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.     

MR imaging of diffuse adenomyosis changes after GnRH analog therapy

PURPOSE: To evaluate uterine changes on MRI before and after GnRH analog (GnRHa) treatment in diffuse adenomyosis. MATERIALS AND METHODS: Thirty-one patients with MRI features suggestive of diffuse adenomyosis received GnRHa for 6 months. Diffuse adenomyosis was sub-classified as: symmetric (symmetric/ entire widening of the junctional zone [JZ]) and asymmetric (asymmetric/ partial widening of JZ). Pre- and post-high signal intensity (SI) foci and JZ width, and post-demarcated change (interface of adenomyosis with the myometrium became more discrete with a concomitant decrease in JZ width) were analyzed. RESULTS: Before therapy, 15 of 18 asymmetric contained high SI foci compared to none of symmetric. After therapy, JZ width decreased (P < 0.0001). Eight asymmetric and none of symmetric showed demarcated change with resolved high SI foci. CONCLUSION: Our results suggest the use of GnRHa is associated with a decrease of JZ width in adenomyosis. Asymmetric adenomyosis with high SI foci appears to be the most sensitive to hormonal therapy.     

Early identification of sites of embryo implantation in rats by means of gadolinium-enhanced MR imaging

To determine if magnetic resonance (MR) imaging techniques can be used to examine sites of embryo implantation in intact rats, pregnant animals were imaged with gadopentetate dimeglumine-enhanced MR imaging approximately 10 hours after initiation of implantation on day 5 of pregnancy. T1-weighted, three-dimensional SPGR (spoiled gradient-recalled acquisition in the steady state) sequences were used to image the volume of abdomen containing the uterine horns before and after injection of gadopentetate dimeglumine into a femoral venous catheter. While unenhanced images provided little detail in uterine tissue, analysis of the gadolinium-enhanced abdominal images with interactive vascular imaging allowed easy identification of sites of embryo implantation along both uterine horns in four of four pregnant rats. These punctate patterns of enhancement match those of macroscopic bluing after injection of Evans blue dye. Similar gadolinium-enhanced MR imaging of nonpregnant rats produced only a slight, generalized enhancement of entire uterine horns. The authors conclude that local increases in extracellular fluid volume, vascular permeability, and blood flow in the uterus may all contribute to the gadolinium enhancement of the implantation sites. They propose that this approach can be used in experimental settings to provide information regarding embryo implantation unaccessible with traditional approaches. In clinical settings, gadolinium-enhanced MR imaging may be used to examine potential causes of infertility, including luteal phase defects.     

Granulomatous prostatitis: a pitfall in MR imaging of prostatic carcinoma

Granulomatous prostatitis is an uncommon disease that can prostatic carcinoma on both digital rectal examination and transrectal ultrasound. Four patients who underwent magnetic resonance imaging of the prostate had a histological diagnosis of graanulomatous prostatitis; three of them had recent urinary tract infections. The other patient had an associated midline prostatic cyst and a focus of malignancy. T1-and T2-weighted spin-echo images were obtained in all cases. Peripheral zone lesions of decreased signal intensity, suggestive of carcinoma,were found in all four patients on T2-weighted images. Granulomatous prostatitis should be considered in the differential diagnosis of low signal intensity areas with prostatic magnetic resonance imaging. Correspondence to; P.A. Gevenois     

MR evaluation of cervical cancer in hysterectomy specimens: Correlation of quantitative T2 measurement and histology

Specimens from modified radical hysterectomies performed for invasive carcinoma of the cervix were analyzed with quantitative T2 magnetic resonance (MR) imaging and histologic study to determine to what degree there was a correlation between the findings of the two modalities. The mean T2 of cervical stroma was 48 msec, while the outer zone of the cervix had a mean T2 of 62 msec and the central canal region typically had T2 values of 115 msec ± 20 (standard deviation). A total of nine cervical cancers were analyzed, and their mean T2 value was 79 msec. Separation between cervical stroma and tumor was good, with stromal T2 values ranging from 30 to 66 msec, while tumor T2s ranged from 60 to 97 msec. Statistical analysis indicated that these data were associated with a sensitivity of 89% and a specificity of 95%, with 95% confidence intervals of [50%,99.4%] and [74%,99.7%], respectively, for separating tumor from stroma on the basis of T2 value. Quantitative T2 imaging was found to provide an effective, nonsubjective means of classifying cervical anatomy and neo-plastic disease.     

Thin-section MR imaging of rat brain at 4.7 T.

