<prompt> Which of the following is the most specific screening test for renovascular hypeension:Magnetic Resonance Angiography MRASpiral Computed Tomographic Angiography CT AngiographyCaptopril induced Radionucleotide Scan Captopril RenogramDuplex Doppler Ultrasonography  <response>: Answer is A Magnetic Resonance Angiography MRA Magnetic Resonance Angiography MRA has now emerged as the most sensitive and specific screening test for Renovascular hypeension. Note: Harrison 16h edition old mentions Spiral CT scan as the most sensitive and specific screening test for Renovascular Hypeension, however most recent textbooks now prefer MRA as the screening test of choice with similar or even better sensitivity and specificity than spiral CT Angiography. Screening Test Test Sensitivity Specificity Magnetic resonance angiography MRA 100 96 Spiral computerized tomography 98 94 Captopril renogram 70-93 95 Duplex Doppler ultrasonography 69-96 86-90 IVP --75 --85 Renovascular Hypeension Test Sensitivity Specificity Conventional Renal Angiography 99 99 