直肠表面线圈MRI对前列腺癌的诊断价值

目的探讨直肠表面线圈MRI对前列腺癌的鉴别诊断及分期的价值.方法 20例临床疑诊为前列腺癌的患者,分别用直肠表面线圈及体线圈进行多个轴位的TSE T1、T2及脂肪抑制序列扫描,比较两种检查方法对前列腺癌诊断及分期价值.结果直肠表面线圈MRI对前列腺癌检查的准确性(85.0%)、敏感性(85.7%)、特异性(83.3%)、阳性预测值(92.3%)均高于体线圈MRI扫描检查.结论用直肠表面线圈MRI可获得高分辨率的前列腺图像,提高对前列腺癌早期诊断率;结合体线圈,可提高对前列腺癌分期的准确性.     

Endorectal surface coil MR imaging as a staging technique for rectal carcinoma: a comparison study to rectal endosonography

Background: Preoperative staging of rectal cancer is critical for guiding therapy and prescribing the most appropriate treatment option. The purpose of this investigation was to compare the accuracy of endorectal surface coil magnetic resonance imaging (ERSCMRI) with endosonography (EUS) in staging rectal lesions. Methods: Fourteen patients with rectal carcinoma, initially detected by barium enema or sigmoidoscopy underwent ERSCMRI and EUS. Subsequent resection of the lesions was performed, and the staging accuracies of these two modalities are compared. Results: MR T-staging agreement with pathologic T-staging was similar to that of EUS, but MR enabled more accurate identification of nodal involvement. Conclusion: ERSCMRI produced greater overall accuracy in staging for rectal carcinoma than did EUS. Received: 10 September 1998/Revision accepted: 10 February 1999     

Preoperative assessment of local tumor extent in advanced rectal cancer: CT or high-resolution MRI?

Background: We compared high-resolution magnetic resonance imaging (MRI) with computed tomography (CT) in the assessment of tumor infiltration in surrounding structures for locally advanced primary and recurrent rectal cancer. Methods: Twenty-six patients with operable, locally advanced rectal cancer (15 recurrent and 11 primary) were evaluated with conventional pelvic CT and 1.5-T high-resolution MRI with a quadrature phased-array coil. The images were scored for invasion of nine neighboring pelvic structures, and the results were compared with surgical and histologic findings. Results: A total of 234 structures in 26 patients was evaluated for tumor invasion. For MRI the, sensitivity was 97% and the specificity 98%; for CT, the sensitivity was 70% and the specificity was 85%. The difference in performance was statistically significant (p < 0.001). The failure most frequently made on CT was the false-positive prediction of pelvic floor and piriform muscle invasion (14), whereas MRI showed only four false-positive predictions. MRI correctly predicted all four cases of sacral bone invasion, three of which were missed by CT. MRI was accurate in 20 patients (80%) and CT in only five patients (19%). Conclusion: High-resolution MRI using a quadrature phased-array coil is highly accurate and superior to CT in predicting tumor infiltration in surrounding structures for locally advanced primary or recurrent rectal cancer and is recommended in the preoperative work-up of these tumors. Received: 21 September 1999/Revision accepted: 26 January 2000     

TNM staging of gastrointestinal tumors by hydrosonography: results of a histopathologically controlled study in 60 patients

Background: The study is a prospective evaluation of preoperative TNM staging of gastrointestinal tumors by hydrosonography (HUS). Methods: Sixty patients with suspected gastric or colorectal cancer underwent HUS for TNM staging. All patients were operated on and the tumors completely removed when possible. HUS findings were correlated with histopathologic staging. Results: HUS correctly localized tumors in 75% of patients. T stage accuracy was low for gastric cancers (41%). N staging of gastric cancers was accurate in 68% of all cases and was highly specific (100%). Staging was more accurate for colorectal tumors (70%), especially with respect to infiltration of other structures (sensitivity 100%, specificity 95%). N staging, however, was not reliable, mostly owing to impaired examination conditions. Conclusion: HUS easily misses tumors of the gastric cardia and distal part of the rectum. T staging of colorectal tumors with HUS is highly accurate, reaching 92% if the tumor is localized. T1 cancers of the stomach tend to be overstaged, and serosal infiltration by gastric cancers is often misjudged. With the exception of cardial gastric and distal rectal cancers, HUS comes close to endosonography for staging gastrointestinal tumors. HUS does not require intraluminal access. Received: 9 May 1995/Accepted after revision: 15 August 1995     

