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 cancer: accuracy of 3-Tesla magnetic resonance imaging

The purpose of this study was to evaluate the accuracy of 3-Tesla magnetic resonance imaging (MRI) for the preoperative staging of rectal cancer. Thirty-five patients with a primary rectal cancer who underwent preoperative 3-T MRI using a phased-array coil and had a surgical resection were enrolled in the study group. Preoperatively, three experienced radiologists independently assessed the T and N staging. A confidence level scoring system was used to determine if there was any perirectal invasion, and receiver operating characteristic (ROC) curves were generated. The interobserver agreement was estimated using κ statistics. The overall accuracy rate of T staging for rectal cancer was 92%. The diagnostic accuracy was 97% for T1, 89% for T2 and 91% for T3, respectively. The predictive accuracy for perirectal invasion by the three observers was high (Az>0.92). The interobserver agreement for T staging was moderate to substantial. The overall sensitivity, specificity, and accuracy for the detection of mesorectal nodal metastases were 80%, 98%, and 95%, respectively. In conclusion, preoperative 3-T MRI using a phase-array coil accurately indicates the depth of tumor invasion for rectal cancer with a low variability.     

Follow-up Results After Negative Findings on Unenhanced Hepatic MR Imaging for Hepatic Metastasis from Rectal Cancer

Objective

To assess the follow-up results after negative findings on unenhanced hepatic MR imaging in rectal cancer patients who have undergone locally curative surgery.

Materials and Methods

From all pertinent imaging reports and medical records, we selected 255 patients who had negative results on unenhanced hepatic MR imaging. When selecting patients who had undergone curative resection, the following patients were excluded from the study: 1) patients in whom extrahepatic metastases were detected on preoperative staging work-ups, 2) patients in whom the surgery was judged to be non-curative due to peritoneal seeding or local aggressiveness. Cases with follow-up periods of less than 18 months were also excluded, as these cases were considered insufficient to confirm the negative outcomes. Thus, a total of 149 patients were ultimately enrolled in our study. The follow-up results of unenhanced MR imagings were assessed according to the assumption that the newly developed hepatic metastases had been false-negative lesions on preoperative MR image.

Results

During a median follow-up period of 29.3 months, 25 hepatic metastases were detected in 13 patients (8.7%), which indicated a negative predictive value of 91.3%.

Conclusion

Unenhanced hepatic MR imaging provides a high negative predictive value with regard to the detection of hepatic metastasis in the preoperative evaluation of rectal cancer.     

直肠癌术前评估的CT与MRI对照研究

目的 比较CT和MRI在直肠癌术前局部分期中的价值.方法 对经手术病理证实的直肠癌25例,于术前分别行CT和MRI检查,CT采用平扫及增强扫描,MRI序列包括矢状位T2WI,冠状位T2 WI,轴位T1WI及T2 WI,轴位DWI.观察肿瘤对肠壁的侵润深度及范围,肿瘤周围组织结构,淋巴结等方面,将术前影像局部分期结果与术后病理结果进行比较.结果 对于T分期,CT的总诊断准确度为72.0％(18/25),与病理学T分期间一致性检验为较好(kappa=0.439);MRI为88.0％(22/25),与病理学T分期间一致性检验好(kappa=0.760).对于N分期,CT的诊断准确率为72.0％(18/25),与病理学N分期间一致性检验为较好(kappa=0.426);MRI-DWI为84.0 ％(21/25),与病理学N分期间一致性检验为较好(kappa=0.675).结论 在直肠癌术前局部分期中,MRI较CT具有更高的诊断准确度.     

Local radiological staging of rectal cancer

Rectal cancer is a common malignancy with a highly variable outcome. Local recurrence is dependent upon tumour stage and surgical technique. The role of pre-operative imaging is to determine which patients may be safely managed by surgery alone and which need additional therapy in order to facilitate surgery and improve outcome. This decision depends on the distinction between those with early and advanced disease. While trans-rectal ultrasound has traditionally been used to answer this question, a role for magnetic resonance imaging (MRI) is increasingly argued. This review will focus on the treatment options for rectal cancer and the clinical questions that subsequently arise for the radiologist to answer.     

