Magnetic resonance imaging of benign ovarian masses

Forty-one patients with 45 pelvic mass lesions were assessed by magnetic resonance imaging (MRI). All lesions were initially considered to be benign ovarian masses with this diagnosis confirmed in 36 lesions. The characteristics on MRI are analysed and features useful in predicting histological type identified. Our results indicate that a high, though not absolute, level of diagnostic specificity should be obtainable in identification of ovarian pathology.     

Advances in magnetic resonance imaging of the pelvis at 0.15 tesla

The recent development of improved commercial radiofrequency coils and multiecho, multislice software for low field strength magnetic resonance systems has markedly increased the clinical utility of magnetic resonance imaging (MRI) of the pelvis at low field strengths. An evaluation of 70 patients with a variety of pelvic lesions and 14 normal volunteers who were studied using 0.15 T resistive magnet scanner revealed that anatomic structures and a variety of mass lesions could be clearly depicted in transaxial, sagittal and coronal planes using this updated system. Accurate characterization of lesions was possible in many instances using T2 weighted multiecho scans with echo time (TE) ranging from 30 ms to 120 ms (45 ms-180 ms using a reduced bandwidth technique). T1 weighted multislice scans demonstrated anatomic structures to best advantage and calculation of T1 and T2 relaxation times frequently facilitated more accurate differential diagnosis, particularly in the case of ovarian lesions.     

Magnetic resonance imaging of the pelvis

Magnetic resonance imaging (MRI) is a very promising modality for evaluation of the pelvis. Its major role appears likely to be the staging of known malignancies. In this article, the appearance of normal pelvic anatomy on MR scans is presented, as well as a discussion of the use of MRI in the detection and evaluation of pathologic conditions and a comparison of MRI with CT.     

Magnetic resonance imaging of the female pelvis

Magnetic resonance (MR) imaging is particularly well suited for the evaluation of the female pelvis because of the lack of respiratory motion and the multiplanar imaging ability of MR. The MR appearance of normal anatomy is dependent on the pulse sequence used. This is also true for pelvic pathology. Primary cervical carcinoma is best seen on T2-weighted images; parametrial extension and lymph node metastases are best evaluated on T1-weighted images. Endometrial carcinoma is also best seen on T2-weighted images. Absence of the junctional low intensity band of the uterus may indicate myometrial invasion by endometrial tumor, although more data are needed to make a final diagnosis. Uterine leiomyomata have a variable MR appearance which may be related to the degree of cellularity of the tumor. Our experience in the MR appearance of adnexal masses is limited. MR imaging should assume a more important role in imaging the female pelvis in the future.     

Magnetic resonance imaging of the female pelvis

Magnetic resonance (MR) imaging is particularly well suited for the evaluation of the female pelvis because of the lack of respiratory motion and the multiplanar imaging ability of MR. The MR appearance of normal anatomy is dependent on the pulse sequence used. This is also true for pelvic pathology. Primary cervical carcinoma is best seen on T2-weighted images; parametrial extension and lymph node metastases are best evaluated on T1-weighted images. Endometrial carcinoma is also best seen on T2-weighted images. Absence of the junctional low intensity band of the uterus may indicate myometrial invasion by endometrial tumor, although more data are needed to make a final diagnosis. Uterine leiomyomata have a variable MR appearance which may be related to the degree of cellularity of the tumor. Our experience in the MR appearance of adnexal masses is limited. MR imaging should assume a more important role in imaging the female pelvis in the future.     

Magnetic resonance imaging of renal masses at 0.02 tesla

To determine the usefulness of extremely low field magnetic resonance imaging (MRI) in the evaluation of renal masses 19 patients with 15 tumors (13 renal and 2 renal pelvic carcinomas) and 8 cysts were examined in a 0.02 tesla MRI unit. The findings were compared with results of computed tomography (CT) and ultrasound. Cavography was performed in 6 patients. MRI enabled differentiation between cysts and solid tumors. Tumor extension into the inferior vena cava could be demonstrated in one case and liver metastases in two patients. The image quality was inferior to that reported at higher field strengths and the tumors were more precisely staged by CT and ultrasound. At present, it is unlikely that low field MRI will play any substantial role in the evaluation of renal masses.     

Magnetic resonance imaging of the pediatric pelvis.

The increased use of MR imaging in the pediatric population is due to the lack of ionizing radiation, multiplanar imaging capability, and excellent tissue contrast differentiation. MR imaging is most commonly indicated in the evaluation of tumors to provide information about resectability and extent of lesions. It is also useful in the evaluation of congenital anomalies of the pelvic organs. This is a rapidly changing field; the development of fast-scanning techniques and contrast agents for the bowel should further improve the utilization of MR imaging in pediatrics.     

Magnetic resonance imaging of the abnormal female pelvis

Twenty-three women with 27 instances of pelvic pathology were evaluated by magnetic resonance imaging (MRI). Different pulse sequences were used, which varied the dependence of the images on T1 and T2. Sonography was performed on 22 of the 23 patients. Five patients had CT examinations, including the patient who did not have sonography. MRI was also done in four normal volunteers. The spatial resolution of the MRI scans with short TR and TE intervals approached that of CT. There was overlap of MRI signal characteristics between various pathologic entities and also within the same entity (e.g., cystadenomas and endometriomas).     

