MR imaging of uterine morphology and dynamic changes during lactation.

PURPOSE: To investigate the influence of lactation and ovarian hormones on uterine morphology and function by comparing uteruses of lactating women with nulliparous women on MRI. MATERIALS AND METHODS: Sagittal T2WI and cine MR images were obtained with 1.5 Tesla (T) and 3T scanner from 22 lactating women and 16 nulliparous women as a control group. The lactating group was further divided into amenorrhea and menorrhea subgroups. Uterine area, endometrial thickness, junctional zone (JZ) thickness, relative signal intensity (rSI) of the JZ, and of the outer myometrium (OM), were measured on T2-weighted fast spin echo images as static image parameters. Frequency of peristalsis (/3min), degree of endometrial transformation, subendometrial conduction, outer myometrial (OM) conduction, and sporadic myometrial contraction were evaluated using cine MR images. The above image parameters were compared between the lactating group and the control group, and between the lactational amenorrhea group and the lactational menorrhea group as a sub-analysis. RESULTS: A significant difference was observed in all the static image parameters and in three of the five cine image parameters between the lactating group and the control group (P < 0.01). In sub-analysis, a statistical significance was found between the lactational amenorrhea group and lactational menorrhea group in area of the uterus and both endometrial and JZ thickness (P < 0.05), but not in cine image parameters (P = 0.682, P = 0.096, P = 0.191, P = 0.939, P = 0.289, respectively). CONCLUSION: Uterine appearance and peristalsis were different between lactating and nulliparous women. The morphological differences were pronounced between lactating amenorrhea and menorrhea women. LEVEL OF EVIDENCE: 2 J. Magn. Reson. Imaging 2017;45:617-623.

Anticholinergic agents result in weaker and shorter suppression of uterine contractility compared with intestinal motion: time course observation with cine MRI.

PURPOSE: To evaluate the time course effects of anticholinergic agents on uterine contractility and intestinal motion with cine magnetic resonance imaging (MRI). MATERIALS AND METHODS: Using a 1.5 T MRI scanner, 60 T2-weighted half-Fourier rapid acquisitions with relaxation enhancement images of the uterus were serially acquired over 3 minutes in 25 healthy women in the periovulatory phase, at four instances, prior to and 2-5, 5-8, and 10-13 minutes after intravenous injection of 20 mg of hyoscine butylbromide. Uterine peristalsis frequency (waves / 3 min) and degrees of endometrial transformation, subendometrial conduction, outer myometrial conduction, sporadic myometrial contraction, and intestinal movement were independently evaluated by three readers. RESULTS: Uterine peristalsis frequency of 6.14 ± 2.34 decreased the most at 2-5 minutes (P < 0.001) by 1.41 (95% confidential interval [CI] = 0.59-2.22), or 23.0% ([6.14-4.73]/6.14) and remained reduced at 5-8 minutes (P = 0.013) by 0.97 (95% CI = 0.15-1.78), or 15.8% ([6.14-5.17]/6.14) after injection. The degree of intestinal movement was 3.32 ± 0.54 and was prominently reduced at every phase (P < 0.001 for all) and maximally decreased to 0.67 ± 0.65 at 5-8 min. It increased to 1.36 ± 0.72 at 10-13 minutes compared with the degrees of motion at 2-5 minutes (P = 0.04) and 5-8 minutes (P = 0.004). CONCLUSION: Suppression of uterine peristalsis was weaker and shorter compared with the stronger and longer suppression of intestinal movement by the intravenous administration of anticholinergic agents.

Optimizing cine MRI for uterine peristalsis: a comparison of three different single shot fast spin echo techniques.

PURPOSE: To determine the optimal single shot fast spin echo (SSFSE) technique by varying interval between image acquisitions for cine MRI of uterine peristalsis. MATERIALS AND METHODS: MRI was performed in 13 premenopausal women (4 normal and 9 with benign pelvic pathology) in various phases of their menstrual cycle. Midsagittal uterus was scanned using a multiphasic SSFSE technique at 2-, 3-, and 4-s intervals over 2 min. Three readers independently and randomly evaluated for peristaltic frequency/2 min, longitudinal direction and intensity of peristalsis in three imaging parameters. Contrast-to-noise ratios (CNRs) were also obtained. RESULTS: Peristaltic frequency for the 2, 3, and 4 s was 2.2 ± 2.3, 3.3 ± 1.5, and 3.6 ± 1.3 waves/2 min, respectively. It increased by 1.5 (95% confidence interval [CI]: 0.31-2.64) waves/2 min with 4 s compared with 2 s. Direction was detected for the 2, 3, and 4 s in 5/13(38%), 9/13(69%) and 12/13(92%) women. Compared with 2 s, intensity of peristalsis in endometrial movement (P = 0.04), signal change of the JZ (P = 0.03), and spread into outer myometrium (P = 0.02), CNRendometrium-JZ by 57% (P < 0.001), and CNRouter myometrium-JZ by 45% (P < 0.01) increased with 4 s. CONCLUSION: Cine MRI with SSFSE sequence for uterine peristaltism is best performed using a 4-s scan interval.

