月经周期对歼击机女飞行员辨色力的影响

目的：研究歼击机女飞行员月经周期中不同时相的辨色力变化情况。方法应用Far nswor th-Munsell 100(FM 100)色棋检查10名歼击机女飞行员、10名普通女性及10名歼击机男飞行员辨色力的变化,记录女性月经周期第2天（行经时相）、第10天（卵泡时相）、第22天（黄体时相）及男飞行员的色觉总错误分值。应用SPSS 16.0统计软件进行计量资料的单因素方差分析、独立样本t检验。结果月经周期相同时相中,女飞行员与普通女性的色觉总错误分值差异无统计学意义（P＞0.05）;无论是女歼击机飞行员还是普通女性,卵泡时相的色觉总错误分值最小,但任意两时相比较差异无统计学意义（P＞0.05）;女性（女飞行员和普通女性）任意月经周期时相中的色觉总错误分值均小于男飞行员,且差异有统计学意义（P＜0.05）。结论歼击机女飞行员在月经周期中卵泡时相的辨色力略好于其他两时相,女性飞行员辨色力好于男性飞行员。     

Changes in apparent diffusion coefficients in the normal uterus during different phases of the menstrual cycle

This study investigated the apparent diffusion coefficients (ADCs) of the uterine zonal structures (myometrium, endometrium and junctional zone) among reproductive women, and their changes during the menstrual cycle. Magnetic resonance (MR) images of seven healthy females (aged 24–31 years) were obtained during the periovulatory, luteal and menstrual phases. Diffusion-weighted imaging (DWI) was performed with a single-shot echo-planar imaging (EPI) sequence in the midsagittal plane of the uterus using three b-values (b = 0, 500 or 1000 s mm⁻²). The ADC values of the three uterine zonal structures were measured on an ADC map by placing two regions of interest (ROI) on the corresponding zonal structures. The average changes of ADC values (intra-individual ADC value variation) over three menstrual phases were 0.41 × 10⁻³ mm² s⁻¹ (range, 0.08–0.91) for myometrium, 0.55 × 10⁻³ mm² s⁻¹ (0.35–0.84) for endometrium, and 0.40 × 10⁻³ mm² s⁻¹ (0.18–0.59) for the junctional zone. The ADC values for myometrium and endometrium were lower in the menstrual phase, although there was some overlap of individual values. Interindividual variation in ADC value for a given zone or phase ranged from 0.48 × 10⁻³ mm² s⁻¹ to 0.85 × 10⁻³ mm² s⁻¹. Intermeasurement variation between the two ROIs ranged from 0 to 0.48 × 10⁻³ mm² s⁻¹ per measurement. The magnitude of these variations was comparable to reported differences between malignant and non-malignant tissues. These preliminary results, from a small number of subjects, suggest that the menstrual cycle and individual variation in pre-menopausal women should be considered when interpreting the ADC values of uterine structures.Diffusion-weighted imaging (DW) is an emerging functional imaging technique that is based on the diffusion of water molecules [1]. DWI can measure the apparent diffusion coefficient (ADC) of the water in tissue, which reflects its cell density, cellular oedema and microcirculation [1, 2]. Malignant tissue tends to have low ADC values, and so ADCs are increasingly used as a quantitative parameter to distinguish malignant tissue from non-malignant tissue [3–5]. Recent studies in gynaecological imaging have reported ADC values that were lower than normal in uterine cervical cancer, endometrial cancer and leiomyosarcoma [6–8].In pre-menopausal women, T₂ weighted images of the uterus, a three-layer zonal structure, change during the menstrual cycle [9–11]. When the variation in the appearance of the uterus on T₂ weighted images and the underlying physiological changes are considered, it seems possible that there might be variation of ADCs in the normal uterus during the menstrual cycle, which could affect the baseline ADC values used in the assessment of uterine abnormalities. Thus, the purpose of this study was to investigate the ADC values of each zonal structure in the uterus among reproductive women, and their variation in three different phases of the menstrual cycle.     

Assessment of patency capsule retention using MR diffusion-weighted imaging

Objectives

Evaluate the ability of MR diffusion-weighted imaging (DWI) to predict patency capsule retention in Crohn’s disease (CD).

Methods

Clinical and imaging data were prospectively reviewed for 80 CD patients following patency capsule administration and MR-DWI under institutional review board (IRB) approval with informed consent. Two radiologists separately assessed the presence/absence of restricted diffusion in the distal ileum. Apparent diffusion coefficients (ADC) from three regions of interest on the ileal wall were averaged. The association between restricted diffusion and retention, and sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. Ability of ADC to predict retention was assessed with receiver operating characteristic (ROC) curve analysis.