经直肠超声与体部线圈磁共振检查对直肠癌T分期的比较研究

目的比较经直肠超声(ERUS)和体部线圈MRI对直肠癌T分期诊断准确性。方法回顾性分析31例术前未接受新辅助放化疗的直肠癌患者,对所有患者均于术前1周行ERUS和MR检查、后行一期手术切除。以术后病理结果作为金标准,比较ERUS和MRI对直肠癌T分期的诊断效能。结果 31例患者中,术后病理诊断T1期7例,T2期6例,T3期18例。ERUS显示病变累及肠管长度约(28.18±13.30)mm,MRI显示约为(35.58±18.24)mm,二者差异有统计学意义(t=3.497,P=0.002),但两种检查所测得病变下缘距肛门距离、病灶厚度的差异均无统计学意义(P均>0.05)。ERUS诊断直肠癌T1、T2、T3、T4期的准确率分别为93.55%,93.55%,87.10%和100%,总准确率为93.55%;MRI诊断直肠癌T1、T2、T3、T4期的准确率分别为87.10%,70.97%,64.52%和93.55%,总准确率为79.03%;ERUS、MRI诊断的直肠癌各期以及总准确率的差异均无统计学意义(P均>0.05)。结论 ERUS和MRI均为直肠癌术前分期诊断的可靠检查方法,ERUS对于T分期的准确性稍高于MRI。     

Detection of lymph-node metastases in patients with gastric carcinoma: comparison of three MR imaging pulse sequences

Background: To compare the diagnostic accuracy of magnetic resonance (MR) images obtained with three different pulse sequences for lymph-node metastases in patients with gastric cancer. Methods: T1-weighted spin-echo (SE), breath-hold T2-weighted fast SE, and triphasic gadolinium-enhanced dynamic gradient-recall-echo (GRE) MR images obtained in 16 patients with gastric carcinoma were retrospectively reviewed. Regional lymph nodes were assigned to four different groups, and image review was conducted on a lymph-node group-by-group basis; 64 lymph-node groups were reviewed by two radiologists. Relative sensitivity, specificity, and accuracy were determined based on the findings with definitive surgery and follow-up imaging. Diagnostic accuracy was determined by means of receiver-operating-characteristic (ROC) analysis. Results: Relative sensitivities for lymph-node metastases with T1-weighted SE, breath-hold T2-weighted fast SE, and dynamic GRE images were 61%, 94%, and 59%, respectively. Relative sensitivity with breath-hold T2-weighted fast SE images was significantly greater than that with T1-weighted SE (p < 0.05) and dynamic GRE (p < 0.05) images. Diagnostic accuracy determined by ROC analysis was marginally higher with breath-hold T2-weighted fast SE (area under ROC curve [Az]= 0.87) than with T1-weighted SE (Az = 0.78, p= 0.08) and dynamic GRE (Az = 0.79, p= 0.12) images. Conclusion: Breath-hold T2-weighted fast SE sequence is useful in the detection of regional lymph-node metastases in patients with gastric carcinoma. Received: 11 November 1998/Revision accepted: 7 April 1999     

Water Enema Transvaginal Ultrasound for Local Staging of Stenotic Rectal Carcinoma

