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.

The main focus of the present study is to investigating the sex differences in L1 and L2 Number and Person Phi-features processing of bilinguals. To achieve this goal, the performance of thirty balanced Turkish-Persian bilinguals (15 women) who had learned Persian at school entry, was evaluated by event-related Functional Magnetic Resonance Imaging ((fMRI)). Both groups displayed significant activation of the Pars opercularis only for the Number feature, whereas the posterior Superior Temporal Gyrus was activated for both Number and Person features. Importantly, no difference was observed in the brain activation patterns in men and women in processing Number or Person Phi-features. In general, our results suggest that Number and Person Phi-features processing may not be influenced by sex differences, age of acquisition or the interaction of these factors, arguing for an indistinguishable syntactic competence of both genders in L1 and L2 for balanced bilinguals.

Pre-operative determination of the dominant hemisphere for speech and speech associated sensory and motor regions has been of great interest for the neurological surgeons. This dilemma has been of at most importance, but difficult to achieve, requiring either invasive (Wada test) or non-invasive methods (Brain Mapping). In the present study we have employed Functional Magnetic Resonance Imaging ((fMRI)) to observe and delineate regional brain activations during execution of language related tasks. Our healthy volunteers comprised of 10 right-handed males (handedness being ascertained by “Snyder-Harris Handedness Inventory”) all speaking Persian as their native language. All the subjects performed two consequent language tasks namely “Word Generation” and” Reverse Word Reading”. The visual stimulation was performed employing a video projector and the presentation software, while the brain activity was monitored and studied by (fMRI). The stimuli were given during the activation period, while the asterix had been used as the blank (rest period). The subject response was internal speech. The (fMRI) method employed, was Echo Planar Imaging (EPI) using FSL as the analyzing software. The Hardware comprised of 1.5 Tesla GE brand MRI scanner. The brain regions involved language processing could be successfully and prominently activated with the aforementioned tasks (percent activity 1.2% and P<0.005). In all of the ten subjects being examined, these regions were exclusively located in the left hemisphere corresponding to Broca, Wernicke, and Exner areas. These promising results may be of value to determine the dominant hemisphere by a non-invasive method, or as an adjunct to conventional methods of Electrocortical Mapping and Wada test. Besides, the presented visual tasks could specifically activate the traditional language centers even those known to be involved in writing (Exner area). Estimation of the exact sensitivity and specificity of the methods requires employing a gold standard methods and larger subject populations.

Background: Prostate cancer is the third leading cause of death and is the most common cause of cancer in elderly men. Regarding to the low accuracy of screening methods such as prostate-specific antigen (PSA), Digital Rectal Examination (DRE) and trans rectal ultrasound (TRUS) in detection and localization of tumor, Magnetic Resonance Imaging (MRI) and Diffusion Weighted Imaging (DWI) attracted many attentions in the past years. DWI reveals micro-molecular diffusion, which is the Brownian motion of the spins in biologic tissues. This technique can delineate pathologic lesions with high tissue contrast against generally suppressed background signal. In this paper, the value of DWI in detection of prostate cancer is studied.Methods: In this cross-sectional study, the studied population are suspicious patients to prostate cancer based on high Prostatic Specific Antigen level or abnormal Digital Rectal Examination who refered for prostate biopsy to radiology department of Hazrate- Rasoul Hospital during the year 2011. The results of DWI are compared to biopsy results for all patients.Results: Eighty five patients are selected. The DWI sensitivity in detecting of prostate cancer is 100%, specificity 97.1% and positive and negative predictive values are 89.5% and 100%, respectively. The results showed that if DWI reports the prostate cancer as negative, the result was highly reliable and if it reports as positive, although the report was not 100% reliable, but it still had high reliability, more than 90%.Conclusion: DWI had high accuracy in detecting prostate cancer for patients with cancer. Also the accuracy of this method for patients without prostate cancer was acceptable compared to the other common methods.

