Cardiovascular Imaging

Transcription

1 Cardiovascular Imaging

2 Cardiovascular Imaging Cardio and Vascular Imaging Vascularization / Angiogenesis Cardiovascular Imaging metabolic imaging of the heart myocardial perfusion imaging Cardiac CT

3 Vascularization / Angiogenesis Vascularization / Angiogenesis Developmental Angiogenesis Tumor Angiogenesis

4 Developmental Angiogenesis Misclassification of vascular anomalies remains common despite fundamental pathologic differences An accurate distinction is important for management: Though most hemangiomas spontaneously resolve, approximately 10-20% will warrant pharmacologic, surgical, or laser intervention Percutaneous sclerotherapy or more invasive transarterial embolization is used to treat vascular malformations depending on whether the lesion is high-flow or low-flow

5 Vascular Anomaly Diagnosis Most often a clinical diagnosis Radiologic imaging provides a role in challenging cases and can be used to assess the depth and extent of the lesion Ultrasound: provides excellent characterization of superficial structures and hemodynamics MRI: single best exam due to its strong soft tissue contrast and ability to define extent of the lesion and involvement with nearby structures

6 Hemangioma 2 year old female left gluteal hemangioma Spectral color doppler US image demonstrates a well-defined heterogenous mass with arterial waveform Sagittal T1W with fat saturation post contrast MR image demonstrates avid and homogenous enhancement of the mass

7 Arteriovenous Malformation 12 week old female right scapular AVM Spectral color Doppler US image demonstrates a waveform typical for low arterial resistance with arterialization of the draining veins Coronal T1 with fat saturation post contrast MR image demonstrate avid enhancement of the lesion

8 Tumor Angiogenesis Molecular imaging of the αvβ3 integrin: A - SPECT B - PET C - optical imaging D - MRI E - xenograft tumor after injection of microbubbles conjugated with ariginine-glycine-aspartic acid (RGD) F - xenograft tumor after injection of microbubbles conjugated with scrambled control peptide G - presence of single microbubbles after injection of αvβ3-targeted microbubbles

9 Tumor Angiogenesis Dynamic contrast enhanced MRI (DCE_MRI) Technique where enhancement of a tissue or organ is continuously monitored using MRI after bolus IV contrast medium Low molecular weight contrast media (<1 kda) Diffuse into extravascularextracellular space (does not cross cell membranes) Experiment lasts a few minutes David Collins and Ian Judson, Institute of cancer Research, London

10 Basics of DCE-MRI

11 Basics of DCE-MRI T 2 *W DCE-MRI of Mixed Mullerian Tumour Typical acquisition 1-2 mins

12 Cardiovascular Imaging Myocardial Perfusion

13 Myocardial Perfusion Schematic representation of interpretation of myocardial perfusion images Shaded areas indicate myocardial perfusion defects

14 Myocardial Perfusion Summed images are used to assess cardiac perfusion. Rest and Stress images are compared to determine if a region of the heart is ischemic starved of oxygen In the study below, the rest image indicates normal blood flow, but the stress image indicates abnormal blood flow in the Inferior-lateral region. Stress Rest This may indicate ischemia in this region of the heart which is supplied by the LCX (left circumflex artery). There may be stenosis in that coronary artery.

15 Myocardial Perfusion SA HLA VLA Gated images are made possible by ECG-gated SPECT Physicians can now access cardiac function: Wall motion does the LV contract uniformly? Ejection Fraction does the LV pump out enough blood to the body?

16 Myocardial Perfusion 82Rb PET: left normal; right abnormal perfusion study

17 Myocardial Perfusion

18 Cardiac CT Clinical Scanners High temporal and spatial resolution Gantry rotation times of 420 ms or shorter Spatial resolution of 0.4 by 0.4 by 0.4 mm state-of-the-art equipment for CTA Breath hold is 6 to 12 s

19 Cardiac CT Coronary Artery Calcium Scanning Non-contrast study Refine clinically predicted risk of CHD beyond that predicted by standard cardiac risk factors Used in asymptomatic patients Coronary calcium Present in direct proportion to extent of atherosclerosis Minority (20%) of plaque is calcified

20 (a) Coronal scout; (b) enddiastolic image in axial projection; (c) end-diastolic image on long vertical axis; (d) end-diastolic image on long horizontal axis; (e) end-diastolic image on long vertical axis that is used in alternative for obtaining images on the short axis; (f) end-diastolic image on short axis at medium ventricular level that is used in alternative for obtaining images on the long horizontal axis Cardiac MRI Quantitative Data on ventricular chambers

21 Myocardial Metabolism Fatty Acid Metabolism

22 Myocardial Metabolism Fatty Acid Metabolism Serial dynamic images (2 mm per frame) of myocardiumafter administra tion of [â 1C]palmitatotehealthy volunteer. Note high myocardial uptake in early stage, with rapidwashoutfrom myocardium.

23 Myocardial Metabolism Fatty Acid Metabolism Series of short-axisslices of (A) resting and (B) delayed thallium (TL) scans and (C) BMIPPscan of patient with unstable angina. Although thallium did not show definite perfusion abnormalities,decreased BMIPP uptake was notedin lateral region.

24 Myocardial Metabolism 18 F-FDG [ 18 F] FDG cardiac PET/CT in a normal mouse (top) and in a mouse with myocardial infarction (lower). FDG cardiac uptake is uniform in the normal mouse, while there is an area of absent uptake in the anteroapical region of the mouse with myocardial infarction.

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