Morphological imaging and T2 and T2* mapping of hip cartilage at 7 Tesla MRI under the influence of intravenous gadolinium

Objectives

To investigate the influence of intravenous gadolinium on cartilage T2 and T2* relaxation times and on morphological image quality at 7-T hip MRI.

Methods

Hips of 11 healthy volunteers were examined at 7 T. Multi-echo sequences for T2 and T2* mapping, 3D T1 volumetric interpolated breath-hold examination (VIBE) and double-echo steady-state (DESS) sequences were acquired before and after intravenous application of gadolinium according to a delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) protocol. Cartilage relaxation times were measured in both scans. Morphological sequences were assessed quantitatively using contrast ratios and qualitatively using a 4-point Likert scale. Student’s t-test, Pearson’s correlation (ρ) and Wilcoxon sign-rank test were used for statistical comparisons.

Results

Pre- and post-contrast T2 and T2* values were highly correlated (T2: acetabular: ρ?=?0.76, femoral: ρ?=?0.77; T2*: acetabular: ρ?=?0.80, femoral: ρ?=?0.72). Gadolinium enhanced contrasts between cartilage and joint fluid in DESS and T1 VIBE according to the qualitative (p?=?0.01) and quantitative (p?<?0.001) analysis. The delineation of acetabular and femoral cartilage and the labrum predominantly improved with gadolinium.

Conclusions

Gadolinium showed no relevant influence on T2 or T2* relaxation times and improved morphological image quality at 7 T. Therefore, morphological and quantitative sequences including dGEMRIC can be conducted in a one-stop-shop examination.

Key Points

? Hip cartilage T2 values correlate highly before and after gadolinium at 7 T ? Hip cartilage T2* values correlate highly before and after enhancement at 7 T ? Morphological hip cartilage imaging benefits from intravenous gadolinium at 7 T ? The delineation of acetabular and femoral cartilage can be improved by gadolinium ? Morphological and quantitative sequences including dGEMRIC can be combined as a one-stop-shop examination

     

Effect of intra-articular injection of intermediate-weight hyaluronic acid on hip and knee cartilage: in-vivo evaluation using T2 mapping

Objectives

We used T2 mapping to quantify the effect of intra-articular hyaluronic acid administration (IAHAA) on cartilage with correlation to clinical symptoms.

Methods

One hundred two patients with clinical and MRI diagnosis of hip or knee grade I-III chondropathy were prospectively included. All patients received a standard MRI examination of the affected hip/knee (one joint/patient) and T2-mapping multiecho sequence for cartilage evaluation. T2 values of all slices were averaged and used for analysis. One month after MR evaluation 72 patients (38 males; mean age 51±10 years) underwent IAHAA. As a control group, 30 subjects (15 males; 51 ± 9 years) were not treated. MR and WOMAC evaluation was performed at baseline and after 3, 9, and 15 months in all patients.

Results

T2 mapping in hyaluronic acid (HA) patients showed a significant increase in T2 relaxation times from baseline to the first time point after therapy in knees (40.7 ± 9.8 ms vs. 45.8 ± 8.6 ms) and hips (40.9 ± 9.7 ms; 45.9 ± 9.5 ms) (p < 0.001). At the 9- and 15-month evaluations, T2 relaxation dropped to values similar to the baseline ones (p < 0.001 vs. 3 month). The correlation between T2 increase and pain reduction after IAHAA was statistically significant (r = 0.54, p < 0.01) in patients with grade III chondropathy.

Conclusions

T2 mapping can be used to evaluate the effect over time of IAHAA in patients with hip and knee chondropathy.

Key points

? T2 relaxation times change over time after hyaluronic acid intra-articular administration? T2 relaxation times of the medial femoral condyle correlate with WOMAC variation? T2 relaxation times are different between Outerbridge I and II-III

     

Changes in the T2 value of cartilage after meniscus transplantation over 1 year

Objectives

To evaluate the changes in the mean T2 values of articular cartilage on serial follow-up images up to 1 year in patients who underwent lateral meniscus allograft transplantation (MAT).

Methods

Fifty-two patients who underwent lateral MAT surgery at our hospital were evaluated preoperatively and at 2 days, 6 weeks, 3 months, 6 months, and 1 year after MAT using 3.0-T magnetic resonance imaging (MRI) that included T2 mapping. T2 value changes according to the arthroscopic grading of chondromalacia were evaluated in the lateral and medial compartment. Lysholm scores were obtained pre- and postoperatively.

