Hiding in Plain Sight: Unexpected Findings on Chest X-Ray

Rich Gorilla CT.jpg

Notice anything unusual about this scan? In a study by Melissa Trafton Drew and Jeremy Wolfe, 83% of radiologists didn't notice the gorilla in the top right portion of this image when scrolling through five chest CT scans looking for lung nodules. (1) This is thought to be due to a phenomenon known as inattention blindness. When engaged in a demanding task, we may fail to perceive an unexpected stimulus that is in plain sight. If you don’t believe me, check this out:

The chest x-ray is one of the most commonly performed imaging tests. As emergency medicine physicians, we order chest x-rays to evaluate patients with a wide variety of complaints. Often times, it is our responsibility to interpret the x-ray and create a management plan before a radiologist has a chance to look at the image. This is true in community hospitals without radiologists available during night or weekend hours, in critically ill patients, or in trauma victims at large academic centers. Several studies have shown a discrepancy between the x-ray readings of emergency medicine physicians verses radiologists. (2,3,4,5) There is wide variability in the rate of misinterpretations reported, depending on the type of imaging, the experience level of the clinician, and the difficulty level of the chest x-ray findings, among other factors.

Chest x-ray interpretation is a vital skill as interpretation errors can have significant consequences.  False negatives may result in missing life-threatening conditions and worse patient outcomes. False positives may result in further testing, longer ED course and unnecessary interventions.  We are taught to be systematic in our approach to reading an image. However, it is not uncommon to zero in on the part of the chest x-ray we are interested in and unintentionally brush over the rest of the picture. This can lead to missed diagnoses and poorer patient outcomes.

With the importance of accurate chest x-ray interpretation skills in mind, let’s take a step back and review the basics:

The ABC's of Reading a Chest X-ray: 

First- check the patient information, the projection (AP or PA), the date it was taken. Review the aspects that affect the quality of the film.

  • Check the alignment (medial ends of clavicle equidistant from spinous process)
  • Check the inspiratory effort (10-11 posterior ribs in each lung field)
  • Exposure (is the image too bright or too dark? The vertebrae should be visible behind the heart)

Remember the pneumonic “RIPE” to evaluate the quality of an image - Rotation, Inspiration, Projection, Exposure. 



When ready to review the x-ray, consider the commonly used “A, B, C, D, E, F” system.

A - Airway- trachea, carina, right and left main bronchi

B - Bones and soft tissue- clavicles, ribs- posterior rand anterior, vertebral bodies, and sternum on lateral films. Look for any fractures, dislocations, or lytic lesions.

C - Cardiac- cardiac silhouette and mediastinum. The cardiac silhouette should be less than half of the thoracic cavity. AP films exaggerate heart size, so this rule does not apply. Assess the borders of the heart and the hilar structures

D - Diaphragm- right should be higher than left and you should see a gastric air bubble on the left. Is there any free air under the diaphragm? Evaluate the costophrenic angle and pleura (normally invisible due to thinness).

E - Everything else (lines and tubes, pacemakers, artificial valves)

F - Fields- FINALLY, evaluate the lung fields. Lungs are the area of greatest interest, so it is helpful to keep this at the end to prevent distraction. Divide each lung into three “zones” when reading a chest x-ray. These do not correlate with the lobes. Remember, there are 2 lobes on the left (upper and lower) and 3 on the right (upper, middle and lower). 



There are several things that do not fit perfectly into the A-E categories.

  • Apices
    • Look again at the lung above the clavicles
  • Retrocardiac space
    • Look for consolidation or a mass in this region
  • Below the diaphragm
    • Remember that the lungs extend below the diaphragm posteriorly. Look out for consolidation or lesions on the lateral film.
  • Soft-tissue abnormalities
    • Don’t forget to look for air, foreign bodies, and other soft tissue abnormalities.

Now that we have refreshed your memory, it’s time to practice! Imagine that you are in a small community setting, working the overnight shift. There are no radiologists available until the morning and it is up to you to read the chest x-ray.

Go through the examples below and see what findings you can pick up on these chest x-rays.

Case 1: Find the abnormality.

Case 1 answer: This patient has pneumomediastinum. Air appears as curvilinear lucencies outlining the mediastinum. Note the continuous diaphragm sign- the entire diaphragm is visualized as air in the mediastinum separates the heart and the superior surface of the diaphragm.

Case 2: Find the abnormality

Case 2 answer: This patient has a left shoulder dislocation. The humeral head is displaced from the glenoid of the scapula.

