Background and Aims: Disc displacement is the most common temporomandibular joint disorder and MAGNETIC RESONANCE imaging (MRI) is the gold standard in its diagnosis. This disorder can lead to changes in signal intensity of MAGNETIC RESONANCE (MR). The purpose of this study was evaluation of correlation between relative signal intensity of MR images of retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle with type of anterior disk displacement and condylar head flattening in patients with temporomandibular disorder (TMD).Materials and Methods: In this retrospective study, 31 MR images of patients who had anterior disc displacement were evaluated. After relative signal intensity measurement for retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle, the correlation between relative signal intensity and type of anterior disc displacement was evaluated with repeated measure ANOVA test. In each of these 3 areas, t-test was used to compare the groups with and without condylar head flattening.Results: The correlation between relative signal intensity of MR images and type of anterior disc displacement in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle was not significant. There was also no statistically significant correlation between relative signal intensity of MR images and flattening of condylar head in retrodiscal tissue, superior and inferior head of lateral ptrygoid muscle (P>0.05).Conclusion: According to findings of this study, relative signal intensity of MR images in retrodiscal tissue, superior and inferior head of ptrygoid muscle is not a good predictor for type of anterior disc displacement and flattening of condylar head. It seems that this cannot be used as a diagnostic marker for TMD progression.

BACKGROUND: According to recent studies comparing MAGNETIC RESONANCE ENTEROGRAPHY (MRE) with ileocolonoscopy for assessing inflammation of small bowel and colonic segments in adults with active Crohn’s disease (CD), we aimed to compare the accuracy of these two diagnostic methods in Iranian population.METHODS: During 2013-2014 a follow-up study was done on 30 patients with active CD in a gastroenterology clinic affiliated to Tehran University of Medical Sciences.MRE and ileocolonoscopy were performed for all the patients. All statistical analyses were performed using SPSS (version 18) andp -value<0.05 was considered as statistically significant.RESULTS: Of the 30 patients with active CD, 11 (36.7%) were men and 19 (63.3%) were women with mean age of 37.30±13.66 years (range: 19-67 years). MRE had sensitivity and specificity of 50% and 90% with positive predictive value (PPV) and negative predictive value (NPV) of 71.43 and 78.26, respectively for localizing sigmoid lesions and ileum had sensitivity and specificity of 84.21 and 45.45 with PPV and NPV of 72.73 and 62.50, respectively.CONCLUSION: While moderate sensitivity and high specificity of MRE in localizing colonic lesions makes it an appropriate confirmatory test after colonoscopy, the reported high sensitivity and moderate specificity of MRE versus colonoscopy in detecting ileal lesions makes it a suitable screening test for ileal lesions.Finally we can conclude that MRE can be an important complementary test to colonoscopy in detecting active disease.

Background: The goal of this study was to evaluate MAGNETIC RESONANCE (MR) ENTEROGRAPHY findings and assess the role of diffusion-weighted imaging (DWI) in patients suffering from active Crohn’s disease. Methods: This retrospective study included a total number of 76 patients diagnosed with active Crohn's disease, as established by the Crohn's Disease Activity Index (CDAI). The study consisted of 30 women and 46 men, ranging in age from 13 to 72 years. All participants underwent MR ENTEROGRAPHY with DWI sequences. The study was conducted at Imam Khomeini Hospital in Tehran between 2013 and 2018. The imaging modality utilized for the study included a 3-T SIGNA Excite MR ENTEROGRAPHY machine and a Siemens Magnetom 3-T MR imaging (MRI) machine. Results: Bowel wall restriction was observed in less than half of the patients, and no significant correlation was found with extramural findings such as mesenteric edema. The study did not reveal any meaningful association between diffusion restriction and specific mural enhancement patterns, mesenteric lymphadenopathy with or without enhancement, or the length of the affected segments (P> 0. 05). The most common findings observed in MRI were ileum thickness in 72. 4% of patients, mesenteric lymphadenopathy without enhancement in 46. 1%, ileocecal thickness in 42. 1%, DWI findings in 42. 1%, the presence of a comb sign in 36. 8%, and jejunum thickness in 30. 3% of patients. Conclusion: MRE findings are useful in the evaluation of Crohn’s disease activity.

