Imaging Flashcards
Myocarditis - imaging
**Echo **
* wall thickening, reduced LVEF, strain (can track progress)
MRI - Lake Louise Criteria:
* Main:
Myocardial oedema (T2 T2W images)
Non ischaemic myocardial injury (abnormal T1, ECV or LGE)
- Supportive
Pericarditis (effusion or abniormal LGE, T1 or T2)
LV systolic dysfunction (RWMA or global)
Endomyocadial biopsy - Gold Standard
* If progressive symptoms despite treatment or specific diagnosis saught (Giant cell, Eosinophilic myocarditis)
Sarcoid - Imaging - Overview and Echo
- Complex inflammatory condition of unknown aetiology - can affect any organ of the body
- 20-25% of sarcoid patients have cardiac involvement on biopsy
Cardiac Sarcoid
* Asymptomatic
* AV conduction disease
* Heart Failure
* Ventricular arrhythmias (sudden death)
Cardiac complications are the leading cause of death in patients with sarcoid
Treatment
* Prolonged high dose steroids
Diagnosis
* Biopsy lacks sensitivity due to sampling bias (20-30%), as does serum ACE
* Advanced multimodality imaging required for diagnosis (echo/CMR/PET)
* Granulomas - inflammation and fibrosis. Anywhere in myocardium but particularly basal septum
Echo
* Early
Wall thickening (oedema), diastolic dysfunction
* Late
Wall thinning (scar), RWMA, systolic dysfunction
Poor sensitivity (25-65%)
Normal echo does not exclude
Sarcoid - Imaging - MRI and PET
Amyloid - Imaging - Echo
- Concentric hypertrophy, very commonly asymmetic (sigmoid septum or ISC)
- Atrial dilatation
- Speckled appearance of myocardium
- Preserved LVEF but reduced long axis function
- Restrictive filling pattern
- Pleural or pericardial effusions (more common in AL)
- Reduced LV strain - preserved in apical segments - bullseye appearance
Amyloid Imaging - MRI
- Subendocardial or transmural LGE
- Abnormal gadolinium kinetics (myocardium and blood pool black at the same time, subendocardial and epicardial LGE with dark middle “zebra striping”)
- ECV ≥40% - strongly suggestive but not diagnostic. T1 map can be used to track changes and is prognostic in ATTR and AL
Amyloid Imaging - 99m Tc-DPD (bone) Scintigraphy
- High sensitivity and specificity for ATTR
- Grade 1 - mild cardiac uptake, no attenuation of bone
- Grade 2 - moderate cardiac uptake, greater than bone
- Grade 3 - strong cardiac uptake, with little or no bone signal
If **grade 2 or 3 **and negative serum and urine immunofixation and serum free light chains –> diagnostic of ATTR amyloid
Include SPECT in protocol
If ATTR confirmed, ATTR genotyping (wild type vs variant)
HCM - Aetiology and Diagnosis
Diagnosis
* * In adults, LV wall thickness ≥15mm in 1 or more myocardial segments on echo/MRI/CT that is not solely explained by loading conditions
* In first degree relatives of patients with definitive HCM, ≥13mm
60% of cases, autosomal dominant transmission, caused by mutation in cardiac sarcomere proteins genes
Sarcomere genes
* Beta-myosin heavy chain MYH7
* **Myosin binding protein C **MYBPC3
These have higher rates of FHx, SCD, present earlier, more severe hypertrophy, increased fibrosis and poor prognosis
- Troponin T and I (TNNI3 and TNNT2)
- Tropomyosin alpha 1 (TPM1)
HCM - rare variants
Metabolic
* Anderson-Fabry’s Disease
* Gamma2 subunit of adenosine monophosphate receptor kinase (PRKAG2). 0.5-1% of HCM
* Danon Disease - lysosome-associated membrane protein 2 (LAMP2) 0.7-2.7% of HCM
Mitochondrial