Magnetic resonance imaging of the pelvis. Methodological aspects

Multiparametric choice is needed in Magnetic Resonance Imaging (MRI). In addition to matrix definition, section thickness, accumulation number, the repetition time TR, the echo time TE (for the spin echo technique) and the plane selection are of great importance. In pelvic examination, information supplied by T1 and by T2 weighted images is complementary. So, comparison between the three dimensional sections is of great interest. Although long acquisition times could, in theory, provide better images and therefore more clinical information, the patient comfort must be considered in choosing a reasonable examination time. We believe that it is possible, without great loss of information, not to make inversion recovery sequences. Using a 0.5 T superconducting magnet, sequences were done with TR of 1,200 ms for T2 weighted images and two echoes with TE of 40 or 50 ms. Twice repeated sequences (for averaging purpose) and 256(2) matrix (with a 42 cm field diameter) seem to be well adapted to MRI clinical applications.     

Magnetic resonance imaging of the normal female pelvis.

MR imaging has emerged as an important modality in the evaluation of the female pelvis as a result of the detailed demonstration of normal anatomy. Tissue planes within the uterus, cervix, vagina, and ovaries are clearly delineated, thus enabling a better understanding of normal anatomy and, therefore, pathology.     

Magnetic resonance imaging of the pelvis: prostate and urinary bladder

Magnetic resonance imaging has opened up a new horizon in the evaluation of the male pelvis. Its direct multiplanar imaging and display of the unique tissue contrast allows for the demonstration of prostate anatomy. Prostatic disease, even when confined to the gland, is easily depicted. However, one cannot distinguish benign from malignant processes. In a patient with a known prostatic neoplasm, magnetic resonance is useful as a staging modality. Accuracy in the staging of prostatic malignancies by MRI surpasses that of ultrasound or CT. In the evaluation of the urinary bladder, the greatest advantage of magnetic resonance is its ability to differentiate between a normal bladder, and other pathologic conditions affecting the bladder, including inflammatory, congestive and neoplastic processes. In the evaluation of bladder carcinoma, magnetic resonance is useful as a staging modality. Clinical application of magnetic resonance is just beginning and therefore, the full potential of the modality has yet to be explored.     

Magnetic resonance imaging of the pelvis: Prostate and urinary bladder

Magnetic resonance imaging has opened up a new horizon in the evaluation of the male pelvis. Its direct multiplanar imaging and display of the unique tissue contrast allows for the demonstration of prostate anatomy. Prostatic disease, even when confined to the gland, is easily depicted. However, one cannot distinguish benign from malignant processes. In a patient with a known prostatic neoplasm, magnetic resonance is useful as a staging modality. Accuracy in the staging of prostatic malignancies by MRI surpasses that of ultrasound or CT. In the evaluation of the urinary bladder, the greatest advantage of magnetic resonance is its ability to differentiate between a normal bladder, and other pathologic conditions affecting the bladder, including inflammatory, congestive and neoplastic processes. In the evaluation of bladder carcinoma, magnetic resonance is useful as a staging modality. Clinical application of magnetic resonance is just beginning and therefore, the full potential of the modality has yet to be explored.     

Magnetic resonance imaging of the female bony pelvis: MRI pelvimetry

Magnetic resonance imaging (MRI) was used for the evaluation of the bony pelvis in 4 pregnant and 10 non-pregnant women. The anatomical details and shape of the bony pelvis were easily examined and the main pelvic measurements were estimated on the sections and programs. The end points were easily demonstrated. There was no need to correct for magnification. The study confirmed that MRI is a very valuable technique for assessment of the pelvis. Although it is expensive, it overcomes the technical difficulty of the other methods used for pelvimetry.     

Magnetic resonance in the evaluation of mediastinal masses

Thirty-three patients with mediastinal masses were examined by means of MRI to obtain elements for lesion characterization, to evaluate lesion extent, and to assess the relationship of the mass to the surrounding structures, especially the great vessels (accuracy: 84.84%), mediastinal structures (accuracy: 76.78%), and lung parenchyma (accuracy 69.69%). MR data were compared to CT findings; sensitivity, specificity and accuracy were subsequently compared to surgical and histologic findings. The results have shown MRI to be a very reliable method in the evaluation of mediastinal masses.     

Magnetic resonance imaging of the normal prostate at 1.5 T

Prostatic magnetic resonance images of 22 male volunteers less than 30 years old and with no known genito-urinary tract disease were obtained at 1.5 T. Normal anatomical features of the prostate were studied with spin-echo techniques. Different zones of the normal gland are shown by T2-weighted images: the anterior fibromuscular fascia, the central prostate, the peripheral prostate and the periurethral zone can be differentiated. The normal prostate gland is shown on T1-weighted images as a homogeneous appearance. It is important to recognize the normal zonal anatomy of the prostate since prostatic disorders arise in different anatomical zones.