肛管内超声及MRI对肛门癌的分期、疗效评价及随访的价值

肛门癌是严重的但少见的专科疾病。肛管内超声、MRI可用于肛门癌病人局部分期及随访观察,有助于指导治疗方案及预后。近来,欧洲临床肿瘤协会发布的指南推荐MRI作为评价局部病灶的检查方法。本研究介绍了肛管内超声和MRI技术,并对肛门癌局部评估的优缺点进行比较。     

Lung cancer staging: the role of computed tomography and magnetic resonance imaging

Because complete resection remains the only reliable method of cure of lung cancer, one important aim of preoperative staging is to select patients with localised disease who may benefit from surgery, while avoiding unnecessary thoracotomies in patients with unresectable neoplasm. Computed tomography (CT) of the chest is a valuable method for staging local and regional spread of lung neoplasms, although limitations in its accuracy are well-known. While gross invasion of the mediastinum and major structures as well as the presence of metastatic disease can be easily demonstrated with CT, differentiation between tumour contiguity and subtle invasion of mediastinum or chest wall often remains a problem. Although magnetic resonance imagaing (MRI) may have the same limitations as CT, in specific situations it may b superior in diagnosing minimal chest wall or mediastinal invasion. Moreover, MRI is useful in the assessment of patients with superior sulcus tumours as well as in patients with contraindication to intravenous administration of ionic contrast material. Since nodal size is the only useful criterion for evaluating lymph node metastases, CT and MRI show similar, poor accuracies in lymph node staging reesulting from both low sensitivity (normal-sized nodes may contain microscopic metastases) and low specificity (enlarged lymph nodes may be reactive). For this reason, if enlarged lymph nodes are detected, further evaluation is recommended before excluding the patient from a potentially curative resection. Advantages and limitations of CT and MRI in the preoperative staging of non-small-cell carcinoma are reviewed in this article. The imaging of small-cell carcinoma is not included because most patients with this cell type do not benefit from surgical resection. Similarly we do not discuss imaging of distant metastases.     

Comparison of magnetic resonance imaging with computed tomography and intravesical ultrasound in staging bladder cancer

Magnetic resonance imaging (MRI), computed tomography (CT), and intravesical ultrasound (US) scanning were performed on 11 patients in whom infiltrative bladder cancer was suspected at cystoscopy. Equipment with magnetic field 0.02 T was used for the MRI. Tumors larger than 2 cm could be identified in all cases by MRI. In 3 of 4 cases in which the tumor was smaller than 2 cm, it could not be properly visualized and the degree of infiltration could not be assessed. When the tumor was visualized on MRI, tumor staging by MRI was correct in 7 of 8 cases (88%). Infiltration of the deep muscle layer of the bladder wall could be detected by MRI but not by CT. Intravesical US staging was correct in 7 of 9 cases (78%). As a noninvasive method, MRI is promising for the preoperative evaluation of bladder cancer and offers the advantage of imaging the bladder in different planes.     

Comparison of magnetic resonance imaging with computed tomography and intravesical ultrasound in staging bladder cancer

Magnetic resonance imaging (MRI), computed tomography (CT), and intravesical ultrasound (US) scanning were performed on 11 patients in whom infiltrative bladder cancer was suspected at cystoscopy. Equipment with magnetic field 0.02 T was used for the MRI. Tumors larger than 2 cm could be identified in all cases by MRI. In 3 of 4 cases in which the tumor was smaller than 2 cm, it could not be properly visualized and the degree of infiltration could not be assessed. When the tumor was visualized on MRI, tumor staging by MRI was correct in 7 of 8 cases (88%). Infiltration of the deep muscle layer of the bladder wall could be detected by MRI but not by CT. Intravesical US staging was correct in 7 of9 cases (78%). As a noninvasive method, MRI is promising for the preoperative evaluation of bladder cancer and offers the advantage of imaging the bladder in different planes.     

