Quantitative Magnetic Resonance Imaging Assessment Research Articles

Pediatric Sickle Cell Disease and Stroke: A Literature Review.

Both ischemic and hemorrhagic strokes in children can be a complication of sickle cell disease, which also affects adults. The occurrence is high without any screening or preventative care.This review article found that although transcranial Doppler (TCD) has reduced the prevalence of stroke in pediatric patients, there is still a need for an epidemiological survey to define such screening for adults, the ideal dose of hydroxyurea to reduce the incidence of stroke, and to identify silent cerebral stroke to prevent its complications. Increased hydroxyurea prescription and specific antibiotic and vaccination regimes lowered the occurrence of this condition. In pediatric cases with a time-averaged mean of the maximal velocity greater than 200cm/s, transcranial Doppler screeningand preventive chronic transfusion for at least the first year have lowered the occurrence of stroke by up to 10 times. The ideal dose of hydroxyurea is still debatable, but it seems to reduce the risk of the first stroke to a comparable level in the average population. Adult ischemic and hemorrhagic stroke prevention has not yet received the same attention. Though there are fewer studies, sickle cell disease is also more common than age-matched controls in terms of silent cerebral infarctionon magnetic resonance imaging (MRI),as well as other neurological problems such as cognitive impairment, seizures, and headaches. Currently, there is no evidence-supported way to prevent ischemic stroke in adults at any age. Also, there is no defined ideal dose of hydroxyurea that can be helpful in preventing strokes. Data also lack a way to identify a silent cerebral infarction, so its complications can be prevented. An additional epidemiological survey may help in the prevention of the condition. The primary aim of this article was to emphasize the importance of information on clinical, neuropsychological, and quantitative MRI assessment of sickle cell patients to understand the epidemiology and etiology of stroke in sickle cell patients to prevent stroke and its related morbidity.

Quantitative magnetic resonance imaging assessment of muscle composition in myotonic dystrophy mice

Myotonic dystrophy type 1 (DM1) is a severe autosomal dominant neuromuscular disease in which the musculoskeletal system contributes substantially to overall mortality and morbidity. DM1 stems from a noncoding CTG trinucleotide repeat expansion in the DMPK gene. The human skeletal actin long repeat (HSALR) mouse model reproduces several aspects of the disease, but the muscle-wasting phenotype of this model has never been characterized in vivo. Herein, we used quantitative MRI to measure the fat and muscle volumes in the leg compartment (LC) of mice. These acquired data were processed to extract relevant parameters such as fat fraction and fat infiltration (fat LC/LC) in HSALR and control (FBV) muscles. These results showed increased fat volume (fat LC) and fat infiltration within the muscle tissue of the leg compartment (muscle LC), in agreement with necropsies, in which fatty clumps were observed, and consistent with previous findings in DM1 patients. Model mice did not reproduce the characteristic impaired fat fraction, widespread fat replacement through the muscles, or reduced muscle volume reported in patients. Taken together, the observed abnormal replacement of skeletal muscle by fat in the HSALR mice indicates that these mice partially reproduced the muscle phenotype observed in humans.

Feasibility of simultaneous high-resolution anatomical and quantitative magnetic resonance imaging of sciatic nerves in patients with Charcot-Marie-Tooth type 1A (CMT1A) at 7T.

Magnetic resonance imaging (MRI) of peripheral nerves can provide image-based anatomical information and quantitative measurement. The aim of this pilot study was to investigate the feasibility of high-resolution anatomical and quantitative MRI assessment of sciatic nerve fascicles in patients with Charcot-Marie-Tooth (CMT) 1A using 7T field strength. Six patients with CMT1A underwent imaging on a high-gradient 7T MRI scanner using a 28-channel knee coil. Two high-resolution axial images were simultaneously acquired using a quantitative double-echo in steady-state (DESS) sequence. By comparing the two DESS echoes, T2 and apparent diffusion coefficient (ADC) maps were calculated. The cross-sectional areas and mean T2 and ADC were measured in individual fascicles of the tibial and fibular (peroneal) portions of the sciatic nerve at its bifurcation and 10 mm distally. Disease severity was measured using Charcot-Marie-Tooth Examination Score (CMTES) version 2 and compared to imaging findings. We demonstrated the feasibility of 7T MRI of the proximal sciatic nerve in patients with CMT1A. Using the higher field, it was possible to measure individual bundles in the tibial and fibular divisions of the sciatic nerve. There was no apparent correlation between diffusion measures and disease severity in this small cohort. This pilot study indicated that high-resolution MRI that allows for combined anatomical and quantitative imaging in one scan is feasible at 7T field strengths and can be used to investigate the microstructure of individual nerve fascicles.