Effect of hyoscine butylbromide (HBB) on the uterine corpus: quantitative assessment with T2-weighted (T2W) MRI in healthy volunteers.

PURPOSE: To investigate effects of hyoscine butylbromide (HBB) on the appearance of three zonal anatomy of the uterine corpus on T2-weighted images (T2WI). MATERIALS AND METHODS: Sagittal T2WI of the pelvis were acquired before and after intramuscular administration of HBB with interval of 10 minutes in 22 healthy volunteers. By drawing polygonal regions of interest (ROIs), the uterine corpus was delineated into outer myometrium (OM), junctional zone (JZ), and endometrium (EM) in 20 subjects. Areas (mm(2)) and relative signal intensity (rSI) of each layer were compared between pre-HBB and post-HBB administration images by using paired t-tests. Histogram analysis was conducted for the uterine layers and changes were visualized. RESULTS: Areas of OM were significantly increased (P = 0.014) and mean rSI of JZ and OM were significantly increased (P = 0.007 and 0.001, respectively) after administration of HBB. Histogram showed an increase in the number of pixels with higher rSI in the OM, which was considered to be caused by an increase in interstitial fluid and vascular dilatation. EM did not show significant changes. CONCLUSION: Layer-wise ROI analyses demonstrated changes in the area and rSI in T2WI of the uterus after HBB administration. Histogram analysis contributed to the investigation of signal changes.

Tazobactam/piperacillin for moderate-to-severe pneumonia in patients with risk for aspiration: comparison with imipenem/cilastatin.

BACKGROUND: Treatment of aspiration pneumonia is becoming an important issue due to aging of populations worldwide. Effectiveness of tazobactam/piperacillin (TAZ/PIPC) in aspiration pneumonia is not clear. PURPOSE: To compare clinical efficacy between TAZ/PIPC (1:4 compound) and imipenem/cilastatin (IPM/CS) in patients with moderate-to-severe aspiration pneumonia. PATIENTS AND METHODS: In this open-label, randomized study either TAZ/PIPC 5 g or IPM/CS 1 g was intravenously administered every 12 h to patients with moderate-to-severe community-acquired aspiration pneumonia or nursing home-acquired pneumonia with risk for aspiration pneumonia for average 11 days. The primary outcome was clinical response rate at the end of treatment (EOT) in validated per-protocol (VPP) population. Secondary outcomes were clinical response during treatment (days 4 and 7) and at the end of study (EOS) in VPP population, and survival at day 30 in modified intention-to-treat (MITT) population. RESULTS: There was no difference between the groups in primary or secondary outcome. However, significantly faster improvement as measured by axillary temperature (p < 0.05) and WBC count (p = 0.01) was observed under TAZ/PIPC treatment. In patients with gram-positive bacterial infection, TAZ/PIPC was more effective at EOT in VPP population (p = 0.03). CONCLUSION: TAZ/PIPC is as effective and safe as IPM/CS in the treatment of moderate- to-severe aspiration pneumonia.

Nonovarian cystic lesions of the pelvis.

Cystic disease in the female pelvis is common. The majority of cystic pelvic masses originate in the ovary, and they can range from simple, functional cysts to malignant ovarian tumors. Mimics of ovarian cystic masses include peritoneal inclusion cyst, paraovarian cyst, mucocele of the appendix, obstructed fallopian tube (eg, hydrosalpinx, pyosalpinx, and hematosalpinx), uterine leiomyoma, adenomyosis, spinal meningeal cyst, unicornuate uterus, lymphocele, cystic degeneration of lymph nodes, lymphangioleiomyomatosis, hematoma, and abscess. A cystic pelvic mass is nonovarian if it is separate from the normal ovaries. However, the different types of cystic pelvic masses may have similar imaging appearances, and radiologic evaluation may be of limited diagnostic use. It is important to understand the relationship of a mass with its anatomic location, identify normal ovaries at imaging, and relate imaging findings to the patient's clinical history to avoid misdiagnosis.