Background: To increase the value of ultrasound in the staging of stenotic rectal carcinoma. Methods: Water enema transvaginal ultrasound (WE-TVUS) was performed in 21 consecutive female patients with severely stenotic rectal tumor (adenocarcinoma histologically proved) who were selected on the basis of clinical and double-contrast barium enema study. All patients underwent surgery, and histopathologic correlation was possible. Results: Rectal tumors were well demonstrated in all cases, and a good correlation between perirectal neoplastic infiltration, and lymph node involvement at WE-TVUS and histologic data were observed. Compared with histologic results, WE-TVUS correctly staged 19 of 21 tumors (overall accuracy = 90%); one case was understaged (T4 as T3) and one case was overstaged (T3 as T4). In the detection of lymph node involvement, the sensitivity was 50% and specificity was 78%. Conclusion: WE-TVUS is a potentially valuable technique for defining the local extension of severely stenotic rectal tumors in women. Received: 10 December 1997/Accepted: 28 January 1998     

Focal nodular hyperplasia of the liver: detection and characterization with plain and dynamic-enhanced MRI

Background: We compared nonenhanced and dynamic gadolinium (Gd)–enhanced magnetic resonance imaging (MRI) appearances of hepatic focal nodular hyperplasia (FNH) as depicted with breath-hold MR sequences and assessed the detectability of the individual MR sequences used. Methods: We retrospectively reviewed 48 consecutive patients with FNH. All patients underwent nonenhanced (T1 fast low-angle shot [FLASH] and T2 half-Fourier acquisition [HASTE]) and dynamic Gd-enhanced (T1 FLASH) MRI between December 1997 and March 2000. Individual MR sequences were analyzed separately for number of lesions, signal intensity features, dynamic enhancement pattern, and the presence and enhancement profile of a central scar. Ninety-five percent confidence intervals of absolute discrepancy were calculated to define differences in lesion detection. Results: Seventy-seven lesions were found in 48 patients. Nonenhanced FLASH imaging depicted 59 (76.6%) lesions in 45 patients. HASTE images showed 55 (71.4%) lesions in 44 patients. On T1- and T2-weighted images, lesions appeared predominantly hypointense (69.5%) and hyperintense (72.7%), respectively. Arterial and portal venous dominant phase Gd-enhanced MRI demonstrated all 77 lesions (100%), most of which showed hypervascular (94.8%), homogeneous (97.4%), and incomplete (except the central scar: 58.4%) enhancement in the arterial phase. Portal venous phase images showed lesion isointensity (50.6%) or moderate hyperintensity (46.8%) with complete enhancement (central scar: 94.8%). A central scar was detected on nonenhanced T1-weighted images (hypointense: 100%), T2-weighted images (hyperintense: 100%), arterial phase (hypointense: 59.7%) and portal venous phase (hyperintense: 71.4%) Gd-enhanced images in 78%, 69.1%, 77.9%, and 75.3% of tumors, respectively. Conclusion: Arterial and portal venous phase Gd-enhanced T1-weighted sequences are superior to nonenhanced images in the detection of FNH. Typical MRI appearances include hypointensity on T1-weighted and hyperintensity on nonenhanced T2-weighted images. Most commonly, FNH shows a homogeneous (without scar) and strong enhancement during the arterial phase, with lesion isointensity or slight hyperintensity during the portal venous phase. Received: 15 May 2001/Revision accepted: 22 August 2001     

Cervical carcinoma: efficacy of thin-section oblique axial T2-weighted images for evaluating parametrial invasion

Background: To investigate the efficacy of thin-section oblique axial T2-weighted images in the assessment of parametrial invasion by cervical carcinoma. Methods: One hundred parametria of 50 patients with cervical carcinoma were evaluated with pathologic correlation. We compared the sensitivity, specificity, and diagnostic accuracy in the assessment of parametrial invasion by cervical carcinoma between axial T2-weighted images and thin-section oblique axial T2-weighted images. Results: Thin-section oblique axial T2-weighted images provided accurate cross sections of the cervix with excellent detail and detected parametrial invasion more accurately than did axial T2-weighted images showing cross sections of the trunk. Although the sensitivity, specificity, and accuracy for parametrial invasion were 46.4%, 91.7%, and 79.0%, respectively, on axial T2-weighted images, the corresponding values were 67.9%, 97.2%, and 89.0%, respectively, on thin-section oblique axial T2-weighted images. There were statistically significant differences in the sensitivity (p = 0.014), specificity (p = 0.046), and accuracy (p = 0.002) in detecting parametrial invasion between these two types of images. Conclusions: Thin-section oblique axial T2-weighted images are useful for the assessment of parametrial invasion by cervical carcinoma. Received: 11 September 1998/Accepted: 2 December 1998     

