Magnetic resonance imaging in the preoperative assessment of clinical stage I endometrial carcinoma

Magnetic resonance (MR) imaging may aid in preoperative treatment planning of endometrial carcinoma by accurately estimating tumor volume, depth of myometrial invasion, and extrauterine extension. Preoperative MR scans were obtained on 24 women with clinical stage I endometrial cancer. MR scans were evaluated for uterine size, as an indirect measure of tumor volume, and depth of myometrial invasion. MR detected deep invasion (greater than or equal to 50% of myometrial thickness) with a sensitivity of 71% and specificity of 83% (accuracy 79%) when compared with the pathologic findings. MR staging may assist in deciding which patients should have lymph node dissection at surgery and may aid in decisions regarding adjunctive radiation therapy.     

Myometrial invasion by endometrial carcinoma: assessment by MR imaging.

In patients with early-stage endometrial cancer, preoperative knowledge of myometrial tumor extension has important prognostic and therapeutic implications. The purpose of this prospective study was to determine the sensitivity and specificity of MR imaging for assessing the depth of myometrial invasion in patients with endometrial cancer that clinically was thought to be confined to the uterine corpus. Sixty-five consecutive patients were included in the study. All patients had MR imaging before radical surgery. MR imaging findings were compared with microscopic pathologic findings in all cases. On MR images and at histologic analysis, myometrial invasion was classified as absent (tumor confined to the endometrium), superficial (less than 50% of myometrial thickness), or deep (50% or more of myometrial thickness). At histologic examination, tumor limited to the endometrium was proved in 14 cases, superficial myometrial invasion by tumor was present in 34 cases, and deep tumor invasion was demonstrated in 17 cases. In determining the presence of tumor confined to the endometrium, MR imaging had a sensitivity of 57% and a specificity of 96%. In the assessment of tumor with superficial myometrial invasion, MR imaging had a sensitivity and a specificity of 74%, whereas in assessing deep myometrial penetration, the sensitivity and specificity of MR were 88% and 85%, respectively. Errors in MR interpretation when determining myometrial tumor spread were more frequently overestimations rather than underestimations. Our results indicate that MR imaging is useful for the preoperative assessment of myometrial invasion in patients with proved endometrial cancer.     

Cancer of the endometrium: value of MR imaging in determining depth of invasion into the myometrium

The depth of invasion into the myometrium correlates with the frequency of lymph node metastases in patients with cancer of the endometrium. A distinction between superficial invasion (less than 50% of the thickness of the myometrium) and deep invasion (greater than 50%) is particularly important. The ability to distinguish between these two groups on MR was studied in 33 patients with endometrial cancer who had primary hysterectomy. The overall accuracy of MR in showing deep invasion was 82%, with a sensitivity of 91% and a specificity of 64%. The main limitation of MR was four false-positive results with regard to deep invasion. In all of these, the erroneous diagnosis was found at histologic examination to be due to a large polypoid tumor that distended the uterus so that a thin rim of myometrium was stretched over it rather than being deeply infiltrated by it. Our experience shows that MR can be used to distinguish between superficial and deep invasion of the myometrium. However, degree of invasiveness may be overestimated in exophytic polypoid tumors with significant intraluminal extension.     

Staging in local endometrial carcinoma. Assessment of magnetic resonance and ultrasound examinations

Possible deep (more than an inner third of the uterine wall) myometrial invasion and cervical extension of endometrial carcinoma were evaluated prospectively using magnetic resonance (MR) and transabdominal real-time sonography (US) in 20 and 10 patients, respectively. The data obtained from these examinations were compared with hysterosalpingography (HSG) and clinical modalities including hysteroscopy, sounding and histopathologic findings after surgery. The concordance of outlining cervical extension was between MR and hysteroscopy 85 per cent, and between US and hysteroscopy 50 per cent. Deep myometrial tumor invasion was suggested in 4/10 patients by US and in 6/20 by MR, and was confirmed in all but one in each group at histologic examination of the resected uterus. There were no false negative US or MR examinations. Transabdominal US did not prove accurate in defining local endometrial carcinoma (distinguishing between stages I and II), but it may be used as an additional tool in revealing myometrial invasion. MR, however, seems to refine the delineation of uterine tumor growth.     

