Resources
LABORATORY: Center for Translational-CTI-
Director Andrew C. Larson, Ph.D.:
The Center for Translational Imaging (CTI) is situated on the Chicago campus of Northwestern University’s Feinberg School of Medicine. The facility is 4,500 square feet and is located in Olson Pavilion, which is adjacent to NorthwesternMemorialHospital. The facility is fully staffed with a full-time research nurse, 3 MRI technologists, and an administrative assistant. The MR technicians have more than 15 years experience and assist investigators with studies and add their imaging expertise to projects. They provide coverage from 7AM until 8PM 5 days a week and 9AM-5PM on Saturday and Sunday. The staff nurses provide support for studies that require monitoring or contrast agent administration. In addition we offer Basic Life Support training to make sure that the facility has the highest level of safety possible.
The laboratory contains 2 MRI scanners, animal holding and preparation rooms, and an Interventional Radiology Research Laboratory. The MRI scanners at the facility are used solely for research purposes. CTI maintains 2 state-of-the-art whole-body MRI scanners, a Siemens 1.5 T Espree and a Siemens 3.0 T Trio. Both MRI scanners are equipped with a high-performance gradient system, which have a maximum strength of 40mT/m; slew rate 200 mT/m/ms. The facility is also equipped with a Siemens C-ARM angiographic system and an MR simulator system that can be used to acclimate subjects to the magnet environment. The facility is equipped with an Abbott Point of Care blood analyzer (i-STAT 300, Abbott Labs). The analyzer is used for point of care renal function testing, which is performed prior to contrast administration. A Life Pak-20 defibrillator/monitor (Medtronic Emergency Response Systems, Inc., Redmond, Washington) and emergency medication cart are available for emergency situations. Many different coils are available to enhance imaging studies by providing signal reception and parallel imaging reconstruction.
Support equipment includes full physiologic monitoring equipment (BP, HR, SAO2, ETCO2), 2 different power injectors, in-room gas (O2, suction, and anesthesia gas evacuation), an animal anesthesia machine, and a full array of cushions and pads for positioning. The facility is equipped with an Abbott Point of Care blood analyzer (i-STAT 300, Abbott Labs). Positioning calipers are used to comfortably fix the head and reduce patient motion during the study. In addition, a vacuum fixation pillow is used to reduce subject motion and provide comfortable support to allow extended studies.
Functional imaging tools have been developed to make the setup for an experiment easy and reproducible. A high quality full frequency range auditory amplifier (Avotec) is used to deliver auditory stimuli via plastic tubing from the foot of the bed. The auditory system provides 2-way communication making it easier to explain the task to the subject. A slim line headphone set is used for maximum patient comfort while providing 30 dB of external sound attenuation. We have also implemented a noise cancellation method that allows users to record subject’s overt speech without the scanner noise. The noise suppression method creates a template of the noise form the scanner during the dummy period. The template is subtracted from the output of the microphone located in the bore of the magnet near the subject’s mouth. The algorithm reduces the scanner noise by 20 dB, allowing the user to clearly hear the subject’s response. The algorithm automatically detects the onset of the response for use in the analysis.
Visual stimuli are delivered to a custom rear projection screen placed inside the bore of the magnet approximately 24” from the subject. The subject views the stimuli via a mirror attached to the head coil that can be adjusted easily. Subject’s with poor vision can be corrected using our plastic optical lens kit and a plastic sports goggle. The images are projected onto the screen through a special waveguide in the back of the room. This eliminates any RF noise created by the projector. A custom lens is used to optimize the image on the rear projection screen creating a crisp, bright image that fills the subject’s field of view. Fiber optic buttons (4 of them) can be used to record the subject’s response to the stimuli. The buttons connect to the Cedrus RB610 response box. The subject’s response data are interfaced to the stimulation presentation software via a serial cable connection. With the additional filtered connectors on our patch panel, it is possible to interface any stimulus device (devices successfully implemented include: a hot/cold thermal stimulator, an IR eye tracker, a skin conductance device, and a 6 degree of freedom load cell) into the magnet room. A dedicated stimulus computer is located next to the main imaging console. A number of stimulus presentation programs are resident on this computer including Superlab, Cogent, E-Prime, and Presentation. There are interface cables that allow investigators to easily connect their own laptopsto the MR system and stimulation delivery equipment. The scanner’s trigger pulse is provided in TTL form as well as a pulse number delivered via a serial connection. The trigger can indicate the start of the volume or the initiation of each slice.
A recent addition to the functional equipment is a Neuroscan 64 channel MR compatible EEG system. This device has the latest software for removing the MR imaging artifacts induced on the EEG signal. With the use of ECG and pulse signals it is possible to remove the ballistocardiogram artifact. The latest version of Curry is used to analyze the EEG signals in conjunction with the fMRI determined sources. To date the device has already been successfully used is several experiments.
The 3T does not have a window like most clinical scanners. This is to reduce the amount of RF noise entering the room. The room has tested to 110dB of attenuation at the center frequency of 123 Mhz. Typical scanner manufacturer’s require 60-70 dB for clinical images. The subject is monitored with a wide angle and telephoto camera. This combination often provides a much better view than looking through a window. In addition, the images are saved to a digital video recorder and can be saved as a movie. This also serves as a safety feature to document all activities in the magnet room.
