Computed tomography versus magnetic resonance imaging for the evaluation of suspected pituitary adenomas

The purpose of this study was to evaluate and compare thin-section magnetic resonance imaging (MRI) and high-resolution computed tomography (CT) in patients with suspected pituitary adenomas. Twenty-two patients (19 women and three men) with hyperprolactinemia (N = 16), increased growth hormone secretion (N = 2), increased corticotropin secretion (N = 1), and nonsecreting adenomas (N = 3) were studied with both contrast-enhanced, high-resolution CT scanning and thin-section MRI. Contrast-enhanced examinations consisted of contiguous 1.5-mm coronal sections during contrast infusion. The MRI examinations consisted of spin-echo T1- and T2-weighted sequences with a 2.5-3.0-mm slice thickness on the coronal and sagittal planes. Fourteen women had similar findings on CT and MRI (four macroadenomas, six microadenomas, one wide stalk, two empty sellas, and one normal study). The remaining eight subjects had conflicting results: CT findings were compatible with a microadenoma in all eight patients, whereas MRI detected one enlarged pituitary, two empty sellas (one with prolapse of the optic chiasm) without evidence of adenoma, and five normal examinations. Thus, both studies detected macroadenomas accurately, but CT was frequently unable to diagnose correctly an empty sella. Because patients with possible microadenomas were not submitted to surgery, the accuracy of either radiologic method cannot be assessed at this time. However, we suggest that MRI is superior to CT because of its inherently greater soft-tissue contrast, which allows clear visualization of the optic chiasm, optic nerves, cavernous sinuses, and carotid arteries.     

Fetal magnetic resonance imaging.

Fast magnetic resonance imaging (MRI) has revolutionized our ability to image the fetus. Using fast scanning techniques, individual images are obtained in 300-400 ms, allowing for imaging of the fetus without sedation. MRI is most useful for evaluation of the anomalous fetal central nervous system, for further characterization of complex anomalies not fully elucidated by ultrasound and for evaluation of patients desiring fetal surgery. This review describes the history of fetal MRI, discusses current applications and mentions developments on the horizon.     

Correlation between clinical, endocrinologic and nuclear magnetic resonance findings in women with suspected pituitary adenomas

Twenty-nine women with suspected pituitary adenomas were evaluated with nuclear magnetic resonance (NMR). Twenty-six had prolactin levels less than 100 ng/mL, and three had levels greater than 100. We tried to correlate the clinical findings with the prolactin levels and NMR findings. Pituitary adenomas were detected on NMR even with prolactin levels less than 100 ng/mL.     

The integration of computed tomography and magnetic resonance imaging in treatment planning for gynecologic cancer.

Both CT and MRI may play an important role in the initial assessment and subsequent management of patients with gynecologic cancer. The different capabilities of these examinations make the choice of test dependent on what portion of the body is visualized (e.g., chest, upper abdomen, or pelvis) and what information is sought. Body imaging can be scheduled appropriately when the findings from the study will have a significant impact on patient management (e.g., operative versus nonoperative management, selection of treating physician, and initial modality of treatment). However, the limitations of each modality must be appreciated. In general, a negative CT or MRI will not exclude the possibility of small volume disease involvement, and a critical positive study should, when practical, be histologically confirmed. Neither test stands alone, but each plays a role when integrated with careful clinical history, physical examination, and other laboratory and radiologic examinations.     

Progression of a giant omphalocele in utero: ultrasound and fetal magnetic resonance imaging findings

A 34-year-old Hispanic woman was referred to us at 18 weeks' gestation for prenatal ultrasound. Sonographic evaluation showed a large omphalocele similar in size to the abdomen. Ultrasonographic and MRI images illustrating the typical appearance of a giant omphalocele are provided.     

A case of primary uterine angiosarcoma: magnetic resonance imaging and computed tomography findings

Primary uterine angiosarcoma is exceedingly rare and has a poor prognosis. Moreover, the radiologic findings of this disease have not been previously documented. We present a case of a 62-year-old woman with primary uterine angiosarcoma who underwent abdominal hysterectomy and bilateral salpingo-oophorectomy. Histologically, interlacing vascular spaces were lined by endothelial cells showing nuclear pleomorphism and mitotic activity. Immunohistochemical staining was positive for the endothelial cell markers CD31, CD34, and Factor VIII, supporting the diagnosis of primary uterine angiosarcoma. Magnetic resonance imaging (MRI) revealed a heterogeneous mass with high and low signal intensity (T2 weighted) in the uterus and an intense contrast-enhanced anterior area within the mass (gadolinium enhanced, T1 weighted). The lesion was also enhanced on computed tomography (CT). Radiologically, the most helpful sign in the characterization of uterine angiosarcoma is marked heterogeneity on T2-weighted MRI with focal areas of high signal intensity, known as the "cauliflower-like appearance." In addition, findings of a strongly enhanced lesion on gadolinium-enhanced T1-weighted MRI and contrast-enhanced CT also support the diagnosis of angiosarcoma.     