Differential regional perfusion of the human anterior cruciate ligament: quantitative magnetic resonance imaging assessment

PurposeSurgical reconstruction is the current standard for ACL rupture treatment in active individuals. Recently, there is renewed interest in primary repair of proximal ACL tears. Despite this, ACL biology and healing potential are currently not well understood. Vascularity is paramount in ACL healing; however, previous ACL vascularity studies have been limited to qualitative histological and dissection-based techniques. The study objective was to use contrast-enhanced quantitative-MRI to compare relative perfusion of proximal, middle, and distal thirds of the in situ ACL. We hypothesized perfusion would be greatest in the proximal third.MethodsFourteen cadaveric knees were studied (8 females, 6 males), age 25–61 years. Superficial femoral, anterior tibial, and posterior tibial arteries were cannulated; without intraarticular dissection. Contrast-enhanced quantitative-MRI was performed using a previously established protocol. ACL regions corresponding to proximal, middle, and distal thirds were identified on sagittal-oblique pre-contrast images. Signal enhancement (normalized to tibial plateau cartilage) was quantified to represent regional perfusion as a percentage of total ACL perfusion. Comparative statistics were computed using repeated measures ANOVA, and pairwise comparisons performed using the Bonferroni method.ResultsRelative perfusion to proximal, middle, and distal ACL zones were 56.0% ±17.4%, 28.2% ±14.6%, and 15.8% ±16.3%, respectively (p = 0.002). Relative perfusion to the proximal third was significantly greater than middle (p = 0.007) and distal (p = 0.001). No statistically relevant difference in relative perfusion was found to middle and distal thirds (p = 0.281). Post-hoc subgroup analysis demonstrated greater proximal perfusion in males (66.9% ± 17.3%) than females (47.8% ± 13.0%), p = 0.036.ConclusionUsing quantitative-MRI, in situ adult ACL demonstrated greatest relative perfusion to the proximal third, nearly 2 times greater than the middle third and 3 times greater than the distal third. Knowledge of differential ACL vascular supply is important for understanding pathogenesis of ACL injury and the process of biological healing following various forms of surgical treatment.

Quantitative magnetic resonance imaging assessment of the infraspinatus and teres minor in massive rotator cuff tear and its significance in clinical outcome after rotator cuff repair.

Teres minor (TM) muscle hypertrophy in large to massive rotator cuff tears (RCTs) has been considered a compensatory change to atrophy of the infraspinatus (ISP). However, few reports have assessed its relation to the prognosis after rotator cuff repair. A total of 139 patients who underwent arthroscopic repair of large to massive RCTs involving the ISP between January 2013 and December 2015 were retrospectively investigated. Occupational ratios of the ISP (OR_ISP) and TM (OR_TM) were measured by sagittal magnetic resonance imaging (MRI). Rotator cuff healing was evaluated by MRI 1 year postoperatively, and functional outcomes using the Simple Shoulder Test (SST) and Constant score and external rotator (ER) strength by isokinetic muscle performance test (IMPT) were measured. A total of 116 patients completed the MRI and IMPT at 1 year postoperatively, and functional scores were measured at least 2 years postoperatively. Of these, the repaired tendon had not healed in 34 patients (29%). There was a highly negative correlation between OR_ISP and OR_TM both pre- and postoperatively (Pearson correlation = -0.52 and -0.54, respectively). Preoperative OR_ISP was significantly higher in the healed than in the healing failure group (0.47 ± 0.10 vs. 0.41 ± 0.12, P = .02); however, postoperative OR_ISP and pre- and postoperative OR_TM were not. The preoperative OR_ISP cutoff value for healing was 0.46. For functional outcomes, only postoperative OR_ISP showed a statistical correlation with SST, Constant score (P = .04 and .03, respectively), and ER strength (P = .02). TM muscle hypertrophy in large to massive RCT appears to be a compensatory change in the progression of atrophy of the ISP muscle and was not a significant indicator of either better healing of the repaired rotator cuff tendon or better function. Only preoperative OR_ISP was an independent prognostic factor affecting rotator cuff healing after repair of large to massive RCTs.

