宫颈癌的MRI诊断与分期研究

目的 探讨宫颈癌的MRI表现，前瞻性评价MR成像对宫颈癌术前分期的价值。方法 98例经病理证实的宫颈癌患者行MR检查，其中45例进行了手术，术前3－15d（平均7．5d)内行盆腔的轴面SE T1WI，轴面及矢状面快速自旋回波（TSE）T2WI，冠状面脂肪抑制（SPIR）TSE T2WI以及钆喷替酸葡甲胺（Gd-DTPA)增强后轴面、冠状面、矢状面SE T1WI扫描。在MR图像上观察原发肿瘤的位置、信号特征及侵犯范围。MRI所见与手术病理所进行对比。结果 宫颈癌的MRI表现颇具特征性，T2WI呈较高信号，与宫颈基质低信号及子宫内膜、宫旁脂肪组织高信号有良好对比，T1WI呈等或低信号，Gd-DTPA增强后T1WI可轻度强化。33例出现信号不均匀表现，病理上可为假腺腔、坏死及角化珠。MRI对宫颈癌部位判断的准确度为100％。对宫旁侵犯判断的准确度为88．9％，特异度为90．6％，敏感度为84．6％。对宫颈癌分期总的准确度为88．9％。结论 MRI能多方位清晰显示宫颈癌瘤灶及侵犯范围与途径，明显优于其他影像学检查方法，MRI对术前宫颈癌分期明显优于临床，应成为宫颈癌术前常规的影像检查方法。     

评价MRI在宫颈癌诊断及分期中的应用价值

目的:探讨MR成像对宫颈癌诊断及分期的应用价值。方法:128例(手术49例)经病理证实的宫颈癌患者(鳞癌119例,腺癌8例,鳞腺癌1例)行盆腔轴位SE T1WI,轴位、矢状位及冠状位FSE T2WI,轴位、矢状位及冠状位T2WI脂肪抑制(FRFSE),轴位、矢状位及冠状位T1WI脂肪抑制(FSPGR/70)Gd-DTPA增强扫描。分析宫颈癌MRI的表现及侵犯范围,49例MRI术前分期与手术、病理分期对照。结果:宫颈癌的MRI T2WI呈较高信号,T2WI宫颈癌与宫颈基质低信号及宫旁脂肪组织高信号有良好的对比,T1WI呈等或低信号,Gd-DTPA增强后T1WI呈均匀或不均匀强化,MRI对宫旁侵犯判断的准确率为87%,特异性为89%,敏感性为85%,Ⅰ~Ⅱa期宫颈癌MRI分期准确率为92%,对宫颈癌分期总的准确率为86%。结论:MRI能多方位清晰显示宫颈癌瘤灶及其侵犯范围,术前分期优于其它检查方法,理应成为宫颈癌首选的影像检查方法。     

磁共振成像对宫颈癌的诊断与分期研究

目的 探讨MRI在宫颈癌诊断和分期中的临床价值：方法回顾性分析了35例宫颈癌患者的MRI分期，并与临床分期和手术结果对照。结果 MR能清晰显示宫颈癌的准确部位、实际大小、以及与周围的关系。对Ib-Ⅳ期宫颈癌MRI术前分期的准确度为78．6％（22／28）。对宫旁浸润区分的准确度为94．3％，特异度为958％，敏感度为90．9％。结论官颈癌的MR诊断与分期明显优于临床，能为手术方案的制定提供依据。     

Primary staging of urinary bladder carcinoma: the role of MRI and a comparison with CT

Since the introduction, pelvic MRI has been considered the best non-invasive technique for primary staging of urinary bladder cancer. Before using MRI an understanding of normal and pathological MR images of the urinary bladder is essential. This review therefore describes the MR anatomy of the urinary bladder as well as the appearances of carcinoma. MRI plays an important clinical role in staging the primary tumour. In superficial tumours, clinical staging, which includes transurethral biopsy, is the best technique. For invasive tumours, MRI is superior to other techniques such as CT scanning, transvesical ultrasonography and clinical staging. A limitation of both MRI and CT scanning is their inability to recognize minimal tumour growth in the muscle layer of the bladder wall, or to differentiate between post-transurethral resection oedema and tumour. Therefore, in all patients with urinary bladder cancer staging should preferably start with MRI followed by clinical staging. Unfortunately, however, because of the high cost of this strategy, MRI has to be reserved for staging deeply invasive and superficial poorly differentiated tumours. Correspondence to: J. O. Barentsz     

MRI staging of low rectal cancer

Low rectal tumours, especially those treated by abdominoperineal excision (APE), have a high rate of margin involvement when compared with tumours elsewhere in the rectum. Correct surgical management to minimise this rate of margin involvement is reliant on highly accurate imaging, which can be used to plan the planes of excision. In this article we describe the techniques for accurate magnetic resonance imaging (MRI) assessment and a novel staging system for low rectal tumours. Using this staging system it is possible for the radiologist to demonstrate accurately tumour-free planes for surgical excision of low rectal tumours.     