Fetal magnetic resonance imaging

PURPOSE OF REVIEW: Fetal magnetic resonance imaging is becoming more used in the evaluation of complex fetal abnormalities. Rapid advances in the technology and application of fetal magnetic resonance imaging necessitate a review of this subject. RECENT FINDINGS: Diffusion-weighted imaging, magnetic resonance spectroscopy and functional magnetic resonance imaging may allow assessment of fetal brain even before anatomical abnormalities are demonstrated. We discuss the uses of fetal magnetic resonance imaging in better assessment of pulmonary hypoplasia, congenital diaphragmatic hernia and renal anomalies. SUMMARY: The additional information from fetal magnetic resonance imaging, beyond that obtained by ultrasound, is invaluable in prenatal counseling, delivery planning and planning for pre- or postnatal intervention. As intrauterine and neonatal surgery evolve, so will the utilization of fetal magnetic resonance imaging.     

Fast-scan magnetic resonance imaging of fetal anomalies.

OBJECTIVE--To identify those congenital fetal anomalies, previously identified by ultrasound scanning, in which fast-scan magnetic resonance imaging (F-SMRI) would give additional information for the perinatal management of the infants. DESIGN--Observational clinical study. SETTING--Hospital Department of Obstetrics and Gynaecology/Resonance Research Centre. SUBJECTS--Seven women carrying eight fetuses in whom congenital abnormalities had been identified using ultrasound scans. The duration of the pregnancies was 28 to 39 weeks gestation. INTERVENTIONS--Fast-scan magnetic resonance imaging at between 28 and 39 weeks gestation. MAIN OUTCOME MEASURES--Identification of fetal abnormalities. RESULTS AND CONCLUSIONS--F-SMRI was of limited value in the diagnosis of further assessment of fetuses with abnormalities of accumulation of tissue fluid. Renal anomalies were poorly identified unless associated with cystic formation of the kidney. Further study is required in the imaging of fetal central nervous system anomalies. Until echoplanar imaging is more widely available, MRI does not contribute to the diagnosis of cardiac anomalies. F-SMRI appears to be most useful in the diagnosis and management of soft tissue gastro intestinal abnormalities.     

Abdomino-pelvic leiomyoma of the round ligament: contribution of computed tomography and magnetic resonance imaging

A case of bulky abdomino-pelvic leiomyoma of the round ligament is reported with the CT (computed tomography) and MRI (magnetic resonance imaging) findings. Leiomyoma appeared as encapsulated heterogeneous tumor on the spontaneous contrast CT images and on post-gadolinium contrast MRI. Lack of specificity hinders diagnosis before surgery. Leiomyoma of the round ligament is the most frequent histological type among round ligament tumors. Leiomyoma of the round ligament must be retained as a possible etiology of inguinal mass or pelvic tumor.     

Prenatal imaging: ultrasonography and magnetic resonance imaging

The Eunice Kennedy Shriver National Institute of Child Health and Human Development held a workshop on September 18-19, 2006, to summarize the available evidence on the role and performance of current fetal imaging technology and to establish a research agenda. Ultrasonography is the imaging modality of choice for pregnancy evaluation due to its relatively low cost, real-time capability, safety, and operator comfort and experience. First-trimester ultrasonography extends the available window for fetal observation and raises the possibility of performing an early anatomic survey. Three-dimensional ultrasonography has the potential to expand the clinical application of ultrasonography by permitting local acquisition of volumes and remote review and interpretation at specialized centers. New advances allow performance of fetal magnetic resonance imaging (MRI) without maternal or fetal sedation, with improved characterization and prediction of prognosis of certain fetal central nervous system anomalies such as ventriculomegaly when compared with ultrasonography. Fewer data exist on the usefulness of fetal MRI for non-central nervous system anomalies.     

Abdominal wall characterization with magnetic resonance imaging and computed tomography. The effect of obesity on the laparoscopic approach.

