Assessment of magnetic field interactions and heating for cerebral aneurysm flow diverters during 7T MRI.

Flow diverters (FDs) are utilized for a wide range of aneurysms, but show safety issues such as adverse interactions with static magnetic fields (displacement force and torque) and radiofrequency-induced heating during magnetic resonance imaging (MRI). The present study aimed to assess these adverse interactions in a 7-tesla (7T) static magnetic field and radiofrequency-induced heating during a 7T MRI for two types of FD. Displacement force and magnetically induced torque were assessed using the deflection angle method and low friction surface method, respectively. To assess heating, each FD was set in a phantom filled with gelled-saline mixed with polyacrylic acid and underwent a 7T MRI using a three-dimensional fast spin echo method. Displacement force and magnetically induced torque in the 7T static magnetic field were undetectable, and radiofrequency-induced heating during 7T MRI remained ≤ 0.6 °C for both types of FD, suggesting that magnetic field interactions and heating on FDs during a 7T MRI are acceptable from a safety perspective.

Effect of the addition of 123I-iomazenil single-photon emission computed tomography to brain perfusion single-photon emission computed tomography on the detection accuracy of misery perfusion in adult patients with ischemic moyamoya disease.

OBJECTIVE: The present prospective study aimed to determine whether the addition of 123I-iomazenil (IMZ) single-photon emission computed tomography (SPECT) to brain perfusion SPECT could improve the detection accuracy of misery perfusion on positron emission tomography (PET) in adult patients with ischemic moyamoya disease (MMD). METHODS: Oxygen extraction fraction (OEF) and brain perfusion were assessed using 15O gas PET and N-isopropyl-p-[123I]-iodoamphetamine (IMP) SPECT, respectively, in 137 patients. IMZ SPECT was also performed. Regions of interest (ROIs) were automatically placed in the five middle cerebral artery (MCA) territories ipsilateral to the symptomatic cerebral hemisphere and in the contralateral posterior cerebral artery territory using a three-dimensional stereotaxic ROI template. The radioactive count of the MCA ROI to the contralateral posterior cerebral artery ROI was calculated on IMP SPECT (relative SPECT-IMP uptake) and IMZ SPECT (relative SPECT-IMZ uptake). The relative SPECT-IMZ uptake to the relative SPECT-IMP uptake was also calculated (relative SPECT-IMZ/IMP uptake). Of the five MCA ROIs in the symptomatic cerebral hemisphere in each patient, the ROI with the highest PET-OEF value (one ROI per patient) was selected for analysis. RESULTS: Significant correlations were observed between the PET-OEF and relative SPECT-IMP uptake (correlation coefficient, - 0.683) and relative SPECT-IMZ/IMP uptake (correlation coefficient, 0.875). The area under the receiver operating characteristic curve for detecting misery perfusion (PET-OEF > 51.3%) was significantly greater for the relative SPECT-IMZ/IMP uptake than for the relative SPECT-IMP uptake (difference between areas, 0.080; p = 0.0004). The sensitivity, specificity, and positive- and negative-predictive values for the relative SPECT-IMZ/IMP uptake for detecting misery perfusion were 100%, 92%, 81%, and 100%, respectively. The specificity and positive-predictive value were significantly greater for the relative SPECT-IMZ/IMP uptake than for the relative SPECT-IMP uptake. CONCLUSIONS: The addition of IMZ SPECT to brain perfusion SPECT improves the detection accuracy of misery perfusion on PET in adult patients with ischemic MMD.

Rupture of Vertebral Artery Dissecting Aneurysm after mRNA Anti-COVID-19 Vaccination: A Report of Two Cases.

The coronavirus disease 2019 (COVID-19) pandemic continues to spread around the world, and widespread vaccination is considered the most effective way to end it. Although the efficacy of COVID-19 vaccines has been confirmed, their safety remains a concern. In this paper, we report two cases of ruptured vertebral artery dissecting aneurysm (VADA) immediately after messenger RNA (mRNA) anti-COVID-19 vaccination. In Case 1, a 60-year-old woman experienced sudden headache 3 weeks before her first dose of the Moderna mRNA-1273 COVID-19 vaccine. Magnetic resonance imaging showed dilatation of the right vertebral artery (VA) without intracranial hemorrhage. A day after the vaccination, she developed subarachnoid hemorrhage with pulmonary effusion due to a ruptured right VADA. She underwent endovascular internal trapping and parent artery occlusion under general anesthesia. In Case 2, a 72-year-old woman with a previous history of the left VA occlusion due to arterial dissection developed subarachnoid hemorrhage 7 days after the first dose of the Pfizer-BioNTech BNT162b2 COVID-19 mRNA vaccine due to a ruptured right VADA and underwent stent-assisted coil embolization under general anesthesia. The postoperative courses of these two cases were uneventful. The accumulation of more cases and further study are warranted to clarify the relationship between COVID-19 mRNA vaccination and ruptured intracranial dissecting aneurysms.

