ABSTRACT
The objective was to investigate if some of the key molecular players associated with bladder hyper-permeability in interstitial cystitis/bladder pain syndrome (IC/BPS) could be visualized with molecularly-targeted magnetic resonance imaging (mt-MRI) in vivo. IC/BPS is a chronic, painful condition of the bladder that affects primarily women. It has been demonstrated over the past several decades that permeability plays a substantial role in IC/BPS. There are several key molecular markers that have been associated with permeability, including glycolsaminoglycan (GAG), biglycan, chondroitin sulfate, decorin, E-cadherin, keratin 20, uroplakin, vascular endothelial growth factor receptor 1 (VEGF-R1), claudin-2 and zonula occludens-1 (ZO-1). We used in vivo molecularly-targeted MRI (mt-MRI) to assess specific urothelial biomarkers (decorin, VEGF-R1, and claudin-2) associated with bladder hyper-permeability in a protamine sulfate (PS)-induced rat model. The mt-MRI probes consisted of an antibody against either VEGF-R1, decorin or claudin-2 conjugated to albumin that had also Gd-DTPA (gadolinium diethylene triamine penta acetic acid) and biotin attached. mt-MRI- and histologically-detectable levels of decorin and VEGF-R1 were both found to decrease following PS-induced bladder urothelial hyper-permeability, whereas claudin-2, was found to increase in the rat PS model. Verification of the presence of the mt-MRI probes were done by targeting the biotin moiety for each respective probe with streptavidin-hose radish peroxidase (HRP). Levels of protein expression for VEGF-R1, decorin and claudin-2 were confirmed with immunohistochemistry. In vivo molecularly-targeted MRI (mt-MRI) was found to successfully detect alterations in the expression of decorin, VEGFR1 and claudin-2 in a PS-induced rat bladder permeability model. This in vivo molecularly-targeted imaging approach has the potential to provide invaluable information to enhance our understanding of bladder urothelium hyper-permeability in IC/BPS patients, and perhaps be used to assist in developing novel therapeutic strategies.
ABSTRACT
The standard method for measuring the slice thickness of magnetic resonance images uses the inclined surface of a wedge (wedge method); it is sensitive to small increases in noise because of the differentiation of the edge response function (ERF) required. The purpose of this study was to improve the wedge method by fitting a curve to the ERF. The curve-fit function was obtained by convolving an ideal ERF (a ramp function) with a Gaussian function to represent ERF blurring. Measurements of 5- and 3-mm slice thicknesses were performed on a 3T scanner using the conventional wedge method, the improved wedge method, and another standard method using an inclined slab (slab method). Subsequently, 0.5- and 0.25-mm slice thicknesses from multiple slices acquired using a three-dimensional sequence were measured using the improved wedge method. When measuring 5-mm slices, the differences in measurements obtained using the improved wedge method and the conventional slab and wedge methods were very small: <0.6% of the 5-mm slice thickness. The difference was ≤1.7% for 3-mm slices. For 0.5- and 0.25-mm slices, the mean values obtained using the improved wedge method were 0.543 ± 0.007 mm and 0.247 ± 0.015 mm, with a 1.2 and 5.9% coefficient of variation across slices, respectively. The improved wedge method is valid and potentially applicable to the measurement of sub-millimeter slice thicknesses.
Subject(s)
Image Processing, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Magnetic Resonance Imaging/instrumentation , Magnetic Resonance Imaging/methods , Phantoms, Imaging , HumansABSTRACT
Objective To study the clinical value of wrist magnetic resonance imaging (MRI) combined anti-cyclic citrullinated peptide antibody detection in the diagnosis of early rheumatoid arthritis (RA).Methods Forty five patients with early RA were selected as RA group,45 cases of patients without rheumatoid arthritis as non-RA group,and 43 cases of people with normal examination as control group.All subjects were given wrist MRI and anti-cyclic citrullinated peptide (CCP) antibody with the enzyme linked immunosorbent assay (ELISA).At the same time,clinical symptoms,physical signs,MRI manifestations,and laboratory indicators were collected.All results were statistically analyzed.Results Positive rate of MRI lesions and serum anti-CCP antibody in RA group were significantly higher than non-RA group and control group (P ＜0.05).The sensitivity and specificity of MRI (or anti-CCP antibody) for early RA were 88.88％ and 82.22％ (or 68.88％ and 91.11％).The sensitivity (64.44％) of MRI combined with anti-CCP antibody was decreased compared to individual; however,the specificity (100％) of MRI combined with anti-CCP antibody was increased.The correlation of MRI synovial scores and anti-CCP antibody levels was positively correlated (rs =0.612,P ＜ 0.05).MRI abnormal signs and joint disease activity score (DAS28) were positively correlated (rs =0.521,P ＜ 0.05).Anti-CCP antibody levels and DAS28 were positively correlated (rs =0.541,P ＜ 0.05).Conclusions MRI examination and combined with anti-CCP antibody detection is helpful to improve the diagnosis of early RA,and it provides a detection basis for dynamic assessment of RA condition changes.
ABSTRACT
PURPOSE: To evaluate the use of the intravoxel incoherent motion (IVIM) technique in half-Fourier single-shot turbo spin-echo (HASTE) diffusion-weighted imaging (DWI), and to compare its accuracy to that of apparent diffusion coefficient (ADC) to predict malignancy in head and neck tumors. PATIENTS AND METHODS: HASTE DW images of 33 patients with head and neck tumors (10 benign and 23 malignant) were evaluated. Using the IVIM technique, parameters (D, true diffusion coefficient; f, perfusion fraction; D*, pseudodiffusion coefficient) were calculated for each tumor. ADC values were measured over a range of b values from 0 to 1000s/mm(2). IVIM parameters and ADC values in benign and malignant tumors were compared using Student's t test, receiver operating characteristics (ROC) analysis, and multivariate logistic regression modeling. RESULTS: Mean ADC and D values of malignant tumors were significantly lower than those of benign tumors (P<0.05). Mean D* values of malignant tumors were significantly higher than those of benign tumors (P<0.05). There was no significant difference in mean f values between malignant and benign tumors (P>0.05). The technique of combining D and D* was the best for predicting malignancy; accuracy for this model was higher than that for ADC. CONCLUSIONS: The IVIM technique may be applied in HASTE DWI as a diagnostic tool to predict malignancy in head and neck masses. The use of D and D* in combination increases the diagnostic accuracy in comparison with ADC.
