THE INFORMATIVE VALUE OF MAGNETIC RESONANCE IMAGING IN THE DIAGNOSIS OF RECTAL TUMOR INVOLVEMENT AGAINST THE BACKGROUND OF COMBINED TREATMENT

The aim of the study is to prove the informative value of magnetic resonance imaging in the diagnosis of rectal tumor involvement against the background of combined treatment for the patients (chemotherapy + radiation therapy) on the basis of the AI "Republican Oncological Dispensary", Cheboksary. All patients underwent magnetic resonance imaging on Elekta Synergy linear accelerator with a multi-leaf collimator, an integrated XVI X-ray volumetric imaging system and iViewGT portal imaging system, Mosaiq information and control system. Statistical processing was performed using standard methods of medical statistics using the SPSS Statistics package (version 17.0), arithmetic mean (M), standard deviation from the general mean age, mean value errors (m), Student's t-test were also calculated. Magnetic resonance imaging diagnostics made it possible to identify and dynamically control the change in the tumor involvement of the rectum against the background of the treatment: a change in the localization of the tumor in different parts of the rectum, a change in localization depending on the distance from the anal margin, a change in the thickness of the tumor wall, a change in the size and number of lymph nodes. Extramural venous invasion (EMVI), marginal resection boundary (CRM) of the tumor and invasion into surrounding tissues after surgical intervention were evaluated. This article examines the incidence of rectal cancer depending on age, gender, complaints, oncological history, risk factors contributing to the development of this pathology, as well as the presence of concomitant diseases that aggravate treatment. According to the results of the study, rectal cancer is revealed to be most often found in people aged 60–70, while men are most susceptible to the disease. According to histomorphological data, adenocarcinoma prevailed in 94 persons. Rectal cancer before and after chemoradiotherapy, according to magnetic resonance imaging (MRI) findings, prevailed in the rectal lower ampulla (before chemoradiotherapy – in 51 persons, after chemoradiotherapy – in 48), while the malignant neoplasm was at the distance of 21-30 mm from the anal margin in 27 persons, with the average wall thickness of 21.5 mm according to MRI findings before chemoradiotherapy and 13.9 mm after chemoradiotherapy. The difference in the average wall thickness according to the findings of two MRI studies was 7.61 mm (33.3%), which indicates the effectiveness of chemoradiotherapy.