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This paper presents an iterative image reconstruction method for radial encodings in MRI based on a total variation (TV) regularization. The algebraic reconstruction method combined with total variation regularization (ART_TV) is implemented with a regularization parameter specifying the weight of the TV term in the optimization process. We used numerical simulations of a Shepp-Logan phantom, as well as experimental imaging of a phantom that included a rectangular-wave chart, to evaluate the performance of ART_TV, and to compare it with that of the Fourier transform (FT) method. The trade-off between spatial resolution and signal-to-noise ratio (SNR) was investigated for different values of the regularization parameter by experiments on a phantom and a commercially available MRI system. ART_TV was inferior to the FT with respect to the evaluation of the modulation transfer function (MTF), especially at high frequencies; however, it outperformed the FT with regard to the SNR. In accordance with the results of SNR measurement, visual impression suggested that the image quality of ART_TV was better than that of the FT for reconstruction of a noisy image of a kiwi fruit. In conclusion, ART_TV provides radial MRI with improved image quality for low-SNR data; however, the regularization parameter in ART_TV is a critical factor for obtaining improvement over the FT.

In follow-up brain magnetic resonance imaging (MRI), precise reproducibility of the scan prescription is important so that over- or underestimating changes in volumes of clinical interest is prevented. (The scan prescription is defined as the location and orientation of the head with respect to the scan planes of the three-dimensional MRI matrix.) In this study, the misregistration between the original and a second scan was calculated in the case of both manual positioning and automatic positioning. These calculations were carried out both for a healthy volunteer scanned repeatedly and, in a retrospective study, for 225 patients who had an original and at least one follow-up scan. The effects of the scan operator being the same for both scans or being different were also examined. A commercially available 1.5 Tesla MRI system and a six-element head-array coil were employed in all of the imaging. The reproducibility of the scan prescription was determined by the registration of the original scan image to the follow-up scan image by use of the Fourier phase correlation method. Our results showed that (1) the reproducibility by automatic positioning was superior to that by manual positioning (p0.05), and (2) there was no significant difference in the results between when the operator was the same or different (p0.05). We conclude that, in follow-up brain MRI, automatic positioning should be used, because manual positioning decreases the reproducibility of the scan prescription even if the same operator performs the second scan.

Purpose: To assess the ability of magnetic resonance imaging (MRI) to depict the semicircular canals of the inner ear by comparing results from the sampling perfection with application-optimized contrasts by using different flip angle evolutions (SPACE) sequence with those from the true free induction with steady precession (TrueFISP) sequence. Materials and Methods: A 1.5-T MRI system was used to perform an in vivo study of 10 healthy volunteers and 17 patients. A three-point visual score was employed for assessing the depiction of the semicircular canals and facial and vestibulocochlear nerves and the contrast-to-noise ratio (CNR) was computed for the vestibule and pons on images with the SPACE and TrueFIPS sequences. Results: There were no susceptibility artifact-related filling defects with the SPACE sequence. However, the TrueFISP sequence showed filling defects for at least one semicircular canal on both sides in seven cases for healthy subjects and in 10 cases for patients. The CNR with the SPACE sequence was significantly higher than with the TrueFISP sequence (P < 0.05). There was no statistically significant difference in depicting the facial and the vestibulocochlear nerves (P = 0.32). Conclusion: For the depiction of the semicircular canal, the SPACE sequence is superior to the TrueFISP sequence. J. Magn. Reson. Imaging 2013;37:652–659. © 2012 Wiley Periodicals, Inc.

Heart transplant recipients undergo annual screening of early-stage cardiac allograft vasculopathy (CAV) by invasive coronary flow reserve (CFR) measurement. We compared the sensitivity for CAV detection between the CFR measurement and noninvasive magnetic resonance (MR) assessment of left ventricular (LV) diastolic function. In 46 asymptomatic recipients (29 men, aged 35.2 ± 16.1 years) 7.9 ± 4.3 years after transplantation, we measured LV peak filling rate (PFR) using cine MR and CFR in the left anterior descending artery by Doppler guidewire; classified recipients of class 0-2 as negative for CAV and class 3-4, positive, according to Stanford classification assessed by IVUS; compared those values between the 2 groups; and calculated receiver operating characteristic curve in the relationship between PFR value and CAV. We classified 20 recipients (43%) positive and 26 (57%) negative for CAV. Although there was no significant difference in CFR value, the PFR value was significantly lower in the positive (3.54 ± 0.84 EDV/s) than in negative group (4.39 ± 0.85 EDV/s, P = 0.002). Area under the curve was 0.78, and the sensitivity was 78% and specificity, 61%, when PFR cut-off value was 4.20. MR PFR measurement provides noninvasive prediction of CAV, preceding impaired CFR in asymptomatic recipients.