Do anticholinergic agents suppress uterine peristalsis and sporadic myometrial contractions at cine MR imaging?

PURPOSE: To prospectively evaluate anticholinergic drug effects on uterine peristalsis and sporadic myometrial contractions, as well as on intestinal motion, with cine magnetic resonance (MR) imaging. MATERIALS AND METHODS: This prospective study was approved by the institutional review board; informed consent was obtained from all participants. Twenty-one women (mean age, 29.3 years +/- 4.0 [standard deviation]) underwent MR imaging during the follicular through periovulatory phases (cycle days 5-26). Before and after injection of an anticholinergic agent, 60 serial half-Fourier rapid acquisition with relaxation enhancement MR images were obtained within 2 minutes in the midsagittal uterine plane. Evaluations were performed independently and separately in random order by two radiologists who were blinded to whether an anticholingeric agent had been administered. Uterine peristalsis was evaluated for frequency (paired t test), predominant direction (McNemar test), degree of endometrial movement, wave conduction in the junctional zone (JZ), and wave conduction toward the outer myometrium (Wilcoxon signed rank test). Degree of sporadic contractions in the outer myometrium and intestinal motion were also evaluated (Wilcoxon signed rank test). RESULTS: On postinjection images, uterine peristalsis decreased in frequency from 4.57 waves per 2 minutes +/- 1.62 to 3.52 waves per 2 minutes +/- 1.59, which is a 23% (95% confidence interval: 8.7%, 37.2%) average reduction (P = .003). There was no significant difference in actual predominant uterine peristalsis direction between pre- and postinjection images (P > .99). Although there were trends toward reduction of the degree of endometrial movement and of wave conduction in the JZ and toward the outer myometrium, these were not significant. The degree of sporadic myometrial contractions (P = .001) and intestinal motion (P < .001) decreased on postinjection images. CONCLUSION: Anticholinergic agents significantly suppress sporadic myometrial contractions and uterine peristalsis, in addition to intestinal motion, all of which may contribute to improved quality of conventional uterine MR images.

Intrauterine devices and uterine peristalsis: evaluation with MRI.

Intrauterine devices (IUDs) have been viewed as an effective form of contraception. However, the mechanism by which IUDs disturb fertility remains controversial. This study aimed to evaluate the effects of IUDs on uterine contractility using cine MR. Eleven healthy female volunteers of reproductive age bearing IUDs and 12 women not bearing IUDs were evaluated during the periovulatory phase. MR images were obtained with a 1.5-T magnet, acquiring 60 serial images every 3 s via half-Fourier acquisition single-shot turbo spin echo to be displayed on cine mode. Assessments were based on (a) the presence of peristaltic waves, (b) the frequency and direction of peristaltic waves and (c) the extent of peristaltic waves. Static images were evaluated for thickness of the junctional zone (JZ) and myometrium. A fundo-cervical (FC)-directed peristaltic wave was identified in 4 of 11 IUD-bearing subjects and in only 1 of 12 subjects from the control group. FC waves extended through more than half of the thickness of the myometrium. Peristaltic frequency in IUD users (5.0/3 min) was less than that of the control group (6.5/3 min). The JZ and myometrium were significantly thicker in IUD users. FC-directed waves were more often observed in IUD-bearing subjects, which might explain the inhibition of active sperm transport.

Functional MR imaging of the uterus.

Recent developments in MR imaging techniques have enabled the functional assessment of the uterus. Cine MR imaging is a useful tool for evaluating uterine kinematic functions derived from myometrial contractility, and for investigating the alteration of uterine contractility in a variety of conditions and gynecologic disorders. Diffusion-weighted imaging can demonstrate abnormal signal in pathologic foci based on differences in molecular diffusion, and could provide useful information in evaluating malignant conditions. Dynamic contrast-enhanced MR imaging has the potential to improve tumor detection and local staging, and quantitative information may be useful for both monitoring therapeutic effects and predicting outcome. These state-of-the-art functional MR imaging techniques are beneficial for elucidating various uterine conditions when used appropriately, and the findings further provide the basis of future MR imaging investigations.

Investigation of uterine peristalsis diurnal variation.