* Respiratory chain protein complexes. MELAS, MERRF
Neuromuscular
* Friedrich’s ataxia
* Some other muscuolar dystophies and congenital skeletal myopathies (nemaline myopathy)
* FHL-1 mutations
* Occasionally desmin mutations (usually DCM or RCM)
Malformation Syndromes
* Usually MAPK mutations
* Noonan, LEOPARD, Costello
Infiltrative
* Amyloid
**Endocrine **
* Gestational DM (in the infant)
* Acromegaly
* Phaeochromocytome
Drugs
* Tetracylcines
* Hydroxychloroquine
HCM - ECG features of specific diagnoses
HCM - distinguishing from hypertensive heart disease
Favours HTN only
* Normal 12 lead ECG or isolated increased voltage witout repolarisation abnormality
* Regression of LVH after 6-12 months of tight BP control (SBP <130)
Favours HCM
* Family history of HCM
* RV hypertrophy
* LGE at RV insertion point or isolated to areas of maximum wall thickness
* Maximum wall thickness ≥15mm (caucasian), ≥20mm (black)
* Severe diastolic dysfunction
* Marked repolarisation abnormalities, conduction disease or Q waves
HCM - genetic testing
- Genetic testing should be done in patients who fulfil diagnostic criteria for HCM where it will facilitate family screening
- Patients with borderline HCM criteria - only genetically test after specialist team assessment
- Genetic testing should be done post mortem on pathologically confirmed HCM to allow for family screening
- Genetic testing (after counselling) in all first-degree adult relatives of patients with definite disease cuasing mutation
- If same genetic mutation in family member, clinical, ECG and echo follow up
- If the genetic mutation of proband not seen in family member - discharge family member
- If no definite gene mutation in proband, consider clinical assessment of relatives with ECG and echo every 2-5 years
HCM - syncope
- HCM diagnosis, syncope, high risk of sudden death –> ICD
- HCM diagnosis, syncope, low risk of sudden death –> ILR
- Syncope or symptoms with documented persistent or recurrent SVT or pre-excitation –> EPS +/- ablation
HCM - LVOTO
Diagnosed with LVOT gradient ≥30mmHg, clinically significant leading to treatment ≥50mmHg.
- General: Avoid dehydration, avoid alcohol, lose weight
- Drug Therapy: Non-vasodilating BB OR non-DHP CCB AND disopyramide (n.b. anticholinergic side effects)
- Invasive:
For patients with LVOT gradient ≥50mmHg, NYHA III-IV, and /or recurrent exertional syncope.
Ventricular septal myectomy (Morrow) +/- MVR
Alcohol septal ablation is an alernative. MDT decision
HCM - AF
- Warfarin for all, lifelong, unless prohibitive bleeding risk. Don’t use CHADS2VASc. If can’t use warfarin, DOAC
- Unstable - DCCV.
- Chest pain or heart failure - amiodarone or IV BB
- Stable - BB or non-DHP CCBs
- If LVOTO and normal EF, avoid digoxin
- Avoid flecainide and propafenone
- V Rate control - BB or non-DHP CCBs. Refractory - ablate AV node and pace (CRT-P in impaired LV function)
- V rhythm control - amiodarone, BB, CCBs. Refractory symptoms, no severe LA dilatation - consider ablation
- In HCM and sinus rhythm but LA ≥45mm, consider 48 hour holter every 6-12 months to detect AF
HCM - SCD risk factors
- Age (increased risk in the young)
- NSVT - ≥3 consecutive beats, ≥120bpm
- Maximum LV wall thickness. Severity and extent of LVH associated with SCD. Greatest risk in ≥30mm. Paradoxical reduced risk in thickness ≥35mm. Small number of patients. Use with caution.