Results

The T2 values of cartilage were significantly increased 2 days after operation, and then gradually reduced to the baseline level after 1 year in both compartments. In morphologic assessment performed after 1 year, most areas (92.9 %) showed no interval change of chondromalacia grade. Lyshom knee scores increased significantly from the mean preoperative value of 62.5 (range, 23–95) to 89.7 (range, 64–100) at 1 year (p?<?0.001).

Conclusion

Mean T2 values of cartilage following MAT exhibited a return to baseline level after 1 year. T2 measurement can be a useful tool for quantitative evaluation of postoperative cartilage changes compared to conventional MRI.

Key Points

? T2 mapping provides objective data for longitudinal monitoring following surgery.? Increased cartilage T2 values post-MAT returned to baseline in one year.? Further studies are required to predict the chondroprotective effect of MAT.

     

Comparison of T2 Relaxation Values in Subtalar Cartilage between Patients with Lateral Instability of the Ankle Joint and Healthy Volunteers

Purpose

To evaluate the difference between T2 relaxation values of the subtalar cartilage in lateral ankle instability patients and healthy volunteers.

Materials and Methods

This institutional review board-approved study included 27 preoperative magnetic resonance imaging (MRI) examinations of 26 patients who underwent Broström operations. Data of previously enrolled healthy volunteers (12 volunteers, 13 MRIs) were used as controls. Two radiologists independently measured T2 values in eight posterior subtalar joint cartilage compartments: central calcaneus anterior (CCA) and posterior (CCP), central talus anterior (CTA) and posterior (CTP), lateral calcaneus anterior (LCA) and posterior (LCP), and lateral talus anterior (LTA) and posterior (LTP). Patient and control values were compared using linear regression analysis. Inter- and intraobserver agreement was calculated.

Results

Mean T2 values were significantly higher in the patient group in all measurements of subtalar joint cartilage compartments (p < 0.05) except that in LTP (p = 0.085) measured by reviewer 1. Both inter- and intraobserver agreements were excellent.

Conclusions

The T2 relaxation values of the subtalar cartilage were significantly higher in lateral ankle instability patients compared with those of controls.

Key Points

? Subtalar cartilage T2 values are increased in patients with lateral ankle instability. ? This trend was demonstrated regardless of the presence of talar dome cartilage lesions. ? Inter-and intraobserver agreements were excellent (intraclass coefficient range, 0.765-0.951) in subtalar cartilage T2 mapping.

     

Repair tissue quality after arthroscopic autologous collagen-induced chondrogenesis (ACIC) assessed via T2* mapping

Objective

A novel single-stage approach using arthroscopic microdrilling and atelocollagen/fibrin-gel application is employed for cartilage repair of the knee. The purpose of our study was to investigate the morphological and biochemical MRI outcome after this technique.

Materials and methods

A retrospective case series of ten patients (mean age 45 years) with symptomatic chondral defects in the knee who were treated arthroscopically with microdrilling and atelocollagen application was analyzed. All defects were ICRS grade III or IV and the sizes were 2–8 cm² intra-operatively. All patients underwent morphological MRI and T2-star mapping at 1.5 T at 1-year follow-up. The magnetic resonance observation of cartilage repair tissue (MOCART) score was assessed. T2* relaxation time values of repair tissue and a healthy native cartilage area was assessed by means of region of interest analysis on the T2* maps.

Results

The mean MOCART score at 1-year follow-up was 71.7?±?21.0 ranging from 25 to 95. The mean T2* relaxation times were 30.6?±?11.3 ms and 28.8?±?6.8 ms for the repair tissue and surrounding native cartilage, respectively. The T2* ratio between the repair tissue and native cartilage was 105 %?±?30 %, indicating repair tissue properties similar to native cartilage.

Conclusions

An arthroscopic single-stage procedure using microdrilling in combination with atelocollagen gel and fibrin-glue can provide satisfactory MRI results at 1-year follow-up, with good cartilage defect filling. The T2* values in the repair tissue achieved similar values compared to normal hyaline cartilage.

     

T2* mapping and delayed gadolinium-enhanced magnetic resonance imaging in cartilage (dGEMRIC) of glenohumeral cartilage in asymptomatic volunteers at 3 T

Objectives

To establish baseline T2* and T1_Gd values of glenohumeral cartilage at 3 T.