The brains of anesthetized 7-month-old male hooded rats were imaged in coronal, sagittal, and horizontal planes at 4.7 T. Images were obtained with a section thickness of 0.6 mm and in-plane pixel size of 0.18-0.20 mm, resulting in finer combined spatial and contrast resolution than in most previously published reports. This allowed detailed anatomic assignment of many brain structures on the basis of comparison with a histologic brain atlas. T1, apparent T2, and water proton density values of gray matter, white matter, and cerebrospinal fluid (CSF) were derived from saturation-recovery and multi-echo measurements. These values were used to calculate expected contrast-to-noise ratios as a function of TR and TE in spin-echo imaging sequences. The optimal simultaneous contrast between gray and white matter and between CSF and gray matter was obtained on images with moderate T2 weighing, with a TR of 3.6 seconds and a TE of 45 msec. The use of thin sections was found to be essential for resolving many fine structures, and the improved sensitivity provided by the high magnetic field strength was crucial for imaging such thin sections at adequate signal-to-noise ratios.     

MR imaging of myositis ossificans: Variable patterns at different stages

Five patients with a palpable mass at presentation underwent magnetic resonance (MR) imaging. The final diagnosis was myositis ossificans (MO). MR imaging features, particularly after injection of gadopentetate dimeglumine, mimicked those of an inflammatory mass or neoplasm. The lesions were excised in three patients, and the Images were correlated with histologic findings. Three different appearances were noted on MR images, corresponding to the stages of maturation of MO. Two cases Involved early-stage lesions, and Tl-weighted MR images showed a mass with homogeneous intermediate signal intensity. Both lesions showed rim enhancement after contrast agent injection and high signal intensity on T2-weighted images. Pathologic specimens demonstrated stroma with masses of spindle cells in which osteoid production was interspersed. The enhanced rim of the lesion mimicked the expected MR appearance of an abscess or necrotic tumor. Areas of enhancement in adjacent muscle were also seen on postcontrast T1-weighted images. Intermediate-stage MO was present in one case; there was evidence of a thin rim of calcification on plain radiographs and fatty changes in the lesion on T1-weighted Images, corresponding with histologic findings. One case of a mature lesion showed a considerable degree of peripheral calcification both on MR images and at histology. MR imaging is nonspecific in the diagnosis of early-stage MO.     

MR imaging of the uterus and cervix in healthy women: Determination of normal values

The purpose of this study was to establish normal values for the volume of the uterus and cervix in MRI based on age and the menstrual cycle phase. We performed MRI of the pelvis in 100 healthy women. For the uterus, they were further divided into two groups: one with myomas and/or adenomyosis and one without either. The volume of the uterus and cervix and thickness of the uterine wall layers were analysed by age and the menstrual cycle phase. The mean volume of the uterus in both groups and the cervix significantly increased with age to reach its peak at 41–50 years, and then dropped. Likewise, the thickness of the endometrium and the junctional zone, but not the myometrium, significantly increased until 41–50 years, and then decreased. When we compared the volume of the uterus and cervix and the thickness of the uterine wall layers between the two phases of the menstrual cycle, we found no significant differences. The volume of the uterus and cervix and the thickness of the endometrium and junctional zone differ significantly with age, but not between the two phases of the menstrual cycle. Knowledge of MRI-related normal values can be expected to aid the early identification of uterine pathologies.     

Efficacy of contrast-enhanced MR imaging in cardiomyopathy: an experimental study using Bio14.6 hamsters

RATIONALE AND OBJECTIVES: Myocardial fibrosis was evaluated with magnetic resonance (MR) imaging in Bio14.6 hamsters. MATERIALS AND METHODS: Gated gradient-echo T1-weighted images and spin-echo images with gadopentetate dimeglumine enhancement (0.2 mmol/kg) were obtained. RESULTS: Myocardial enhancement persisted for 13 minutes after administration of gadopentetate dimeglumine, and myocardial signal intensity peaked at 13 minutes on gradient-echo T1-weighted images. The enhanced areas were greater in Bio14.6 hamsters at 25-42 weeks than at 10 weeks. Pathologic data revealed enhancement with inflammation at 10 weeks and fibrosis with vessel proliferation at 25-42 weeks. Pathologic fibrotic change was greater at 32-42 weeks than at 10 weeks. The myocardium of 42-week-old Bio14.6 hamsters showed remarkable contrast enhancement, which continued for 13 minutes. There was no correlation between gadolinium enhancement and pathologic findings in the evaluation of myocardial degeneration and fibrosis. CONCLUSION: Gadolinium-enhanced MR imaging was useful for estimating myocardial fibrotic changes with vessel proliferation and myocardial damage.     