Quantitative MRI and Clinical Assessment of Muscle Function in Adults With Cerebral Palsy.

Aim: To relate quantitative magnetic resonance imaging (MRI) of ankle plantar flexor muscles to clinical functional tests in adults with cerebral palsy (CP) and neurologically intact (NI) adults.Methods: Eleven adults with CP (aged 41 ± 12, GMFCS level I-II) and 11 NI adults (aged 35 ± 10) participated in this case-control study. We used MRI to assess muscle volume and composition of the triceps surae muscles. We quantified muscle function as maximal voluntary plantarflexion (MVC) torque and countermovement jump (CMJ) height.Results: Compared to NI adults, the MRI intramuscular fat fraction estimate was significantly higher and MRI muscle volume and functional abilities (MVC and CMJ) significantly lower in adults with CP. In NI adults, but not adults with CP, MRI muscle volume correlated significantly with MVC and CMJ. In adults with CP, the estimate of intramuscular fat levels correlated significantly with jump height in a CMJ.Discussion: This study shows reduced muscle volume and altered muscle composition in adults with CP. Muscle composition appears to provide a better marker than muscle volume of reduced muscle function and impaired performance in this population. Measurements of muscle composition could be used in the assessment of neuromuscular impairments and in the determination of rehabilitation protocols in individuals with neurological disorders.

Quantitative MDCT and MRI assessment of hepatic steatosis in genotype 4 chronic hepatitis C patients with fibrosis

BackgroundHepatic steatosis has been shown to worsen the course of liver disease in chronic hepatitis C (CHC) patients, and it may reduce the efficacy of antiviral therapy and accelerate disease progression. In this cross-sectional study, we aimed to evaluate the role of multidetector computed tomography and magnetic resonance imaging (MRI) in the quantitative assessment and grading of hepatic steatosis to evaluate the association between hepatic steatosis and fibrosis in Egyptian genotype 4-CHC (G4-CHC) patients.ResultsHistopathological hepatic steatosis was found in 70.3% of 155 patients. No correlation was found between the CT ratio and pathological hepatic steatosis. Proton density fat fraction, T1-fat fraction, and fat percentage correlated with histological steatosis grading (r = 0.953, p < 0.001; r = 0.380, p = 0.027 and r = 0.384, p = 0.025, respectively). An agreement between steatosis grading by histology and 1H-MRS was found in 74.2% of patients. Compared to other MRI modalities, proton density fat fraction had the highest area under the receiver operating characteristic curve (AUC), with 0.910, 0.931, and 0.975 for mild, moderate, and severe steatosis, respectively. The cutoff with the best ability to predict steatosis was > 4.95 for a proton density fat fraction (AUC = 0.958) with 95.8% sensitivity, 90% specificity, 78.5% positive predictive value, and 96.1% negative predictive value.Conclusion1H-MRS had good diagnostic performance in predicting hepatic steatosis in G4-CHC patients, and hence, it may offer a useful noninvasive quantitative modality for grading steatosis with clinical applicability, especially in those where a liver biopsy cannot be done.

Quantitative Magnetic Resonance Imaging Assessment of the Relationships Between Fat Fraction and R2* Inside Carotid Plaques, and Circulating Lipoproteins.