- FHx SCD - ≥1 first degree relative <40 with sudden death with or without HCM diagnosis or SCD at any age in fisrst degree relative with HCM diagnosis
- Syncope - more predictive within 6 months of evaluation
- LA diameter
- Exercise BP response - <20mmHg increase from rest to peak exercise or fall >20mmHg from peak pressure
HCM - SCD prevention
- Advise against intense exercise or competitive sport
**Secondary prevention **
* VF/VT cardiac arrest or VT causing compromise or syncope and life expectancy > 1year - ICD
Primary Prevention
* Use HCM Risk-SCD calculator in those over 16 who don’t fit secondary prevention criteria
* Advise (after patient discussion etc) in 5 year risk ≥6%
* Consider in 5 year risk 4-6%
* *Consider in 5 year risk <4% and anoth risk factor
* Do not recommend if 5 year risk <4% and no other risk factor
HCM - ICD practicalities
- Set VF zone to 220 to avoid inappropriate shocks for AF with RVR
- Most patients only need single lead ICD. Exception is with LVOTO and to facilitate short AV delay pacing
- ICD with ongoing VT or appropriate shocks - BB or amiodarone
- ICD with inappropriate shocks for SVT - EPS +/- ablation
- No pacing indication - consider subcut ICD
HCM - follow up
- Clinical evaluation, ECG, echo - every 1-2 years or new symptoms
- 48 hour holter - New palpitations or every 6 months if sinus rhythm and LA diameter ≥45mm
- Consider CMR every 5 years
- Consider ETT or CPET when available every 2-3 years or annually if progressive symptoms
Congenital Imaging - Right Heart Dilatation
RA Volume Overload
* Forward loading - too much venous inflow
* Left to right shunting: ASD, TAPVD/PAPVD
* Reverse RA Loading: TR (Ebstein’s), LV to RA shunt (from VSD)
RV Volume Overload
* From RA: ASD, PAPVD
* From PA - pulmonary regurgitation (TofF)
Pressure Overload (acute only)
* Pulmonary HTN
* RVOTO
Congenital Imaging - Isolated LV dilatation - Causes
Extra-cardiac or intra-cardiac shunts
* PDA - L to R shunt
* AP window - L to R shunt
* VSD - L to R shunt
Early Cardiomyopathy
Abnormal Loading Conditions
* Anaemia
* Inflammation
* Renal impairment
* Iron deficiency
* Athlete (distinguish from DCM - improved LV strain and function on exercise, no LGE on MRI, normal diastolic function)
Imaging - Carcinoid
- Carcinoid tumours are rare neuroendocrine malignancies - often long asymptomatic phase until grow large or metastatsie
- Mostly in GI tract - often ileum
- Secrete various vasoactive substances: serotonin (5-HT), 5-hydroxytryptophan, histamine, bradykinin, tachkinin and prostaglandins
- Carcinoid syndrome generally when metastsise to liver. Flushing, secretory diarrhoea, bronchospasm, heart failure
- In patients with Carcinoid, NT-ProBNP the best biomarker for cardinoid heart disease
- Also, urinary 5-HIAA
- Thickened and retracted TV and PV leaflets - stenosis and regurgitation
- Rx - octreotide.
Arrhythmogenic Cardiomyopathy
DSP (desmophillin) - Causes LV predominant AVC
PKP2 - commonest in western patient. RV predominant AVC
If ICD needed - usually transvenous ICD so ATP can be given
Rx: Sotalol and mixiletine
MRI - physics and technique
Powerful magnetic field - 1.5T better workhorse than 3T, less artefact at lower magnet strength
Put patient in magnetic field, protons align with MF direction
Excite protons with radiofrequency pulses
When RF pulses stop, protons relax back to starting state and release energy - this can be measured - energy transformed into an image
T1 - longitudinal relaxation
T2 - transverse relaxation
Order:
Localised single shots - to identify heart in chest
Transverse stack through thorax to look at extracardiac anatomy
Cine imaging - long and short axis
LGE
Gadolinium - extracellular tracer - accumulates in areas of higher extracellular volume (ECV) - fibrosis, oedema, infiltration (amyloid).
Gadolinium potently decreases tissue T1. T1 sensitive sequences bring out change in gadolinium concentration. Focal areas of ECV expansion appear white on background of black myocardium