BACKGROUND: In women of reproductive age, wavelike movements of the subendometrial myometrium, which is called uterine peristalsis, is considered to be related with fertility and menstrual problems. This is because the direction and frequency of peristalsis is known to be different among menstrual cycle phases. However, nothing is known as regarding diurnal variations. This study was designed to evaluate for the presence of a diurnal variation in uterine peristalsis. MATERIALS AND METHODS: MR studies were performed on 12 volunteers of reproductive age using a 1.5-T magnet, four times per day (at 0800, 1300, 1800 and 2300 h) during three (periovulatory, luteal and menstrual) phases of one menstrual cycle. Sixty images were obtained by half-Fourier acquisition single-shot turbo spin echo every 2 s and displayed on cine mode. Semiautomated software was utilized to discern the presence of peristaltic waves, as well as peristaltic frequency and direction. The presence of sustained contractions was visually determined. RESULTS: There was no statistically significant difference during the daytime for frequency and direction of uterine peristalsis for all menstrual cycle phases. Nonetheless, peristaltic frequency and direction fluctuated during each cycle. Statistically significant peristaltic suppression was observed in association with sustained contractions during the periovulatory phase. CONCLUSIONS: A diurnal variation was not observed for uterine peristalsis. Sporadic changes in peristaltic frequency were observed and appear to be closely related to sustained uterine contractions.

Uterine contractions evaluated on cine MR imaging in patients with uterine leiomyomas.

PURPOSE: Submucosal leiomyoma is one of the most recognized causes of infertility and habitual abortion. The purpose of this study is to evaluate uterine peristalsis, a cycle-related inherent contractility of uterus probably responsible for sperm transport and conservation of pregnancy, in patients with uterine leiomyomas using cine magnetic resonance (MR) imaging. MATERIALS AND METHODS: Study population consisted of 26 female patients (age range: 19-51 years, mean: 41 years), in which 16 patients had submucosal leiomyomas and 10 patients had intramural or subserosal leiomyomas. We prospectively performed MR imaging of the midsagittal plane of uterus using 1.5 T magnet (Symphony, Siemens Medical Systems) with a body array coil, and obtained 60 half-Fourier acquisition single shot turbo spin echo (HASTE) images (Echo time=80 ms, FOV=300 mm, slice thickness 5 mm, matrix 256x256) within 2 min, and displayed them on cine mode at 12x faster than real speed. Evaluated were peristaltic movements at the endometral-myometrial junction and focal myometrial movements, adjacent to leiomyomas, regarding presence, direction, frequency, and conduction. RESULTS: The peristaltic movements were identified in 12/16 patients with submucosal lesions and 10/10 with other leiomyomas. The frequency and direction were cycle-related. Loss of peristalsis was noted adjacent to submucosal myomas in 4/12 patients, but was not in others. Focal myometrial movements were noted in 9/16 patients with submucosal myomas, but not in others. CONCLUSIONS: Uterine peristaltic movements were partly interrupted by submucosal leiomoymas, but not by myometrial or subserosal leiomyomas. Loss of peristalsis and focal myometrial movements was noted only adjacent to submucosal leiomyomas. These findings are considered to represent dysfunctional contractility, and may be related with pregnancy loss.

Kinematics of the uterus: cine mode MR imaging.

Cine mode magnetic resonance (MR) imaging has allowed evaluation of kinematics of the pelvis. Visualization of dynamic changes under strain facilitates evaluation of prolapses and adhesions between organs. The uterus, an organ of smooth muscle, has an inherent contractility that characterizes it as different from other visceral organs. This sustained contraction has occasionally been shown on static images as a finding masquerading as a leiomyoma or as adenomyosis. Cine mode MR imaging clearly shows the configuration of the myometrium during these dynamic changes, as well as its signal intensity during contractions. Uterine peristalsis, the subtle and rhythmic contractions of the inner myometrium, is also clearly identifiable on cine mode images as a wavy movement of the endometrium and/or inner myometrium. The direction and frequency of uterine peristalsis are different in each of the menstrual cycle phases and are thought to have important roles in uterine function, such as in fertility and menstrual blood discharge. Elucidation of these kinematics of the uterus will help in the evaluation of static MR images and study of the physiology of the uterus. Cine MR imaging is a novel technique for diagnosis and evaluation of the pelvic organs, especially the uterus.

The effect of oral contraceptives on uterine contractility and menstrual pain: an assessment with cine MR imaging.