Background: The study of the molecular dynamics of proteins based on internal motions is crucial for understanding the mechanism of protein function. Internal movements of proteins play an important role in both protein folding processes and the mechanism of action of enzyme. Knowledge about these movements will help us in understanding these processes correctly. Osmolites are small organic molecules which are utilized by the cells of all organisms, except hallobacteria. Osmolites are produced under extreme stressful conditions in order to help in stabilizing macro-molecules and retaining their biological function. They interact directly with macromolecules, but they exert their effect only when the characteristics or conditions of the solvent present around the cell change. Therefore, their presence affects the stability of the protein indirectly.Materials and Methods: In this work we studied the effect (s) of the osmolite Sorbitol on the dynamics of Hen Egg White Lysozyme, and through our study we used NMR Hydrogen-Deuterium Exchange to characterize the effect (s). We performed spectrometery in two different conditions, in the absence and presence of sorbitol. The extent of peptide hydrogen exchange was assigned as a function time and in a decreasing manner in the intensity of the peak corresponding to amino acids. The resulting TOCSY spectra were assigned using SPARKY software, as well as we integrated the peaks using this software.Results: The speed of hydrogen exchange, hydrogen atoms of the peptide bond, will give us information about the local structural oscillations where the exchange is taking place. The rate of hydrogen exchange varies from one amino acid to another, and the intensity of the peak of these hydrogen decreases as time passes by.Conclusion: We found that the presence of sorbitol causes a decrease in proton exchange rate, and since there is no noticeable chemical shifts in the peaks of the spectra, in the presence or absence of sorbitol, we can conclude that sorbitol did not cause any change in the three dimensional structure. It seems that the decrease in the rate of exchange is a representative of a decrease in the accessible surface area or to strengthening of hydrogen bonds, and sorbitol caused one of these two possibilities.

Tumor detection and isolation in MAGNETIC RESONANCE imaging (MRI) is a significant consideration, but when done manually by people, it is very time consuming and may not be accurate. Also, the appearance of the tumor tissue varies from patient to patient, and there are similarities between the tumor and the natural tissue of the brain. In this paper, we have tried to provide an automated method for diagnosing and displaying brain tumors in MRI images. Images of patients with glioblastoma were used after applying pre-processing and removing areas that have no useful information (such as eyes, scalp, etc.). We used a bounding box algorithm, to create a projection for to determining the initial range of the tumor in the next step, an artificial bee colony algorithm, to determine an initial point of the tumor area and then the Grow cut algorithm for, the exact boundary of the tumor area. Our method is automatic and extensively independent of the operator. comparison between results of 12 patients in our method with other similar methods indicate a high accuracy of the proposed method (about 98%) in comparison s.

Background: Differentiation between benign and malignant parotid tumors before surgery is important because it can change the therapeutic planning for patients. In this study we evaluated the role of MAGNETIC RESONANCE spectroscopy (MRS) in differentiation of benign from malignant parotid tumors. Materials and Methods: 40 patients entered with salivary gland tumor especially parotid) that candidated for surgery in this study. Patients selected in Amiralam hospital and did MRI in Imam Khomeini hospital. In this study, on these patients MAGNETIC RESONANCE spectroscopy (MRS) was performed at 135 and 270 Time of Echo, and the choline/creatine ratio was determined. Regarding to the cytological results, patient divided to warthin, benign and malignant tumors and ROC curves used to determine the best cut off points. Results: 40 patients entered in this study, 25 had benign non warthin tumors, 9 malignant tumors and 6 warthin tumors. In differentiation benign from malignant tumors TE136 was stronger. The best cut off point of Choline to Creatine ratio in TE: 136 was 1. 92 with sensitivity 81 % and specificity 89% and in TE 270 was 1. 76 with Sensitivity 89% and specificity 71%. Choline/creatine ratio <1. 25 can rule out the malignancy with sensitivity of 92% and ratio > 1. 76 strongly suggest malignancy (with10% specificity). MRS was not able to differentiate benign non warthin from warthin tumors. Conclusion: According to this study, Choline/ creatine ratio in MRSpectroscopy can be helpful as noninvasive method in differentiation of benign from malignant tumors.