Rectal carcinoma: double-contrast MR imaging for preoperative staging

PURPOSE: To evaluate and compare the imaging findings and staging of rectal carcinoma by using conventional magnetic resonance (MR) imaging, MR imaging with an enema of superparamagnetic ferristene-based contrast material, and MR imaging with an enema of ferristene solution plus intravenous injection of gadodiamide. MATERIALS AND METHODS: Twenty-nine patients (17 women, 12 men; age range, 39-91 years) referred with a diagnosis of rectal carcinoma were examined. Analysis of the rectal wall and staging of the tumor were performed. In all patients, the MR imaging findings were correlated with the histopathologic findings. RESULTS: The contrast material enema caused distention of the rectum and an intraluminal signal void, whereas the gadodiamide injection caused enhancement of the mucosa on T1-weighted images. This enhancement enabled evaluation of the normal rectal wall and differentiation of the mucosa, tunica muscularis, and perirectal space, which was not possible on the nonenhanced images. Double-contrast (ferristene solution plus gadodiamide) MR imaging was superior to imaging with only ferristene-based contrast material and had a sensitivity of 100%, specificity of 70%, and accuracy of 90% in distinguishing tumor stages worse than Dukes A. CONCLUSION: Double contrast material-enhanced MR imaging enables accurate rectal carcinoma staging, which is not possible at nonenhanced imaging.     

Prostatic carcinoma: staging with MR imaging at 1.5 T

Magnetic resonance (MR) imaging was used to stage prostatic carcinoma in 81 patients with a proved diagnosis. MR imaging findings were correlated with histologic findings regarding the local extent of disease (37 patieNts) and the presence of nodal metastases (51 patients). Tumor nodules were detected in the peripheral zone (PZ) in 34 of 37 patients and were of low signal intensity compared with the signal of the PZ. Hemorrhage in the PZ represented a problem in tumor detection and in tumor volume measurement. When multiple criteria for local tumor spread were combined, MR imaging had a sensitivity of 72%, a specificity of 84%, and an accuracy of 78% in the differentiation of stage A or B from Stage C or D disease. Assessment of seminal vesicle invasion was more accurate than assessment of direct extracapsular spread. In five patients, microscopic invasion of the capsule (stage C) was classified as stage B with MR imaging; from a clinical standpoint, this should not affect patient treatment and prognosis. The MR imaging sensitivity in the detection of lymph node metastases was 69%, with a specificity of 95% and an accuracy of 88%. In this study MR imaging proved reliable in the comprehensive evaluation and staging of prostatic carcinoma.     

Clinical stage B prostate carcinoma: staging with MR imaging

Magnetic resonance (MR) imaging studies were performed in 29 patients with clinical findings of stage B prostatic carcinoma with use of both T1 and T2-weighted spin echo sequences. MR imaging findings were correlated with surgical/pathologic results in 18 patients who underwent an operation. Periprostatic fat, periprostatic venous plexus, seminal vesicles, and lymph nodes were assessed from MR imaging studies. When each was assessed independently, the periprostatic fat signal had a sensitivity of 29%, specificity of 100%, and accuracy of 85% in detecting extracapsular tumor extension, whereas the periprostatic venous plexus had a sensitivity of 57%, specificity of 86%, and accuracy of 80%. MR imaging had a sensitivity of 50%, specificity of 97%, and accuracy of 89% for detecting seminal vesicular involvement. When all four anatomic features were taken into consideration, MR imaging had an accuracy of 89% (16 of 18 patients) in differentiating stage B from stage C or D disease (sensitivity 87%, specificity 90%). Our data indicate that MR imaging is a promising method for staging prostatic carcinoma.     

Prostatic carcinoma: staging by clinical assessment, CT, and MR imaging

The sensitivity, specificity, accuracy, and positive and negative predictive values of clinical assessment, computed tomography (CT), and magnetic resonance (MR) imaging were compared in the differentiation of stage B from stage C prostatic carcinoma. Forty-six patients who had undergone radical prostatectomy were included in the study. Surgical-pathologic staging was considered the "truth measure." Clinical staging had an accuracy of 61%, and CT, 65%. Accuracy for MR imaging depended on the instrument parameters and plane of section used. When only transverse T1-weighted images were analyzed, MR accuracy was 61%. However, when transverse T1- and T2-weighted images supplemented by additional T2-weighted coronal or sagittal images were studied, accuracy increased to 83%. At present, MR imaging is the most accurate diagnostic modality for the local staging of carcinoma of the prostate, but for optimal results, multiple sequences and two orthogonal planes of imaging are needed.     

