An Assessment of Radio Frequency Induced Heating of a Vascular Stent during Magnetic Resonance Imaging of a Pig

Robert Nikolov ¹ , Michael Carl ² , Eric Chang ^1,3 , Christine Chung ^1,3 , Graeme Bydder ¹ , and Jiang Du ^1
1 Radiology, University of California, San Diego, San Diego, California, United States, ² GE Healthcare, Waukesha, Wisconsin, United States, ³ Radiology, VA San Diego Healthcare System, La Jolla, California, United States

In this study we demonstrate the use of a novel ultra short echo time (UTE) T ₁ sequence that combines a three-dimensional cones sequence preceded by a spin-lock preparation pulse for T ₁ contrast . T ₁ contrast is compared between this 3D sequence and a 2D radial sequence for: i) spherical CuSO4 phantom ii) ex-vivo meniscus sample and iii) in-vivo imaging of the human knee joint. Meniscus and tibial plateau values are reported as 18+/- 4ms and 36+/-3 ms respectively. The SNR efficiency and reduced eddy current artifacts afforded by the 3D cones sequence provides a robust sequence within a clinical relevant imaging time.

Kevin M Koch ¹ , Matthew F Koff ² , Parina Shah ² , and Hollis G Potter ^2,3
1 Biophysics and Radiology, Medical College of Wisconsin, Milwaukee, WI, United States, ² Radiology and Imaging, Hospital for Special Surgery, NYC, NY, United States, ³ Weill Cornell Medical College of Cornell University, NYC, NY, United States

Recent clinical patterns have shown an increasing trend of soft-tissue complications near total hip replacements, particularly those with metal on metal bearing surfaces. The presence of substantial metallic debris can highlight implant malfunction correlated to wear of the bearing surfaces. Metallic debris generates a resonance frequency shift that can be detected using MRI methods. Unfortunately, conventional image artifacts confound traditional methods for detailed frequency shift assessments near implants. Here, we demonstrate quantifiable image contrast highlighting cobalt-chromium particle deposits near metal implants using MAVRIC field maps and locally applied dipolar projection background field removal methods.

Jutta Ellermann ¹ , Abraham Padua ² , Edward Auerbach ¹ , and Dingxin Wang ^1,3
1 CMRR, Department of Radiology, University of Minnesota, Minneapolis, Minnesota, United States, ² Siemens Healthcare, Houston, Texas, United States, ³ Siemens Healthcare, Minneapolis, Minnesota, United States

The utility for multiband accelerated TSE imaging was tested for FAI (Femoroacetabular Impingement), a common clinical indication for hip studies in young active patients. Conventional MR is limited in the assessment of hip cartilage due to insufficient resolution. Cartilage damage occurs deep within the tissue as a debonding from the acetabulum, a pattern uniquely ill suited for diagnosis with standard imaging at 3mm slice thickness. The overall acquisition time for this modified multiband accelerated TSE imaging protocol can be reduced and supplemented with dedicated sequences with increased slice resolution for improved diagnostic accuracy of cartilage delamination, the hallmark of FAI.

Hongda Shao ¹ , Michael Carl ² , Eric Chang ¹ , Christine B Chung ¹ , Graeme M Bydder ¹ , and Jiang Du ^1
1 Radiology, University of California, San Diego, CA, United States, ² GE Healthcare, San Diego, CA, United States

Tendon is a highly ordered collagen-rich fibril tissue links muscle to bone. Multiple water components with distinct MR relaxation times exist in the tendon. In this study, we aimed to study the multiple water components in the Achilles tendon, and investigate its MTR as a function of MT pulse frequency offset in healthy volunteers and patients with tendon rupture using a clinical 3T scanner

Masami Yoneyama ¹ , Makoto Obara ¹ , Yuriko Ozawa ² , Hajime Tanji ³ , Masanobu Nakamura ¹ , Tomoyuki Okuaki ¹ , Takashi Tabuchi ² , Satoshi Tatsuno ² , Ryuji Sashi ² , and Marc Van Cauteren ^1
1 Philips Electronics Japan, Tokyo, Japan, ² Yaesu Clinic, Tokyo, Japan, ³ Imaging Center, Kita-Fukushima Medical Center, Fukushima, Japan

This study showed a new scheme for MR neurography of the wrist by using phase-cycled diffusion-sensitized driven equilibrium (pcDSDE) technique for achieving high-resolution MR neurography in the wrist. pcDSDE sequence clearly showed both anatomies and courses of median nerve, ulnar nerve and their branches. Furthermore, this sequence could offer gself-fusionh images simultaneously by using two types of reconstructed images (neurography images and anatomical images). DSDE sequence has great potential to stably depict peripheral nerves in the extremities.

