Volumetric analysis of occipital lobe structures in hypertensive patients using magnetic resonance imaging

Blood pressure is determined by the lumen width and wall structure of arterioles. This pressure increases as a result of narrowing of the arteriole diameter and causes hypertension (HT). Cardiologists in our country regulate their diagnosis and treatment using the guidelines of the European Society of Cardiology (ESC). According to the current guideline published by this society in 2024, HT is diagnosed when systolic blood pressure is ≥140 mmHg or diastolic blood pressure is ≥90 mmHg. The use of antihypertensive drugs alone is also sufficient for the diagnosis of HT. Hypertension has systemic effects and can result in severe complications if not managed appropriately. It is also one of the most important risk factors for cerebrovascular disease. This condition can lead to changes in the central nervous system. There are many emergencies associated with HT and one of them is encephalopathy. The condition, generally observed in the posterior part of the brain and reversible with timely treatment, is called posterior reversible encephalopathy syndrome (PRES). It occurs when the autoregulatory limit is rapidly exceeded. It causes an edema image in the occipital lobe (OL) and sometimes in a part of the parietal lobe on Magnetic Resonance Imaging. Considering the effect of PRES on OL volume, the reason for our study was to observe the effect of HT on the same region. In this study, in which 119 people in the control group and 120 people in the patient group were evaluated, three different age ranges, 30-40, 41-50 and 51-60, were created in order to prevent atrophy due to aging from overshadowing the HT effect in the brain. To observe the morphological effects on OL, volBrain, an automatic segmentation program, was used to analyse 1 mm thick T1-weighted images. It was observed that HT affected the OL and its substructures in females compared to males, leading to a decrease in the volume of the cuneus, especially in the 30-40 and 51-60 age ranges. Cortical thickness was analysed especially to assess cognitive status and no significant differences were observed when compared according to gender and age ranges. To minimise the risk of being influenced by personal factors, the data were also evaluated by standardising the volumes of the structures according to intracranial volume. Considering the effect of PRES on the OL volume, observing the effect of HT on the same region formed the rationale for our study. Keywords:Occipital Lobe, Hypertension, Volume, Cuneus, volBrain, Magnetic Resonance Imaging