直肠癌CT诊断与分期

目的:评价CT在诊断和直肠癌分期的价值。材料和方法:回顾性分析150例经手术病理证实的直肠癌的CT表现,评价其CT诊断和分期的价值。结果:直肠癌CT的主要表现包括肠壁增厚50例、软组织肿块61例和肠腔狭窄49例;与手术病理对照,CT显示病灶、周围组织侵犯和淋巴结转移的准确性分别为96.7%(145/150)、88.4%(84/95)和51.7%(15/29);CT分期与Dukes分期的总符合率为83.3%。结论:直肠癌的CT诊断和分期与手术病理分期有很好的一致性,CT是直肠癌术前诊断的重要影像检查方法。     

MSCT在胃癌病理分期及诊断中的应用价值

目的：探讨胃癌的 CT 表现特征,评价其在分期诊断中的应用价值。方法：搜集有完整手术病理的胃癌患者500例,通过将 CT 检查结果与胃癌的大小、位置、形状、强化程度以及肿瘤侵犯范围进行对比,对 CT 的分期诊断准确度进行评价。结果：胃癌病灶长度、厚度与病理 T 分期均呈显著正相关（P ＜0．001）。胃癌病灶好发于胃窦及贲门部。500例胃癌患者中最常见的类型为蕈样型（79．0％,395／500）。胃癌病灶在静脉期及延迟期的 CT 值随着 T 分期逐级升高而增大,差异有统计学意义（P ＜0．05）。T3期中胃周脂肪模糊型所占比例为76．64％,T4期中浆膜高强化型所占比例为86．36％。MSCT 诊断胃癌 T1期的准确度为91．23％,T2期准确度为89．01％,T3期准确度为87．64％,T4期准确度为98．74％。结论：MSCT 有助于更准确地判断肿瘤的浸润程度,能够较准确地对胃癌的 T 分期进行判断。     

Accuracy of High-Resolution MRI with Lumen Distention in Rectal Cancer Staging and Circumferential Margin Involvement Prediction

Objective

To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction.

Materials and Methods

Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics.

Results

The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group ≤ T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4).

Conclusion

MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting.     

Rectal carcinoma: Prospective comparison of conventional and gadopentetate dimeglumine enhanced fat-suppressed MR imaging

The purpose of this study is to compare the usefulness of conventional MR imaging and gadopentetate dimeglumine enhanced fat-suppressed MR imaging for the depiction and staging of rectal carcinoma. Thirty-two patients were prospectively evaluated by MR imaging using a 1.5-T unit. Based on the results of a barium study and/or digital examination, a balloon catheter was inserted to the level of the lesion before examination. Both conventional T1- and T2-weighted images and gadopentetate dimeglumine enhanced fat-suppressed T1-weighted images were obtained for all patients. The kappa statistics were performed for the evaluation of interobserver agreement and the McNemar test was performed for the analysis of staging accuracy. When only T1- and T2-weighted images were used, 5 of 32 tumors were not detected and the extent of 18 of 32 tumors were unclear. However, when gadopentetate dimeglumine enhanced fat-suppressed imaging was added, 24 of 32 tumors were well defined and only one tumor was not detected. In determining the depth of invasion, the staging accuracy was 72% for conventional imaging and 68% for all images combined. There was no significant difference between with gadopentetate dimeglumine fat-suppressed imaging and conventional imaging (P > .05). Use of gadopentetate dimeglumine (fat-suppressed imaging) resulted in overestimation of muscular invasion, peri-rectal fat invasion, and adjacent organ invasion in 12 patients, whereas nine patients were overestimated without the use of gadopentetate dimeglumine. In the detection of metastatic lymph nodes, gadopentetate dimeglumine enhanced fat-suppressed imaging also was not useful. Tumor detection was excellent using gadopentetate dimeglumine enhanced fat-suppressed images. However, the accuracy of staging was not improved by obtaining such images.     