Delineation of liver necrosis using double contrast-enhanced MRI

The purpose of this study was to demonstrate the potential usefulness of the combination of gadolinium and dysprosium to enhance the difference between normal and necrotic liver tissue. Small regions of acute necrosis were induced by injecting 200–300 μl of 95% alcohol into the liver of 26 rats. MRI was performed 24 hours after necrosis induction, before and immediately after injection of one or both contrast agents. Using a mixed T1/T2-weighted sequence, the signal intensity (SI) of the normal liver was reduced by 70%, whereas the necrotic regions had more than a 50% increase in SI after double contrast. The region that was enhanced corresponded largely with the region of necrosis as observed postmortem. The lesion size, when identified, was largely underestimated using either of the agents alone, albeit using the common pulse sequences. The double contrast effect of simultaneous administration of gadolinium and dysprosium allows accurate delineation of liver necrosis.     

Value of fusion of PET and MRI for staging of endometrial cancer: Comparison with F-FDG contrast-enhanced PET/CT and dynamic contrast-enhanced pelvic MRI

Purpose

To investigate the diagnostic value of retrospective fusion of pelvic MRI and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET images for assessment of locoregional extension and nodal staging of endometrial cancer.

Materials and methods

Thirty patients with biopsy-proven endometrial cancer underwent preoperative contrast-enhanced PET/CT (PET/ceCT) and pelvic dynamic contrast-enhanced MRI for initial staging. Diagnostic performance of PET/ceCT, contrast-enhanced MRI, and retrospective image fusion from PET and MRI (fused PET/MRI) for assessing the extent of the primary tumor (T stage) and metastasis to regional LNs (N stage) was evaluated by two experienced readers. Histopathological and follow-up imaging results were used as the gold standard. The McNemar test was employed for statistical analysis.

Results

Fused PET/MRI and MRI detected 96.7% of the primary tumors, whereas PET/ceCT detected 93.3%. Accuracy for T status was 80.0% for fused PET/MRI, and MRI proved significantly more accurate than PET/ceCT, which had an accuracy of 60.0% (p = 0.041). Patient-based sensitivity, specificity and accuracy for detecting pelvic nodal metastasis were 100%, 96.3% and 96.7% for both fused PET/MRI and PET/ceCT, and 66.7%, 100% and 96.7% for MRI, respectively. These three parameters were not statistically significant (p = 1).

Conclusion

Fused PET/MRI, which complements the individual advantages of MRI and PET, is a valuable technique for assessment of the primary tumor and nodal staging in patients with endometrial cancer.     

MRI在直肠癌术前T分期中的误判分析

目的:探讨MRI在直肠癌术前T分期中的常见误判原因。方法:选择32例经手术病理证实的直肠癌患者,术前均行MRI检查,MRI序列包括常规T1WI、T2WI及STIR。分析直肠癌患者MRI分期,并对照患者术后病理学分期,评估其一致性。结果:直肠癌的术前MRI分期与术后病理学分期的一致性较好(Kappa=0.64,P<0.001)。MRI术前分期误判率为25%,其中,4例pT2期(病理分期为T2期)过度分期为T3期;3例pT3期(病理分期为T3期)低分期为T2期,1例pT3期过度分期为T4期。结论:在直肠癌MRI术前T分期中,正确认识常见误判原因有利于临床治疗方案的制定。     

增强螺旋CT扫描技术在胃癌诊断和分期中的应用

目的 探讨胃癌螺旋CT增强特征及增强扫描技术在胃癌诊断和分期中的作用。方法 对照分析50例胃癌患者的CT增强表现和术后的病理结果。患者CT扫描前30min饮水1000～1500ml，扫描前5～10min肌注山莨菪碱10mg，均行CT平扫和增强扫描。结果 胃癌的CT表现为胃壁局部或弥漫性增厚、软组织块影和固定的狭窄胃腔，部分病例合并癌性溃疡，并侵犯邻近组织，可有邻近或远处淋巴结肿大转移。病灶好发于贲门和胃窦部，增强扫描时病灶较平扫更明显，并有显著强化。CT分期的准确率达86％，淋巴结转移的检测率为60％。结论 螺旋CT增强扫描技术是诊断胃癌和对胃癌进行分期的一种可靠方法，有助于临床更好地治疗胃癌患者。     