BACKGROUND: Low-dose oral contraceptives (OC) have been reported to control primary dysmenorrhea. Furthermore, a close relationship between dysmenorrhea and uterine contractions has been visualized with magnetic resonance imaging (MRI). This study aimed to use cine MR to demonstrate the effects of OC on myometrial contractility during menstruation and to associate the findings with dysmenorrhea. METHODS: MR studies were obtained of 21 healthy female volunteers (22-47 years old) taking OC, and 20 control women (24-39 years old) not taking OC. Cine- and static MR images were obtained with a 1.5 T magnet during menstruation. Uterine contractility was assessed by the presence of endometrial distortion on cine MR, the area of the mid-sagittal uterine myometrium, and the thickness of the subendometrial low-intensity area on static images. Dysmenorrhea were assessed via a questionnaire. RESULTS: A total of 21 OC users and 20 controls were included in the analysis. Endometrial distortion was significantly less prominent and the subendometrial low-intensity area was significantly thinner in the OC group. Furthermore in the OC group, the uterine myometrial area was larger (although not significantly) and the degree of assessed pain was significantly lower. CONCLUSIONS: Both cine- and static MR images demonstrate that myometrial contractility was relatively suppressed in OC users, which may represent one of the reasons explaining the reduced menstrual pain experienced by OC users.

Artifacts and pitfalls in MR imaging of the pelvis.

Artifacts are intimately intertwined with MRI. For the practicing radiologist, effective supervision, troubleshooting, and interpretation of diagnostic MR studies require a solid knowledge of the pertinent artifacts. This article seeks to familiarize the reader with commonly encountered artifacts and pitfalls in pelvic imaging, the mechanism behind their generation, and methods of minimizing their negative impact or maximizing their diagnostic yield. It also serves as an exciting tool to learn many aspects of basic and advanced MR physics. Artifacts are categorized into patient- and sequence-related artifacts. Various manifestations of motion and vascular artifacts, susceptibility, altered tissue contrast, blurring, chemical shift artifact, volume averaging, and gadolinium (Gd) pseudolayering are explained, along with their proposed remedies.

Dysmenorrhea: evaluation with cine-mode-display MR imaging--initial experience.

PURPOSE: To prospectively evaluate uterine contractility during menstruation and its relation to primary dysmenorrhea by using magnetic resonance (MR) imaging with cine mode display. MATERIALS AND METHODS: The university ethics committee approved the study protocol, and all subjects gave written informed consent. Nineteen healthy women were examined during menstrual cycle days 1-3 by using a 1.5-T-magnet unit. Sixty serial half-Fourier rapid acquisition with relaxation enhancement MR images of the uterus were obtained every 3 seconds for 3 minutes and displayed in cine mode. MR images were analyzed in terms of thickness of the inner low-signal-intensity myometrial layer, presence of endometrial distortion, and uterine peristalsis detectability. Pain was assessed by using a four-point scale. For 56 MR imaging cases, the association between MR imaging findings and pain degree was examined with Spearman correlation and Mann-Whitney tests. MR imaging findings in the dysmenorrheic and eumenorrheic subject groups were compared by using Mann-Whitney and chi(2) tests. The area of the uterine myometrium in both groups was calculated for quantitative assessment of uterine contraction and was compared between the groups by using the Student t test. RESULTS: MR imaging findings revealed marked changes during cycle days 1-3. Thickness of the inner low-signal-intensity myometrial layer and endometrial distortion were significantly associated with pain degree (P < .001), while uterine peristalsis was undetectable when pain was severe or moderate. The area of the uterine myometrium significantly decreased during cycle days 1-3 in the dysmenorrheic group, as compared with that in the eumenorrheic group (P = .010). CONCLUSION: MR imaging features of the uterus on cycle days 1-3 correlated with pain degree. Cine-mode-display MR imaging is a potential tool for evaluating dysmenorrhea.

Oral contraceptives and uterine peristalsis: evaluation with MRI.

PURPOSE: To evaluate the effects of oral contraceptives (OCs) on uterine contractility using cine MRI, and correlate the kinematic findings with the static findings. MATERIALS AND METHODS: Healthy female volunteers of reproductive age (23 taking OCs, and 15 not) were evaluated at mid-cycle. MR images were obtained with a 1.5T magnet, with 60 serial images taken every three seconds by half-Fourier acquisition single-shot turbo spin echo (HASTE) to be displayed in cine mode. Assessments were based on the 1) detectability of uterine peristalsis in cine mode, 2) peristaltic frequency and direction, 3) thickness of the endometrium, myometrium, and junctional zone (JZ) on T2-weighted images (T2WIs), and 4) intensity of the myometrium and cervical mucus on T2WIs and T1-weighted images (T1WIs), respectively. RESULTS: Uterine peristalsis was markedly decreased in the OC users. The endometrium and JZ were significantly thinner, and the myometrium was thicker in the OC users compared to controls. The signal intensity of the myometrium and cervical mucus was significantly higher in the OC users than in controls. CONCLUSION: OCs markedly suppressed uterine peristalsis at mid-cycle, and the uterus displayed a globular configuration with a thin JZ that may be related to decreased uterine peristalsis in OC users.

