Get documents about "Stress MRI
Document Sample
Stress MRI
What is its role and Is It Practical?
Mouaz Al-Mallah, MD MSc FACC FAHA FESC
Associate Professor of Medicine, Wayne State University, Detroit, USA
Director,
Director Advanced Cardiovascular Imaging
King Abdul Aziz Cardiac Center
Riyadh, Saudia Arabia
5 Things You Need to Know About
Magnetic Resonance Imaging
• The magnet is ALWAYS ON
• No ionizing radiation
• MR contrast agents are not nephrotoxic
– Contraindication in chronic renal failure because of
p g y (
nephrogenic systemic fibrosis (NSF) )
– Excellent soft tissue contrast even without contrast
y g g
• Body habitus does not interfere with imaging if the
patient can just fit! Most magnets accommodate 350-
400 lbs
• Nearly 10% of patinets are claustrophobic , So ask
your patient!!!!!!!
72 yo man with exertional chest tightness
and mild SOB over 3 months
T.C.
Cath:
mLAD 70%
RCA prox total with collaterals
Dom prox LCx total with collaterals
Dobutamine combined Cine Function and
Perfusion P t
P f i Protocol l
Rest and
Localize Stress Perfusion Recovery Delayed Imaging
Function
Progressive stages of 15 min 10 min
Dobutamine + atropine stress (20 min)
Dobutamine MRI Protocol
Atropine 0.5 mg,
repeat 0.25 q minute
40
30
20
10
Dobutamine 5
dose
(mcg/kg/min)
0 3 6 9 12 15
Time (min)
BP
ECG
CP985547-9
y
Safety of Dobutamine Stress MRI
• 1,000 consecutive DCMR tests over 5 years
evidence
• More than 50% had e idence of ischemia
• 10 side effects occurred in 6.4%
– t i d ti l t h di ti t)
sustained ventricular tachycardia (1 patient)s 0 1%
0.1%
– nonsustained ventricular tachycardia 0.4%
– paroxysmal atrial fibrillation 1.6%
1 6%
– transient second degree AV block 2:1 0.2%
– (
Severe increase in BP (>240/120 mmHg) g) 0.5%
– decrease in systolic BP >40 mmHg 0.5%
– nausea 3.1%
2004;25:1230–
Eur Heart J 2004;25:1230–1236
Use of Dobutamine Cine MRI for
Detection f I h i
D t ti of Ischemia
N = 172 DSE DSMR P value
Sensitivity 74.3% 86.2% <0.05
Specificity 69.8% 85.7% <0.05
81 0%
81.0% 91.3%
91 3% <0.05
<0 05
PPV
61.1% 78.3% <0.05
NPV
Accuracy 72.7% 86.0% <0.05
Nagel E et al. Circulation 1999
Diagnostic Accuracy of
Dobutamine
D b t i MRI
h
Author Year n Sensitivity Specificity A
S i i i S ifi i Accuracy
Pennell 1992 25 91%
Baer
B 1994 26 85%
Van Ruggee 1994 39 91% 80% 90%
Nagel 1999 172 86% 86% 86%
Hundley 1999 41 83% 83% 83%
Paetsch 2004 79 89% 80% 86%
Wahl 2004 160 89% 84% 88%
Adapted from CV MRI Kwong et al., 2008
Prognostic Value Dobutamine MRI
p , q y
279 patients, Poor DSE quality
Multivariate Predictors of all cause mortality or Hundley et al. Circulation 2002
CV death/MI were EF and ischemia
MRI Vasodilator Perfusion
FPMP FPMP
C di
Cardiac R i l
Regional t
at Delayed
During
localization Function Rest Enhancement
vasodilating
stress
Saturation Prep
i SSFP Imaging MDE
EPI-fgre FPMP Short/Long Axis Gd-DTPA
Matching SAX views
1 R-R (accumulative
3-4 SAX views 0.15 mmol/Kg)
Gd-DTPA 0.05-
0.075mmol/kg
at 5 ml/sec
80 year old lady with chest pain, SOB
STRESS
REST
Dynamic First Pass Perfusion Exam
Regional Defects Indicate Ischemia
LAD
RCA
LCX Mid
Apex
Base
t i t i
LAD 100% stenosis, RCA 60% stenosis
Perfusion Quality Control
Is th b l ti ht h?
I the bolus tight enough?