Five-Year Outcomes of Medical Management Alone for Adult Patients with Ischemic Moyamoya Disease without Cerebral Misery Perfusion.

INTRODUCTION: No clear guidelines for treating adult patients with ischemic moyamoya disease (MMD) without cerebral hemodynamic compromise such as misery perfusion have been established. Our previous prospective cohort study of adult patients with MMD without misery perfusion who were treated with medical management alone, including an antiplatelet drug, showed a recurrent ischemic event rate of 3% per 2 years. The present prospective study aimed to elucidate the 5-year clinical, cerebral perfusion, and cognitive outcomes of medical management alone for Japanese adult patients with ischemic MMD without cerebral misery perfusion by following the same patients for another 3 years. METHODS: In total, 68 patients without recurrent events at a 2-year follow-up were prospectively followed up for another 3 years. Cerebral blood flow (CBF) in the symptomatic cerebral hemisphere was measured using brain perfusion single-photon emission computed tomography at inclusion and at the end of the subsequent 3-year follow-up. Neuropsychological testing was performed at inclusion and at the end of the initial 2- and subsequent 3-year follow-ups. RESULTS: During the subsequent 3-year follow-up, 2 patients (3%) developed further ischemic events. In patients without further ischemic events, CBF was significantly greater at the end of the subsequent 3-year follow-up than at inclusion (p = 0.0037), and all neuropsychological test scores improved or remained unchanged at the end of initial 2- and subsequent 3-year follow-ups compared with that at inclusion. CONCLUSION: In adult patients receiving medical management alone for ischemic MMD without cerebral misery perfusion, the incidence of further ischemic events was 6% per 5 years and did not change between the initial 2 years after the last is-chemic event and the subsequent 3 years. In patients without further ischemic events, CBF and cognitive function had not deteriorated at 5 years after the last ischemic event.

Development of cerebral microbleeds in patients with cerebral hyperperfusion following carotid endarterectomy and its relation to postoperative cognitive decline.

OBJECTIVE: A primary cause of cognitive decline after carotid endarterectomy (CEA) is cerebral injury due to cerebral hyperperfusion. However, the mechanisms of how cerebral hyperperfusion induces cerebral cortex and white matter injury are not known. The presence of cerebral microbleeds (CMBs) on susceptibility-weighted imaging (SWI) is independently associated with a decline in global cognitive function. The purpose of this prospective observational study was to determine whether cerebral hyperperfusion following CEA leads to the development of CMBs and if postoperative cognitive decline is related to these developed CMBs. METHODS: During the 27-month study period, patients who underwent CEA for ipsilateral internal carotid artery stenosis (≥ 70%) also underwent SWI and neuropsychological testing before and 2 months after surgery, as well as quantitative brain perfusion SPECT prior to and immediately after surgery. RESULTS: According to quantitative brain perfusion SPECT and SWI before and after surgery, 12 (16%) and 7 (9%) of 75 patients exhibited postoperative cerebral hyperperfusion and increased CMBs in the cerebral hemisphere ipsilateral to surgery, respectively. Cerebral hyperperfusion was associated with an increase in CMBs after surgery (logistic regression analysis, 95% CI 5.08-31.25, p < 0.0001). According to neuropsychological assessments before and after surgery, 10 patients (13%) showed postoperative cognitive decline. Increased CMBs were associated with cognitive decline after surgery (logistic regression analysis, 95% CI 6.80-66.67, p < 0.0001). Among the patients with cerebral hyperperfusion after surgery, the incidence of postoperative cognitive decline was higher in those with increased CMBs (100%) than in those without (20%; p = 0.0101). CONCLUSIONS: Cerebral hyperperfusion following CEA leads to the development of CMBs, and postoperative cognitive decline is related to these developed CMBs.

Optimal timing for measuring cerebral blood flow after acetazolamide administration to detect preexisting cerebral hemodynamics and metabolism in patients with bilateral major cerebral artery steno-occlusive diseases: 15O positron emission tomography studies.

