Nuclear - Image interpretation Flashcards
Describe the findings and cause of the patients symptoms
- 62 yo male with increasing SOB and LE edma
- Projection image in the LAO position from the stress portion of a 1-day-rest/stress Tc99m SPECT MPI study is shown
Pulmonary Hypertension
- marked RV hypertrophy and enlargement
- relative paucity of lung uptake of Tc99m suggests possible COPD (frequent cause of pulmonary hypertension and RVH)
What is the cause of increased lung uptake when using Tl201 with stress?
- severe ischemia
- causes an increase in the lung-to-heart ratio
- Caused by increased PCWP –> extravasation of Tl201 from intravascular space to the interstitial space
- not reported with Tc99m agents
Based on the stress and rest projection images, which radioisotope imaging protocols was most likely use
1-day rest / stress Tc99m
- based on grainy quality of the rest images (low count statistics) –> 1-day study using low-dose rest and high-dose stress
- distribution consistent with Tc99m –> GI track and Liver
Desribe the findings and most likely cause of SOB:
COPD
- marked thickening of the diaphragm recognized as a lucency starting fom the patient’s right abdominal wall and extending all the way to the heart
-
Dark appearance of diaphragm muscle between vascular lungs and liver
- marked hypertrophy of diaphragm in COPD patients
- *
Describe the findings:
- 67 year old male with atypical chest pain
- abnormal baseline EKG
- Exercise SPECT MPI at 13.5 METS without anginal symptoms
Scaling artifact
- circumferential decrease in counts that is most prominent on the short-axis slices relative to resting images
- caused by a very hot apical anterior hot spot
- incorrect scaling –> decreases subendocardial counts and may give the appearance of TID
Describe the findings and next step:
- 60-year old female presents with chest pain to the ER
- Exercise SPECT MPI is performed
Discharge for outpatient follow-up
- normal study by visual and quantitative analysis
Describe the findings:
- 58 year old female with progressive chest pain
- Stress MPI is performed
coronary angiography
- large area of severe ischemia involving the apex, septum, anterior and lateral walls
- TID of the cavity
- High risk scan consistent with:
- proximal LAD or LM disease
- severe MVCAD
Describe the findings:
- 75 year old male with remote MI and atypical chest pain
- Rb82 vasodilator PET study is performed
severe lateral wall ischemia and apical infarction
- large area of severe lateral wall ischemia extending fom the apex to the base
- apical infarction most prominent on the HLA and VLA images
Describe the findings, which artery is likely to be causing the symptoms in this patient?
RCA
Describe the findings:
- 39 year old female with BMI 45 being evaluated for intestinal bypass surgery
- PMH: HTN, DM, dyslipidemia
- Pharmacologic SPECT MPI is performed (without AC) –> severe chest pain without EKG changes
uniform breast attenuation
- images were acquired with a small filed of view camera with the patient sitting upright in a chair with the chest pressed against a stabilizing bar
- raw projection image shows –> large left breast covering the entire heart –> uniformattenuation of the heart and not the focal decrease on the perfusion images seen in the anterior wall when there is only partial coverage of the heart by breast tissue
- Right breast is seen on the right with a bright area in between due to liver and lung background that has less attenuation
- Rotating projection images should be reviewed in cine mode on a workstation as part of QC for every study interpreted
Describe the findings and next step:
- 85 year old female with multiple prior MI’s and CABG presents with worsening heart failure despite optimal medical therapy
- SPECT MPI is performed
PET assessment of hibernation
- extensive and severe areas of absent perfusion on the resting SPECT MPI involving the LAD and RCA territories with only the lateral wall showing perfusion
- No evidence of ischemia
Describe the findings:
- 46 year old female for pre-operative risk assessment
- PMH: DM, HTN, dyslipidemia, obesity (5ft 8-inches tall, 434 pounds)
- Pharmacologic 1-day rest/stress Tc99m perfusion studie with CT AC performed
Normal study
- Apical defect –> apical thinning
- recognized variant in obese patients with large BMI
- due to overrepresentation of counts due to close proximity throughout the 180-degree acquisition is corrected
- Multiple defects in this study (both attenuation –> confirmed by normal motion on gated images)
- uniform breast attenuation
- inferior wall diaphragmatic attenuation
What does a I-mIBG 123 study evaluate?