The role of PET/CT for evaluating breast cancer.

Positron emission tomography combined with computed tomography (PET/CT) has been receiving increasing attention during the recent years for making the diagnosis, for determining the staging and for the follow-up of various malignancies. The PET/CT findings of 58 breast cancer patients (age range: 34-79 years old, mean age: 50 years) were retrospectively compared with the PET or CT scans alone. PET/CT was found to be better than PET or CT alone for detecting small tumors or multiple metastases, for accurately localizing lymph node metastasis and for monitoring the response to chemotherapy in breast cancer patients.     

18F—氟脱氧葡萄糖显像在肺癌治疗中应用价值的新进展

肺癌的发病率很高,且其预后差,而传统的相关检查对肺癌的确诊、分期、监测疗效和探测肿瘤复发方面存在一定局限性.18F-氟脱氧葡萄糖显像作为一种功能影像已较广泛地应用于临床,由于其一次检查可获得全身图像且在辨别生理性摄取和病理性摄取上有明显优势,故对肺癌的淋巴结及全身远处器官转移均可从不同层面和角度进行观察,从而获得更准确的分期,影响肺癌治疗方案的制定及预后的判断.     

Lobar mucinous bronchioloalveolar carcinoma of the lung showing negative FDG uptake on integrated PET/CT

We present a case of bronchioloalveolar carcinoma manifesting as air-space consolidation with negative FDG uptake on integrated PET/CT in a 42-year-old woman. To know this pattern of uptake especially in the case of mucin-predominant lobar bronchioloalveolar carcinoma may help avoid misdiagnosis of this particular tumor.     

Delayed Colon Perforation after Palliative Treatment for Rectal Carcinoma with Bare Rectal Stent: A Case Report

In order to relieve mechanical obstruction caused by rectal carcinoma, a bare rectal stent was inserted in the sigmoid colon of a 70-year-old female. The procedure was successful, and for one month the patient made good progress. She then complained of abdominal pain, however, and plain radiographs of the chest and abdomen revealed the presence of free gas in the subdiaphragmatic area. Surgical findings showed that a spur at the proximal end of the bare rectal stent had penetrated the rectal mucosal wall. After placing a bare rectal stent for the palliative treatment of colorectal carcinoma, close follow-up to detect possible perforation of the bowel wall is necessary.     

CT、MR对盆腔结、直肠癌术前TN分期的应用价值

目的通过与手术后病理分期对照,比较盆腔CT与MRI对结、直肠癌分期的价值。方法回顾总结经手术治疗的盆腔结直肠癌患者资料51例,术前2-3天内均行盆腔CT与MRI平扫检查。根据CT轴位平扫、增强扫描、冠状位及矢状位重建和MRI中的T2WI、DWI序列轴位、矢状位及冠状位图像进行术前TN分期,并与病理结果比较。结果盆腔CT判断T分期正确40例,总的准确率78.4%,与病理分期比较达到中高度一致,Kappa值=0.642;盆腔MRI判断T分期正确46例,总的准确率90.2%,与病理分期比较达到高度一致,Kappa值=0.808。51例患者N分期为:25例无淋巴结转移,26例有淋巴结转移,盆腔CT与盆腔MRI判断淋巴结转移的准确率为(58.8%vs 66.7%)、敏感性为(53.8%vs 65.4%)、特异性(64%vs 68%)、阳性预测值(53.8%vs 65.4%)、阴性预测值(61.5%vs 68%)都比较相近,盆腔MR对淋巴结转移预测的约等指数高于CT(0.334vs 0.178)。结论 MRI能有效提高结、直肠癌进行术前T分期的准确性,对临床治疗具有指导意义。     