Results

Restricted diffusion in the distal ileum was associated with capsule retention (p?=?0.001, p?<?0.0001). Sensitivity, specificity, PPV and NPV of restricted diffusion for capsule retention were 100.0%, 46.2%, 30.0%, 100% and 100.0%, 56.9%, 34.9%, 100%, respectively, for two radiologists. Accuracy of ADC to predict retention was high (area under the curve?=?0.851, p?<?0.0001). An ADC of 1.47 mm²/s showed 90.0% sensitivity and 50.0% specificity for retention.

Conclusions

Sensitivity and NPV of restricted diffusion for patency capsule retention were 100%, suggesting that DWI may predict gastrointestinal tract capability to pass video camera endoscopy.

Key Points

? Capsule endoscopy enables assessment of the gastrointestinal mucosa in Crohn’s disease ? Prior patency capsule administration is recommended to evaluate gastrointestinal tract patency ? MR diffusion-weighted imaging may detect pathological constriction of the ileum ? Restricted diffusion in the distal ileum was associated with capsule retention ? MR-DWI may predict gastrointestinal tract capability to pass capsule endoscopy

     

Assessment of cerebral microembolism during percutaneous radiofrequency ablation of lung tumors using diffusion-weighted imaging

OBJECTIVE: It is well known that radiofrequency ablation generates microbubbles in the liver. We hypothesized that microbubbles generated during percutaneous radiofrequency ablation of lung tumors flow into the pulmonary veins and are distributed to the systemic arteries, as with radiofrequency ablation of liver tumors. To assess the risk of cerebral infarction during radiofrequency ablation of lung tumors, we performed diffusion-weighted imaging and, if possible, monitored microemboli in the carotid artery during radiofrequency ablation. SUBJECTS AND METHODS: We prospectively studied 20 patients (19 men and one woman) who underwent radiofrequency ablation of lung tumors. Pre- and postoperative MRI examinations were performed in all 20 patients, and during 17 radiofrequency ablation sessions, sonography was used to monitor whether microemboli were generated. RESULTS: Radiofrequency ablation was technically feasible for the treatment of selected pulmonary tumors. Microemboli, which were believed to represent microbubbles, were seen on sonography during three of the 17 radiofrequency ablation sessions. They were rarely observed when a lung tumor was small, the treatment session was brief, and the radiofrequency emission power was low. No new area of abnormal intensity was seen on postoperative MRI in all 20 patients. Although the microemboli were observed, MRI could not confirm infarction. CONCLUSION: We concluded that cerebral infarction as a result of microbubbles generated during radiofrequency ablation of lung tumors has a low possibility of becoming a clinical problem.     

Variations in performance in simple muscle tests at different phases of the menstrual cycle.

The effect of the menstrual cycle on the performance of women in sporting activities is a very confused subject. In this study, performances in simple muscle tests--the handgrip and standing long jump, were studied at three phases of the menstrual cycle--menstrual (day 1-4), follicular (day 12-14) and luteal (day 19-21). Within subject paired "t" testing showed that in the handgrip test, performance was significantly superior during the menstrual phase than those during both the follicular and luteal phases. In the standing long jump test, performance was again superior during the menstrual phase, although not significantly with respect to the luteal phase. This finding is discussed in terms of the reported effects of the menstrual cycle on sporting performance, the variation in the types of exercise, and the possible role of the female sex hormones.     

Physiological changes of the human uterine myometrium during menstrual cycle: preliminary evaluation using BOLD MR imaging

PURPOSE: To investigate the T2* values within the junctional zone and outer uterine myometrium and their changes during the menstrual cycle, and thus to evaluate their physiologic changes on blood oxygenation level-dependent (BOLD) magnetic resonance (MR) imaging. MATERIALS AND METHODS: Single-shot echo-planar imaging (EPI) was used to acquire T2*-weighted images (TR/TE = 1000 msec/23-150 msec) from 15 healthy females with a 1.5-T magnet. T2* values of both junctional zone and outer uterine myometrium were measured within a single breathhold and during three menstrual cycle phases (menstrual, periovulatory, and luteal phase). Signal intensities of uterine myometrium on T2-weighted images were also evaluated. RESULTS: T2* could successfully be calculated in 13 subjects. T2* values for the junctional zone were significantly lower than those of the outer myometrium at every phase(P < 0.001), and T2* values of both junctional zone (P < 0.05) and outer (P < 0.01). Myometrium in the menstrual phase was significantly lower than those in the other phases. On T2-weighted images, the signal intensity of the junctional zone was significantly lower than outer myometrium in every phase (P < 0.01), but there was no significant difference among menstrual cycle phases in both layers (P > 0.05). CONCLUSION: This preliminary study suggested that menstrual cycle changes of the uterine myometrium were shown by BOLD imaging. BOLD MR imaging may be an potential modality to investigate physiologic changes of the uterine myometrium during the menstrual cycle.     