Evaluation of Crohn disease activity with magnetic resonance imaging

Background: The purpose of this study was to assess the accuracy of magnetic resonance imaging (MRI) in evaluating Crohn disease (CD) activity. The intestinal inflammatory activity is usually present in patients under pharmacologic treatment, despite their clinical remission. Methods: Twenty patients with CD, all under pharmacologic treatment, were prospectively studied by MRI at 1.5 T as a periodic control. Positivity of three acute-phase reactants was considered an index of biologic activity (BA). T2-weighted, T2-weighted fat-suppressed turbo spin-echo, and breath-hold T1-weighted turbo field-echo sequences, before and after gadolinium intravenous injection, were obtained. A negative superparamagnetic contrast agent was orally administered. The following MRI parameters were qualitatively evaluated by three radiologists at the level of the affected bowel and compared with clinical data: wall thickness (WT), wall T2-weighted signal (T2W), wall contrast enhancement (WE), amount of fibrofatty proliferation (FP), and T2-weighted signal of fibrofatty proliferation on fat-suppressed images (T2FP). The κ coefficient of agreement was calculated. The Spearman rank correlation was used for the analysis of clinical and radiologic data. Results: Nineteen of 20 patients were in clinical remission (Crohn Disease Activity Index < 150). On the basis of laboratory tests, nine of 20 patients had biologically active disease. An excellent correlation was found between BA and WE, T2W, and T2FP (0.900, 0.927 and 0.961, respectively; p < 0.0001), and a lower correlation was found between BA and WT and between BA and FP (0.78 and 0.62). Excellent statistical correlation was also found between WE and T2W and between WE and T2FP (0.876 and 0.892). Conclusions: An excellent statistical correlation was found between biologically “active” disease and the following MRI parameters: wall gadolinium enhancement, wall hyperintensity on T2-weighted fat-suppressed images, and hyperintensity of fibrofatty proliferation on T2-weighted fat-suppressed images. Therefore, MRI can be valuable in assessing CD activity. Received: 22 January 1999/Revision accepted: 3 November 1999     

Fan-shaped hepatic parenchymal damage after ethanol injection therapy for hepatocellular carcinoma: MRI appearances

Background: T1- and T2-weighted magnetic resonance (MR) images frequently show fan-shaped areas of hypo- or hyperintensity in the hepatic parenchyma adjacent to a treated hepatocellular carcinoma after percutaneous ethanol injection (PEI) therapy. These areas correspond to abnormal contrast enhancement on serial dynamic MR images. The purpose of the present study was to describe the location, appearance, and frequency of these abnormalities because it is important to understand these entities for the correct assessment of therapeutic efficacy. Methods: MR imaging including a multisection dynamic study was performed in 20 consecutive patients with hepatocellular carcinoma treated with PEI therapy. We retrospectively evaluated the presence of fan-shaped hypointensities adjacent to treated tumors in the liver parenchyma on T1-weighted images and hyperintensities on T2-weighted images and corresponding fan-shaped contrast enhancement on both arterial-dominant and delayed-phase dynamic MR images. We review the location, appearance, and frequency of these findings, and we discuss the possible causes on the basis of pathologic examinations. Results: Seven (35%) of the 20 patients showed fan-shaped hyperintense areas adjacent to the treated tumors on T2-weighted images. These areas showed isointensity in five patients and hypointensity in two patients on T1-weighted images. Of these seven patients, one (14%) underwent the MR imaging within 1 month after the completion of PEI therapy, and six (86%) had it 2–9 months after the completion of PEI therapy (mean = 6 months). In all seven patients, fan-shaped hyperperfusion abnormalities corresponding to these areas of hyperintensity on T2-weighted images were seen on both arterial-dominant and delayed-phase dynamic MR images. Pathologically, the coagulative necrosis of the hepatocytes with sinusoidal dilatation and the restoration by the development of fibrous tissue were seen in these fan-shaped areas. Conclusion: The fan-shaped areas of abnormal intensity on T1- and T2-weighted images and contrast enhancement on dynamic MR images seem to be attributable to pathologic changes in the normal liver parenchyma induced by the toxic reaction of ethanol. Awareness of the occurrence of such abnormalities in the peripheral liver parenchyma adjacent to the treated tumor is important for the correct assessment of therapeutic efficacy. RID="ID="<e5>Correspondence to:</e5> T. Fujita Received: 24 June 1997/Accepted after revision: 22 October 1997     