Methods

Forty asymptomatic volunteers (mean age: 24.8?±?2.2 years) without shoulder abnormalities were included. The MRI protocol comprised a double-echo steady-state (DESS) sequence for morphological cartilage evaluation, a gradient-echo multiecho sequence for T2* assessment, and a gradient-echo dual-flip-angle sequence for T1_Gd mapping. Statistical assessment involved a one-way analysis of variance (ANOVA) to identify the differences between various regions of the glenohumeral joint and intraclass correlation (ICC) analysis comparing repetitive T2* and T1_Gd measures to assess intra- and interobserver reliability.

Results

Both techniques revealed significant differences between superior and inferior glenohumeral cartilage demonstrating higher T2* (26.2 ms vs. 23.2 ms, P value?<?0.001) and T1_Gd (750.1 ms vs. 720.2 ms, P value?=?0.014) values in the superior regions. No trend was observed in the anterior-posterior measurement (P value range: 0.279–1.000). High intra- and interobserver agreement (ICC value range: 0.895–0.983) was noted for both T2* and T1_Gd mapping.

Conclusions

T2* and T1_Gd mapping are reliable in the assessment of glenohumeral cartilage. The values from this study can be used for comparison to identify cartilage degeneration in patients suffering from shoulder joint abnormalities.

Key Points

? T2* mapping and dGEMRIC are sensitive to collagen degeneration and proteoglycan depletion. ? This study aimed to establish baseline T2*/dGEMRIC values of glenohumeral cartilage. ? Both techniques revealed significant differences between superior and inferior glenohumeral cartilage. ? High intra-/interreader agreement was noted for both T2* mapping and dGEMRIC. ? These baseline normal values should be useful when identifying potential degeneration.     

Usefulness of IDEAL T2-weighted FSE and SPGR imaging in reducing metallic artifacts in the postoperative ankles with metallic hardware

Purpose

The aim of this work is to prospectively compare the effectiveness of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL), T2-weighted fast spin-echo (FSE), and spoiled gradient-echo (SPGR) MR imaging to frequency selective fat suppression (FSFS) protocols for minimizing metallic artifacts in postoperative ankles with metallic hardware.

Materials and methods

The T2-weighted and SPGR imaging with IDEAL and FSFS were performed on 21 ankles of 21 patients with metallic hardware. Two musculoskeletal radiologists independently analyzed techniques for visualization of ankle ligaments and articular cartilage, uniformity of fat saturation, and relative size of the metallic artifacts. A paired t test was used for statistical comparisons of MR images between IDEAL and FSFS groups.

Results

IDEAL T2-weighted FSE and SPGR images enabled significantly improved visualization of articular cartilage (p?<?0.05), the size of metallic artifact (p?<?0.05), and the uniformity of fat saturation (p?<?0.05). However, no significant improvement was found in the visibility of ligaments.

Conclusions

IDEAL T2-weighted FSE and SPGR imaging effectively reduces the degree of tissue-obscuring artifacts produced by fixation hardware in ankle joints and improves image quality compared to FSFS T2-weighted FSE and SPGR imaging. However, visibility of ligaments was not improved using IDEAL imaging.

     

Native myocardial T1 mapping in pulmonary hypertension: correlations with cardiac function and hemodynamics

Objectives

To analyze alterations in left ventricular (LV) myocardial T1 times in patients with pulmonary hypertension (PH) and to investigate their associations with ventricular function, mass, geometry and hemodynamics.

Methods

Fifty-eight patients with suspected PH underwent right heart catheterization (RHC) and 3T cardiac magnetic resonance imaging. Ventricular function, geometry and mass were derived from cine real-time short-axis images. Myocardial T1 maps were acquired by a prototype modified Look-Locker inversion-recovery sequence in short-axis orientations. LV global, segmental and ventricular insertion point (VIP) T1 times were evaluated manually and corrected for blood T1.

