In this section, we present an overview of our clinical work on eNose applications. Up till now, we have been involved in research on diagnosing tuberculosis, head and neck cancer, breast cancer, lung cancer, COPD, angina pectoris, heart failure and CRPS by exhaled breath analysis (Aeonose). Headspace analysis is being applied for investiging Metritis and Mastitis (veterianary), prostate cancer and colon cancer.
The results are reported by a scatterplot placing all measurement on a map where a value around the value one indicating positive testing and zero for negative testing. In most cases the PPV (positive predicting value) and NPV (negative predictive value) are reported as well as the ROC-curve to display all combinations of sensitivity and specificity the device can reach.
Tuberculosis (TB), a highly infectious airborne disease, remains a major global health problem. Many of the newly developed diagnostic techniques are not suited for operation in the highly-endemic often low-income countries. A sensitive, fast, easy-to-operate and low-cost method is urgently needed. In Bangladesh, we performed a Proof of Principle Study (15 patients and 15 healthy controls) and a Validation Study (194 participants of which 148 patients) to assess the diagnostic value of an implementation of a generic electronic nose (Aerekaprobe) using exhaled air to detect active tuberculosis. Aerekaprobe measurements were validated using traditional sputum smear microscopy and culture on Löwenstein-Jensen media. With the documented average sensitivity of 86% and specificity of 93% for two different studies, the Aerekaprobe appears to provide a solid method for TB detection. Receiver operating characteristic (ROC) curves show a clear differentiation between TB and non-TB cases. Different types of control groups were included to compensate for e.g. socio-economical differences and general health issues. The fast time-to-result of the battery operated Aerekaprobe could enable proactive searches for new TB cases, without the need for highly-skilled operators. The results of this study have been published in ‘Tuberculosis’. Currently studies are ongoing in Kenya (Dr. Rinn Song, Harvard University) and Indonesia (Dr. A. Morita Saktiawati, University of Groningen). Additional studies are being scheduled in South Africa and Paraguay.
At the Maastricht UMC+, the group of dr. Kross has conducted research on diagnosing head and neck cancer by analyzing exhaled breath. An Aerekaprobe was used for this purpose, as the Aeonose had not been developed yet. The major advantage of an electronic nose in this specific application is its non-invasiveness as traditionally, a biopsy has to be performed. The results of this study have been published to the scientific journal Laryngoscope. An efficacy study using Aeonoses has been started recently.
Detecting and identifying pathogenic bacteria
By analyzing the gases in the headspace of media containing pathogenic bacteria, several types of these bacteria can be identified quickly. This opens-up a range of applications varying from a point-of-care unit for blood and urine analysis outside the traditional laboratory environment to veterinary and food applications. A paper on this new technique has been published in Eur J Clin Microbiol Infectious Diseases and all the work on this subject has been published in the Thesis of Marcel Bruins.