When is this study utilized?
myocardial sympathetic innervation
abnormal in heart failure syndromes and may be a marker of future cardiac events (including life-threatening arrhythmia and cardiac death)
What I-mIBG 123 finding is associated with the highest risk of cardiac events in heart failure patients?
mIBG heart-to-mediastinum ratio
- calculated as:
- the ratio of counts in a region of interest drawn over the heart
- to the counts in a 7x7 pixel mediastinal reference region
-
uptake ratio < 1.60 correlated with increased time to first occurrence:
- NYHA functional class progression
- Arrhythmia (life-threatening)
- Cardiac death
What are quantiative parameters obtained from I-mIBG 123 imaging studies?
- mIBG washout rate
- measure of retention of the tracer in the myocardium
- mIBG heart-to-mediastinum ratio
Describe the findings and next step:
- 62 year old female with atypical chest pain
- no PMH
- EKG and Troponin are negative
- Exercise Tc99m SPECT MPI
- 10:30 (12 METS) with no chest pain or ischemic changes on EKG
- BP stable
- EF 67%, TID 0.86
Low-risk abnormal SPECT MPI
- Perfusion images:
- mid and distal, inferolateral wall reversible defects
- SDS 4 –> 7% of myocardium affected
- 10% is generally considered the threshold for high-risk or severe ischemia
- Duke treadmill score + 10.5 (low risk)
*
Describe the findings:
Severely abnormal study
- moderate-severe reversible perfusion defects involving the septum and apex (consistent with LAD disease)
- TID ratio 2.00
***MVCAD –> CABG
What is the benefit of rest-only imaging studies
When can it be utilized effectively?
- Simple and rapid protocol
- Cost effective
- Low-Moderate risk acute chest pain
- Normal perfusion study with radiotracer injected during active chest pain
- virtually excludes acute MI
- cannot exclude chronic stable ischemic heart disease
In what patient’s is rest-only imaging not-applicable?
prior MI
- acute myocardial ischemia or infarction cannot be distinguished from an old MI
What are limitations of rest-only imaging protocols?
- Prior MI
- cannot distinguish acute myocardial ischemia/infarction cannot be distinguished from an old MI
- Attenuation artifact cannot be distinguished from myocardial ishcemia
- normal wall motion does not definitively differentiate attenuation from abnormal perfusion (non-transmural infarction can still demonstrate normal wall motion)
- Limited value in identifying acute ischemia after chest pain resolution
What is the timing cut-off for rest-only imaging?
- Active chest pain
- ischemic symptoms resolved shortly ( < 3 hours) before testing
Describe the findings:
- 55 yo AA male presents after a syncopal event (fatigue, SOB, orthopnea, PND and weight gain)
- EKG with complete heart block
- CXR with cardiomegaly and hilar fullness
- Echo: LVEF 35% with global hypokinesis
- LHC: normal coronaries
- N13 / F18-FDG PET is shown
Mismatch of the anteroseptum
- decreased perfusion involving the basal and mid anterior, anteroseptum and inferoseptum with corresponding increased F18-FDG in the same distribution
What is the sarcoidosis spectrum of disease on PET/CT?
- Normal
- normal perfusion / negative FDG
- Non-specific
- normal perfusion / diffuse FDG
- Early disease
- normal perfusion / focal increase of FDG
-
Mismatch pattern
- abnormal perfusion / focal increase in FDG
- Scar
- abnormal perfusion / no FDG uptake
Describe the findings/diagnosis:
- 75 year old AA male with complaints of SOB and fatigue
- PMH: HTN, dyslipidemia, CKD
- Echo: LV thickening, grade 2 diastolic dysfunction, biatrial enlargement
- Tc99m pyrophosphate imaging is shown
ATTR Amyloidosis
- Both semi-quantitative visual scoring and
- grade 2-3 myocardial uptake
-
Heart to contralateral ratio (H/CL) are used in clinical practice
- H/CL > 1.5
- H/CL > 1.6 –> associated with worse survival
Describe the findings/diagnosis:
Pericardial Effusion
- photopenic area seen circumferential to the heart
Describe the findings/diagnosis:
- 55 year old female presents to the ED with chest pain
- PMH: HTN and dyslipidemia
- EKG: deep T wave inversions throughout the anterior leads
- Troponin negative
- Exercise SPECT MPI is performed
Apical hypertrophic cardiomopathy
- characteristic “solar polar” map pattern
- results from increased apical counts at rest secondary to LVH
- stress –> significant decrease in the apical counts with “relative” apical ischemia, even in the absence of CAD
What are high-risk features on SPECT MPI?