Current relevance of cervical ultrasonography in staging cancer of the esophagus and gastroesophageal junction

PURPOSE: To evaluate the value of external ultrasonography (US) of the neck in current dedicated preoperative staging of patients with cancer of the esophagus and gastroesophageal junction (GEJ). MATERIALS AND METHODS: We analyzed 180 consecutive patients (154 men, 26 women, and mean age 63 (38-84) years) without palpable cervical lymphadenopathy, treated between January 2001 and March 2006. Suspicious lesions were confirmed by cytological examination. All first 125 consecutive patients (group A) were staged by standard endoscopic ultrasonography (EUS), multidetector computed tomography (md-CT), positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) and external US. The other 55 patients (group B) were prospectively staged according to a revised protocol consisting of routine EUS and md-CT, while PET was only performed in subjects with T3-T4 and/or N1 disease and external US solely on indication. RESULTS: Cervical metastases were found in seven patients from group A (6%) and in five from group B (9%). Twenty percent (4/20) of the tumors above the carina and 5% (8/160) of the distal tumors presented with cervical metastases. All were diagnosed as T3 and T4 tumors on EUS. Eleven of these metastases were detected by external US and nine on md-CT. All nodal metastases were detected by the combination of PET and md-CT. No cervical metastases were missed by the diagnostic algorithm in group B. CONCLUSION: In present staging procedures for esophageal cancer, routine external US seems to have no additional value in detecting cervical metastases. It is still indicated to obtain cytological proof of suspected cervical lesions.     

Local staging of rectal cancer: the current role of MRI

With the advent of powerful gradient coil systems and high-resolution surface coils, magnetic resonance imaging (MRI) has recently extended its role in the staging of rectal cancer. MRI is superior to endorectal ultrasound, the most widely used staging modality in patients with rectal tumors, in that it visualizes not only the intestinal wall but also the surrounding pelvic anatomy. The crucial advantage of MRI is not that it enables exact T-staging but precise evaluation of the topographic relationship of a tumor to the mesorectal fascia. This fascia is the most important anatomic landmark for the feasibility of total mesorectal excision, which has evolved into the standard operative procedure for the resection of cancer located in the middle or lower third of the rectum. MRI is currently the only imaging modality that is highly accurate in predicting whether or not it is likely that a tumor-free margin can be achieved and thus provides important information for planning of an effective therapeutic strategy, especially in patients with advanced rectal cancer.     

子宫颈癌的MRI诊断及分期

目的探讨MRI分期在子宫颈癌诊断和治疗中的临床意义。方法对我院妇科子宫颈活检证实的72例子宫颈癌患者于临床症状出现后行MRI检查。由二位MRI诊断医师分别对每例患者的图像资料进行分析记录，包括病灶的部位、大小、浆膜有否受累、是否侵及子宫旁、周围器官是否侵及和淋巴结肿大情况，并依据Sironi’s提出的分期方法进行了MRI分期。根据MRI的分期结果，51例子宫颈癌接受了手术治疗，并将手术后病理分期结果与MRI的分期结果进行了比较。结果72例活检证实的子宫颈癌，MRI均发现了病灶。51例手术病例中，44例的MRI分期结果与术后病理分期结果相吻合。总的MRI分期的符合率为86．4％。结论对Ⅰa期以上的子宫颈癌，MRI均可以显示病灶，并可以进行合理分期。如把子宫颈癌的MRI分期合理应用于子宫颈癌的诊治，对其治疗方法的选择有重要意义。     

Challenges in dynamic contrast-enhanced MRI imaging of cervical lymph nodes to detect metastatic disease

