Background: Accurate assessment of intravascular volume status is critical in intensive care management. Conventional methods may have limitations in precision and availability. Computed tomography (CT) offers the opportunity to measure the diameter and cross-sectional area of the inferior vena cava (IVC), potentially providing an alternative tool for fluid evaluation. Methods: This diagnostic investigation was conducted in the Internal Medicine Intensive Care Unit between 2022 and 2023. A total of 105 patients diagnosed with pneumonia were enrolled. Standardized CT imaging was performed for each participant, with measurements obtained at predetermined thoracic anatomical levels. Clinical indicators of fluid status, including pleural effusion and brain natriuretic peptide (BNP) levels, were recorded for comparison. Results: CT-based measurements of IVC diameter and area demonstrated statistically significant correlations with conventional indicators of intravascular volume status. Both pleural effusion and BNP levels were closely associated with the imaging parameters, thereby confirming their clinical relevance. Conclusions: CT measurements of the IVC provide a reliable, non-invasive approach to assessing intravascular volume in critically ill patients. This method holds promise for improving fluid management strategies in intensive care practice, offering an effective adjunct to traditional evaluation techniques.