Measuring performance during the menstrual cycle: a model using oral contraceptives

PURPOSE: The aim of the study was to use a low-dose oral contraceptive (OC) pill to generate consistent estrogen and progestogen concentrations and investigate the relationship between steroid hormone concentrations during the OC cycle and anaerobic performance. METHODS: Five female rowers taking a low-dose OC performed tests of anaerobic power (10-s all-out effort) and capacity (1000-m row) on the Concept IIC rowing ergometer at two time points in each of three OC cycles. These time points corresponded to high estrogen and high progestogen (pill day 16-18; TDH) and low estrogen and low progestogen (pill day 26-28; TDL). Blood samples were collected at rest and postexercise for the quantification of 17beta-estradiol (E2), progesterone (P4), glucose, triglyceride, and lactate concentrations. RESULTS: Endogenous E2 and P4 concentrations were not significantly different between testing days or OC cycles (P > 0.05). Peak power output was higher (P < 0.05) and 1000-m rowing ergometer time faster (P < 0.05) at TDL. Pre- and postexercise glucose concentrations were increased (P < 0.05) at TDL, whereas rest and postexercise plasma triglyceride concentrations were significantly (P < 0.05) lower during this time. CONCLUSIONS: This study found that alterations in anaerobic performance throughout the OC cycle occurred with improved performances corresponding to low estrogen and progestogen concentrations. The OC provided a consistent hormonal milieu reducing inter- and intra-individual variations in sex steroids and standardized all performance and metabolic variables across each OC cycle tested. Given that OC use has a high prevalence among female athletes and provides a controlled hormonal environment, it serves as a good model in which the acute effects of female sex steroids on exercise performance can be studied.     

Knee joint kinaesthesia and neuromuscular coordination during three phases of the menstrual cycle in moderately active women

An increased incidence of sports related injuries in the premenstrual phase as well as in the menstrual phase of the menstrual cycle has been described. This may be explained by alterations in proprioception and neuromuscular coordination due to hormonal variations. Prospective, within women analysis of knee joint kinesthesia and neuromuscular coordination were performed by repeated measures analysis of variance in three hormonally verified phases of three consecutive menstrual cycles. Thirty-two healthy, moderately active female subjects volunteered to participate in the study. Twenty-five of the subjects performed at least one hormonally verified menstrual cycle. A specially designed device was used to investigate knee joint kinaesthesia and neuromuscular coordination was measured with the square hop test. These tests were carried out in the menstrual phase, ovulation phase and premenstrual phase determined by hormone analyses in three consecutive menstrual cycles. An impaired knee joint kinaesthesia was detected in the premenstrual phase and the performance of square hop test was significantly improved in the ovulation phase compared to the other two phases. The results of this study indicate that the variation of sex hormones in the menstrual cycle has an effect on performance of knee joint kinaesthesia and neuromuscular coordination.     

Thin-section diffusion-weighted magnetic resonance imaging of the brain with parallel imaging

BACKGROUND: Thin-section diffusion-weighted imaging (DWI) is known to improve lesion detectability, with long imaging time as a drawback. Parallel imaging (PI) is a technique that takes advantage of spatial sensitivity information inherent in an array of multiple-receiver surface coils to partially replace time-consuming spatial encoding and reduce imaging time. PURPOSE: To prospectively evaluate a 3-mm-thin-section DWI technique combined with PI by means of qualitative and quantitative measurements. MATERIAL AND METHODS: 30 patients underwent conventional echo-planar (EPI) DWI (5-mm section thickness, 1-mm intersection gap) without parallel imaging, and thin-section EPI-DWI with PI (3-mm section thickness, 0-mm intersection gap) for a b value of 1000 s/mm(2), with an imaging time of 40 and 80 s, respectively. Signal-to-noise ratio (SNR), relative signal intensity (rSI), and apparent diffusion coefficient (ADC) values were measured over a lesion-free cerebral region on both series by two radiologists. A quality score was assigned for each set of images to assess the image quality. When a brain lesion was present, contrast-to-noise ratio (CNR) and corresponding ADC were also measured. Student t-tests were used for statistical analysis. RESULTS: Mean SNR values of the normal brain were 33.61+/-4.35 and 32.98+/-7.19 for conventional and thin-slice DWI (P>0.05), respectively. Relative signal intensities were significantly higher on thin-section DWI (P<0.05). Mean ADCs of the brain obtained by both techniques were comparable (P>0.05). Quality scores and overall lesion CNR were found to be higher in thin-section DWI with parallel imaging. CONCLUSION: A thin-section technique combined with PI improves rSI, CNR, and image quality without compromising SNR and ADC measurements in an acceptable imaging time.     

