MR formulas Exam Questions With Correct Answers.

MR formulas Exam Questions With Correct Answers. Calculate the scan time for a 3D gradient echo sequence with the following parameters: FOV 20cm, TR 24, TE 10, 224 x 256 matrix, 1 NEX, 3.5 mm slice thickness, 40 slices - answer3 min 35 sec 3D sequence scan time : TR x Phase Matrix x NSA/NEX x # Slices = 3D Scan Time, ÷ 1000 to convert to seconds. 24 x 224 x 1 x 40 ÷ 1000 = 215 seconds (3 min 35sec) Calculate the scan time for a spin echo sequence with the following parameters: TR 500, TE 24, 224 x 256 matrix, 3 NEX, 4 mm slice thickness. - answer5 min 36 sec TR x Phase Matrix x NSA/NEX = Scan Time in a Spin Echo sequence, Divide by 1000 to convert ms (milliseconds) into seconds. 500 x 224 x 3 ÷ 1000 = 336 seconds. Calculate the voxel volume for a fast spin echo sequence with the following parameters: FOV 20cm, TR 3000, TE 120, 224 x 256 matrix, 3 NEX, 5 mm slice thickness, 12 ETL - answerFOV ÷ phase matrix = phase dimension pixelFOV ÷ frequency matrix = frequency pixelMultiply phase pixel size x frequency pixel size = Pixel area (answer squared2)Pixel area x slice thickness = Voxel volume (answer cubic3) Convert 20cm to 200 mm before calculating. 200 ÷ 224 = 0.89mm (phase dimension) EXAM STUDY MATERIALS July 29, 2024 12:59 PM 200 ÷ 256 = 0.78mm (frequency dimension) 0.89 x 0.78 = 0.69mm2 (pixel area) 0.69 x 5mm(slice thickness) = 3.45mm3 Calculate the pixel size for a fast spin echo sequence with the following parameters: FOV 30cm, TR 600, TE 10, 320 x 320 matrix, 4 NEX, 3 mm slice thickness, 3 ETL - answer0.94 mm x 0.94 mm Convert Convert 30cm to 300 mm before calculating. 300 ÷ 320 = 0.94mm (phase dimension) 300 ÷ 320 = 0.94mm (frequency dimension) Calculate the pixel size for a fast spin echo sequence with the following parameters: FOV 28cm, TR 2000, TE 30, 256 x 320 matrix, 2 NEX, 4 mm slice thickness, 8 ETL - answer1.09 mm x 0.88 mm Convert 28cm to 280 mm before calculating. 280 ÷ 256 = 1.09mm (phase dimension) 280 ÷ 320 = 0.88mm (frequency dimension) Calculate the scan time for a spin echo sequence with the following parameters: TR 350, TE 10, 256 x 256 matrix, 2 NEX, 5 mm slice thickness - answer2 min 59 sec TR x Phase Matrix x NSA/NEX = Scan Time in a Spin Echo sequence, Divide by 1000 to convert ms (milliseconds) into seconds. 350 x 256 x 2 ÷ 1000 = 179 second