Volume 135, Issue 4, Pages 1069-1078 (October 2008) Spectroscopic Microvascular Blood Detection From the Endoscopically Normal Colonic Mucosa: Biomarker for Neoplasia Risk  Hemant K. Roy, Andrew Gomes, Vladimir Turzhitsky, Michael J. Goldberg, Jeremy Rogers, Sarah Ruderman, Kim L. Young, Alex Kromine, Randall E. Brand, Mohammed Jameel, Parmede Vakil, Nahla Hasabou, Vadim Backman  Gastroenterology  Volume 135, Issue 4, Pages 1069-1078 (October 2008) DOI: 10.1053/j.gastro.2008.06.046 Copyright © 2008 AGA Institute Terms and Conditions

Figure 1 (A) Schematic diagram (frontal view) of the endoscopically compatible polarization-gating spectroscopy fiberoptic probe. (B and C) Photographs of probe. Gastroenterology 2008 135, 1069-1078DOI: (10.1053/j.gastro.2008.06.046) Copyright © 2008 AGA Institute Terms and Conditions

Figure 2 Polarization-gating spectroscopy probe accurately measured Hb concentrations over a large range of physiologic values (tissue phantom study). The solid lines represent linear approximations. Measured Hb concentrations showed excellent correlations with actual Hb contents with an r2 value of 0.99 for all depths. The root mean squared errors from the probing depths of (A) approximately 100 μm, (B) approximately 130 μm, and (C) approximately 170 μm were 0.33 g/L, 0.36 g/L, and 1.20 g/L, respectively. Gastroenterology 2008 135, 1069-1078DOI: (10.1053/j.gastro.2008.06.046) Copyright © 2008 AGA Institute Terms and Conditions

Figure 3 Probe operation characteristics have a negligible effect on the blood content measurement using the fiberoptic probe. (A) Probe pressure. (B) Probe angle. (C) Colon distension. Gastroenterology 2008 135, 1069-1078DOI: (10.1053/j.gastro.2008.06.046) Copyright © 2008 AGA Institute Terms and Conditions

Figure 4 Determination of interrogation depth for hemoglobin in the endoscopically normal mucosa that allowed optimal discrimination of patients harboring neoplasia (∼30 cm away from adenoma) from those who were neoplasia-free. Comparison of (A) total Hb and (B) DHb contents were assessed within 3 different depths of approximately 100 μm, approximately 130 μm, and approximately 170 μm, respectively. The approximately 100-μm depth had provided the greatest distinction with progressively lower effect sizes at 130 μm, and approximately 170 μm, respectively. □, No neoplasia; , adenoma. Gastroenterology 2008 135, 1069-1078DOI: (10.1053/j.gastro.2008.06.046) Copyright © 2008 AGA Institute Terms and Conditions

Figure 5 Microvascular blood content (depth, ∼100 μm) varies with distance from adenomas. (A) Total Hb and (B) DHb mirrored the distance from the lesion. Gastroenterology 2008 135, 1069-1078DOI: (10.1053/j.gastro.2008.06.046) Copyright © 2008 AGA Institute Terms and Conditions

Figure 6 Polyp size and histology impact on microvascular blood content (measured at ∼100 μm depth). (A) EIBS in the uninvolved mucosa (∼10 cm away from the lesion) was greater in larger (advanced) adenomas vs nonadvanced adenomas. (B) Total Hb (i) and DHb (ii) from polyp tissue paralleled uninvolved mucosal data. (C) Hyperplastic polyps did not engender EIBS in uninvolved mucosa, but was associated with increased blood content in polyp tissue: (i) Total Hb, (ii) DHb. Gastroenterology 2008 135, 1069-1078DOI: (10.1053/j.gastro.2008.06.046) Copyright © 2008 AGA Institute Terms and Conditions