Case 3: Find the abnormality

Case 3 answer: This patient has a right middle lobe collapse. This is easier to visualize on the lateral view, where a triangular opacity overlying the cardiac silhouette can be seen. It can be difficult to see a middle lobe collapse on frontal projections. You may notice that the horizontal fissure is no longer visible or that there is blurring of the right heart border. (6)

For more information, check out https://radiopaedia.org/articles/right-middle-lobe-collapse

Case 4: Find the abnormality 

Case 4 answer: The central line placed in the right neck soft tissue crosses the midline. This line was placed in the carotid artery.


Case 5: Find the abnormality

Case 5 answer: Misplaced tooth. Notice the ovoid, radiopaque foreign body in the right mainstem bronchus.

Case 6: Find the abnormality

Case 6 answer: This patient has a left lower lobe pneumonia. There is a positive spine sign on the lateral projection. The spine normally becomes more radiolucent as you progress inferiorly given the increased amount of air containing lung overlying the spine as you travel downwards. Where there is fluid, a mass, or a consolidation in the lower lung fields, the vertebral bodies appear more radiodense.  

For more information, check out http://learningradiology.com/notes/chestnotes/spinesign.htm and https://radiopaedia.org/cases/left-lower-lobe-pneumonia-10

Case 7: Find the abnormality



Case 7 answer: This patient has Chilaiditi syndrome. In this syndrome, the colon is positioned between the liver and the diaphragm which can appear as free air under the diaphragm. Notice the rugal folds, this helps differentiate bowel containing gas from free air.

For more information, check out: https://radiopaedia.org/articles/chilaiditi-syndrome

Another example of Chilaiditi Syndrome:



Here is an example of actual pneumperitonium:



Case 8: Find the abnormality.


Case 8 answer: This patient has a left pneumothorax. This patient is supine at the time of this image (like many of our back-boarded and collared trauma patients). Notice the abnormally deep costophrenic angle on the left. This is known as the deep sulcus sign and is present because air collects in the non-dependent potions of the pleural space (anteriorly and basally when the patient is supine, apex when the patient is upright).

Case 9: Find the abnormality:


Case 9 Answer: This x-ray is NORMAL. It looks like this patient has a left pneumothorax on first glance, but the pleural line you think you see is actually a skin fold. (7) Notice that the pulmonary vessels extend to the outer edge of the lung fields.

For more information, check out: http://www.wikiradiography.net/page/Patterns+of+Misdiagnosis+in+Plain+Film+Radiography section 16 on artifacts.

Case 10: Find the Abnormality.

Case 10 Answer: The OGT is malpositioned and is entering the right mainstem bronchus and terminating in the right lung.

Case 11: Find the Abnormality.


Case 11 Answers: There is a comminuted fracture through the body of the right scapula. Fractures of the scapula usually occur in association with injuries to the ipsilateral lung, thoracic cage and shoulder girdle. Presence of a scapula fracture mandates further investigation for associated injuries. (8)

Case 12: Find the abnormality.

Case 12 Answer: This patient has extensive pneumomediastinum extending cranially into the neck. There is extensive soft tissue emphysema about the chest wall. This occurred after a coughing fit (believe it or not). No evidence of pneumonia or pneumothorax is seen, although it is difficult to visualize the lung fields with the overlying subcutaneous emphysema.


Chest x-ray interpretation is a vital skill as errors can lead to missed diagnoses and worse patient outcomes. Adopt a systemic approach to reading a chest x-ray and use it every single time. Use the ABCDEF pneumonic to guide your interpretation and to avoid overlooking an abnormality that are hiding in plain sight.

