Radiology Coding Alert

Rely on your comprehensive set of skills to work out this real-world scenario.

Exam: MRI Left foot

Indication: Left medial foot and ankle pain and swelling. Plantar metatarsal pain for 2 weeks. Patient does not report trauma.

Technique: Sagittal T1 and STIR, short axis PD and STIR, long axis PD FS imaging is performed through the left midfoot and forefoot without contrast.

Impression:

1. There is focal soft tissue edema and swelling along the plantar aspect of the second metatarsophalangeal joint. Findings are suggestive of a partial-thickness tear/sprain involving the medial aspect of the plantar plate of the second metatarsophalangeal joint. There is a small joint effusion with evidence of mild capsulitis.

2. There is diffuse marrow edema within the proximal phalanx of the second digit. Differential diagnosis includes bone contusion and/or stress-related edema. There is no definite fracture identified in this region. Infection seems less likely as an etiology for the marrow edema, recommend clinical correlation with any clinical signs of infection

"First, based on the exam title and lack of contrast documented within the technique, you can conclude that you will be applying CPT^® code 73718 (Magnetic resonance [eg, proton] imaging, lower extremity other than joint; without contrast material[s])," says Lindsay Della Vella, COC, medical coding auditor at Precision Healthcare Management in Media, Pennsylvania.

Your next step in the process of analyzing the dictation report is to examine both the indication and the impression.

Disclaimer: For the sake space restraints, make the assumption that the findings do not provide any relevant or important information not referenced in the impression. However, in a real-life coding scenario, you should make sure no important information from the findings has been left out (or contradicted) in the impression. This includes information as subtle as incorrectly citing the right foot instead of the left.

As you can see in the indication, you are dealing with a patient who has experienced a few weeks of pain and swelling without any known trauma. The indication of no known trauma may be important when comparing the indication to the diagnoses listed in the impression (see the shoulder diagnosis article from this issue).

Now, your next objective is to examine the impression and assign the correct diagnosis code(s) for this examination. Based on the impression, you should make a note of the following diagnoses:

• Edema/swelling, small joint effusion with evidence of mild capsulitis along the plantar aspect of the second metatarsophalangeal joint.
• Diffuse marrow edema within the proximal phalanx of the second digit.

As you can see, the impression documents much more than the diagnoses listed above. However, the only definitive diagnoses are those listed in the bullet points. "If a coder reports nondefinitive diagnoses, they are effectively telling the insurance carrier that the patient has a given injury or disease despite the exam note lacking any conclusive results," states Amanda Corney, MBA, medical billing operations manager for Medical Resources Management in Rochester, New York. "This can negatively impact the patient as the diagnosis enters their permanent medical record. It can also result in charges of fraud against the provider," Corney explains.

In this case, when the report states that the findings are "suggestive" of a specific diagnosis, you should not make the assumption that the diagnosis is definitive. The same goes for any elaboration on potential differential diagnoses. A differential diagnosis is simply the provider's speculation on diagnoses that cannot be confirmed by imaging.

Now that you've got a firm understanding as to which diagnoses should and should not be omitted from your list of diagnosis codes, you can begin to translate the diagnoses in bullet points to their respective codes.

Since each of these diagnoses are somewhat ambiguous in respect to the underlying diagnosis, the primary diagnosis can be left up to your discretion. However, some payers prefer that you apply the most specific codes first.

At first glance, capsulitis may be the most specific of the diagnoses listed above. Since you are out of luck when searching under Capsulitis (joint) in the ICD-10 index, you should follow the "see also Enthesopathy" instruction for the correct diagnosis code for capsulitis of the second metatarsophalangeal joint. Ultimately, this will lead you to apply code M77.9 (Enthesopathy, unspecified) for lack of a more specific option. As for the bone marrow and localized edema, you should include the same diagnosis of R60.0 (Localized edema). Since the provider documents the swelling as within the metatarsophalangeal joint, you will find that Swelling ⇒ joint in the ICD-10 index leads you to "see Effusion, joint." The final diagnosis of effusion of the metatarsophalangeal joint corresponds to code M25.475 (Effusion, left foot).

Based on degrees of specificity between diagnoses, you should apply the diagnoses in the following order: M25.475, R60.1, M77.9.