MR in hypertension

Abstract

Hypertension is a common systemic disorder affecting the cardiovascular system and kidneys with important morbidity and mortality. However, hypertension is often thought of by radiologists as an “invisible” disease. The aim of this article is to first review hypertension first in terms of its diagnosis, epidemiology and clinical importance. Second, those causes of secondary hypertension that may be diagnosed with MRI techniques are described along with the effects of hypertension on the cardiovascular system and kidneys that are demonstrable with MRI with particular emphasis on renovascular disease. Lastly the use of integrated MRI protocols to evaluate the hypertensive patient and areas for future research are considered. J. Magn. Reson. Imaging 2011;. © 2011 Wiley Periodicals, Inc.

Comprehensive First‐Line Magnetic Resonance Imaging in Hypertension: Experience From a Single‐Center Tertiary Referral Clinic

“…In this study, five of 15 myocardial infarctions seen on MRI were unexpected diagnoses and resulted in initiation of secondary prevention medication. Accurate evaluation of LVM, morphology, and fibrosis also helps to differentiate between hypertensive heart disease and hypertrophic cardiomyopathy, which makes MRI an important tool for assessing patients with significant LVH and concurrent hypertension . The use of gadolinium as an MRI contrast agent carries a risk of nephrogenic systemic fibrosis (NSF), quantified as an incidence of 0.02% in one retrospective, multicenter study of 83,121 patients .…”

“…Our MRI protocol includes a simple single breath‐hold axial T1‐weighted imaging stack (5‐mm slice thickness) through the abdomen to screen for “resolvable” adrenal lesions, and therefore small abnormalities may be missed. High‐resolution adrenal CT or MRI, beyond our study protocol, is therefore required in patients with positive biochemistry to identify microadenomas and differentiate between pheochromocytomas and adenomas presenting as Conn or Cushing syndrome . Pituitary lesions can be seen on standard MRI; however, a dedicated contrast‐enhanced MRI scan is also required to localize pituitary microadenomas …”

“…MRI is a safe and effective imaging modality for screening patients with high BP for asymptomatic TOD and secondary causes of hypertension. It provides high diagnostic specificity and sensitivity for identifying LVH and RAS, and while CMR is not one of the primary imaging modalities recommended in clinical hypertension guidelines, it is the current gold standard for the noninvasive assessment of LV volumes, mass, and function . We acknowledge that MRI remains a relatively expensive investigation and is not routinely available in the community; however, diagnostic information from multiple organ systems can be obtained from a 1‐hour scanning session, and this increased efficiency will be of benefit to patients.…”

“…For example, CMR is widely regarded as the gold‐standard noninvasive imaging modality for the clinical assessment of left ventricular (LV) mass (LVM) and LV hypertrophy (LVH) . In addition, MRI techniques can be used to image the vasculature (including the renal arteries), renal parenchyma and adrenal glands with high accuracy . MRI could improve diagnostic efficiency in these patients as it is a highly sensitive imaging modality and would avoid the need for multiple appointments for echocardiography, renal ultrasound, and, potentially, vascular computed tomography (CT) angiography.…”

Will advances in functional renal magnetic resonance imaging translate to the nephrology clinic?

“…Hypertension is the second leading cause of renal failure in the Western world 52 and MRI may disclose both causes of raised blood pressure and the effects of it 37 . The commonest cause of secondary hypertension is renal parenchymal disease (which may be multifactorial) while arteriosclerotic or fibromuscular renovascular disease and obstructive uropathy are also important causes.…”