Faculty Reviewer: Robert Tubbs, MD


  1. Drew T, Vo ML, Wolfe JM. The invisible gorilla strikes again: sustained inattentional blindness in expert observers. Psychol Sci 2013;24:1848-53.
  2. Petinaux B, Bhat R, Boniface K, Aristizabal J. Accuracy of radiographic readings in the emergency department. Am J Emerg Med 2011;29:18-25.
  3. Safari S, Baratloo A, Negida AS, Sanei Taheri M, Hashemi B, Hosseini Selkisari S. Comparing the interpretation of traumatic chest x-ray by emergency medicine specialists and radiologists. Arch Trauma Res 2014;3:e22189.
  4. Soudack M, Raviv-Zilka L, Ben-Shlush A, Jacobson JM, Benacon M, Augarten A. Who should be reading chest radiographs in the pediatric emergency department? Pediatr Emerg Care 2012;28:1052-4.
  5. Nitowski LA, O'Connor RE, Reese CLt. The rate of clinically significant plain radiograph misinterpretation by faculty in an emergency medicine residency program. Acad Emerg Med 1996;3:782-9.
  6. Right Middle Lobe Collapse. at https://radiopaedia.org/articles/right-middle-lobe-collapse.)
  7. Patterns of Misdiagnosis in Plain Film Radiography. at http://www.wikiradiography.net/page/Patterns+of+Misdiagnosis+in+Plain+Film+Radiography.)
  8. Baldwin KD, Ohman-Strickland P, Mehta S, Hume E. Scapula fractures: a marker for concomitant injury? A retrospective review of data in the National Trauma Database. J Trauma 2008;65:430-5.

Money Minutes for Doctors #5 - Side Gigs for Physicians

Welcome to this month's edition of Money Minutes for Doctors. In this, our 5th episode, we take a glimpse at the topic of the side gig for those in the medical community. We have heard a lot about the "gig economy" in recent years. From Uber to Airbnb, side opportunities are defining ways to enhance one's income potential. It is no different for those of us in medicine and creative possibilities abound. Back again to help us navigate this emerging economical opportunity is Ms. Katherine Vessenes, JD, CFP®, RFC, Founder and President of MD Financial Advisors.


About Ms. Vessenes:

Ms. Vessenes works with over 300 physicians and dentists from Hawaii to Cape Cod. Her firm uses a team of experts to provide comprehensive financial planning to help doctors build their wealth and protect their wealth while reducing taxes now and in the future. Katherine is a longtime advocate for ethics in the financial services industry; and has written three books on the subject of investment strategies. She has received many honors and awards including: numerous tributes from Medical Economics as a top advisor for doctors, multiple 5-Star Advisor Awards, honored as a Top Woman in Finance, in addition to being selected to be on the CFP® Board of Ethics. Katherine can be reached at: Katherine@mdfinancialadvisors.com or 952-388-6317. Her website: www.mdfinancialadvisors.com.

Quick Summary:

A side “gig” can be a great way to earn extra money and have tax advantages. Figure out what you are “worth”, calculate your hourly rate so you can better budget. This can help you budget your money and time. Considering outsourcing household chores to maximize your time usage i.e. lawn care, grocery shopping, cleaning etc.  

Entering the side gig market options include:

-locums work/extra shifts
-writing medical texts
-medical apps for smart phone
-medical consulting
-forensic medicine
-education/teaching i.e. MCAT prep courses
-CME education materal
-medical directorships at Nursing homes or medical spas
-lecture circuit
-blogs (medical or otherwise ) can offer affiliate links that offer a finders fee
-disability or health insurance reviews
-urgent care shifts
-physician coaching


Acetaminophen: Where is it Found? And How to Handle Too Much of It!


A 14-year-old girl with a history of suicidal behavior presents to a pediatric emergency department with polysubstance ingestion.  Over the last two days she has ingested variable amounts of lorazepam, alcohol, and DayQuil™ (acetaminophen, dextromethorphan, and phenylephrine).  She drank an unknown quantity of DayQuil™ the day prior and admits to drinking an entire bottle on the day of presentation.  The patient denies any current symptoms.

Vital signs:  T 97.9 F, BP 133/83, HR 114, RR 20, SpO2 100%

On examination, she is in no acute distress.  Her neurologic examination is non-focal with a Glasgow Coma Scale of 15.  Her abdomen is benign.  She has linear scars to the left forearm from self-injurious behavior.  She is cooperative, nonchalant about her ingestion, describes her mood as “numb”, and has a flat affect. 

Her laboratory analyses reveal an acetaminophen level of 65 mcg/mL.  Liver function tests are unremarkable, INR is 1.0, and ethanol is zero.  All other diagnostics are unremarkable.  Treatment is initiated, and she is admitted to Pediatrics for acetaminophen overdose.  


