Assessment of primary gynecologic malignancies: comparison of 0.15-T resistive MRI with CT

Clinical Value of Radioimmunoscintigraphy in the follow-up of Ovarian Carcinoma: A Prospective Study

Twenty-five patients treated with debulking surgery and chemotherapy for ovarian cancer were prospectively studied to evaluate the efficacy of radioimmunoscintigraphy (RIS) in detecting residual tumor before second-look surgery. RIS was performed with the monoclonal antibody OC125 F(ab')2 labelled with 1-131 without knowledge of clinical data and compared with subsequent surgical results. Second look showed tumor persistence in 12 patients, mostly characterized by small lesions. The overall diagnostic sensitivity of RIS was 50% and the specificity was 85%. In particular, RIS showed better sensitivity for pelvic tumor localizations than for abdominal sites (73% vs 33%); this was due to the inability of RIS to detect upper abdominal lesions. Therefore, our conclusion is that, at present, RIS cannot substitute surgical second-look in the management of ovarian cancer, however, considering that also ultrasonography, computer tomography and magnetic resonance are not always able to give definite diagnostic evidence in the follow-up of ovarian carcinoma, RIS could be added to these procedures to balance the limitations of each method. In this regard, the best application of RIS could be in the follow-up of patients with marker elevation without clinical evidence of disease, especially in the case of pelvic fibrosis or adhesions due to previous therapy, where the other non-invasive tools can give doubtful diagnostic results.

Diagnostic value of radiological tests in chronic pelvic pain

Chronic pelvic pain (CPP) presents a diagnostic as well as a therapeutic challenge to many clinicians. This chapter briefly describes the most frequent identifiable causes for CPP amenable to imaging; explains the most widely-used and widely available radiological tests for CPP; and compares/contrasts each test's utility and accuracy for a given causality. Examples of each imaging modality are included for demonstration purposes, and a summation table cross-references the best diagnostic methods with corresponding disease processes. References from the literature of both radiology and gynaecology were used in preparing this review.

Dynamic MR imaging of recurrent postoperative cervical cancer

The value of dynamic-contrast enhanced MR imaging using FLASH technique was studied in 13 patients with postoperative recurrent cervical cancer verified histopathology and in 9 patients without recurrence. Dynamic FLASH imaging and conventional spin-echo T1- and T2-weighted sequences were compared in a prospective fashion with regard to accuracy of the diagnosis of recurrent tumor using biopsy results as the gold standard. The contrast between the recurrent tumor and the surrounding pelvic tissues was also analyzed. The accuracy of depicting recurrent tumor or dynamic images (82%) was superior to that of pre- and postcontrast T1-weighted images and T2-weighted images (64%, 68%, and 64%, respectively). The contrast between the recurrent tumor and pelvic fat was greater on precontrast T1-weighted and dynamic images than on T2-weighted and postcontrast T1-weighted images. The dynamic images clearly showed involvement of the surrounding pelvic organs, because enhancement was observed exclusively in the tumor in the early dynamic phase. Accuracy regarding involvement of the urinary bladder or rectal wall on pre- and postcontrast T1-weighted images and T2-weighted images was lower than that on the dynamic images. Dynamic MR imaging has potential for use in the detection and evaluation of the extent of recurrent postoperative cervical cancer.

Magnetic resonance imaging of female pelvic masses and local recurrent tumors at an ultra low (0.02 T) magnetic field: correlation with computed tomography

Pelvic MR (41 patients) and CT (36 patients) examinations were performed on 14 females with a primary pelvic complaint, and on 28 females with a suspicion of local recurrent disease of gynecologic malignant tumor. Benign cystic tumors were found in eight patients, five patients had endometriomas, one had a lymphoma, and one had a small androblastoma. Ten local recurrent tumors were confirmed histopathologically or cytologically. All cysts, one endometrioma, the lymphoma, and six recurrent tumors were detected on images obtained by our ultra low field magnetic unit. The smallest cyst detected was 16 mm in diameter. Small scattered implants of endometriosis were not discerned. The appearance of the tumors did not differ essentially from those described at high magnetic fields. Physical examination detected all 10 recurrent tumors, CT detected 8 of them, and MRI 6 out of 9 cases. The sensitivities of physical examination, CT and MRI to find recurrent diseases were 100%, 80%, and 67%, respectively. Corresponding specificities were 93%, 67%, and 80%. The results indicate that physical examination is most important in recurrent diseases. CT is the basic method for imaging malignant pelvic tumors. MR imaging at 0.02 T magnetic field provides a convenient and inexpensive method for more specific information, if CT findings are equivocal. MRI at 0.02 T is also accurate in detecting benign pelvic masses, but the findings are not very specific.

Magnetic resonance imaging of the uterus at an ultra low (0.02 T) magnetic field

In vivo pelvic imaging of 39 women and in vitro relaxation time measurements of four uterine specimens were performed using an ultra low field (0.02 T) MRI unit. Average T1 times measured in vitro at 37 degrees C for the myometrium and endometrium were 206 ms (SD 47 ms) and 389 ms (SD 21 ms), respectively. Corresponding T2 times were 95 ms (SD 20 ms) and 167 ms (SD 13 ms). The proton relaxation of almost all myometrial specimens proved to be biexponential, but of all endometrial specimens was monoexponential. Contrast measurements between endometrium versus myometrium and myometrium versus the junctional zone were performed after imaging 18 volunteer women using different pulse sequence parameters. Normal uterine structures were optimally demonstrated by SE 700/70. Relatively short repetition times could be used, because spin-lattice relaxation times were short at the low magnetic field. Consequently, the short repetition times allowed averaging of four excitations to create adequate images within an acceptable scanning time. In addition to T2-weighted images a T1-weighted inversion recovery sequence with a short inversion time of 50 ms (IR 1000/50/40) adequately differentiated the three uterine zones. Although pathologic lesions of the uterus including leiomyomas, anomalies and carcinomas were well demonstrated, especially with the T2-weighted spin echo pulse sequence, further investigations are needed to evaluate the optimal technique for ultra low field MR imaging of uterine tumors.