Purpose: To compare the image qualities of unenhanced electrocardiographically (ECG)-gated fast spin-echo magnetic resonance digital subtraction angiography (MRDSA) using a short echo-spacing three-dimensional (3D) sequence, known as sampling perfection with application-optimized contrasts using different flip angle evolutions (SPACE), and the conventional half-Fourier single-shot turbo spin-echo (HASTE) sequence. Materials and Methods: Unenhanced ECG-gated MRDSA using SPACE and HASTE of the femoral arteries were prospectively acquired in 13 healthy volunteers at 1.5 Tesla (T) MRI. Sequential frontal maximum-intensity-projection images produced by subtracting each of 10 systolic images from a diastolic image were evaluated quantitatively using paired t-test and qualitatively by two blinded radiologists using the Mann-Whitney U-test. Results: Quantitatively, relative contrast against the background, contour sharpness index, and slope of the sequential signal changes of the superficial femoral artery of MRDSA using SPACE were significantly better than those of HASTE (P = 0.005, P = 0.001, and P < 0.0001, respectively). Qualitatively, the overall subjective image quality and sequential appearance changes of MRDSA using SPACE were significantly better than those of HASTE (P < 0.0001 and P < 0.0001, respectively). Conclusion: Unenhanced ECG-gated fast spin-echo MRDSA using SPACE produces increments in signal intensity, which reflect arterial pulse wave transmission, more clearly than the conventional HASTE sequence. J. Magn. Reson. Imaging 2011;. © 2011 Wiley-Liss, Inc.

Alongside the two conventional unenhanced magnetic resonance (MR) angiographic techniques, namely time-of-flight and phase-contrast MR angiography, several novel techniques have since been developed, including electrocardiograph (ECG)-gated fast spin echo (FSE), steady-state free precession (SSFP), and arterial spin labeling. These techniques are increasingly being used to avoid severe complications caused by contrast materials, such as iodinated contrast material-induced nephropathy and gadolinium-induced nephrogenic systemic fibrosis. However, image acquisition and interpretation with these techniques are more complicated than with contrast-enhanced MR angiography because of numerous types of artifacts. Appropriate use of these techniques can allow diagnosis of vascular diseases in patients with chronic kidney disease without using contrast materials. For example, time-of-flight angiography is the main technique for evaluating intracranial arteries. Phase-contrast imaging is increasingly being used for physiologic evaluation rather than morphologic evaluation. Meanwhile, ECG-gated FSE MR angiography can show peripheral arteries in more detail. SSFP MR angiography with or without arterial spin labeling can provide high-resolution images of blood vessels including renal arteries, the aorta, and coronary arteries. Black-blood imaging is also used to evaluate vessel walls and intravascular abnormalities including plaque, dissection, and thrombi. The authors review the principles of the currently available unenhanced MR angiographic techniques, along with their advantages and limitations, and describe their clinical applications. This article should help readers select the most appropriate unenhanced MR angiographic technique to assess vascular diseases in patients with chronic kidney disease. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.312105075/-/DC1.

Purpose We aimed to evaluate flow patterns in the superior vena cava (SVC) and azygos vein confluence with cine phase-contrast magnetic resonance imaging with consideration for the role played by the azygos arch valves. Materials and Methods Two-dimensional cine phase-contrast magnetic resonance images of the SVC and azygos vein confluence were prospectively acquired in 10 healthy volunteers. Flow directions during the cardiac cycle were evaluated quantitatively using sequential flow profile graphs obtained from each orthogonal image and affirmed visually by two radiologists from the oblique sagittal cine images. Results Although the blood in the SVC and azygos vein confluence had an afferent flow during the systolic phase, a slight temporal efferent flow during the diastolic phase was quantitatively observed in all cases. Flow in the SVC can also be confirmed visually. The average velocity, average maximum afferent velocity during the systolic phase and average maximum efferent velocity during the diastolic phase of the SVC were 8.7±2.4, 19.9±3.7 and −1.0±3.2 cm/s, respectively; for the azygos vein confluence, these values were 2.2±1.5, 7.1±2.6 and −1.5±1.1 cm/s, respectively. Conclusion We verified that a slight temporal efferent flow exists in the SVC and azygos vein confluence during the diastolic phase, which suggests that the usual role of the azygos arch valves is to prevent this physiological retrograde flow.

