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.

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.

Prostate cancer continues to be diagnosed with increasing frequency. MRI has an important role in the diagnosis, staging and follow-up of prostate cancer. The advent of the endorectal coil for high-resolution imaging of the prostate was hailed as a major achievement in prostate cancer imaging. MR spectroscopy (MRS) is a valuable tool that significantly increases the detection rate of prostate cancer and helps to make correct diagnosis of equivocal lesions in MRI. In MRS, magnetic resonance signals of small molecular-weight metabolites that reside in tissues are revealed. The metabolites visualized in MRS are identified by their resonance frequency, which is based on the chemical environment of hydrogen atoms. Each metabolite resonates at a different frequency, often referred to as chemical shift, which is measured in parts per million (ppm). In prostate MRS, several key metabolic resonances are identifiable. Principle among these is that of citrate, a metabolite found in relatively high concentrations in the prostate tissue owing to its presence in prostatic secretions. The citrate resonance is found at 2.6 ppm. Other resonances of interest are creatine and choline, the latter being a metabolite that is often elevated in malignant tissue. These metabolites resonate at 3.0 and 3.2 ppm, respectively. Depending on the quality of the prostate MRS examination, these resonance peaks may overlap partially.As such, distinct choline and creatine resonances may merge and may be hard to identify as separate peaks in the MR spectra. In MRS, the location of the spectrum or spectra in question is usually identified by a box or grid overlaid on an anatomic image. MRS can be performed as a single voxel over a specified lesion, or it can be performed to obtain multiple spectra from a two-dimensional or three-dimensional grid. A three-dimensional MRS grid is the best method of prostate MRS to encompass the entire prostate. MRS of the prostate allows the reader to obtain metabolic information from distinct regions of the prostate gland. Because normal and cancerous prostate tissue contains distinct MR spectral signatures, the information from MRS can be used to supplement that of MRI to identify areas of tumor involvement in the prostate.MRS in conjunction with conventional MRI increase the number of detected cancers compared to standard MRI alone. Using MRS as a supplement to conventional T2W MRI may improve the overall tumor depiction, which in turn improves the reader’s confidence in identifying the foci of the extra capsular disease associated with smaller tumors that may have been missed on conventional T2W imaging alone. Thus, incorporation of MRS with MRI improves the overall staging by distinguishing between organ-confined and extra capsular spread of disease. In this presentation I will demonstrate the results of prostate spectroscopy of 67 patients performed during the last 6 months.

Background: Molecular imaging is a new method of imaging of physiological studies at the cellular and sub-cellular levels. Among the various techniques that have been introduced for this purpose, magnetic resonance spectroscopy has provided an opportunity for study of brain activity and tumors in different areas of the body.Materials and Methods: In this review, using keywords such as MRS, Molecular imaging and Cancer at scientific databases such as PUBMED and ISI, studies in the field of MRS and related findings were evaluated.Results: MRS provides an opportunity to study brain disorders such as Alzheimer's and brain cancers. This method has also been used in diagnosis (between normal and cancerous tissues, different types of cancers and non-neoplastic from neoplastic), designing the most appropriate treatment regimen for each patient and also monitoring patient after treatment.Conclusion: MRS is a new method in molecular imaging that can be used in a variety of cancer diagnoses. This method can cover disadvantage of MRI procedure in evaluation of the tumor pathology.