Acetaminophen, commonly referred to internationally as paracetamol, is one of the most widely used analgesics and antipyretics.  It is a major component of many over-the-counter and prescription medications (Table 1).  Each year, approximately 30,000 patients are hospitalized in the United States for acetaminophen toxicity, with half of overdoses thought to be intentional. (1)  Intentional pediatric ingestions typically occur in adolescents while unintentional ingestions are more common among younger children. (2)  The therapeutic dose in children is 15 mg/kg  every four to six hours.  The minimum toxic dose for an acute ingestion is 150 mg/kg. (3,4)  In chronic overdose, the minimum toxic threshold is 150-175 mg/kg over two to four days. (3,5)  

Table 1: Common Medications Containing Acetaminophen
Alka-Seltzer Plus ® NORCO® Sudafed®
Dayquil® Nyquil® Theraflu®
Excedrin® Paracetamol Tylenol® Brand Products
Hydrocet® Percocet® Vicks®
Lortab® Robitussin® Vicodin®
Mucinex® Singlet®

The clinical manifestations of acute acetaminophen poisoning in children are nonspecific.  Initially, patients may be asymptomatic or have mild symptoms such as nausea and vomiting.  Liver injury can occur after approximately 24 hours and manifest as right upper quadrant pain or tenderness, vomiting, jaundice, and elevations in transaminases and prothrombin time.  At peak liver injury, patients can present with signs of fulminant liver failure such as hepatic encephalopathy, systemic inflammatory response system, hypotension, and death. (6)

All patients in whom acetaminophen toxicity is suspected should have a serum acetaminophen concentration drawn.  In patient with a single acute ingestion, the time of ingestion should be established, as a serum acetaminophen concentration at four hours post-ingestion will determine the need for antidotal therapy with N-acetylcysteine (NAC).  The four-hour concentration should be plotted against the treatment nomogram, and concentrations in the probable hepatic toxicity range should be treated with NAC. (4,6,7)

 Figure        SEQ Figure \* ARABIC     1      . Treatment Nomogram for Acetaminophen Toxicity, Reproduced from Rumack et. al 1975 (      ADDIN EN.CITE
app="EN" db-id="dvwe5dx0rvpz05e95vs5vspfvs5xsae0e5vp"
B. H.</author><author>Matthew, H.</author></authors></contributors><titles><title>Acetaminophen
poisoning and toxicity</title><secondary-title>Pediatrics</secondary-title></titles><periodical><full-title>Pediatrics</full-title></periodical><pages>871-6</pages><volume>55</volume><number>6</number><edition>1975/06/01</edition><keywords><keyword>Acetaminophen/adverse
induced</keyword><keyword>*Chemical and Drug Induced Liver
Injury/prevention &
control</keyword><keyword>Cysteamine/therapeutic use</keyword><keyword>Humans</keyword><keyword>Hypoglycemia/chemically
induced</keyword><keyword>Kidney Papillary Necrosis/chemically
induced</keyword><keyword>Poison Control
(Linking)</isbn><accession-num>1134886</accession-num><urls><related-urls><url>https://www.ncbi.nlm.nih.gov/pubmed/1134886</url></related-urls></urls></record></Cite></EndNote>     7)

Figure 1. Treatment Nomogram for Acetaminophen Toxicity, Reproduced from Rumack et. al 1975 (7)

In chronic ingestions, the treatment nomogram cannot be used.  Laboratory testing for serum acetaminophen concentration and liver function should be obtained for any at-risk patient.  Patients with evidence of liver injury (AST greater than two times normal or greater than 120 IUL or those with serum acetaminophen levels greater than 30 mcg/mL should have antidotal therapy initiated. (5,6)

Gastric decontamination with activated charcoal is recommended in all pediatric patients who present within four hours of acetaminophen ingestion.  Contraindications include gastrointestinal obstruction or any altered mental status in which airway protection is a concern.  Endotracheal intubation should not be performed solely for the purpose of giving activated charcoal.  Activated charcoal has not been shown to reduce acetaminophen absorption when given greater than four hours after ingestion and is not recommended in this time frame.  Activated charcoal is given as a single dose of 1 g/kg by mouth (maximum 50 g). (8,9) 

Once the need for N-acetylcysteine antidotal therapy is determined, it should be given as soon as possible.  When given within 8 hours of ingestion, the mortality rate approaches 0; however, NAC may be beneficial up to 24 hours after ingestion.  NAC should be given intravenously (IV) if available; however, providers should be aware that IV NAC can cause severe anaphylactoid reactions.  Preparations should be made for immediate interventions if anaphylaxis occurs, and patients should be monitored closely during the initial 30 minutes of the infusion. (6,10)  Providers should also be aware that prothrombin time and INR can be artificially elevated by NAC, which can obscure signs of worsening liver function. (11) 