We compared the accuracy of magnetic resonance imaging (MRI) measurements of pulsatile flow velocity in a small tube phantom using different spatial factors versus those obtained by intraluminal Doppler guidewire examination (as reference).We generated pulsatile flow velocities averaging about 20-290 cm/sec in a tube of 4 mm diameter; we performed phase-contrast cine MRI on pixels measuring 1.00(2)-2.50(2) mm(2). We quantified spatial peak flow velocities of a single pixel and a cluster of five pixels and spatial mean velocities within regions of interest enclosing the entire lumen in the phantom's cross-section. Finally, we compared the measurements of temporally mean and maximum flow velocity with the Doppler measurements.Linear correlation was excellent between both measurements of spatial peak flow velocities in one pixel. The highest spatial resolution using spatial peak flow velocities of a single pixel allowed the most accurate MRI measurements of both temporally mean and maximum pulsatile flow velocity (r = 0.97 and 0.99, respectively: MRI measurement = 0.95x + 8.9 and 0.88x + 24.0 cm/s, respectively). Otherwise, MRI measurements were significantly underestimated at lower spatial resolutions.High spatial resolution allowed accurate MRI measurement of temporally mean and maximum pulsatile flow velocity at spatial peak velocities of one pixel.

Purpose To confirm the superiority of the navigator-triggered prospective acquisition correction (PACE) technique over the conventional respiratory-triggered (RESP) technique, something that has been perceived experimentally but without definite evidence, for free-breathing three-dimensional (3D) magnetic resonance cholangiopancreatography (MRCP) using healthy volunteers. Materials and Methods Free-breathing 3D turbo spin-echo MRCP using both PACE and RESP techniques were prospectively performed on 25 healthy volunteers. Quantitative analyses of acquisition time, signal-to-noise ratio, contrast-to-noise ratio, and contour sharpness index of each segment of the pancreaticobiliary tree were compared using the paired t-test. Qualitative analyses on a five-point scale (1, excellent; 5, poor) scored by two independent radiologists were compared using the Wilcoxon signed-rank test. Results The subjective image quality and contour sharpness index of each segment of the PACE technique were found to be significantly better than those for RESP (P < 0.05). No significant difference was observed with regard to signal-to-noise and contrast-to-noise ratios except for the pancreatic duct. No significant difference in acquisition times between PACE and RESP techniques was observed. Conclusion We confirmed the superiority of the image quality of the PACE technique compared to conventional RESP technique for free-breathing 3D MRCP in healthy volunteers. J. Magn. Reson. Imaging 2008;28:673–677. © 2008 Wiley-Liss, Inc.

The circadian clock, regulating hormonal secretion and metabolisms in accordance with the environmental light–dark cycle, resides in almost all peripheral tissues as well as in the superchiasmatic nucleus. Clock gene expression has been found to be noncyclic during spermatogenesis and the differentiation of thymocytes. However, currently little is known about how cell differentiation could affect circadian clockwork. We performed this study using the in vitro real-time oscillation monitoring system to examine the clockwork in several types of differentiating cells originated from reproductive tissues of transgenic rats (constructed with Period gene 2 (Per2) promoter-destabilized luciferase reporter gene). After treatment with dexamethasone (DXM), persistent oscillation of Per2 expression was observed in both gonadotropin-induced and pregnant ovarian luteal cells, proliferative uterine stromal cells (USCs), and nondifferentiating testicular interstitial cells, with a cyclic period of ~24 h. In contrast to these cell types, only one cycle of oscillation was sustained in granulosa cells undergoing differentiation. Additionally, Per2 oscillation was irregular in USCs undergoing decidualization induced by medroxyprogesterone acetate plus N6, 2-O-dibutyryl adenosine 3′:5′-cyclic monophosphate. Furthermore, no oscillation of Per2 expression was evoked by DXM in Leydig cells and thymocytes. In conclusion, the present study characterized the oscillation of Per2 gene expression in several types of ovarian, uterine, and testicular cells, and it is strongly suggested that circadian clockwork is affected during cellular differentiation.