Results

Septal, lateral, global and VIP T1 times were significantly higher in PH than in non-PH subjects (septal, 1249?±?58 ms vs. 1186?±?33 ms, p?<?0.0001; lateral, 1190?±?45 ms vs. 1150?±?33 ms, p?=?0.0003; global, 1220?±?52 ms vs. 1171?±?29 ms, p?<?0.0001; VIP, 1298?±?78 ms vs. 1193?±?31 ms, p?<?0.0001). In PH, LV eccentricity index was the strongest linear predictor of VIP T1 (r?=?0.72). Septal, lateral and global T1 showed strong correlations with VIP T1 (r?=?0.81, r?=?0.59 and r?=?0.75, respectively).

Conclusions

In patients with PH, T1 times in VIPs and in the entire LV myocardium are elevated. LV eccentricity strongly correlates with VIP T1 time, which in turn is strongly associated with T1 time changes in the entire LV myocardium.

Key Points

? Native T1 mapping detects left ventricular myocardial alterations in pulmonary hypertension ? In pulmonary hypertension, native T1 times at ventricular insertion points are increased ? These T1 times correlate strongly with left ventricular eccentricity ? In pulmonary hypertension, global and segmental myocardial T1 times are increased ? Global, segmental and ventricular insertion point T1 times are strongly correlated

     

Incidentally detected enhancing lesions found in breast MRI: analysis of apparent diffusion coefficient and T2 signal intensity significantly improves specificity

Objectives

To evaluate the value of adding T2- and diffusion-weighted imaging (DWI) to the BI-RADS® classification in MRI-detected lesions.

Methods

This retrospective study included 112 consecutive patients who underwent 3.0T structural breast MRI with T2- and DWI on the basis of EUSOMA recommendations. Morphological and kinetic features, T2 signal intensity (T2 SI) and apparent diffusion coefficient (ADC) findings were assessed.

Results

Thirty-three (29.5 %) patients (mean age 57.0?±?12.7 years) had 36 primarily MRI-detected incidental lesions of which 16 (44.4 %) proved to be malignant. No single morphological or kinetic feature was associated with malignancy. Both low T2 SI (P?=?0.009) and low ADC values (≤0.87?×?10^?3 mm²s^?1, P?<?0.001) yielded high specificity (80.0 %/80.0 %). The BI-RADS classification supplemented with information from DWI and T2-WI improved the diagnostic performance of the BI-RADS classification as sensitivity remained 100 % and specificity improved from 30 % to 65.0 %. The numbers of false positive lesions declined from 39 % (N?=?14) to 19 % (N?=?7).

Conclusion

MRI-detected incidental lesions may be challenging to characterize as they have few specific malignancy indicating features. The specificity of MRI can be improved by incorporating T2 SI and ADC values into the BI-RADS assessment.

Key Points

? MRI-detected incidental lesions have few specific malignancy indicating features. ? ≥ 1 suspicious morphologic or kinetic feature may warrant biopsy. ? T2 signal intensity and DWI assessment are feasible in primarily MRI-detected lesions. ? T2 SI and DWI assessment improve the BI-RADS specificity in MRI-detected lesions.

     

Magnetic resonance imaging during management of patients with transfusion-dependent thalassemia: a single-center experience

Background

Cardiac and hepatic magnetic resonance imaging evaluation during treatment can tailor physicians’ chelation therapy titrations.

Aim

The aim of the study was to assess the relationship of cardiac and hepatic T2* values with chelation therapy in patients with transfusion-dependent thalassemia (TDT).

Methods

A total of 106 patients with TDT who were followed up in Istanbul Medical Faculty Thalassemia Center were evaluated for the study. Forty-eight (45%) patients with TDT had more than one consecutive MRI examination. The patients were divided into three subgroups according to the cardiac T2* values as the high-risk group (T2* MRI?<?10 ms), medium-risk group (T2* MRI 10-20 ms), and the low-risk group (T2* MRI?>?20 ms).

Results

The majority of patients used DFX (deferasirox) (79%) and deferiprone (DFP) (17%). Approximately 80% of patients according to cardiac T2* value and 40% of patients according to hepatic T2* value were initially in the low-risk group. Patients with follow-up MRI examinations exhibited significant improvement in liver iron concentration, which correlated with an increase in hepatic T2* values. The decrease of liver iron concentration was prominent in the DFX group (p?<?0.01). The serum ferritin level was significantly correlated with liver iron concentrations (rs?=?0.65, p?<?0.001), hepatic T2* value (rs?=?? 0.62, p?<?0.001), but not with cardiac T2* value (rs?=?? 0.20, p?=?0.07).