Lipid-rich necrotic core (LRNC) and intraplaque hemorrhage (IPH) are morphological features of high-risk atherosclerotic plaques. However, their relationship to circulating lipoproteins is unclear. To study associations between changes in lipoproteins vs. changes in LRNC (represented by fat fraction [FF]) and IPH (represented by R2*). Prospective. Fifty-two patients with carotid plaques, 33 males (63.5%), mean age 72 (±5). Four-point fast gradient Dixon magnetic resonance imaging (MRI) was used to quantify FF and R2* (to measure IPH) inside plaques and in vessel wall. Turbo-spin echo was used for T1 weighted sequences to guide manual segmentation. Carotid MRI and serum lipid levels were assessed at baseline and at 1-year follow-up. For patients, lipid-lowering therapy was customized to reduce low-density lipoprotein (LDL) levels below 1.8 mmol/L. Segmentation was performed with one set of regions of interest for the plaque and one for the vessel wall at the location of the plaque. Thereby MRI data for FF, R2*, and volumes in plaque- and vessel-wall segmentations could be obtained from baseline and follow-up, as well as changes over the study year. Pearson correlation coefficient for correlations. Paired samples t-test for changes over time. Significance at P < 0.05, 95% confidence interval. LDL decreased significantly (2.19-1.88 mmol/L, Z - 2.9), without correlation to changes in plaque composition, nor to the significant reduction in vessel-wall volume (-106.3 mm3 ). Plaque composition remained unchanged, FF +8.5% (P=0.366) and R2* +3.5% (P=0.304). Compared to plaque segmentations, R2* was significantly lower in the vessel-wall segmentations both at baseline (-9.3%) and at follow-up (-9.1%). The absence of correlations between changes in lipoproteins and changes in plaque composition indicates more complex relationships between these parameters than previously anticipated. The significant differences in both R2* and volume dynamics comparing plaque segmentations and vessel-wall segmentations suggest differences in their pathobiology of atherosclerosis. 1 TECHNICAL EFFICACY: Stage 4.

Quantitative magnetic resonance imaging assessment of brain injury after successful cardiopulmonary resuscitation in a rat model of asphyxia cardiac arrest.

The aim of this study was to use dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted magnetic resonance imaging (DWI) to measure changes in blood-brain barrier (BBB) permeability and cerebral edema over time in a rat model of asphyxial cardiac arrest (ACA). ACA was established by endotracheal tube clamping. Male rats were randomized into a sham group (n = 5) and three ACA groups (n = 18). After return of spontaneous circulation (ROSC), the rats were randomized to perform DWI and DCE-MRI exam in the 6h, 24h and 72h timepoint (ROSC + 6h, ROSC + 24h, and ROSC + 72h). Results shows that fifteen of 18 animals achieved successful resuscitation in the ACA groups. The average apparent diffusion coefficient(ADC) value of the whole brain in ROSC + 6h was markedly lower than those of the sham, ROSC + 24h, and ROSC + 72h. The aquaporin-4(AQP4) score in ROSC + 6h was significantly higher than those in the other groups, which were negatively correlated with the ADC values. The ratio of whole brain to masseter muscle of volume transfer constant (rKtrans), tissue interstitium-to-plasma rate constant(rKep), and fractional extra-cellular space volume(rVe) in ROSC + 6h were all significantly higher than those in the sham, ROSC + 24h, and ROSC + 72h. The transforming growth factor β1(TGF-β1) and vascular endothelial growth factor A(VEGF-a) scores in ROSC + 6h were significantly higher than those in the other groups, which were all positively correlated with rKtrans and rKep. In conclusions, brain injury is a frequent complication after CA and resuscitation. DWI and DCE-MRI can quantitatively evaluate brain injury in term of cerebral edema and BBB permeability after successful CPR.

Dynamic Quantitative Magnetic Resonance Imaging Assessment of Areas of the Lung During Free-Breathing of Patients with Chronic Obstructive Pulmonary Disease

Changes in the geometry of the chest wall due to lung hyperinflation occur in COPD. However, the quantitative assessment of impaired lung motions and its association with the clinical characteristics of COPD patients are unclear. This study aimed to investigate the respiratory kinetics of COPD patients by dynamic MRI. This study enrolled 22 COPD patients and 10 normal participants who underwent dynamic MRI and pulmonary function testing (PFT). Changes in the areas of the lung and mediastinum during respiration were compared between the COPD patients and the normal controls. Relationships between MRI, CT parameters, and clinical measures that included PFT results also were evaluated. Asynchronous movements and decreased diaphragmatic motion were found in COPD patients. COPD patients had a larger ratio of MRI-measured lung areas at expiration to inspiration, a smaller magnitude of the peak area change ratio, and a smaller mediastinal-thoracic area ratio than the normal participants. The lung area ratio was associated with FEV1/FVC, predicted RV%, and CT lung volume/predicted total lung capacity (pTLC). The lung area ratio of the right lower and left lower lungs was significantly correlated with emphysema of each lower lobe. The expiratory mediastinal-thoracic area ratio was associated with FEV1% predicted and RV/TLC. Changes in the lung areas of COPD patients as shown on MRI reflected the severity of airflow limitation, hyperinflation, and the extent of emphysema. Dynamic MRI provides essential information about respiratory kinetics in COPD.

