Musculoskeletal Magnetic Resonance Imaging Lab (Krug Lab)

My main research interest relates to the assessment (MRI) and treatment (MR guided FUS) of lower back pain as well as bone and bone marrow health, and osteoarthritis. In particular, we develop methods to assess spine health (such as spinal endplate, disc and marrow changes) as well as bone and marrow quality in the hip. We use advanced MRI techniques such as MR fat quantification imaging based on Dixon, ultra-short-echo time (UTE) and high-intensity focused ultra-sound (HIFU). We investigate the use of high intensity focused ultrasound to treat lower back pain. More recently, we have developed UTE methods to characterize the calcified (deep) layer of cartilage.


We will have 2 oral presentations (Krug et al.) this year at the ORS meeting in New Orleans and ISMRM in Paris about Lower Back Pain where we will present our findings regarding the roles of cartilage endplate, vertebral fat, and disc health in patients with lower back pain using Quantitative MRI.


Most Recent Publications (2017)

  1. R. Krug, L. Do, V. Rieke, M.W. Wilson, M. Saeed. Evaluation of MRI Protocols for the Assessment of Lumbar Facet Joints after MR-Guided Focused Ultrasound Treatment. Journal of Therapeutic Ultrasound 6;4:14. (2017). PMCID: PMC4822243.
  2. E. Ozhinsky, M. Han, M. Bucknor, R. Krug, V. Rieke. T2-Based Temperature Monitoring in Bone Marrow for MR-guided Focused Ultrasound. Journal of Therapeutic Ultrasound (2017 in press).
  3. M. Bucknor, E. Ozhinsky, R. Shah, R. Krug, V. Rieke. The Effect of Sonication Duration and Power on Ablation Depth during MR-Guided Focused Ultrasound of Bone. JMRI (2017 in press).
  4. D. Lansdown, S. Lee, C. Sam, R. Krug, B. Feeley, C.B. Ma. A Prospective, Quantitative Evaluation of Fatty Infiltration Before and After Rotator Cuff Repair. OJSM (2017 in press).
  5. D.C. Karampinos, S. Ruschke, M. Dieckmeyer, M. Diefenbach, D. Franz, A.S. Gersing, R. Krug, Th. Baum. Quantitative magnetic resonance imaging and spectroscopy of bone marrow. JMRI (2017 in press).
  6. B. Berg-Johansen, M. Han, A.J. Fields, E.C. Liebenberg, B.J. Lim, P.E.Z. Larson, C. Gunduz-Demir, G.J. Kazakia, R. Krug, J.C. Lotz. Cartilage Endplate Thickness Variation Measured by Ultrashort Echo-Time MRI is Associated with Adjacent Disc Degeneration. Spine (2017 in press).
  7. G.J. Kazakia, J. Carballido-Gamio, A. Lai, L. Nardo, L. Facchetti, C. Pasco, C.A. Zhang, M. Han, A. Hutton Parrott, P. Tien, R. Krug. Trabecular Bone Microstructure is Impaired in the Proximal Femur of HIV-Infected Men with Normal Bone Mineral Density. QUIMS (2017 in press).

Our research on Hip Osteoporosis was recently featured on the title page of the JMRI.

As a part of the Musculoskeletal and Quantitative Imaging Research Group (MQIR) at UCSF, the Krug Lab develops new MR-based imaging techniques:

  • To assess bone strength in the context of osteoporosis and other diseases.
  • To measure changes in temperature in cortical bone during HIFU ablation and investigate HIFU facet joint ablation to treat lower back pain.
  • To quantify bone marrow fat content in the presence of trabecular bone.
  • To quantify fatty infiltraton in the shoulder muscles to predict surgical outcome of rotator cuff tears.
  • To assess cartilage degeneration in the shoulder.
  • To assess the quality of tendons and ligaments before and after treatment.
  • To visualize the spinal endplates to investigate back pain.
  • To improve image MR quality in the presence of metal implants. 



Oral Presentation at the ORS 2018 in New Orleans:

Krug et al.: Associations between Disc Biochemical Composition and Vertebral Body Fat Fraction using Quantitative MRI. 




Research Highlights


Quantifying Temperature Changes in Bone 

We have recently published our research on temperature assessment of bone during heating. The goal of this research is to monitor temperature in bone in-vivo during high intensity focused ultrasound (HIFU) ablation.

High Resolution Assessment of Bone Marrow Fat Content

Our group has been pioneering the assessment of bone marrow fat content in the presence of trabecular bone with high spatial resolution. We have recently evaluated this technique in phantoms and compared in-vivo with MR spectroscopy:

Figure shows typical in-vivo examples of high-resolution MRI images along with corresponding MRI Fat Fraction maps. The top row shows images from a young, healthy female. Image a) depicts the trabecular structure and image b) the corresponding Fat Fraction map. The high-resolution image shows a dense trabecular structure. The darker, hematopoietic bone marrow is clearly depicted and can be quantified on the Fat Fraction map b). The bottom row shows images from a postmenopausal woman who sustained a low impact fracture. The high-resolution image c) shows dense bone but the Fat Fraction map d) also reveals overall high bone marrow fat content as compared to b) where large areas of hematopoietic bone marrow are present.

Assessment of Temperature in Bone using MRI

We have recently shown for the first time that temperature changes can be measured in bone during heating using T1-UTE based MR imaging. We have presented these results at ISTU 2014 and ISMRM 2014 in oral presentations.