- perfusion defects in multiple vascular territories
- increased Tl-201 lung uptake
- LVEF < 40%
- extensive hypoperfusion in one vascular territory
- increased end-systolic and end-diastolic volumes
- TID of LV cavity during stress
Describe the findings and most common use
Equilibrium radionuclide angiocardiography (RNA) / MUGA
Effects of Chemotherapy
What is RNA best utilized for?
Ventricular function (gold standard)
- LV function
- RV function
- Chamber size
- Dyssynchrony
What is the next best step?
Exercise MPI
- MPI added due to LVH with TWI –> may reduce specificity of the test
- additional risk stratification provided by MPI would provide:
- prognostic information
- guidance for revascularization decisions
Describe the findings and next step:
- 58 year old female admitted with worsening DOE and heart failure
- PMH: HTN and DM
- Echo: mid-distal anterior, septal and apical akinesis with mild MR, and LVEF 30%
- Vasodilator Tc99m SPECT: fixed, medium size, severe intensity perfusion defect involving mid to apical anterior, apical septal, mid anteroseptal, and LV walls
- LHC: MVCAD with moderate-severe lesions in mid LAD, proximal RCA, mid-OM2
- N13 / F18-FDG/CT is shown below
CABG - viable myocardium in LAD territory
- Oragne –> viable myocardium
- Green –> non-viable myocardium
Describe the findings and next step:
- 68 year old man with progressive DOE and exertional CP, left hip pain limits exercise capacity
- PMH: obesity, hyperlipidemia, HTN
- Vasodilator N13 PET/CT is performed
- CFR = 1.1
coronary angiography
- TID + CFR < 1.5 =
- suggestive of significant epicardial disease involving the LM, proximal LAD or MVCAD
- alternatively microvascular dysfunction
What is her estimated annual risk of all-cause mortality?
High risk ( > 3%)
- blunted heart rate response (HRR) during a regadenoson MPI study –> significantly increases risk of subsequent death or adverse CV outcomes
What is the annualized risk of death with a blunted HRR during MPI study?
- Abnormal MPI + blunted HRR
- 9.6%
- Normal MPI + blunted HRR
- 7.5% annualized risk of death (high)
- Normal MPI + Normal HRR
- 1.7% if normal HRR
What is the most appropriate next step?
ICD placement
- FDG PET / SPECT MPI performed after 2 meals with no carbohydrates + high fat content + prolonged fasting –> usual protocol to identify inflmmation
- Classic Sarcoidosis imaging findings:
- reduced perfusion and increased FDG uptake
- Focal perfusion defect + abnormal FDG uptake –> increased risk of death/VT
What is the cardiac event rate associated with TID (abnormal study)?
1.8% vs. 0.7%
Describe the findings and next step:
- 50 year old male with burning, substernal chest discomfort that started 2 hours ago
- PMH: obesity, HTN, HLD, GERD, tobacco abuse
- EKG: NSR, nonspecific ST depression
- Troponin negative
- Rest Tc99m tetrofosmin MPI is performed
coronary angiography
- acute rest perfusion imaging:
- large perfusion defect in the inferior/inferolateral wall –> consistent with myocardial ischemia
- abnormal acute rest MPI –> high probability of ACS
- NPV –> 99-100%
- NPV –> exclude cardiac events in medium-term follow up –> 97%
Why is acute resting MPI a useful test in the ER setting?
NPV –> 99-100%
- abnormal acute rest MPI –> high probability of ACS –> LHC
- NPV 97% –> exclude cardiac events in medium-term follow up
- ensures safe discharge for stress testing to be completed a a later time
What are findings on EKG that will preclude use of acute rest MPI?
Q waves –> prior MI
- likely to have resting myocardial perfusion defects –> repeat MPI during a chest pain free period to distinguish new ischemia from old infarct
