Mieke Bus

14 Chapter 1 One of these techniques, Optical Coherence Tomography (OCT), can hypothetically provide the urologist with real-time intra-operative information on tumour grade and stage. In the second part of the thesis we aim to evaluate the diagnostic accuracy of OCT for grading and staging of UTUC. For this aim, both in vivo and ex vivo studies were carried out in the urological clinic. In Chapter 4 , we present a pilot study where eight patients were examined in vivo with UTUC with OCT. We analysed the images in a qualitative way by visually inspecting OCT images and dividing visible lesions in invasive and non-invasive lesions by identifying the basement membrane. Furthermore, we analysed the images in a quantitative way by means of the attenuation coefficient and we tested if the attenuation coefficient could discriminate between high-grade and low-grade lesions. In Chapter 5 we examined the ability of OCT as a tool for grading and staging of low-grade, high-grade and carcinoma in situ (CIS) lesions in the upper urinary tract. Next, we evaluated sensitivity and specificity of OCT in UTUC and established the inter-observer variability of OCT. Although OCT produces high resolu- tion cross-sectional images of the ureter, its imaging depth is limited to 1-2 mm. Therefore, tumour sizes that transcend OCT imaging depth range cannot be reliable examined using OCT. Endoluminal Ultrasound (ELUS) has an increased imaging depth range compared to OCT, but produces images of a low resolution. In Chapter 6 we examined if combined OCT and ELUS improves the capability to visualize and distinguish the anatomical layers of the human ureter and if both investigations could discriminate between normal and suspicious tissue. Therefore, we performed an OCT and ELUS measurement of the complete pyelum and ureter in five nephroureterectomy specimens. Finally, based on the results described in this thesis and on the literature, a reflection on the current position of optical diagnostics, in particular OCT, for the upper urinary tract is discussed in Chapter 7 .