Correlation between estimates of tumor perfusion from microbubble contrast-enhanced sonography and dynamic contrast-enhanced magnetic resonance imaging.

OBJECTIVE: We compared measurements of tumor perfusion from microbubble contrast-enhanced sonography (MCES) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in an animal tumor model. METHODS: Seven mice were implanted with Lewis lung carcinoma cells on their hind limbs and imaged 14 days later with a Philips 5- to 7-MHz sonography system (Philips Medical Systems, Andover, MA) and a Varian 7.0-T MRI system (Varian, Inc, Palo Alto, CA). For sonographic imaging 100 microL of a perfluoropropane microbubble contrast agent (Definity; Bristol-Myers Squibb Medical Imaging, Billerica, MA) was injected and allowed to reach a pseudo steady state, after which a high-mechanical index pulse was delivered to destroy the microbubbles within the field of view, and the replenishment of the microbubbles was imaged for 30 to 60 seconds. The MRI included acquisition of a T(10) map and 35 serial T(1)-weighted images (repetition time, 100 milliseconds; echo time, 3.1 milliseconds; alpha, 30 degrees ) after the injection of 100 microL of 0.2-mmol/kg gadopentetate dimeglumine (Magnevist; Berlex, Wayne, NJ). Region-of-interest and voxel-by-voxel analyses of both data sets were performed; microbubble contrast-enhanced sonography returned estimates of microvessel cross-sectional area, microbubble velocity, and mean blood flow, whereas DCE-MRI returned estimates of a perfusion-permeability index and the extravascular extracellular volume fraction. RESULTS: Comparing similar regions of tumor tissue seen on sonography and MRI, region-of-interest analyses revealed a strong (r(2) = 0.57) and significant relationship (P < .002) between the estimates of perfusion obtained by the two modalities. CONCLUSIONS: Microbubble contrast-enhanced sonography can effectively depict intratumoral heterogeneity in preclinical xenograft models when voxel-by-voxel analysis is performed, and this analysis correlates with similar DCE-MRI measurements.     

Quantification of tumor vascularity with contrast-enhanced sonography: correlation with magnetic resonance imaging and fluorodeoxyglucose autoradiography in an implanted tumor.

OBJECTIVE: To correlate the quantitated tumor vascularity of implanted murine tumors as depicted by contrast-enhanced sonography with estimates made with magnetic resonance imaging and with estimates of the percentage of viable (metabolically active) tumor as depicted by fluorodeoxyglucose autoradiography. METHODS: Implanted tumors in 10 mice were imaged with contrast-enhanced sonography, magnetic resonance imaging, and fluorodeoxyglucose autoradiography. Tumor vascularity was estimated with each modality and compared with the percentage of viable tumor. RESULTS: Quantitated estimates of tumor vascularity with contrast-enhanced sonography closely correlated (r = 0.95) with estimates made by magnetic resonance imaging and with the percentage of viable tumor (r = 0.93) as depicted by fluorodeoxyglucose autoradiography. CONCLUSIONS: Contrast-enhanced sonography accurately depicts tumor vascularity in these implanted tumors. Tumor vascularity correlated with the amount of metabolically active tumor.     

Rudimentary horn pregnancy: first-trimester prerupture sonographic diagnosis and confirmation by magnetic resonance imaging.

OBJECTIVE: Two cases of rudimentary horn pregnancy diagnosed in the first trimester by sonography and confirmed by magnetic resonance imaging (MRI) are reported. We suggest criteria for early, prerupture sonographic diagnosis of this rare condition. METHODS: We report a case in which pregnancy in a rudimentary horn was suspected on routine sonographic examination. In the second case, sonographic examination at 11 weeks' gestation revealed a right unicornuate uterus and a noncommunicating left rudimentary horn containing a gestational sac. In both cases, MRI clearly confirmed the sonographic diagnosis, showing an empty cavity of the uterine body and a pregnant uterine horn without an endometrial communication to the uterine body. RESULTS: Both patients underwent surgery, and the pregnant rudimentary horns were resected with no complications. CONCLUSIONS: We suggest the following criteria for sonographic diagnosis of rudimentary horn pregnancy: (1) a pseudopattern of a asymmetrical bicornuate uterus, (2) absent visual continuity tissue surrounding the gestational sac and the uterine cervix, and (3) the presence of myometrial tissue surrounding the gestational sac. Typical hypervascularization of placenta accreta may support the diagnosis. Additionally, MRI can be used to confirm the diagnosis before an invasive procedure is undertaken.     