Endometrial polyps: MR imaging features and distinction from endometrial carcinoma

PURPOSE: To determine the magnetic resonance (MR) imaging characteristics of endometrial polyps and the accuracy of MR imaging in distinguishing endometrial polyps from endometrial carcinomas in a case-control study. MATERIALS AND METHODS: Cross-referencing pathology records with MR studies from two institutions disclosed 35 patients with surgically proved endometrial polyp or carcinoma after controlling for tumor size. All MR examinations were performed at 1.5 T with T2-weighted fast spin-echo sequences in multiple planes. Three independent readers blinded to histologic diagnoses and clinical data scored each image for the presence of several defined findings. RESULTS: A central fibrous core (low signal intensity on T2-weighted images) and intratumoral cysts (high signal intensity on T2-weighted images) were seen more frequently in endometrial polyps than in carcinomas; myometrial invasion and necrosis showed high predictive value for carcinomas. The readers' responses showed a mean sensitivity of 79%, specificity of 89%, accuracy of 86%, positive predictive value of 82%, and negative predictive value of 88% for diagnosis of carcinoma. The mean area under the receiver operating characteristic curve for the three readers was 0.87 for the diagnosis of carcinoma. CONCLUSION: MR images can help to distinguish most polyps from endometrial carcinomas on the basis of morphologic features. Accuracy does not appear to be sufficient to obviate biopsy, partly because carcinomas and polyps frequently coexist.     

Comparing MR imaging and CT in the staging of gastric carcinoma

OBJECTIVE: The purpose of this study was to assess the usefulness of breath-hold two-dimensional (2D) fast low-angle shot (FLASH) and T2-weighted turbo spin-echo fast MR imaging compared with helical CT in the staging of gastric carcinoma. SUBJECTS AND METHODS: Thirty patients with gastric carcinoma underwent preoperative MR imaging and helical CT. MR imaging at 1.5 T was performed immediately after the intramuscular injection of scopolamine and the oral administration of water or effervescent granules. Breath-hold 2D FLASH T1-weighted images in all three planes, turbo spin-echo T2-weighted axial images, and gadolinium-enhanced fat-suppressed 2D FLASH axial images were included. Helical CT was performed 60 sec after initiation of i.v. contrast medium injection (2.5-3 ml/sec). Two groups of two radiologists each independently analyzed the MR and helical CT findings, and these results were compared with the pathologic findings. RESULTS: For T staging, MR imaging accuracy was higher than that of helical CT (73.3% and 66.7%, respectively); however, the accuracies of the two methods were not significantly different from each other (McNemar test, p > 0.05). Overstaging was noted in 6.7% of cases with MR imaging and 10% with helical CT. Understaging was noted in 20% of cases with MR imaging and 23.3% with helical CT. For N staging, the accuracies of MR imaging and helical CT were 55% and 58.6%, respectively, with no statistical significance (overstaging, 10% and 6.9%; understaging, 34.5% and 34.5%, respectively). CONCLUSION: MR imaging was comparable to helical CT in the T and N staging of gastric cancer.     

MR imaging of cervical carcinoma: a practical staging approach.

Cervical carcinoma is the third most common gynecologic malignancy and is typically seen in younger women, often with serious consequences. The International Federation of Gynecology and Obstetrics (FIGO) staging system provides worldwide epidemiologic and treatment response statistics. However, there are significant inaccuracies in the FIGO staging system, and magnetic resonance (MR) imaging, although not included in that system, is now widely accepted as optimal for evaluation of important prognostic factors such as lesion volume and metastatic lymph node involvement that will help determine the treatment strategy. MR imaging examination obviates the use of invasive procedures such as cystoscopy and proctoscopy, especially when there is no evidence of local extension. Brachytherapy and external beam therapy are optimized with MR imaging evaluation of the shape and direction of lesion growth. In general, T2-weighted MR imaging more clearly delineates cervical carcinoma and is preferred for evaluation of the lymph nodes. Dynamic gadolinium-enhanced T1-weighted imaging may help identify smaller tumors, detect or confirm invasion of adjacent organs, and identify fistulous tracts. MR imaging staging, when available, is invaluable for identifying important prognostic factors and optimizing treatment strategies.     

