Potential role of a hybrid intraoperative probe based on OCT and positron detection for ovarian cancer detection and characterization

Abstract

Ovarian cancer has the lowest survival rate of the gynecologic cancers because it is predominantly diagnosed in the late stages due to the lack of reliable symptoms and efficacious screening techniques. A novel hybrid intraoperative probe has been developed and evaluated for its potential role in detecting and characterizing ovarian tissue. The hybrid intraoperative dual-modality device consists of multiple scintillating fibers and an optical coherence tomography imaging probe for simultaneously mapping the local activities of (18)F-FDG uptake and imaging of local morphological changes of the ovary. Ten patients were recruited to the study and a total of 18 normal, abnormal and malignant ovaries were evaluated ex vivo using this device. Positron count rates of 7.5/8.8-fold higher were found between malignant and abnormal/normal ovaries. OCT imaging of malignant and abnormal ovaries revealed many detailed morphologic features that could be potentially valuable for evaluating local regions with high metabolic activities and detecting early malignant changes in the ovary. These initial results have demonstrated that our novel hybrid imager has great potential for ovarian cancer detection and characterization during minimally invasive endoscopic procedures.

Keywords: (170.3880) Medical and biological imaging; (170.3890) Medical optics instrumentation; (170.4440) ObGyn; (170.4500) Optical Coherence Tomography.

Fig. 1

(a) Schematic of swept-source OCT system. (b) Schematic of positron detection system. (c) Side view of the hybrid probe integrating OCT fiber and nuclear detectors. (d) Tissue surface view of the hybrid probe; (e) Photograph of the hybrid probe. (f) Experimental setup; (g) Co-registration scheme of surface positron distribution map and a sequence of OCT images.

Fig. 2

One set of images obtained from the left ovary of normal patient #5. (a) Positron distribution map. (b) One representative OCT image obtained from a sequence of co-registered OCT images. (c) Corresponding 40× H&E histology. The OCT image size is 2 mm (depth) × 5 mm (lateral) (height × width); the histology size is 2 mm × 2.6 mm (height × width); the white scale bar is 0.5 mm.

Fig. 3

One set of images obtained from the right ovary (abnormal) of patient #10. (a) Positron distribution map. (b) One representative OCT image obtained from a sequence of co-registered OCT images. (c) Corresponding 40× H&E histology. Pink arrow, collagen; red oval arrow, congested vessels; yellow diamond arrow, dermoid tumor. The OCT image size is 2 mm (depth) × 5 mm (lateral) (height × width); the histology size is 2mm × 2.6 mm (height × width); the white scale bar is 0.5 mm.

Fig. 4

One set of images obtained from the left ovary of abnormal patient #9. (a) Positron count rates from different locations of left ovary. (b) Positron distribution map from the location with highest count rate. (c) One representative OCT image obtained from a sequence of co-registered OCT images. (d) Corresponding 40× H&E histology. Red circle, lymphocytes. The OCT image size is 2 mm (depth) × 5 mm (lateral) (height × width); the histology size is 2mm × 2.6 mm (height × width); the white scale bar is 0.5 mm.

Fig. 5

Two sets of images obtained from the left ovary of patient #7 with malignant ovarian cancers. (a), (b) and (c) are from one side of the left ovary; (d), (e) and (f) are from the other side of the left ovary. (a) and (d): Positron distribution maps. (b) and (e) Representative OCT images obtained from a sequence of co-registered OCT images. (c) and (f) Corresponding 40× H&E histology. Pink arrow, collagen; purple stealth arrow, tumor nodule. The OCT image size is 2 mm (depth) × 5 mm (lateral) (height × width); the histology size is 2mm × 2.6 mm (height × width); the white scale bar is 0.5 mm.

Fig. 6

One set of images obtained from the right ovary of patient #7 with ovarian cancers. (a) Positron distribution map. (b) One representative OCT image obtained from a sequence of co-registered OCT images. (c) Corresponding 40× H&E histology. Red circle, corpus albicans; purple stealth arrow, tumor. The OCT image size is 2 mm (depth) × 5 mm (lateral) (height × width); the histology size is 2mm × 2.6 mm (height × width); the white scale bar is 0.5 mm.

Fig. 7

Two sets of images obtained from the right ovary of patient #8 with ovarian cancers. (a), (b) and (c) are from one location; (d), (e) and (f) are from another location. (a) and (d) Positron distribution maps. (b) and (e) Representative OCT images obtained from a sequence of co-registered OCT images. (c) and (f) Corresponding 40× H&E histology. Pink arrow, collagen bundle. The OCT image size is 2 mm (depth) × 5 mm (lateral) (height × width); the histology size is 2mm × 2.6 mm (height × width); the white scale bar is 0.5 mm.