Qualitative And Quantitative Magnetic Resonance Imaging Assessment Of Focal Liver Lesions: A Study To Evaluate The Role Of Different MRI Sequences.

Background: Focal liver lesions have a broad differential diagnosis. MRI with its improved soft tissue characterization and newer sequences can significantly narrow the differentials especially when discriminating benign from malignant lesions. Methods: T1, T1 IN AND OUT OF PHASE, T2, LONG TE T2 AND Diffusion Weighted Imaging was done in 159 patients with USG documented focal liver lesion. Qualitative and quantitative assessment of ADC values and long TE images was done and a threshold for differentiating benign from malignant lesions was obtained. The MRI diagnosis was compared with final diagnosis obtained from histopathology in most cases or follow up and other tests (markers and RBC scan) were histopathology was not available. Sensitivity, specificity and accuracy of MRI sequences in differentiating various focal lesions were obtained. Results: T1 weighted images were useful for identifying fat, hemorrhage and iron within the lesions. T2 weighted imaging was able to correctly classify 82.0% lesions as malignant and 83.7% lesions as benign. Long TE T2 images were highly accurate in distinguishing haemangiomas and cysts from solid lesions. On diffusion-weighted (DW) imaging, 89.5% (i.e. 60 out of 67) lesions were correctly classified as malignant and 88.0% (i.e. 81 out of 92) lesions were correctly classified as benign. Threshold ADC value of 1.37 × 10-3 mm2/s is highly accurate for differentiating malignant from benign lesions. Conclusion: DWI is a sine qua non in liver lesion assessment allowing improved detection and characterization. Long TE T2 weighted imaging can accurately detect haemangiomas and cysts and rule out metastasis.

Quantitative MRI Assessment of Pancreatic Steatosis Using Proton Density Fat Fraction in Pediatric Obesity.

ObjectiveTo assess the feasibility of quantitatively assessing pancreatic steatosis using magnetic resonance imaging (MRI) and its correlation with obesity and metabolic risk factors in pediatric patients.Materials and MethodsPediatric patients (≤ 18 years) who underwent liver fat quantification MRI between January 2016 and June 2019 were retrospectively included and divided into the obesity and control groups. Pancreatic proton density fat fraction (P-PDFF) was measured as the average value for three circular regions of interest (ROIs) drawn in the pancreatic head, body, and tail. Age, weight, laboratory results, and mean liver MRI values including liver PDFF (L-PDFF), stiffness on MR elastography, and T2* values were assessed for their correlation with P-PDFF using linear regression analysis. The associations between P-PDFF and metabolic risk factors, including obesity, hypertension, diabetes mellitus (DM), and dyslipidemia, were assessed using logistic regression analysis.ResultsA total of 172 patients (male:female = 125:47; mean ± standard deviation [SD], 13.2 ± 3.1 years) were included. The mean P-PDFF was significantly higher in the obesity group than in the control group (mean ± SD, 4.2 ± 2.5% vs. 3.4 ± 2.4%; p = 0.037). L-PDFF and liver stiffness values showed no significant correlation with P-PDFF (p = 0.235 and p = 0.567, respectively). P-PDFF was significantly associated with obesity (odds ratio 1.146, 95% confidence interval 1.006–1.307, p = 0.041), but there was no significant association with hypertension, DM, and dyslipidemia.ConclusionMRI can be used to quantitatively measure pancreatic steatosis in children. P-PDFF is significantly associated with obesity in pediatric patients.

The Clinical and MRI Effect of TNF-α &amp;nbsp;Inhibitor in Spondyloarthritis Patients with Hip Involvement：A Real-World Prospective Clinical Study