Sonographic and magnetic resonance imaging findings in uterine incarceration

We show the sonographic and magnetic resonance imaging features of uterine incarceration. Clinical data and imaging findings were retrospectively reviewed for 8 confirmed cases identified by sonography from 2000 to 2010. Two patients had magnetic resonance imaging. Seven of 8 patients (87.5%) presented with abdominal pain; 4 of 8 (50.0%) also had urinary symptoms. All had a retroverted uterus with an elongated anterosuperiorly displaced or poorly visualized cervix on sonography. Magnetic resonance imaging showed similar features, but in both cases, the placental position was misinterpreted because of severe uterine retroversion. Radiologists should be aware of this condition and its imaging features to reduce associated morbidity and mortality.     

Sonographic findings of pectoralis major tears with surgical, clinical, and magnetic resonance imaging correlation in 6 patients.

OBJECTIVE: The purpose of this research was to describe the sonographic findings of pectoralis major injuries with clinical, surgical, and magnetic resonance imaging (MRI) correlation. METHODS: Images from sonographic examinations of the pectoralis major muscle of 6 patients were retrospectively evaluated and characterized. The sonographic findings were compared with clinical, surgical, and MRI findings. RESULTS: The 6 patients were male (mean age, 30 years) with injuries sustained during weight lifting, football, and shotgun firing. Two of the 6 patients had MRI correlation; 1 had surgical correlation; 2 had both surgical and MRI correlation; and 1 had clinical follow-up. The sternal head was injured in 5 patients; 4 involved the musculotendinous junction, and 1 involved the distal tendon. The sonographic findings of muscle fiber retraction and surrounding hemorrhage allowed identification of the affected muscle. Direct impact injury causing hematoma involved the clavicular head in 1 patient. In total, 5 cases were partial-thickness pectoralis major tears, whereas complete distal tendon disruption was found in 1. CONCLUSIONS: Sonographic imaging longitudinal to the pectoralis muscle fibers showed fiber disruption, retraction, and possible hypoechoic or anechoic hematoma, most commonly involving the musculotendinous junction of the sternal head. Distal tendon assessment is important to evaluate for a full-thickness pectoralis major tear.     

Measuring tumor perfusion in control and treated murine tumors: correlation of microbubble contrast-enhanced sonography to dynamic contrast-enhanced magnetic resonance imaging and fluorodeoxyglucose positron emission tomography.

OBJECTIVE: The purpose of this study was to evaluate the ability of dynamic microbubble contrast-enhanced sonography (MCES), in comparison with dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and fluorodeoxyglucose positron emission tomography (FDG-PET), to quantitatively characterize tumor perfusion in implanted murine tumors before and after treatment with a variety of regimens. METHODS: Seventeen mice with Lewis lung carcinoma implants were categorized to control, radiation therapy alone, antiangiogenic chemotherapy alone, and combined chemoradiation. On day 0 of each treatment regimen, MCES and DCE-MRI of each tumor were performed. On day 5 of treatment, dynamic FDG-PET, MCES, and DCE-MRI were performed. RESULTS: Microbubble contrast-enhanced sonography showed that intratumoral perfusion, blood volume, and blood velocity were highest in the untreated control group and successively lower in each of the treatment groups: radiation therapy alone resulted in a two-thirds reduction of perfusion; antiangiogenic chemotherapy resulted in a relatively larger reduction; and combined chemoradiotherapy resulted in the largest reduction. Microbubble contrast-enhanced sonography revealed longitudinal decreases in tumor perfusion, blood volume, and microvascular velocity over the 5-day course of chemoradiotherapy (all P < .01); conversely, these values rose significantly for the untreated control tumors (P < .01). Dynamic contrast-enhanced MRI showed a smaller and statistically insignificant average decrease in relative tumor perfusion for treated tumors. Dynamic PET revealed delayed uptake of FDG in the tumors that underwent chemoradiotherapy. CONCLUSIONS: Microbubble contrast-enhanced sonography is an effective tool in the noninvasive, quantitative, longitudinal characterization of neovascularization in murine tumor models and is correlative with DCE-MRI and FDG-PET. Microbubble contrast-enhanced sonography has considerable potential in the clinical assessment of tumor neovascularization and in the assessment of the response to treatment.     

Placenta accreta: Imaging by gray-scale and contrast-enhanced color Doppler sonography and magnetic resonance imaging

Antepartum diagnosis of placenta accreta on the scarred myometrium of the isthmus uteri after previous cesarean section was made in 2 pregnancies. Antepartum sonographic examination revealed abnormal bulging of placental tissue toward the bladder cavity and arcuate arteries within the bladder wall. Magnetic resonance imaging revealed the depth and extent of placental invasion into the myometrium of the isthmus and the bladder muscular layer. Low-resistance pulsatile intervillous flow was recorded within the placenta in 1 case. Both magnetic resonance imaging and contrast-enhanced color Doppler sonography were informative in the other of these cases, in which the patient was conservatively managed during pregnancy and after delivery. © 1998 John Wiley & Sons, Inc. J Clin Ultrasound 26 : 90–94, 1998.     