Background: Proton magnetic resonance spectroscopy (MRS) is a well-known device for analyzing the biological fluids metabolically. Obtaining accurate and reliable information via MRS needs a homogeneous magnetic field in order to provide well-defined peaks and uniform water suppression. There are lots of reasons which can disturb the magnetic field homogeneity which can be corrected by a process known as shimming. This study is intended to recall the importance of shimming and also the significant role of quality control (QC) in achieving an accurate quantification. Methods: An acrylic cylindrical quality control phantom was designed as an analog of brain MRS test phantoms in order to control the accuracy of the obtained signal of a 1. 5 T Siemens MRI system which belonged to one of Shiraz hospitals. The signal of NAA, Cho, Cr, the combination of these metabolites and also the distilled water, which was used in this study, was evaluated using separate phantoms. A QC test was performed using Siemens QC phantom and a standard test phantom. Results: The spectrum of our home-madephantomhada significant difference with the expectedspectrum. The results of checking the spectrum of metabolites separately also confirmed that there was a systemic problem that affects all the signals originated from all metabolites and even the pure distilled water. The MRS system could not pass QC tests, and peak broadening was common in all spectra. The complex spectrum of standard test phantom was not produced successfully by the MRS system. Conclusions: By a simple check of the water peak characteristics, lots of information can be obtained, one of which is the status of shimming that has a considerable effect on the accuracy of the spectrum. Thus, performing an automatic or manual shimming is not a criterion of the spectrum accuracy, and performing a periodic quality control using a test phantom by a specialist is necessary. Briefly, the quality control of MRS and all the other clinical device must be taken seriously. Sometimes QC can be the boundary of a right or a wrong decision for the patient.

Introduction: The patients with polyps and ulcerative colitis diagnosis are more susceptible to colorectal cancer. So far, the diagnosis of colorectal diseases has been dependent on invasive procedures, such as sigmoidoscopy and colonoscopy. However, some recent research has been initiated for early diagnosis of colon cancer by using1H nuclear magnetic resonance (1H NMR) spectroscopy and chemometrics methods. In this study, spectrum results of patients and samples of normal subjects were compared.Materials and Methods: Participants who referred for colonoscopy (n=40) filled a consent form. They had received liquid diets for last 72 hours. Blood samples were collected in heparinized tubes. Samples were collected from patients who were diagnosed with polyps and also normal subjects. The separated plasma samples were sent for 1HNMR spectroscopy using CPMG Spin-echo methods. The samples were analyzed using ProMetab software, with performance of Principle Component Analysis. The different metabolites were identified by their chemical shifts.Results: There were 1624 metabolites in each spectrum. Effective metabolites were detected using Human Metabolome Data Base and effective metabolic cycle were determined using metaboanalyst Data Base.Conclusion: These findings indicated that the metabolism of amino acid tRNA synthase, histidine, cyanoamine and thiamine are the main differentiating metabolic cycles involved in the production of colorectal polyp.

Background: Considering the non-invasive nature of magnetic resonance spectroscopy (MRS) and its ability to detect prostate lesions, the present study aimed to investigate the accuracy of MRS techniques in distinguishing between prostate cancer (PCa) and prostatitis. Methods: Thirty-three patients (18 patients with PCa and 15 patients with prostatitis) were recruited for this study. Magnetic resonance imaging (MRI) and MRS were performed using 1. 5-T system GE-modle Optima 450 Discovery (GE Medical Systems, US). The (Cho+Cr)/Cit ratio of hypointense T2 areas were calculated. The diagnostic accuracy including sensitivity and specificity indices, with 0. 95 confidence interval as well as PPV and NPV were calculated for each variable. The receiver operating characteristic (ROC) area under the curve (AUC) was outlined and investigated. The mean quantitative values between the two groups (PCa and Prostatitis) were compared using independent t test. Results: The mean ratios of Cho+Cr/Cit in PCa was 1. 54 ± 0. 63 and 0. 83 ± 0. 48 for PCa and prostatitis, respectively, indicating a significant statistical difference (P = 0. 00). A reduction in citrate was seen in both PCa and prostatitis tissue. Significant elevation in choline peak was shown for PCa. Moreover, creatinine level was low in both normal tissue and PCa without significant difference. Sensitivity, specificity, accuracy, PPV and NPV of MRS were 94. 4% (95% CI, 74. 2– 99), 80% (95% CI, 54. 8– 93), 96%, 85% and 92. 4%, respectively. Conclusion: The results of this study indicate an acceptable level of sensitivity, specificity and accuracy of MRS in the differential diagnosis of PCa and prostatitis.