Transverse relaxation time values in MR imaging of normal breast during menstrual cycle

Magnetic resonance (MR) imaging of the breast has shown promise in the diagnosis of breast lesions. In prior studies the time of MR examination in the menstrual cycle was not taken into account. If alterations in transverse relaxation time (T2) values of ductal tissue did occur during the menstrual cycle, they would have a significant bearing on the timing of MR studies of the breast. This study demonstrated no apparent alteration in T2 values during the menstrual cycle of normal young volunteers.     

Assessment of diffusion-weighted MR imaging in liver fibrosis

PURPOSE: To assess whether hepatic fibrosis is associated with a restriction in the diffusion of water that can be analyzed with diffusion-weighted MR imaging (DWI) of the liver. MATERIALS AND METHODS: DWI was performed in 10 normal rats and 15 rats with liver fibrosis. Echo-planar DWI was performed in the living rats at 1.5 T and repeated immediately after the animals were killed. Afterwards the livers were explanted, fixed in Bouin solution, and imaged with a DW spin-echo sequence at 4.7 T. Fibrosis was quantified by densitometry on Sirius red-stained histological sections. RESULTS: In living rats the apparent diffusion coefficient (ADC) decreased with the severity of liver fibrosis (controls: 1535 +/- 294 mm(2)/second; CCl(4) (5 weeks) 1129 +/- 273 mm(2)/second; CCl(4) (9 weeks): 943 +/- 132 mm(2)/second; P = 0.002). An inverse correlation between ADC and liver fibrosis volume density was observed (r = -0.712, P < 0.001). In contrast, these findings were not observed in the rats after they were killed or in the fixated livers. CONCLUSION: Decreased ADC correlated with increased liver fibrosis in living rats, but not after death. These results suggest that restricted water diffusion cannot be assessed by DWI in liver fibrosis. Other factors, such as a decrease of perfusion, may explain the decrease of the hepatic ADC measured in vivo in rats with liver fibrosis.     

High-b-value diffusion-weighted MR imaging of suspected brain infarction

BACKGROUND AND PURPOSE: Recent technological advances in MR instrumentation allow acquisition of whole-brain diffusion-weighted MR scans to be obtained with b values greater than 1,000. Our purpose was to determine whether high-b-value diffusion-weighted MR imaging improved contrast and detection of signal changes in acute and chronic brain infarction. METHODS: We prospectively evaluated the MR scans of 30 subjects with a history of possible brain infarction on a 1.5-T MR imager with 40 mT/meter gradients (slew rate 150 T/m/s) by use of the following single-shot echo-planar diffusion-weighted MR sequences: 1) 7,999/ 71.4/1 (TR/TE/excitations, b = 1,000; 2) 999/ 88.1/3, b = 2,500; and 3) 7,999/ 92.1/4, b = 3,000. Diffusion-weighted MR imaging was performed in three orthogonal directions during all sequences. All subjects were scanned with fast fluid-attenuated inversion recovery (FLAIR) (10,006/145/2,200/1 [TR/TE/TI/excitations]) and fast spin-echo T2-weighted (3,650/95/3 [TR/TE/excitations], echo train length, 8). The diagnosis of brain infarction was established by clinical criteria. RESULTS: Twenty women and 10 men with a mean age of 67.7 years were enrolled in the study. One subject was excluded owing to poor image quality. Twelve of 29 subjects had a clinical diagnosis of acute infarction. All 12 had lesions that were hyperintense on diffusion-weighted images at all three b values; five were cortical and seven subcortical. There was increased contrast of all lesions on high-b-value scans (b = 2,500 and 3,000). Lesions that were hypointense on diffusion-weighted images were identified and evaluated at the three different b values. At b = 1,000, there were 19 hypointense lesions, whereas at b = 2,500 and 3,000 there were 48 and 55 lesions, respectively. On FLAIR and T2-weighted images, these low-signal lesions were predominantly chronic, subcortical, ischemic lesions and lacunar infarcts, but four chronic cortical infarcts, one porencephalic cyst, and one primary brain tumor were also found. Low-signal lesions were also noted to have increased contrast on high-b-value diffusion-weighted scans. CONCLUSION: High-b-value diffusion-weighted MR imaging (b = 2,500 or b = 3,000) had no impact on diagnosis of acute infarction. High-b-value diffusion-weighted MR imaging (b = 2,500) combined with diffusion-weighted MR imaging at b = 1,000 improves tissue characterization by increasing the spectrum of observed imaging abnormalities in patients with suspected brain infarction.     

