CPT code 74178 identifies a comprehensive imaging service: a Computed Tomography (CT) scan of both the abdomen and pelvis. This code is used when the scan is performed in a multiphasic manner, meaning it includes imaging without intravenous (IV) contrast material, followed by subsequent imaging with IV contrast material during the same patient encounter. This dual-phase approach provides a more detailed view of the internal anatomy than a single-phase study.
Understanding the Imaging Procedure
The procedure represented by CPT 74178 uses CT technology to create cross-sectional images of the body. To begin the study, a non-contrast scan is performed first to establish a baseline view of the tissues and to detect naturally dense structures, such as calcifications or kidney stones. This initial series is important because some findings, like acute hemorrhage, can be obscured once contrast material is introduced.
The second phase involves the intravenous injection of an iodine-based contrast agent. This agent temporarily flows through the bloodstream, enhancing the visibility of organs, blood vessels, and any active pathology. The contrast material allows radiologists to assess how tissues absorb and release the agent, a process called enhancement, which can reveal characteristics of masses or tumors. The CPT code covers the entire abdomen and pelvis, including organs like the liver, pancreas, kidneys, spleen, and bladder.
The official descriptor of the code often includes the acquisition of delayed images minutes after the contrast injection. This delayed timing allows the contrast to fully excrete from the kidneys and fill the ureters and bladder. Imaging the contrast material as it moves through the urinary tract, known as CT urography, is often the primary reason this specific multiphasic study is ordered. This delayed series helps identify subtle abnormalities in the lining of the collecting system that would otherwise be invisible on earlier-phase images.
Medical Conditions Requiring This Scan
The need for both non-contrast and contrast-enhanced phases makes CPT 74178 the preferred study for a select group of complex diagnostic problems. One common indication is the workup for unexplained blood in the urine (hematuria), where a physician must rule out cancers in the urinary tract. The non-contrast images identify pre-existing stone disease, while the delayed, contrast-filled images visualize the inner lining of the kidneys, ureters, and bladder for potential tumors.
This combined study is also necessary for the characterization of indeterminate masses or lesions found on prior, less-detailed imaging. For instance, in the adrenal glands or kidneys, a mass may require a non-contrast scan to measure its density and a contrast-enhanced scan to evaluate its “wash-in” and “wash-out” properties. Analyzing these enhancement patterns can distinguish a benign lesion, such as an adrenal adenoma or a simple kidney cyst, from a more serious finding, like a malignancy.
In cases of acute trauma, the multiphasic scan is sometimes used to detect active internal bleeding, where the contrast material can be seen leaking out of a damaged blood vessel. The initial non-contrast scan provides the baseline, and the immediate post-contrast images pinpoint the exact location of the injury. The study is also frequently used in cancer staging and surveillance, as the detailed visualization helps determine the extent of disease spread and track the response to treatment.
Billing and Insurance Implications
CPT code 74178 is considered a comprehensive code, covering the technical and professional components of this complex, multi-stage examination. This single code includes the initial non-contrast acquisition, the administration of the intravenous contrast material, and the subsequent contrast-enhanced and delayed imaging series. Because it represents a dual-phase study involving IV contrast, the reimbursement rate for 74178 is typically higher than a basic CT scan performed without contrast material.
A primary concern for both providers and patients is the demonstration of medical necessity for this specific, higher-cost procedure. Insurance companies often require documentation to clearly justify why a simpler, single-phase CT was insufficient for the patient’s condition. If the medical record does not specifically state the clinical reason for needing both the non-contrast and contrast phases, the insurance claim may be denied.
CPT 74178 often requires prior authorization from the insurance provider before the procedure can be scheduled. This administrative step confirms that the payer acknowledges the medical necessity and agrees to cover the service. The patient’s actual out-of-pocket costs depend on their specific health plan, including whether they have met their annual deductible and their co-insurance percentage.