‘ ‘ How I do’ CMR in How I do’ CMR in HCM HCM Dr Sanjay Prasad, Royal Brompton Dr Sanjay Prasad, Royal Brompton Hospital Hospital London, UK. For SCMR August 2006 London, UK. For SCMR August 2006 This presentation is posted for members of scmr as This presentation is posted for members of scmr as an educational guide – it represents the views and an educational guide – it represents the views and practices of the author, and not necessarily those of practices of the author, and not necessarily those of SCMR. SCMR. [email protected]
Transcript
‘‘How I do’ CMR in How I do’ CMR in HCMHCM
Dr Sanjay Prasad, Royal Brompton HospitalDr Sanjay Prasad, Royal Brompton Hospital
London, UK. For SCMR August 2006London, UK. For SCMR August 2006
This presentation is posted for members of This presentation is posted for members of scmr as an educational guide – it represents scmr as an educational guide – it represents
the views and practices of the author, and not the views and practices of the author, and not necessarily those of SCMR. necessarily those of SCMR.
Characterized by myocyte disarray, Characterized by myocyte disarray, hypertrophy, and interstitial fibrosishypertrophy, and interstitial fibrosis
90% of pts have familial disease90% of pts have familial disease 10% 10% de novode novo mutations mutations Increased risk of SCDIncreased risk of SCD Adult prevalence 1:500 (Autosomal Adult prevalence 1:500 (Autosomal
Unexplained hypertrophyUnexplained hypertrophy Measured wall thickness exceeds 2SD for Measured wall thickness exceeds 2SD for
gender-,age-, and BSA-matched gender-,age-, and BSA-matched populationspopulations
≥ ≥ 1.5cm in absence of a recognized cause1.5cm in absence of a recognized cause There may be associated systolic anterior There may be associated systolic anterior
motion of the mitral valve leaflets and motion of the mitral valve leaflets and outflow tract obstructionoutflow tract obstruction
Multiple causative mutations in at least Multiple causative mutations in at least 10 different sarcomeric proteins10 different sarcomeric proteins
Variable phenotype and clinical outcomeVariable phenotype and clinical outcome
In addition to In addition to asymmetric asymmetric hypertrophy, there hypertrophy, there is often extensive is often extensive fibrosisfibrosis
‘How I do’ : CMR in HCM
HCM: SAM + LVOTOHCM: SAM + LVOTO
‘How I do’ : CMR in HCM
CMR Evaluation of HCMCMR Evaluation of HCM The first important aspect is determining LV and RV The first important aspect is determining LV and RV
volumes, ejection fractions, maximal wall thickness and volumes, ejection fractions, maximal wall thickness and massmass
We recommend the modified Simpson’s method rather We recommend the modified Simpson’s method rather than biplanar assessment since it makes no assumptions than biplanar assessment since it makes no assumptions on cardiac morphology and is both more accurate and on cardiac morphology and is both more accurate and reproducible.reproducible.
After piloting the 4ch and VLA views, retrospectively After piloting the 4ch and VLA views, retrospectively gated gradient echo cine slices are taken from the base gated gradient echo cine slices are taken from the base to apexto apex
Typically 7mm slices with a 3mm gap.Typically 7mm slices with a 3mm gap.
Usually myocardial coverage is achieved in 9-10 slicesUsually myocardial coverage is achieved in 9-10 slices
‘How I do’ : CMR in HCM
CMR QuantificationCMR Quantification
See the presentation ‘how I do’ LV volumes
Downloadable from www.scmr.org
‘How I do’ : CMR in HCM
HCM: Cine ImagingHCM: Cine Imaging
The key questions to address are: -The key questions to address are: -
1.1. Presence, distribution, and severity of Presence, distribution, and severity of
LVH and RVH. LV/RV mass and wall LVH and RVH. LV/RV mass and wall
thicknessthickness
2.2. Extent of septal involvement Extent of septal involvement
3.3. Distribution of hypertrophy in the variant Distribution of hypertrophy in the variant
forms of hypertrophic cardiomyopathyforms of hypertrophic cardiomyopathy
‘How I do’ : CMR in HCM
Functional AssessmentFunctional Assessment
Cine images are then acquired to Cine images are then acquired to determine if there is SAM and LVOTO.determine if there is SAM and LVOTO.
SSFP images with retrospective gating SSFP images with retrospective gating recommendedrecommended
‘How I do’ : CMR in HCM
HCM: LVOTO HCM: LVOTO AssessmentAssessment
In-plane followed by through plane In-plane followed by through plane breath-hold flow mapping is performed to breath-hold flow mapping is performed to look at the peak velocity at the outflow look at the peak velocity at the outflow tract (red-bar) and at the level of the tract (red-bar) and at the level of the aortic valve.aortic valve.
