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Left ventricular (LV) structure and function module

a) SCMR official document standardized acquisition guidelines – relevant extract

1. Scout imaging – transtransaxial, coronal, sagittal
2. Transaxial (8–10 mm) set of steady state free precession (SSFP) or fast spin echo images through the chest.
3. Scout to line up short axis images – cine acquisitions are preferable to single shot as long axis motion and inflow should be visualized
   a. Vertical long axis prescribed orthogonal to transaxial scouts aligned through the apex and center of the mitral valve
   b. Horizontal long axis aligned orthogonal to the vertical long axis, passing through the apex and center of the mitral valve
4. Steady state free precession short axis cine images, from the mitral valve plane through the apex. The basal most short axis slice should be located immediately on the myocardial side of the atrioventricular junction at enddiastole prescribed from the previously acquired long axis cines.
   a. Slice thickness 6–8 mm, with 2–4 mm interslice gaps to equal 10 mm.
   b. Temporal resolution ≤ 45 ms between phases
   c. Parallel imaging used as available
5. Steady state free precession long axis cine images
   a. The 4 chamber long axis is prescribed from the vertical long axis through the apex and center of the mitral and tricuspid valves. This can be cross-checked on basal short axis cines, using the costophrenic angle (margin) of the RV free wall.
   b. Vertical long axis, prescribed from the scout already acquired
   c. LV outflow tract (LVOT) long axis, passing through the apex, the center of the mitral valve and aligned with the center of LVOT to aortic valve, as seen on a basal short axis cine.
   d. Optional – a set of more than 3 rotational long axis views can be obtained.
6. Analysis
   a. All short axis images are evaluated with computer-aided analysis packages for planimetry of endocardial and epicardial borders at end-diastole and end-systole. More advanced software automatically adjusts for systolic atrioventricular ring descent.
   b. The inclusion or exclusion of papillary muscles in the LV mass should be the same as that used in normal reference ranges used for comparison.
   c. Care must be used at the 1 or 2 most basal slices. Due to systolic movement of the base towards the apex in normally contractile ventricles, the end-systolic phase will include only left atrium. This may not be the case in a severely dysfunctional LV. Either way, this slice at enddiastole will include LV mass and volume.

b) SCMR official document reporting recommendations – relevant extract

1. The reporting of right ventricular (RV) and left and right atrial chamber sizes and volumes are optional.  Reporting of left ventricular (LV) volumes is recommended when multi-slice cine short axes data are acquired from the mitral annulus to the cardiac apex.  When reported, SCMR suggests that right-sided chambers measurements and the angulation from which the diameters or dimensions are acquired should be reported.  For the left-sided cardiac chambers, the 3-chamber long axis view should be used for identifying LV dimensions.  The SCMR encourages quantitative measures reported on their forms; however, determination of normal, enlarged, small, or not reported may be substituted.
2. Although not required, the SCMR encourages the reporting of LV end diastolic wall thicknesses acquired in the 3-chamber view of the left ventricle at the mitral leaflet tips; it is suggested that the end diastolic thickness be acquired at the septum and inferior lateral or  posterior wall.  
3. When assessing the right ventricle, the free wall end diastolic thickness (in the middle atrium portion of the wall) may be reported.
4. For those studies targeting the heart, the SCMR recommends the reporting of LV ejection fraction, and regional wall motion abnormalities.  The method of acquisition should be reported, including:
      â–ª Visual estimation
      â–ª Area-length formula
      â–ª Multi-slice disk summation technique
Values should be reported as absolute values and indexed for body surface area. Measurements derived from these values (i.e., cardiac output) should be expressed as absolute as well as indexed values and the reference heart rates used for these calculations should be provided in the report.
Regional wall motion should be described as qualitatively or quantitatively assessed in the 17–segment model adopted by the ACC/AHA guidelines 2 for noninvasive testing (Figure 1).  Qualitative assessments should follow the following nomenclature in which each segment is identified as: 
_ hyperkinetic
_ normokinetic
_ hypokinetic
_ akinetic
_ dyskinetic
_ tardykinetic
_ paradoxical 
_ not assessed
If the respective site seeks to report quantitative measures, such as thickening or strain, these should be performed and reported according to previously published techniques.

c) Expert opinion – ‘How we do’

"How I Do" a CMR Volume Study ( James Moon, The Heart Hospital, London)

d) An xls spreadsheet for reference ranges. (Upload, save as template, enter data, cut and paste table into report) Normal and indexed CMR ssfp reference ranges by age (note: password is 'CMR' to change spreadsheet)
**NEW: June 2011: An LV and RV normal reference range calculator with graphs. Note: save as template and reuse...

e) Relevant Online Talks

Free talks

How to set up your study and plan your slice positions
By Allison G Hays - John Hopkins University
Recorded at SCMR 2010

Evaluation of Volumes, Function, Mass and Post Processing
By Jerome Garot - Massy, France
Recorded at EuroCMR 2009 Athens

Anatomy/Function
By Ana Almeida
Recorded at EuroCMR 2008

Members only talks - general

Measure regional and global LV function
By Rob van der Geest - Leiden
Recorded at SCMR2008 Physician Pre-Conference Section 2: How to …

Members only talks - cutting edge

Diastolic Function - The Ultimate Pump
By Sandor Kovacs - Washington University
Recorded at SCMR 2008: Technicians Workshop

f) Reference ranges (this list not exhaustive)

Maceira AM, Prasad SK, Khan M, Pennell DJ. Normalized left ventricular systolic and diastolic function by steady state free precession cardiovascular magnetic resonance.  J Cardiovasc Magn Reson. 2006;8(3):417-26.

Hudsmith LE, Petersen SE, Francis JM, Robson MD, Neubauer S. Normal human left and right ventricular and left atrial dimensions using steady state free precession magnetic resonance imaging. J Cardiovasc Magn Reson. 2005;7(5):775-82