The role of ultrasound and magnetic resonance imaging in the evaluation of the forearm interosseous membrane. A review

The interosseous membrane of the forearm is an important structure to consider in cases of elbow and forearm trauma; it can be injured after elbow or forearm fractures, leading to longitudinal forearm instability. Diagnosis of interosseous membrane injuries is challenging, and failure in diagnosis may result in poor clinical outcomes and complications. Magnetic resonance imaging and ultrasound have shown to be valuable methods for the evaluation of this important structure. Both techniques have advantages and limitations, and its use should be adapted to each specific clinical scenario. This article presents an up-to-date literature review regarding the use of ultrasound and magnetic resonance imaging in the forearm interosseous membrane evaluation.     

Uterine cervix cancers: staging by magnetic resonance imaging

The accuracy of Magnetic Resonance Imaging in cervical carcinoma staging for clinical stages superior to IB was studied retrospectively in 27 patients. The MRI results were then correlated with operative findings in 12 cases and with examination carried out under general anesthesia in 15 cases for myometrial, bladder, rectal, parametrial, parietal and vaginal extension. The accuracy of MRI was 81.5% for bladder, 92.5% for rectal, 87% for parametrial and 73% for vaginal extension. The accuracy of staging by MRI was 59%. The contribution of MRI in pre-operative studies for cervical carcinomas has not been properly defined until now. Nevertheless it is a particularly valuable technique due to its non invasive nature.     

The role of magnetic resonance imaging and ultrasound in patients with adnexal masses

AIMS: To evaluate the accuracy of ultrasonography (US) and magnetic resonance imaging (MRI) in characterizing adnexal masses, and to determine which patients may benefit from MRI. METHODS: We prospectively studied 72 women (mean age 53 years, range 19 to 86 years) with clinically suspected adnexal masses. A single experienced sonographer performed transabdominal and transvaginal greyscale spectral and colour Doppler examinations. MRI was carried out on a 1.5T system using T1, T2 and fat-suppressed T1-weighted sequences before and after intravenous injection of gadolinium. The adnexal masses were categorized as benign or malignant without knowledge of clinical details, according to the imaging features which were compared with the surgical and pathological findings. RESULTS: For characterizing lesions as malignant, the sensitivity, specificity and accuracy of MRI were 96.6%, 83.7% and 88.9%, respectively, and of US were 100%, 39.5% and 63.9%, respectively. MRI was more specific (p<0.05) than US. Both MRI and US correctly diagnosed 17 (24%) cases with benign and 28 (39%) cases with malignant masses. MRI correctly diagnosed 19 (26%) cases with benign lesion(s), which on US were thought to be malignant. The age, menopausal status and CA-125 levels in these women made benign disease likely, but US features were suggestive of malignancy (large masses and solid-cystic lesions with nodules). CONCLUSION: MRI is more specific and accurate than US and Doppler assessment for characterizing adnexal masses. Women who clinically have a relatively low risk of malignancy but who have complex sonographic features may benefit from MRI.     

Identification and staging of pancreatic tumours using computed tomography, endoscopic ultrasound and mangafodipir trisodium-enhanced magnetic resonance imaging

Pancreatic malignancy can be staged by a number of different investigations, either alone or in combination. The purpose of the present study was to compare the use of endoscopic ultrasound, CT and mangafodipir trisodium-enhanced MRI for the staging of pancreatic malignancy, particularly with respect to determining resectability prior to surgery. Twenty-seven patients referred for the investigation of a suspected pancreatic malignancy were entered into the trial. All patients had contrast-enhanced CT, gadolinium and mangafodipir trisodium-enhanced MRI, and endoscopic ultrasound (EUS). Images were assessed for nodal staging, tumour staging and resectability for each investigation, and the results compared with findings at surgery. The results for the accuracy of MRI, CT and EUS, in detecting T4 disease versus T3 or lower was 78, 79 and 68%, respectively; nodal involvement was 56, 63 and 69%, respectively; and overall resectability (including the T stage, presence of involved nodes and metastases) was 83, 76 and 63%, respectively. There was no significant difference demonstrated between the three tests. The present study suggests that for patients referred for investigation and staging of pancreatic malignancy, EUS and MRI scanning convey little advantage over contrast-enhanced CT. Furthermore, although mangafodipir trisodium improved the conspicuity of pancreatic tumours, it has little influence on T staging.     