PURPOSE: To identify and overcome challenges in using dynamic contrast-enhanced magnetic resonance imaging (MRI) to distinguish tumor from nontumor in the cervical lymph nodes of patients with squamous cell carcinoma of the head and neck. MATERIALS AND METHODS: Signal-to-noise ratio (S/N), motion, node heterogeneity, and tissue normalizations were examined. Twenty-one patients with squamous cell carcinoma of the head and neck were scanned before a neck dissection (two-dimensional fast spoiled gradient-echo: 10 locations/13 seconds). Peak time, peak enhancement, maximum upslope, and washout slope were measured in pathologically confirmed tumor and nontumor nodes and in the submandibular gland and the sternocleidomastoid muscle. RESULTS: Surface coil arrays provided high coverage and high S/N. Motion averaged 1.1 pixels and was corrected. Large tumor nodes were heterogeneous in their contrast enhancement, while the nontumor nodes were homogeneous. The contrast enhancement parameters were significantly different for all regions except for the submandibular gland compared to the nontumor nodes. CONCLUSION: Challenges of dynamic imaging of cervical lymph nodes were overcome and significant differences were found between the tumor and nontumor nodes, indicating that dynamic imaging is feasible and may aid this patient population.     

Diffusion-weighted MRI in cervical cancer

The purpose was to investigate the potential value of apparent diffusion coefficient (ADC) measurement with MRI in the assessment of cervix cancer. Diffusion-weighted MRI was performed in 47 patients with cervical carcinoma undergoing chemoradiation therapy and 26 normal controls on a 1.5-T system with a b-value of 600 s/mm². FIGO stage, tumor volume, nodal status, interstitial fluid pressure (IFP) and oxygen measurements were recorded. Response was defined as no visible tumor 3–6 months following completion of therapy. The average median ADC (mADC) of cervical carcinomas (1.09±0.20×10⁻³ mm²/s) was significantly lower than normal cervix (2.09±0.46×10⁻³ mm²/s) (P<0.001). There was no correlation between mADC, nodal status, tumor volume, IFP or oxygen measurements. mADC was significantly lower in FIGO stages T1b/T2a (0.986 × 10⁻³ mm²/s) compared to T2b (1.21×10⁻³ mm²/s) and T3/T4 (1.10×10⁻³ mm²/s) (P<0.001). In patients with squamous carcinomas the 90th percentile of ADC values was lower in responders than non-responders (P<0.05). Median ADC in cervix carcinoma is significantly lower compared to normal cervix. ADC may have predictive value in squamous tumors, but further long-term study will determine the ultimate clinical utility.     

High signals in the uterine cervix on T2-weighted MRI sequences

The aim of this pictorial review was to illustrate the normal cervix appearance on T2-weighted images, and give a review of common or less common disorders of the uterine cervix that appear as high signal intensity lesions on T2-weighted sequences. Numerous aetiologies dominated by cervical cancer are reviewed and discussed. This gamut is obviously incomplete; however, radiologists who perform MR women's imaging should perform T2-weighted sequences in the sagittal plane regardless of the indication for pelvic MR. Those sequences will diagnose some previously unknown cervical cancers as well as many other unknown cervical or uterine lesions. Electronic Publication     

Pre-operative MR evaluation of features that indicate the need of adjuvant therapies in early stage cervical cancer patients. A single-centre experience

Objectives

This study compared the MR measurement of minimum uninvolved cervical stroma and maximum stromal invasion, and the detection of positive lymph nodes with the pathological results. In addition, tumour type and grade were correlated with nodal status and apparent diffusion coefficient (ADC) values.

Methods

Patients who underwent surgery and MR at our centre for early stage cervical cancer (FIGO IA1-IIB) were included. Data recorded included: age, date of MR, clinical FIGO (International Federation of Gynacology and Obstetrics) stage, histological type and grade, adjuvant therapy, pre-surgical conisation. MR evaluation included: measurement of the minimum uninvolved stroma, maximum thickness of stromal involvement, presence and site of positive pelvic lymph nodes, calculation of ADC values.Statistical analysis was performed to compare MR and pathological results. The agreement between MR and pathology in measuring depth of stromal invasion was analysed by Bland–Altman plot, calculating the limits of agreement (LoA).

Results

113/217 patients underwent adjuvant therapies. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of MR in evaluation of minimum thickness of uninvolved cervical stroma were 88%, 75%, 70%, 90% and 80%; the same values in evaluation of pelvic positive lymph nodes were 64%, 85%, 65%, 84% and 78%. The mean difference between MR and pathological results in measuring maximum depth of stromal invasion was −0.65 mm (95% LoA: −9.37 mm; 8.07 mm). Depth of stromal invasion was strongly related to positive nodal status (p < 0.001). ADC values (available in 51/217 patients) were not associated with the features assessed.