MR imaging of bladder neoplasms: Correlation with pathologic staging

This retrospective study describes the accuracy of magnetic resonance (MR) imaging in determination of local disease extent in 34 examinations performed for evaluation of primary or recurrent bladder carcinoma. The 34 examinations were carried out in 29 patients (17 men, 12 women, aged 34-89 years). All studies were followed within 30 days by surgical and pathologic evaluation. Images were interpreted by two radiologists unaware of clinical or pathologic findings. MR imaging staging conformed to the TNM system of the International Union Against Cancer (IUAC). Pathologic evaluation showed bladder neoplasms in all cases; three patients' pathologic specimens contained two or more histologic types of tumors. MR imaging staging of the depth of tumor invasion was correct in 85% of examinations. Sensitivity of MR imaging for detection of deep muscle invasion was 97%, specificity 83%, and accuracy 94%. Sensitivity of MR imaging for detection of extravesical tumor extension was 95%, specificity 100%, and accuracy 97%. Sensitivity for detection of pelvic lymph node metastases was 50%, specificity 100%, and accuracy 82%. Our population included many patients with locally advanced disease. This pattern reflects standards of clinical practice by which superficial lesions are staged and resected endoscopically, and deeply invasive tumors are imaged prior to radical surgery.     

Adenomyosis: US features with histologic correlation in an in-vitro study

PURPOSE: To evaluate the accuracy of ultrasonographic (US) features of adenomyosis by correlating them with histologic findings and to assess inter- and intraobserver agreement. MATERIALS AND METHODS: US was performed and videotaped in 102 consecutive hysterectomy specimens in a water bath. Videotapes were reviewed initially by two independent radiologists blinded to the clinical and histologic findings and after 1 month by one of the two; US and histologic findings were correlated. Features evaluated included diffuse abnormal echotexture of myometrium, subendometrial myometrial cysts, subendometrial echogenic nodules, subendometrial echogenic linear striations, nodular endometrial-myometrial junction, poor definition of the endometrial-myometrial junction, asymmetric thickness of the anteroposterior wall of the myometrium, and globular configuration. RESULTS: The prevalence of adenomyosis in this cohort was 29.4% (30 of 102 specimens). The mean sensitivity, specificity, negative predictive value, positive predictive value (PPV), and accuracy for the diagnosis of adenomyosis for the three reviews were 81%, 71%, 90%, 54%, and 74%, respectively. All findings evaluated, except for nodular endometrial-myometrial junction, were significantly more common in uteri with adenomyosis (P <.05). Heterogeneous myometrium reached borderline significance (P =.05). The specificities and PPVs of subendometrial striations, subendometrial echogenic nodules, and asymmetric myometrial thickness were significantly higher than those of other features (P <.05). The interobserver agreement was moderate (kappa = 0.48), and the intraobserver agreement was good (kappa = 0. 67) for the three reviews. CONCLUSION: The presence of subendometrial linear striations, subendometrial echogenic nodules, or asymmetric myometrial thickness improves the specificity and PPV of US in diagnosing adenomyosis.     

Prognostic parameters in FIGO stage I endometrial carcinoma of endometrioid type

BACKGROUND/AIM: Endometrial carcinoma is the most common malignant neoplasm of the female genital tract in developed countries. Endometrioid carcinoma represents about three-fourths of all endometrial carcinoma. The aim of this study was to examine pathologic parameters, age, and the 5-year survival of the patients with FIGO stage I endometrial carcinoma of endometrioid type and to assess the prognostic utility of age, depth of myometrial invasion, hystologic type (endometrioid or variant), histologic grade, nuclear grade, and lymph-vascular space invasion. METHODS. Age, pathologic parameters, and survival data were retrospectively collected on 236 patients with FIGO stage I endometrial carcinoma of endometrioid type. All the patients underwent hysterectomy between 1996 and 2000 and follow-up until December 2005. RESULTS: A total of 236 patients (mean age 58.0, range 40-79) were analyzed. During the 5-year period of follow-up, 59 (25.0%) patents died from the disease. An univariate analysis revealed that age, depth of myometrial invasion, histologic grade, nuclear grade, and lymph-vascular space invasion were associated significantly with the 5-year survival of the patients. A multivariate analysis revealed that age, lymph-vascular space invasion, and depth of myometrial invasion were associated significantly with the 5-year survival. CONCLUSION: Age, lymph-vascular space invasion, and depth of myometrial invasion are independent prognostic parameters for the 5-year survival of the patients with FIGO stage I endometrial carcinoma of endometrioid type.     