High resolution MRI of anorectal malformation in the newborn: case reports of Currarino syndrome and anocutaneous fistula

To show the accuracy of a high-resolution magnetic resonance imaging (MRI) technique with a phased array coil in diagnosing anorectal malformation, we present two neonates with Currarino syndrome and anocutaneous fistula, respectively. Anatomy was visualized correctly with this technique, but conventional MRI did not show the complete extent of the disease. The reported high-resolution MRI findings concerning these conditions are scanty. Received: 26 March 2001/Accepted: 2 May 2001     

MRI of recurrent rectosigmoid carcinoma

Background: A prospective study was performed to determine the most reliable MRI criteria to distinguish recurrent rectosigmoid carcinoma from benign postoperative fibrosis. Methods: Twenty-two consecutive patients who were suspected to have recurrent rectosigmoid carcinoma were examined by T2 and precontrast and contrast enhanced T1 weighted images. The prospective interpretations, the presence of high signal on T2 weighted images, the shape of the margins of a mass and the degree of contrast enhancement were correlated with histology and follow up to determine their respective accuracies, sensitivities and specificities. Results: The best criteria for recurrent tumor was the combination of high signal on T2 weighted images, round margins and > 40% contrast enhancement, which had an accuracy of 92%, sensitivity of 100% and specificity of 85%. In patients who were more than one year postoperative the specificity was 100%. Conclusions: The most reliable MRI criteria for distinguishing recurrent rectosigmoid carcinoma from benign postoperative fibrosis are the combination of the signal intensity on T2 weighed images, the shape of the margins of a mass and the presence of greater than 40% contrast enhancement. Received: 6 February 1996/Accepted after revision: 19 June 1996     

MRI相控阵线圈在直肠癌术前分期中的应用价值

目的 探讨MRI相控阵线圈在直肠癌术前分期中的应用价值.方法 43例经病理证实的直肠癌患者,术前应用MRI体表相控阵线圈检查.将术前MRIT分期结果及淋巴结转移诊断与术后病理组织学对照.结果 43例直肠癌病例术前T分期诊断准确率81.4%.诊断淋巴结转移的准确率83.7%.敏感度78.9%,特异度87.5%.转移性淋巴结在T2WI上表现为混杂信号,边缘形态不规则.结论 MRI体表相控阵线圈检查对于直肠癌T分期有着较高的诊断准确率,转移性淋巴结在MRI上具有一定特异性征象,MRI相控阵线圈在直肠癌术前分期中有较高的临床价值.     

Contribution of the MR spectroscopic imaging in the diagnosis of prostate cancer in the peripheral zone

Purpose To establish the additional value of 3D magnetic resonance spectroscopy (3D-MRS) imaging to endorectal MR imaging in the diagnosis of prostrate cancer in the peripheral zone. Materials and methods MR imaging and MRS imaging were performed in 79 patients with suspicion of prostate cancer on the basis of digital rectal exploration, transrectal ultrasound and PSA level. All the examinations were performed with 1.5 T MR scan using an endorectal coil (transverse and coronal FSE T2-weighted sequences, axial SE T1-weighted and PRESS 3D CSI). MR examinations have been evaluated by two Radiologists blind of the clinical data in a “per patients” analysis. MR imaging and MRS imaging findings were compared with the result of histological data from radical prostatectomy in 53 patients and biopsy in 17 patients. Results Nine patients (11.4%) were excluded because of serious artefacts in the MR spectrum. The reported values of sensitivity, specificity, PPV and NPV for MR imaging alone were respectively 84%, 50%, 76% and 63% (LR+ 1.7; LR− 0.3). Instead the reported values of sensitivity, specificity, PPV and NPV for the combination of MR imaging to MRS imaging were respectively 89%, 79%, 89% and 79% (LR+ 4.28; LR− 0.14). We found an incremental benefit of MRS imaging to MR imaging for tumour diagnosis although these results did not show statistically significant differences. Conclusions The MRS imaging improves the accuracy of the endorectal MR imaging in the diagnosis of prostate cancer.     

