MR Cardiac
HOW TO READ CARDIAC MRI:
Open Vitrea (use Wesley login)
Find patient- make sure you have Wichita RadPac and MRI picked in the search bar
At bottom highlight the SA stack and mitral valve flow at bottom of page and then open the app "CVMR".
Hover over the left square (SA stack) and then right click and pick "Q mass"
On the top options bar click the "Notepad looking icon" add in the patients height in cm (get patient height in inches from the rec sheet).
Now there should be a bunch of rows of squares arranged in rows and columns.
Go down the rows and exclude rows on the end that do not completely include both the LV and RV (typically this is both the first and the last row but can be more or less). To exclude a row- right click and "exclude"
Now pick a random row in the middle and highlight the whole row. Once you start scrolling this will take you through the columns. We are looking for the column which has the LV the most distended (LV end diastolic) and most compressed (LV end systolic). Right click on each of these columns and label them accordingly (normally this is around columns 10 and 20ish).
Now with either the LV ED or SD column highlighted click "auto detect" in the right side of screen options (looks like a target). This will automatically try to outline in the inner and outer margins of the LV and RV.
Now use the tools at the bottom of the tool bar (rubber band is good) to adjust the contours the computer made.
Do this for both columns (ED and ES).
The computer is using these borders to calculate the Ejection fraction, SV and masses (adjusting your contours will changes the numbers).
When satsified hit "save session" in the top right corner.
The report is generated at the tab on the bottom.
Go to the report and in the right upper corner hit the export button to Wichita Rad PACs (unclick the default).
Then export the a sequence of heart images (this has something to do with tells PACS it is an MRI because we exported a document first).
HOW TO DO VELOCITY OF A VALVE:
In vitrea highlight the "flow" and Series of the valve you want to evaluate.
Right click and pick "Q flow"
Click in the middle of the open valve and make a small circle
Right click and "copy and paste all"
Click blue graph button at top, this give the E and A wave
Adjust graph, save and export like above.
WHAT MEASUREMENTS TO MAKE IN PACS:
3-chamber view
aortic root
left atrium AP dimension
4-chamber axial view
long and short axis of RV
short axis of the RA
SA stack fiesta Cine
pick level of LV where papillary muscles start
find a point in the cine of end diastole, then measure the LV wall thickness at 11:00 o'clock.
measure the LV chamber width from 5-11 o'clock (at an angle).
Then measure the same LV chamber width but now in end systole.
Cardiac Size Normals
Men
RA trans 67 mm
RA long 65 mm
RV trans 60 mm
LA ap 50 mm
LA trans 82 mm
LV trans 58 mm
Women
RA trans 64 mm
RA long 60 mm
RV trans 57 mm
LA ap 45 mm
LA trans 75 mm
LV trans 53 mm
Reference:
https://www.ajronline.org/doi/pdf/10.2214/AJR.18.19805
1: Eifer DA, et al. Diagnostic Accuracy of Sex-Specific Chest CT Measurements Compared With Cardiac MRI Findings in the Assessment of Cardiac Chamber Enlargement. AJR Am J Roentgenol. 2018 Nov;211(5):993-999. doi: 10.2214/AJR.18.19805. Epub 2018 Sep 21. PubMed PMID: 30240288.
Valve Stenosis and Regurgitation Criteria
Aortic Stenosis
Aortic jet velocity (m/s) Mean Gradient (mmHg) AVA (cm2) Indexed AVA (cm2/m2)
Normal = less than 2.5 m/s
Mild = 2.6–2.9 m/s less than 20 mmHg more than 1.5 sq cm more than 0.85 sq cm per sq m
Moderate = 3.0–4.0 m/s 20 to 40 mm of Hg 1.0–1.5 sq cm 0.60–0.85 sq cm per sq m
Severe = more than 4.0 m/s more than 40 mmHg less than 1.0 sq cm less than,0.6 sq cm per sq m
Aortic Regurgitation
Mild = regurgitant volume less than 30 mL/beat, regurgitant fraction less than 30%
Moderate = regurgitant volume 30 to 60 mL per beat, regurgitant fraction 30-50%
Severe = more than 60 mL per beat, regurgitant fraction more than 50%
Mitral Stenosis MV area (cm2) Pressure Half-Time (ms)
Normal = >2.0 cm2
Mild = 1.5-2.0 cm2 <90ms
Moderate = 1.0 - 1.5 cm2 90-150ms
Severe = < 1.0 cm2 >150ms
Mitral Regurgitation fraction= calculated by LV stroke volume - ascending aorta forward flow
(%) Regurgitant volume (ml)
mild ≤ 15% <30 ml
moderate = 16-25% 30-50 ml
moderate-severe = 26-48%
severe > 48% >50 ml
Pulmonic Stenosis
Normal = PA velocity is usually less than 1 m/s
Mild = peak jet velocity is less than 3 m/s (peak gradient less than 36 mmHg).