The circadian clock is responsible for the generation of circadian rhythms in hormonal secretion and metabolism. These peripheral clocks could be reset by various cues in order to adapt to environmental variations. The ovary can be characterized as having highly dynamic physiology regulated by gonadotropins. Here, we aimed to address the status of circadian clock in the ovary, and to explore how gonadotropins could regulate clockwork in granulosa cells (GCs). To this end, we mainly utilized the immunohistochemistry, RT-PCR, and real-time monitoring of gene expression methods. PER1 protein was constantly abundant across the daily cycle in the GCs of immature ovaries. In contrast, PER1 protein level was obviously cyclic through the circadian cycle in the luteal cells of pubertal ovaries. In addition, both FSH and LH induced Per1 expression in cultured immature and mature GCs, respectively. The promoter analysis revealed that the Per1 expression was mediated by the cAMP response element binding protein. In cultured transgenic GCs, both FSH and LH also induced the circadian oscillation of Per2. However, the Per2 oscillation promoted by FSH quickly dampened within only one cycle, whereas the Per2 oscillation promoted by LH was persistently maintained. Collectively, these findings strongly suggest that both FSH and LH play an important role in regulating circadian clock in the ovary; however, they might exert differential actions on the clockwork in vivo due to each specific role within ovarian physiology.

PURPOSE To elucidate the causes of aliasing artifacts with the BLADE technique and clarify the effective suppression methods. MATERIALS AND METHODS We separately observed the aliasing artifacts of BLADE from features inside and then outside the defined field-of-view (FOV) using phantom studies. The effectiveness of suppressing them with phase oversampling (POS) and presaturation pulses (SAT) was evaluated. Finally, our observations were confirmed for a healthy volunteer. RESULTS Characteristic aliasing artifacts were observed from both inside and outside the FOV. Those from inside the FOV were sufficiently suppressed by using a POS of 25%, considering the acquisition time prolongation. Those from outside the FOV were nearly suppressed using SAT outside the FOV without selecting needless receiver coils. Aliasing artifacts on the coronal images of the head and neck with a healthy volunteer were completely suppressed by a combination of using a POS of 25% and using SAT on all four sides outside the FOV. CONCLUSION The characteristic aliasing artifacts of BLADE are caused from both inside and outside the defined FOV. They can be effectively suppressed by a combination of using a POS of 25% and using SAT on all four sides outside the FOV.

VPS (蒸気相はんだ付け) 装置のリフロー工程および予熱工程における酸化問題を検討した。パーフルオロトリペンチルアミン (PFTPA) の蒸気中で銅箔を1時間加熱したが, 酸化による変色はまったくなく, 表面の酸化物の増加も検出されなかった。PFTPAの蒸気密度が非常に大きいことや, 沸騰している系の蒸気層中では蒸留の原理が働いていることから, VPS蒸気相内の酸素濃度はきわめて小さく, ゼロに近いと結論した。したがってVPSリフロー時の酸化は同様にゼロに近いと考えられる。他方, 大気中で赤外線ヒータにより行われる予熱工程での銅板の酸化をAES分析で検討した。銅板表面には, ブランク試料においても厚さ約50の酸素濃度の高い層が存在し, またピーク温度170℃, 1分の予熱を行うと, その層の厚さが約20%増加することを見出した。実用的には予熱ピーク温度は165℃以下に抑えられており, VPS装置の予熱における銅箔の酸化は軽微であると推論された。少量の金属酸化物はフラックスにより除去されることを考慮すれば, 全体として, VPS装置における酸化の影響は小さいと結論される。