The present study determined the optimal timing of scanning for measurement of cerebral blood flow (CBF) after acetazolamide (ACZ) administration for detection of preexisting cerebral hemodynamics and metabolism in bilateral major cerebral artery steno-occlusive diseases. Thirty three patients underwent 15O gas positron emission tomography (PET) and each parameter was obtained in the bilateral middle cerebral artery (MCA) territories. CBF was also obtained using H2 15O PET scanning performed at baseline and at 5, 15, and 30 min after ACZ administration. Relative CBF at each time point after ACZ administration to baseline CBF was calculated. For MCA territories with normal cerebral blood volume (CBV) and cerebral metabolic rate of oxygen (CMRO2), CBF continued increasing until 15 min after ACZ administration. For MCA territories with abnormally increased CBV, CBF decreased 5 min after ACZ administration. After that, CBF continued increasing until 30 min after ACZ administration. For MCA territories with abnormally decreased CMRO2, CBF did not change 5 min after ACZ administration. Ten min later, CBF increased. The accuracy to detect abnormally increased CBV was significantly greater for relative CBF5 than for relative CBF15. The accuracy to detect abnormally decreased CMRO2 was significantly greater for relative CBF5 or CBF15 than for relative CBF30. For detecting abnormally increased oxygen extraction fraction, the accuracy did not differ among each relative CBF. These findings suggested that CBF measurement at 5 min after ACZ administration is the optimal timing for detection of preexisting cerebral hemodynamics and metabolism in bilateral major cerebral artery steno-occlusive diseases.

Comparison of Subjective and Objective Assessments on Improvement in Gait Function after Carotid Endarterectomy.

The purpose of the present study was to determine whether objective gait test scores obtained using a tri-axial accelerometer can detect subjective improvement in gait as determined by the patient after carotid endarterectomy (CEA). Each patient undergoing CEA for ipsilateral internal carotid artery stenosis determined whether their gait was subjectively improved at six months after CEA when compared with preoperatively. Gait testing using a tri-axial accelerometer was also performed preoperatively and six months postoperatively. Twelve (15%) of 79 patients reported subjectively improved gait. Areas under the receiver operating characteristic curve for differences between pre- and postoperative test values in stride time, cadence, and ground floor reaction for detecting subjectively improved gait were 0.995 (95% confidence interval (CI), 0.945-1.000), 0.958 (95%CI, 0.887-0.990), and 0.851 (95%CI, 0.753-0.921), respectively. Cut-off points for value differences in detecting subjectively improved gait were identical to mean -1.7 standard deviation (SD) for stride time, mean +1.6 SD for cadence, and mean +0.4 SD for ground floor reaction of control values from normal subjects. Objective gait test scores obtained using the tri-axial accelerometer can detect subjective gait improvements after CEA. When determining significant postoperative improvements in gait using a tri-axial accelerometer, optimal cut-off points for each test value can be defined.

Oocyte retrieval after heterotopic transplantation of ovarian tissue cryopreserved by closed vitrification protocol.

PURPOSE: A device for closed vitrification was designed to reduce the risk of contamination and investigated on its efficacy for ovarian function recovery after cryopreservation and heterotopic transplantation. METHODS: Ovarian tissues from green fluorescence protein transgenic mice (10 GFP mice) were vitrified using the device, and warmed ovarian tissues were transplanted into the ovarian bursa region in wild-type female mice (6 mice). Fresh ovarian tissues were similarly transplanted as a control. After recovery of the estrous cycle, mice were mated with male mice. Ovarian tissues from six cynomolgus monkeys were vitrified and warmed with the device for autologous, heterotopic transplantation. Fresh tissue transplantation was not performed for the control. Ovarian function was examined by recovery of the hormonal cycle. Histological examination was conducted. RESULTS: The number of live pups per recipient mouse was not significantly different after transplantation of fresh or vitrified-warmed ovarian tissue, although the pregnancy rate was reduced with vitrified tissues. The hormonal cycle was restored in 5/6 monkeys after heterotopic transplantation of vitrified-warmed ovarian tissue. Follicles were harvested at eight sites in the omentum and 13 sites in the mesosalpinx. In vitro maturation (IVM)/IVF produced embryo but did not develop. CONCLUSIONS: Resumption of the hormonal cycles, follicle development, and oocyte retrieval from vitrified-warmed ovarian tissue transplants may indicate that the use of vitrification for ovarian tissue in a closed system has a potential of clinical application without the risk of contaminations. More detailed analyses of the effects of vitrification on ovarian tissue, such as gene expression patterns in oocytes and granulosa cells, may be needed for establishing a standard procedure for cryopreservation of ovarian tissues in human.

