TRADITIONAL POSTER - ismrm

Poster Sessions
2407. Differential Neurochemical Responses in the Rat Striatum with Isoflurane or Ketamine/xylazine
Anesthesia: In Vivo Proton MRS Study at 16.4 T
Chi-Bong Choi 1 , Sung-Tak Hong 2 , Sang-Young Kim 3 , Dong-Cheol Woo 3 , Bo-Young Choe 3 , Kyung-Nam
Ryu 1 , Eun-Hee Kang 1 , Sung-Vin Yim 1 , Do-Wan Lee 3 , Rolf Pohmann 2
1 Kyung Hee University of Korea, Seoul, Korea, Republic of; 2 Max Planck Institue for Biological Cybernetics; 3 The Catholic
University of Korea
This study was to evaluate alterations in striatum metabolites of rats between anesthetized with isoflurane and ketamine/xylazine in vivo 1H-MRS at 16.4T,
and to investigate the appropriateness of anesthetic agents. The concentrations of Ala, Asc, Asp, GABA, Gly and PCr were significantly different between
isoflurane and ketamine/xylazine induced groups at the striatum. We demonstrated that metabolites in specific brain region can be differentially influenced
according to anesthetic agents. This study showed that the choice of anesthetic is significant in the setting of 1H-MRS. Appropriate anesthetic choice should
be pursued to exclude the effect of anesthetic agents on the target area.
Head & Neck Imaging: Normal to Cancer
Hall B Wednesday 13:30-15:30
2408. Movement-Artefact-Free Measurement of T 1 in the Human Eye to Determine Oxygenation of the
Vitreous Humour
Nicholas G. Dowell 1 , Edward H. Hughes 2 , Paul S. Tofts 1
1 Brighton and Sussex Medical School, Brighton, United Kingdom; 2 Sussex Eye Hospital, Brighton, United Kingdom
Accurate and precise T 1 mapping of the eyeball is difficult due to eye movement and image distortions. An accurate measure of T 1 could provide a noninvasive
determination of eye oxygenation since T 1 times are subtly increased by reduced partial pressure of oxygen (pO 2 ) of the vitreous humour in the eye.
Poor oxygenation leads to retinopathy and, in patients with low pO 2 at the retina, a vitrectomy may be performed, where the vitreous humour is extracted and
replaced by saline. However, there is no clear evidence that an increase in pO 2 is actually achieved by this procedure and MRI would provide an important
validation for ophthalmologists. We have developed a technique, using a TrueFISP acquisition sequence, which provides eye images with no movement
artefacts, no image distortion and good SNR. This permits the measurement of T 1 (and hence pO 2 ) from the vitreous humour of the human eye. Furthermore,
we show that asking a subject to fixate on a single point can control eye movement but the need to blink limits fixation to < 5 s. Consequently, we will
provide an audio/visual cue that warns the subject when they must fixate. This approach to eye imaging could dramatically improve imaging of the eye and
retina.
2409. Ultrashort Echo Time Imaging of the Middle Ear Ossicle: A Pilot Study
Koji Yamashita 1 , Takashi Yoshiura 1 , Akio Hiwatashi 1 , Hironori Kamano 1 , Yukihisa Takayama 1 , Eiki
Nagao 1 , Hiroshi Honda 1
1 Radiology, Kyushu university, Fukuoka, Japan
Our purpose was to assess the feasibility of ultrashort echo-time (uTE) imaging for visualization of middle ear ossicles in normal subjects. Twelve
volunteers with normal hearing levels were scanned at a 3.0T clinical unit using a dual-echo uTE sequence at TE1/TE2 = 0.14 ms/1.8 ms. In all subjects, the
middle ear ossicles were clearly visualized as a high signal intensity spot on short TE images bilaterally, while they were not visible in long TE images in
any of the subjects. To our knowledge, this is the first report of MR visualization of middle ear ossicles.
2410. Automatic Segmentation of Laryngeal Cartilages Using Support Vector Machines
R. Reeve Ingle 1 , Berhane H. Azage 1 , Joëlle K. Barral 1 , Kie Tae Kwon 1 , Edward G. Damrose 2 , Nancy J.
Fischbein, 2,3 , Dwight G. Nishimura 1
1 Electrical Engineering, Stanford University, Stanford, CA, United States; 2 Otolaryngology, Stanford University, Stanford, CA,
United States; 3 Radiology, Stanford University, Stanford, CA, United States
MR is critical in the staging of laryngeal cancer. However, the presence and extent of cartilage invasion is difficult to assess. In this work, automatic
intensity correction is integrated in a support vector machine algorithm, which is used to segment the cartilages from high-resolution MR images of the
larynx.
2411. Dynamic MRI of the Temporomandibular Joint at 3 Tesla Using a Gradient Echo Sequence
Yoon-Chul Kim 1 , John L. Go 2 , Sara Banerjee 2 , Meng Law 2 , Houchun Harry Hu 1 , Krishna S. Nayak 1,2
1 Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, United States; 2 Keck School
of Medicine, University of Southern California, Los Angeles, CA, United States
Dynamic MRI may be useful for assessing temporomandibular joint (TMJ) dysfunction. This application requires sub-millimeter resolution and adequate
contrast between the articular disc and surrounding tissue. A gradient echo sequence was optimized by first measuring the T 2 * values and then calculating
the parameters of flip angle, TE, and TR that maximize the CNR efficiency. The dynamics of the TMJ disc was visualized with a 3.2 second temporal
resolution, 0.5 × 0.5 mm 2 in-plane spatial resolution using a 6-channel Carotid coil at 3 Tesla.
2412. Chemical Shift Imaging in the Head and Neck at 3T: Initial Results
David K W Yeung 1 , Devin K. Fong 1 , Queenie Chan 2 , Ann D. King 1
1 Diagnostic Radiology and Organ Imaging, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong; 2 MR, Philips
Healthcare, Wanchai, Hong Kong
Proton MRS is useful to probe tissue metabolism in vivo and its application yields considerable information about tissue biochemistry. In the head and neck,
the detection of choline peak using single voxel spectroscopy has been found useful in confirming malignancy and treatment response. CSI is desirable for