HOW I DO Arrhythmogenic Right Ventricular Cardiomyopathy Dysplasia

HOW I DO… Arrhythmogenic Right Ventricular Cardiomyopathy/ Dysplasia David A. Bluemke, MD, Ph. D, Nadine Kawel, MD University of Wisconsin School of Medicine and Public Health, Madison Wisconsin USA Department of Radiology, Kantonsspital Graubuenden, Chur, Switzerland

Background and Rationale • Arrhythmogenic right ventricular cardiomyopathy/ dysplasia (ARVC/D) is a rare condition, usually presenting in individuals age 20 -40 years old. • Most forms of ARVC/D present with right ventricular predominant disease. • As the disease progresses, biventricular disease is common. • Less frequently, left predominant ARVC/D occurs.

Background and Rationale • The CMR protocol is designed to optimize imaging of the right heart. • The primary characteristics that need to be evaluated include: 1. Right ventricle (RV) size and global/ regional wall motion 2. Evidence of late gadolinium enhancement (LGE) – particularly for exclusion of other arrhythmogenic cardiomyopathies. About 60% of ARVC/D patients have LGE – especially in advanced disease. 3. Evidence of RV fat. This is present only in advanced ARVC/D.

Protocol Major components of the ARVC/D protocol include the following: 1. Black blood T 1 images. 2. Standard cine imaging of the heart. 3. Late gadolinium enhancement (LGE) imaging. Cine and LGE images are relatively standard similar to other CMR protocols. However, additional imaging planes may be useful in ARVC/D evaluation. These are explained on subsequent slides.

ARVD/C – Protocol Summary 1. Axial & short axis black blood T 1 images • 5 mm slice thickness, ETL 24 -28 • to avoid wrap-around, use anterior coils only • 10 -12 slices axial, 5 slices short axis over the LV only. 2. Same as (1), but axial only, with fat suppression 3. SSFP Cine: axial and short axis, LV/ RV long axis cine • 10 -12 short axis cine images, 8 axial images, 4 chamber cine 4. Late gadolinium enhancement images • 5 short axis images, 6 -8 axial images Note: since the protocol is long, the minimum # of slices in each plane is given.

ARVD/C – Patient Preparation 1. Beta blocker administration before the examination is important to control arrhythmia 2. The examination should be terminated early if severe arrhythmia reduces examination quality.

Protocol – Step 1: Black Blood T 1 Images Imaging plane: Sequence: Slice thickness Slice gap Matrix TR: TE: FOV: ETL: Number of slices Other: Axial double inversion recovery FSE/ TSE 5 mm slice thickness 3 mm gap 256 x 192 matrix minimum 1 R-R interval minimum full echo 24 -28 cm 12 -24; parallel imaging may be useful if phase wrap can be avoided from the diaphragm to aortic outflow tract, typically 10 slices. Saturation band on the anterior chest wall and posterior chest wall 1 slice per breath-hold

Protocol – Step 1: Black Blood T 1 Images Example images: Note the anterior saturation band. This reduces artifacts and improves uniformity of the image signal.

Protocol – Step 1: Black Blood T 1 Images Imaging plane: Sequence: Slice thickness Slice gap Matrix TR: TE: FOV: ETL: if Number of slices tract, Other: wall Short axis double inversion recovery FSE/ TSE 5 mm slice thickness 5 mm gap 256 x 192 matrix minimum 1 R-R interval minimum full echo 24 -28 cm 12 -24; parallel imaging may be useful phase wrap can be avoided from the diaphragm to aortic outflow typically 5 -6 slices. Saturation band on the anterior chest and posterior chest wall 1 slice per breath-hold

Protocol – Step 1: Black Blood T 1 Images Example image: Note: complete coverage of the apex and base of the LV is not necessary. In the case shown, there is extensive fat infiltration of the RV and LV

Protocol – Step 2: Black Blood T 1 Images Next step: repeat step 1 with fat suppression, use the same slice locations. Axial plane only is sufficient.

Protocol – Black Blood Key Points 1. Do not use prone imaging. This is uncomfortable for the patient, in an otherwise long protocol. 2. Do not use single shot TSE/ FSE techniques. These result in severe blurring of contrast between soft tissues. Zero-filled interpolation should be used if available, to obtain a 512 x 512 reconstruction matrix. 3. If severe arrythmias are present, and the examination ‘must’ be completed: the cine long axis images are more important, and a moderately complete examination can be obtained without the black blood images

Protocol – Step 3: Short and Long Axis Cine Images Preparation: Depending on your institutional protocol, you can administer gadolinium contrast (0. 15 -0. 20 mmol/kg) prior to obtaining cine images. This saves some time for the LGE image acquisition, avoiding further delays. Cine images: perform cine images in the following planes: a) Axial (same slice locations as the black blood images) b) Short axis (complete coverage, used for quantification of RV and LV function). c) Long axis (standard imaging planes: 2, 3, and 4 chamber views). Vertical long axis views of the right ventricle may be included.