Gynecologic magnetic resonance imaging

Magnetic resonance imaging (MRI) is an excellent modality with which to delineate normal anatomic structures and a variety of pathologic conditions in the female pelvis. It excels at demonstrating the extent of local tumor involvement in cases of endometrial and cervical cancer. It can help to elucidate the origin and nature of a variety of benign pelvic masses in cases where ultrasound findings are equivocal, and it is an accurate tool in demonstrating congenital abnormalities of the female reproductive tract. As technology continues to evolve, MRI will likely assume an even greater role in evaluating the female pelvis.

Staging of cervical carcinoma: accuracy of magnetic resonance imaging and computed tomography

A prospective study was undertaken to assess the ability of magnetic resonance imaging (MRI) to stage cervical carcinoma. Compared to computed tomography (CT), MRI showed a high degree of accuracy in correctly demonstrating involvement of the vagina, parametria and sidewalls, bladder, and lymph nodes but tended to overestimate disease in all of the categories studied. Large-scale studies comparing the two modalities are necessary because the most accurate staging of cervical carcinoma is crucial for selecting the best treatment protocols.

Magnetic resonance imaging in recurrent carcinoma of the cervix

Twenty patients with suspected recurrent cervical carcinoma were evaluated with computed tomography (CT) and high-field magnetic resonance imaging (MRI). Histological verification of the imaging findings were available in all cases. Computed tomography and MRI were equally effective in making the diagnosis of disease recurrence. The extent of vaginal recurrence and involvement of pelvic floor muscles was better shown on MRI than on CT.

Clinical and operative staging of cervical cancer

Clinical staging is inaccurate in about 50% of patients with cervical cancer. Most patients will be upstaged on the basis of surgical exploration, usually because of occult nodal metastases. Data from surgical staging indicate that the incidence of positive para-aortic nodes is about 7% for patients with Stage I disease, about 17% for Stage II, and 28% for Stage III. Extended field radiation, to the level of T12, can salvage about 25% of patients with positive para-aortic nodes. About 40% of patients having extended field radiation develop distant metastases, and about 25% develop a pelvic recurrence. These data suggest the need for prospective clinical trials to evaluate the role of chemoradiation for improved local control, prophylactic extended field radiation for improved regional control, and prophylactic chemotherapy for improved systemic control.

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.

Pitfalls in interpretation of computed tomography prior to second-look laparotomy in patients with ovarian cancer

Fifty-seven patients with ovarian cancer were assessed with computed tomography (CT) prior to undergoing second-look laparotomy. All patients were clinically free of disease following chemotherapy. Patients were scanned from the top of the liver to the symphysis pubis using oral, rectal and intravenous contrast medium. Tumour was correctly identified on CT scan in nine of 25 patients who had visible evidence of cancer at laparotomy. However, in the remaining 16 patients peritoneal studding was present and was not detected. Tumours smaller than 1.5 cm in size were not found by CT scanning. Computed tomography showed abnormality in eight of 32 patients subsequently found to be free of disease. Fine-needle aspiration cytology, bolus contrast injection and repeat scanning with additional oral contrast medium could have assisted in these circumstances. As persistent disease is by definition, a contraindication to second-look laparotomy, aggressive pre-operative assessment will spare some patients unnecessary surgery. However, CT cannot detect the small nodules often present in ovarian cancer, and thus, normal scans cannot replace surgical restaging.

Magnetic resonance imaging of gynecologic masses

The pelvis of 21 women with various gynecological masses were imaged with magnetic resonance (MR) imagers at 2.0 and 0.5 T. Fifteen normal individuals were used for studying the normal appearance of the female genitalia using spin echo pulse sequences with various pulse repetition (TR) and spin echo (TE) time values. Images were compared with those of the ultrasonic images, intraoperative findings, and the histopathologic examinations. The masses included simple ovarian cyst, cystadenoma, serous cystadenocarcinoma, ovarian teratoma, dysgerminoma, and uterine myoma. MR imaging was useful in demonstrating the anatomy and pathology of the cases examined in this study. It detected the internal structure of some tumors which were sonographically homogeneous. The potential of MR in staging of malignancies was demonstrated.

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.

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.

MRI of the pelvis in comparison with CT scan

This study gives results of magnetic resonance imaging (MRI) in the evaluation of male (23 cases) and female (29 cases) pelvis. Thirty nine patients with abnormal pelvis were compared with CT and ultrasounds. MRI and CT have proven equally sensitive to the presence of disease, with a better visualization of calcified tumours or benign lesions with CT, and a superior display of soft tissue spreads and bone metastases with MRI. The signal characteristics from various uterine, bladder and ovarian tumours show an overlap. The same phenomenon is observed between benign and malignant prostatic hypertrophy. The best sequences for pelvic study are, in our experience, IR or short TR spin-echo for T1-weighted images, and spin-echo with 1200 TR for T2 images. Calculated T1 and T2 maps may improve MRI results.

Present clinical status of magnetic resonance imaging

Magnetic resonance imaging has achieved clinical importance and has become the primary tool in the investigation of head, spinal cord, pelvis, cancellous bone, pericardium (with gating), gallbladder, lymph node masses, and very soon, in the evaluation of joints. In many areas, particularly with respiratory and ECG gating, this method promises to replace all other imaging modalities with the precision of information obtained. Today the exceptions are the alimentary tube and its mesentery, between the esophagus and rectum, and the peripheral lung.