Benign endometrial adenofibroma and polyp in patients receiving tamoxifen: findings on transvaginal ultrasonography and magnetic resonance imaging

Tamoxifen, a selective estrogen receptor modulator, is widely used to treat breast cancer, but an association has been reported between tamoxifen and the development of endometrial lesions, including endometrial carcinoma, endometrial polyps, and endometrial hyperplasia. There have also recently been a few reports on the relation between tamoxifen and adenofibroma. We present two case reports, one of a patient with a uterine adenofibroma and one of a patient with an endometrial polyp, both of whom received tamoxifen. Cases 1 and 2 are 75- and 65-year-old postmenopausal women, respectively, undergoing tamoxifen therapy. In both cases, endometrial thickening and many small cysts in the uterine cavity were revealed by transvaginal ultrasonography or magnetic resonance imaging. Postoperative microscopic examination confirmed the mass as an adenofibroma in case 1 and as an endometrial polyp in case 2.     

Fetal magnetic resonance imaging in the evaluation of fetuses referred for sonographically suspected abnormalities of the corpus callosum.

OBJECTIVE: Fetal magnetic resonance imaging (MRI) has been shown to be useful in assessing the developing central nervous system. However, its utility in specific brain disorders has not been well investigated. We hypothesized that fetal MRI can better assess the integrity of the brain in cases with sonographically suspected callosal abnormalities. METHODS: We retrospectively reviewed fetal MRI and prenatal sonographic studies of 10 fetuses referred for MRI for sonographically suspected callosal abnormalities. RESULTS: An abnormal corpus callosum was identified on fetal MRI in 80% of cases. The type of callosal abnormality (complete or partial agenesis) was similar on both prenatal sonography and fetal MRI in all cases. All sonographically identified additional brain abnormalities were detected on fetal MRI, with the exception of choroid plexus cysts. Furthermore, in 63% (5 of 8) of cases with a callosal abnormality on both sonography and fetal MRI, additional brain abnormalities were detected on fetal MRI that were not apparent on sonography. These sonographically occult findings were confirmed on postnatal MRI or autopsy in 3 of 5 patients. CONCLUSIONS: Fetal MRI is an important adjunct to sonography in assessing the corpus callosum and other aspects of brain development when agenesis of the corpus callosum is suspected. It can identify frequent additional findings that are not visible on sonography such as abnormal sulcation. In light of the association between additional brain abnormalities and worse neurodevelopmental outcome, the potential of fetal MRI as an important adjunctive prognostic imaging test in fetuses with callosal agenesis can now be tested.     

The role of magnetic resonance imaging in the evaluation of isolated mild ventriculomegaly.

OBJECTIVE: Isolated mild ventriculomegaly is defined as dilatation of the lateral ventricle from 10 to 15 mm, with no other structural abnormalities observed at the time of diagnosis. Its reported frequency is between 1 per 50 and 1 per 700 deliveries. There are no universal recommendations for evaluation of isolated mild ventriculomegaly. Targeted sonography, karyotype analysis, and viral antigen testing, particularly for cytomegalovirus, are most often used for further investigation of this finding. We studied the role of magnetic resonance imaging as part of the prenatal evaluation of isolated mild ventriculomegaly. METHODS: Thirty-six pregnant women were referred to 2 Hadassah hospitals between 1999 and 2002 for evaluation of isolated mild ventriculomegaly. They underwent targeted sonography to exclude other anomalies, genetic amniocentesis for fetal karyotype, and serologic cytomegalovirus tests. Mild ventriculomegaly was the only pathologic finding diagnosed. Fetal brain magnetic resonance imaging was performed to evaluate the correlation between sonographic and magnetic resonance imaging findings and the additional contribution of magnetic resonance imaging in evaluating isolated mild ventriculomegaly. RESULTS: Thirty-six magnetic resonance imaging studies were performed. All tests were adequate for evaluation. In 3 (8.3%) of 36 cases, magnetic resonance imaging showed additional findings: in a severely obese woman, ventricular dilatation up to 18 mm and periventricular cystic lesions with abnormal sulcation suggestive of diffuse parenchymal abnormality were diagnosed, and in 2 cases, bleeding in germinal centers was found. On subsequent sonographic examination, no other finding but isolated mild ventriculomegaly was diagnosed. In the remaining 33 women (91.7%), magnetic resonance imaging studies correlated well with sonographic findings. Further sonographic follow-up in this subgroup failed to reveal any other pathologic findings. CONCLUSIONS: Our study supports the view that magnetic resonance imaging should be considered as part of the evaluation of isolated mild ventriculomegaly, especially when objective difficulties preclude detailed sonographic examination.     