The role of magnetic resonance imaging in the evaluation of Ewing sarcoma

The experience with magnetic resonance imaging (MRI) in 27 patients with Ewing sarcoma is reported and compared with computed tomography (CT) and plain films. Plain radiography proved to be the best imaging method to asses probable histological diagnosis in all cases (n=6). For the evaluation of chemotherapeutic response (n=4), CT and MRI gave the same information about the variation in size of the tumor. In this small series, the high signal in T2 weighted images was not altered significantly by therapy. In preoperative evaluation (n=14), MRI gave better information than CT of soft tissue involvement and extension within the bone marrow in two cases each. The ability of MRI to accurately define extension through the epiphyseal plate in two cases permitted limb salvage which otherwise would not have been possible. In the long-term follow-up (n=12), three patients without recurrence one year after therapy showed a low signal in the surgical area in T2 weighted images. Nine patients had a high signal in T2 weighted images: four were reactive lesions, two had obvious recurrence, and one was a hematoma. In the two remaining cases plain films and CT were normal, in the presence of both active tumor and reactive lesions. It was not possible with MRI to differentiate active tumor from reactive change, even after Gd-DTPA infusion.     

Subungual keratoacanthoma: ultrasound and magnetic resonance imaging findings

Subungual keratoacanthoma is a rare, squamoproliferative neoplasm arising at the nail bed. It may cause erosion of the underlying bone. We report a case of subungual keratoacanthoma of the right thumb in a 63-year-old man. Radiographs showed cortical erosion of the distal phalanx of the right thumb. Ultrasonography showed a mixed echoic tumor. On magnetic resonance imaging (MRI), the tumor showed intermediate signal intensity on T1-weighted images and mixed intermediate and high signal intensity on T2-weighted images with peripheral thin rim enhancement.     

High-resolution magnetic resonance imaging of the anal sphincter using a dedicated endoanal receiver coil

The use of a surface coil in MR imaging improves signal-to-noise ratio of adjacent tissues of interest. We therefore devised an endoanal receiver coil for imaging the anal sphincter. The probe is solid and re-usable: it comprises a saddle geometry receiver with integral tuning, matching and decoupling. It is placed in the anal canal and immobilised externally. Both in vitro and in vivo normal anatomy is identified. The mucosa is high signal intensity, the submucosa low signal intensity, the internal sphincter uniformly high signal intensity and the external sphincter low signal intensity on T1- and T2-weighted images. In females, the transverse perineal muscle bridges the inferior part of the external sphincter anteriorly. In perianal sepsis, collections and the site of the endoanal opening are identified. In early-onset fecal incontinence following obstetric trauma/surgery, focal sphincter defects are demonstrated; in late-onset fecal incontinence external sphincter atrophy is seen. In fecally incontinent patients with scleroderma, forward deviation of the anterior sphincter musculature with descent of rectal air and feces into the anal canal is noted. The extent of sphincter invasion is assessed in low rectal tumours. In children with congenital anorectal anomalies, abnormalities of the muscle components are defined using smaller-diameter coils. Such information is invaluable in the assessment and surgical planning of patients with a variety of anorectal pathologies. Received: 17 March 1998; Revision received: 19 May 1998; Accepted: 27 May 1998     

Pericardial lipoma: ultrasound, computed tomography and magnetic resonance imaging findings

Primary tumours of the heart and pericardium are extremely rare. Cardiac lipomas account for only 10% of all primary cardiac tumours. A case of surgically proven pericardial lipoma demonstrated by ultrasound, CT and MRI is presented here.     

Pilomatricoma: magnetic resonance imaging and pathological evaluation

Pilomatricoma is an asymptomatic, slowly growing, benign skin tumor that is typically located in the regions of head and neck. We present 1 case of pilomatricoma studied with dynamic magnetic resonance imaging and bone scintigraphy. Our case revealed late enhancement in the dynamic magnetic resonance imaging study that is a common pattern more in a benign soft tissue tumor and caused dramatic uptake in the bone scintigraphy. These findings are not ever reported in published articles. Surgical excision of the lesions was performed, and the pathological evaluation revealed a pilomatricoma.     