Background: Hip involvement is an important cause of disability and poor prognostic in patients with spondyloarthritis (SpA). TNF-α inhibitor treatment had been demonstrated to be effective in SpA patients with hip arthritis, however, quantitative assessment with magnetic resonance imaging (MRI) in the long-term follow-up still needs further application. This study was performed to quantitatively assess the detailed clinical remission and MRI changes of hip involvement under the treatment of TNF-α inhibitor versus control in SpA patients. Methods: A total of 239 SpA patients with hip arthritis were involved in this study and MTX and SSZ were given as basic treatment. 165 of them received TNF-α inhibitor plus basic treatment and 74 patients in the control group received basic treatment only. The clinical symptoms were assessed at baseline, week 12, week 24, and week 52. The MRI performances of hip arthritis including bone marrow edema (BME) and synovitis were quantitatively assessed at baseline and week 52 using Hip MRI Inflammation Scoring System (HIMRISS). Findings: The clinical symptoms of ESR, CRP, BASDAI, Harris, and ASDAS-ESR of both groups got significant clinical remission at week 52 (p<0.001). However, the disease activity change levels at week 52 in control group were significantly worse than TNF group. In week 52, MRI performance showed significant remission trend in TNF-α inhibitor group versus baseline of which total HIMRISS scores decreased significantly ( 26.49±10.37 vs 20.59±9.41, p<0.001), but the control group only had slight improvement trend (p<0.05). Interpretation: TNF-α inhibitor could significantly improve the clinical and MRI manifestation of hip involvement in SpA patients, and the treatment effect was better than controls. Quantitative MRI assessment combined with clinical assessment could accurately and comprehensively evaluate the treatment effect of TNF for SpA patients with hip involvement , and it will help to guide accurate and targeted treatment. Funding: This work was supported by the National Basic Research Program of China (No. 2015CB553704) and National Natural Science Foundation of China(No.81871273). Declaration of Interest: We declare that all authors do not have a financial conflict of interest. Ethical Approval: The study was approved by the ethics committee of Xijing Hospital of China (instruction number: 20110303-7).

Quantitative Magnetic Resonance Imaging Assessment of the Quadriceps Changes during an Extreme Mountain Ultramarathon.

Extreme ultra-endurance races are growing in popularity, but their effects on skeletal muscles remain mostly unexplored. This longitudinal study explores physiological changes in mountain ultramarathon athletes' quadriceps using quantitative magnetic resonance imaging (MRI) coupled with serological biomarkers. The study aimed to monitor the longitudinal effect of the race and recovery and to identify local inflammatory and metabolic muscle responses by codetection of biological markers. An automatic image processing framework was designed to extract imaging-based biomarkers from quantitative MRI acquisitions of the upper legs of 20 finishers at three time points. The longitudinal effect of the race was demonstrated by analyzing the image markers with dedicated biostatistical analysis. Our framework allows for a reliable calculation of statistical data not only inside the whole quadriceps volume but also within each individual muscle head. Local changes in MRI parameters extracted from quantitative maps were described and found to be significantly correlated with principal serological biomarkers of interest. A decrease in the PDFF after the race and a stable paramagnetic susceptibility value were found. Pairwise post hoc tests suggested that the recovery process differs among the muscle heads. This longitudinal study conducted during a prolonged and extreme mechanical stress showed that quantitative MRI-based markers of inflammation and metabolic response can detect local changes related to the prolonged exercise, with differentiated involvement of each head of the quadriceps muscle as expected in such eccentric load. Consistent and efficient extraction of the local biomarkers enables to highlight the interplay/interactions between blood and MRI biomarkers. This work indeed proposes an automatized analytic framework to tackle the time-consuming and mentally exhausting segmentation task of muscle heads in large multi-time-point cohorts.

Very early MRI responses to therapy as a predictor of later radiographic progression in early rheumatoid arthritis

BackgroundThe objective of this study was to evaluate early changes in magnetic resonance imaging (MRI) and clinical disease activity measures as predictors of later structural progression in early rheumatoid arthritis (RA).MethodsThis was a post hoc analysis of data pooled across treatments from a three-arm (tofacitinib monotherapy, tofacitinib with methotrexate [MTX], or MTX monotherapy) trial of MTX-naïve patients with early, active RA. Synovitis, osteitis and erosions were assessed with the Outcome Measures in Rheumatology (OMERACT) RA MRI scoring system (RAMRIS) and RAMRIQ (automated quantitative RA MRI assessment system; automated RAMRIS) at months 0, 1, 3, 6 and 12. Radiographs were assessed at months 0, 6 and 12, and clinical endpoints were assessed at all timepoints. Univariate and multivariate analyses explored the predictive value of early changes in RAMRIS/RAMRIQ parameters and disease activity measures, with respect to subsequent radiographic progression.ResultsData from 109 patients with a mean RA duration of 0.7 years were included. In univariate analyses, changes in RAMRIS erosions at months 1 and 3 significantly predicted radiographic progression at month 12 (both p < 0.01); changes in RAMRIQ synovitis and osteitis at months 1 and 3 were significant predictors of RAMRIS erosions and radiographic progression at month 12 (all p < 0.01). In subsequent multivariate analyses, RAMRIS erosion change at month 1 (p < 0.05) and RAMRIQ osteitis changes at months 1 and 3 (both p < 0.01) were significant independent predictors of radiographic progression at month 12. Univariate analyses demonstrated that changes in Clinical Disease Activity Index (CDAI) and Disease Activity Score in 28 joints, erythrocyte sedimentation rate (DAS28-4[ESR]) at months 1 and 3 were not predictive of month 12 radiographic progression.ConclusionsMRI changes seen as early as 1 month after RA treatment initiation have the potential to better predict long-term radiographic progression than changes in disease activity measures.Trial registrationClinicalTrials.gov, NCT01164579.