Objective: This research has been conducted to detect and measured brain motor cortex activity of 25 normal volunteers during wrist flexion–extension task using optimized Gradient Echo–Planar Imaging (GR– EPI) technique by measuring blood oxygen level dependent changes in MR signal.Subjects and Methods: Scanning was performed on a 1.5 T General Electric MR Scanner (Signa Model) at Naft Grand Hospital. An optimized gradient echo T2*- weighted echo–planar sequence was used with the following parameters FOV=24 cm, NEX=1, TR=2000ms, TE=55 ms, Flip Angle=90o, Matrix Size=128 * 128 and Thickness=5 mm.One hundred and twenty axial images were acquired serially using a block design during rest and wrist flexion–extension task from the motor cortex area of the wrist around Sulcus of Rolando. Acquired images reformatted from DICOM Dicom to Analyze using MRIcro and underwent complex image processing and analysis using SPM2 and MATLAB (Ver. 7).Results: The results showed a significant increase (P£0.05) in S signal intensity of brain motor cortex during the task in comparison with the rest state. Activated areas in brain cortex were shown as clusters of 153 to 185 pixels in size (165.12±9.93).Conclusion: The findings of this study may be used to evaluate the changes of brain cortex activity in various diseases and also to assess the respond to treatment procedures.

Introduction: This study aimed to assess the effect of controlled mouth breathing during the resting state using Functional Magnetic Resonance Imaging ((fMRI)). Methods: Eleven subjects participated in this experiment in which the controlled “, Nose”,and “, Mouth”,breathings of 6 s respiratory cycle were performed with a visual cue at 3T MRI. Voxel-wise seed-to-voxel maps and whole-brain region of interest (ROI)-to-ROI connectome maps were analyzed in both “, Nose>Mouth”,and “, Mouth>Nose”,contrasts. Results: As a result, there were more connection pairs in the “, Mouth”,breathing condition, i. e., 14 seeds and 14 connecting pairs in the “, Mouth>Nose”,contrast, compared to 7 seeds and 4 connecting pairs in the “, Nose>Mouth”,contrast (false discovery rate [FDR] of P<0. 05). Conclusion: The present study demonstrated that mouth breathing with controlled respiratory cycles could significantly induce alterations in Functional connectivity in the resting-state network, suggesting that it can differently affect resting brain function,in particular, the brain can hardly rest during mouth breathing, as opposed to conventional nasal breathing.

Introduction As Functional Magnetic Resonance Imaging ((fMRI)) is too expensive and time consuming, its frequent implementation is difficult. The aim of this study is to evaluate repeatability of detecting visual cortex activity in (fMRI).Materials and Methods In this study, 15 normal volunteers (10 female, 5 male; Mean age±SD: 24.7±3.8 years) attended. Functional Magnetic Resonance images were obtained during a visual task of sine-wave with spatial frequency of 1.84 cpd and temporal frequency of 8 Hz in three scan runs. Two runs of Functional images were provided consecutively in a session, and the third run was provided 1-6 weeks later. The activation map was created using the data obtained from the block-designed (fMRI) study. Voxels whose Z value was above a threshold of 2.3, at a significance level p=0.05, were considered activated. After image processing, the blood oxygen level dependent (BOLD) signal changes and the number of activated voxels in response to visual stimuli were compared in different runs.Results The results of this study demonstrate no significant difference between the number of activated voxels and BOLD signal in first and second runs in one session (Paired t-test, p>0.05). Moreover, there is a considerable correlation between first and second scan runs (rsignal=0.74, p=0.006 and rvoxel=0.62, p=0.03), while the correlation between the runs in separate sessions is weak (rsignal=0.28, p=0.38 and rvoxel=0.32, p=0.31).Conclusion Since the repeatability of BOLD signal and number of activated voxels in one session is considerably better than that in the separate sessions, it is suggested that in (fMRI) visual studies that need repeated scanning, scans should be acquired during a single session.