Diffusion Weighted Magnetic Resonance Imaging in the Assessment of Renal Function and Parenchymal Changes in Chronic Kidney Disease: A Preliminary Study.

BACKGROUND The aim of this study was to evaluate the feasibility of using intravoxel incoherent motion (IVIM) imaging for noninvasive assessment of pathologic changes in chronic kidney disease (CKD). MATERIAL AND METHODS Thirty-four patients with CKD and 20 healthy volunteers were examined on a 1.5 T magnetic resonance imaging (MRI) unit. The examination consisted of morphologic sequences and diffusion-weighted echo-planar sequence with 10 b values. Diffusion parameters were calculated with the use of mono- (apparent diffusion coefficient, ADC) and bi-exponential model: pure diffusion coefficient (D) and perfusion fraction (Fp). Blood samples to assess the serum creatinine level were taken immediately before examination. Ultrasound guided biopsies were performed in less than 30 days from MRI and were scored by an experienced nephropathologist. Parametrical unpaired t-test and ROC curve analysis were used to investigate differences in diffusion parameters in relation to estimated glomerular filtration rate (eGFR). Pearson's correlation coefficients were calculated to assess relationship between diffusion parameters and laboratory and histopathological markers of renal damage. P-value <0.05 indicated statistical significance. RESULTS Both ADC and D correlated positively with eGFR (respective r 0.74 and 0.72), however D showed a more significant correlation with histopathology: while D correlated negatively with parameters reflecting chronic glomerular (r -0.48) and tubulo-interstitial changes (r -0.47), ADC correlated only with interstitial infiltrations (r -0.44). Flow-related diffusion parameters showed high standard deviation. CONCLUSIONS IVIM imaging is sensitive to functional and morphologic changes in CKD. The separation of influence of Fp from true diffusion improves the assessment of chronic changes in renal parenchyma.

Diagnostic Benefits of Axial-Loaded Magnetic Resonance Imaging Over Recumbent Magnetic Resonance Imaging in Obese Lower Back Pain Patients.

STUDY DESIGN: Single center before-after case series study. OBJECTIVE: To determine when and in which kind of lower back pathologies, axial-loaded magnetic resonance imaging (MRI) provides additional benefit over recumbent MRI. SUMMARY AND BACKGROUND DATA: Systems simulating physiological axial loading of the spine in patients examined in the supine position have recently been introduced in clinical practice. However, indications for examinations with axial loading have yet to be clearly specified. METHODS: Ninety patients (46 men, 44 women, aged 20-90 yr) with lower back pain underwent lumbar spine MRI with and without axial loading. MRI was performed in a supine position on a 1.5 T system using a compression device. A high-resolution 3D T2-weighted sequence was used for image acquisition. Clinical characteristics of patients were established using questionnaire surveys and demographic data. MR images were assessed for the appearance of changes after axial loading. After determining which patients showed significant changes, logistic regression analysis was performed with 15 independent variables (clinical, demographic, and imaging-related). RESULTS: After axial loading, 48.9% of patients showed additional changes. Multivariate analysis revealed that only obesity was a statistically significant predictor of the occurrence of changes (P < 0.05). After axial loading, 11 potentially clinically relevant changes appeared in seven patients, the most common being absolute spinal stenosis (n = 7). CONCLUSION: Axial loading may increase the diagnostic value of lumbar spine MRI in patients with obesity and/or those with suspected spinal canal stenosis. LEVEL OF EVIDENCE: 4.

Mercury toxicity presenting as chronic fatigue, memory impairment and depression: diagnosis, treatment, susceptibility, and outcomes in a New Zealand general practice setting (1994-2006).

In a group of 465 patients diagnosed as having chronic mercury toxicity (CMT), 32.3% had severe fatigue, 88.8% had memory loss, and 27.5% had depression. A significant correlation was found between CMT and the Apo-lipoprotein E4 genotype (p=0.001). An investigation into an additional 864 consecutively seen general practice patients, resulted in 30.3% having evidence consistent with CMT, and once again a significant correlation was found with the APO-E4 genotype (p=0.001). Removal of amalgam mercury fillings when combined with appropriate treatment resulted in a significant symptom reduction (p<0.001) to levels reported by healthy subjects.

Apolipoprotein E genotyping as a potential biomarker for mercury neurotoxicity.

Apolipoprotein-E (apo-E) genotyping has been investigated as an indicator of susceptibility to heavy metal (i.e., lead) neurotoxicity. Moreover, the apo-E epsilon (epsilon)4 allele is a major risk factor for neurodegenerative conditions, including Alzheimer's disease (AD). A theoretical biochemical basis for this risk factor is discussed herein, supported by data from 400 patients with presumptive mercury-related neuro-psychiatric symptoms and in whom apo-E determinations were made. A statistically relevant shift toward the at-risk apo-E epsilon4 groups was found in the patients p<0.001). The patients possessed a mean of 13.7 dental amalgam fillings and 31.5 amalgam surfaces. This far exceeds the number capable of producing the maximum identified tolerable daily intake of mercury from amalgam. The clinical diagnosis and proof of chronic low-level mercury toxicity has been difficult due to the non-specific nature of the symptoms and signs. Dental amalgam is the greatest source of mercury in the general population and brain, blood and urine mercury levels increase correspondingly with the number of amalgams and amalgam surfaces in the mouth. Confirmation of an elevated body burden of mercury can be made by measuring urinary mercury, after provocation with 2,3,-dimercapto-propane sulfonate (DMPS) and this was measured in 150 patients. Apo-E genotyping warrants investigation as a clinically useful biomarker for those at increased risk of neuropathology, including AD, when subjected to long-term mercury exposures. Additionally, when clinical findings suggest adverse effects of chronic mercury exposure, a DMPS urine mercury challenge appears to be a simple, inexpensive procedure that provides objective confirmatory evidence. An opportunity could now exist for primary health practitioners to help identify those at greater risk and possibly forestall subsequent neurological deterioration.