A computed tomography (CT) scan of the lungs is a specialized X-ray procedure that uses computer processing to create cross-sectional images of the chest cavity. This process allows physicians to view the lung tissue, blood vessels, and airways with exceptional clarity. CT scans help diagnose conditions such as pneumonia, lung nodules, or pulmonary embolism. While the overall appointment involves several steps, the actual time spent acquiring images is brief, often lasting less than five minutes.
The Actual Time in the Scanner
The active scanning process is fast due to modern technology. For a standard lung CT, image acquisition often takes between 30 seconds and two minutes. During this time, the patient lies still on a motorized table that slides quickly through the doughnut-shaped CT machine, or gantry.
The speed is achieved using the helical or spiral scanning technique, where the X-ray tube rotates continuously while the table moves. Low-Dose CT (LDCT), used for lung cancer screening, is particularly rapid and involves a lower radiation dose. High-Resolution CT (HRCT) may take slightly longer for detailed evaluation of lung texture, but is still completed in just a few minutes. To ensure sharp images, the technologist instructs the patient to hold their breath for 10 to 15 seconds during the critical part of the scan.
Preparation Before the Scan
Preparation steps significantly contribute to the overall time spent at the facility. Before scanning, patients must complete administrative processes, including check-in, confirming insurance, and signing consent forms, which typically takes 10 to 15 minutes. Patients are then asked to change into a hospital gown and remove metallic objects, such as jewelry or zippers, which can interfere with the X-ray beams.
A major variable in preparation time is the use of intravenous (IV) contrast dye. This substance contains iodine and enhances the visibility of blood vessels and certain tissues. If contrast is required, a technologist inserts an IV line into a vein in the arm. The technologist then injects the contrast and waits for it to circulate before scanning begins, adding an extra 10 to 15 minutes to the preparation phase.
Total Appointment Time and Receiving Results
The total time a patient should plan to be at the imaging facility, from arrival to departure, is typically between 45 and 90 minutes. This range accounts for check-in, changing, positioning on the table, the rapid scanning time, and any post-scan procedures. If IV contrast was administered, the patient may be asked to wait up to 30 minutes following the scan to ensure there is no immediate adverse reaction to the dye.
Patients will not receive the final diagnostic report immediately after the scan. The images must first be reviewed and interpreted by a specialized physician known as a radiologist. The radiologist generates a detailed report, which is sent to the ordering physician. The typical turnaround time for this report is 24 to 48 hours, depending on the facility’s volume and the urgency of the findings. The ordering physician will then discuss the results with the patient.