Mixed müllerian sarcoma of the uterus: MR imaging findings

MR images of seven patients with histologically documented mixed müllerian sarcoma were analyzed retrospectively to determine whether the scans showed findings that could suggest the diagnosis. Spin-echo T1- and T2-weighted sagittal and transverse images from either a 0.35- or a 1.5-T unit were available for each patient. MR image analysis included evaluation of tumor signal intensity on T1 and T2 images; tumor location, size, and extent; depth of myometrial invasion; and presence of pelvic metastases. In all seven patients, MR images showed a large endometrial mass deeply invading the myometrium or beyond. In addition, MR images showed intraperitoneal (two patients) and ovarian (one patient) metastases. Although the massiveness of the tumors on initial presentation may suggest the diagnosis of mixed müllerian sarcoma, the MR imaging findings are nonspecific and mimic invasive endometrial carcinoma.     

Endometrial carcinoma: assessment of myometrial invasion with plain and gadolinium-enhanced MR imaging

The purpose of this study was to determine the accuracy of magnetic resonance imaging (MRI) for evaluating the depth of myometrial invasion, potential sources of pitfalls, and the usefulness of contrast-enhanced series. Eighty-five patients with a pathologic diagnosis of endometrial carcinoma underwent preoperative MRI (plain and contrast-enhanced). Grade of myometrial invasion, presence of junctional zone (JZ), fibromyomas, and tumoral thickness were evaluated by two groups of radiologists blinded to pathologic results. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of MRI in determining the depth of myometrial invasion were evaluated. The sensitivity/specificity for plain MR was 64.1-64.1/93.5-100 for both observers. Assessing deep myometrial invasion, sensitivity, and NPV improved significantly (P = 0.002, P = 0.003 for both observers) when comparing plain and whole study series. Tumoral thickness (P = 0.16, P = 0.13, for the two observers) and presence or absence of JZ (P = 0.41, P = 0.14) did not influence myometrial invasion assessment. Gadolinium-enhanced series improve the assessment of deep myometrial invasion in endometrial carcinoma. J. Magn. Reson. Imaging 2000;12:460-466.     

MRI evaluation of myometrial invasion by endometrial carcinoma. Comparison between fast-spin-echo T2w and coronal-FMPSPGR Gadolinium-Dota-enhanced sequences

PURPOSE: The depth of myometrial invasion by endometrial carcinoma strongly affects the incidence of metastasis to regional nodes and influences the surgical strategies. The aim of this paper is to compare the results of FSE T2-w and Gadolinium-enhanced FMPSGR MR sequences in assessing the depth of myometrial invasion by endometrial cancer. MATERIALS AND METHODS: Forty-five women with histopathologically-proven endometrial carcinoma underwent preoperative MRI. Axial SE T1w, axial, sagittal and para-coronal FSE T2w and para-coronal Gadolinium-enhanced FMPSGR sequences were performed using a high field strength magnet (1.5T). Within one month of MR all patients underwent hysterectomy, and anatomical evaluation of the surgical specimen was done sectioning the uterus along the short axis. Based upon the results of the histological evaluation the results of the FSE T2w and Gadolinium-enhanced sequences were compared and the statistical difference between the results obtained was statistically evaluated. RESULTS: The histological evaluation showed intramucosal neoplasm in 11 patients, myometrial infiltration less than 50% in 31 patients, myometrial infiltration more than 50% in 12 patients and transmural cancer in 1 patient. Statistical evaluation showed that the FSE T2w sequence had a global sensitivity and specificity of 80.6% and 87.6%, respectively, with a mean Negative Predictive Value of 92.6% and a mean Positive Predictive Value of 86%. Gadolinium-enhanced FMPSPGR sequence had a global sensitivity and specificity of 90.6% and 93.3%, respectively, with a mean Negative Predictive Value of 96,3% and a mean Positive Predictive Value of 88%. The staging accuracy (chi2 test) on FMPSPGR images (95%) was higher than that on FSE T2w images (78%). CONCLUSIONS: In our experience Gadolinium-enhanced dynamic sequences increase the accuracy of MR imaging in diagnosing the depth of myometrial invasion. In particular they improve the visualisation of the inner myometrium, the so called subendometrial enhancing zone, whose disruption or changes are essential for diagnosing myometrial invasion. The major diagnostic advantages of the enhanced sequences were found in postmenopausal women, where visualisation of the junctional zone may be difficult in the T2w sequences. We believe that Gadolinium-enhanced dynamic sequences should be used whenever the diagnosis is unclear at FSE T2w sequences.     