‘How I do’ : CMR in HCM
Assessment of FibrosisAssessment of Fibrosis
The presence of replacement fibrosis can The presence of replacement fibrosis can be detected using the inversion recovery be detected using the inversion recovery late enhancement technique following late enhancement technique following gadolinium-DTPA administration.gadolinium-DTPA administration.
After all, fibrosis is the main component of After all, fibrosis is the main component of chronic MI which is visible with the late chronic MI which is visible with the late enhancement techniqueenhancement technique
‘How I do’ : CMR in HCM
Gd infarct imaging
Fibrosis imaging in HCMFibrosis imaging in HCM
HCM fibrosis imaging?
‘How I do’ : CMR in HCM
HCM – a wide variety of scarHCM – a wide variety of scar
2 patients. For the lower patient, scar is present and invisible without Gd-DTPA. Many patients have no detectable scar
‘How I do’ : CMR in HCM
Fibrosis -not like IHD
Picro sirius red stains collagen red.
In-vivo vs exvivo match
‘How I do’ : CMR in HCM
Detection of Fibrosis: Inversion Detection of Fibrosis: Inversion Recovery SequenceRecovery Sequence
Dosage of Gd-DTPA: 0.1-0.2mmol/kgDosage of Gd-DTPA: 0.1-0.2mmol/kg At 0.1mmol/kg, images are usually At 0.1mmol/kg, images are usually
acquired after about 5 minutes with acquired after about 5 minutes with a TI starting at ~340ms (every other a TI starting at ~340ms (every other heart beat).heart beat).
At 0.2 mmol/kg, scans are acquired At 0.2 mmol/kg, scans are acquired after about 15 minutes with a TI after about 15 minutes with a TI starting at ~250ms.starting at ~250ms.
‘How I do’ : CMR in HCM
HCM: Detection of FibrosisHCM: Detection of Fibrosis
LGE is predominantly seen in a patchy LGE is predominantly seen in a patchy distribution and correlates with wall distribution and correlates with wall thickness.thickness.
Unlike in IHD, the subendocardium is not Unlike in IHD, the subendocardium is not necessarily affected.necessarily affected.
Unlike DCM, the distribution is typically Unlike DCM, the distribution is typically more diffuse and not specific to mid-wall more diffuse and not specific to mid-wall circumferential fibres.circumferential fibres.
‘How I do’ : CMR in HCM
Detection of Fibrosis: Inversion Detection of Fibrosis: Inversion Recovery SequenceRecovery Sequence
Tips to confirm fibrosis and not artefact:Tips to confirm fibrosis and not artefact:
1.1. Phase swap each slice Phase swap each slice
2.2. If mid-wall enhancement is seen, ensure TI is optimal and If mid-wall enhancement is seen, ensure TI is optimal and if need be, repeat the slice with a different TI if need be, repeat the slice with a different TI
3.3. Cross-cut through any areas of suspected mid-wall Cross-cut through any areas of suspected mid-wall enhancementenhancement
4.4. If subendocardial enhancement is seen, reconsider the If subendocardial enhancement is seen, reconsider the diagnosis or assess if this reflects ‘bystander’ coronary diagnosis or assess if this reflects ‘bystander’ coronary diseasedisease
5.5. It is common to see some fibrosis around the LVOT and at It is common to see some fibrosis around the LVOT and at the RV/LV septal insertion pointsthe RV/LV septal insertion points
‘How I do’ : CMR in HCM
Assessment of FibrosisAssessment of Fibrosis
late enhancement in the septum reflecting fibrosis
‘How I do’ : CMR in HCM
RV insertion point RV insertion point enhancementenhancement
2 spots of enhancement at RV insertion points2 spots of enhancement at RV insertion points The 3The 3rdrd point is artefact point is artefact
– – Present AP phase encoding, disappears head-foot. Present AP phase encoding, disappears head-foot. This is artefact ghosting across the image. This is artefact ghosting across the image.
‘How I do’ : CMR in HCM
Other techniques: perfusion
Perfusion defects in HCM – uncertain significance; here matching enhancement
Rest Perf Late Gd
‘How I do’ : CMR in HCM
SummarySummary
Evaluate function, volumes, maximal wall Evaluate function, volumes, maximal wall thickness, distribution of hypertrophy and thickness, distribution of hypertrophy and overall mass index.overall mass index.
Flow mapping to assess LVOTOFlow mapping to assess LVOTO Presence of fibrosis important using Presence of fibrosis important using
