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Karen Margaret Horton, M.D.

Karen Margaret Horton, M.D.

Headshot of Karen Margaret Horton
  • Director (Chair) of Radiology
  • Professor of Radiology and Radiological Science


Computed Tomography, Diagnostic Radiology, Virtual Colonoscopy more

Research Interests

CT Scan; CT Imaging; 3-D Computed Tomography

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Outside of Maryland & Washington D.C.

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The Johns Hopkins Hospital (Main Entrance)

Appointment Phone: 443-997-7237
1800 Orleans St.
Baltimore, MD 21287 map
Phone: 410-955-4100

Johns Hopkins Outpatient Center

Appointment Phone: 443-997-7237
601 N. Caroline St.
Baltimore, MD 21287 map
Phone: 410-955-4100

Johns Hopkins Bayview Medical Center

Appointment Phone: 443-997-7237
4940 Eastern Avenue
Baltimore, MD 21224 map
Phone: 443-997-1811

Johns Hopkins Medicine - White Marsh

Appointment Phone: 443-997-7237
4924 Campbell Boulevard
Suite 105
White Marsh, MD 21236 map
Phone: 443-442-2401 | Fax: 443-451-6986

Johns Hopkins Medical Imaging - Columbia

Appointment Phone: 443-997-7237
11055 Little Patuxent Parkway
Columbia Medical Center, Suite L9
Columbia, MD 21044 map
Phone: 443-574-5800 | Fax: 443-451-6986

Johns Hopkins Medicine - Green Spring Station

Appointment Phone: 443-997-7237
10803 Falls Road
Pavilion III, Suite 1100
Lutherville, MD 21093 map
Phone: 410-583-2700 | Fax: 443-451-6986

Johns Hopkins Medical Imaging - Bethesda

Appointment Phone: 443-997-7237
6420 Rockledge Drive
Suite 3100
Bethesda, MD 20817 map
Phone: 301-897-5656 | Fax: 443-451-6986


Karen M. Horton, M.D., is a Professor of Radiology and the Chair of the Russell H. Morgan Department of Radiology and Radiological Science. 

Dr. Horton’s clinical and research focus is on abdominal CT imaging, 3D imaging of the gastrointestinal tract and the mesenteric vessels, and virtual colonoscopy.  She has published over 170 scientific papers, numerous book chapters and was the Johns Hopkins principle investigator in the National CT Colonography Trial.

Dr. Horton graduated summa cum laude from the University of Notre Dame in 1988.  She attended the Johns Hopkins University School of Medicine, graduating in the top 10 percent of her class and was inducted into the AOA honor society.  After completing a radiology residency and a fellowship in cross-sectional imaging at Johns Hopkins, Dr. Horton joined the radiology faculty as an assistant professor in 1998.  

Dr. Horton was promoted to Associate Professor in 2002, and in 2008 became the 144th female to be promoted to Professor at Johns Hopkins.

In 2009, Dr. Horton assumed the role of Johns Hopkins Radiology Residency Program Director.  During her more than four years as program director, the residency program was ranked #1 by Aunt Minnie twice and #4 by Doximity.  During her tenure, in addition to making significant improvements to the residency curriculum, she increased diversity by recruiting more women and underrepresented minorities. 

From 2013 to 2014, Dr. Horton served as Acting Chair of the Department of Radiology at the Johns Hopkins Bayview Medical Center. Dr. Horton established subspecialty divisions and more fully integrated the Johns Hopkins Bayview Medical Center and The Johns Hopkins Hospital radiology divisions. She is a member of the Johns Hopkins Kimmel Cancer Center.

Dr. Horton has held numerous leadership positions within the Department of Radiology and Radiological Science, including Vice Chair of Operations in 2014, Executive Vice Chair in 2015, Interim Chair in 2016-2017. more


  • Director (Chair) of Radiology
  • Radiologist-in-Chief, The Johns Hopkins Hospital
  • Professor of Radiology and Radiological Science
  • Professor of Oncology

Departments / Divisions

Centers & Institutes



  • MD; Johns Hopkins University School of Medicine (1992)


  • Radiology; Johns Hopkins University School of Medicine (1997)


  • Radiology; Johns Hopkins University School of Medicine (1998)

Board Certifications

  • American Board of Radiology (Diagnostic Radiology) (1997)

Research & Publications

Research Summary

Dr. Horton's research focuses on the use of 3-D computed tomography (CT) imaging, particularly for imaging the pancreas and pancreatic tumors as well as Virtual Colonoscopy. She has co-authored numerous books and articles on the matter and remains an active participant in research studies related to CT imaging. More recently, Dr. Horton has become interested in Machine Learning and the potential role of artificial intelligence in radiology.