MR imaging of normal rat brain at 0.35 T and correlated histology.

A custom-built small-animal transceiver was used for in vivo imaging of normal rat brain at 0.35 T, with the objective of identifying anatomic components by comparison of images with corresponding histologic sections. The cerebrum, cerebellum, brain stem, ventricles, hippocampus, and subarachnoid space were identified and cerebrospinal fluid (CSF) was differentiated from gray matter and white matter on coronal and transaxial magnetic resonance (MR) images. These images compare favorably with those obtained by others at higher field strengths in regard to delineating major neuroanatomic structures. It is concluded that this technique will be useful for investigating small-animal models of human neurologic disease involving morphologic and morphometric changes in gray matter, white matter, and CSF-filled spaces.     

Transient uterine contraction mimicking adenomyosis on MRI

Transient myometrial contraction as a physiological phenomenon may simulate pathological conditions, such as a focal or diffuse adenomyosis. Clinicians should be aware of the potential presence of this phenomenon and imaging should be repeated after a suitable interval when the nature of a bulge or a region of low intensity in the myometrium is in doubt. In this paper, we report a transient myometrial contraction that mimics an adenomyosis, but disappears in repeated series. Received 10 February 1997; Revision received 9 April 1997; Accepted 21 May 1997     

Differentiation of the various lesions causing an abnormality of the endometrial cavity using MR imaging: emphasis on enhancement patterns on dynamic studies and late contrast-enhanced T1-weighted images

The objectives of this study were to determine the usefulness of magnetic resonance (MR) imaging in the differentiation of various lesions causing an abnormality of the endometrial cavity by evaluating the imaging features on dynamic contrast-enhanced study and late contrast-enhanced T1-weighted images (T1WI). Contrast-enhanced MR imaging of 59 pathologically proven lesions that showed an abnormality of the endometrial cavity, including 32 endometrial cancers, five sarcomas, nine hyperplastic polyps, nine submucosal myomas, three hyperplasia, and one adenomyoma, were retrospectively reviewed. The enhancement degree and patterns on dynamic contrast-enhanced study and late contrast-enhanced T1WI were compared among different pathologies. On dynamic contrast-enhanced study, 72% (23/32) of endometrial cancers showed early peak enhancement to be reached within 1 min following intravenous administration of contrast material. On late-contrast-enhanced T1WI, lesions showed weak enhancement with gradual washout. Ninety-five percent (21/22) of benign lesions and 100% (5/5) of sarcomas showed late peak enhancement to be reached in 2–3 min following intravenous administration of contrast material. On late contrast-enhanced T1WI, both of these lesions showed persistent strong enhancement. Different enhancement patterns on dynamic contrast-enhanced MR imaging and late contrast-enhanced T1WI can provide a useful clue in the differentiation of various lesions causing an abnormality of the endometrial cavity.     

Liver metastases from pancreatic adenocarcinoma: MR imaging characteristics

PURPOSE: To describe the magnetic resonance imaging spectrum of appearances of liver metastases from pancreatic ductal adenocarcinoma. MATERIALS AND METHODS: We retrospectively evaluated the MRI exams performed between July 1996 and August 2001 in all patients who had liver metastases from pancreatic adenocarcinoma and histopathologic diagnosis from either the primary pancreatic tumor, liver metastases, or both. Sixteen patients were included in the study. All MR studies were performed at 1.5 T with a standard protocol including T1- and T2-weighted images and serial post-gadolinium spoiled gradient echo (SGE) images. Location, size, number, signal characteristics on T1- and T2-weighted images, and pattern of enhancement on serial gadolinium-enhanced SGE images were assessed. RESULTS: The diameter of metastases ranged from a few millimetres to 4 cm, and 12 patients (75%) had only lesions of 1.5 cm or less. Capsular-based liver metastases were found in 13 patients (81%) and three patients had only capsular-based lesions with a diameter under 1.5 cm. Hypervascular lesions were found in six patients (38%) and hypovascular lesions in 10 patients (62%). Perilesional enhancement was present in 10 patients (62%), with six patients (38%) having ring perilesional enhancement and eight patients (50%) having wedge-shaped perilesional enhancement. CONCLUSION: On MR imaging, hepatic metastases from pancreatic adenocarcinoma show a range of enhancement patterns. Hypervascular metastases are not rare. Capsular based distribution, small diameter, and perilesional enhancement are common features. This retrospective study describes the MR imaging spectrum of appearances of liver metastases from pancreatic adenocarcinoma in patients with histopathologic confirmation of the diagnosis.     

