Pareidolia—Friend or Foe in the Echo Lab?

I began writing this month’s editorial during a trip out West to visit as many national and state parks as possible during a short period of time (Figure 1). With careful planning and willingness to go all-in, we covered nearly 2,000 miles through Nevada, Utah, Arizona, Colorado, and the Navajo Nation. In total, we visited and hiked in 6 national parks, 2 Navajo national parks, 7 national monuments, and 6 state parks (Table 1).

Figure 1.

The Editor-in-Chief hard at work in Bryce Canyon, Utah.

Table 1.

Destinations during 1-week Western USA adventure (road map available upon request)

National parks	Navajo Nation	State parks	Monuments
Black Canyon (Gunnison)		Coral Pink Sand Dunes	Hovenweep
Arches	Antelope Canyon	Anasazi	Grand Staircase Escalante
Canyonlands	Monument Valley	Dead Horse Point	Colorado National
Capital Reef	National monument	Goblin Valley	Canyon of Ancients
Bryce Canyon		Goosenecks	Bears Ears
Zion		Kodachrome Basin	Vermillion Cliffs

My joy in exploring (on foot, bike, or car) and discovering new places—each associated with new sensations—was in full swing and served as a reminder to me once again why I love echocardiography. If you think this association is too far-fetched, all will become clear as you continue reading.

Seeing ancient geography imprinted with dinosaur footprints forced me to become a detective at solving the mystery of their creation. Imagine what phenomenal set of circumstances it takes for a footprint to remain visible for us to look at 100 million years after it was first made. This fascination with deciphering and explaining what I was looking at rather than simply looking at it was another clear signal that my decision to focus my career on echocardiography was spot-on. In my opinion, echocardiographers are explorers and detectives of living beings. The sonographers are the guides that help us explore our surroundings. The guides know each valley and mountaintop, each cavity and valve, inside and out. They may select the fastest, or safest, or most beautiful route toward our destination. All sonographers will likely appreciate this comparison since they provide the same artistic efforts while guiding us through the heart.

There were many visitors from around the world at these iconic locations, and I believe they also have counterparts in the world of echo. Like the referring providers, it is the visitors who serve an important role as the individuals who keep the parks open and working efficiently. They are not experts like the explorer/detective physicians, and most certainly they are not like the sonographer guides, but without visitors, there would be no reason to have these protected and often sacred areas maintained. The referring providers are the ones who keep the echo lab operating in the most efficient manner. They let us know when discrepancies exist in our reports so we can make amendments; similarly, it is the visitor who lets the park ranger know about a hazard on a trail needing repair.

We would hike for miles while exploring the rim or the floor of a canyon. Sometimes there would be an overwhelming impression of nearly too much beauty. This would cause a brief sensation of fear that we might become blasé about the incredible but vast and recurring visual rewards. Around each corner or over each mountain top or hill crest, the views would change and offer additional eye-catching scenes of water flowing into waterfalls, rock caves, windows, and arches, with the occasional deer, Kaibab squirrel, or even a family of bighorn sheep including 5 babies. Learning echocardiography, you quickly realize that hidden just beneath the surface of the patient is a myriad of findings requiring you to move from acoustic window to acoustic window as you make your way along various anatomic sights. With time, you learn to recognize these views and appreciate both their beauty and their complexity.

On this trip, I was reminded that there is a major difference in the captured image with very slight changes in perspective and lighting. As all sonographers know, this is also true during echocardiography. Positioning a patient slightly more or less in the left lateral decubitus position will alter the window and may suddenly open up a new horizon with additional, relevant findings. Never before has echocardiography had such an opportunity to utilize the changes in lighting perspective to assist in visualizing anatomy than with photorealistic enhancements, which is similar to photographic variations determined by the sunrise or sunset perspective. Looking around in the massive canyons and mountains out West, it is important to include something for scale in your image. Having pictures without people is always special as it provides a sense of individuality and independence, but it may leave the person looking at the picture without an understanding of the actual immensity. Similarly, a very large left atrium next to a dilated cardiomyopathy may look normal despite having a left atrial volume index ≥ 60 mL/m².

Still pictures will eventually tell a story of where we were and what we saw, but a series of still images in isolation without accompanying depth and perspective will never fully capture the beauty of actually being there. Once again, the correlation to the interpretation of an echo image is similar. Whether it is an M-mode image or a conventional two-dimensional or volume-rendered three-dimensional cine, I am certain that we can all recall the many times that an expert peer provided additional clarity to our initial interpretation.

Death and Rescues in Zion National Park¹ is a popular book because each of us at one time or another has approached (or maybe exceeded) our own limits toward maximizing self-awareness. There are many risks to be taken in these environments, and we each have our chosen paths. Some will strive toward being conservative and remain behind the cliff rails, while others will be more aggressive and walk along the narrow cliff edge or atop a balancing rock spire. Those personalities drift into how we practice medicine.