磁共振成像对冈上肌腱损伤分级的评估效能

目的：探讨磁共振成像对冈上肌腱损伤分级的评估效能。方法回顾性分析84例肩部疼痛患者的临床症状、肩关节磁共振扫描方法以及影像表现。结果磁共振斜冠状位诊断冈上肌腱损伤1级40例,2级28例,3级16例;横断位1级59例,2级10例,3级15例;斜矢状位1级65例,2级9例,3级10例。斜冠状位质子压脂序列显示冈上肌腱损伤磁共振分级与临床诊断符合率最高。结论肩关节磁共振扫描能清晰显示冈上肌腱损伤的范围、程度,并进行分级,对临床治疗方法的选择有重要帮助。     

Accuracy in staging carcinoma of the bladder by magnetic resonance imaging

Thirty-four patients with a presumptive diagnosis of carcinoma of the bladder diagnosed at EUA and cystoscopy have been staged by MRI and the findings correlated with pathology in 15 patients and clinical follow-up, including repeat cystoscopy, in the remainder. MRI is accurate in identifying tumours confined to the bladder wall or extending beyond the wall to involve perivesical fat or adjacent organs. Whilst it is not possible to distinguish between T1, T2 or early T3a tumours they can be distinguished from advanced T3a lesions and this may affect management. MRI is superior to clinical staging, particularly in detecting lymphadenopathy and provides information for optimal radiotherapy planning. The problem of distinguishing between the effects of radiotherapy and suspected recurrent tumour is discussed.     

Comparison of the digital rectal examination, endorectal ultrasound, and body coil magnetic resonance imaging in the staging of adenocarcinoma of the prostate

A series of 25 patients with biopsy proven adenocarcinoma of the prostate underwent preoperative staging evaluation with a digital rectal examination, endorectal ultrasound, and body coil magnetic resonance imaging (MRI) before their radical retropubic prostatectomy. The sensitivity and specificity of the digital rectal examination for the detection of extracapsular disease were 17 and 100%, respectively. The sensitivity and specificity of endorectal ultrasound for the detection of extracapsular disease were 35 and 89%, respectively. The sensitivity and specificity of body coil MRI for the detection of extracapsular disease by adenocarcinoma of the prostate were 47 and 63%, respectively. Microscopic disease of the capsule and seminal vesicles was the principle reason for understaging by both imaging modalities. This small series suggests that both imaging modalities are marginally more sensitive, albeit less specific, for extracapsular disease of the prostate than the digital rectal examination, with ultrasound having a slight edge in specificity and MRI having a slight edge in sensitivity.     

Comparison of the digital rectal examination,endorectal ultrasound,and body coil magnetic resonance imaging in the staging of adenocarcinoma of the prostate

A series of 25 patients with biopsy proven adenocarcinoma of the prostate underwent preoperative staging evaluation with a digital rectal examination, endorectal ultrasound, and body coil magnetic resonance imaging (MRI) before their radical retropubic prostatectomy. The sensitivity and specificity of the digital rectal examination for the detection of extracapsular disease were 17 and 100%, respectively. The sensitivity and specificity of endorectal ultrasound for the detection of extracapsular disease were 35 and 89%, respectively. The sensitivity and specificity of body coil MRI for the detection of extracapsular disease by adenocarcinoma of the prostate were 47 and 63%, respectively. Microscopic disease of the capsule and seminal vesicles was the principle reason for understaging by both imaging modalities. This small series suggests that both imaging modalities are marginally more sensitive, albeit less specific, for extracapsular disease of the prostate than the digital rectal examination, with ultrasound having a slight edge in specificity and MRI having a slight edge in sensitivity.     

MR对声门上型喉癌分期的价值

目的：探讨MR对声门上型喉癌术前T分期的准确性，为治疗方案选择提供影像学依据。方法：对手术切除的48例声门上型喉癌的MR资料进行分析，观察肿瘤侵犯范围及有无颈淋巴结转移，按双盲法根据MR表现进行T分期并与手术病理结果进行对比。结果：NR术前肿瘤T分期的准确性为89．5％(43／48)，判断肿瘤侵犯周围结构的准确性在85％～100％之间，诊断颈部淋巴结的准确性为89％(24／27)。结论：MR能准确判断肿瘤的侵犯范围，准确判断有无淋巴结的转移，对临床治疗方案的选择具有重要意义。