A well-established protocol for IV NAC dosing involves a 21-hour administration procedure detailed below.  Repeat acetaminophen levels, liver function tests, and INR should be repeated 9 hours into the protocol. (12,13)

Loading dose of 150 mg/kg IV (maximum 15,000 mg) in 200 mL dextrose 5% in water (D5W) infused over 60 minutes

Followed by

First maintenance dose of 50 mg/kg IV (maximum 5,000 mg) in 500 ml D5W infused over 4 hours

Followed by

Second maintenance dose of 100 mg/kg IV (maximum 10,000 mg) in 1000 mL D5W infused over 16 hours

Poor prognostic indicators for liver function include the King’s College Criteria.  Patients with acidosis with pH < 7.3 or patients with the combination of prothrombin time > 100 seconds and creatinine > 3.3 mg/dL and hepatic encephalopathy grade III – IV (marked confusion or coma) are considered high risk for fulminant liver failure and should be transferred to a liver transplant center. (14)


Given that the patient had an elevated acetaminophen level greater than 30 mcg/mL with multiple ingestions over the last 48 hours, she was treated with N-acetylcysteine.   Labs were rechecked at 19 hours after initiation of NAC.  Liver function tests and INR were stable.  Repeat acetaminophen level was < 10 mcg/mL.  She was ultimately discharged after Psychiatric evaluation with a home safety plan and outpatient Psychiatry follow up.

Faculty Reviewer: Dr. Jane Preotle


1.         Blieden M, Paramore LC, Shah D, Ben-Joseph R. A perspective on the epidemiology of acetaminophen exposure and toxicity in the United States. Expert Rev Clin Pharmacol. 2014;7(3):341-348.

2.            Myers WC, Otto TA, Harris E, Diaco D, Moreno A. Acetaminophen overdose as a suicidal gesture: a survey of adolescents' knowledge of its potential for toxicity. J Am Acad Child Adolesc Psychiatry. 1992;31(4):686-690.

3.            Kanabar DJ. A clinical and safety review of paracetamol and ibuprofen in children. Inflammopharmacology. 2017;25(1):1-9.

4.            Lewis RK, Paloucek FP. Assessment and treatment of acetaminophen overdose. Clin Pharm. 1991;10(10):765-774.

5.            Sztajnkrycer MJ, Bond GR. Chronic acetaminophen overdosing in children: risk assessment and management. Curr Opin Pediatr. 2001;13(2):177-182.

6.            Walls RM, Hockberger RS, Gausche-Hill M. Rosen's emergency medicine : concepts and clinical practice. In: Ninth edition. ed. Philadelphia, PA: Elsevier,; 2018: https://login.revproxy.brown.edu/login?url=https://www.clinicalkey.com/dura/browse/bookChapter/3-s2.0-C20141019850 Full text available from ClinicalKey Flex.

7.            Rumack BH, Matthew H. Acetaminophen poisoning and toxicity. Pediatrics. 1975;55(6):871-876.

8.            Chiew AL, Gluud C, Brok J, Buckley NA. Interventions for paracetamol (acetaminophen) overdose. Cochrane Database Syst Rev. 2018;2:CD003328.

9.            Spiller HA, Krenzelok EP, Grande GA, Safir EF, Diamond JJ. A prospective evaluation of the effect of activated charcoal before oral N-acetylcysteine in acetaminophen overdose. Ann Emerg Med. 1994;23(3):519-523.

10.          Bateman DN, Dear JW, Thanacoody HK, et al. Reduction of adverse effects from intravenous acetylcysteine treatment for paracetamol poisoning: a randomised controlled trial. Lancet. 2014;383(9918):697-704.

11.          Pizon AF, Jang DH, Wang HE. The in vitro effect of N-acetylcysteine on prothrombin time in plasma samples from healthy subjects. Acad Emerg Med. 2011;18(4):351-354.

12.          Prescott LF, Park J, Ballantyne A, Adriaenssens P, Proudfoot AT. Treatment of paracetamol (acetaminophen) poisoning with N-acetylcysteine. Lancet. 1977;2(8035):432-434.

13.          Yarema MC, Johnson DW, Berlin RJ, et al. Comparison of the 20-hour intravenous and 72-hour oral acetylcysteine protocols for the treatment of acute acetaminophen poisoning. Ann Emerg Med. 2009;54(4):606-614.

14.          O'Grady JG, Alexander GJ, Hayllar KM, Williams R. Early indicators of prognosis in fulminant hepatic failure. Gastroenterology. 1989;97(2):439-445.