GPU-Based Real-Time Imaging Software Suite for Medical Ultrasound

Figure 7. Real-time images of a mouse subcutaneous kidney tumor from PA Imager obtained using a 24-element 1-D CMUT array. The vasculature in the tumoris visible in the photoacoustic image.TABLE IIIEXPERIMENTAL CONDITIONS AND IMAGING RATES OF FIGS. 5-7Fig. 5 Fig. 6(a) Fig. 6(b) Fig. 7Imaging program General Imager MIP Imager MIP Imager PA ImagerProbe128-element ring CMUT array 64-element ring CMUT array 128-element ring CMUT array 24-element 1-D CMUT array(4.84-mm radius)(1.16-mm radius)(4.84-mm radius)(63-μm pitch)Probe center frequency 6.5 MHz 10 MHz 6.5 MHz 8.5 MHzImaging scheme SPA-HW 1 SPA-HW 1 SPA-HW 1 CPA 2 + PhotoacousticImaging targetTen fluorocarbon fishing wires A metal springA metal spring(150-μm thickness)(6-mm diameter)(13-mm diameter)A mouse subcutaneous tumorImaging depth 25 mm 15 mm 40 mm 15 mmImaging rate100 for ultrasound image14 104 11in frames per second10 for photoacoustic image 31 SPA-HW: Synthetic phased array imaging with Hadamard coding and aperture weighting (Norton weighting and cosine weighting)2 CPA: Classic phased array imaging3 Imaging rate for photoacoustic image is limited by the 10-Hz laser repetition rate.obtained using different targets and different probes.Experimental conditions and acquired imaging rates from theseexperiments are summarized in Table III.V. CONCLUSIONWe developed a GPU-based ultrasound imaging softwaresuite that is capable of real-time volumetric imaging witharbitrary probe geometries and various imaging schemesincluding non-conventional techniques such as syntheticbeamforming and Hadamard coding. Exploiting massive datalevelparallelism in beamforming operations, this softwaresuccessfully generated volumetric images in real-time forvarious imaging schemes. The real-time imaging wasdemonstrated using our custom CMUT probes with annular,linear, and rectangular shapes.ACKNOWLEDGMENTThis work is funded by the National Institutes of Healthunder Grants HL67647 and CA134720. We also thank Nvidiafor donating a C2070 graphics card.REFERENCES[1] Ö. Oralkan, A. S. Ergun, J. A. Johnson, U. Demirci, M. Karaman, K.Kaviani, T. H. Lee, and B. T. Khuri-Yakub, “Capacitive micromachinedultrasonic transducers: Next-generation arrays for acoustic imaging?,”IEEE Trans. Ultrason., Ferroelect., Freq. Contr., vol. 49, no. 11, pp.1596–1610, Nov. 2002.[2] J. W. Choe, Ö. Oralkan, A. Nikoozadeh, A. Bhuyan, B. C. Lee, M.Gencel, and B. T. Khuri-Yakub, “Real-time volumetric imaging systemfor CMUT arrays,” in Proc. IEEE Ultrason. Symp., pp. 1064–1067,2011.[3] J. W. Choe, Ö. Oralkan, A. Nikoozadeh, M. Gencel, D. N. Stephens, M.O’Donnell, D. J. Sahn, and B. T. Khuri-Yakub, "Volumetric real-timeimaging using a CMUT ring array," IEEE Trans. Ultrason., Ferroelect.,Freq. Contr., vol. 59, no. 6, pp. 1201–1211, Jun. 2012.[4] J. Bercoff, G. Montaldo, T. Loupas, D. Savery, F. Mézière, M. Fink, andM. Tanter, “Ultrafast compound Doppler imaging: Providing full bloodflow characterization,” IEEE Trans. Ultrason., Ferroelect., Freq. Contr.,vol. 58, no. 1, pp. 134–147, Jan. 2011.[5] J. W. Choe, A. Nikoozadeh, Ö. Oralkan, and B. T. Khuri-Yakub, "GPUbasedreal-time volumetric ultrasound image reconstruction for a ringarray," IEEE Trans. Medical Imaging, vol. 32, no. 7, pp. 1258–1264, Jul.2013.[6] A. Nikoozadeh, J. W. Choe, S. Kothapalli, A. Moini, S. S. Sanjani, A.Kamaya, Ö. Oralkan, S. S. Gambhir, and B. T. Khuri-Yakub,“Photoacousitc imaging using a 9F MicroLinear CMUT ICE catheter,”presented at the IEEE Ultrason. Symp., Dresden, Germany, Oct. 7-10,2012.