Purpose: To evaluate whether perfusion fraction (PF) calculated with diffusion-weighted magnetic resonance imaging (MRI) predicts the presence of blood supply in ovarian masses. Materials and Methods: PFs of 92 ovarian lesions in 53 patients administered gadolinium were retrospectively calculated with diffusion-weighted images at b-values of 0, 500, and 1000 sec/mm2. PFs were compared between ovarian lesions, except for fat, with (n = 21) or without contrast enhancement (n = 57), using Student's t-test and receiver operating characteristics (ROC) curve analysis. Lesion enhancement rates of contrast-enhanced images at 30 and 180 seconds after gadolinium injection (ER30sec and ER180sec) and PFs were compared using Pearson's correlation coefficient. Results: PFs of the lesions with contrast enhancement were significantly higher than those without contrast enhancement (0.22 ± 0.09 and 0.02 ± 0.08, respectively, P < 0.0001). The ROC curve identified the best cutoff point for PF at 0.135 (95.2% sensitivity and 94.7% specificity) as a predictor of the contrast enhancement effect. The area under the ROC curve was 0.984. PF correlated moderately with ER30sec (0.62, y = 0.13x + 0.04, P < 0.0001) and ER180sec (0.74, y = 0.13x + 0.03, P < 0.0001). Conclusion: PF calculated with diffusion-weighted images can potentially predict blood supply in ovarian masses. J. Magn. Reson. Imaging 2011. © 2011 Wiley Periodicals, Inc.

Cardiac allograft vasculopathy (CAV) is a major late complication in heart transplant recipients, graded based on intravascular ultrasound (IVUS), and accelerates left ventricular (LV) diastolic dysfunction. We investigated the clinical feasibility of using magnetic resonance (MR) to assess LV diastolic dysfunction noninvasively in transplant recipients. Thirty-eight asymptomatic recipients (25 men, 37.2 ± 14.9 years) underwent both IVUS and cardiac MR. Based on IVUS, we divided the individuals into 2 groups using Stanford classification to categorize CAV development as either nonsignificant or advanced. We measured LV peak filling rate (PFR) and systolic function parameters, including LV ejection fraction (EF), stroke volume (SV), and cardiac output (CO) using cine MR; compared those values between groups; calculated receiver operating characteristic curve in the relationship between PFR value and CAV; and assessed myocardial late gadolinium enhancement (LGE) on contrast-enhanced MR. We classified CAV as advanced in 20 patients (53%) and nonsignificant in 18 (47%). LV EF, SV, and CO values were not significantly different. PFR was significantly lower in the advanced (3.63 ± 0.90 EDV/s) than nonsignificant group (4.43 ± 0.84 EDV/s, P = 0.01). The area under the curve was 0.76. We observed no myocardial LGE. MR measurement of PFR may permit noninvasive assessment of diastolic dysfunction associated with CAV before LV systolic dysfunction and myocardial infarction or scar formation develop.

We compared the image quality of SPACE (sampling perfection with application optimized contrasts using different flip angle evolutions) and conventional 3D turbo spin echo (TSE) magnetic resonance cholangiopancreatography (MRCP) at 1.5 tesla with regard to difference in echo spacing.Twenty healthy volunteers prospectively underwent navigator-triggered SPACE and 3D TSE MRCP at 1.5T with identical parameters, except for echo spacing. Quantitative analyses of signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), relative contrast, and contour sharpness index of each segment of the pancreaticobiliary tree were compared using paired t-tests. Qualitative analyses on a 5-point scale (1, excellent; 5, poor) scored by 2 independent radiologists were compared using Wilcoxon signed-rank test.The SNR, CNR, and contour sharpness index of each segment were significantly better for the SPACE sequence than 3D TSE (P0.05). Relative contrast and subjective image quality were not significantly different (P0.05).We verified SPACE MRCP quantitatively superior to conventional 3D TSE MRCP at 1.5T as a result of shortening of echo spacing.

The aim of this study was to compare prospectively the image quality of magnetic resonance cholangiopancreatography (MRCP) using manganese chloride tetrahydrate (Bothdel Oral Solution 10) (MCT), a new negative oral contrast agent; ferric ammonium citrate (FerriSeltz powder 20%) (FAC); and no agent.MRCP images (TE 970 ms) of patients administered MCT (n = 19) or FAC (n = 20) at random, and 18 patients without an agent were evaluated. The subjective image quality of the overall, extrahepatic bile duct, and pancreatic duct and the degree of elimination of gastrointestinal fluid scored by two radiologists blinded to information regarding the agent were compared using Mann-Whitney's U-test.The degrees of elimination of gastroduodenal fluid of MCT and FAC were significantly better than those without an agent (P0.01 and P0.01). The subjective image quality of MCT of the overall and extrahepatic bile duct were significantly better, although no significant differences for FAC were observed compared with those without an agent (P0.01 and P = 0.21, P = 0.02 and P = 0.16). There were no significant differences for the pancreatic duct (P = 0.12 and P = 0.19), nor were there any significant differences in the evaluations between MCT and FAC (P = 0.19-0.98).MCT has shown performance comparable to that of conventional FAC in terms of pancreatic and biliary depiction and safety.