Primary gastric lymphoma versus gastric carcinoma: endoscopic US evaluation

Endoscopic ultrasonography (US) enables high-resolution imaging of the stomach and can demonstrate the different layers of the gastric wall. It has therefore been proposed for use in evaluating the extension of gastric neoplasms. It was performed in nine patients with primary gastric non-Hodgkin lymphoma and in 36 with gastric carcinoma. The US and pathologic findings were correlated in three surgical specimens of gastric lymphoma. Three different US patterns were found in gastric lymphomas: a polypoid pattern (two cases), localized (two cases) or extended (five cases) hypoechoic infiltration, and thickening with superficial ulcerations. Infiltration was confined to the second and third layers of the gastric wall in six cases and was transmural in three. The study of the gastric lymphoma specimens confirmed the accuracy of US in demonstrating the extent of infiltration. Gastric carcinomas had a more echogenic pattern and a different trend of diffusion, with no extended longitudinal hypoechoic infiltration of the superficial layers or extended hypoechoic transmural infiltration.     

Endometrial carcinoma: multisection dynamic MR imaging using a three-dimensional FLASH technique during breath holding.

PURPOSE: Our aim was to investigate the usefulness of multisection dynamic MR imaging using a 3D FLASH technique during breath holding in assessing myometrial invasion by endometrial carcinoma. MATERIALS AND METHODS: Twenty-eight endometrial carcinomas were evaluated with pathologic correlation. Dynamic MR imaging was performed using the 3D FLASH technique during breath holding. We compared accuracy in the assessment of myometrial invasion by endometrial carcinoma between T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MR images. RESULTS: The accuracy rates in estimating myometrial invasion with T2-weighted images, contrast-enhanced T1-weighted images, and dynamic MR images were 64.3%, 67.8%, and 85.7%, respectively. Statistically significant differences were seen between dynamic MR images and both T2-weighted images and contrast-enhanced T1-weighted images. CONCLUSION: Multisection dynamic MR imaging using the 3D FLASH technique during breath holding is useful for the evaluation of myometrial invasion by endometrial carcinoma with polypoid growth or an unclear junctional zone on T2-weighted images.     

Assessment of depth of myometrial invasion by endometrial carcinoma: comparison of T2-weighted SE and contrast-enhanced dynamic GRE MR imaging

A prospective study was undertaken to assess the value of both T2-weighted spin-echo (SE) and contrast-enhanced dynamic gradient-echo (GRE) sequences using MR imaging in differentiating the deep myometrial invasion from lower stages produced by endometrial carcinoma. For the correlation of MR findings with the histopathologic findings, patients who had no myometrial invasion (stage 1 a) and patients in whom tumors were confined to the superficial myometrium (stage 1 b) at pathologic examination were combined as lower stages. Twenty patients with endometrial carcinoma were studied using both techniques. The absence of any detectable tumor (stage 1 a) or the presence of a tumor confined to inner half of myometrium (stage 1 b) and extention of tumor to the outer half of myometrium (stage 1 c) were used as the diagnostic criteria. In pathologic examination of excised specimens, deep myometrial invasion was detected in 9 of 20 patients. The sensitivity, specificity, accuracy, positive predictive values (PPV) and negative predictive values (NPV) of T2-weighted SE in differentiating deep myometrial invasion from combined lower stages were 88, 91, 90, 88, and 91 %, respectively, whereas corresponding values for contrast-enhanced dynamic GRE sequences were 78, 100, 90, 100, and 85 %. Statistical difference between two sequences did not reach a significant level. We conclude that in cases of absence of visible junctional zone with SE sequence, contrast-enhanced dynamic GRE MR imaging may be helpful. Received 13 December 1996; Revision received 1 July 1997; Accepted 4 July 1997     

Myometrial invasion by endometrial carcinoma: assessment with plain and gadolinium-enhanced MR imaging.

