Diffusion-weighted imaging in the assessment of renal function in patients with diabetes mellitus type 2.

OBJECTIVE: Investigation of functional magnetic resonance (MR) imaging role in early diagnosis of diabetic nephropathy (DN) in patients with diabetes mellitus (DM) type 2, by quantification of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values. MATERIAL AND METHODS: 10 healthy volunteers and 91 DM type 2 patients were scanned using diffusion-weighted imaging (DWI) and diffusion tensor imaging (DTI) sequences. Patients were divided into four groups based on the estimated glomerular filtration value (eGFR). ADC and FA values, calculated in six regions of interest in each kidney (cortex and medulla), were compared to eGFR and laboratory parameters of renal function. RESULTS: ADC values of DM patients were higher in the cortex than in the medulla (p < 0.01), while FA values were higher in the medulla (p = 0.284). Creatinine, cystatin C negatively correlated with ADC (cortex, medulla, parenchyma). Medullary FA were lower in DM patients and positively correlated with the eGFR (p = 0.049). Tractography showed disturbed structure in patients with impaired renal function. DISCUSSION: Medullary FA value is a more sensitive parameter than parenchymal ADC in the early detection of renal damage in DM patients. ADC and FA values are significant in the diagnosis of DN; further research is needed for the update and refinement of the established recommendations.

Diagnostic value of the apparent diffusion coefficient in differentiating malignant from benign endometrial lesions.

Introduction: Magnetic resonance imaging (MRI) with its innovative techniques, such as diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC), increases the diagnostic accuracy in distinguishing between malignant and benign lesions of the endometrium. The aim of the study was MRI differentiation between malignant and benign endometrial lesions and correlation with histopathological findings with a special emphasis on quantitative analysis. An additional aim was to correlate the ADC values and histological tumor grades. Methods: The prospective study included 119 female patients with or without vaginal bleeding and pathological values of endometrial thickness, who underwent MRI examinations. According to MRI reports the patients were divided into 45 suspicious malignant and 74 suspicious benign endometrial lesions. The radiological diagnosis was compared to the histopathological evaluation, which confirmed 37 malignant lesions while the rest were benign. Results: The mean ADC value for malignant lesions was 0.761 ± 0.13×10-3 mm2/s and for benign lesions was 1.318 ± 0.20×10-3 mm2/s. The ADC values for malignant lesions were expectedly lower than those of benign lesions (p<0.001). The ADC cut-off value was 1.007×10-3 mm2/s with a sensitivity of 100%, specificity of 92.7%, a positive predictive value of 60.3%, and a negative predictive value of 100%. In comparison with the histopathological findings, the sensitivity of MRI was 100%, specificity 90.2%, positive predictive value was 82.2%, and negative predictive value was 100%. Observing the histological grades 1, 2, and 3 of endometrial carcinoma, no statistically significant differences of mean ADC values were found. The mean ADC values for histological tumor grades 1,2 and 3 were 0.803 ± 0.13×10-3 mm2/s, 0.754 ± 0.12×10-3 mm2/s and 0.728 ± 0.13×10-3 mm2/s, respectively. Conclusion: DWI and ADC values represent clinically useful tools for the differentiation between malignant and benign endometrial lesions with high sensitivity and good specificity, but the results failed to demonstrate their usefulness in differentiating histological grades of endometrial cancer.

Diagnostic quality assessment of compressed SENSE accelerated magnetic resonance images in standard neuroimaging protocol: Choosing the right acceleration.

PURPOSE: To investigate the impact of compressed sensing - sensitivity encoding (CS-SENSE) acceleration factor on the diagnostic quality of magnetic resonance images within standard brain protocol. METHODS: Three routine clinical neuroimaging sequences were chosen for this study due to their long acquisition time: T2-weighted turbo spin echo (TSE), fluid - attenuated inversion recovery (FLAIR), and 3D time of flight (TOF). Fully sampled reference scans and multiple prospectively 2x to 5x undersampled CS scans were acquired. Retrospectively, undersampled scans were compared to fully sampled scans and visually assessed for image quality and diagnostic quality by three independent radiologists. RESULTS: Images obtained with CS-SENSE accelerated acquisition were of diagnostically acceptable quality at up to 3x acceleration for T2 TSE (average qualitative score 3.53 on a 4-point scale, with the acquisition time reduction of 64%), up to 2x for FLAIR (average qualitative score 3.27, with the acquisition time reduction of 43%) and 4x acceleration for 3D TOF sequence (average qualitative score 3.13, with the acquisition time reduction of 73%). There were no substantial differences between the readers' diagnostic quality scores (p > 0.05). CONCLUSIONS: CS-SENSE accelerated T2 TSE, FLAIR, and 3D TOF sequences of the brain show image quality similar to that of conventional acquisitions with reduced acquisition time. CS-SENSE can moderately reduce scan time, providing many benefits without losing the image quality.