Patient with history of hypertension presents periumbilical abdominal pain radiating to the back. Minimal abdominal tenderness, no rebound or guarding, thoughÂ a pulsatile mass is felt.
The following ultrasound is obtained:
As the title suggests, the patient was diagnosed with an abdominal aortic aneurysm and vascular surgery was consulted.
We’re experimenting a bit with the GMEP.org system. It’s a great educational collaborative run by the folks who brought you Life in the Fast Lane. Worth checking out.
As you may know, we have a Vimeo channel with a growing video archive as well. Our goal is to make this site and its content as helpful and accessible a possible, so please let us know how we can improve!
With the proliferation of online educational modalities (blogs, educational websites, podcasts, twitter feeds) designed for rapid dissemination and translation of our basic Ultrasound knowledge to the bedsides around the globe, we must occasionally go back to the source – The Scientific Journal.
Listed below are several ultrasound-specific journals.
This patient presented with right upper quadrant abdominal pain. There was RUQ tenderness on exam, but no fever, rebound or Murphy sign. A point-of-care ultrasound was performed to assess for signs of cholecystitis and the following image was obtained. This prompted the operator to ask, “What the heck?”
What structures are visible here? How could you differentiate them? More after the break!
The Association of American Medical Colleges (AAMC) has written an article about ultrasound education at the medical school level. In the current edition of their widely distributed publication The Reporter, they describe programs at the University of South Carolina School of Medicine, University of California (Irvine) School of Medicine, and the Mount Sinai School of Medicine.
The article notes,
With rapid advancements in ultrasound technology, such scenarios as this are becoming more commonplace, as a handful of the nationâ€™s medical schools make ultrasound training a standard part of the curriculum. And there is a push to encourage more schools to use ultrasound.
To image something which moves, you must remain still. To image something which is still, you must move.
If you think on this long enough, the point is self-evident and requires no explanation. Or, just see some examples below.
We are pretty well adapted to seeing three dimensions at a time. Thus when imaging a moving structure like the heart, we hold the probe in a fixed position to obtain standard views. This allows us to focus on the movement, and cardiac presets optimize temporal resolution at the expense of spatial resolution. We are then seeing two spatial dimensions and one temporal dimension (heart moving in time).
It is very difficult to appreciate the anatomy and function of the heart, for example,Â when the probe is moving.
In contrast, imaging the right upper quadrant for fluid in Morison’s pouch requires a slow fan through the liver, diaphragm, and kidney. This allows us to appreciate the entire potential space where fluid can collect. Abdominal imaging is optimized for spatial resolution at the expense of temporal resolution, so be sure to move the probe slowly. Fanning through the entire structure of interest will often reveal pathology which was missed with a single-plane scan. Small gallstones, small amounts of peritoneal or pleural fluid, saccular aneurysms, and other maladies can fool a novice sonographer who isn’t thorough. In this case we are seeing three spatial dimensions.
Thoracic sonography is one of the most rapidly growing areas of emergency and critical care ultrasound. One very important emerging indication is to assess for lung consolidation. The characteristic appearance of consolidated lung is very sensitive and specific for pneumonia, but novices should heed some important pitfalls in making the diagnosis.
Special thanks to Jim Tsung, MD, MPH and Brittany Jones, MD for their tips, videos, and ongoing research in this important field! For further reading on this topic, please see this article.
Pitfall #1 – confusing thymus for a consolidation
Normal thymus in sagittal view:
Thymus (top half of screen) and heart (bottom right). Don’t confuse thymus for lung consolidation. Note there are no air bronchograms, but thymus has a faint speckled appearance.
Normal thymus in transverse view:
Thymus (top half of screen) and heart (bottom right). Don’t confuse thymus for lung consolidation. Note there are no air bronchograms, but thymus has a faint speckled appearance
Pneumonia adjacent to Thymus in transverse view:
Lung consolidation with air bronchograms (top left) adjacent to normal thymus (speckled appearance on top right) with heart (bottom right)
Pitfall #2 – mistaking spleen for consolidation.
This is an important pitfall for everyone to know about. The same issue applies to the liver & stomach. The sensitivity of lung US for pneumonia rises >90% if this mistake is avoided.
