Magnetic resonance imaging--its application to cervical carcinoma

Magnetic resonance imaging of uterine malignancies

Magnetic Resonance Imaging (MRI) is the criterion standard in the assessment and staging of uterine cancer because of the high tissue contrast between glandular lining and inner and outer muscle layers of the uterine corpus and cervix on T2-weighted scans. It is also an essential tool in monitoring treatment response and in assessing disease recurrence in these patients. The key to a successful examination lies in good patient preparation, use of antiperistaltic agents, and a meticulous scanning technique. Endometrial carcinomas are the most common uterine malignancy, occurring in a primarily postmenopausal population. Dynamic contrast-enhanced scans may be required in addition to T2-weighted images to assess the presence of myometrial invasion in this age group. Cervical cancers occur in a younger population and are readily assessed with T2-weighted imaging. Use of an endovaginal receiver coil allows high spatial resolution imaging of the cervix, which is particularly useful when assessing patients for fertility-sparing procedures such as trachelectomy. Uterine sarcomas are 1% to 3% of all uterine malignancies and usually arise from a mixture of homologous and heterologous elements. Rarely, lymphoma, small cell carcinoma and metastatic deposits involve the uterus. This review summarizes the optimal scanning techniques for demonstrating uterine malignancy and discusses the role of imaging and the MRI appearances of uterine tumors.

Use of transvaginal sonography in the evaluation of endometrial hyperplasia and carcinoma

Published studies relating to the use of transvaginal sonography (TVS) in the evaluation of endometrial hyperplasia and carcinoma were reviewed. Approximately 80 percent of all curettage procedures performed for postmenopausal bleeding result in benign diagnoses, therefore, if a noninvasive modality such as TVS can be accurately used to determine endometrial thickness measurements below which pathology is less likely, sampling may be avoided. The largest study evaluating endometrial measurements in postmenopausal women with bleeding, known as the Nordic trial, found that for a cut-off value of < or = 4 mm, 96 percent sensitivity and 68 percent specificity was achieved. Another study evaluated endometrial echomorphology in addition to measurement and found that the combined approach improved the predictability of pathologic findings. TVS may also be used to assess the depth of myometrial invasion in patients already diagnosed histologically with endometrial carcinoma. Although MRI is considered the established tool in the presurgical evaluation of the patient with carcinoma, TVS was found to perform only slightly less accurately than MRI. The published studies regarding TVS and/or MRI are reviewed. Finally, the use of TVS in conjunction with a new modality, sonohysterography, in the evaluation of patients on tamoxifen therapy, is discussed. Although the published cut-off values for endometrial thickness measurements do not apply to this group of patients, a procedure whereby sterile saline is injected into the uterine cavity, via a thin catheter, provides additional information regarding endometrial contours. Once the procedure is performed, the supposed complex endometrial echo seen on TVS is often found to actually be located in the subendometrial myometrium and the endometrium itself is thin and regular. The role for TVS is well established in the search for endometrial hyperplasia and carcinoma, as well as evaluating the presence of myometrial invasion once the diagnosis is made.

Role of transabdominal pelvic ultrasound and computed tomography in the detection of bladder involvement in advanced cancer of the cervix

The imaging data of 125 advanced cancer cervix patients attending the Institute Rotary Cancer Hospital between June 1992 and June 1994 was reviewed. The aim of the study was to assess the role of transabdominal pelvic ultrasound (TAPUS) and computed tomography (CT) in the detection of bladder involvement. TAPUS was performed in 65 patients (group I) and CT in 60 patients (group II). With respect to clinical stage, both groups were comparable. Cystoscopy was performed in all patients and the findings were taken as the gold standard for comparison of imaging data. The sensitivity, specificity and accuracy of TAPUS were 65, 94 and 75%, respectively, while those for CT were 80, 92 and 85%, respectively. Results of the present study reveal that the accuracy of TAPUS is comparable to the accuracy of other imaging modalities in the detection of bladder involvement in cervical cancer and that it should be used more frequently in developing countries that deal with a large number of cervical cancer patients in view of its easy availability, low cost and absence of exposure to radiation.

Diagnostic imaging of gynecological diseases: the clinician's view

The introduction of ultrasonography, computerized tomography, and magnetic resonance imaging has led to tremendous progress in the diagnostic evaluation of gynecologic diseases. Refinements in these techniques have allowed the gynecologist to diagnose unsuspected pathology, define disease and its extent, and select the most appropriate treatment despite limitations in specificity experience and cost. Practically the most appropriate imaging modalities are: ultrasonography for adnexal masses, computerized tomography for advanced cervical cancers, and magnetic resonance imaging for corpus cancers and selected cervical cancers.

Quantitative magnetic resonance imaging in cervical carcinoma: a report on 30 cases

T1 and T2 relaxation times were calculated, before radiation therapy, in 30 patients with cervical carcinoma. Eight healthy young women were submitted to magnetic resonance imaging (MRI) to determine T1 and T2 times of the normal cervix. Magnetic resonance imaging was repeated, in 22 patients, during radiation therapy and at follow-up. During treatment and follow-up, patients with complete tumour response showed a significant T1 reduction compared with the pre-treatment values. With persistence of palpable or visible tumour, T1 times showed a small decrease during therapy, and a marked increase at subsequent examinations. The results suggest that the modifications of T1 times, during radiation therapy and follow-up, could be considered as a useful discriminant between patients with differing tumour response.

Magnetic resonance imaging, computed tomography and endosonography in the local staging of carcinoma of the cervix

Thirty-seven patients with carcinoma of the cervix were prospectively staged by examination under anaesthesia (EUA), transvaginal and transrectal ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). Pathological correlation was available for 20 patients. In the pathologically staged patients, EUA agreed with the staging in 17, understaging three patients. Endosonography agreed with the staging in 19, CT in 16 and MRI in 18 patients. For the remaining 17 patients, endosonography agreed with the EUA findings in 13, CT in 12 and MRI in 12. This study has shown that endosonography and MRI are more accurate than CT in the local staging of carcinoma of the cervix. Computed tomography was least accurate in staging early tumours and differentiating between Stage Ib and IIb disease. Lymph node involvement was detected with equal frequency by both CT and MRI. Magnetic resonance imaging was useful in identifying vaginal and bladder wall involvement and in one patient showed features due to an unsuspected early pregnancy.

Staging of carcinoma of the uterine cervix: MRI-surgical correlation

Forty-six patients with carcinoma of the uterine cervix were examined with spin-echo magnetic resonance imaging (MRI) using a superconducting magnet operating at a field strength of 0.5 T. All subjects later underwent lymphadenectomy and, when appropriate, radical hysterectomy. Surgical-pathologic correlation was carried out in order to assess the accuracy of the imaging modality in the staging of the disease. In the detection of nodal involvement, the accuracy of MR was 76%. The accuracy in determination of tumour size approached 100%. In the assessment of parametrial and vaginal involvement, the accuracy was 85% and 100% respectively.

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.