Imaging Pearls ❯ Cardiac ❯ Surgery
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- “Pseudoaneurysms arising from the saphenous venous graft (SVGs) are an uncommon complication of the coronary artery bypass graft (CABG). Although angiography is the gold standard, computed tomography angiography (CTA) of the coronary arteries is the most efficient modality to diagnose these cases and their associated complications. Among numerous possible complications of SVG pseudoaneurysms, local mass effect on the cardiac chambers, adjacent pulmonary vasculature or coronary arteries/bypass grafts have been described. Cinematic rendering, an advanced post-processing technique can be valuable for problem solving in complex cases. In this pictorial essay, we report 3 CT cases of SVG pseudoaneurysms that demonstrate a range of CT imaging appearances of SVG pseudoaneurysms and related complications. Additionally, we will emphasize the applications of cinematic rendering in visualization of complex post-surgical cardiovascular pathology.”
Applications of Cinematic Rendering in the Diagnoses of Compressive Complications of Saphenous Venous Graft Pseudoaneurysms: A Pictorial Essay
Muhammad Umair, MD*, Elliot K. Fishman, MD, Stefan L. Zimmerman, MD
Current Problems in Diagnostic Radiology 000 (2022) 1 5 (in press) - “Saphenous vein grafts (SVG) are commonly used for coronary arterial bypass grafts. Pseudoaneurysms arising from the SVGs are an uncommon complication of the procedure. Their true incidence is unknown, given that many of these pseudoaneurysms are clinically silent and go unrecognized for years. Factors suggested to contribute to the formation of SVG pseudoaneurysms include atherosclerotic degeneration, increased wall shear stress, and vessel wall ischemia secondary to the disruption of the vasa-vasorum during harvesting and grafting process.1 There are no screening recommendations for this complication given low incidence and silent course. The overwhelming majority of these pseudoaneurysms are detected incidentally on chest imaging for other reasons as they are mostly asymptomatic.”
Applications of Cinematic Rendering in the Diagnoses of Compressive Complications of Saphenous Venous Graft Pseudoaneurysms: A Pictorial Essay
Muhammad Umair, MD*, Elliot K. Fishman, MD, Stefan L. Zimmerman, MD
Current Problems in Diagnostic Radiology 000 (2022) 1 5 (in press) - “Compression of various intra-thoracic structures by large SVG pseudoaneurysms is one of the most recognized complications of this condition. This includes compression of cardiac chambers with or without hemodynamic compromise, compression of adjacent coronary arteries and other bypass grafts, pulmonary arteries, and other intrathoracic vascular structures. Additional complications of the SVG pseudoaneurysms include fistula formation to adjacent structures and rupture. Both CTA coronary angiography and invasive angiography can show the compressive complications of SVG pseudoaneurysm, although CTA is preferred due to better delineation of boundaries of adjacent anatomic structures.”
Applications of Cinematic Rendering in the Diagnoses of Compressive Complications of Saphenous Venous Graft Pseudoaneurysms: A Pictorial Essay
Muhammad Umair, MD*, Elliot K. Fishman, MD, Stefan L. Zimmerman, MD
Current Problems in Diagnostic Radiology 000 (2022) 1 5 (in press) - “SVG pseudoaneurysms are a known but uncommon complication of SVG grafting in CABG. CTA of the coronary arteries is the modality of choice for diagnosing this entity and associated complications. We demonstrate 3 imaging examples of utilization of cinematic rendering (CR) to demonstrate complex anatomical details of the mass effect and compression related complications associated with SVG pseudoaneurysms. A side-by-side comparison with conventional volume rendering (VR) is also performed in 1 case for perspective and to show improved comparative visual appeal of the CR given better depth perception and more natural appearing illumination.”
Applications of Cinematic Rendering in the Diagnoses of Compressive Complications of Saphenous Venous Graft Pseudoaneurysms: A Pictorial Essay
Muhammad Umair, MD*, Elliot K. Fishman, MD, Stefan L. Zimmerman, MD
Current Problems in Diagnostic Radiology 000 (2022) 1 5 (in press)
- “CT is a useful technique as part of a multi-modality approach in the evaluation of LVADs and associated complications. Recent studies continue to build on the prognostic role of measuring skeletal muscle CT attenuation in predicting adverse LVAD outcomes, and on the value of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) in the evaluation of suspected LVAD infection. Though CT is very useful for the diagnosis of outflow graft obstruction, it often lacks the diagnostic capability to differentiate between intraluminal thrombus and extrinsic compression from biodebris accumulation. Newer CT techniques such as dual-energy CT and metal artifact reduction algorithms, though promising, lack high-quality published literature on their use in LVAD imaging.”
Update on CT Imaging of Left Ventricular Assist Devices and Associated Complications
Pratik S. Velangi et al.
Current Cardiovascular Imaging Reports 2022 (in press) https://doi.org/10.1007/s12410-022-09570-0 - “LVAD infections can occur on body surfaces in proximity to the device or on device hardware itself. Driveline infections can extend deeper to involve the pump or other components. They are often seen as rim-enhancing fluid collections, soft tissue stranding, or gas pockets adjacent to device components. Though the incremental value of cardiac CT in addition to echocardiography is being recognized for the diagnosis of prosthetic heart valve endocarditis in non-LVAD patients its diagnostic accuracy for infection in LVAD patients is limited due to device-related artifacts.”