A semiautomated technique for evaluation of uterine peristalsis.

PURPOSE: To evaluate the capability of a newly developed semiautomatic analysis technique for evaluation of uterine peristalsis in comparison with visual assessment. MATERIALS AND METHODS: Cine magnetic resonance (MR) images were obtained from 16 normal volunteers in periovulatory phase. Sixty-eight studies were evaluated by both visual evaluation and by a semiautomated computer assisted software. The software was developed by applying an automated contour tracking method and enables objective analysis of frequency, amplitude, velocity, and direction. Assessments were based on: 1) the recognition of peristalsis, 2) peristaltic direction and frequency, and 3) the way of recognizing peristaltic direction. The data obtained by both modalities were compared with those of previously reported ultrasound (US) findings. RESULTS: Uterine peristalsis was identified in all studies by both objective and visual analyses. There was no significant difference in the identification of peristalsis, recognition of peristaltic directions, or peristaltic frequency (P > 0.05). Data were well in accordance with those in US literature. Peristaltic direction was recognized either by configuration change in the endometrium or by conduction of low signal intensity in the subendometrial myometrium and there was statistically no difference. CONCLUSION: Evaluation of uterine peristalsis by the semiautomatic analysis accorded well with the results obtained visual assessments and previous US findings.

Uterine peristalsis: comparison of transvaginal ultrasound and two different sequences of cine MR imaging.

PURPOSE: To compare uterine peristalsis as seen on two different magnetic resonance (MR) imaging sequences and transvaginal ultrasound (TVUS), so as to better determine the best method for evaluating uterine peristalsis. MATERIALS AND METHODS: Eleven women in the periovulatory phase of the menstrual cycle underwent TVUS and cine MR imaging within a time period of three hours. Findings on cine MR images obtained with a serial 60 half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence and a 300 true fast imaging with steady-state precession (FISP) sequence were compared with TVUS. RESULTS: The image quality of the HASTE technique was the best among the three methods, followed by TVUS, and then true FISP technique (P < 0.001). Uterine peristalsis was detected in 100% of subjects using HASTE, 82% with True FISP, and 100% with TVUS. With HASTE technique, true FISP, and TVUS, respectively, endometrial stripping movement was identified in 100%, 82%, and 100%; direction was identified in 100%, 45% (P = 0.014), and 73%; and wave conduction toward the outer myometrium was identified in 55%, 9% (P = 0.025), and 0% (P = 0.014). CONCLUSION: Cine MR imaging by HASTE technique with a time resolution of two seconds best delineated uterine peristalsis compared to that by true FISP technique or with TVUS.

Uterine peristalsis shown on cine MR imaging using ultrafast sequence.

PURPOSE: To demonstrate and evaluate uterine peristalsis on cine magnetic resonance imaging (MRI) using ultrafast imaging. MATERIALS AND METHODS: Serial MR uterine images (300) were obtained from 15 normal volunteers over four menstrual phases using true fast imaging with steady-state precession (true FISP) technique over 117 seconds and videotaped. Three radiologists independently evaluated videotapes of 59 studies. Uterine peristalsis was defined as wavy movements of subendometrial myometrium or endometrium. Interobserver reliability was evaluated using a Kappa coefficient. Fifty-four studies obtained in appropriate phases were analyzed. RESULTS: Cine MRI displayed uterine peristalsis in 30 of 59 studies; consensus reading showed direction in 23 studies. Reliability between the final consensus of the recognition of uterine peristalsis and those of the three readers was extremely concordant, with a Kappa coefficient of 0.908. Wave direction was cervico-fundal in follicular and periovulatory phases, with frequency of contraction waves being 1.2-2.3 per minute in positive studies. CONCLUSION: Uterine peristalsis was demonstrated on cine MR using ultrafast MRI. Direction and frequency of peristaltic waves are closely related to menstrual cycle phases. Supplementary material for this article can be found on the JMRI website at http://www.interscience.wiley.com/jpages/1053-1807/suppmat/index.html.