Conclusion

Cardiovascular and hepatic MRI is a useful follow-up tool during the assessment of risk groups and chelation therapy of patients with TDT. Consecutive MRI tests showed good monitoring of cardiac and liver iron overload.

     

Comparative reliability and diagnostic performance of conventional 3T magnetic resonance imaging and 1.5T magnetic resonance arthrography for the evaluation of internal derangement of the hip

Objective

To compare the diagnostic accuracy of conventional 3T MRI against 1.5T MR arthrography (MRA) in patients with clinical femoroacetabular impingement (FAI).

Methods

Sixty-eight consecutive patients with clinical FAI underwent both 1.5T MRA and 3T MRI. Imaging was prospectively analysed by two musculoskeletal radiologists, blinded to patient outcomes and scored for internal derangement including labral and cartilage abnormality. Interobserver variation was assessed by kappa analysis. Thirty-nine patients subsequently underwent hip arthroscopy and surgical results and radiology findings were analysed.

Results

Both readers had higher sensitivities for detecting labral tears with 3T MRI compared to 1.5T MRA (not statistically significant p=0.07). For acetabular cartilage defect both readers had higher statistically significant sensitivities using 3T MRI compared to 1.5T MRA (p=0.02). Both readers had a slightly higher sensitivity for detecting delamination with 1.5T MRA compared to 3T MRI, but these differences were not statistically significant (p=0.66). Interobserver agreement was substantial to perfect agreement for all parameters except the identification of delamination (3T MRI showed moderate agreement and 1.5T MRA substantial agreement).

Conclusion

Conventional 3T MRI may be at least equivalent to 1.5T MRA in detecting acetabular labrum and possibly superior to 1.5T MRA in detecting cartilage defects in patients with suspected FAI.

Key Points

? Conventional 3T MRI is equivalent to 1.5T MRA for diagnosing labral tears. ? Conventional 3T MRI is superior to 1.5T MRA for diagnosing acetabular cartilage defect. ? Conventional 3T MRI is equivalent to 1.5T MRA for diagnosing cartilage delamination. ? Symptom severity score was significantly higher (p<0.05) in group proceeding to surgery.

     

3T MRI of the knee with optimised isotropic 3D sequences: Accurate delineation of intra-articular pathology without prolonged acquisition times

Objectives

To investigate optimised isotropic 3D turbo spin echo (TSE) and gradient echo (GRE)-based pulse sequences for visualisation of articular cartilage lesions within the knee joint.

Methods

Optimisation of experimental imaging sequences was completed using healthy volunteers (n=16) with a 3-Tesla (3T) MRI scanner. Imaging of patients with knee cartilage abnormalities (n=57) was then performed. Acquired sequences included 3D proton density-weighted (PDW) TSE (SPACE) with and without fat-suppression (FS), and T2*W GRE (TrueFISP) sequences, with acquisition times of 6:51, 6:32 and 5:35 min, respectively.

Results

One hundred sixty-one confirmed cartilage lesions were detected and categorised (Grade II n=90, Grade III n=71). The highest sensitivity and specificity for detecting cartilage lesions were obtained with TrueFISP with values of 84.7% and 92%, respectively. Cartilage SNR mean for PDW SPACE-FS was the highest at 72.2. TrueFISP attained the highest CNR means for joint fluid/cartilage (101.5) and joint fluid/ligament (156.5), and the lowest CNR for cartilage/meniscus (48.5). Significant differences were identified across the three sequences for all anatomical structures with respect to SNR and CNR findings (p-value <0.05).

Conclusion

Isotropic TrueFISP at 3T, optimised for acquisition time, accurately detects cartilage defects, although it demonstrated the lowest contrast between cartilage and meniscus.

Key points

? Cartilage is better visualised with 3D TrueFISP than 3D SPACE sequences. ? 3D TrueFISP is a reliable sequence for detecting low- and high-grade cartilage defects. ? 3D TrueFISP at 3T provides excellent contrast between cartilage and joint fluid.

     

T1 and T2 mapping in the identification of acute myocardial injury in patients with NSTEMI

Aims

To test T1 and T2 mapping in the assessment of acute myocardial injury in patients with non-ST-segment elevation myocardial infarction (NSTEMI), evaluated before revascularization.

Methods

Forty-seven patients with acute NSTEMI underwent cardiac magnetic resonance (CMR) at 1.5 T, including T1 and T2 mapping.

