Contrast enhanced ultrasound imaging can predict vascular-targeted photodynamic therapy induced tumor necrosis in small animals

• Published in: Photodiagnosis and photodynamic therapy Vol. 20; pp. 165 - 168
• Main Authors: Cornelis, F.H., Kim, K., Durack, J.C., Jebiwott, S., Scherz, A., Srimathveeravalli, G., Coleman, J.A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01-12-2017
• Subjects: Animals; Contrast-enhanced ultrasound; Disease Models, Animal; Mice; Mice, Inbred BALB C; Neoplasms - diagnostic imaging; Neoplasms - drug therapy; Neoplasms - pathology; Photochemotherapy - methods; Tumor; Ultrasonography - methods; Vascular targeted photodynamic therapy; Contrast-enhanced ultrasound; Vascular targeted photodynamic therapy; Tumor
• ISSN: 1572-1000; 1873-1597
• DOI: 10.1016/j.pdpdt.2017.09.002

•CEUS images demonstrated non-enhancing zones 24 hours after VTP.•CEUS findings correlated with Pathology after VTP.•CEUS allows accurate monitoring of VTP induced tumor necrosis in a small animal model.
To evaluate the accuracy of contrast-enhanced ultrasound (CEUS) for monitoring tumor necrosis following WST-11 vascular targeted photodynamic therapy (VTP) using imaging-pathology correlation.
Renal adenocarcinoma cells were injected into the hindlimb of 13 BalB/c mice resulting in tumors ranging from 9.8 to 194.3mm3. US guidance was used to place a laser fiber into the tumor, and VTP was performed. CEUS was performed prior to animal sacrifice, 24h post-VTP. Whole tumors were extracted for histopathologic analysis using H&E and TUNEL staining. Pathology samples corresponding to the CEUS imaging plane were prepared in order to compare the size and extents of tumor necrosis.
Tumor necrosis following VTP appeared as a central region of non-enhancement on CEUS, while viable tumor appeared as patchy regions of enhancement in the tumor periphery. The region of tumor necrosis measured in mean 66% and 64.8% of total tumor area on CEUS and pathology respectively (p=0.2). The size and location of the necrosis on CEUS images and pathology samples were found correlative with no inter-observer difference (weighted kappa of 0.771 and 0.823, respectively).
CEUS allows accurate monitoring of VTP induced tumor necrosis in a small animal model.