh A group at all time points. T1 relaxation times of the control group, chronic viral hepatitis B group, liver cirrhosis with Child-Pugh A group and Child-Pugh B group reduced with the scanning time increase, ΔT1(%) raised with the scanning time increase. T1 relaxation times progressively increased from control group to Child-Pugh C group at every time point. ΔT1(%) showed a constant decrease from control group to Child-Pugh C group at all time points. The areas under ROC curve of T1 relaxation time pre and post-contrast at 5, 10, 15 and 20 minutes for assessment of liver function were 0.817, 0.952, 0.950, 0.946, and 0.949 respectively. The areas under ROC curve of ΔT1(%) post-contrast at 5, 10, 15 and 20 minutes for evaluation of liver function were 0.873, 0.876, 0.885, and 0.898, respectively. Conclusion Gd-EOB-DTPA-enhanced T1 mapping MRI is useful for the evaluation of liver function, and helpful for distinguishing patients with moderate and severe liver damage from normal and mild liver damage. Key words: Contrast media; Magnetic resonance imaging; Liver function

Quantitative T2 Mapping of Knee Cartilage: Comparison between the Synthetic MR Imaging and the CPMG Sequence.

The purpose was to evaluate the feasibility of quantitative MRI T2 mapping based on the quantitative MRI (QRAPMASTER) sequence for the quantitative assessment of knee cartilage. The T2 values from the phantom study showed excellent correlation between the two techniques (r2 = 0.998). The cartilage T2 values exhibited strong correlations (r2 = 0.867–0.982). Quantitative MRI (qMRI) T2 mapping can be used as an alternative to multi-echo T2 mapping, with relatively short scan time.

Imaging of root zone processes using MRI T1 mapping

Noninvasive imaging in the root soil compartment is mandatory for improving knowledge about root soil interactions and uptake processes which eventually control crop growth and productivity. Here we propose a method of MRI T1 relaxation mapping to investigate water uptake patterns, and as second example, in combination with neutron tomography (NT), property changes in the rhizosphere.The first part demonstrates quantification of solute enrichment by advective transport to the roots due to water uptake. This accumulation is counterbalanced by net downward flow and dispersive spreading. One can furthermore discriminate between zones of high accumulation patterns and zones with much less enrichment. This behavior persists over days. The second part presents the novel combination of MRI with neutron tomography to couple static, proton density information of roots and their interface to the surrounding soil with information about the local water dynamics, reflected by NMR relaxation times. The root soil interface of a broad bean plant is characterized by slightly increasing MRI and NT signal intensity but decreasing T1 relaxation time indicating locally changed soil properties.

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

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

The effect of autologous adipose derived mesenchymal stem cell therapy in the treatment of a large osteochondral defect of the knee following unsuccessful surgical intervention of osteochondritis dissecans \u2013 a case study

BackgroundA prospective analysis of the effect of autologous adipose derived mesenchymal stem cell (MSC) therapy in the treatment of an osteochondral defect of the knee with early progressive osteoarthritis following unsuccessful surgical intervention of osteochondritis dissecans (OCD).Case presentationAfter failed conventional management of OCD a patient undergoes intra-articular MSC therapy. Patient outcome measures included the Numeric Pain Rating Scale (NPRS), the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Structural outcome was assessed using MRI with the novel technique of T2 mapping used to indicate cartilage quality. Following MSC therapy the patient reported improvement in pain and function as measured by NPRS, WOMAC and KOOS. Repeat MRI analysis showed regeneration of cartilage. MRI T2 mapping indicated hyaline like cartilage regrowth.ConclusionIn this report, the use of MSCs, after unsuccessful conventional OCD management, resulted in structural, functional and pain improvement. These results highlight the need to further study the regenerative potential of MSC therapy.Trial registrationAustralian and New Zealand Clinical Trial Registry Number - ACTRN12615000258550 (Date registered 19/03/2015 – retrospectively registered).