Results

Coronary angiography (CA) evidenced an obstructive coronary artery disease (CAD) in 36 patients (80%) and a non-obstructive CAD in 11 patients (20%). Edema was detected in 51.1/65.9% of patients in T1/T2 maps, respectively. This difference was due to artifacts in T1 maps. T1/T2 values were significantly higher in the infarcted myocardium (IM) compared with the remote myocardium (RM) (in T1: 1151.6?±?53.5 ms vs. 958.2?±?38.6 ms, respectively; in T2: 69?±?6 ms vs. 51.9?±?2.9 ms, respectively; p?<?0.0001 for both). We found both an obstructive CAD at CA and myocardial edema at CMR in 53.2% of patients, while 8.5% of patients had a non-obstructive CAD and no edema. However, 25.5% of patients had an obstructive CAD without edema, while 12.8% of patients showed edema despite a non-obstructive CAD. Furthermore, in 6 of the edema-positive patients with multi-vessels obstructive CAD, CMR identified myocardial edema in a vascular territory different from that of the lesion supposed to be the culprit at CA.

Conclusions

In a non-negligible percentage of NSTEMI patients, T1 and T2 mapping detect myocardial edema without significant stenosis at CA and vice versa. Therefore, CA and CMR edema imaging might provide complementary information in the evaluation of NSTEMI.

     

Contrast-enhanced 3T MR Perfusion of Musculoskeletal Tumours: T1 Value Heterogeneity Assessment and Evaluation of the Influence of T1 Estimation Methods on Quantitative Parameters

Objective

To evaluate intra-tumour and striated muscle T1 value heterogeneity and the influence of different methods of T1 estimation on the variability of quantitative perfusion parameters.

Material and methods

Eighty-two patients with a histologically confirmed musculoskeletal tumour were prospectively included in this study and, with ethics committee approval, underwent contrast-enhanced MR perfusion and T1 mapping. T1 value variations in viable tumour areas and in normal-appearing striated muscle were assessed. In 20 cases, normal muscle perfusion parameters were calculated using three different methods: signal based and gadolinium concentration based on fixed and variable T1 values.

Results

Tumour and normal muscle T1 values were significantly different (p?=?0.0008). T1 value heterogeneity was higher in tumours than in normal muscle (variation of 19.8% versus 13%). The T1 estimation method had a considerable influence on the variability of perfusion parameters. Fixed T1 values yielded higher coefficients of variation than variable T1 values (mean 109.6?±?41.8% and 58.3?±?14.1% respectively). Area under the curve was the least variable parameter (36%).

Conclusion

T1 values in musculoskeletal tumours are significantly different and more heterogeneous than normal muscle. Patient-specific T1 estimation is needed for direct inter-patient comparison of perfusion parameters.

Key Points

? T1 value variation in musculoskeletal tumours is considerable. ? T1 values in muscle and tumours are significantly different. ? Patient-specific T1 estimation is needed for comparison of inter-patient perfusion parameters. ? Technical variation is higher in permeability than semiquantitative perfusion parameters.

     

Significant changes of T2 value in the peripheral zone and seminal vesicles after ejaculation

Objectives

To analyse the quantitative changes of the prostate and seminal vesicles (SV) on magnetic resonance imaging (MRI) after ejaculation.

Methods

Ten healthy young males were enrolled for T2-weighted and T2 mapping MRI before and after two consecutive ejaculations. T2 values of the peripheral zone (PZ) and the central gland (CG) at the midgland of the prostate were compared before and after ejaculation, respectively. T2 values of the PZ at the apex and base were also compared before and after, respectively. Pre- and post-ejaculation SV volumes were compared. The Wilcoxon’s signed rank test with Bonferroni adjustment was used for comparison.

Results

After ejaculation, T2 values of the PZ significantly decreased (mean, 119±20 vs. 105±21, p=0.002) while those of the CG did not significantly change at the midgland. At the apex, T2 values of the PZ also decreased significantly (mean, 114±9 vs. 94±7, p=0.002). On the other hand, T2 values of the PZ did not change at the base. SV volumes were significantly reduced after ejaculation (mean, 11.1±7.7mL vs. 7.2±6.7mL, p=0.002).

Conclusions

Ejaculation decreases T2 values of the PZ at the midgland and apex, and reduces SV volumes. Abstinence periods should be considered in evaluating the prostate and SV on MRI.