Hepatic MR imaging: comparison of RARE derived sequences with conventional sequences for detection and characterization of focal liver lesions

Background: We compared two T2-weighted turbo spin echo (TSE) sequences with a T2-weighted conventional SE (CSE) sequence to determine whether sequences derived from rapid acquisition with relaxation enhancement such as TSE could replace CSE for the detection and subsequent characterization of focal liver lesions. Methods: A total of 55 consecutive patients with 107 liver lesions underwent magnetic resonance imaging examinations at 1.5 Tesla, with a constant imaging protocol. TSE pulse sequences were acquired with eight echo trains (repetition time [TR], 4718 ms; echo time [TE], 90 ms; acquisition time [TA], 4.03 min; and a symmetric k-space ordering scheme) and 11 echo trains (TR, 4200 ms; TE, 140 ms; TA, 4.40 min; and an asymmetric k-space ordering scheme) and compared with CSE (TR, 2300 ms; TE, 45/90 ms; TA, 9.53 min). Images were analyzed qualitatively by scoring image quality and artifacts and counting focal liver lesions by independent reading with consensus obtained for discrepancies. Quantitative analysis was performed by measuring signal-to-noise (S/N), contrast-to-noise (C/N), and tumor–liver signal intensity (T/L) ratios. Results: T2-weighted TSE sequences provided better subjective image quality and reduced artifacts as compared with the T2-weighted CSE sequence. CSE and TSE sequences exhibited no statistically significant differences in liver S/N, lesion–liver C/N (CSE TE, 90 ms: 18.6 ± 14.0; TSE TE, 90 ms: 16.5 ± 12.9) and the detectability of focal liver lesions. Heavily T2-weighted TSE with a TE of 140 ms allowed correct characterization of focal liver lesions based on a T/L ratio of 3.0 in 84% of patients. Conclusions: T2-weighted TSE sequences are as suited as CSE for the detection (TE, 90 ms), and appear to be superior for the characterization (TE, 140 ms), of focal hepatic lesions. Whether a single sequence, such as a double-echo TSE or a single-echo TSE sequence with a TE between 110 and 120 ms, might perform both functions as well or better than CSE is unknown. However, because of time savings, TSE eventually may be preferred over CSE. Received: 13 December 1994/Accepted after revision: 31 March 1995     

Percutaneous MR imaging-guided laser-induced thermotherapy of hepatic metastases

Background: Many primary tumors may cause liver metastases, which are generally treated with surgical resection and/or chemotherapy. After resection of liver metastases in patients with colorectal carcinoma, 5-year survival rates are achieved in 25–38%, and two-thirds of patients will experience recurrent metastases. We examined percutaneous, minimally invasive, laser-induced thermotherapy (LITT) as an alternative outpatient procedure. Local tumor control rate and survival data were analyzed prospectively. Methods: Between June 1993 and August 2000, 7148 laser applications were performed in 1981 lesions in 705 consecutive patients and 1653 treatment sessions. The complications of the procedure were evaluated by clinical examination and magnetic resonance imaging (MRI) and computed tomography. Local tumor control was evaluated by plain and contrast-enhanced follow-up MRI using T1- and T2-weighted spin-echo and gradient-echo sequences every 3 months after treatment. Cumulative survival times were calculated using the Kaplan–Meier method. Results: The overall rate of complications and side effects was 7.5%. The rate of clinically relevant complications was 1.3%. Local tumor control rate after 3 months was 99.3%; 6 months after laser treatment, plain and contrast-enhanced MRI documented a local tumor control rate of 97.9%. In patients treated with MR-guided LITT for unresectable colorectal liver metastases, the mean survival was 41.8 months (95% confidence interval = 37.3–46.4 months). The 1-year survival rate was 93%, the 2-year survival rate was 74%, the 3-year survival rate was 50%, and the 5-year survival was 30%. In patients treated with LITT for liver metastases from breast cancer, the mean survival was 4.3 years (95% confidence interval = 3.6–5.0 years). Conclusion: In patients with liver metastases, local tumor destruction using minimally invasive, percutaneous LITT under local anesthesia results in improved clinical outcomes and survival rates and can be a potential alternative to surgical resection.     