Comparison of 10- and 20-min hepatobiliary phase images on Gd-EOB-DTPA-enhanced MRI T1 mapping for liver function assessment in clinic

To compare hepatobiliary phase (HBP) images obtained 10 and 20min after Gd-EOB-DTPA-enhanced MRI for liver function assessment in clinic on 3.0 T MR imaging. 103 patients were separated into four groups: 38 patients for the normal liver function (NLF) group, 33 patients for the liver cirrhosis with Child-Pugh A (LCA) group, 21 patients for the liver cirrhosis with Child-Pugh B group, and 11 patients for a liver cirrhosis with Child-Pugh C group. T1 relaxation times (T1rt) were measured on T1 mapping and reduction rates of T1rt (rrT1rt) were calculated. HBP images were obtained at the 10- and 20-min mark after Gd-EOB-DTPA enhancement. T1rt on pre-enhancement imaging showed no significant difference (p>0.05) among all four groups. T1rt for both the 10-min HBP and the 20-min HBP showed a significant difference (p<0.05) among all groups, but showed no significant difference (p>0.05) between the NLF group and the LCA group. T1rt and rrT1rt showed no significant difference (p>0.05) between 10-min HBP and 20-min HBP among all groups. The ROC analysis on 10-min HBP and 20-min HBP showed a lower diagnostic performance between NLF group and LCA group (AUC from 0.532 to 0.582), but high diagnostic performance (AUC from 0.788 to 1.000) among others group. In comparing 10-min HBP and 20-min HBP T1 mapping after Gd-EOB-DTPA enhancement, our results suggest that 10-min HBP T1 mapping is a feasible option for quantitatively assessing liver function.

The Degeneration of Medial Meniscus Detected by T2 Mapping MRI According to the Severity of Medial Knee Osteoarthritis

The Degeneration of Medial Meniscus Detected by T2 Mapping MRI According to the Severity of Medial Knee Osteoarthritis

Evaluating segmental liver function using T1 mapping on Gd-EOB-DTPA-enhanced MRI with a 3.0 Tesla

BackgroundAssessing the liver function provides valuable information to evaluate surgical risk and plan accordingly. Current studies focus on whole liver function evaluation. However, assessment of segmental liver function is equally important in the clinical practice. The purpose of this study was to investigate whether Gd-EOB-DTPA-enhanced MRI can evaluate the liver function of each segment by using T1 mapping at 3 Tesla MRI.MethodsOne hundred three patients were classified into one of 4 groups: a normal liver function (NLF) group (n = 38), a liver cirrhosis with Child-Pugh A (LCA) group (n = 33), a liver cirrhosis with Child-Pugh B (LCB) group (n = 21), and a liver cirrhosis with Child-Pugh C (LCC) group (n = 11). All patients underwent Gd-EOB-DTPA-enhanced MRI scans. T1 relaxation times were measured on the liver superimposing T1 mapping images. Reduction rate (△%) of T1 relaxation time of the liver parenchyma were calculated.ResultsAfter 20 min of Gd-EOB-DTPA enhancement, the T1 relaxation time of all liver segments in the LCC group were different from those in all the other groups, and more liver segments from the LCB and LCA groups different from the NLF group (p < 0.05). For the LCB group, the areas under the receiver operating characteristic curves (AUCs) of different liver segments for hepatobiliary phase (HBP) were 0.654-0.904 on T1 relaxation time, and 0.709-0.905 on △%. For the LCC group, the AUCs of different liver segments for HBP were 0.842–0.997 on T1 relaxation time, and 0.887–0.990 on △%.ConclusionsFor LCB patients, segmental liver function evaluation is possible using Gd-EOB-DTPA-enhanced MRI T1 mapping. For LCC patients, all liver segments can be used to evaluate liver function and both T1 relaxation time and the △% of T1 relaxation time have good diagnostic performance.