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KEY FACTS
Terminology
Imaging
TERMINOLOGY
Tumor Angiogenesis
- Tumor development requires adequate system of blood vessels supplying adequate nutrition and removal of waste products
- At earliest stages of neoangiogenesis, tumors recruit vessels from host, most of which come from venous capillary network in form of vascular sinusoids
- At same time, tumors produce variety of endothelial growth factors, which initiate new tumor development within tumor and surrounding areas
- At early stages, tumors have hypervascular periphery with hyperemic rim of tissue
- As tumors progress, central areas may become ischemic due to inability to develop adequate vascular networks
- Later, ischemic central areas may undergo necrosis
Tumor Vessel Morphology
- Tumor vascular networks usually demonstrate abnormal branching patterns without typical hierarchical order of blood vessel branching seen in normal tissues
- Tumor neovascularity can also be differentiated from normal tissues by irregular sizes of vessels and presence of arteriovenous shunts
- On more microscopic level, tumor blood vessels are characterized by paucity of smooth muscle within vessel walls, making them more pliable and less pressure resistant
- Morphologic appearance of tumor vessels may not allow direct assessment of function of tumor microcirculation or differentiation of benign from malignant tumors due to 20-80% of vascular network being perfused within any given tumor at particular time, while large portions of tumor vascular bed remain dormant
- This leads to significant variations in tumor blood flow velocities and tumor vascularity between different areas within same tumor
Factors Affecting Tumor Perfusion
- Disorganized vascular networks
- Substantial deviations in tumor vessel size
- Increased interstitial pressure
- Increased interstitial pressure within tumors considered one of most important factors affecting blood flow within tumors
- Several factors result in increased interstitial pressure within tumors
- Increased permeability of tumor vessels
- Deficiencies on lymphatic drainages, often blocked by proliferating tumors and metastatic deposits
- Rapid proliferation of tumor cells in relatively confined spaces
IMAGING
Liver Masses
Renal Masses
Breast Masses
Thyroid Masses
Ovarian Masses
Selected References
- Dietrich CF et al: How to perform contrast-enhanced ultrasound (CEUS). Ultrasound Int Open. 4(1):E2-E15, 2018
- Barr RG et al: Evaluation of indeterminate renal masses with contrast-enhanced US: a diagnostic performance study. Radiology. 271(1):133-42, 2014
- Claudon M et al: Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the liver--update 2012: a WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS. Ultraschall Med. 34(1):11-29, 2013
- Fleischer AC et al: Advances in sonographic detection of ovarian cancer: depiction of tumor neovascularity with microbubbles. AJR Am J Roentgenol. 194(2):343-8, 2010
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References
Tables
Tables
KEY FACTS
Terminology
Imaging
TERMINOLOGY
Tumor Angiogenesis
- Tumor development requires adequate system of blood vessels supplying adequate nutrition and removal of waste products
- At earliest stages of neoangiogenesis, tumors recruit vessels from host, most of which come from venous capillary network in form of vascular sinusoids
- At same time, tumors produce variety of endothelial growth factors, which initiate new tumor development within tumor and surrounding areas
- At early stages, tumors have hypervascular periphery with hyperemic rim of tissue
- As tumors progress, central areas may become ischemic due to inability to develop adequate vascular networks
- Later, ischemic central areas may undergo necrosis
Tumor Vessel Morphology
- Tumor vascular networks usually demonstrate abnormal branching patterns without typical hierarchical order of blood vessel branching seen in normal tissues
- Tumor neovascularity can also be differentiated from normal tissues by irregular sizes of vessels and presence of arteriovenous shunts
- On more microscopic level, tumor blood vessels are characterized by paucity of smooth muscle within vessel walls, making them more pliable and less pressure resistant
- Morphologic appearance of tumor vessels may not allow direct assessment of function of tumor microcirculation or differentiation of benign from malignant tumors due to 20-80% of vascular network being perfused within any given tumor at particular time, while large portions of tumor vascular bed remain dormant
- This leads to significant variations in tumor blood flow velocities and tumor vascularity between different areas within same tumor
Factors Affecting Tumor Perfusion
- Disorganized vascular networks
- Substantial deviations in tumor vessel size
- Increased interstitial pressure
- Increased interstitial pressure within tumors considered one of most important factors affecting blood flow within tumors
- Several factors result in increased interstitial pressure within tumors
- Increased permeability of tumor vessels
- Deficiencies on lymphatic drainages, often blocked by proliferating tumors and metastatic deposits
- Rapid proliferation of tumor cells in relatively confined spaces
IMAGING
Liver Masses
Renal Masses
Breast Masses
Thyroid Masses
Ovarian Masses
Selected References
- Dietrich CF et al: How to perform contrast-enhanced ultrasound (CEUS). Ultrasound Int Open. 4(1):E2-E15, 2018
- Barr RG et al: Evaluation of indeterminate renal masses with contrast-enhanced US: a diagnostic performance study. Radiology. 271(1):133-42, 2014
- Claudon M et al: Guidelines and good clinical practice recommendations for contrast enhanced ultrasound (CEUS) in the liver--update 2012: a WFUMB-EFSUMB initiative in cooperation with representatives of AFSUMB, AIUM, ASUM, FLAUS and ICUS. Ultraschall Med. 34(1):11-29, 2013
- Fleischer AC et al: Advances in sonographic detection of ovarian cancer: depiction of tumor neovascularity with microbubbles. AJR Am J Roentgenol. 194(2):343-8, 2010