Protocol – Step 3: Short and Long Axis Cine Images Imaging plane: Axial, short axis and long axis SSFP Sequence: SSFP Slice thickness 6 mm slice thickness Slice gap 2 mm gap Matrix 256 x 192 matrix minimum TR: minimum TE: minimum Flip angle: 45 -70 degrees FOV: 36 -40 cm Temporal resolution: approximately 40 msec; reconstruct 30 -40 phases

Protocol – Step 3: Short and Long Axis Cine Images Short axis cine Long axis cine

Protocol – Step 3: Short and Long Axis Cine Images 4 chamber view LV outflow tract 2 chamber view RV long axis

Protocol – Step 4: LGE Short and Long Axis Imaging plane: Sequence: Slice thickness Slice gap Matrix IR: FOV: Other: Axial, and short axis IR-prepared fast/ turbo gradient echo 6 mm slice thickness 2 mm gap 256 x 192 matrix minimum adjusted to suppress normal myocardium 36 -40 cm phase sensitive reconstruction

Protocol – Step 4: LGE Short and Long Axis 4 images from short axis LGE 4 images from axial LGE

Interpretation: ARVC/D Task Force Criteria Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy/ Dysplasia Proposed Modification of the Task Force Criteria

Interpretation: ARVC/D Task Force Criteria* MRI: regional RV akinesia or dyssynchrony, and: Major criteria Minor criteria • RV EDV ≥ 110 ml/m 2 (men) • RV EDV ≥ 100 ml/m 2 (men) ≥ 100 ml/m 2 ≥ 90 ml/m 2 (women) • or RV EF ≤ 40% • or RV EF >40 ≤ 45% *note: RV/ LV fat is not a Task Force criteria, as this was not reliable across sites; in addition, fat is a late sign. However, fat presence, when detected, can add specificity for the diagnosis of ARVC.

Interpretation: ARVC/D Task Force Criteria All criteria I. Global or regional dysfunction and structural alterations II. Tissue characterization of wall III. Repolarization abnormalities IV. Depolarization/ conduction abnormalities V. Arrhythmias VI. Family history

Interpretation: ARVC/D Task Force Criteria Major abnormalities: 2 points; minor: 1 point ü Definite ARVC: ≥ 4 points ü Borderline: 3 points ü Possible: 2 points

Interpretation: ARVC/D Task Force Criteria Tissue: major, <60% residual myocytes + fibrous replacement, +/- fatty replacement Conduction: inverted T-waves, epsilon waves (major) Arrhythmia: NSVT or VT with LBBB Family Hx: familial disease 1 st degree relative or known pathogenic mutation

Interpretation: ARVC/D Task Force Criteria If there is a proven 1 st degree relative, then familial ARVD needs any one minor criteria: • T wave inversions V 1 -V 4 (over age 14 yrs) • Late potentials by SAEG • VT of LBBB morphology or >200 PVC/ 24 hrs • Imaging: Mild global dilatation or reduction in RV ejection fraction with normal LV or mild segmental dilatation of the RV or regional RV hypokinesis

Interpretation: ARVC/D, Case 1 • RV ejection fraction 35%, abnormal. • RV EDV 95 ml/m 2 within normal limits • Dyskinesia of the anterior wall of the right ventricle • Interpretation: Major CMR criteria for ARVC/D due to low RV ejection fraction and regional wall motion abnormality

Interpretation: ARVC/D, Case 2 • Axial T 1 images (left) and T 1 fat suppressed images show RV fat (arrows). LV fat is also present, in the epicardial mid/ apical region (large arrow)

Interpretation: ARVC/D, Case 2 • RV dilatation is present (volume 115 ml/m 2) in addition to low ejection fraction (40%) • Regional dyskinesia is present in the subtricuspid region • LV epicardial fat is apparent on the cine

Interpretation: ARVC/D, Case 2 • LGE images show enhancement in the anterior RV wall, as well as in the septum and epicardial LV wall. • Cine images give a major criteria for ARVC/D. • T 1/ fat images and LGE images further strengthen the interpretation.

Final Thoughts We intend for this guide to be a living document and plan to add new content over time. Comments, questions, and requests can be directed to: hq@scmr. org