Vascular Burden Score Impacts Cognition Independent of Amyloid PET and MRI Measures of Alzheimer's Disease and Vascular Brain Injury.

To determine the impact of vascular burden on rates of decline in episodic memory and executive function. We hypothesize that greater vascular burden will have an additive negative impact on cognition after accounting for baseline cognitive impairment, positron emission tomography (PET) amyloid burden, and magnetic resonance imaging (MRI) measures. Individuals were followed an average of 5 years with serial cognitive assessments. Predictor variables include vascular burden score (VBS), quantitative brain MRI assessment, and amyloid imaging. Subjects consisted of 65 individuals, 53% of whom were male, aged 73.2±7.2 years on average with an average of 15.5±3.3 years of educational achievement. Baseline cognitive impairment was significantly associated poorer episodic memory (p < 0.0001), smaller hippocampal volume (p < 0.0001), smaller brain volume (p = 0.0026), and greater global Pittsburg Imaging Compound B (PiB) index (p = 0.0008). Greater amyloid burden was associated with greater decline in episodic memory over time (β= -0.20±0.07, p < 0.005). VBS was significantly associated with the level of executive function performance (β= -0.14±0.05, p < 0.005) and there was a significant negative interaction between VBS, cognitive impairment, and PiB index (β= -0.065±0.03, p = 0.03). Our results find a significant influence of VBS independent of standard MRI measures and cerebral amyloid burden on executive function. In addition, VBS reduced the amount of cerebral amyloid burden needed to result in cognitive impairment. We conclude that the systemic effects of vascular disease as reflected by the VBS independently influence cognitive ability.

Quantitative MRI assessment of mucinous rectal adenocarcinoma to predict tumour response after neoadjuvant therapy

To evaluate the association between volume ratio of the mucus pool and tumour response to neoadjuvant therapy in patients with mucinous rectal adenocarcinoma (MC). The volume of the mucus pool and whole tumour on pre-therapeutic T2-weighted magnetic resonance imaging (MRI) of 79 patients was measured using semi-automated software. Mucus pool volume, whole tumour volume, and volume ratio of the mucus pool were compared to tumour response and tumour and lymph node downstaging after neoadjuvant therapy using receiver operating characteristic curve (ROC) and multivariate logistic regression analysis. After preoperative neoadjuvant therapy of rectal MC, the rate of pathological complete response, tumour downstaging, tumour response, and lymph node downstaging were 9%, 48%, 39% and 58%, respectively. Tumour downstaging more frequently occurred in patients with a mucus pool volume ratio of at least 68.3% (area under the ROC curve [AUC], 0.793 with 95% confidence interval [CI]: 0.693-0.893), and at least 62.1% for identifying those with a higher tumour response with an AUC of 0.739 (95% CI: 0.630-0.847). A higher volume ratio of mucus pool in patients with MC may be related to more tumour downstaging and therapy response, and therefore, could serve as an independent imaging biomarker for predicting tumour response to neoadjuvant therapy.

Quantitative magnetic resonance imaging assessment of lateral atlantoaxial joint meniscoid composition: a validation study.