心血管MRI第二部分--心血管MRI的基本序列和常用技术

此文为第二部分,着重介绍心血管MRI(CMRI)的基本对比、序列及要求。首先,归纳CMRI的三种基本快速成像序列和图像的对比分类。然后,应对CMRI的技术挑战和难点,讲述CMRI质量控制的常用技术。     

以精神症状为首发的神经梅毒临床和影像分析

目的：探讨以精神症状为首发的神经梅毒的临床及头颅磁共振成像(MRI)表现。方法对2010年1月至2013年6月以精神症状为首发症状的8例神经梅毒患者进行回顾性分析。结果8例患者均被误诊为双向情感障碍、焦虑症、脑炎等,部分患者同时伴有反应迟钝、认知能力明显下降。所有患者血清快速血浆反应素环状卡片试验(RPR)及梅毒螺旋体血球凝集试验(TPHA)均阳性。8例 MRI 均有异常表现,脑部多发的缺血灶5例,其中表现为脑炎样改变2例;混合型2例,表现为额、颞叶萎缩;局部脑膜增厚1例。结论神经梅毒临床和 MRI 表现缺乏特征性,临床易误诊,当常规治疗效果不佳时,应进行梅毒血清学检查,考虑神经梅毒可能。     

脑活动功能磁共振成像研究进展

本文介绍了人脑活动功能磁共振成像(fMRI)的生物物理基础研究的现状和关键技术的进展,综述了这些技术在人脑功能研究和临床疾病诊疗中的应用和发展前景.     

Clinical utility of sonography in diagnosing plantar fasciitis.

OBJECTIVE: The purpose of this study was to investigate the efficacy of sonography in the detection of plantar fasciitis (PF) compared with magnetic resonance imaging (MRI) findings in subjects with inferior heel pain. METHODS: Seventy-seven patients with unilateral (n = 9) and bilateral (n = 68) heel pain were studied. Seventy-seven age- and sex-matched asymptomatic subjects served as a control group. Magnetic resonance imaging was used to establish a diagnosis of PF with sagittal T1-weighted, T2-weighted, and short tau inversion recovery sequences. The sonographic appearances of PF were compared with MRI findings. Plantar fascia and heel pad thickness were also measured on both imaging modalities. RESULTS: Compared with MRI, sonography showed 80% sensitivity and 88.5% specificity in assessing PF. A strong correlation was found between plantar fascia and fat pad thickness measurements done by sonography (P < .001; r = 0.854) and MRI (P < .001; r = 0.798). Compared with the asymptomatic volunteers, patients with PF had significant increases in plantar fascia and heel pad thicknesses, weight, and body mass index (P = .0001). Heel pad thickness was also significantly increased with pain duration (P = .021). CONCLUSIONS: Although MRI is the modality of choice in the morphologic assessment of different plantar fascia lesions, sonography can also serve as an effective tool and may substitute MRI in the diagnosis of PF.     

Pacing in high field cardiac magnetic resonance imaging:

Currently, cardiac MRI is contraindicated in patients with an implanted pacemaker or ICD due to safety hazards. However, MRI is promising to play a key role in cardiac diagnostics in near future. This study examined a rat with an implanted pacemaker pacing at a rate of 460/min with high field cardiac MRI. This study showed that pacing during cardiac imaging at 7 Tesla was possible. The pacemaker program was not disturbed by the high field or the strong gradients (maximum dB/dt 400 mT/s). The only noticeable effect on the MRI signal was a signal void of 2 cm around the device.     

磁共振成像对胆管癌的诊断价值

目的 探讨胆管癌的MRI和MRCP表现，评价MRI结合MRCP对胆管癌的诊断价值。方法 对62例经手术病理证实的胆管癌，回顾性分析其MRI和MRCP表现。结果 肝内胆管癌11例表现为肝内不规则长T1、长T2浸润性信号，增强后呈中度环形强化。肝门胆管癌16例，MRI主要表现为肝内胆管扩张，在肝门部胆管突然截断、中断或充盈缺损，肝门部软组织肿块。肝外胆管癌35例，MRI表现为肝内胆管软藤样扩张，胆总管不同部位完全性梗阻。MRCP可显示扩张的肝内外胆管及梗阻部位的狭窄、中断、截断和管腔内的充盈缺损。结论 MRI和MRCP联合应用能较好地对胆管癌进行诊断，并能准确描述和评价胆管癌扩散及浸润范围。