Functional MRI in assessment of diabetic kidney disease in people with type 1 diabetes.

AIMS: To compare levels of renal hypoxia measured by Blood Oxygen Level Dependent (BOLD) magnetic resonance imaging (MRI) with measured transverse relaxation rate (R2*) and renal structural changes including apparent diffusion coefficient (ADC) and fractional anisotropy (FA) in patients with type 1 diabetes and healthy controls. METHODS: Cohort study comparing MRI metrics in type 1 diabetes (n = 32, GFR 105 (77, 120) ml/min.1.73m2) and controls (n = 10). Renal function and selected inflammatory renal biomarkers were also measured. RESULTS: For BOLD, we found reduced cortical [14.7 (13.7,15.8) (1/s) vs 15.7 (15.1,16.6) (1/s), p < 0.001] and medullary [24.8 (21.8,28.2) (1/s) vs. 29.3 (24.3,32.4) (1/s), p < 0.001] R2*, indicating more oxygenated parenchyma, in type 1 diabetes vs. controls, respectively. We observed reduced cortical FA, indicating decreased structural integrity in type 1 diabetes -0.04 (-0.07, -0.01), (p = 0.02). We found reduced cortical ADC, reflecting reduced water diffusion, in non-hyperfiltering [2.40 (2.29,2.53) (103mm2/s)] versus hyperfiltering [2.61 (2.53,2.74) (103mm2/s)] type 1 diabetes patients. MRI parameters correlated with renal function and inflammatory renal biomarkers. CONCLUSIONS: MRI derived indices of renal function and structure differed between (i) type 1 diabetes and healthy controls, and (ii) between non-hyperfiltering and hyperfiltering type 1 diabetes patients, providing insight into the role of hypoxia and renal structural, and functional changes in DKD.

Geometric Distortion Correction of Renal Diffusion Tensor Imaging Using the Reversed Gradient Method.

ABSTRACT: Renal echo planar diffusion tensor imaging (DTI) has clinical potential but suffers from geometric distortion. We evaluated feasibility of reversed gradient distortion correction in 10 diabetic patients and 6 volunteers. Renal area, apparent diffusion coefficient, fractional anisotropy, and tensor eigenvalues were measured on uncorrected and distortion-corrected DTI. Corrected DTI correlated better than uncorrected DTI (r = 0.904 vs 0.840, P = 0.002) with reference anatomic T2-weighted imaging, with no significant difference in DTI metrics.

MRI does not effectively diagnose ulnar-sided wrist pain in elite tennis players.

OBJECTIVES: Ulnar-sided injuries of the non-dominant wrist are common in elite tennis players using a double-handed backhand technique. This study investigated the radiological changes of the non-dominant wrist in elite symptomatic and asymptomatic players using this technique as well as healthy controls. We compared clinical findings to radiological abnormalities. DESIGN: Cross-sectional design with blinded radiological assessment, and contemporaneous clinical assessment of symptomatic players. METHODS: Magnetic resonance images (MRI) of wrists related to non-dominant ulnar-sided pain, were taken in 14 symptomatic tennis players, 14 asymptomatic tennis players, and 12 healthy controls which were then independently reviewed for abnormalities by blinded radiologists. Total abnormalities and global between-group differences in the triangular fibrocartilage complex (TFC), ulnar collateral ligament (UCL), extensor carpi ulnaris (ECU) and supporting structures, osseous-articular lesions and ganglia were assessed. These were then compared to clinical examinations of the symptomatic players to assess agreement. RESULTS: Symptomatic players reported a mean 3.64 abnormalities, being exactly 1 abnormality greater than asymptomatic players (2.64) and controls (2.50), suggesting similar asymptomatic lesions in all three groups. Players with pain reported significantly more osseous-articular lesions, ECU tendon and dorsal radio-ulnar ligament abnormalities, while changes to the UCL may reflect an isolated problem in specific wrists. There were no between-group differences in the presence of ganglia, most TFC structures nor ECU subsheath tear and subluxation. CONCLUSIONS: Clinicians should carefully consider radiological changes alongside their clinical diagnosis of non-dominant wrist pain in tennis players due to possible tennis-related changes and/or asymptomatic findings.

Do magnetic resonance imaging abnormalities of the non-dominant wrist correlate with ulnar-sided wrist pain in elite tennis players?

