 Good evening, respected judges and my colleagues. I'm Dr. Nidhi Rai, radiology resident of VMMC and Satyajan Hospital. And I'll be presenting before you my paper titled, RT has been labeled MRI for evaluating perfusion of brain tumors. I've done this under the guidance of Dr. Rupi Chambal, who is the associate professor and consultant at the Department of Radial Diagnosis, Satyajan Hospital. There were no conflicts of interest and nothing to disclose. The aim of my study was to determine the vascularity of brain tumors by evaluating tumor blood flow using RT that's been labeling perfusion imaging. CNS tumors are an important cause of mortality and mobility. Tying the diagnosis and treatment is therefore a necessity in case of brain tumors. Conventional MRI combined with perfusion MRI imaging provides useful information for diagnosis and treatment of brain tumors. Now, the perfusion refers to the delivery of blood at the level of capillaries. And it is measured in units of ML per 100 grams per minute. Perfusion parameters give direct insight about the tumor vascularization and proliferation, which is essential in evaluation of brain tumors, where more aggressive lesions typically display greater vascularity. Traditional imaging in MR requires bolus injection of contrast material through large-bore intravenous cannulas for the evaluation of blood flow to the brain tumors. This is an invasive method, hence has a limited use. Arteral spin labeling perfusion imaging is an evolving magnetic resonance imaging technique that measures cerebral blood flow without the use of an intravascular contrast agent. This technique provides a noninvasive way to evaluate cerebral blood flow by magnetically labeling the arterial blood protons before it flows into the area of interest. In this technique, two images are required, a control image and a labeled image. A control image is an image in which the blood water magnetization has not been inverted, and labeled image is an image in which there is inversion of the blood water magnetization. The signal difference between these two images is calculated, which is directly proportional to the amount of magnetization inversion delivered to the area of interest. Arteral spin labeling offers the most significant advantage over traditional contrast perfusion techniques, as it does not require a gadolinium-based tracer, that is, it is noninvasive. Hence, favorable for patients with renal dysfunction, for pediatric population, and for those required repeated follow-up scans. Methodology. The study, my study was conducted, a study was conducted in the Department of Radio Diagnosis in collaboration with the Department of Neurosurgery and Department of Pathology, VMMC, and Subdijang Hospital. It was an observational cross-sectional study, and it was conducted over a period of 18 months. For sample size calculation, formula for correlation analysis was used, and sample size turned out to be 33 by calculation. However, we included a total of 46 patients, participants of suspected brain tumors, and that was based on clinical history and previous imaging investigations, out of which 35 participants turned out to be brain tumor patients that satisfied our inclusion criteria, which we'll discuss later. MRI acquisition was carried out in a single session on 3-Tesla MR imaging machine with a 32-channel phased area head-neck spine coil. All cases of brain tumors referred from the Department of Neurosurgery in our hospital, that is Subdijang Hospital, were included in our study. Exclusion criteria included patients with one or other contraindications for MRI, like the patients with metallic clips, pacemakers, or patients having claustrophobia, patients with any patients with known malignancy other than brain tumor, with secondary metastasis in the brain, and patients of brain tumor with previous surgical interventions. Written informed consent was taken from each patient that fulfilled the inclusion criteria, and clinical history was noted from each patient, and findings were recorded of pre-designed performer. Patients underwent pseudo-continuous articles been labelling perfusion imaging on 3-Tesla MRI machine. MRI sequences, ASL perfusion imaging study was performed with whole brain extending from vertex to the base of skull. Images were obtained using background suppressed 3D stacked spiral FAC sequence. After performing conventional MRI sequences, that is T1, T2, and FLARE, 3D ASL was performed by use of pseudo-continuous labelling period of 1,500 milliseconds with post-labelling delay time ranging from 15-25 milliseconds to 2,000 milliseconds, depending on the age of the patient. The labelling plane was selected at the level of PONS medulla junction to avoid the curvature of peterous part of ICA and to select the end portion of ascending ICA. Slice thickness was taken as 4mm with no inter-slice cap. The tumor in its greatest dimension was made to coincide with the imaging plane by referring to conventional MRI sequences that is T1, T2, and FLARE. Post-processing, the ASL-colored maps were acquired and ROIs were placed in axial plane in the region with maximum perfusion. Non-overlapping regions of ROIs of size more than or equal to 5mm of equal size were visually placed on all the tumors on the axial ASL. And then their absolute and relative values of maximum and mean tumor blood flow was measured within the tumor. Relative TBF values were measured by taking the ratio between TBF and the CBF values, that is tumor blood flow and the cerebral blood flow values. Then these patients were followed up and tumor tissue biopsy sample of operated patients was sent to the Department of Pathology for histopathological analysis. Their microvascularity of the brain tumors were evaluated. The tissue sections were immunostained using a monoclonal mouse antibody directed against the CD34 antigen, which identifies vascular endothelial cells. Microvessals within the tumors were counted in three hot spots at both 10x and 40x magnification. And the mean of the three values of the vessel count was considered to be the microvessel density. Results, as we said before, but included 46 participants and out of which 35 turned out to be patients of brain tumors that satisfied our inclusion criteria and that could be considered a part of study. Out of these 35 patients, there were 19 cases of gliomas, including pylocytic astrocytoma, pleomorphic xanthastrocytoma, oligodendroglioma, diffused astrocytoma, anaplastic astrocytoma, glioblastoma and giant cell glioblastoma. 