Menopause-specific health literacy in Japanese women.

OBJECTIVES: This study proposed a method for assessing menopause-specific health literacy (knowledge and beliefs about menopausal symptoms which aid their recognition, assessment, and management) using a vignette methodology. STUDY DESIGN: A cross-sectional web-based survey was conducted in September 2015 among Japanese women aged 30-59 years. Of 1236 women surveyed, 1196 eligible participants who were not under treatment for menopausal symptoms were included. MAIN OUTCOME MEASURES: Participants were presented with a vignette describing a woman with menopausal symptoms and were then asked a series of questions to assess their recognition of menopausal symptoms, attitude, subjective norm, perceived behavior control, availability, and intention to seek medical care if they themselves had the problems described in the vignette. RESULTS: The majority (87%) of participants correctly labelled the vignette as menopausal symptoms and 60% expressed an intention to seek medical care if they had the symptoms presented. Logistic regression showed that attitude, subjective norm, and perceived behavior control were significant predictors of the intention to seek medical care. A structural equation model depicting these relationships with intention to seek medical care revealed acceptable fit indices: goodness of fit index (GFI)=0.948, adjusted goodness of fit index (AGFI)=0.913, comparative fit index (CFI)=0.883, and root mean square error of approximation (RMSEA)=0.089. Subjective norm had the greatest direct effect on intention to seek medical care. CONCLUSIONS: The assessment of menopause-specific health literacy may be useful for understanding why women hesitate to seek medical care for menopausal symptoms and for developing interventions to improve the coping behaviors of women with menopausal symptoms.

Prenatal diagnosis of pyriform sinus fistula: case report and literature review.

We describe a case of prenatal diagnosis of a pharyngeal cyst as a pyriform sinus fistula on the findings of ultrasonography and magnetic resonance imaging.

Peripartum heart failure caused by left ventricular diastolic dysfunction: a case report.

Peripartum cardiomyopathy is a rare but potentially life-threatening condition. The current definition of peripartum cardiomyopathy only includes patients with systolic dysfunction. We describe a 25-year-old nulligravid patient with heart failure, i.e. left ventricular diastolic dysfunction with preserved systolic dysfunction during the third trimester of pregnancy. She complained of dyspnea and was referred to our hospital at 31 weeks of gestation. The patient met the clinical criteria for peripartum cardiomyopathy with the exception of systolic dysfunction. Brain-type natriuretic peptide levels peaked at 1447 pg/dL. The patient responded to therapy for heart failure and showed resolution of her diastolic dysfunction by 1 month postpartum. The case demonstrated the important role of diastolic dysfunction in peripartum heart failure and the possibility of clarifying the pathophysiology of peripartum cardiomyopathy by evaluating diastolic function. Further investigations are needed to provide evidence regarding the clinical role of diastolic dysfunction in peripartum heart failure.

N-butyl cyanoacrylate is very effective for massive haemorrhage during the perinatal period.

OBJECTIVE: The liquid embolic agent n-butyl cyanoacrylate (NBCA) is a tissue adhesive used as an immediate and permanent embolic agent when mixed with oil-based contrast medium. In this study, the preservation of fertility with TAE using NBCA for massive haemorrhage during pregnancy or the peripartum period and the utility of this therapy were investigated. METHODS: Cases from January 2005 to October 2010 in which TAE was performed for massive haemorrhage in pregnant women, particularly during the peripartum period, were investigated. RESULTS: TAE was performed in 27 pregnant women. The embolic agent used was GS only in five cases, NBCA only in 19 cases, and additional embolization with NBCA when the effect with GS was insufficient in three cases, one each of abruptio placentae, cervical pregnancy, and uterine atony.A comparison of mean blood loss when each embolic agent was used for haemostasis showed a significant difference between cases in which GS only was used and cases in which NBCA only was used. In a comparison of mean transfusion volume, a significant difference was seen between cases in which both GS and NBCA were used and cases in which NBCA only was used. In a postoperative follow-up survey, menses resumed in eight patients, including four patients who later became pregnant and three who delivered. CONCLUSIONS: TAE with NBCA, which has an embolic effect unrelated to clotting dysfunction for massive haemorrhage during the peripartum period, is a minimally invasive and very effective treatment method for patients with severe DIC.

