ISSN:1053-1807    

DOI:10.1002/jmri.1880080102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

ISSN:1053-1807    

DOI:10.1002/jmri.1880080103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

ISSN:1053-1807    

DOI:10.1002/jmri.1880080104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractSteadfast progress has been made from biopsy to surgery with interventional MRI (iMRI). Such image‐guided interventions require specialized instrumentation due to the unusual elements of the MR environment. Suppliers/manufacturers of MR‐compatible instrumentation were few in 1994, but now there are more than 50. We present fundamental issues of MR compatibility and a list of known suppliers/manufactur

ISSN:1053-1807    

DOI:10.1002/jmri.1880080105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

ISSN:1053-1807    

DOI:10.1002/jmri.1880080106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe MR Section of The National Electrical Manufacturers Association (NEMA), in response to a request from the Food&Drug Administration (FDA), recently issued a position paper to address generic issues related to the compatibility of accessory equipment produced by third party equipment manufacturers or MR equipment users and intended to be used in conjunction with MR equipment or within the MR scanning room. The recommendations concern scanning accessories, such as radiofrequency (RF) coils, patient monitoring equipment and injectors, as well as patient comfort accessories and positioning devices. The following issues related to safety performance are discussed: (a) the interaction of the equipment with the MR scanner, (b) interactions of the MR scanner with the equipment, and (c) potential safety hazards for patients and staff that can be posed by accessory equipment in the MR scan environment. The recommendations are based on combined input from NEMA member companies who manufacture MR systems and MR accessories and are presented for consideration in the design of MR accessory products and incorporation of these concepts into testing plans to ensure MR compatibility of third party devices.

ISSN:1053-1807    

DOI:10.1002/jmri.1880080107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe use of MRI to guide and monitor interventional procedures requires the merging of surgical and MRI environments. The ideal magnet shape for homogeneity and efficiency is spherical, but this design provides no access. Opening the sphere to provide both patient and surgeon access suggests cylindrical or biplanar magnets. Cylindrical magnets have poor surgical access but provide good imaging capabilities, which can be used in conjunction with a neighboring but distinct surgical environment. Biplanar magnets provide more and better approaches to the patient, but generally with lower field strength. Vertical biplanar systems allows surgical approaches from above but reduce the access of support staff to the patient. A hybrid magnet design, which combines the benefits of both cylindrical and biplanar magnets, can provide increased access with simultaneous approach from two sides of the patient. Application‐specific magnets can target a smaller region, leading to compact magnet designs that greatly expand access for both surgical intervention as well as patient support. As the field of interventional MRI matures, the suitability of each design to specific applications will be better understood, leading to more integrated system designs tailored to the needs of imageguided therap

ISSN:1053-1807    

DOI:10.1002/jmri.1880080108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

ISSN:1053-1807    

DOI:10.1002/jmri.1880080109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractInterventional MR (IMR) machines have produced unique opportunities for image‐guided surgery. The open configuration design and fast pulse sequences allow intraoperative scanning to monitor procedures. This study was undertaken to assess the potential use of IMR for image‐guided surgery. Benign breast lesion excision was chosen as an uncomplicated surgical model. Ten female patients with known benign tumors underwent excision biopsy under general anesthesia in a Signa SP10 .5‐T IMR machine (General Electric Medical Systems, Milwaukee, WI). Lesions were localized with precontrast and postcontrast (intravenous gadolinium‐diethylenetriamine pentaacetic acid, .2 mmol/kg) fast multiplanar spoiled gradient‐recalled acquisition in the steady state (GRASS) sequences. Preoperative “real‐time” fast gradient‐recalled sequences were also obtained using the Flashpoint (General Electric Medical Systems, Milwaukee, WI) tracker device. The maximum dimensions of each lesion were measured from the resulting images. Excision was performed using titanium instruments and an ultrasonically activated scalpel. Intraoperative real‐time scanning demonstrated the resection margin and confirmed complete excision. The maximum dimensions of the macroscopic specimens were compared with those from the MR images. All tumors were visualized with the Signa scanner and real‐time imaging and the images were enhanced after intravenous contrast. Maximum dimensions on histologic examination were not significantly different from those measured from Signa (P>.17) or real‐time images (P>.4). There was no significant difference between lesion size from Signa and real‐time images (P>.25). All postprocedure scans demonstrated complete excision. There were six fibroadenomas, two foci of sclerosing adenosis, one area of fibrocystic disease, and one schwannoma. Intraoperative MR scanning reliably identifies palpable breast tumors and can accurately guide surgical excision. Further work using MR guidance can now be performed in oth

ISSN:1053-1807    

DOI:10.1002/jmri.1880080110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to predict diameters of lesions induced by laser‐induced thermotherapy (LITT) of benign prostatic hyperplasia (BPH) from MRI signal/tissue temperature correlations during on‐line monitoring with a temperature‐sensitive fast low‐angle shot (FLASH) sequence. Twenty LITT procedures with Nd:YAG (1,064 nm) and diode (830 nm) lasers were monitored on line with a T1‐weighted FLASH sequence at 1.5 Tesla. Interstitial prostate temperature (T) was measured on line in 10 LITT procedures and laser energy deposition in 12. Slopes of linear regression curves for signal intensity (SI) over T were applied to determine SI at 60°C to estimate diameters of intraprostatic LITT lesions. Diameters of unperfused LITT lesion cores in contrast‐enhanced T1‐weighted images served as gold standards. Linear regression curves with an average slope of −.54% SI/°C were obtained in 17 LITT procedures. Correlation coefficients werer= .92−.95 for SI/T and SI/energy deposition. Baseline variation of SI at body temperature was ±3.9%, corresponding to ±7°C. Prediction of size (13 lesions) from on‐line FLASH imaging was correct in 10 of 13, whereas 3 lesions were overestimated. Prediction of LITT lesion diameters from on‐line MRI monitoring is possible with a temperature‐sensitive FLASH sequence in the prostate. Accuracy may suffice to assign target regions of interest to tissue locations to b

ISSN:1053-1807    

DOI:10.1002/jmri.1880080111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1998

数据来源: WILEY