Lateral atlantoaxial (LAA) joint meniscoid composition may have clinical significance in patients following neck trauma. However, the existing method of radiologically assessing meniscoid composition has an inherent element of subjectivity, which could contribute to measurement variability. The present study sought to investigate the accuracy of two-point Dixon fat/water separation MRI as a quantitative assessment of LAA joint meniscoid composition. Sixteen LAA joint meniscoids were excised from four cadavers (mean [SD] age 79.5 [3.7]years; one female) following cervical spine MRI (two-point Dixon, T1-weighted VIBE and T2-weighted SPACE sequences). Composition of LAA joint meniscoids was undertaken by (1) histological examination by light microscopy, (2) calculation of fat fraction by Dixon MRI (both in-phase/opposed-phase and fat/water methods), and (3) the existing method of considering VIBE and SPACE signal intensities. Analysis was performed using the kappa statistic with linear weighting. Microscopy revealed three, five, and eight meniscoids to be composed of adipose, fibroadipose, and fibrous tissues, respectively. Dixon sequence MRI classified 11 of these meniscoids correctly, with 'substantial' level of agreement (In-phase/Opp-phase kappa statistic = 0.78 [95% CI 0.38, 1.17]; fat/water kappa statistic = 0.72 [95% CI 0.32, 1.11]). Level of agreement between microscopy and the VIBE and SPACE method was 'slight' (kappa statistic = 0.02 [95% CI - 0.34, 0.38]). Findings suggest that Dixon fat/water separation MRI may have superior utility in the assessment of LAA joint meniscoid composition than the existing method of considering VIBE and SPACE signal intensities. These slides can be retrieved under Electronic Supplementary Material.

Quantitative magnetic resonance imaging assessments of autosomal recessive polycystic kidney disease progression and response to therapy in an animal model.

BackgroundAutosomal recessive polycystic kidney disease (ARPKD) is associated with significant mortality and morbidity, and currently, there are no disease-specific treatments available for ARPKD patients. One major limitation in establishing new therapies for ARPKD is a lack of sensitive measures of kidney disease progression. Magnetic resonance imaging (MRI) can provide multiple quantitative assessments of the disease.MethodsWe applied quantitative image analysis of high-resolution (noncontrast) T2-weighted MRI techniques to study cystic kidney disease progression and response to therapy in the PCK rat model of ARPKD.ResultsSerial imaging over a 2-month period demonstrated that renal cystic burden (RCB, %)=[total cyst volume (TCV)/total kidney volume (TKV) × 100], TCV, and, to a lesser extent, TKV detected cystic kidney disease progression, as well as the therapeutic effect of octreotide, a clinically available medication shown previously to slow both kidney and liver disease progression in this model. All three MRI measures correlated significantly with histologic measures of renal cystic area, although the correlation of RCB and TCV was stronger than that of TKV.ConclusionThese preclinical MRI results provide a basis for applying these quantitative MRI techniques in clinical studies, to stage and measure progression in human ARPKD kidney disease.

Multimodal quantitative MRI assessment of cortical damage in relapsing-remitting multiple sclerosis.

To investigate magnetization transfer ratio (MTR), T1 relaxation time, and proton density (PD) as indicators of gray matter damage in relapsing-remitting multiple sclerosis (RRMS), reflecting different aspects of microstructural damage and as imaging correlates of clinical disability. We aimed to determine which of these parameters may optimally quantify cortical damage, and serve as an imaging surrogate of clinical disability. In this study, cortical values of MTR, a surrogate for demyelination in MS, of PD, reflecting replacement of neural tissue by water, and of T1 , indicating a complex array of microstructural changes, were assessed in a group of RRMS patients in comparison to healthy controls (HC). 22 RRMS patients with varying disease duration (4.0 ± 6.54 years) and 10 HC received quantitative 3T magnetic resonance imaging (MRI) with MTR, T1 , and PD mapping. We tested for differences in cortical measurements between patients and HC. Additionally, correlation with disability as quantified by the Expanded Disability Status Scale was investigated. Cortical parameter values were significantly altered in the RRMS group, with increased values of T1 (P = 0.008) and PD (P = 0.028) and reduced values of MTR (P = 0.043). Only cortical T1 was correlated with clinical disability measurements (P = 0.001, r = 0.65). Receiver operating characteristic analysis demonstrated the best discriminatory power for T1 (area under the curve 0.79, PD: 0.75, MTR 0.73). Out of the parameters studied, cortical T1 is best suited to detect cortical damage as an imaging surrogate of clinical disability in RRMS. J. Magn. Reson. Imaging 2016;44:1600-1607.