Clinical Trials

  • National CT Colonography Trial

  • National Lung Cancer Screening Trial

  • Screening for Early Pancreatic Neoplasia (CAPS III)

  • Mechanisms and Treatment of COPD Progression

Selected Publications

View all on PubMed

Tinari M, Fishman EK, Horton KM, Raman SP. The Ability to Multitask Effectively While Ensuring That All Customers Understand That They Are the Priority. J Am Coll Radiol. 2016 Oct;13(10):1279-1280.e1. doi: 10.1016/j.jacr.2016.07.007. No abstract available. PMID: 27712731

Kirwan WE, Fishman EK, Horton KM, Raman SP. An Eruption of Disruption: The Changing Landscape of Both Teaching and Learning. J Am Coll Radiol. 2016 Jul;13(7):868-870.e1. doi: 10.1016/j.jacr.2016.03.019. Epub 2016 May 13. No abstract available. PMID:27184915

Huang JH, Fishman EK, Horton KM, Raman SP. "From Gaming Machines to Thinking Machines . . . ". J Am Coll Radiol. 2016 Aug;13(8):1008-9. doi: 10.1016/j.jacr.2016.04.006. Epub 2016 May 28. No abstract available. PMID: 27245994

Brody WR, Fishman EK, Horton KM, Raman SP. Learning About Leadership by Making Mistakes.J Am Coll Radiol. 2016 Sep;13(9):1109-1110.e1. doi: 10.1016/j.jacr.2016.06.009. Epub 2016 Jul 27. No abstract available. PMID: 27474419

Johnson PT, Badger D, Horton KM, Fishman EK. Mitigating Misdiagnosis in Radiology: Educational CT CME Case Conference for Peer Review and Interpretative Improvement. J Am Coll Radiol. 2016 Jul 27. pii: S1546-1440(16)30361-1. doi: 10.1016/j.jacr.2016.05.015. [Epub ahead of print] No abstract available. PMID: 2747441

Academic Affiliations & Courses

Graduate Program Affiliation

Radiology Residency Program Director (2009 - 2014)
40 residents in program
Voted Best Radiology Residency by Aunt Minnie in 2012
Doximity Top Radiology Residency Program - #4 in 2014

Director, Cross-Sectional Imaging Fellowship (2000 - 2009)

Director, Virtual Colonoscopy Program (2005 - present)

3D Imaging Training Program
Started and maintain 3DCT education rotation for residents and fellows which includes instruction in 3D volume rendering, virtual colonoscopy and CT cardiac imaging.

Activities & Honors


  • Magna Cum Laude, RSNA Annual Meeting, 2002
  • Excellence in Design, RSNA Annual Meeting, 2008
  • Bronze Medal, ARRS Annual Meeting, 2000
  • Bronze Medal, ARRS Annual Meeting, 2001
  • Certificate of Merit, RSNA Annual Meeting 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2009
  • Exemplary Education Award, 2015


  • American Board of Radiology, 1997
  • American Association of Women Radiologists (AAWR)
  • Society of Computed Body Tomography and Magnetic Resonance Imaging

    Fellow Membership Committee

  • Society of Gastrointestinal Radiologists
  • Radiological Society of North America (RSNA), 1993

    Scientific Awards Committee 2003-2010 and Radiographics Selection Committee 2004-2010

  • American Roentgen Ray Society (ARRS), 1993

    SAM Committee 2005-2006 and CME Course Committee 2006 - 2009

  • American Roentgen Ray Society (ARRS), 2005 - 2006

    SAM Committee

Professional Activities

  • Editor, Critical Reviews in Computed Tomography, 2001 - 2005
  • Reviewer, American Journal of Roentgenology, 1999
  • Reviewer, Journal of Computer Assisted Tomography, 2001
  • Reviewer, RadioGraphics, 2001
  • Oral Boards Examiner, American Board of Radiology, 2005 - 2008

Videos & Media

Play Video:

Virtual Colonoscopy Q&A | Dr. Karen Horton

Lectures and Presentations

  • MDCT Evaluation after Pancreatic Surgery
    Lecture, 2012 RSNA Scientific Assembly and Annual Meeting
    Radiological Society of North America
  • Virtual Colonoscopy; MDCT of the Acute Abdomen, Small Bowel Neoplasms and Spleen
    Lecture, 2011
    Radiologic Society of South Africa
  • Virtual Colonoscopy; MDCT of Pancreatic Tumors
    Lecture, 2011
    University of Michigan School of Medicine
  • MDCT Imaging of the Pancreas, Stomach and PE; Virtual Colonoscopy
    Lecture, 2010
    Chinese Medical Society
  • MDCT of the Mesenteric Vessels
    Lecture, 2009 RSNA Scientific Assembly and Annual Meeting
    Radiological Society of North America
  • Virtual Colonoscopy Techniques and CTC Interpretation
    Course Director, 2008, ARRS Course on Virtual Colonoscopy
    American Academy of Physician Assistants
  • MDCT Staging of Gastric Malignancies
    Lecture, 2007
    European College of Radiology (ECR)
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