الفهرس 
Anatomy of the Kidney & Renal vesselsOnly 14 pages are availabe for public view
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Abstract
Renovascular hypertension (RVHT) refers to hypertension caused by renal ischemia. It is defined as the presence of systemic hypertension due to a stenotic or obstructive lesion within the renal artery.
American College of Radiology (ACR) has defined RAS in adults as: Anatomic narrowing of the renal artery lumen diameter by 50% or greater. RVHT is the most common type of secondary hypertension with estimated prevalence between 0.5% -5% of the general hypertensive patients. There are varied causes of reduced renal perfusion with resultant RVHT, the most common being renal artery stenosis (RAS) secondary to either atherosclerotic disease (90%) or fibromuscular dysplasia (FMD) (10%).Recently, a non-invasive (CTA) and (MRA) imaging techniques are routinely used to visualize the renal arteries with IV of CM. Both of them also are contraindicated in advanced chronic kidney disease (CKD).
• Objective: To illustrate the usefulness of MDCT renal angiography for diagnosis and evaluation of RVHT.
• Conclusion: The benefits of MDCT angiography are substantial, including high spatial and temporal resolution, widespread availability, implantable device compatibility, and easy technical reproducibility.
MDCT angiography (MDCTA) is reliable modality in the detection of RAS with sensitivity values close up to 100%. MDCTA is more accurate in diagnosing proximal lesions and can also be used to assess patency & follow up of stent grafts.
Advantages compared to DSA include: less invasiveness, faster acquisitions, and multiplanar 3-D imaging. While the disadvantages of both techniques are ionizing radiation & use of nephrotoxic CM.
Careful selection of CT scanning protocols is needed to keep the radiation exposure ‘As Low As Reasonably Achievable’ (ALARA). ALARA principle emphasizes the need to perform justifiable CT scans with the minimum radiation dose necessary to meet clinical and diagnostic objectives.