Nuclear Medicine Q & A
Q: The following is a report of a procedure for a patient who presented to the nuclear medicine department with a possible partial obstruction of the left ureteropelvic junction. What is the appropriate coding of this procedure?
Scan Technique: The patient was injected with 10 mCi of Tc-99m-MAG3 and sequential flow and delayed images were obtained. At 20 minutes following radionuclide injection, the patient received 20 mg of furosemide IV to determine whether a physiologically significant obstruction is present.
Scan Findings: The flow part of the study shows perfusion to both kidneys consistent with function. The relative function portion of the study shows the left kidney contributes 40% of total function, the right 60%, indicating minimal impairment on the left. The absolute function on the right is normal, but mildly reduced renal function is noted on the left.
In the imaging portion of the study the early views show a photopenic region centrally in the region of the intrarenal collecting system on the left indicating mild hydronephrosis. This fills in promptly, persists after the administration of diuretic and also persists in the delayed post-void upright images. This indicates obstruction of the left ureteropelvic junction. The images on the right are normal excluding obstruction.
The renograms derived from the imaging study show a normal pattern of spontaneous washout on the right. The left renogram is abnormal with a rising pattern until the administration of diuretic, when there is a blunted response with a half-washout time of 22 minutes (<15 minutes normal), confirming significant partial obstruction.
Impression
- Renal blood flow consistent with function.
- Asymmetrical renal function with the right kidney contributing 60% of total function.
- The left kidney has minimal impairment of renal function.
- No obstruction on the right.
- Scan evidence significant partial obstruction on the left.
A: The appropriate CPT® coding of the above procedure would be 78708 [Kidney imaging with vascular flow and function; single study, with pharmacological intervention (eg, angiotensin converting enzyme inhibitor and/or diuretic)]. This indicates that only a single vascular flow and function study was performed using a diuretic.
It also is appropriate to code separately for the radiopharmaceutical and diuretic used to perform the study. For Medicare patients, code 10 units of HCPCS code Q3005 (Supply of radiopharmaceutical diagnostic imaging agent, Tc99m, mertiatide, per millicurie) for the 10 mCi of MAG 3, and 1 unit of J1940 (Injection, furosemide, up to 20 mg) for the 20 mg of furosemide. Check with other third-party payers for their guidelines on the coding of supplies. Some payers may require the use of CPT® code 78990 (Provision of diagnostic radiopharmaceuticals) for billing of radiopharmaceutical supplies. The physician work for intravenous injection of radiopharmaceuticals and pharmacologic agents is included in the nuclear medicine procedures and should not be coded separately.
Discussion
There are a number of codes that describe kidney imaging with vascular flow and function. The selection of the appropriate code for the procedure depends on whether or not pharmacologic intervention is used, and whether the procedure consists of a single study or multiple studies. In the above scenario, a single imaging study with pharmacologic intervention using the diuretic furesomide is performed as described by CPT® code 78708. This CPT® code is most often used in diuretic (furosemide) studies for obstruction.
Code 78707 (single study without pharmacological intervention) describes an imaging renogram study that provides information about perfusion and relative renal function. This study without pharmacologic stimulation is commonly used as a renal transplant study to assess perfusion and function of a transplanted kidney; it is sometimes used to determine whether one kidney provides more function than the other.
Code 78708 (single study with pharmacological intervention) also provides information about perfusion and relative renal function; however, this study is performed with pharmacologic stimulation, e.g., a diuretic or an angiotensin converting enzyme (ACE) inhibitor. This code describes one of two kidney imaging with vascular flow and function studies performed with pharmacological intervention.
While code 78708 describes a single study performed with pharmacologic stimulation, code 78709 (multiple studies, with pharmacological intervention) is used to describe two perfusion and imaging function studies done sequentially. Code 78709 is effectively a combination of 78707 and 78708, as two flow studies and two function studies are performed with an ACE inhibitor to determine the effect of that stimulation (e.g., with and without Captopril, an ACE inhibitor). When two flow and function studies are performed either on the same day or on two separate days, 78709 should be coded only once. It is of note that the standard protocols for 78709 commonly include the use of diuretics also (hence the term diuretic study is not specific, and not used solely in 78708 studies).
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