The circadian oscillator is generated within the suprachiasmatic nuclei and synchronizes circadian clocks in numerous peripheral tissues. The molecular basis is composed of a number of genes and proteins that form transcriptional and translational feedback loops. Such molecular oscillators are also operative in peripheral tissues, including in the uterus. Although ovarian steroids regulate the function of uterine endometrial stromal cells, the modulation of ovarian steroids on the circadian rhythms remains unknown. Here we investigate the possibility that estradiol (E2) and progesterone (P4) modulate the circadian oscillator of the stromal cells. The study using transgenic rats constructed with Period 2 (Per2) promoter-destabilized luciferase (Per2-dLuc) gene, with the real-time monitoring system of Per2-dLuc oscillation. The stromal cells displayed constant Per2-dLuc oscillation after treatment with dexamethasone, suggesting that the circadian oscillator is operative. However, the circadian oscillator was disrupted by in vivo administration of human chorionic gonadotropin (hCG) following equine chorionic gonadotropin (eCG), although it was altered into a rhythmic pattern 4 days later following hCG. Chronic treatment with P4 induced constant Per2-dLuc oscillation in the stromal cells from eCG-treated immature and pregnant rats, whereas E2 did not promote such a rhythmic Per2-dLuc oscillation. Collectively, P4 synchronizes the circadian oscillator of the uterus endometrial stromal cells through transcriptional and translational feedback loops of the clockwork system.

We examined the spatial factors influencing magnetic resonance (MR) flow velocity measurements in a small tube phantom and used the same measurements obtained with an intraluminal Doppler guidewire as reference. We generated constant flow velocities from approximately 40 to 370 cm/s in a tube 4 mm in diameter. We then performed segmented k-space, phase-contrast cine-MR imaging to quantify spatial peak flow velocities of one pixel and of five adjacent pixels as well as spatial mean velocities within regions of interest in a cross section of the phantom. Pixel dimensions ranged from 1.00 × 1.00 mm to 2.50 × 2.50 mm. We compared the MR measurements with the temporally averaged Doppler spectral peak velocities. For one pixel (r > 0.99: MR flow velocity for pixel dimension 1.00 × 1.00 mm = 1.03x + 9.8 cm/s), the linear correlation was excellent between flow velocities by MR and Doppler guidewire methods. However, for the five adjacent pixels, MR measurements were significantly underestimated using pixels 1.25 × 1.25 mm to 2.50 × 2.50 mm and for mean velocities for all pixel dimensions. Relatively high spatial resolution allows accurate MR measurement of constant flow velocity in a small tube at spatial peak velocities for one pixel.

It has been established that estrogen can alter circadian rhythms in behavior and endocrine physiology in rodents. The uterus is a reproductive organ that is critically dependent on regulation by ovarian steroids. Here, we examined the expression of Per1 in different compartments of the uterus, and explored whether the ovarian steroids could regulate Per1 expression employing ovariectomized rat uterus. RT-PCR analysis showed that Per1 was cyclically expressed in the uterus. As revealed by in situ hybridization, the staining intensity of Per1 mRNA was stronger at ZT 8 than at ZT 0 in the uterine luminal epithelium (LE), stroma (S), and myometrium (M) compartments, but was not changed in the glandular epithelium (GE). Both in situ hybridization and immunofluorescence analyses revealed that estradiol (E2) administration induced high expression of Per1 in the LE, GE, and M, and less expression in the S compartment. Progesterone (P4) treatment resulted in an obvious enhancement of Per1 expression in the LE, GE, and S, but unchanged in the M compartment. Furthermore, the E2- and P4-activated Per1 expression was significantly repressed by their respective antagonists, ICI182 780 and RU486. These findings were further supported by RT-PCR analysis of Per1 expression in cultured uterine stromal cells. Collectively, the present data indicate that E2 and P4 might be involved in modification of circadian rhythm via direct regulation of the expression of clock genes.

POSTER PRESENTATION, 12th Annual SCMR Scientific Sessions – 2009 / Orlando, FL, USA / 29 January–1 February 2009

POSTER PRESENTATION, 2011 SCMR/Euro CMR Joint Scientific Sessions / Nice, France / 3-6 February 2011