The operator also has the ability to play music or a movie to the subject during the non-functional portion of the study. This helps relax the subject and makes the time pass more comfortably. The subject is usually asked to bring their own selection, however, there are a few generation spanning selections available at the Center.
Clinical:
Northwestern Memorial Hospital (NMH) is the primary teaching hospital of NorthwesternUniversity’s MedicalSchool. In 1999, the hospital moved into a new 492-bed, two million sq. ft. inpatient and outpatient facility. The Department of Radiology contains 57 faculty, 21 fellows, and 27 residents. The Department operates a large GE Medical Systems picture archiving and communication system (PACS) to provide a film-less environment. Over 300,000 imaging studies are performed annually, of which 95% are stored, transmitted, displayed and interpreted on the PACS. There are 27 diagnostic imaging workstations in the department and another 70 throughout the rest of the facility. The Interventional Radiology section (9 physician faculty, 7 clinical fellows, 2 physician assistants) performs approximately 8,000 procedures a year at NMH in five Siemens angiography suites. Procedures include peripheral PTA/stents, embolizations, inferior vena cava filters, drainages, central venous access, and biopsies. There are currently 7 clinical MRI scanners, which perform approximately 40,000 MRI scans annually.
Computer:
CTI has two Sun image processing workstations (Leonardo, Siemens Medical Solutions) capable of performing data analysis. These are readily available for use by the PI. Each member of this project has a high-end personal computer with Microsoft Office Professional. The Department of Radiology’s Imaging Informatics Section operates a 4000 sq. ft. research laboratory. Six full-time technical staff includes 3 JAVA programmers, 1 UNIX system administrator, 1 PC administrator, and 1 web services coordinator. The section is responsible for upkeep of almost 100 personal computers and the Research workstations. The section also operates a large UNIX server and two smaller Windows NT servers that provide web, ftp, mail, and other services to the department. There is a research DICOM archive with DVD backup, and the section has developed software (DICOM) to transfer studies from the clinical PACS to the research archive, teaching files, and collaborating institutions in a secure fashion.
Other:
1.Northwestern University and Siemens Medical Solutions (Erlangen, Germany) have a research agreementto develop MRI imaging techniques. Five senior Siemens PhD scientists are on site in the MR Research Group Office Space. This arrangement allows Northwestern researchers access to Siemens’ most advanced MRI hardware and software for magnetic resonance imaging.
2. High Speed Network: NMH operates a high performance Gigabit Ethernet network. The PACS operates on its own similar Gigabit Ethernet network. The Imaging Informatics Section laboratory is connected to this network via a 45 Mb/s DS-3 circuit. The MedicalSchool is connected via a Gigabit Ethernet circuit to the OC-12 backbone of the University. NorthwesternUniversity is a charter member of the Internet II consortium, and a member of the vBNS and the Metropolitan Research and Education Network (MREN) consortia. A recent survey ranked NorthwesternUniversity as the second “most wired” campus.
Equipment List
-State-of-the-art whole-body Siemens 1.5-Tesla Espree MRI scanner (Siemens Medical
Solutions,
Erlangen, Germany)
-State-of-the-art whole-body Siemens 3.0 Tesla Trio MRI scanner (Siemens Medical
Solutions,
Erlangen, Germany)
-MR-compatible Omni-Trak 3100 MRI Vital Signs Monitoring System (Invivo
Research, Inc., Orlando, Florida). System measures heart rate, ECG, respiration, blood oxygen saturation, and CO2 monitoring.
-Spectris MR Power Injector (Medrad, Inc., Pittsburgh, Pennsylvania). Injects MR
contrast agent and saline.
-Abbott Point of Care blood analyzer (i-STAT 300, Abbott Labs, Abbott Park, Illinois).
The analyzer tests serum eGFR levels.
-Life Pak-20 Defibrillator/Monitor (Medtronic Emergency Response Systems, Inc.,
Redmond, Washington) Monitors heart rate and rhythm and has both an automated and
manual defibrillator mode.
-Ferroguard (Metrasens Ltd., Lemont, Illinois). Monitors ferromagnetic environment.
Siemens 1.5 T Espree
Neurovascular Coils:
-Head Matrix, 12 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Neck Matrix, 4 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
Cardiovascular and Body Imaging Coils:
-2 Body Matrix Coils, 6 channels (TIMS, Siemens Medical Solutions, Erlangen,
Germany)
-Spine Matrix, , channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Run Off, , (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Large and Small Flex Coils, 2 channels (Machnet, The Netherlands)
-Knee, 2 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Cardiovascular, 32 channel (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-1 set of Carotid Coils, 2 channels (Machnet, The Netherlands)
Siemens 3.0 T Trio
Neurovascular Coils:
-Head, 8 channels (Invivo Research, INC., Orlando)
-Head, 12 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Head, 32 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Neck Matrix, 4 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Spine Matrix, , (TIMS, Siemens Medical Solutions, Erlangen, Germany)
Cardiovascular and Body Imaging Coils:
-2 Body Matrix Coils, 6 channels (TIMS, Siemens Medical Solutions, Erlangen,
Germany)
-Breast, 4 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-Knee, 4 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)
-1 set of Carotid Coils, 4 channels (Invivo Research, INC., Orlando, Florida)
-Cardiovascular, 30 channels (TIMS, Siemens Medical Solutions, Erlangen, Germany)