A computed tomography (CT) scan uses an iodinated contrast medium, usually introduced through an intravenous line, to enhance the visibility of tissues and organs. This contrast agent improves the diagnostic quality of the scan but must be processed and eliminated from the body afterward. The steps taken immediately following the procedure focus on helping the body flush out this agent and monitoring for any potential delayed side effects.
Expediting Contrast Agent Elimination
The iodinated contrast material is water-soluble, and the kidneys are responsible for its rapid removal from the bloodstream. For most healthy individuals, the majority of the contrast is filtered out and excreted through the urine within 24 hours. The most effective action a patient can take to assist this process is to significantly increase fluid intake in the hours following the procedure.
Hydration helps dilute the contrast, facilitating the kidneys’ ability to filter it efficiently. Healthcare providers commonly advise drinking eight to ten glasses of water, or approximately two to three liters, over the first 24 hours after the scan. This increased fluid volume leads to an increase in urination, which is the mechanism for clearing the contrast from the body.
Identifying and Managing Post-Scan Reactions
The injection of contrast material can cause common and temporary sensations, which are not signs of an adverse reaction. Many people experience a warm, flushing sensation, a metallic taste in the mouth, or brief nausea immediately following the injection. These effects are physiological responses that typically subside within minutes without requiring medical intervention.
It is important to differentiate these expected sensations from true allergic or adverse reactions, which can be immediate or delayed. Immediate reactions occur within minutes to an hour of the injection. They can range from mild symptoms like hives and itching to severe reactions such as difficulty breathing, swelling of the face or throat, or a sudden drop in blood pressure.
Facility staff usually monitors patients for a short period after the scan to manage immediate reactions promptly. A delayed reaction can manifest hours or days after the procedure, typically presenting as a skin rash. If any concerning symptoms, such as widespread rash, persistent vomiting, or difficulty breathing, develop after leaving the facility, the patient should immediately contact the imaging center, their ordering physician, or seek emergency medical attention. Severe reactions are rare, but prompt recognition and treatment are necessary for patient safety.
Resuming Medications and Daily Activities
For most individuals, daily activities can be resumed immediately, and there are typically no restrictions on driving unless a sedative was administered. A regular diet can also be maintained unless specific instructions were provided. Patients who take the common diabetes medication Metformin require specific guidance due to its interaction with kidney function.
Metformin is processed by the kidneys. If the contrast material causes a temporary change in kidney function, there is a small risk of the drug accumulating in the body, which can lead to lactic acidosis. Patients taking Metformin are often advised to temporarily withhold the medication starting at the time of the scan.
The drug should only be restarted after a 48-hour waiting period and subsequent blood tests confirm stable kidney function. Patients must follow the specific instructions provided by their ordering physician, who manages the restart of the medication based on kidney function tests.
Understanding How You Receive Your Results
After the CT scan is completed, the images are sent to a specialized physician known as a radiologist. The radiologist analyzes the images and generates a formal, written report detailing the findings and interpretations. This process takes time and is separate from the actual scanning procedure.
The radiologist’s report is then transmitted directly to the physician who ordered the CT scan. The typical turnaround time for this report in an outpatient setting is often between 24 and 72 hours, though urgent findings are communicated rapidly. It is the responsibility of the ordering physician, not the CT facility, to integrate the radiologist’s findings with the patient’s medical history and communicate the results and treatment plan to the patient.