Radiology Coding Alert

CPT Code 93880 describes the gold standard for diagnostic cerebrovascular ultrasound, and coders must understand when to assign it as opposed to several related codes to optimize timely reimbursement.

Although there are various codes within the Non-invasive Vascular Diagnostic Studies section of CPT that describe cerebrovascular arterial studies, 93880 (duplex scan of extracranial arteries; complete bilateral study) far and away describes the test of choice, explains Richard Brebner, BS, RDMS, RDCS, RVT, vice president and technical director for Ultrasound Services Inc., which provides portable diagnostic ultrasound services in Pennsylvania, Delaware and New Jersey. It is ordered when a physician suspects an arterial occlusion, stenosis or similar condition. Well use ultrasound to look at the carotid artery and provide an initial evaluation concerning the condition of the vessel.

The ultrasound study defined in 93880 focuses on vessels positioned on the outside of the skull (i.e., extracranial), according to Rob Levin, CHBME, chief operating officer for Billing Solutions Inc., in Newtown, Pa., which provides medical billing services to
Ultrasound Services. A Doppler study uses sound waves to measure blood flow, he explains. However, a duplex scan as described in CPT 93880 adds an anatomical component to the flow measurement, which allows a sonographer to see plaque buildup that is causing a partial or complete blockage, while listening to the blood flow.

Brebner notes that code 93882 ( unilateral or limited study) is most frequently assigned when a follow-up study is ordered not as the initial diagnostic test. When a cerebrovascular problem is initially suspected, the bilateral study typically is ordered, because the requesting physician will want a full and complete study of both carotid arteries. Once the suspected blockage is found and treated, a limited study will likely be ordered for that specific site to ascertain the success of the procedure.

Coding the Exam of Vessels in the Skull

One of the challenges sonographers encounter during cerebrovascular studies occurs when the patients blockage cant be located extracranially. Code 93880 describes scans covering the clavicle to the foramen where the vessels enter the skull, Brebner explains. Beyond that point, the major arteries lie beneath the skull, which does not allow ultrasound investigation in the same manner as the extracranial circulation studies. The terminal branches cant be visualized through the cranium during the scan, he says.

To identify arterial blockages or vascular spasm within the skull, an intracranial scan may be performed, 93886 (transcranial Doppler study of the intracranial arteries; complete study). This study will be conducted to further discern where the blockage or spasm is located, he explains. The sonographer will place a narrow probe at several spots on the head behind the ear, for instance, or between the eye and nose. These areas act like windows and allow the ultrasonic waves to reach the arteries being examined.

As with the extracranial study (93880 or 93882), the bilateral study (93886) is conducted to discover a blockage or spasm during an initial complete evaluation, while the related limited code (93888, ... limited study) is most often used to evaluate postprocedure blood flow or the effect of various medical treatments for spasm.

How to Report Extra- and Intracranial Scans

Brebner notes that some radiology practices are being denied reimbursement when both an extracranial and intracranial study are performed on the same day. Some carriers may balk at paying for both scans, even though they are clearly necessary and use different imaging techniques to acquire the diagnostic information required, says Brebner.

To avoid denials, he recommends appending modifier -59 (distinct procedural service) and submitting documentation to indicate the clinical reasons for conducting both.

CPT includes one final code in the cerebrovascular arterial studies section 93875 (non-invasive physiologic studies of extracranial arteries, complete bilateral study [e.g., periorbital flow direction with arterial compression, ocular pneumoplethysmography, Doppler ultrasound spectral analysis]) that Brebner identifies as having limited applicability. It is seldom used any more. It describes a study using older technology, and the code may be deleted in the future.

Brebner also cautions radiologists against coding a complete study when only a limited one was performed. There are times when the ordering physician requests a complete study, but it is either not clinically indicated or technically possible. For instance, perhaps only a few of the vessels can be visualized. Many practices nonetheless code the complete study, but that is incorrect. If only a portion of the vessels was studied, then the practice must report only a limited scan, no matter what was originally ordered.