Today’s pearl is short and sweet. Here’s a breakdown of common radiologic studies performed in the emergency department along with their sensitivities and specificities according to the available literature. You may be surprised by some of the findings and lack of evidence for commonly obtained studies.

Study

Sensitivity/Specificity (%) Plain Film Sensitivity/Specificity (%) CT Sensitivity/Specificity (%) Ultrasound
Small Bowel Obstruction 79-83/67-83 96/100 (fine cuts) 83/100
Nephrolithiasis 63/69 96/100 54/71 (although no difference from CT for clinically relevant stones)
Pneumonia 43.5/93 Reference 94/96
Traumatic Pneumothorax 75.5/100 Reference 98.1/99.2
Cholelithiasis 15-20 (no specificity found) 79.1/100 98/98
Retropharyngeal Abscess in Children 80/100 (small study) 64-100/45-82 (varies by study) Seems high, although large studies have yet to be done.

Sources:

Suri S, Gupta S, Sudhakar PJ, Venkataramu NK, Sood B, Wig JD. Comparative evaluation of plain films, ultrasound and CT in the diagnosis of intestinal obstruction. Acta Radiol. 1999 Jul;40(4):422-8. PubMed PMID: 10394872.

Smith-Bindman R, Aubin C, Bailitz J, Bengiamin RN, Camargo CA Jr, Corbo J, Dean AJ, Goldstein RB, Griffey RT, Jay GD, Kang TL, Kriesel DR, Ma OJ, Mallin M, Manson W, Melnikow J, Miglioretti DL, Miller SK, Mills LD, Miner JR, Moghadassi M, Noble VE, Press GM, Stoller ML, Valencia VE, Wang J, Wang RC, Cummings SR. Ultrasonography versus computed tomography for suspected nephrolithiasis. N Engl J Med. 2014 Sep 18;371(12):1100-10. doi: 10.1056/NEJMoa1404446. PubMed PMID: 25229916.

Ranabir S, Baruah MP, Devi KR. Nephrolithiasis: Endocrine evaluation. Indian J Endocrinol Metab. 2012 Mar;16(2):228-35. doi: 10.4103/2230-8210.93740. PubMed PMID: 22470859; PubMed Central PMCID: PMC3313740.

Johnston R, Lin A, Du J, Mark S. Comparison of kidney-ureter-bladder abdominal radiography and computed tomography scout films for identifying renal calculi. BJU Int. 2009 Sep;104(5):670-3. doi: 10.1111/j.1464-410X.2009.08542.x. PubMed PMID: 19694714.

Sheafor DH, Hertzberg BS, Freed KS, Carroll BA, Keogan MT, Paulson EK, DeLong DM, Nelson RC. Nonenhanced helical CT and US in the emergency evaluation of patients with renal colic: prospective comparison. Radiology. 2000 Dec;217(3):792-7. PubMed PMID: 11110945.

Self WH, Courtney DM, McNaughton CD, Wunderink RG, Kline JA. High discordance of chest x-ray and computed tomography for detection of pulmonary opacities in ED patients: implications for diagnosing pneumonia. Am J Emerg Med. 2013 Feb;31(2):401-5. doi: 10.1016/j.ajem.2012.08.041. Epub 2012 Oct 18. PubMed PMID: 23083885; PubMed Central PMCID: PMC3556231.

Blaivas M, Lyon M, Duggal S. A prospective comparison of supine chest radiography and bedside ultrasound for the diagnosis of traumatic pneumothorax. Acad Emerg Med. 2005 Sep;12(9):844-9. PubMed PMID: 16141018.

Barakos JA, Ralls PW, Lapin SA, Johnson MB, Radin DR, Colletti PM, Boswell WD Jr, Halls JM. Cholelithiasis: evaluation with CT. Radiology. 1987 Feb;162(2):415-8. PubMed PMID: 3797654.

Pinto A, Reginelli A, Cagini L, Coppolino F, Stabile Ianora AA, Bracale R, Giganti M, Romano L. Accuracy of ultrasonography in the diagnosis of acute calculous cholecystitis: review of the literature. Crit Ultrasound J. 2013 Jul 15;5 Suppl 1:S11. doi: 10.1186/2036-7902-5-S1-S11. Epub 2013 Jul 15. PubMed PMID: 23902680; PubMed Central PMCID: PMC3711721.

Shea JA, Berlin JA, Escarce JJ, Clarke JR, Kinosian BP, Cabana MD, Tsai WW, Horangic N, Malet PF, Schwartz JS, et al.Revised estimates of diagnostic test sensitivity and specificity in suspected biliary tract disease. Arch Intern Med. 1994 Nov 28;154(22):2573-81. PubMed PMID: 7979854.

Boucher C, Dorion D, Fisch C. Retropharyngeal abscesses: a clinical and radiologic correlation. J Otolaryngol. 1999 Jun;28(3):134-7. Review. PubMed PMID: 10410343.

Glasier CM, Stark JE, Jacobs RF, Mancias P, Leithiser RE Jr, Seibert RW, Seibert JJ. CT and ultrasound imaging of retropharyngeal abscesses in children. AJNR Am J Neuroradiol. 1992 Jul-Aug;13(4):1191-5. PubMed PMID: 1636535.