Fani Susanto: Diffrences of T2 Weighted Turbo… DIFFERENCES OF T2 WEIGHTED TURBO SPIN ECHO (TSE) MRI OF BRAIN AXIAL SLICES BETWEEN USE SENSITIVIY ENCODING (SENSE) WITH NO SENSE : EVALUATION OF SIGNAL TO NOISE RATIO (SNR) AND SCAN TIME Fani Susanto 1 , A. Gunawan Santoso 2 , Bagus Abimanyu 3 1 Poltekkes Kemenkes Semarang 2 Specialist Radiology Kariadi Hospital Semarang 3 Poltekkes Kemenkes Semarang e-mail: fanisusanto28@gmail.com ABSTRACT Backgroud: MRI examination of brain often find patients who were less cooperative, thus requiring rapid acquisition techniques. Parallel imaging technique sensitivity encoding (SENSE) utilizing the spatial information RF coil phased array to reduce the acquisition time by reducing the number of sampling lines K space therefore produce quality and good spatial resolution, but its has the limitations, namely the reduction of signal to noise ratio (SNR). SENSE was used along with pulse sequence one of turbo spin echo (TSE). The purpose of this research was to determine the differences in SNR and scan time on T2 weighted TSE MRI of brain axial slices between use SENSE with no SENSE. Methods: This research was a quantitative study with an experimental approach. Datas were collected from May to June 2016 in Radiology Unit Premier Bintaro Hospital by calculating the SNR value through software for the region of interest (ROI) and calculate the scan time through the scan timer on the workstation monitor. Data was analyzed by statistical tests with SPSS 16 software using paired T-test and descriptive. Results: From the statistical test result known that the SNR on T2 TSE between use SENSE with no SENSE the p-value 0,000 (p <0,05). This was because the encoding between the two images are different, the image of the T2 TSE without SENSE contained use of pulses in 180 0 approached TE effectively so shallow gradients produce echo maximum, while the image of the T2 TSE using SENSE there was a reduction in line phase encoding in the K space and their g-factor causing reduced SNR. From the analysis descriptively known that the scan time on T2 TSE between use SENSE with no SENSE by reducing scan time for 1 minute 24 seconds (49,01%). This was because the acquisition techniques are different between the two images, the image without SENSE T2 TSE contained ETL in the filling K space, while the T2 TSE images using SENSE R-factors are causing sampling did not fill all the K space so that the scanning time were reduced. Conclusion: There is a difference in SNR and scan time of T2 weighted TSE MRI of brain axial slices between use SENSE with no SENSE. Keywords : SENSE, SNR, Scan Time, T2 TSE, MRI Brain Axial INTRODUCTION Currently of magnetic resonance imaging (MRI) examination was a routine check at a large hospital. In principle, almost all organs can be examined with MRI. Ninty percents of MRI examinations performed on organs of the head and spine while the remaining 10% for the examination of other organs (Rasad, 2011). At the MRI of head examination, pulse sequences used one of them were turbo spin echo (TSE) T2 weighted (Westbrook, 2014). Pulse sequence was a series of events that includes a pulse radio frequency (RF), the activation gradient and signal collection undertaken to produce an MRI image. One commonly used pulse sequences are sequences TSE. TSE is a spin echo sequence with 180 0 refocus multiple radio frequency (RF) pulse after pulse 90 0 to produce echo row (Bitar et al, 2006). According Westbrook (2014), TSE sequences used for T2 weighted images because the scan time value obtained becomes short and also the use of sequences TSE will increase the value of the signal to noise ratio (SNR). Signal to noise ratio (SNR) and scan time were the two factors that determine the quality of the MRI image. SNR was a comparison value between the magnitude of the signal amplitude to amplitude noise. While the scan time is the time to complete the data acquisition. Values SNR and scanning time greatly affect the quality of the resulting image. SNR value greatly depends on the signals obtained from the organ, the higher the value of the existing signal at the organ SNR values will also be higher. While the value of scan time is very important to note because scanning a long time causing the possibility of patient movement during the acquisition that would affect the quality of the image will be generated (Westbrook et al, 2011). MRI examination of the head, especially the brain, axial slices were the "gold standard" for MRI examination of brain can show organ due clearer than the other slices (Liney, 2006). MRI of brain, often encounter patients who feel uncomfortable due to the length of the examination, thus causing the resulting image becomes less optimal and reduce diagnostic information. One way to reduce the scan time is to use a parallel acquisition technique or the parallel imaging technique. One of parallel imaging technique commonly used was sensitivity encoding or SENSE. SENSE was one of the parallel imaging technique which uses image formed by the phased array coil. SENSE reconstruction can accelerate the charging K space, causing a reduction in scan time (Dale et al, 2015). SENSE image reconstruction produces image quality in terms of contrast and spatial resolution is the same as the standard image reconstruction and takes only half the time required, but can reduce the value of the signal on the image anatomy. SNR reduction in reconstruction SENSE affected by the reduction factor (R) or the number of elements in the phased array coil is used (Glockner et al, 2005). Parallel imaging technique utilizes multiple elements in phased array receiver coil by reducing the encoding phase line on K-space