Key points

? T2 values decrease after ejaculation in the apical-mid peripheral zone. ? Ejaculation does not affect T2 values of the central gland. ? Volume of the seminal vesicles decreases after ejaculation. ? An abstinence period should be considered before pelvic MRI in men.

     

Magnetic resonance imaging and histology of ovine hip joint cartilage in two age populations: a sheep model with assumed healthy cartilage

Objective

To compare morphologically normal appearing cartilage in two age groups with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) and correlate magnetic resonance imaging (MRI) findings with histology.

Materials and methods

Twenty femoral head specimens collected from ten lambs (group I) and ten young adult sheep (group II) underwent dGEMRIC and histological assessment. A region of 2 cm² with morphologically normal-appearing cartilage was marked with a surgical suture for subsequent matching of MRI and histological sections. The MRI protocol included a three-dimensional (3D) double-echo steady-state sequence for morphological cartilage assessment, a B1 pre-scan with various flip angles for B1 field heterogeneity correction, and 3D volumetric interpolated breathhold examination for T1_Gd mapping (dGEMRIC). Histological analysis was performed according to the Mankin scoring system.

Results

A total of 303 regions of interest (ROI; 101 MRI reformats matching 101 histological sections) was assessed. Twenty-six ROIs were excluded owing to morphologically apparent cartilage damage or insufficient MR image quality. Therefore, 277 ROIs were analyzed. Histological analyses revealed distinct degenerative changes in various cartilage samples of group II (young adult sheep). Corresponding T1_Gd values were significantly lower in the group of sheep (mean T1_Gd?=?540.4 ms) compared with the group of lambs (mean T1_Gd?=?623.6 ms; p?<?0.001).

Conclusions

Although morphologically normal, distinct cartilage degeneration may be present in young adult sheep cartilage. dGEMRIC can reveal these changes and may be a tool for the assessment of early cartilage degeneration.     

Endometrial cancer with cervical stromal invasion: diagnostic accuracy of diffusion-weighted and dynamic contrast enhanced MR imaging at 3T

Objectives

To compare the diagnostic accuracy of diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging for detecting cervical stromal invasion in endometrial cancer.

Methods

Eighty-three consecutive women with endometrial cancer underwent preoperative evaluation in a 3-T unit, including T2-weighted, DW (b?=?0 and 1000 s/mm²), and DCE MR imaging. Two radiologists independently assessed presence of cervical stromal invasion, with histopathological reference as gold standard.

Results

For assessing cervical stromal invasion, the diagnostic accuracy, sensitivity, and specificity, respectively for Reader 1/Reader 2, were as follows: DW MR imaging— 95.2 %/91.6 %, 91.7 %/100 %, and 95.8 %/90.1 %; DCE MR imaging— 91.6 %/88 %, 58.3 %/50 %, and 97.2 %/94.4 %. The diagnostic performance of DW MR imaging (Reader 1: areas under the receiver operating characteristic curve (AUC)?=?0.98; Reader 2: AUC?=?0.97) was significantly higher than that of DCE MR imaging (p?=?0.009 for Reader 2) or T2-weighted MR imaging (Reader 1: p?=?0.006; Reader 2: p?=?0.013). Patients with cervical stromal invasion showed a significantly greater canal width (p?<?0.0001) and myometrial invasion extent (p?=?0.006).

Conclusions

DW MR imaging has superior diagnostic performance compared with DCE MR imaging in the detection of cervical stromal invasion.

Key Points

? DWI demonstrates a higher accuracy than DCE in detecting cervical stromal invasion. ? Tumour ADC values are similar between patients without or with cervical invasion. ? Canal widening causes false-negativity on DCE and T2W but not on DWI.

     

MRI texture analysis of subchondral bone at the tibial plateau

Objectives

To determine the feasibility of MRI texture analysis as a method of quantifying subchondral bone architecture in knee osteoarthritis (OA).

Methods

Asymptomatic subjects aged 20–30 (group 1, n = 10), symptomatic patients aged 40–50 (group 2, n = 10) and patients scheduled for knee replacement aged 55–85 (group 3, n = 10) underwent high spatial resolution T1-weighted coronal 3T knee MRI.Regions of interest were created in the medial (MT) and lateral (LT) tibial subchondral bone from which 20 texture parameters were calculated. T2 mapping of the tibial cartilage was performed in groups 1 and 2. Mean parameter values were compared between groups using ANOVA. Linear discriminant analysis (LDA) was used to evaluate the ability of texture analysis to classify subjects correctly.

