Nuclear - Image interpretation

Question 1

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

Answer 1

Pulmonary Hypertension

• marked RV hypertrophy and enlargement
• relative paucity of lung uptake of Tc99m suggests possible COPD (frequent cause of pulmonary hypertension and RVH)

Question 2

What is the cause of increased lung uptake when using Tl201 with stress?

Answer 2

• 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

Question 3

Based on the stress and rest projection images, which radioisotope imaging protocols was most likely use

Answer 3

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

Question 4

Desribe the findings and most likely cause of SOB:

Answer 4

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
  • *

Question 5

Describe the findings:

• 67 year old male with atypical chest pain
• abnormal baseline EKG
• Exercise SPECT MPI at 13.5 METS without anginal symptoms

Answer 5

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

Question 6

Describe the findings and next step:

• 60-year old female presents with chest pain to the ER
• Exercise SPECT MPI is performed

Answer 6

Discharge for outpatient follow-up

• normal study by visual and quantitative analysis

Question 7

Describe the findings:

• 58 year old female with progressive chest pain
• Stress MPI is performed

Answer 7

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

Question 8

Describe the findings:

• 75 year old male with remote MI and atypical chest pain
• Rb82 vasodilator PET study is performed

Answer 8

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

Question 9

Describe the findings, which artery is likely to be causing the symptoms in this patient?

Answer 9

RCA

Question 10

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

Answer 10

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

Question 11

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

Answer 11

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

Question 12

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

Answer 12

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

Question 13

What does a I-mIBG 123 study evaluate?

When is this study utilized?

Answer 13

myocardial sympathetic innervation

abnormal in heart failure syndromes and may be a marker of future cardiac events (including life-threatening arrhythmia and cardiac death)

Question 14

What I-mIBG 123 finding is associated with the highest risk of cardiac events in heart failure patients?

Answer 14

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

Question 15

What are quantiative parameters obtained from I-mIBG 123 imaging studies?

Answer 15

• mIBG washout rate
  
  • measure of retention of the tracer in the myocardium
• mIBG heart-to-mediastinum ratio

Question 16

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

Answer 16

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)
  *

Question 17

Describe the findings:

Answer 17

Severely abnormal study

• moderate-severe reversible perfusion defects involving the septum and apex (consistent with LAD disease)
• TID ratio 2.00

***MVCAD –> CABG

Question 18

What is the benefit of rest-only imaging studies

When can it be utilized effectively?

Answer 18

• 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

Question 19

In what patient’s is rest-only imaging not-applicable?

Answer 19

prior MI

• ​acute myocardial ischemia or infarction cannot be distinguished from an old MI

Question 20

What are limitations of rest-only imaging protocols?

Answer 20

• 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

Question 21

What is the timing cut-off for rest-only imaging?

Answer 21

• Active chest pain
• ischemic symptoms resolved shortly ( < 3 hours) before testing

Question 22

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

Answer 22

Mismatch of the anteroseptum

• decreased perfusion involving the basal and mid anterior, anteroseptum and inferoseptum with corresponding increased F18-FDG in the same distribution

Question 23

What is the sarcoidosis spectrum of disease on PET/CT?

Answer 23

• 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

Question 24

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

Answer 24

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

Question 25

Describe the findings/diagnosis:

Answer 25

**Pericardial Effusion** * photopenic area seen circumferential to the heart

Question 26

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

Answer 26

**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

Question 27

What are high-risk features on SPECT MPI?

Answer 27

* 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

Question 28

Describe the findings and most common use

Answer 28

**Equilibrium radionuclide angiocardiography (RNA) / MUGA** **Effects of Chemotherapy**

Question 29

What is RNA best utilized for?

Answer 29

**Ventricular function (gold standard)** * LV function * RV function * Chamber size * Dyssynchrony

Question 30

What is the next best step?

Answer 30

**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

Question 31

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

Answer 31

**CABG - viable myocardium in LAD territory** * Oragne --\> viable myocardium * Green --\> non-viable myocardium

Question 32

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

Answer 32

**coronary angiography** * TID + CFR \< 1.5 = * suggestive of significant epicardial disease involving the LM, proximal LAD or MVCAD * alternatively microvascular dysfunction

Question 33

What is her estimated annual risk of all-cause mortality?

Answer 33

**High risk ( \> 3%)** * **blunted heart rate response (HRR) during a regadenoson MPI study** --\> significantly increases risk of subsequent death or adverse CV outcomes

Question 34

What is the annualized risk of death with a blunted HRR during MPI study?

Answer 34

* 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

Question 35

What is the most appropriate next step?

Answer 35

**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

Question 36

What is the cardiac event rate associated with TID (abnormal study)?

Answer 36

**1.8%** vs. 0.7%

Question 37

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

Answer 37

**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%

Question 38

Why is acute resting MPI a useful test in the ER setting?

Answer 38

**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

Question 39

What are findings on EKG that will preclude use of acute rest MPI?

Answer 39

**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**