Conclusions

Pre-surgical MR is accurate (80%) in evaluating the minimum thickness of uninvolved cervical stroma; MR measurements of maximum depth of stromal invasion differed ±9 mm from the pathological results in 95% of cases. Furthermore, a strong association was found between the depth of stromal invasion and the presence of positive lymph nodes, suggesting that inclusion of these measurements in the MR report might guide the choice of the best treatment option for early cervical cancer patients.     

动态增强MRI在诊断颈部淋巴结病变中的价值

目的:探讨动态增强MRI(DCE-MRI)在颈部良恶性淋巴结中的诊断价值。方法:采用GE1.5T磁共振扫描仪及颈部相控阵线圈对46例单侧或双侧颈部淋巴结肿大患者行MRI平扫、动态增强MRI检查,其中26例为恶性病变,20例为良性病变,均经手术及病理证实。分析比较良恶性淋巴结病变的MRI征象,计算病灶峰值增强率Emax,峰值时间Tmax,最大强化速率Slopemax,并根据病变最高强化区ROI测量值,绘制病灶的时间-信号强度曲线(SI-Time曲线)。结果:良性淋巴结多为椭圆形,淋巴结周围水肿,脂肪边缘模糊,与周围软组织界限不清,动态强化参数Emax为(168.23±117.89)%,Tmax为(70.17±8.75)s,Slopemax为(2.96±2.03)%/s;而恶性淋巴结则呈类圆形或球形,轮廓较清晰,动态强化参数Emax为(192.74±106.84)%,Tmax为(61.92±21.37)s,Slopemax为(3.37±1.83)%/s。良、恶性淋巴结病变动态增强MRI的峰值增强率Emax、峰值时间Tmax及最大强化速率Slopemax之间的差异无显著性意义(P>0.05)。时间-信号强度曲线类型良性淋巴结病变多表现为Ⅰ型,而恶性淋巴结病变多为Ⅲ型,Ⅱ型曲线均可见于良性和恶性淋巴结病变。结论:淋巴结MRI可提供病灶的形态学及血流动力学特征,有助于良、恶性淋巴结的诊断。     

Imaging in the staging of renal cell carcinoma

Imaging is extremely important in determining the type of surgery undertaken in patients with proven renal cell carcinoma. In this review, the strength and limitation of each of the relevant techniques are outlined, highlighting particularly the correlation between the imaging findings and the pathological staging. Over the past decade, CT has become the most widely used technique for staging renal cell carcinoma, partly due to the very high overall accuracy of up to 90% that has been achieved. MRI appears to have a similar overall accuracy to CTm whereas ultrasound is less accurate than CT or MRI in th overall staging of tumours. However, ultrasound is extremely accurate in identifying and localising the clinically important tumour extension into the intra-hepatic vena cava and right atrium and if local surgical practice requres only a knowledge of venous inevasion, a technically adequate ultrasound examination may suffice. All techniques are unreliable in detecting early perinephric spread.     

Value of retrospective image fusion of F-FDG PET and MRI for preoperative staging of head and neck cancer: Comparison with PET/CT and contrast-enhanced neck MRI

Purpose

To assess the clinical value of retrospective image fusion of neck MRI and ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) PET for locoregional extension and nodal staging of neck cancer.

Materials and methods

Thirty patients with carcinoma of the oral cavity or hypopharynx underwent PET/CT and contrast-enhanced neck MRI for initial staging before surgery including primary tumor resection and neck dissection. Diagnostic performance of PET/CT, MRI, and retrospective image fusion of PET and MRI (fused PET/MRI) for assessment of the extent of the primary tumor (T stage) and metastasis to regional lymph nodes (N stage) was evaluated.

Results

Accuracy for T status was 87% for fused PET/MRI and 90% for MRI, thus proving significantly superior to PET/CT, which had an accuracy of 67% (p = 0.041 and p = 0.023, respectively). Accuracy for N status was 77% for both fused PET/MRI and PET/CT, being superior to MRI, which had an accuracy of 63%, although the difference was not significant (p = 0.13). On a per-level basis, the sensitivity, specificity and accuracy for detection of nodal metastasis were 77%, 96% and 93% for both fused PET/MRI and PET/CT, compared with 49%, 99% and 91% for MRI, respectively. The differences for sensitivity (p = 0.0026) and accuracy (p = 0.041) were significant.

Conclusion

Fused PET/MRI combining the individual advantages of MRI and PET is a valuable technique for assessment of staging neck cancer.