Results

Significant differences in 18/20 and 12/20 subchondral bone texture parameters were demonstrated between groups at the MT and LT respectively. There was no significant difference in mean MT or LT cartilage T2 values between group 1 and group 2.LDA demonstrated subject classification accuracy of 97 % (95 % CI 91–100 %).

Conclusion

MRI texture analysis of tibial subchondral bone may allow detection of alteration in subchondral bone architecture in OA. This has potential applications in understanding OA pathogenesis and assessing response to treatment.

Key Points

? Improved techniques to monitor OA disease progression and treatment response are desirable ? Subchondral bone (SB) may play significant role in the development of OA ? MRI texture analysis is a method of quantifying changes in SB architecture ? Pilot study showed that this technique is feasible and reliable ? Significant differences in SB texture were demonstrated between individuals with/without OA

     

Nitric oxide and blood pressure responses to short-term resistance training in adults with and without type-2 diabetes: a randomized controlled trial

Background

Type-2 diabetes (T2D) is associated with endothelial dysfunction, increase in sympathetic tone and several cardiovascular disorders, such as systemic arterial hypertension and coronary artery disease.

Aims

To determine the effects of resistance training (RT) on the responses of nitric oxide (NO) and blood pressure (BP) in individuals with T2D and their controls peers.

Methods

Randomized controlled trial in which T2D patients and non-diabetic individuals (ND) performed 8 weeks of RT. Participants were 22 women and 12 men (age 62.3?±?2.5 years) that were randomly allocated into four groups: T2D training (n?=?9), ND training (n?=?10), T2D control (n?=?8), and ND control (n?=?7). NO and BP were measured before and after the whole intervention.

Results

There were no significant differences in nitrite concentrations between and within groups, with values varying between 1.22?±?0.15 and 1.45?±?0.13 Log µM. The T2D and ND experimental groups decreased systolic blood pressure (SBP) by 8.1 and 1.4 mmHg, respectively. However, the control groups showed elevation of SBP (3.6 mmHg for T2D and 4.1 mmHg for ND). Although none of these changes were significant (p?>?0.05). In addition, T2D subjects who did not undergo the training increased diastolic blood pressure (p?=?0.030) and mean arterial pressure (p?=?0.054).

Conclusions

Eight weeks of RT does not increase NO bioavailability, and in turn, does not reduce BP in T2D patients—though it prevented its increase.

Trial registration

ensaiosclinicos.gov.br (ID: RBR-4d39z9).

     

Differentiation of malignant from benign soft tissue tumours: use of additive qualitative and quantitative diffusion-weighted MR imaging to standard MR imaging at 3.0 T

Objectives

To determine the added value of diffusion-weighted imaging (DWI) to standard magnetic resonance imaging (MRI) to differentiate malignant from benign soft tissue tumours at 3.0 T.

Methods

3.0 T MR images including DWI in 63 patients who underwent surgery for soft tissue tumours were retrospectively analyzed. Two readers independently interpreted MRI for the presence of malignancy in two steps: standard MRI alone, standard MRI and DWI with qualitative and quantitative analysis combined.

Results

There were 34 malignant and 29 non-malignant soft tissue tumours. In qualitative analysis, hyperintensity relative to skeletal muscle was more frequent in malignant than benign tumours on DWI (P=0.003). In quantitative analysis, ADCs of malignant tumours were significantly lower than those of non-malignant tumours (P≤0.002): 759±385 vs. 1188±423 μm²/sec minimum ADC value, 941±440 vs. 1310±440 μm²/sec average ADC value. The mean sensitivity, specificity and accuracy of both readers were 96 %, 72 %, and 85 % on standard MRI alone and 97 %, 90 %, and 94 % on standard MRI with DWI.

Conclusions

The addition of DWI to standard MRI improves the diagnostic accuracy for differentiation of malignant from benign soft tissue tumours at 3.0 T.

Key Points

? DWI has added value for differentiating malignant from benign soft tissue tumours. ? Addition of DWI to standard MRI at 3.0 T improves the diagnostic accuracy. ? Measurements of both ADC _min within solid portion and ADC _av are helpful.