Rectal carcinoma: thin-section MR imaging for staging in 28 patients

PURPOSE: To evaluate the accuracy of thin-section magnetic resonance (MR) imaging (in-plane resolution, 0.6 x 0.6 mm) in the preoperative assessment of the depth of extramural tumor infiltration, which is a major prognostic indicator in rectal cancer. MATERIALS AND METHODS: In a prospective study of 28 consecutive patients, preoperative MR imaging was performed. The tumor stage according to the TNM classification system and the measured depth of extramural tumor invasion in matched MR images and histopathologic slices were compared. RESULTS: Preoperative MR imaging correctly indicated the histopathologic tumor stage in all 25 patients in whom comparisons were possible. The difference between the depth of extramural tumor measured on preoperative MR images and corresponding measurements on histopathologic slices of the resection specimen ranged from -5.0 mm to +5.5 mm (mean difference, +0.13 mm; 95% CI: -2.72, +2.98 mm), indicating good agreement. The mesorectal fascia, and the relation of the tumor to it, could be visualized in every case. In all five patients with involvement of the circumferential excision margins of resection specimens, extensive extramural invasion was identified on preoperative MR images. CONCLUSION: Preoperative thin-section MR imaging accurately indicates the tumor stage of rectal cancer and depth of extramural tumor infiltration. It provides valuable information for identifying T3 tumors for preoperative adjuvant therapy in patients who are at high risk of failure of complete excision.     

MRI在直肠癌术前TNM分期中的应用价值

直肠癌术前准确的分期是切除术成功的关键。MRI是直肠癌术前分期诊断最重要的检查方法之一,通过MRI准确的术前分期,可以准确评估肿瘤浸润的深度和淋巴结转移,了解肿瘤与直肠系膜、直肠系膜筋膜的关系,在全直肠系膜切除术(TME)之前准确预测环状切缘(CRM),为临床诊断和治疗提供更多有价值的信息。就MRI应用于直肠癌术前TNM分期的研究进展进行综述。     

动态增强MRI在中下段直肠癌T3分期中的应用研究

目的探讨动态增强 MRI 在中下段直肠癌 T3分期中的价值.方法本研究共纳入84例中下段直肠癌病人,包括经病理证实为 T3期直肠癌的66例.所有病人术前均接受动态增强 MRI 检查.分析 T3期直肠癌局部浸润的 MRI 征象,进行影像-病理对照,计算动态增强 MRI 诊断 T3分期的准确度、敏感度、特异度、阳性预测值和阴性预测值.对直肠系膜内癌性与非癌性索条影在边缘和强化形式上的差异进行统计学分析.结果 MRI 对中下段直肠癌 T3分期的诊断准确度、敏感度、特异度、阳性预测值和阴性预测值分别为86.90%、90.91%、72.22%、92.31%和68.42%.直肠系膜内癌性与非癌性索条影在边缘和强化形式上的差异均有统计学意义(P<0.05).在判断 T3期直肠癌局部浸润深度时,将直肠系膜内癌性索条影误判为非癌性索条影是导致分期不足的主要原因.结论通过分析直肠系膜内异常索条影的边缘及强化形式有助于提高中下段直肠癌 T3分期的准确性.     

MR staging of endometrial carcinoma

Endometrial cancer is the second most common gynaecological malignancy. The usual presentation with post-menopausal bleeding results in an early diagnosis in most cases and thus there is opportunity for cure. Magnetic resonance (MR) imaging is pivotal in the decision-making process regarding treatment options. We present a review of the magnetic resonance (MR) findings to illustrate its role in the staging of endometrial cancer.     

Diagnosis and staging of gallbladder carcinoma. Evaluation with dynamic MR imaging

The purpose of this study is to determine the ability of dynamic magnetic resonance imaging (MRI) in the diagnosis and staging of gallbladder cancer (GBC). Images of dynamic MRI of hepatobiliary system combined with MR cholangiography (MRC) of 18 patients with pathologically proved gallbladder cancer were correlated with pathological and operative findings. Focal or diffuse wall thickening was present in 10 patients. In five patients, the tumor appeared as a fungating or intramural mass. A tumor replacing the gallbladder was found in two patients and a small cancer in cystic duct in one patient. The tumor featured early and irregular enhancement, which persisted throughout the dynamic study. Metastatic nodes were found by surgicopathology in 13 patients and were depicted by the dynamic MRI in 11 patients. Local invasion to liver was found by surgery in 12 patients and correctly detected by MRI in 11 patients. MRI detected duodenum invasion in three out of six patients and none of the three cases with omental metastasis. In conclusion, dynamic MRI is useful and reliable in staging of advanced gallbladder cancer. MRI combined with MRC is sensitive in detection of obstructive jaundice, liver invasion as well as liver and lymph nodes metastasis. It is more difficult to delineate the invasion to duodenum and omental metastasis by MRI.     