Moderate = peak jet velocity of 3–4 m/s (peak gradient 36–64 mmHg)
Severe = peak jet velocity more than 4 m/s (peak gradient greater than 64 mmHg)
Pulmonic Regurgitation
Mild less than 20%, RV size is normal
Moderate 20-40%, RV size is normal or dilated
Severe more than 40%, RV size is dilated
Tricuspid Stenosis
No one cares...
Tricuspid Regurgitation
Mild less than 30 mL:, RV and RA size usually normal, IVC is normal, less than 2 cm
Moderate 30 to 44 mL, RA and RV size, normal or mild dilatation, IVC is normal or mildly dilated (2.1 through 2.5 cm)
Severe more than equal to 45 mL, RA and RV size usually dilated, IVC usually dilated more than 2.5 cm
Cardiac Hypertrophy
RV = >5mm in diastole
LV = 15mm in diastole
Pericardial thickening = >4 mm (septal bounce on early diastole (NOT systole which is a septal flash from LBBB))
Hypertrophic Cardiomyopathy
Adults = septal wall thickness > 15 mm in end diastole
Ratio of the septal thickness to inferior wall at the midventricular level > 1.5
Children= septal wall thickness is > two standard deviations above the mean for age, sex, or body size (z score ≥ 2)
Papillary muscle hypertrophy = >1.1cm in any dimension
HCM High risk factors on CMR
1. End diastolic wall thickness of more than 30 mm
2. Amount and extent of enhancement (> 15 % volume of myocardium)
3. Apical aneurysm
4. LVOT/mid ventricular obstruction gradient > 30 mm Hg
5. Left atrial enlargement
6. Burned out phase (LVEF< 50 %)
Non-Compaction = Ratio of non-compated to compacted LV >2.3
Athlete's Heart vs HOCM
One of the practical challenges is to differentiate concentric hypertrophy in HCM from the hypertrophy seen in hypertension and in athletic heart. The symmetric increased thickness of the LV in athletic heart is associated with a history of vigorous physical activity, which causes LV hypertrophy with chamber enlargement with preserved LV cavity size of more than 55 mm, and there is no delayed myocardial enhancement in the thickened walls.
Also, since LV hypertrophy in trained athletes is a physiologic adaptation and not a pathologic process, there is a 2–5-mm regression in LV wall thickness in athlete’s heart over a short deconditioning period of about 3 months, which is not seen with concentric HCM.
The majority of hypertension patients have concentric LV hypertrophy with normal ejection fraction and normal chamber size, which can help in differentiation from HCM. The LV wall thickness in hypertensive heart disease also rarely exceeds 16 mm, and usually there is no delayed enhancement.
Left Vent EF
Hyperdynamic = LVEF greater than 70%
Normal = LVEF 50% to 70% (midpoint 60%)
Mild dysfunction = LVEF 40% to 49% (midpoint 45%)
Moderate dysfunction = LVEF 30% to 39% (midpoint 35%)
Severe dysfunction = LVEF less than 30%
ARVD
ARVD criteria:
Arrhythmogenic right ventricular cardiomyopathy.
ARVC task force criteria
Regional contraction abnormality
AND
RV enlargement (more than 110 mL per meter squared) or RV dysfunction (RVEF less than 40 percent)
European heart Journal 2010; 31 (C7): 806-814
Delayed enhancement has been described with ARVC in up to 35 percent of the patients, however, is not a diagnostic criteria, but indicates worse prognosis.
Accordion sign has been described with ARVC, along the inner margin of the lateral free wall of the right ventricle.
Fatty infiltration in the lateral free wall of the right ventricle is a nonspecific and can be seen in asymptomatic people.
Focal aneurysm can be seen with ARVC.
Cardiac MRI is the most sensitive diagnostic imaging modality.
Major cardiac MRI diagnostic criteria are:
regional RV akinesia or dyskinesia or dyssynchronous RV contraction and 1 of the following:
ratio of RV end-diastolic volume to BSA ≥110 mL/m2 (male) or ≥100 mL/m2 (female)
RV ejection fraction ≤40%
Minor cardiac MRI diagnostic criteria are:
regional RV akinesia or dyskinesia or dyssynchronous RV contraction and 1 of the following:
ratio of RV end-diastolic volume to BSA ≥100 to <110 mL/m2 (male) or ≥90 to <100 mL/m2 (female)
RV ejection fraction >40% to ≤45%
MRI may show fatty infiltration in the right ventricle (and occasionally in the left ventricle) 8, but this can also be seen in normal myocardium 3 and is no longer part of the diagnostic criteria 9. A corrugated pattern to the right ventricular wall may be seen, known as the “accordion sign.”