Primary Uterine Lymphoma: A Case Report

Primary lymphoma of the uterus is a rare disease, the reported characteristic MR imaging findings being homogeneous intermediate signal intensity of the indistinct mass on T1- and T2-weighted images, and the preservation of endometrial lining and uterine architecture. We report a case of primary uterine lymphoma which showed tumoral necrosis, endometrial disruption and diffuse anterior vaginal wall involvement.     

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse muscu-loskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1 -weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1weighted, gadopentetate dimeglu-mine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibro-myalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.     

MR imaging findings of uterine endometrial stromal sarcoma: differentiation from endometrial carcinoma

Endometrial stromal sarcoma (ESS) is a rare malignant neoplasm of the uterus. We retrospectively analyzed pelvic MR imaging in 8 cases of ESS to determine the characteristic MR findings of ESS. Magnetic resonance images of 8 cases of ESS were evaluated for findings including the size, margin of the tumor, nodular lesions at the tumor margin, intramyometrial worm-like nodular extension, multiple nodular mass formation, hemorrhage, and necrosis in the tumor. The degree of contrast enhancement was also analyzed. The MR imaging findings of 21 consecutive cases of endometrial carcinoma (EC) were also evaluated and compared with those of ESS. The mean and the standard deviation of the maximum diameter of ESS and EC were 8.80 ± 4.99 and 3.93 ± 2.47 cm, respectively. Increased enhancement in at least a part of the tumor was observed in five of the six analyzed ESS cases and in 2 of 12 analyzed EC cases. The irregular margin, nodular lesions at the margin, intramyometrial nodular extension, and multiple nodular mass formation were more frequently seen in cases of ESS than in cases of EC. Magnetic resonance imaging can play a role in both diagnosing ESS as well as in differentiating ESS from EC. Received: 17 December 1999 Revised: 18 May 2000 Accepted: 22 May 2000     

Hybrid RARE: Implementations for abdominal MR imaging

Hybrid RARE (rapid acquisition with relaxation enhancement) is a family of magnetic resonance (MR) imaging techniques whereby a set of images is phase encoded with more than one spin echo per excitation pulse. This increases the efficiency of obtaining T2-weighted images, allowing greater flexibility regarding acquisition time, resolution, signal-to-noise ratio, and tissue contrast. Hybrid RARE techniques involve several important new user-selectable parameters such as effective TE, echo train length, and echo spacing. Choices of other parameters, such as TR, sampling bandwidth, and acquisition matrix, may be different from those of comparable conventional T2-weighted spin-echo images. Different hybrid RARE implementations can be used for abdominal screening, with T2-weighted or T2-weighted and inversion-recovery contrast, or for characterizing liver lesions or imaging the biliary system with an extremely long TE. High-resolution images may be obtained by averaging multiple signals during quiet breathing, or images may be acquired more rapidly during suspended respiration. In this review, the authors discuss the basic principles of hybrid RARE techniques and how various imaging parameters can be manipulated to increase the quality and flexibility of abdominal T2-weighted MR imaging.     

Hepatic focal nodular hyperplasia: MR imaging at 1.0 and 1.5 T.

Ten cases of hepatic focal nodular hyperplasia (FNH) were studied with magnetic resonance (MR) imaging. Proof of diagnosis was by needle biopsy or follow-up of as long as 5 years. Both short TR/TE and long TR/TE images were obtained. The most common finding was isointensity of the lesion relative to liver parenchyma with all pulse sequences. A central scar was seen in only one patient and was hyperintense on long TR/TE images. Slight hyperintensity of the lesion on short TR/TE and long TR/TE images was seen in two cases. Textural heterogeneity was present in only one of these. The most common presentation in our series was a visually isointense lesion relative to liver on short TR/TE images and an isointense or slightly hyperintense lesion on long TR/TE images. A review of the literature and the present findings suggest that FNH has a variable appearance on MR images.     

Tubular ectasia of the rete testis: a potential pitfall in scrotal imaging

Tubular ectasia of the rete testis (TERT) is a benign entity due to dilation of the tubules of the rete testis. Most of the time it is discovered incidentally on scrotal sonograms and may be misinterpreted as malignant. This article outlines the diagnostic criteria of TERT, its possible causes, its incidence and its potential evolution. Recognizing this entity owing to its characteristic clinical, sonographic and, if necessary, MRI features is important to avoid unnecessary surgery or biopsies. Received: 4 August 1998; Revised: 15 April 1999; Accepted: 19 April 1999