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.     

Local-regional staging of endometrial carcinoma: role of MR imaging in surgical planning

PURPOSE: To assess magnetic resonance (MR) imaging in depicting the depth of myometrial infiltration, cervical invasion, and presence of enlarged lymph nodes in patients with endometrial adenocarcinoma compared with surgicopathologic findings. MATERIALS AND METHODS: Thirty-seven consecutive patients with endometrial carcinoma were included in this prospective study. All patients underwent MR imaging and surgery. Qualitative image analysis included the depth of myometrial infiltration, infiltration of the uterine cervix, and presence of enlarged lymph nodes. Quantitative image analysis included tumor and myometrium contrast-to-noise ratios during different phases of dynamic imaging. MR imaging findings were compared with surgicopathologic findings. Sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values of MR imaging in depicting myometrial and cervical infiltration and in lymph node assessment were calculated. RESULTS: Respective sensitivity, specificity, diagnostic accuracy, and positive and negative predictive values in assessing myometrial infiltration were 87%, 91%, 89%, 87%, and 91%; those for cervical infiltration, 80%, 96%, 92%, 89%, and 93%; and those for lymph node assessment, 50%, 95%, 90%, 50%, and 95%. There was significant agreement between MR imaging and surgicopathologic findings in assessment of myometrial invasion (P <.001). Myometrial and cervical invasion and lymph node enlargement were correctly assessed with MR imaging in 28 (76%) of 37 patients. Quantitative analysis showed a significant improvement in tumor and myometrium contrast-to-noise ratios during the equilibrium phase compared with the arterial and precontrast phases (P <.001). CONCLUSION: MR imaging coupled with contrast material-enhanced dynamic MR imaging is highly accurate in local-regional staging of endometrial carcinoma; more challenging is the assessment of pelvic and lumboaortic lymph nodes.     

Preoperative local staging of rectal carcinoma with MR imaging and a rectal balloon

Magnetic resonance (MR) imaging for the preoperative assessment of rectal carcinoma was evaluated. Thirty-three patients underwent MR imaging with a 1.5-T unit. On the basis of results of barium enema studies and/or digital examination, a balloon catheter was inserted to the level of the lesion before MR imaging. Both T1-and T2-weighted axial spin-echo images were obtained in all patients. With the balloon catheter, the three layers of the normal bowel wall could be seen on T2-weighted images. Muscular invasion was detected with a sensitivity of 90%, a specificity of 84%, a positive predictive value of 90%, a negative predictive value of 84%, and an overall accuracy of 88%. False-positive results were related to chemical shift artifact and intramural lymph node metastases. Perirectal fat invasion was detected with a sensitivity of 64%, a specificity of 89%, a positive predictive value of 82%, a negative predictive value of 77%, and an overall accuracy of 79%. One of the false-positive results was related to intramural lymph node metastases and the other to perirectal vessels. Evaluation of adjacent organ invasion was accurate in all patients. Lymph node metastasis was correctly detected in six of nine patients. Absence of lymph node metastasis was correctly predicted in 23 of 24 patients. Thus, MR imaging with a balloon catheter was useful for detection of tumor invasion into muscularis propria and adjacent organs; however, its demonstration of perirectal fat and lymph node involvement was less accurate.     

Preoperative staging of rectal carcinoma with MR imaging: surgical and histopathologic correlation

Twenty-nine patients with rectal carcinoma were examined with magnetic resonance (MR) imaging at 1.0 T. In most patients a Helmholtz coil was used and a bowel distention obtained with a barium enema balloon tip. The MR findings were graded according to the modified Astler-Coller staging classification and correlated with the surgical or histopathologic results. Correct diagnosis was made in nine of the 12 patients with stage A and B1 tumors. Overestimation occurred in the other three patients, who had previously undergone radiation therapy or surgery. Local stage was correctly assessed in 11 patients with stage B2 carcinoma and in six patients with stage B3 tumors. Enlarged lymph nodes were detected in four of seven patients with nodes containing carcinoma. In two other patients with enlarged nodes, no carcinoma was identified at histologic examination. MR imaging may enable correct staging of local extent of rectal carcinoma, particularly in patients who have not previously undergone radiation therapy or surgery. However, evaluation of lymph nodes is less accurate.