体素内不相干运动扩散加权成像（IVIM-DWI）定量研究育龄期女性正常子宫月经周期内微循环变化

目的:探讨体素内不相干运动扩散加权成像(IVIM-DWI)定量测量正常子宫微循环灌注随月经周期变化的价值.方法:10例育龄期健康女性志愿者于经期(第3天)、增生早期(第7天)、增生晚期(第12天)、分泌早期(第17天)及经前期(第27天)行盆腔MRI扫描.扫描序列包括T1WI、T2 WI和IVIM.测量子宫内膜、结合带及外肌层的真实扩散系数(D)、假性扩散系数(D*)和灌注分数(f).比较月经周期各时间点D、D*及f值的差异,统计方法采用随机区组设计方差分析.结果:不同时间点间两两比较,子宫的三层结构中仅内膜的f值在经前期与增生早期以及结合带的f值在经前期与经期、经前期与增生早期间的差异具有统计学意义(P值分别为0.015、0.037、0.038),其余各时间点间f、D和D*值的差异无统计学意义(P＞0.05);内膜的f值自增生早期至经前期呈现先上升后下降的变化趋势,且在增生晚期达峰值.子宫3层结构间两两比较,在经期、增生早期、分泌早期和经前期,内膜与结合带、结合带与外肌层间D值的差异具有统计学意义(P值分别为0.048、0.024、0.009和0.014;0.029、0.001、0.004和0.000),且D值的大小为结合带＜内膜＜外肌层;除经期外,其它4期时子宫内膜与外肌层、结合带与外肌层间f值的差异均有统计学意义(P＜0.05);除经期和增生晚期,其它3期时子宫内膜与外肌层、结合带与外肌层间D*值的差异亦具有统计学意义(P＜0.05).结论:IVIM-DWI是非侵入性评价正常子宫在月经周期中微循环变化情况的有效方法.     

Comparison of peritoneal tumor imaging using conventional MR imaging and diffusion-weighted MR imaging with different b values

Purpose

The aim of this study was to evaluate the utility of DW MRI with two different b values in identifying peritoneal tumors in oncology patients.

Materials and methods

Nineteen patients with known malignancy underwent abdominal and pelvic MRI before surgery. MRI included free-breathing DWI with b values of 400 and 800 s/mm², T1-weighted fat-suppressed spoiled gradient-echo, T2-weighted fat-saturated turbo spin-echo, and 5-min delayed gadolinium-enhanced imaging. Two observers reviewed images for peritoneal tumors at ten anatomic sites within consensus. The results of laparatomy and histopathological evaluation were compared with MRI results. Sensitivity, specificity, and accuracy of identifying peritoneal metastases were calculated for conventional MRI, combined DWI with a b value of 400 s/mm² and conventional MRI, and combined DWI with a b value of 800 s/mm² and conventional MRI by consensus of two observers.

Results

One-hundred and twenty-five peritoneal metastasis sites were confirmed by surgical and histopathological findings. Conventional MRI alone identified 72 peritoneal metastases (sensitivity, 0.58; specificity, 0.87; accuracy, 0.67). Combined DWI with a b value of 400 s/mm² and conventional MRI revealed 106 peritoneal metastases (sensitivity, 0.85; specificity, 0.88; accuracy, 0.85). Finally, combined DWI with a b value of 800 s/mm² and conventional MRI revealed 103 peritoneal metastases (sensitivity, 0.83; specificity, 0.94; accuracy, 0.86).

Conclusion

DWI with a high b value provides complementary information that can improve the detection of peritoneal tumors when combined with conventional MRI. We recommend combined MRI and DWI with a high b value for increasing the sensitivity and accuracy of the preoperative detection of peritoneal tumors.