Michael Dieckmeyer ¹ , Stefan Ruschke ¹ , Holger Eggers ² , Hendrik Kooijman ³ , Ernst J. Rummeny ¹ , Jan S. Bauer ⁴ , Thomas Baum ¹ , and Dimitrios C. Karampinos ^1
1 Diagnostic and Interventional Radiology, Technische Universitt Mnchen, Munich, Germany, ² Philips Research Laboratory, Hamburg, Germany, ³ Philips Healthcare, Hamburg, Germany, ⁴ Diagnostic and Interventional Neuroradiology, Technische Universitt Mnchen, Munich, Germany

The quantification of the apparent diffusion coefficient (ADC) of water in vertebral bone marrow has shown merit towards differentiating between benign and malignant vertebral compression fractures and towards indirectly investigating bone matrix changes in patients with osteoporosis. Vertebral bone marrow contains both water and fat components. Therefore, the extraction of water ADC can be biased by incomplete fat suppression of the secondary fat peaks close to the water peak, when using a spectrally selective fat suppression technique. The present work proposes a methodology to correct for the confounding effect of incomplete fat suppression in bone marrow water ADC quantification.

Anna M. WANG ^1,2 , Adrian Tsang ^1,2 , and Ed X. Wu ^1,2
1 Laboratory of Biomedical Imaging and Signal Processing, Hong Kong, Hong Kong, Hong Kong, ² Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong, Hong Kong, Hong Kong

This study compared the capability of diffusion weighted MRS (DW-MRS) and chemical exchange saturation transfer (CEST) methods in detecting and characterizing the ECM degradation during the early stage of IVDD in an ex vivo model. The apparent diffusion coefficient (ADC) of glycosaminoglycan (GAG) increased drastically immediately after papain injection, while the GAG concentration measured by both MRS and CEST method shared a similar but slow decreasing trend which happened later than the GAG ADC increase. The GAG ADC value, which is free from the influence of the GAG concentration, is an important potential marker for detecting the onset of the ECM degradation in IVDD.

Prachi Pandit ¹ , Martin Kretzschmar ¹ , Valentina Pedoia ¹ , William Dillon ¹ , and Sharmila Majumdar ^1
1 Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, United States

Regional variation of T1p and T2 values within the nucleus pulposa (NP) and annulus fibrosa (AF) of intervertebral discs (IVDs) has the potential of being a powerful biomarker for degenerative disc disease (DDD), much more so than just their mean values.

Osamu Togao ¹ , Akio Hiwatashi ¹ , Tatsuhiro Wada ² , Koji Yamashita ¹ , Kazufumi Kikuchi ¹ , Chiaki Tokunaga ² , Yuriko Suzuki ³ , Jochen Keupp ⁴ , and Hiroshi Honda ^1
1 Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan, ² Division of Radiology, Department of Medical Technology, Kyushu University Hospital, Fukuoka, Fukuoka, Japan, ³ Philips Electronics Japan, Tokyo, Japan, ⁴ Philips Research, Hamburg, Germany

Glycosaminoglycan CEST (gagCEST) imaging is an emerging molecular MR imaging technique to directly measure in-vivo GAG content in cartilaginous tissue. In this study, we demonstrated the utility of this method in assessments of lumbar intervertebral disc (IVD) degeneration by comparing with T1-rho, an established quantitative biomarker of IDD, and conventional morphological assessments. GagCEST correlated with T1-rho and Pfirrmann grades in lumbar IVD degeneration. GagCEST can provide a quantitative measure to assess degeneration of IVDs.

Volkan Emre Arpinar ¹ , Ali Ersoz ² , and L Tugan Muftuler ^1,3
1 Department of Neurosurgery, Medical College of Wisconsin, Milwaukee, Wisconsin, United States, ² Department of Boiphysics, Medical College of Wisconsin, Wisconsin, United States, ³ Center for Imaging Research, Medical College of Wisconsin, Wisconsin, United States

Nutrient transport to the discs through the endplate region was studied using Dynamic Contrast Enhanced MRI. Data were acquired from subjects with varying degrees of disc degeneration. Spatial maps of contrast enhancement were generated for each endplate and subchondral bone region in the lumbar area. A template for vertebral body disc surface interface was generated and enhancement maps were registered to this template for analysis across all subjects and all lumbar levels. Average enhancement maps were calculated for healthy, moderately degenerated and highly degenerated discs and the results revealed major pathologic changes in the endplate regions as the discs degenerate.