Well-differentiated hepatocellular carcinoma: findings of US, CT, and MR imaging

Background: To elucidate the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs) on ultrasonography (US), computed tomography (CT), and magnetic resonance (MR) imaging. Methods: Ultrasonograms, CTs, and MR images of 18 histopathologically proven well-differentiated HCCs in 15 patients were reviewed. The findings of these images were correlated with histopathologic findings. Results: On US, seven tumors were depicted as a hyperechoic area and eight as a hypoechoic area. Three tumors were not visualized. On precontrast CT, four tumors were depicted as a low-density area, but 14 were not visualized. On conventional contrast-enhanced CT, 12 tumors were depicted as a low-density area but six were not visualized. On T1-weighted MR images, 10 tumors had high signal intensity and two had low signal intensity. Six tumors were not visualized. On T2-weighted MR images, five tumors had high signal intensity and two had low signal intensity. Eleven tumors were not visualized. Tumors with fatty change and/or clear cell formation were frequently hyperechoic on US and hyperintense on T1-weighted MR images. Conclusions: Well-differentiated HCCs show different findings on US, CT, and MR imaging. Therefore, reliable diagnosis of well-differentiated HCCs by these imaging techniques may be difficult. Received: 29 April 1998/Revision accepted: 15 July 1998     

MRI在直肠癌诊疗中的发展过程与应用

直肠癌是胃肠道常见的恶性肿瘤之一,其治疗与预后主要取决于分期。目前对直肠癌分期最为准确的检查方法是MRI。初期,MRI常规序列对直肠癌的T、N分期准确率偏低,为了提高诊断准确性、为临床提供更多的信息,学者们运用了直肠腔内线圈,局部高分辨T2WI序列,增强及动态增强(dynamic contrast enhancement,DCE)扫描以及扩散加权成像(diffusion-weighted imaging,DWI)序列等进行扫描。作者就上述MRI新序列或技术的临床应用及其意义展开综述。     

Fascioliasis: US, CT, and MRI findings with new observations

Background: The purpose of this study is to describe the ultrasonographic (US), computed tomographic (CT), and magnetic resonance imaging (MRI) findings in fascioliasis and to emphasize the impact of radiology in diagnosis. Methods: Radiologic findings in 23 consecutive patients with fascioliasis were prospectively recorded. All patients had at least one US and CT examination, and 10 of them were studied by MRI. All diagnoses were confirmed by serologic methods. In the first three cases, initial diagnosis was reached by microscopic demonstration of the parasites' eggs in bile obtained by US-guided gallbladder aspiration. Results: In the hepatic phase of fascioliasis, multiple, confluent, linear, tractlike, hypodense, nonenhancing hepatic lesions were detected by CT. On US, the parasites could be clearly identified in the gallbladder or common bile duct as floating and nonshadowing echogenic particles. MRI showed the lesions as hypo- or isointense on T1-weighted images and as hyperintense on T2-weighted images. Conclusions: CT findings in the hepatic phase and US findings in the biliary phase are characteristic of fascioliasis. Because clinical and laboratory findings of fascioliasis may easily be confused with several diseases, radiologists should be familiar with the specific radiologic findings of the disease to shorten the usual long-lasting diagnostic process. Received: 15 December 1999/Accepted: 26 January 2000