螺旋CT三期增强扫描对胃癌TNM分期的研究

目的　评价螺旋CT三期增强扫描对胃癌TNM分期的诊断价值。方法　胃癌 10 1例进行低张水充盈螺旋CT三期增强扫描。结果　 (1)螺旋CT三期增强扫描对胃癌T -分期、N -分期和TNM分期的准确性分别为 81.8%、72 .9%和 80 .2 %。 (2 )动脉期—门脉期胃壁呈多层结构有利于判断胃癌浸润胃壁的深度 (Ρ <0 .0 5 )。 (3 )平衡期肿瘤强化完全有助于判断有无邻近器官受侵。(4 )以淋巴结直径 >5mm为转移标准 ,螺旋CT诊断转移淋巴结的敏感性明显高于以 10mm为转移标准 (Ρ <0 .0 5 )。结论　螺旋CT三期增强扫描能提高胃癌TNM分期的准确性。     

直肠癌的CT表现及其对术前分期的意义

目的分析直肠癌的CT特征,并评价其诊断意义。方法回顾性分析经手术、病理证实的18例直肠癌病例的临床与CT资料,并依据CT表现对18例直肠癌病变进行了术前CT分期。结果直肠癌的CT表现主要为肠壁增厚,肠腔内肿块,肠腔狭窄,肠周浸润,淋巴结转移。术前CT正确分期15例（83.3%）。结论直肠癌术前CT检查对病变的严重程度的判断,设计合理的治疗和手术计划以及预后的估计具有很高的临床应用价值。     

直肠癌N分期相关影像学因素CT与病理对照研究

目的分析直肠癌淋巴结转移的相关CT表现,探讨与N分期相关的影像学规律。方法术前行盆腔CT检查的直肠癌病例59例,男38例,女21例,年龄36～80岁,中位年龄58岁。对切除标本进行淋巴结切片检查,以病理学诊断转移淋巴结阳性数为标准,按照美国癌症联合会(AJCC)N分期定义分为pN0、pN1、pN2组。采用影像工作站电影回放方式对所有病人图像进行复阅,观察盆腔淋巴结数目、大小、分布、原发肿瘤的浆膜表现及是否环周生长等情况,由2位放射医生盲法阅片并达成一致。统计方法选用KruskalWallis秩和检验及χ2检验。结果所有淋巴结转移阳性病例在CT均有淋巴结显示,pN0、pN1及pN2组CT检出的最大淋巴结径线随转移程度进展逐渐增大,分别为(4.13±3.21)mm、(7.43±3.27)mm和(10.27±3.88)mm,差异有统计学意义(χ2=23.842,P<0.01);pN0、pN1及pN2组CT检出淋巴结数目随转移程度进展逐渐增多,平均数目分别为(3.40±2.75)枚、(5.07±3.02)枚、(8.93±2.99)枚,差异有统计学意义(H=21.834,P<0.01);各组检出淋巴结的径线其差异有统计学意义(H=32.037,P<0.001)。单纯直肠旁淋巴结显示、肠旁和直肠上动脉旁同时显示及合并髂血管旁淋巴结显示的淋巴结转移分别为3例(3/12),17例(17/29)和8例(8/11),淋巴结分布方式在pN0、pN1、pN2组差异有统计学意义(χ2=19.517,P<0.05)。直肠癌淋巴结转移组CT表现为浆膜异常及环周生长者均高于非转移组,差异有统计学意义(χ2=8.979,P<0.01;χ2=5.107,P<0.05)。结论直肠癌淋巴结有无转移及转移程度不仅与淋巴结大小有关,还与淋巴结CT检出数目和淋巴结分布方式及癌肿浆膜和(或)外膜、环周生长情况有关。综合分析CT检出淋巴结的大小、数量、分布、癌肿浆膜和(或)外膜及环周生长等相关因素有助于提高CT直肠癌N分期的准确性。