CT Chapter 7 Flashcards
How many high-grade luminal stenoses ( >70%) are present?
1
- High-grade stenosis of the distal RCA (small arrow)
- distal to origin of the PDA, therefore it is called the “right posterolateral branch (RPLB)”
- Second plaque
- calcified and non-calcified plaque that is not a high-grade stenosis
Describe the findings and next step:
- 58 year old with history of HTN referred for CCTA with 3-month history of episodic chest burning unrelated to exertion
Myocardial bridging - Reassurance
- The reformats initially appear to demonstrate a large, bulky, non-calcified plaque in the proximal LAD
- However, the short axis view reveals segment to be buried within the myocardium
- Curved MPR –> typical appearance of these intramyocardial vessels
What is one CCTA predictor of post-procedural MI in patients undergoing elective PCI?
Plaque Attenuation
- volumes of low and moderate density plaque attenuation are larger in patients suffering from post-procedure myocardial injury
- Likely causative roles:
- Distal plaque component embolization
- higher lipid laden plaque components
What type of post-processing methods were used to generate the reformatted image shown below?
Multiplanar reformatting and thin slab MIP (5 mm)
- helps to obtain a LA projection of the RCA
What is the best acquisition parameters for CAC?
- Axial
- Prospective ECG triggered
- at 120 kVp
- Mid-late diastole
- 2.5-3.0 mm slices
-
medium-sharp reconstruction filter kernel without edge enhancement
- provides moderate image noise in low-dose acquisition protocols
What is one major limitation of volume rendered images?
degree of stenosis cannot be determined by these images alone
What patient is CAC most appropriate for?
- Asymptomatic
- Intermediate 10-year ASCVD
What parameter allows differentiation between the two?
- total occlusion
- high-grade, but still-patent stenosis
Length
- > 9 mm –> complete occlusions
- CT read:
- completely thrombosed LAD
Describe the view and findings:
- Axial, Horizontal Long Axis
-
Mitral annular calcification
- RCA calcification (single arrow)
Why is stent imaging currently not recommended?
- Beam Hardening Artifact
- Blooming Artifact
What is the only appropriate imaging of coronary stents?
- Asymptomatic
- LM stent ► 3.0 mm
Describe the findings:
Vein Graft (proximal anastomosis)
In the evaluation of a stent for in-stent restenosis, how does the CT density (HU value) within the stent lumen compare to that of the segment proximal to the stent if the stent is occluded?
Lower
- thrombus and/or intimal hyperplasia (intimal tissue) are hypodense materials –> decreased CT density
Describe the findings:
What is the role of CCTA as it pertains to evaluating for ischemic heart disease in the setting of heart failure?
May offer a valid alternative to invasive angiography in diagnosing ischemic heart failure in patients with reduced EF
- 93 patients with dilated CMP (uncertain etiology)
- CAD prevalence: 46%
- CCTA:
- 90% sensitivity
- 97% specificity
- 100% of 3vCAD/LM were correctly identified
What is the best interpretation of the findings:
- Cross-section of non-calcified atherosclerotic plaque in the LMCA
- Low density region within this plaque displays attenuation < 50 HU
No conclusion can be drawn from these specific numbers
- plaque densities vary with scan conditions
- absolute HU attenuation is not necessarily indicative of a certain plaque type
Describe the findings:
Coronary Sinus
- coronary sinus is the distal-most portion of the great cardiac vein
- located in the posterior portion of the left AV groove
- great cardiac vein + tributaries (from lateral and posterior cardiac veins –> coronary sinus (drains into RA)
What is the overall diagnostic accuracy of cardiac CT for depicting in-stent restenosis in this stent?
- 52 year old male with h/o PCI and recurrent chest pain
98%
- CT provides excellent evaluation of ostial stents
- Evaluation of LMCA stents, without extension into major side branch –> 98% accuracy
- side branch stenting –> 83% accuracy
Describe the findings and most likely finding on coronary angiorgram
Occlusion in LCFx territory
- CT findings:
- regional thinning of the posterolateral wall of the LV
- characteristic of chronic infarct
- Cornary angiogram:
- occlusion of OM or PLB of CFx
- occasionally can be due to distal occlusion of large RCA
What are the current recommendations for serial calcium scans?
Not recommended
- due to:
- uncertainty regarding its benefit
- variability of results from scan-to-scan
Describe the findings:
??Conus branch??
Describe the CT scan protocol/view:
Oblique MIP of the RCA
Describe the RCA findings in this image:
Cardiac Motion Artifact
- likely due to irregularity of HR
- Internal mammary artery is not affected –> rules out breathing artifact
What situation would produce respiratory motion artifact but not necessarily affect the appearance of the chest wall?