Throughout every park I entered there were the actual paths and many other false paths that could be taken. Each path leads to both expected and unexpected findings. While scanning, there are also common paths that lead from parasternal long to short, and from apical 4 to 3, but on occasion, the guide may start with a subcostal. We explorers learn from the guides as they point out different items along the way. One path may quickly become a false path when we realize the structure measured was an embryologic remnant and not worthy of extra time or effort. These false trails notoriously result in us arriving at our final destination later than we anticipated, sometimes after more than 100 cine clips. At other times, the sonographer guide takes the physician explorer directly to their chosen destination by cutting across all geocardiographic obstacles and in doing so helps facilitate us more quickly solving the clinical puzzle with fewer images.

While in the Valley of the Goblins (Figure 2), I learned about pareidolia (meaning “the tendency to perceive a specific, often meaningful image in a random or ambiguous visual pattern”).² While those around me were seeing witches, gremlins, and other descriptive figures and faces in the hoodoos,³ I would frequently have to ask for visual clues in the shadows and geographic shapes. “Hey, over there I see a bear, wearing a skirt, holding a bunch of flowers while ice-skating…” I was simply not cut out for that! What was highlighted on the Bryce Canyon trail map as Queen Victoria⁴ was a beautifully shaped rock, but it was still a rock. As an echocardiographic explorer, I take pride in only seeing what is actually there. I avoid allowing my imagination to connect unconnected items as they can only keep me from my best detective work in solving what is contributing to this patient’s feeling of being ill (with the possible exception being 6:00 p.m. on Friday with more than 200 echo exams behind me that week).

Figure 2.

Giant “mushrooms” in Goblin Valley State Park, Utah.

On the final day of this weeklong adventure, we woke for an early Zion hike to the upper falls, then drove to Las Vegas for the long flight home, where upon waking the following morning, we were struck with an almost unreal sensation of remembering the previous 24 (or maybe 168) hours and what they entailed. Similarly, the patient with newly discovered left ventricular systolic dysfunction (among many other diagnoses) found on echo today may find themselves undergoing coronary angiography and bypass surgery a day later, wondering with a similar surreal sensation that it all happened exceedingly fast.

In this issue of CASE, the detective work from Lee et al., (a sticky situation) provides each of us with another striking potential cause for anechoic images after uneventful transesophageal echocardiography (TEE) placement. Reading this report forced me to ponder the poor-quality TEE images in my past that had been unexplained.

Ashraf et al., guide us through the serial evaluation of the oldest living patient with asymptomatic severe apical variant hypertrophic cardiomyopathy. Arguelles et al., remind us that sometimes not seeing something is as important as seeing it in a case of a congenitally absent left atrial appendage.

As our comfort grows with the ever-expanding indications for intracardiac devices, it requires echocardiographers to remain diligent in the exploration for potential complications. Dhaduk et al., provide an excellent demonstration of left atrial appendage occlusion device-associated thrombosis in 2 patients.

During TEE, the physician is both the explorer and the guide as they operate the probe and acquire the necessary images for arriving at a diagnostic destination. Kaletka et al., provide an excellent photographic journey during mitral valve repair of what a TEE explorer will see when the ligated appendage becomes inverted into the left atrium.

We have learned that transcatheter aortic valve implantation is frequently a rapid and safe procedure. We have also witnessed complications occasionally requiring an immediate valve-in-valve intervention. Ma et al., demonstrate that a transcatheter aortic valve implantation prosthesis positioned too far apically may interfere with the mitral valve apparatus, leading to devastating consequences.

Once again, CASE is complemented with a diverse set of important congenital heart disease reports. A 9-year-old with a surprising cause for a continuous murmur (Quien et al.), a 38-year-old with an untreated Gerbode defect who underwent coarctation stenting (Digrande et al.), and a 60-year-old with an incidental double-orifice mitral valve (Hardison et al). Each of these add to our understanding of the vast anatomic geography that our patients may be born with and that we must explore daily.

Indeed, some trips are short—without much excitement—and some trips are laborious and include many missteps and maybe even a fall (or 2) before you reach your final destination. We commonly had to recalibrate our position using GPS to gauge our location and compare notes with our guides to guarantee we were not too far offtrack. The best echo trips are similarly conducted with skillfully rehearsed collaboration between physician explorers and sonographer guides. There is an endless exhilaration at approaching your final destination and knowing with certainty that the diagnosis is within reach and very shortly a treatment plan will follow. But beware of pareidolia creeping in.

Remember, every echo you explore with your guide today has a teaching point, and every teaching point is a potential new CASE report!