19 were gliomas, 11 were meningiomas, two schwannomas, two cleniform angiomas, and one was hemangioblastoma. In our study, most of the patients presented with complaints of headache, weakness of one side of the body, seizures, and blurring of vision in some cases. Correlation was a correlation between the mean tumor blood flow and the vessel count at 10x and 40x magnification was calculated using Spearman correlation coefficient and both of which came out to be positively correlated with p value of less than 0.001. Then correlation between maximum tumor blood flow and the vessel count at both 10x and 40x magnification also came out to be positively correlated with p value of less than 0.001. Now, there was a strong positive correlation between vessel count and mean TBF. TBF at vessel count seen at 10x magnification and mean TBF, and this correlation was statistically significant like we saw in the graph. And also, there was a moderate positive correlation between vessel count at 40x magnification and mean TBF. A very strong positive correlation between max TBF and vessel count at 10x magnification was seen and this correlation was statistically significant. A strong positive correlation between maximum TBF and vessel count at 40x magnification was seen and this correlation was also statistically significant. These are a few of the representative cases. In the first figure, the first figure was that of a patient which was diagnosed with Hemanju Blastuma, which showed a cystic lesion with solid components seen at left CP angle and it showed a very high vascularity. On ASIL color map, it showed the mean TBF value of 402 milliliters per minute per 100 grams and maximum TBF value of 578.3 milliliters per minute per 100 grams with relative TBF mean of 14.9 and relative TBF max of 38.7. It showed the Hemanju Blastuma showed a very high vascularity, also high in comparison to the meningomas or other high grade glermas. In figure two was a case of meningoma seen in the left frontal region and it showed on ASIL color map, mean TBF was 368 milliliters per minute per 100 grams, max TBF was 386 milliliters per minute per 100 grams, RTBF mean was 6.5 and RTBF max was 52.9. The third case was a case of meningoma arising from atria of the left glateral ventricle. The on ASIL color map, mean TBF was found out to be 127 milliliters per minute per 100 grams, max TBF was 143 milliliters per minute per 100 grams and RTBF mean was 4 and RTBF max was 35. The figure four was a case of atrial meningoma seen in the right posterior fossa region. It showed a low vascularity compared to the other meningomas. It's mean TBF was calculated to be 11.6 milliliters per minute per 100 gram, which is very less compared to the other meningomas and max TBF was calculated to be 15 ml per minute per 100 grams, RTBF mean was 0.4 and RTBF max was 37.5. On 1734 IHC staining, we got the pictures similar to given in this slide. Figure one shows CD34 staining slide with high microvessel proliferation. We can see the stained vessel, brown colored stained vessel walls in the first figure. And figure two shows a low microvessel proliferation. Discussion. The mean age of mean TBF obtained from our study, mean range was found out to be 133 plus minus 91.6. Max TBF was 160 plus minus 116. RTBF mean was four plus minus 2.8 and RTBF max was 39 plus minus 10.4. We used Spearman correlation that is a nonparametric test to study correlation between TBF and microvessel density in brain tumors. And the correlation between mean TBF and microvascular density at both 10x and 40x and maximum TBF and microvascular density at again both 10x and 40x was found to be statistically significant. A strong positive correlation was seen between mean TBF and microvascular density at 10x magnification. Moderate positive correlation between mean TBF and microvascular density at 40x magnification. A very strong positive correlation between max TBF and MVD at 10x magnification. And a strong positive correlation was seen between max TBF and MVD at 40x magnification. These findings were found to be in agreement with few studies which were conducted by T. Noguchi et al, Koizumi S et al, Kikuchi et al and Kimura et et al, which also show a positive correlation between mean TBF and max TBF with MVD, which is also known as the percentage vessel count. In our study, we also measured relative TBF values which were normalized to the CBF values that is the cerebral brain flow values. The mean range of the values of mean CBF was 33 plus minus nine and maximum CBF was 40 plus minus 11.2. CBF values were taken by placing ROI at cortical gray matter. For this, Steven images were used. Gray matter was taken as reference in concordance with few studies like those of Weber, MA et al, and Jutukonda, MR et al, which have mentioned that ASL underestimates white matter perfusion, thus favoring gray matter as the reference. Correlation between RTBF mean and vessel count at 10X and 40X and RTBF max and vessel count at 10X and 40X, which was also found to be statistically significant in our study showing a positive correlation between RTBF mean and vessel count at 10X and 40X. Moderate positive correlation was seen between RTBF max and vessel count at 10X and 40X. These were my references. Thank you. Thank you so much.