A prospective study was designed to determine the sensitivity and specificity of nonenhanced T2-weighted and contrast material-enhanced T1-weighted magnetic resonance (MR) imaging in assessing the depth of myometrial invasion in patients with proved endometrial cancer. In 56 consecutive patients with clinically determined early-stage disease, findings of the two MR imaging techniques were compared with results of histologic examination of surgical specimens. Myometrial invasion was classified as absent (stage IA), superficial (stage IB), or deep (stage IC). In the assessment of each tumor stage, the sensitivity and specificity of contrast-enhanced T1-weighted MR imaging were higher than those of non-enhanced T2-weighted MR imaging. In determining the degree of myometrial tumor invasion, the overall sensitivity of enhanced T1-weighted MR imaging was 87.5%, whereas that of nonenhanced T2-weighted MR imaging was 71.4% (P less than .05). The use of contrast material may improve the ability to assess, with MR imaging, the depth of myometrial invasion by endometrial cancer.     

Prediction of deep myometrial invasion in patients with endometrial cancer: clinical utility of contrast-enhanced MR imaging-a meta-analysis and Bayesian analysis

PURPOSE: To determine if, in a patient with an endometrial cancer, in addition to the knowledge of tumor grade, preoperative magnetic resonance (MR) imaging findings contribute to treatment stratification and specialist referral. MATERIALS AND METHODS: By using a MEDLINE literature search and institutional pathology reports, pretest probabilities for myometrial invasion were correlated with tumor grade. Likelihood ratios (LRs) were obtained through summary receiver operating characteristics. RESULTS: The mean pretest probabilities of deep myometrial invasion were derived from seven articles (1,875 patients) and from 125 institutional pathology reports. LRs for the prediction of myometrial invasion with contrast-enhanced MR imaging were derived from nine studies (742 patients); positive and negative LRs were 10.11 and 0.1, respectively. The mean weighted pretest probabilities of deep myometrial invasion in patients with tumor grades 1, 2, or 3 were 13%, 35%, or 54%, respectively. Posttest probabilities of deep myometrial invasion for grades 1, 2, or 3 increased to 60%, 84%, or 92%, respectively, for positive and decreased to 1%, 5%, or 10%, respectively, for negative MR imaging findings. CONCLUSION: Use of contrast-enhanced MR imaging significantly affects the posttest probability of deep myometrial invasion in patients with all grades of endometrial cancer and could be used to select patients for specialist referral.     

Bladder cancer: staging with CT and MR imaging

Magnetic resonance (MR) imaging and computed tomography (CT) were compared in 30 patients with histologically proved bladder cancer. MR imaging was accurate in depicting the presence or absence of extravesical spread in 22 patients (accuracy, 73%; sensitivity, 82%; specificity, 62%), and CT was accurate in 24 patients (accuracy, 80%; sensitivity, 94%; specificity, 62%). The MR examinations of two patients were of undiagnostic quality and therefore considered to be technical failures. Each technique resulted in five false-positive and one false-negative examination for the diagnosis of extravesical tumor spread. In 28 patients the integrity of the bladder wall was assessed with MR imaging. In 22 patients the bladder wall was disrupted, and 18 of these patients had deep muscle invasion. In six patients the bladder wall was intact, and none of these patients had evidence of deep muscle invasion at pathologic examination. In this study MR imaging was slightly inferior to CT in the delineation of invasive tumors beyond the bladder wall. However, if one excludes from analysis the two patients with undiagnostic studies, there is no significant difference in accuracy between the two techniques.     