Assessment of long-term function of heterotopic transplants of vitrified ovarian tissue in cynomolgus monkeys.

BACKGROUND: Ovarian tissue cryopreservation by rapid cooling (vitrification) is a convenient fertility preservation option. However, the progress of vitrified ovarian tissue after transplantation is not well understood in primates. METHODS: For tissues from cynomolgus monkeys, we used closed straw vitrification and open cryosupport vitrification in which tissues are immersed directly into liquid nitrogen. Following warming, ovarian cortical pieces were autotransplanted and their function was monitored by computed tomography (CT), hormone assays and oocyte recovery, ICSI and embryo transfers (ETs). RESULTS: Hormone cycles were restored in 6 of 7 animals in a mean of 126 days with no significant difference between the two vitrification regimens. The presence of new blood vessels supplying the grafted ovarian tissue was confirmed by contrast-enhanced CT. Oocyte retrieval from two monkeys after transplantation of the ovarian cortex vitrified by cryosupport vitrification yielded a total of nine oocytes of which six fertilized after ICSI, but ETs did not lead to any pregnancies. CONCLUSIONS: This work shows that CT can give insight into ovarian function after heterotopic transplantation, and that heterotopic autografts of vitrified ovarian cortex can give rise to long-term ovarian function and embryos in a primate model. It remains to be established how outcomes following rapid vitrification compared with outcomes following conventional slow cooling procedures.

[The possibility of the fertility preservation in young cancer patients based on practice of oncofertility treatment].

Young female cancer patients face various problems, including a decrease in their quality of life(QOL)due to early menopause or loss of fertility after remission. Chemotherapy and radiotherapy can cause loss of reproductive function in young women due to adverse effects such as ovarian failure. The frequency of ovarian failure depends on the age of the patient, the anticancer agents used, and the dose of each agent. In these patients, improvement of the post-treatment QOL and fertility preservation can be achieved by measures such as protection of ovarian function against the effects of anticancer agents. Ovum freezing or fertilized egg freezing are also becoming fertility preservation methods for these patients. However, ovarian hyperstimulation to obtain ova is time consuming and sometimes considered taboo depending on the type of cancer. A self solution to problems occurring frequently at the same time is demanded from the patient, and the patient is forced to deal with too many choices in too little time. It is often less than one month until the cancer treatment begins after an underlying disease is diagnosed, since chemotherapy cannot be delayed. In these cases, cryopreservation of ovarian tissue is currently proposed for fertility preservation. In this manuscript, I will discuss a topic about fertility preservation in young cancer survivors including recent knowledge regarding cryopreservation of ovarian tissue.

A case of pregnancy and childbirth after uterine artery embolization with a permanent embolic agent.

OBJECTIVE: To report a case of full-term delivery after uterine artery embolization with N-butyl cyanoacrylate for abruptio placentae. DESIGN: Case report. SETTING: University hospital. PATIENT(S): A 35-year old woman, gravida 2 para 0, at 32 weeks' and 4 days' gestation. INTERVENTION(S): Transcatheter arterial embolization with N-butyl cyanoacrylate (NBCA). RESULT(S): An emergency cesarean section was performed for abruptio placentae. The neonate died on day 0. After the cesarean section, a hematoma was found at the uterine incision that continued to increase. Therefore, pelvic angiography was performed, and extravasation was observed from the uterine arteries. NBCA was used for embolization, and the extravasation stopped rapidly. Total transfusion volume was 10,190 mL. Nine months after the cesarean section, the patient became pregnant naturally and delivered a boy by elective cesarean section. CONCLUSION(S): For treatment of shock caused by perinatal hemorrhage, which is a major cause of perinatal mortality, even if clotting abnormalities are present, transcatheter arterial embolization using NBCA can provide effective hemostasis. Moreover, in patients who would otherwise require a hysterectomy, fertility can be preserved.

Risk factors for perioperative venous thromboembolism: A retrospective study in Japanese women with gynecologic diseases.

