Other Imaging Modalities: CT, MR, Venography, Lymphangiography, Lymphoscintigraphy, Transillumination Sanjeeva P. Kalva MD, FSIR Chief, Interventional Radiology UT Southwestern Medical Center, Dallas, TX ACP Review Course
Objective To discuss the role and technique of CT Venography, MR Venography, Lymphangiography, Lymphoscintigraphy and Transillumination To review the imaging findings of common venous diseases on these imaging modalities To review the limitations of these imaging modalities
CT Venography
Direct CT Venography l and scan the area as the contrast travels up along the veins Phlebology. Sep2012, Vol. 27 Issue 6, p270-288.
Indirect CT Venography nd scan the desired area during the equilibrium phase of cont Korean J Radiol. 2011 May-Jun;12(3):327-340.
Why CT? Not operator dependent (unlike US) Better visualization of deep veins of abdomen, pelvis and chest (no problem with bowel gas or obesity) Can be combined with CT pulmonary angiography during PE evaluation Can detect other pathologies responsible for patient s symptoms
Limitations Needs IV Contrast material (Nephrotoxicity, Allergic reactions) Quality is dependent on phase of scanning Radiation
CTV vs. US for DVT of legs Patel S, Kazeeroni E. AJR 2005
Why combine CTV during CTPA for PE Evaluation
Acute DVT on CTV Direct Evidence: Complete or partial intraluminal filling defect Associated Findings: Enlarged vein Peri-venous edema Dense rim around the vein Presence of collateral veins
Chronic DVT on CTV Calcification in the vein Eccentric, juxtra-mural filling defect with irregular margin Intra-luminal strands due to partial recanalization Retracted small cord-like vein Multiple collateral veins
Acute on Chronic DVT Signs of acute DVT in combination with signs of chronic DVT
Unusual Sites of DVT on CTV
CTV Can differentiate tumor thrombus from bland thrombus
Alternative Diagnosis
CTV Pitfalls beam hardening artifacts
beam hardening artifacts
CTV Pitfalls Incomplete venous opacification
Radiation Dose during CTV Depends on the technical parameters and extent chosen. Can vary from 7 to 10mSv. Gonadal dose may range from 3 to 4mSv. Methods to decrease radiation dose should always be adopted
CTV - Summary Highly useful for detection of DVT in the abdomen, pelvis and chest Sensitivity and specificity approach those of US for lower extremity DVT Radiation dose and need for IV contrast are drawbacks
MR Venography
MRV Accepted Indications Suspected lower extremity DVT--first line if pelvic DVT Suspected upper extremity DVT--may be first line in central thorax Suspected neurologic venous sinus thrombosis (infection, dehydration)
MR Venography Physics (made ridiculously simple) + + = Magnetic field RF Pulse Receiver coil MR Image
Blood vessel
Blood vessel Black Blood MRA
White Blood MRA Blood vessel ECG gating optional
Blood vessel Time of Flight MRA
Time of Flight MRV Artery Vein
Direct Contrast MRV M. Prince, MD
Time-resolved Contrast MRV Cornfeld, AJR, 2009.
Blood Pool contrast agents: MRV (+ MRA) Leiner T, www.bloodpoolagents.us
Contraindications for MRV MRI: Pacemaker / AICD Stimulators / devices Some surgical implants and clips Gadolinium contrast: Allergic reaction Pregnancy Renal failure/nsf
Acute DVT AHA 2013; AOS.109.01-Noncoronary Vascular Imaging
Chest. 2001;120(5):1570-1576. Krinsky, G., Applied Radiology, 2004. Glockner JF. Applied Radiology 2010
Differentiate Tumor Thrombus Glockner JF. Applied Radiology 2010
Dynamic Assessment Popliteal venous entrapment
MRV Without IV Contrast
Assessment during entire cardiac cycle
MRV - Summary Indications similar to CTV - Deep veins of chest, abdomen and pelvis Differentiating tumor thrombus from bland thrombus No radiation Dynamic imaging With or without IV contrast material
Lymphangiography
Lymphangiography To assess lymphatics for leaks (chylous thorax, chylous effusion, lymphocele, lymphatic fistula which usually occur following surgery) To assess lymph nodal involvement by tumors (no more an indication now) To assess lymphedema for aplasia, hypoplasia and hyperplasia of lymphatics
Lymphangiography - Technique Journal of Medical Imaging and Radiation Oncology 54 (2010) 43 46
Journal of Medical Imaging and Radiation Oncology 54 (2010) 43 46
Journal of Medical Imaging and Radiation Oncology 54 (2010) 43 46
Intra-nodal Lymphangiography
Lymphocele following left nephrectomy
Lympho-calyceal fistula: Chyluria http://www.eurorad.org/eurorad/case.php?id=2584
Chylous Thorax
Lymph Node Metastases Can Med Assoc J. 1967 November 18; 97(21): 1282 1289.
Lymphangioma http://www.tumorlibrary.com/case/detail.jsp?image_id=4375
Lymphangiography - Summary Currently used to assess lymphatic leaks in the work up chylous effusions and during thoracic duct embolization Traditional pedal lymphangiography is replaced by intranodal lymphangiography
Lymphoscintigraphy
Lymphoscintigraphy Radioactive Technetium (Tc-99m) sulphur colloid particles or radioactive iodinated albumin are injected in to the web spaces of foot using a fine needle. These particles are taken up by lymphatics Imaging is done by using a Gamma Camera
Lymphoscintigraphy Radioactivity at inguinal nodes is measured at 30-60 minutes. Normal uptake is 0.6-1.6%. If it is less than 0.3% in 30 minutes it is diagnostic of lymphedema. If it is >2% at 30 minutes, it suggests venous edema. In 3 hours, it reaches para-aortic lymph nodes and liver. Later, thoracic duct is visualized.
Normal lymphoscinitigraphy with radioactive albumin Ann Rehabil Med. 2011 December; 35(6): 922 927.
Lymphocele Following nephrectomy
Chylothorax Indian J Nucl Med. 2012 Jul-Sep; 27(3): 208 209.
Assessment of lymphatic drainage of a tumor J Anat. 2011 June; 218(6): 652 659.
Lymphoscintigraphy Technically easier compared to lymphangiography Commonly used to detect sentinal node in breast cancer Helpful to detect lymph leak
Transillumination http://randallmathewross.com/veinlitenew/wp-content/uploads/2010/03/trans1.jpg
Transillumination Passage of light through body tissues or cavities for examination of internal structures Diaphanoscopy; Diaphanography
Surface Transillumination http://www.digas.gr/product_info.php?products_id=3222&language=en
http://www.digas.gr/product_info.php?products_id=3222&language=en
Transillumination Powered Phlebectomy Transilluminator/irrigator Resector The Vein Book edited by John J. Bergan, Nisha Bunke
Resection Tumescent injection The Vein Book edited by John J. Bergan, Nisha Bunke
Transillumination - Summary Red or orange light to see subcutaneous veins To achieve better visualization of surface veins for sclerotherapy and phlebectomy
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