How Do We Explain ‘Incidental’ MRI Findings To Patients?

Doug Richie Jr. DPM FACFAS

When I first entered clinical practice over 30 years ago, diagnostic imaging studies were limited to plain radiographs, arthrography and nuclear medicine bone scans.

With the emergence and improvement of magnetic resonance imaging (MRI), we have better ability and accuracy to investigate and confirm the presence of pathologies in the foot and ankle. Unfortunately, this often opens up a can of worms as almost every MRI study reveals the presence of findings that are not related to the symptoms of the patient, i.e. so-called “incidental” findings.

How often do you order a MRI for an active athlete to investigate the integrity of the Achilles tendon and the study reveals a “sprain” of the anterior talofibular ligament? How often does the radiology report describe tendinosis and intrasubstance tearing of the peroneus brevis tendon? How do you explain these findings to an active patient who has no pain in the peroneal tendons and no recollection of spraining the ankle?

A new study published this month in the Journal of Foot and Ankle Surgery provided interesting verification of the prevalence of pathologies detected by MRI studies of patients with asymptomatic ankles.1 Galli and coworkers retrospectively studied MRI findings in 104 patients with asymptomatic ankles who had this exam for evaluation of pain or symptoms elsewhere in the foot. Fourteen percent of these patients demonstrated osteochondral lesions of the talus while one-third of these same patients demonstrated peroneal tendon pathology (31.48 percent in the peroneus brevis and 37.96 percent in the peroneus longus). More importantly, this same study showed that 62 percent of asymptomatic patients showed evidence of a torn anterior talofibular ligament while 38 percent showed a tear of the calcaneofibular ligament.

Three years ago, a study by Saxena and coworkers showed almost identical findings to the Galli study.2 The authors prospectively reviewed 102 MRI studies of asymptomatic ankles and found a 15 percent prevalence of osteochondral lesions of the talus and a 34 percent incidence of peroneal tendon pathology. Saxena and colleagues found a lower incidence of anterior talofibular ligament and calcaneofibular ligament pathology (29 percent and 11 percent respectively).

What do you tell your patients about these incidental findings? How do you explain a rupture of an ankle ligament that apparently has caused no disability to the patient? Should you treat or monitor an asymptomatic osteochondral lesion?

It is interesting to note the conclusions of the authors of these two studies, which had almost identical findings. Saxena and colleagues recommend that MRI not be the sole criteria for choosing surgical treatment of lateral ankle pathologies and they appropriately cited many studies showing the high success rate of functional rehabilitation of lateral ankle injuries.2 Galli and colleagues conclude that “subclinical pathologic features have the potential to progress and, therefore, should be monitored closely and treated if any symptoms develop.”1 They further state that “noting the OLT size and discussing lifestyle modifications could prevent additional degradation of native anatomic structures, and prevent additional degradation of native anatomic structures and, consequently, prevent subchondral collapse.”

I would question whether there is any evidence that lifestyle modification will prevent the progression of a small, asymptomatic osteochondral lesion of the talus. The etiology of these lesions is still a subject of debate and the role of lifestyle does not have a clear correlation to the lesion other than the small correlation with a history of ankle sprain. I would agree that one should share the findings with the patient but I would be cautious about recommending any lifestyle change in the absence of symptoms.

The bigger problem is the high prevalence of peroneal tendon pathology on almost all MRI studies taken of patients with and without symptomatology. What do we tell our patients who have no symptoms but significant MRI findings documenting poor health of their peroneal tendons? How many of these patients functioned beautifully with an active lifestyle long before MR imaging became popular?

What we need is a prospective study of these asymptomatic patients who have MRI-documented pathology of certain ankle structures. Over a period of five to 10 years, it would be interesting to see how many of them progressed in severity of the pathology or how many ultimately became symptomatic. My guess, based upon following many of these same types of patients in private practice, is that most patients remain asymptomatic and the MRI findings do not change.

My recommendation is to discuss all parts of the MRI study with the patient, including incidental findings. Certainly, it is prudent to make the patient aware that re-evaluation is necessary if any symptoms begin at the site of the incidental pathology. At the same time, most of these patients will do very well if they continue to carry out their current lifestyle and not worry about MRI findings that will probably never require treatment.

References
1. Galli MM, Protzman NM, Mandelker EM, Malhotra AD, et al. Examining the relation of osteochondral lesions of the talus to ligamentous and lateral ankle tendinous pathologic features: A comprehensive MRI review in an asymptomatic lateral ankle population. J Foot Ankle Surg. 2014; 53(4):429-433.
2. Saxena A, Luhadiya A, Ewen B, Goumas C. Magnetic resonance imaging and incidental findings of lateral ankle pathologic features with asymptomatic ankles. J Foot Ankle Surg. 2011; 50(4):413-415.

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