Post-Hoc Analysis of Data Received with Nuclear Medical Diagnostic in Bulgarien Patients KRASIMIRA PRODANOVA Faculty of Applied Mathemdtics and Informatics Technical University of Sofia Sofia, BULGARIA YORDANKA UZUNOVA University Hospital “Lozenets” of Faculty of Medicine Sofia University Sofia, BULGARIA Abstract— Fever of unknown origin (FUO) is a clinical condition extremely difficult to diagnose. For this purpose a number of methods are used – clinical and paraclinical, as well as medical imaging, of which only nuclear-medical diagnostic methods allow performance of full-body scanning, which avoids skipping areas, loss of time and resources. In this article we are looking for the interrelationship between two groups of factors: group 1 (body temperature; leukocytes and erythrocyte sedimentation rate (ESR) and group 2 (presence and severity of an inflammatory process). Analysis of variance (ANOVA) is used for analyzing observations of the index of accumulation that depends on the effects of the factors as patient’s temperature, leukocytes and ESR. The comparison of mean values of the statistically significant factors for the different categories of the index of accumulation and respectively activity of the inflammatory process is made. The study included 74 patients: 30 (40.54%) men aged 15 to 71 years. and 44 (59.46%) women aged 7 to 74 diagnosed in a hospital in Sofia, Bulgaria. However, ANOVA test results don’t map out which groups are different from other groups. To determine whether the mean differences between the factors are statistically significant post hoc test is used. Keywords—ANOVA, Post-hoc test, Nuclear Medical Diagnostic Received: March 9, 2021. Revised: July 23, 2021. Accepted: August 4, 2021. Published: August 20, 2021. 1. Introduction Clinics often receive patients, who have had fever for a long time, without adequate response to ongoing therapy and without an established diagnosis. Petersdorf [1] defines the term "fever of unknown origin" (FUO) as "Fever with a body temperature above 38.3° C for more than 3 weeks without a final diagnosis, despite a one-week hospital stay ". According to leading experts, a differential diagnosis should be made between FUO and four groups of diseases: infectious, malignant, autoimmune and mixed. Infections remain the most common cause of FUO [2, 3, 4]. Nuclear medicine diagnostics have many advantages over the other imaging methods. The most important of these advantages being the diagnosis of the earliest functional changes in an organism, before the development of structural-anatomical changes. Nuclear medicine also allows for whole body scanning (without any omissions of body parts in the scan), as well as saving time. Until now, using nuclear medicine diagnostics, there is some evidence in the Bulgarian scientific literature of a relationship between body temperature, leukocytes, erythrocyte sedimentation rate (ESR) and the presence and severity of the inflammatory process (IP) [5, 6], but the results based on a small samples (maximum size 54 patients). That's why we decided to look for the existence of such a relationship by applying the diagnostic capacity of nuclear medicine based on the data from random sample of 74 patients. Analysis of variance (ANOVA) is one of the most frequently used statistical methods in medical research [7]. Analysis of variance (ANOVA) is used for analyzing observations of the index of accumulation (in four groups) that depends on the effects of the factors as patient’s body temperature, leukocytes and erythrocyte sedimentation rate (ESR). The comparison of mean values of the statistically significant factors for the four categories of the index of accumulation and respectively activity of the inflammatory process will make it possible to apply the adequate treatment targeted at personalized medicine. To determine whether the mean differences between the factors values are statistically significant post hoc test of Kruskal-Wallis is used. 2. Materials and Methods The data are received from a random sample of 74 patients with fever of unknown origin (FUO): 30 (40.54%) men aged 15 to 71 years, and 44 (59.46%) women aged 7 to 74, all diagnosed in a hospital of ministry of interior in Sofia. In 52,70% (39 persons) there was no initial working diagnosis and therefore they were united in a first subgroup - only fever, while 47,30% (35 persons) had an initial working diagnosis and were grouped into 9 subgroups, respectively: pyelonephritis - 8 (2 with + 6 without a classic clinical presentation (CCP)); post-operative complications - 6 (4 with + 2 without), sepsis - 5 (2 with + 3 without CCP); Crohn's disease - 5 (1 with + 4 without CCP); abscess - 4 (1 with + 3 without CCP); bronchopneumonia - 3 without CCP; pleurisy - 2 without CCP; alopecia- 2 without CCP; Lyme disease - 2 without CCP. The objectives of the nuclear medical diagnostic study are: First: Evaluation of the quality of the 99m Tc-HMPAO leukocyte tagging technique used. For this purpose, an "efficiency of tagging" (ET) of the leukocytes is used and is equal to: (Asample) / [Asample + Aaspirated Plasma], where Asample is activity of the sample. WSEAS TRANSACTIONS on BIOLOGY and BIOMEDICINE DOI: 10.37394/23208.2021.18.16 Krasimira Prodanova, Yordanka Uzunova E-ISSN: 2224-2902 136 Volume 18, 2021