Objectives: In this study LIUS-preconditioned MSCs were implantedinto rabbit cartilage defects and the ensuing outcomes was evaluated inthe context of chondrogenic differentiation of MSCs in vivo and re-sultant defect healing.Methods: Rabbit MSCs were isolated and seeded into polyglycolicacid (PGA) scaffold. The PGA-MSCs constructs were divided into twogroups (US group and non-US group) and cultured in chondrogenicdefined media for a week. The US group received the stimulation at theintensity of 200 mW/cm2 for 10 min twice a day for 1 week. Theconstructs were then implanted into the cartilage defects that werecreated in rabbit femoral trochlea. The gross, histological and immu-nohistological analysis were made at 4, 8 and 12 week post-implanta-tion, respectively.Results: The gross finding showed that the articular cartilage defectswere filled with the repair tissue for all the groups. Histology andimmunohistochemistry however confirmed more intense and widerdistribution of cartilage specific ECM, in the US group than those innon-US-treated group.Conclusions: This study indicated that in vitro preconditioning ofrabbit MSCs can improve healing of cartilage defects that may bethrough due mostly to LIUS induced chondrogenesis of MSCs.

3624

Ultrasonographic features of various cystic lesions in theabdomen: Radiologic and pathologic correlationJun SR, Lee JY, Choi BI, Han JK, Seoul National UniversityHospital, Korea

Cystic lesions occur in almost all abdominal organs and structures, andtheir diagnosis can be challenging. Common lesions include pseudo-cyst (pancreatic or nonpancreatic), choledochal cyst, Meckel’s diver-ticulum, epithelial cysts of various organs, cystadenoma of variousorgans (biliary, pancreas), cystic lymphangioma, mucocele, intraductalpapillary mucinous tumor and so on. Rare diseases include epithelialcyst in intrapancreatic accessory spleen, cystic tumor degeneration,gastrointestinal stromal tumor, renal cell carcinoma, pancreatic cancer,neurogenic tumor, islet cell tumor), dermoid cyst, epidermoid cyst ofthe spleen, Brunner gland hamartoma, intraperitoneal bronchogeniccyst, adrenal cyst, cystic metastasis, etc. We will discuss and illustratethe ultrasonography and MDCT imaging features of these diseases. Wealso correlate radiologic findings with pathologic ones in all cases. Theunderstanding of ultrasonographic features and the radio-pathologiccorrelation of these cystic lesions facilitate us to make accurate diagnosis.

3625

Sonoporating cells for drug delivery: Effect of pulse bandwidthand duty-cycleKarshafian R, Bevan PD, Samac S, Banerjee M, Burns PN,University of Toronto, Sunnybrook Hospital, Canada; SunnybrookHospital, Canada

The combination of ultrasound and microbubbles is currently beingexploited to enhance local drug delivery and uptake. This work inves-tigates the effect of ultrasound parameters on sonoporation, the revers-ible increase in permeability of biological membranes. Suspensions ofKHT-C cells were exposed to ultrasound of varying pressures, pulselengths and duty cycles, in the presence of contrast agent microbubbles(Definity). Fluorescently labeled dextran (70 kDa) was used as apermeability marker. Flow cytometry and microscopy were used toquantify permeability and viability. The bandwidth had a significanteffect, with narrowband tone-bursts more effective at permeabilisingcell membranes. However, longer pulses also killed more cells, de-pending on the pulse repetition frequency (PRF). Our results suggestthat with a bubble concentration of 3.5% (volume-concentration), 16

cycles at 3 KHz PRF may be optimum for such permeabilization,achieving a maximum of 70 � 5% permeabilised, viable cells. Currentwork applies this finding to an in vivo model.

3626

Predictability of transvaginal ultrasonography in terms of serumestradiol level per mature follicle in controlled ovarianhyperstimulation cycles using GnRH antagonistsLee JR, Ku YH, Ku S-Y, Jee BC, Suh CS, Choi YM, Kim JG, MoonSY, Kim SH, Department of Obstetrics and Gynecology, College ofMedicine, Seoul National University, Korea; Institute ofReproductive Medicine and Population, Medical Research Center,Seoul National University, Korea

Objectives: Serum estradiol level on ovulation-triggering day duringcontrolled ovarian hyperstimulation cycles using GnRH agonists (Gn-RHa) correlates well with number of mature ovarian follicles, and isapproximately 150 to 250 pg/ml per follicle � 14 mm in diameter.However, to date, few such reference data are available for GnRHantagonist (GnRHant) cycles. We attempted to evaluate a relationshipbetween number of mature follicles and serum estradiol levels duringGnRHant cycles.Methods: On ovulation-triggering day of GnRHant (n � 97) andGnRHa (n � 102) cycles, number of follicles � 14 mm was countedusing transvaginal ultrasonography, and serum estradiol level wasmeasured using radioimmunoassay. Statistical correlation was ana-lyzed between serum estradiol levels and number of mature follicles.Results: Clinical characteristics of study subjects did not differ be-tween the two groups. Serum estradiol levels per follicle � 14 mmwere 201.9 pg/ml (r � 0.544, p � 0.001) in GnRHant cycles and 161.9pg/ml (r � 0.357, p � 0.001) in GnRHa cycles, respectively.Conclusions: Estimated serum estradiol level per mature follicle ofGnRHant cycles may be higher than that of GnRHa cycles, whenmeasured by transvaginal ultrasound on ovulation-triggering day. Weshould interpret the relationship between number of mature folliclesand serum estradiol level differently during GnRHant cycles.

3627

Myocardial tissue tracking is influenced by acute preload changein patients with end-stage renal diseaseShin M-S, Shim E-O, Chung W-J, Kang WC, Han SH, Koh KK, AhnTH, Chol I-S, Shin EK, Gachon Medical School, Gil Medical Center,Korea

Objectives: We investigated the influence of acute preload reductionon tissue Doppler imaging (TDI) data.Methods: Twenty-nine patients with end-stage renal disease werestudied by TDI and standard Doppler before and after hemodialysis.From the apical window, TDI sample volume was placed at the mitralannulus and the mid segment of anterior and posterior wall of leftventricle (LV). Tissue velocity, tissue tracking, strain and strain ratewere measured. Peak early (E) and late diastolic velocities of transmi-tral flow were measured.Results: Mean body weight change was 2.6 � 0.8 kg. LV ejectionfraction was not significantly changed after hemodialysis. Myocardialtissue tracking was decreased from 7.9 � 2.4 mm to 6.4 � 1.9 mm afterhemodialysis (p � 0.05). Peak systolic tissue velocity, strain and strainrate were not significantly different. E-velocity, early to late diastolicflow velocity ratio and peak velocity of pulmonary venous diastolicflow were significantly decreased (p � 0.05). Deceleration time ofE-wave showed increasing trend after hemodialysis.Conclusions: Tissue tracking measuring myocardial displacement areinfluenced by acute preload change. Therefore, preload should beconsidered in the interpretation of tissue velocity and tissue tracking.

P298 Ultrasound in Medicine and Biology Volume 32, Number 5S, 2006