Laparoscopic complications are most often related to insertion of the Veress cannula or primary trocar. We evaluated the midline abdominal walls of 33 women using magnetic resonance imaging (MRI) or computed tomography to determine if the location and angle of placement of the Veress cannula and primary trocar should be chosen according to the patient's weight to minimize the risk of both preperitoneal placement and retroperitoneal vessel injury. The anterior abdominal wall thickness was measured for three standard approaches used for placement of laparoscopic instruments through the umbilicus at both 45 degrees and 90 degrees from the horizontal. In addition, the distance from the base of the umbilicus to the retroperitoneal vessels was measured. We found that in the nonobese patient, both the Veress cannula and primary trocar can be inserted at 45 degrees, at either the lower margin or base of the umbilicus, with little risk of preperitoneal placement or major vessel injury. In the overweight patient the cannula and trocar can still be inserted at 45 degrees, but placement through the base of the umbilicus rather than the lower margin will minimize the chance of preperitoneal placement. In the majority of obese patients it is only by placing both the Veress cannula and sharp trocar through the base of the umbilicus at or near 90 degrees that preperitoneal placement can be avoided. Alternatively, an open laparoscopic technique can be considered in such high-risk patients to decrease the risk of major vessel injury.     

Staging of cervical cancer: comparison between magnetic resonance imaging, computed tomography and pelvic examination under anesthesia.

A prospective study was undertaken to compare magnetic resonance imaging (MRI) with computed tomography (CT) and examination under anesthesia (EUA) in staging cervical carcinoma, with special emphasis on parametrial status. Twenty patients with carcinoma of the cervix, in whom the extent of the disease was surgically confirmed, were analyzed by MRI, CT and EUA. The tumor size estimated by MRI correlated well (r = 0.79, p < 0.001) with those obtained by histopathologic measurement of the surgical specimen. Neither clinical examination nor CT could precisely estimate tumor size. The overall accuracy rate of MRI in staging carcinoma of the cervix was 75%, compared with 32% for CT staging and 55% for clinical staging. The accuracy rate of these modalities for parametrial status was 90% for MRI, 55% for CT and 82.5% for EUA. MRI accurately excluded all 20 patients with pelvic side wall, bladder and rectal involvement. In conclusion, MRI is superior to CT and EUA in assessment of the parametrium (90% vs 55% vs 82.5%, p < 0.005). From MRI, tumor size can be estimated precisely. Although a larger scale study comparing MRI and CT is needed to determine their roles, both should help in the diagnosis and selection of proper treatment for cervical carcinoma. Our preliminary report agrees with previous reports that MRI is promising and indispensable. MRI should be routinely used in conjunction with clinical staging to determine appropriate therapy in patients with cervical carcinoma.     

Classification of asymptomatic adnexal masses by ultrasound, magnetic resonance imaging, and positron emission tomography

OBJECTIVE: The purpose of this study was to determine the diagnostic accuracy of sonography versus magnetic resonance imaging (MRI) and positron emission tomography (PET) in the characterization of adnexal masses. METHODS: One hundred and one patients with asymptomatic adnexal masses, which were scheduled for laparoscopy, underwent preoperative transvaginal ultrasound, MRI, and 2-[(18)F]fluoro-2-deoxy-d-glucose PET. Two different sonomorphological scoring systems were used to distinguish malignant from benign lesions. In addition, transvaginal Doppler flow velocimetry was performed and the resistance index (RI) of ovarian blood vessels was calculated. RI values below 0.45 were considered to indicate malignancy. MRI was evaluated on the basis of signal intensity and morphologic features such as wall thickness, septations, fluid or solid components, and vascularity. PET imaging was used to determine 2-[(18)F]fluoro-2-deoxy-D-glucose uptake. Malignancy was suspected if radiotracer uptake equaled or exceeded that of the liver. Based on histologic findings, sensitivity, specificity, positive and negative predictive values, and accuracy were first calculated independently for each imaging technique. Finally, a second session resulted in a consensus diagnosis being made based on the findings of all three modalities. RESULTS: Sonographic evaluation of adnexal masses resulted in correct classification of 11 of 12 ovarian malignancies (sensitivity 92%) but with a specificity of only 60%. With MRI and PET, specificities improved to 84 and 80% respectively, but sensitivities decreased. When all imaging modalities were combined, sensitivity and specificity were 92 and 85%, respectively, and accuracy was 86%. CONCLUSION: Combination of ultrasound with MRI and PET may improve accuracy in differentiation of benign from malignant ovarian lesions. However, negative MRI or PET results do not rule out early-stage ovarian cancer or borderline malignancies.