John McGahan, M.D.

John P. McGahan, M.D.



Radiology - Interventional Radiology

High Risk Obstetrical Imaging

Interventional Radiology





  • Distinguished Professor
  • Vice Chair of Academic Affairs
  • Director of Director of Abdominal Imaging Fellowship


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

My philosophy is to consider the best treatment options for  patients to insure the best outcome for their disease or cancer. I have developed and am an innovator in a variety of newer and less invasive precision execution of cancer therapies for various focal areas. These techniques include placement of percutaneous electrodes under image guidance to destroy tumors (cancer). This is done using minimally invasive techniques to insure minimal or no damage to surrounding tissue. These techniques allow patient recovery time to be less than traditional surgical techniques.

Clinical Interests

Dr. McGahan is a leading interventional and diagnostic radiologist. He has pioneered the use of several innovative techniques, including the use of radio-frequency 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. 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 seven textbooks, including Diagnostic Ultrasound, A Logical Approach; Diagnostic Imaging of Fetal Anomalies; and most recently, an Atlas of Ultrasound Measurements and Fundamentals of Emergency Ultrasound.

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 radio-frequency and microwave energy. For instance, he has recently published his results of treatment of renal cell carcinoma with an overall effective cure rate of 96% with minimal side effects. 

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

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,

American Board of Radiology, Vascular and Interventional Radiology,

National Board of Medical Examiners,

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

Castle Connolly - America's Top Doctors for Cancer, 2015, 2016, 2017, 2018, 2019

US News & World Report � Top Physician USA, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019

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

Select Recent Publications

Grewal A, Khera SS, McGahan JP, Wilson M, Loehfelm TW, Dall'Era MA, Evans CP. Utility of Intraprocedural Contrast-Enhanced CT in Ablation of Renal Masses. AJR Am J Roentgenol. 2020 Jan;214(1):122-128. doi:10.2214/AJR.19.21584. Epub 2019 Sep 18. PMID:31532258.

Kim NY, Lubner MG, Nystrom JT, Swietlik JF, Abel EJ, Havighurst TC, Silverman SG, McGahan JP, Pickhardt PJ. Utility of CT Texture Analysis in Differentiating Low-Attenuation Renal Cell Carcinoma From Cysts: A Bi-Institutional Retrospective Study. AJR Am J Roentgenol. 2019 Dec;213(6):1259-1266. doi:10.2214/AJR.19.21182. Epub 2019 Aug 6. PMID:31386573.

Kipper B, McGahan JP, Loehfelm TW, Fananapazir G. Is Ultrasound-Guided Core Biopsy as Safe as Fine-Needle Aspiration, and Does It Add Significantly to the Diagnosis of Suspected Peritoneal Malignancy? J Ultrasound Med. 2020 Feb;39(2):239-245. doi:10.1002/jum.15095. Epub 2019 Jul 22. PMID:31329309.

Elsayes KM, Kielar AZ, Elmohr MM, et al. White paper of the Society of Abdominal Radiology hepatocellular carcinoma diagnosis disease-focused panel on LI-RADS v2018 for CT and MRI. Abdom Radiol (NY). 2018 Oct;43(10):2625-2642. doi:10.1007/s00261-018-1744-4. PMID:30155697.

McGahan JP, Sidhar K, Fananapazir G, Early H, Corwin MT, Silverman SG, Seibert A. Renal cell carcinoma attenuation values on unenhanced CT: importance of multiple, small region-of-interest measurements. Abdom Radiol (NY). 2017 Sep;42(9):2325-2333. doi: 10.1007/s00261-017-1131-6. PMID:28389785.

Richards JR, McGahan JP. Focused Assessment with Sonography in Trauma (FAST) in 2017: What Radiologists Can Learn. Radiology. 2017 Apr;283(1):30-48. doi:10.1148/radiol.2017160107. PMID:28318439.

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. doi:10.1097/RUQ.0000000000000176. PMID:27233072.

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. doi:10.7863/ultra.15.03051. Epub 2016 Jan 6. PMID:26740493.

McGahan JP. Challenges in abdominal/pelvic biopsy techniques. Abdom Imaging. 2013 Oct;38(5):1043-56. doi:10.1007/s00261-013-0006-8. PMID:23748353.

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. doi:10.1155/2013/174103. Epub 2013 Nov 21. PMID:24369506.