Left lower chest- sagittal view:
Be careful scanning the left lower chest (left anterior and left axillary line) – air in stomach and spleen may look like pneumonia if you don’t realize that you have scanned inferior to the diaphragm and past the end of the pleural line. Most common error by novices.
Left lower chest- transverse view:
Be careful scanning the left lower chest (left anterior and left axillary line) – air in stomach and spleen may look like pneumonia if you don’t realize that you have scanned inferior to the diaphragm and past the end of the pleural line.
Pitfall #3- missing pleural effusion
Here are a few examples to refresh your memory.
Left pleural effusion:
Pleural effusion (anechoic wedge just beneath ribs and pleura)
Air in stomach
Do not confuse spleen and air in stomach for pneumonia.
When evaluating for possible elevation in intracranial pressure, it has been shown that optic nerve sheath diameter (ONSD)Â measurements correlate with elevated intracranial pressures.(1,2) Â The optic nerve attaches to the globe posteriorly and is wrapped in a sheath that contains cerebral spinal fluid.Â The optic nerve sheath is contiguous with the dura mater and has a trabeculated arachnoid space through which cerebrospinal fluid slowly percolates.
ONSD Normal Ranges
< 5 mm
Children >1 yr
< 4.5 mm
Infants < 1 yr
The ONSD is measured 3 mm posterior to the globe for both eyes.Â A position of 3 mm behind the globe is recommended because the ultrasound contrast is greatest. Â It is best to average two measurements of each eye.Â An average ONSD greater than 5 mm is considered abnormal and elevated intracranial pressure should be suspected.
In severe cases of elevated ICP, one can see anÂ echolucentÂ circle within the optic nerve sheath separating the sheath from the nerve due to increased subarachnoid fluid surrounding the optic nerve. Â Ophthalmologists refer to this as theÂ crescent sign.
Â The Case
40 yo female patient presents with several months of frontal headache associated with photophobia and blurry vision. Â Symptoms have gotten much worse over the last few days and she has had difficulty reading and watching TV because of her visual symptoms. Â She denies fevers, chills, nausea, vomiting, or focal weakness. Â Pt is hypertensive 170/100. Â Her vital signs are otherwise normal.
This patient had enlarged ONSD (measurements were 6 mm bilaterally) as well as papilledema(arrow).
Lumbar puncture was performed. Â Opening pressure was 44. Â 30 cc’s of CSF was drained and the closing pressure was 11. Â The patient’s headache and visual symptoms improved . Â She was started on acetazolamide and admitted to the neurology service. Â MRI brain prior to lumbar puncture showed posterior scleral flattening bilaterally with protrusion of the optic nerve in the the globes bilaterally consistent with increased ICP.
This patient’s papilledema and increased ONSD correlated with a markedly increased opening pressure during lumbar puncture and suggests that ocular ultrasound may play a role in the ED management of patients with suspected pseudotumor cerebri.
Elevated intracranial pressure in the abscence of intracranial mass lesion.Â Most common in young, over weight women. If the diagnosis is missed, persistently elevated intracranial pressure can lead to optic atrophy and blindness.
Lumbar puncture to drain CSF to a normal opening pressure.
Medical:Â Diomox (acetazolamide), high dose steroids
The ability to diagnose papilledema using bedside sonography is useful to emergency physicians, as manyÂ non-ophthalmologistÂ clinicians do not feel confident in their ability to perform an accurate nondilated fundoscopic examination. (3) Â Ultrasound provides a useful alternative means of determining the presence or absence of papilledema in a patient in whom fundoscopy cannot be adequately performed.
 Geeraerts T, Launey Y, Martin L, et al. Ultrasonography of the optic nerve sheath may be useful for detecting raised intracranial pressure after severe brain injury. Intensive Care Med 2007;33(10):1704-11 [electronic publication 2007 Aug 1].Â PMID:Â 17668184
 Kimberly HH, Shah S, Marill K, Noble V. Correlation of optic nerve sheath diameter with direct measurement of intracranial pressure. Acad Emerg Med 2008;15(2):201-4.Â PMID:Â 18275454
 Wu EH, Fagan MJ, Reinert SE, Diaz JA. Self-confidence in and perceived utility of the physical examination: a comparison of medical students, residents, and faculty internists. J Gen Intern Med 2007;22 (12):1725-30 [electronic publication 2007 Oct 6]. Â PMID:Â 17922165