Abstracts
S36
EFFE4XIVE K-D,STR,B”TION
DENSlTY ESTIMATORS BASEDON THE : INTEREST OF THE UIW ORDER MOMENTS
M., LebxtreM., PatatF., Pwrc&x L. OIP“ltrasaa , EA2 Ill2 -cm srcbmneau - KUJRS
TEXTURE ANALYSIS OF ECHO-ENWSCOPIC IMAGES OF THE PANCREAS. Fmn@se LBFEBVRE’, FrCdCric PRAT.*, semia ZIDI”, Abdehziz AMICHI’, Pascal LAUGIBR’, Genevi&ve BBRGBR* ‘-he d’lmagmiePmmhiqw, URA CNRS 14%. Fmia, France. **Service&G
echogsnicity. These &an& A mbinly linked to the &te& dwact&tics and to the ulhasmic beam charactaistia.
structure
qprm& ha9 been to resider an t3timatm farnil; of the &ktive density based on superior ads mamentP ofthe K-distribution. ln ada to improve spatial re?&ticm of the estimate, ve su@est to extmd this EDEs family to &imatm Lwed on low and haaicaal order mcmcnu. Simulations show kacr bias and buta variance of these last ED!& On the experimental side, mcaswcmer4s were pcrfcaned in hanogcnaxls hmms having the same smrtural morphology but diffsent pore size and massdmsity.Kewlts mx in gwd sgrraoslt with thoseban rimulaticms and
confirm that, h gmd e.x@m& kditims, the dfstive dmsity can be considacdas a relevantMd us&l smrnm punmeter.Finally,preliminaryinvum measmenta are intmdwed.
paihned
on shop febl lung with several degea of maturity
VIBRATIONAL DOPPLER IMAGINGt A POTRNTIAL NEW METHOD OF SONO-ELAS’IOGRAPHY UN. G Sherat, PhD. Advmced Developmnt Laboratory. Dissonics Vii Clara California USA
Ultrasound, Santa
OBJECTNFS: To develop and evaluate vibrational Doppler +gi”g (VDI) as a new method of visualizing the elastic snd medvuuca resonaacc propenies of different tissues. MFXHODS: A palpable variable-frequency audio vibmtio” (50-m Hz) was applied to the skin through a” audio tmnsducer attxkd side-by-side with s conventional ultrasound linear array transducer. Ukmsonic imnging was performed with Gateway fx (Diasonics) and System Five fvingmed) ultrasound scanners using power and varianw Doppler imaging. Tissue nkkking phantoms of varying aegrrcS of hardness and the extremities, female breasts, and abdomens of 6 healthy volunteexs wm scanned. RESULTS: In &emelastic phantoms VDI trnAy Le,; higher Doppler amplitude in soft reglons. phantoms VDI demonstrated a”@ & variations comeI@+ with echogenicity. Overall VDI image brightness peaked at a uni UC vtbmtmn tkquency for each tissue, awIly within the range 150-250 R z. I” soft tissue, the layers of skin, subcotenwus fat, aad muscle always exhibited diffettmt levels of brightness in VDI. Mwy “on-pelpeble rcpion~, “ot discernable in 12.MHz B-scan, were easily visible in VDI. CONCLUSIONS: Further stodies are aimed at dekmking the precise mechanicalproperties beii imaged by VDI. VDI has pok”tiel h detecting subtle transitions in tissue chars&r or &echoic massesi” sofi ~&UC.
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The sensitivity of visual intaplaation of endosonographic images of thepmmasdoesnotexwed7O-EO%.Improvcmentsarenecdedto . . dwmnwtecanccrf?ompmwm&is.Theoseoftextwe8malysisfor the tissue classi6cntion fium endwwpic ulhasoaic images of the panaeas was evaluated. S&y-one B-scan images were aqoired ~43peticnts~1normalcascs,11withchronicpanaeatitia11 WithCJl”G%)USi”gthCslmKand the smle mnpIIIwti0” and aquisitio” psrsmctas. The images wwe digitized for wlysis duriag the craminatio”. For each of the ROIs man&y wmcted, 60 I#nrrmctcrs issued from the grey-level disaibutiom, the g&eve1 cwwurrence matrix and the m-level mnle”gtb hktogmm were co”lputcd for tis.¶le cbwificatio”. Alwlysis of verlance showed that atleasto”qroopdifferedfm”lthehwothersfors9pem”wem (p4.05). The Bonfenuni multiple wmp&son h~proved~ alltbepairswuesig”itica”tlydlfkmtforI6pscemetcrs.Ali”ear discrimiMtiollanalysisusing3panunetm:selectsdbyasIepwisc regression prwedure led to a good cksifi&o” rate into c811ce~ vmsus “o*-wnwr cases of 8%. Our results suggest that textore analysis is likely to improve discrimination of cawer fknn “o”cancer tissue of the ps.“crea9.
CYCLIC VARlATION IN REFLECTIVITY CARDIOMYOCYTES
OF ISOLATED
A.F.W. van der Steen, M. Riehle, J Bereiter I-I&. Cinematic Cell Research Group, Biozentrmn J.W. Goethe University Frmkfiut Germatty, Thorax Centre Erasmus University Rotkrdwn The Netherlands, Interuniversity Cardiology Institute of the Netherlands. Cyclic variation of myocudial integrated backscatter (IB) has been studied extensively. In nomul myocardiun, there is en inverse relationship b&wee” wall thickeoing and IB, that swmi”s in e variety of pathological conditions. A ftmdune”tel explanation for this phenomenotl is still not found. To gain more insight, the influence of contraction on reflectivity is measuredat a cellular level in this shkiy. Adult rat myocytes have ken is&ted, seeded011tissoe culture dishes, coated with CellTak and the” x&if&d at 25g to e”he”ce attaekt. Relaxation was achieved by adding potessi~. Contmctio” was achiewd by add@ the calcium ionophore iommyck This umtmction was “either isotonic, IKK isometric, like in life myowdiun. Refkctlvity hasbeenasseuedusi”gacousticmicroscopyat1.OGHz~~ relaxation and co”kactio” in 4 myocytes. Avemge contraction was 7.5 f 2.5 %, and reflwtivity ind by 26 f 5 %. In the inmges it can be see” that myofibrils are probably the responsible scatterers.On contrition the cells, and the myofibrils and &ease theii diametn. Since these myofibrils are mulla then the wevele”gth of the applied oltiond, one would eq+ an increaw in reflectivity. This apes wth our experiments, however contradicts with the obsavations in viva at lower kqoencies.