John McGahan, M.D.

John P. McGahan, M.D.



Radiology - Interventional Radiology

High Risk Obstetrical Imaging




  • Distinguished Professor of Radiology
  • Vice Chair of Academic Affairs, Department of Radiology
  • Director of Ultrasound, Department of Radiology


To see if John P. McGahan is accepting new patients, or for assistance finding a UC Davis doctor, please call 800-2-UCDAVIS (800-282-3284).

Lawrence J. Ellison Ambulatory Care Center

4860 Y St., Suite 3100
Sacramento, CA 95817
Driving Directions

Primary Phone:

Additional Phone Numbers

Physician Referrals: 800-4-UCDAVIS (800-482-3284)

Philosophy of Care

Dr. McGahan's philosophy is to consider the best treatment options for his patients to insure their best outcome for their disease or cancer.  He has developed and is an innovator in a variety of newer and less invasive precision therapies for focal cancer.

Clinical Interests

Dr. McGahan is a leading interventional and diagnostic radiologist. He has pioneered the use of several innovative techniques, including the use of radiofrequency ablation to treat primary and metastatic tumors (with results comparable to traditional surgery, but with fewer risks). He also has used ablation techniques in the treatment of primary and metastatic liver and renal tumors. He has treated benign and metastatic bone tumors as well. In addition, Dr. McGahan has investigated new techniques of tissue ablation for other organs, such as the prostate and breast. He has pioneered several other interventional techniques, including the development of percutaneous cholecystostomy as well as new techniques for endoluminal drainage of pelvic abscesses. He has recently studied the efficacy of abdominal ultrasound contrast in patients who have different diseases, including the use of ultrasound contrast in patients with hepatic or splenic injuries from blunt abdominal trauma.

Dr. McGahan was appointed as the chairperson by the American College of Radiology for its national Accreditation Program of Ultrasound Practices in the United States and Canada. He serves on the editorial board of several scientific journals and has edited six textbooks, including Diagnostic Ultrasound, A Logical Approach; Diagnostic Imaging of Fetal Anomalies; and most recently, an Atlas of Ultrasound Measurements.

Research/Academic Interests

Dr. McGahan's research is devoted to new minimally invasive methods of improving patient care.  Among his research has been the development of percutaneous techniques in minimal treatment of cancer using energies such as radiofrequency. 

He has also developed techniques for percutaneous insertion of catheters into the gallbladder for acute cholecystitis.  He has patented a device for ultrasound guidance of treatment of pelvic abscesses.


Abdominal Imaging
Body MRI
Radiofrequency Ablation

Center/Program Affiliation

UC Davis Comprehensive Cancer Center


M.D., Oregon Health & Science University School of Medicine, Portland OR 1974

B.S., Gonzaga University, Spokane WA 1970

Internship: UC Davis Medical Center, Sacramento CA 1974-1975


Orthopedic Surgery and Diagnostic Radiology, UC Davis Medical Center, Sacramento CA 1975-1979

Board Certifications

American Board of Radiology, 1979

American Board of Radiology, Vascular and Interventional Radiology, 1995

National Board of Medical Examiners, 1974

Professional Memberships

American College of Radiology, Fellow

American Institute of Ultrasound in Medicine, Fellow

American Roentgen Ray Society

Association of University Radiologists

International Hepato-Biliary Pancreatic Association

International Society of Biliary Radiology

Radiological Society of North America

Society of Biliary Radiology

Society of Radiologists in Ultrasound, Fellow

Honors and Awards

GI Lifetime Achievement Award at the SAR 2017 Annual Scientific Meeting and Educational Course in Hollywood, FL, 2017

Distinguished Professor � UC Davis Medical Center, 2013

US News & World Report � Top Physician USA, 2011

Select Recent Publications

Richards JR, McGahan JP. Focused Assessment with Sonography in Trauma (FAST) in 2017: What Radiologists Can Learn. Radiology. 2017 Apr;283(1):30-48.

Early HM, McGahan JP, Scoutt LM, Revzin M, Lamba R, Corwin M, Fananapazir G, Sekhon S. Pitfalls of Sonographic Imaging of Uterine Leiomyoma. Ultrasound Q. 2016 Jun;32(2):164-74.

Sidhar K, McGahan JP, Early HM, Corwin M, Fananapazir G, Gerscovich EO. Renal Cell Carcinomas:  Sonographic Appearance Depending on Size and Histologic Type. J Ultrasound Med. 2016 Feb;35(2):311-20.

McGahan JP. Challenges in abdominal/pelvic biopsy techniques. Abdom Imaging. 2013 Oct;38(5):1043-56.

McGahan JP, Bishop J, Webb J, Howell L, Torok N, Lamba R, Corwin MT. Role of FNA and Core Biopsy of Primary and Metastatic Liver Disease. Int J Hepatol. 2013;2013:174103.

McGahan JP, Wright L, Brock J. Occurrence and value of the color Doppler "line sign" after radiofrequency ablation of solid abdominal organs. J Ultrasound Med. 2011 Nov;30(11):1491-7.

McGahan JP, Loh S, Fitzgerald E, Koppie T, Evans CP, Dall'Era M, Li CS. Pretreatment imaging can be used to select imaging guidance, ultrasound alone versus CT plus ultrasound, for percutaneous renal radiofrequency ablation. AJR Am J Roentgenol. 2011 Nov;197(5):1244-50.

McGahan JP, Lamba R, Fisher J, Starshak P, Ramsamooj R, Fitzgerald E, Yen P. Is segmental enhancement inversion on enhanced biphasic MDCT a reliable sign for the noninvasive diagnosis of renal oncocytomas? AJR Am J Roentgenol. 2011 Oct;197(4):W674-9.

McGahan JP, Loh S, Boschini FJ, Paoli EE, Brock JM, Monsky WL, Li CS. Maximizing parameters for tissue ablation by using an internally cooled electrode. Radiology. 2010 Aug;256(2):397-405.

Stanhope KL, Schwarz JM, Keim NL, Griffen SC, Bremer AA, Graham JL, Hatcher B, Cox CL, Dyachenko A, Zhang W, McGahan JP, Seibert A, Krauss RM, Chiu S, Schaefer  EJ, Ai M, Otokozawa S, Nakajima K, Nakano T, Beysen C, Hellerstein MK, Berglund L, Havel PJ. Consuming fructose-sweetened, not glucose-sweetened, beverages increases visceral adiposity and lipids and decreases insulin sensitivity in overweight/obese humans. J Clin Invest. 2009 May;119(5):1322-34.