BACKGROUND: Patients with gynecologic cancer have a high risk of venous thromboembolism (VTE) like patients with other cancers. However, there is little information on risk factors for VTE during gynecologic surgery and no uniform preventive strategy. Our objectives were to identify risk factors for perioperative VTE in gynecologic patients and establish methods for prevention. METHODS: We analyzed 1,232 patients who underwent surgery at the Department of Obstetrics and Gynecology of St. Marianna University School of Medicine between January 2005 and June 2008. We investigated (1) risk factors for preoperative VTE, (2) use of an inferior vena cava (IVC) filter, and (3) risk factors for postoperative VTE. RESULTS: There were 39 confirmed cases of perioperative VTE (3.17%), including 25 patients with preoperative VTE and 14 with postoperative VTE. Thirty-two patients had cancer and seven patients had benign diseases. Twenty-two of the 32 cancer patients (68.7%) had preoperative VTE, while postoperative VTE occurred in 10 cancer patients. Multivariate analysis indicated that ovarian cancer, tumor diameter ≥10 cm, and previous of VTE were independent risk factors for preoperative VTE. Among ovarian cancer patients, multivariate analysis showed that an age ≥50 years, the presence of heart disease, clear cell adenocarcinoma, and tumor diameter ≥20 cm were independent risk factors for preoperative VTE. The factors significantly related to preoperative VTE in patients with benign disease included previous VTE, age ≥55 years, tumor diameter ≥20 cm, and a history of allergic-immunologic disease. Thirteen of the 25 patients (52%) with preoperative VTE had an IVC filter inserted preoperatively. Postoperative screening (interview and D-dimer measurement) revealed VTE in 14/1,232 patients (1.14%). Multivariate analysis indicated that cancer surgery, a history of allergic-immunologic disease, and blood transfusion ≥2,000 ml were independent risk factors for postoperative VTE. CONCLUSIONS: Perioperative VTE is often fatal and preventive measures should be taken in the gynecologic field, especially when patients have the risk factors identified in this study. Since VTE is often present before surgery, preoperative screening is important and use of an IVC filter should be considered.

Heterotopic autotransplantation of ovarian cortex in cynomolgus monkeys.

Abstract In recent years, removal of ova or ovaries before chemotherapy or radiation therapy has been investigated in young female cancer patients to avoid the adverse effects of treatment. Orthotopic autotransplantation of ovarian cortex has advantages such as easy collection of ova and the possibility of spontaneous pregnancy. Although children have been born after successful orthotopic autotransplantation into the residual ovaries, some patients cannot undergo this procedure such as those who need bilateral ovariectomy or pelvic radiation therapy, therefore it is still necessary to investigate suitable heterotopic autotransplantation sites. The present study was performed in primates (cynomolgus monkeys) with the objective of determining the optimum site for heterotopic autotransplantation of ovarian cortex to enhance the clinical application of this method. The retroperitoneal iliac fossa and omentum were selected as sites for heterotopic autotransplantation. Two cynomolgus monkeys were subjected to laparotomy under anesthesia. After resection of the bilateral adnexae, the ovaries were cut into 0.5 cm cubes that were transplanted. Blood levels of follicle-stimulating hormone, luteinizing hormone, estradiol, and progesterone were monitored, and monkeys with a regular estrus cycle underwent superovulation and egg collection. In both monkeys studied, recovery of a regular estrus cycle was confirmed after heterotopic autotransplantation of ovarian tissue. MII phase ova were successfully collected from tissues transplanted into the retroperitoneal iliac fossa or omentum. Development to the early blastocyst stage was confirmed after microfertilization. We established an appropriate method of heterotopic autotransplantation using ovarian cortex into the retroperitoneal iliac fossa or omentum in primates.

Cryopreservation of ovarian tissue after pretreatment with a gonadotropin-releasing hormone agonist.

PURPOSE: The purpose of this study was to investigate whether slow-rate freezing or vitrification is better for cryopreservation of ovary tissues pretreated with gonadotropin-releasing hormone agonist. METHODS: In this nonclinical study performed in rats, leuprorelin acetate was administered to female Wistar rats, aged 6-8 weeks. After confirming arrest of the estrous cycle by examination of vaginal smears, ovarian tissue was cryopreserved by vitrification and slow-rate freezing prior to thawing and autotransplantation. The time required for estrous cycle recovery was assessed from vaginal smears in each group starting from day 1 of transplantation. Estradiol levels were also monitored after transplantation. RESULTS: The estrous cycle recovered after transplantation of ovarian tissue frozen by either method, but recovery was significantly faster after transplantation of vitrified tissue. The estradiol level also recovered by 10 days after transplantation. CONCLUSIONS: Ovarian function was restored after transplantation of tissue preserved by either vitrification or slow-rate freezing after pretreatment with leuprorelin acetate. This method may be applicable for patients scheduled to undergo cryopreservation of ovarian tissue before chemotherapy.