Bad Bolus:
Good Bolus • Leaky IV
• Slow injection rate
• Low ejection fraction
• Pulmonary disease
• Intracardiac shunt
Semi-quantitative MR Perfusion
300
250
ensity
LV signal
200
gnal Inte
Occluded
150 region
Normal region
100
Sig
50
Occluded region
Normal
0 region
0 5 10 15 20 25 30 35 40 45
Time (seconds)
Diagnostic Accuracy
patients
47 patients, 33 Without Known CAD
Sensitivity Specificity Accuracy
Overall 87% 89% 82%
1V Disease 100% 94% 96%
2V Disease 71% 83% 75%
Grafts 100% 75% 90%
Sensitivity Specificity Accuracy
DE 48% 94% 76%
Cine 74% 93% 86%
Stress perf 81% 90% 87%
Ab
Above 3 89% 88% 88%
Cury et al., Radiology 2006; 240:39–45
p
Interpretation of MRI Perfusion
Sensitivity Specificity Accuracy
Algorithm 89% 87% 88%
Perfusion 84% 58% 63%
Cine 49% 73% 63%
DE 49% 98% 78%
2006;47:1630-
Klem et al., J Am Coll Cardiol 2006;47:1630-8
Schwitter et al., Eur Heart J 2008;29:480–489
Schwitter et al., Eur Heart J 2008;29:480–489
Diagnostic
Performance
of CMR vs.
all SPECT
and gated
SPECT
Schwitter et al., Eur Heart J 2008;29:480–489
Schwitter et al., Eur Heart J 2008;29:480–489
Prognostic Value of Perfusion MRI
Bodi et al., JACC 2007;50:1174–9 Jahnke et al., Circulation.
2007;115:1769-
2007;115:1769-1776.
Perfusion MRI at 3T
Saturation-recovery spoiled gradient-echo
101 patients, Prevalence of CAD 69%
Sensitivity Specificity Accuracy
Patient-based 90% 71% 84%
Vessel-based 76% 89% 86%
LAD 83% 86% 85%
LCX 75% 91% 88%
RCA 68% 91% 85%
In 24% of patients without DE, dark rim artifacts
were detected, mostly in the LAD territory (56%)
Gebker et al Radiology: Vol 247: 1 April 2008
Dark Rim Artifact
Subendocardial perfusion defect during A, stress and B,
rest in absence of scar (C) at DE. Patient had no relevant
ste os s coronary angiography.
stenosis at co o a y a g og ap y
Gebker et al Radiology: Vol 247: 1 April 2008
Perfusion MRI at 3T
• 61 patients referred for elective coronary
angiography
• Patients underwent Adenosine perfusion MRI at
p
1.5T ad 3T
• Four short-axis images were acquired during
every heartbeat using a saturation recovery fast-
gradient echo sequence and 0.04 mmol/kg Gd-
DTPA bolus injection
Qualitative Perfusion l i by blinded
• Q lit ti P f i analysis b 2 bli d d
readers
• The prevalence of CAD was 66%
Cheng et al., J Am Coll Cardiol 2007;49:2440–9)
Perfusion MRI at 3T
61 patients, 66% CAD prevalence
1.5 T 3T
y
Sensitivity 90% 98%
Specificity 67% 78%
PPV 84% 89%
NPV 78% 94%
Accuracy 82% 78%
Cheng et al., J Am Coll Cardiol 2007;49:2440–9)
Perfusion MRI at 3T
Diagnostic Accuracy: 1V Disease
1.5 T 3T
y
Sensitivity 68% 90%
Specificity 71% 88%
PPV 52% 77%
NPV 83% 95%
Accuracy 71% 89%
Cheng et al., J Am Coll Cardiol 2007;49:2440–9)
Perfusion MRI at 3T
Diagnostic Accuracy: Multi-vessel Diseases
1.5 T 3T
y
Sensitivity 71% 95%
Specificity 93% 95%
PPV 83% 91%
NPV 86% 97%
Accuracy 85% 95%
Cheng et al., J Am Coll Cardiol 2007;49:2440–9)
Advantages of Perfusion MR
The bili b i i bili df i d f
• Th ability to obtain viability and function data from
one test that can be performed in 1 – 1.5 hrs
• Possible superior performance in multivessel disease
p (
patients vs. SPECT (balanced ischemia in SPECT as
high as 11% in some series)
• Lack of radiation
Disadvantages of Perfusion MR
• Higher cost and limited availability
• Limits on Gad dosing in CKD patients
holding
• More difficult on patients (breath holding,
claustrophobia)
• Newer kid on the block (learning curve)