Isolated diaphragmatic motion
Describe the findings:
ARCAPA
- anomalous origin of right coronary artery from the pulmonary artery
- in these cases, extensive collateral circulation from the L-to-R develops to ensure delivery of oxygenated blood to the myocardium subtended by the RCA
- LAD is markedly dilated as a compensatory mechanism to supply collaterals to the RCA
Why is the RCA not seen in the posterior groove (arrow)?
Left dominant circulation
- PDA is seen to arise form the CFx
What is one current limitation or considered an “uncertain” indication in cardiac ct?
What are common appropriate indications?
myocardial viability assessment]
- Evaluation of pulmonary vein anatomy prior to AF ablation
- Coronary vein mapping prior to placement of Bi-V pacemaker
- Localization of CABG grafts prior to redo cardiac surgery
Describe the lumen obstruction in the proximal LAD
Diffuse calcification with mild lumen narrowing
- CCTA –> diffuse calcification
- Angiogram –> mild lumen narrowing
Describe the findings
SCAD
- symptoms classically start immediately following strenuous exercise or exertion
- Both CCTA and LHC may be unremarkable given the microscopic sized intimal tear or intramural hematoma
- Diagnosis –> IVUS or OCT
- Treatment –> usually conservative
What is the clinical significance of the finding present in this image from a patient scheduled for coronary bypass surgery?
It may alter the surgical approach to the sternotomy
- Patient already had a CABG:
- sternal wire seen surrounding the sternum
- SVG is seen coursing directly behind the midline sternum –> along the wall of the RA
- SVG is at risk of being transected during repeat sternotomy
- CT findings:
- PPM leads in RA and left lateral wall (BiV)
Describe the findings
and
best ways to optimize the image?
- CT findings:
- 4 mm MIP
- Mixed calcified and non-calcified plaques in the LAD and LCx distributions
- Image optimization:
- Thinnest slice possible –> reduces blooming artifact
- Sharp kernel reconstruction –> provides best spatial resolution
- Wider window width –> reduces volume averaging artifact from calcium
*****Smoother reconstruction kernel –> would not reduce blooming artifact from calcified lesions
Describe the findings
SA nodal artery
- CT findings:
- thin-slab MIP
- most common course of SA node
- 60% - RCA
- 40% - CFx
- supplies arterial blood to the area of the crista terminalis in the RA where the SA nodal complex resides
Describe the view and findings
Axial - Thin slab MIP
Describe the findings
- Severe coronary calcification throughout
- LM and LAD
- do not show any luminal stenosis
- RCA
- severely calcified
- high-grade luminal stenosis proximally
What is the threshold applied for which pixels with a CT value above this will represent coronary calcification?
130 HU
Describe the findings
- CT image:
- 3D volume rendered image of RCA
- Anomalous origin of the RCA above the SinoTubular junction
- no significant ischemic consequences have been reported with this anomaly
Describe the findings
LAD is occluded proximally
How does CCTA compare with myocardial perfusion scintigraphy in predicting subsequent cardiac events if both are normal?
Equally predictive (or “have equal prognostic value”)
- survival analyses demonstrate comparable risk stratification for:
- CCTA <– anatomic CAD
- MPI <– functional perfusion
- anatomic and functional measures were synergistic for the prediction of death or MI
- plaques composition was an important variable for predicting outcomes
Describe the findings:
- LM
- high-grade stenosis
- Proximal LAD
- mild lesion with positive remodeling
Describe the findings and expected coronary anatomy
- CT findings:
- LV apical thrombus
- Coronary anatomy (expected)
-
LAD occlusion
- recent anterior infarction, as apical segments are supplied by LAD
- no associated wall thinning to suspect old, chronic infarction
-
LAD occlusion
Based on this image, the previous coronary bypass procedure most likely utilized which of the following blood vessels?
Two arterial grafts (IMA) and at least one vein graft
- there are no vessels in the chest wall adjacent to either border of the sternum –> both IMA’s have been used as arterial grafts
- one vein graft anastomosis (in a somewhat atypical position) can be seen
Describe the findings
Non-calcified plaque with positive remodeling
- low attenuation signal adjacent to the contrast enhanced lumen
- “positive remodeling”
- diameter of contrast enhanced lumen (artery) + non-calcified plaque –> larger than proximal and distal reference segments
- outward expansion of the plaque
- can occur early in the atherosclerotic process
Describe the findings
Both the stent and raminder of the vessel appear to be free of significant stenoses
- 3.5 mm diameter stent in the proximal LAD –> patent contrast-enhanced lumen without in-stent restenosis or significant beam hardening artifacts
Describe the findings
Short axis
Describe the findings:
RCA stent - not able to be assessed
- image quality is degraded by motion artifact
What procedure is being performed based on the measurement shown?
TAVR
- important measures:
- aortic annulus - to - LMCA and RCA ostia
- aortic root dimensions
- sinus of Valsalva
- sino-tubular junction
****cases of MI secondary to prosthesis deployment across the coronary ostia have been reported