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Elizabeth A. Krupinski, PhD Arizona Telemedicine Program. Ovitt, et al . Intravenous angiography using digital video subtraction: x-ray imaging system. AJR 135(6):1141-4, 1980.
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Elizabeth A. Krupinski, PhD Arizona Telemedicine Program
Ovitt, et al.Intravenous angiography using digital video subtraction: x-ray imaging system.AJR 135(6):1141-4, 1980. An x-ray imaging system, using digital subtraction techniques, has been developed. The system requires: (1) high output generation equipment; (2) an image intensifier capable of receiving high output exposures, 1 mR (2.58 X 10(-7) C/kg) at the face of the intensifier, without loss of either contrast or resolution; (3) a precision digital video camera; (4) processing computer with sufficient storage capacity; and (5) digital image storage. With this system it is possible to visualize the major arteries after intravenous contrast injection.
Capp et al. The digital radiology department of the future. Rad Clin N Am 23(2):349-55, 1985. The boom in microelectronics, including cost-effectiveness, has now allowed us to consider the use of these objects to store digital images. There remains much research, development, And clinical evaluation to be done in receptor technology. Further improvements in image processing, optical laser disk storage, & optical transmission and further commercial Development of display technology must take place. All of These developments are occurring simultaneously. Within 5 to 10 years, radiology departments will most likely be totally electronic, probably cost-effective, and, it is hoped, more diagnostically accurate.
Oldest established TM application • Well integrated in numerous settings • Facilitated by co-evolution PACS • Few to no reimbursement issues • Only interventional radiology currently less amenable to teleradiology applications • Little/no differences between teleradiology & on-site radiology
ACR-NEMA development DICOM • Continual updates of DICOM • Development of standards & practice guidelines that explicitly include teleradiology • http://medical.nema.org/ • http://deckard.duhs.duke.edu/~samei/tg18.htm
Key is the human-computer interface • Series of observer performance studies designed to optimize the digital reading room environment • Performance metrics • Diagnostic accuracy (ROC) • Search efficiency (eye position) • Human Visual System Modeling
Softcopy display parameters • Luminance • Calibration (tone scale) • Type of phosphor • CRT vs LCD • MTF • Viewing angle • Number of displays • Ambient lighting • Compression • Role of color P45 P104
Spatial & contrast resolution limitations require radiologists to search images. The UVF is about 2.5 deg radius. Probability of target detection falls off as a function of target eccentricity from axis of gaze.
Total viewing time shorter • Time to first hit shorter • Total time on lesion shorter • Fewer returns to lesion • Total path length shorter • Overall = more EFFICIENT
Med Student Resident Pathologist
Display & Interface 20% fixations fell outside diagnostic image
Hospital/MC • Clinics • Mobile van • Mammo • Dedicated • PET clinic • THH • UASA • Public Health • Battlefield • Hand-held
Medical Imaging Consultants -> ? • Data acquisition & archiving • RadWorks (GE) -> Siemens/Fuji • Viewing station • 35% of department’s reading volume • 25% department’s income • Reading only & reading + archiving • $/case & $/set volume
68% sites using AHSC hub for TM services use TR service • TR typically 1st service requested • 79% of sites with TR use only TR • 21% started with TR & added services • TR specialty with most volume
Time from mammography to consult with oncologist ~ 28 days • Screening mammography • Diagnostic mammography • Biopsy • Pathology processing & report • Oncology consultation • THIS IS TOO LONG!
DS3 (45 Mbps) backbone • ATM protocol • T1 (1.5 Mbps) links • 65 direct link sites • ~ 85 with affiliated • NARBHA • DOC • IHS • RT & SF applications • ~ 55 sub-specialties • Teleradiology core app.
Started in 2001 to rural sites • 7/28 telerad sites send mammo • Mostly use GE system • Directly to TBC for reading • Some archive some do not • Contracts specify 30-45 min TAT • > 26,000 telemammography
Quick Processing Milestone Medical Systems RHS-1-30 Vacuum Histoprocessor
Telepathology DMetrixTM -40 Slide Scanner System
Telepathology report sent S&F to oncologist • Oncologist connects RT videoconference to rural location • Discuss pathology results • If necessary discuss treatment options and plan of action
The Future of TR & PACS • MI = prevention, detection, diagnosis, treatment & therapy • Acquisition & display technology continually changes • Clinician shortages are not easing • Rapidly expanding types & number images • Multi-modality & fusion complimentary information sources is becoming common • Anatomy & function gross & molecular levels • Merging specialties
Clarke et al. Validation if Tumor Burden Measurements Using 3D Histopathology. In: Digital Mammography 2008. Springer-Verlag.
The Future of TR & PACS • Image Display, Analysis & Processing are key links in the imaging chain • Need to present data to the clinician in the most efficient & informative manner • Taking into account perceptual & cognitive capabilities of human observer • Ultimate goal = facilitate decision-making process & enhance patient care • Related goal = improve workflow & the reading environment
Stereo vs Traditional • Az 0.85 to 0.94 • 23% increase TPs • 105% increase calcs • 46% decrease FPs Getty et al. Stereoscopic Digital Mammography: Improved Accuracy of Lesion Detection in Breast Cancer Screening. In: Digital Mammography 2008. Springer-Verlag.
50 DR chest images (PA) : 1/2 solitary pulmonary nodule verified CT; 1/2 nodule free • 6 radiologists (3 sr residents, 3 board-certified) • 3MP Barco color medical-grade display (BarcoCoronis MDCC-3120-DL) vs COTS color 2MP monitor (Dell 2405) • Calibrated (DICOM GSDF ) to luminance corresponding to backlight aging 1-year time • Max Barco 500 cd/m2 min 0.77 cd/m2 • Max Dell COTS 342 cd/m2 min 0.376 cd/m2
Color vs Color F = 4.1496, p = 0.0471 Sensitivity = 0.91 vs 0.86 Specificity = 0.93 vs 0.92
Color vs Color F = 3.38, p = 0.067
Color vs Color No significant differences TN significantly different