Update on CT Imaging of Left Ventricular Assist Devices and Associated Complications
Pratik S. Velangi et al.
Current Cardiovascular Imaging Reports 2022 (in press) https://doi.org/10.1007/s12410-022-09570-0 - “Recent studies continue to build on the prognostic role of measuring skeletal muscle CT attenuation in predicting adverse LVAD outcomes, and on the value of 18F-fluorodeoxyglucose positron emission tomographycomputed tomography (FDG PET-CT) in the evaluation of suspected LVAD infection. Though CT is very useful for the diagnosis of outflow graft obstruction, it often lacks the diagnostic capability to differentiate between intraluminal thrombus and extrinsic compression from biodebris accumulation. Newer CT techniques such as dual-energy CT and metal artifact reduction algorithms, though promising, lack high-quality published literature on their use in LVAD imaging.”
Update on CT Imaging of Left Ventricular Assist Devices and Associated Complications
Pratik S. Velangi et al.
Current Cardiovascular Imaging Reports 2022 (in press) https://doi.org/10.1007/s12410-022-09570-0
- Acute Mediastinitis: Etiology
- Postoperative complications
- Esophageal perforation
- Extension of osteomyelitis from adjacent bone
- Descending necrotizing mediastinitis
- Hematogenous spread of infection - Acute Mediastinitis: CT Findings
- Increased attenuation of mediastinal fat
- Free gas bubbles in the mediastinum
- Localized fluid collections
- Enlarged lymph nodes
- Pleural effusions
- Empyema
Nonvascular, Nontraumatic Mediastinal Emergencies in Adults: A Comprehensive Review of Imaging Findings
Katabathina VS et al.
RadioGraphics 2011; 31:1141-1160 - “ Acute mediastinitis occurs in 0.5%-5% of patients who underwent median sternotomy and has a reported mortality rate of 7%-80%. Staphylococcus aureus is the most common causitive microorganism of postoperative acute mediastinitis.”
Nonvascular, Nontraumatic Mediastinal Emergencies in Adults: A Comprehensive Review of Imaging Findings
Katabathina VS et al.
RadioGraphics 2011; 31:1141-1160
- Complications of Aortic Valve Replacement
- Paravalvular or valvular regurgitation
- Dehiscence
- Endocarditis and abscess formation
- Valve obstruction (thrombus and pannus)
- Structural failure
- Pseudoaneurysm formation
- Aortic dissection
- Hemolysis
- “PhyZiodynamics, a non-rigid registration based algorithm, introduces an opportunity to re-evaluate the CT scan and its role in cardiac imaging, ultimately offering more information- both functional and anatomical- about the heart.”
PhyZiodynamics: A Revolutionary Approach for Post Processed Noise Reduction, Motion Coherence and functional Analytics
H Brown
Ziosoft Inc. - The technique uses a deformable registration model which allows
1. Differentiate noise vs. real data in order to minimize the noise (and hopefully allow dose reduction).
2. Intelligently interpolate additional phases to increase the fidelity of dynamic functional images for greater motion coherence.
3. Enable future functional analytic applications such as surface velocity mapping and multi-modality fusion. - PhyZiodynamic Noise Reduction
-Reduces image noise without compromising spatial resolution
-Post processing technique that can enhance data sets from iterative reconstruction techniques
-Noise reduction is in the 33% range in preliminary studies - Motion Coherence
“PhyZiodynamics allows the user to generate up to 9 additional phases between the original adjacent phases for motion coherence. The supercomputing foundation of PhyZiodynamics processes the computationally intense optical flow algorithm and allows the user to interactively manipulate the 50-phase data set. While PhyZiodynamics does not alter the temporal resolution which is determined at the scanner, it improves the fidelity of biological motion of the cardiac cycle by increasing the frame rate.” - Functional Analytics
With multi-phase data sets, PhyZiodynamics tracks the motion from voxel-to-voxel to calculate displacement, velocity and acceleration. The kinematics are displayed as a parametric map that is overlaid on the volume rendered surface and can be manipulated while in motion providing 5D imaging of the heart "In patients with severe heart failure, LVADs have become a more widely used treatment option as a bridge to heart transplantation, as destination therapy, and as a bridge to myocardial recovery. It is important to have an understanding of the components of such devices and their normal imaging features."
CT of Left Ventricular Assist Devices
Carr CM et al.
RadioGraphics 2010; 30:429-444- Left Ventricular Assist Devices (LVADs): Clinical Use
- As a bridge to heart transplantation
- As destination therapy for patient ineligible to receive a transplant
- As a bridge to myocardial recovery - Complications of Left Ventricular Assist Devices (LVADs)
- Inflow and outflow cannula complications
- Postoperative hemorrhage
- Pericardial tamponade
- Thrombus formation
- Aortic valve stenosis
- Aortic valve insufficiency
- Right sided heart failure
- Infection