子宫内膜良、恶性息肉样病变的MR表现与临床病理对照分析

目的 探讨常规MR及动态增强扫描在子宫内膜息肉样病变中的诊断价值及病理基础.方法 回顾性分析经病理证实的子宫内膜息肉样病变48例,其中恶性肿瘤26例(23例I期子宫内膜癌和3例子宫内膜肉瘤),良性息肉样病变22例(子宫内膜息肉12例和子宫黏膜下肌瘤10例),分析其MR平扫及增强图像病灶特征,并与病理结果 进行对照.采用Fisher精确概率法对纤维核、囊变区及完整结合带在不同子宫内膜息肉样病变中的出现概率进行分析比较.结果 26例子宫内膜恶性息肉病变,其中23例子宫内膜癌在MR T2WI上均表现为子官内膜均匀等或稍高信号肿块(23/23),增强后相对于肌层均呈低信号(23/23),并伴结合带中断或模糊(20/23);子宫内膜含间质成分恶性肿瘤3例,2例为腺肉瘤,1例为癌肉瘤,MR T2WI均为混杂信号,早期局部明显强化,至后期仍明显持续强化;26例子宫内膜恶性息肉病变在MRI上子宫结合带中断或模糊征象出现的概率(23/26)均较子宫内膜息肉(1/11)及子宫黏膜下肌瘤(1/9)高,差异具有统计学意义(P值均<0.05).肿块内小囊变影及不定形纤维核影见于子宫内膜息肉(分别为8/12及5/12),2种征象在子宫内膜息肉中的出现概率均较子宫内膜恶性息肉样病变(3/26及2/26)及子宫黏膜下肌瘤(0及2/10)高,差异具有统计学意义(P值均<0.05);10例子宫黏膜下平滑肌瘤MRI均表现为境界清晰,T2WI呈等或稍低信号肿块,且出现子宫黏膜推移征象(10/10).MR平扫及增强扫描对所有48例子宫内膜息肉样病变的定性诊断敏感度为92.3%(24/26),特异度为83.3%(20/24),准确度为95.8%(46/48).结论 MRI平扫及增强扫描能反映子宫内膜良、恶性息肉样病变的特征,具有很高的诊断价值.     

An unusual presentation of endometrial polyp

A 33-year-old woman was incidentally found to have a polypoid adenofibroma on MR imaging during the evaluation of carcinoma in situ of the cervix. The position of the polypoid lesion was variable from time to time. Although the lesion was a benign pedunculated one, T2-weighted MR images showed disruption of "junctional zone" in the posterior myometrial wall of the uterus, mimicking myometrial invasion of endometrial carcinoma. Electronic Publication     

Ultrasonographic evaluation of invasive lobular carcinoma.

PURPOSE: To compare ultrasonographic (US) and mammographic findings and tumor size measurements of invasive lobular carcinoma (ILC). MATERIAL AND METHODS: US diagnoses and mammographic findings were compared in 95 patients with pure ILC, including 46 palpable and 49 nonpalpable tumors. The diameters of tumors measured by mammography, US, and pathology were compared in 70 of the 95 patients using scatter plots and correlation analysis. RESULTS: Eighty-two (86.3%) of the ILCs were correctly diagnosed as malignant tumor, 5 (5.3%) were diagnosed as focal abnormality, and only 2 patients had normal findings on US. The most common mammographic findings were a spiculated mass (57%) and a focal asymmetric density (15%). US correctly diagnosed 8 of 12 patients with normal or equivocal mammographic findings. The correlation of tumor size assessment on imaging and pathology revealed that US measurements including the "halo" (r=0.69) was superior to that of mammography (r=0.59). ILCs larger than 30 mm were heavily underestimated by both methods. CONCLUSION: Malignant tumor was diagnosed on US in most of the patients with ILC. US tumor measurement including the "halo" predicted tumor size most accurately. The correlation between imaging measurements and tumor diameter on histology was lower for ILCs than reported for populations of mixed carcinomas.     

MRI of Wilms' tumor: promise as the primary imaging method

The magnetic resonance appearance of Wilms' tumor in 14 patients is described and its clinical utility is evaluated. In all cases, magnetic resonance was correlated with surgical and pathologic findings to assess accuracy. Magnetic resonance accurately identified the primary tumor and its renal origin in all cases, and tumor margins and local extension were accurately demonstrated. Tumor margins were smooth and well defined in nine of 12 cases. Local extension and size were accurately assessed, but because capsular invasion could not be predicted, four surgically proven instances of capsular invasion were missed. Metastatic spread into the liver and inferior vena cava was well documented in four cases and excluded in 10. Magnetic resonance was sensitive for identifying lymph-node enlargement in five of 14 cases, but could not predict the etiology of the enlargement. All Wilms' tumors had signal intensities consistent with prolonged T1 and T2 relaxation times. Signal intensity was highly variable, mainly because of necrosis and hemorrhage within the tumor. Magnetic resonance based on signal intensity could not distinguish Wilms' tumor from other solid renal tumors. Magnetic resonance has the potential for providing the same information as computed tomography, sonography, liver spleen radionuclide scanning, and excretory urography. Although expensive, magnetic resonance will be cost-effective if it can replace all the above techniques. This limited study indicates that magnetic resonance has promise as the primary imaging technique for Wilms' tumors.