Rest imaging also can provide valuable therapeutic guidance and prognostic information in patients without symptoms or signs of ventricular dysfunction or changing clinical status, especially in those with evidence of other forms of heart disease (eg, hypertensive, valvular). For example, echocardiography can identify LV or left atrial dilation; identify aortic stenosis (a potential non-CAD mechanism for angina-like chest pain); measure pulmo- nary artery pressure; quantify mitral regurgitation; identify a LV aneurysm; identify a LV thrombus, which increases the risk of death262; and measure LV mass and the ratio of wall thickness to chamber radius all of which predict cardiac events and mortality.20,117,263 267 Although nuclear imaging accurately measures EF, it does not provide additional information on valvular or pericardial disease and requires exposure to ionizing radiation.21,268 Although CMR is applied less widely, it also accurately measures LV performance and provides insight into myocar- dial and valvular structures.269 Use of delayed hyperenhance- ment techniques can identify otherwise undetected scarred as well as viable myocardium. Cardiac CT also provides high- resolution detection of cardiac structures and EF. Neverthe- less, all 3 tests generally are more expensive than a resting echocardiogram. Although the amount of ionizing radiation required in cardiac CT and nuclear MPI has been lowered over the years and will continue to reduce, the use of these tests for risk assessment is discouraged in patients with low pretest probability of CAD and in young patients. 3.2.2. Stress Testing and Advanced Imaging in Patients With Known SIHD Who Require Noninvasive Testing for Risk Assessment: Recommendations See Table 12 for a summary of recommendations from this section. 3.2.2.1. Risk Assessment in Patients Able to Exercise Class I 1. 