OBJECTIVE: Ulnar-sided injuries of the non-dominant wrist are common in elite tennis players that use the double-handed backhand technique. This study aimed to define the relationship between ulnar-sided wrist pain in symptomatic and asymptomatic elite tennis players, and the presence of abnormalities on magnetic resonance imaging (MRI). MATERIALS AND METHODS: Fourteen symptomatic tennis players, 14 asymptomatic tennis players, and 12 healthy controls who did not play tennis, were analyzed prospectively, after undergoing MRI of their non-dominant wrist. Five anatomical regions were analyzed, thought to relate to ulnar-sided wrist pain. These consisted of the triangular fibrocartilage complex (TFCC), ulnar collateral ligament (UCL), extensor carpi ulnaris tendon (ECU), osseous-articular structures, and ganglia. Images were independently reviewed by two blinded musculoskeletal radiologists. RESULTS: Non-dominant, ulnar-sided, wrist pain in elite tennis players was not statistically significantly associated with an increased number of MRI abnormalities when compared with asymptomatic tennis players (p > 0.05). However, some evidence of statistical association was seen with an increased prevalence of ECU tendon abnormalities (OR = 8.0, 95% CI = (0.74, 20.00), p = 0.07). A statistically significant increase in MRI abnormalities of osseous structures (OR = 15.1, 95% CI = (1.56, 656.05), p = 0.02) and the dorsal radioulnar ligament (DRUL) (OR = 12.5, 95% CI = (2.15, 111.11), p = 0.03), was observed in symptomatic players compared with controls. CONCLUSIONS: Non-dominant, ulnar-sided, wrist pain in a subgroup of elite tennis players using a double-handed backhand technique is not associated with a statistically significant increased prevalence of MRI abnormalities when compared with asymptomatic tennis players, other than some evidence of statistical association with ECU tendon abnormalities. Therefore, significance of MRI abnormalities should be interpreted in the context of clinical findings.

A semi-automated "blanket" method for renal segmentation from non-contrast T1-weighted MR images.

OBJECTIVE: To investigate the precision and accuracy of a new semi-automated method for kidney segmentation from single-breath-hold non-contrast MRI. MATERIALS AND METHODS: The user draws approximate kidney contours on every tenth slice, focusing on separating adjacent organs from the kidney. The program then performs a sequence of fully automatic steps: contour filling, interpolation, non-uniformity correction, sampling of representative parenchyma signal, and 3D binary morphology. Three independent observers applied the method to images of 40 kidneys ranging in volume from 94.6 to 254.5 cm(3). Manually constructed reference masks were used to assess accuracy. RESULTS: The volume errors for the three readers were: 4.4% ± 3.0%, 2.9% ± 2.3%, and 3.1% ± 2.7%. The relative discrepancy across readers was 2.5% ± 2.1%. The interactive processing time on average was 1.5 min per kidney. CONCLUSIONS: Pending further validation, the semi-automated method could be applied for monitoring of renal status using non-contrast MRI.

Endometriosis: Does the menstrual cycle affect magnetic resonance (MR) imaging evaluation?

PURPOSE: To determine if the menstrual cycle affects MR interpretation in patients with pelvic endometriosis. MATERIALS AND METHODS: Thirty-one patients with either laparoscopically proven endometriosis, or a high clinical suspicion of deep infiltrative endometriosis, were prospectively recruited from May 2008 to October 2009 and January to June 2012. Two pelvic MR scans were performed for pre-operative planning; during menses and the other mid-cycle. Two experienced radiologists independently assessed image quality and disease extent. Both were blinded to patient identity, previous imaging and menstrual status. Interobserver agreement was assessed using the Kappa (k) test. Descriptive statistics were prepared using chi-squared (or Fishers' exact) tests and Mann-Whitney (rank sum) tests to assess for significant differences between menstrual and non-menstrual imaging. RESULTS: Interobserver agreement for image quality was moderate for T2 weighted imaging (k=0.475, p-value <0.001) and substantial for T1 fat saturated imaging (k=0.733, p-value<0.001), with no significant difference in image quality between menstrual and non-menstrual scans (all p-values>0.255). Readers demonstrated at least moderate interobserver agreement for certainty level of endometriosis at site-specific locations, with median k 0.599 (IQR 0.488-0.807). No significant difference in disease extent was observed between menstruating and non-menstruating scans (all p-values>0.05). CONCLUSION: Findings suggest no significant differences in image quality, disease extent or disease severity between menstruating and non-menstruating MR; thus, timing of pelvic MR for assessment of endometriosis need not be influenced by the menstrual cycle.