Early gastric carcinoma: evaluation with high-spatial-resolution MR imaging in vitro.

PURPOSE: To determine signal intensity characteristics of the gastric wall layers and to assess the accuracy of the evaluation of early gastric carcinomas in vitro by using resected specimens studied with high-spatial-resolution magnetic resonance (MR) imaging. MATERIALS AND METHODS: Fifteen gastric specimens obtained from patients suspected of having early gastric carcinoma were studied with a 1.5-T MR system with a 4-cm-diameter loop coil. High-spatial-resolution spin-echo MR images were obtained with a field of view of 50 mm, a matrix of 256 x 256, and a section thickness of 2 mm, resulting in a voxel size of 0.08 mm(3). Findings from MR images were compared with histopathologic findings. RESULTS: T1- and T2-weighted MR images clearly depicted the normal gastric wall as consisting of four and six layers, respectively, which corresponded well to the histologic layers. In 14 (93%) of 15 gastric carcinomas, the depth of mural invasion visualized with MR imaging correlated well with the histopathologic stage. The stage determined with MR imaging, however, was lower in one instance (7%) than the histopathologic stage. MR imaging also depicted the gross features of the tumor, presence of ulceration, and adjacent lymph node swelling. CONCLUSION: High-spatial-resolution MR imaging has a high diagnostic accuracy in the evaluation of the mural invasion of early gastric carcinoma in vitro and thus potentially enables preoperative histopathologic staging.     

Prostate cancer: accurate determination of extracapsular extension with high-spatial-resolution dynamic contrast-enhanced and T2-weighted MR imaging--initial results

PURPOSE: To prospectively compare the sensitivity and specificity of high-spatial-resolution dynamic contrast material-enhanced magnetic resonance (MR) imaging with those of high-spatial-resolution T2-weighted MR imaging, performed with an endorectal coil (ERC), for assessment of extracapsular extension (ECE) and staging in patients with prostate cancer, with histopathologic findings as reference. MATERIALS AND METHODS: The study was approved by the institutional internal review board; a signed informed consent was obtained. MR imaging of the prostate at 1.5 T was performed with combined surface coils and ERCs in 32 patients (mean age, 65 years; range, 42-78 years) before radical prostatectomy. High-spatial-resolution T2-weighted fast spin-echo and high-spatial-resolution dynamic contrast-enhanced three-dimensional gradient-echo images were acquired with gadopentetate dimeglumine. Dynamic contrast-enhanced MR images were analyzed with a computer-generated color-coded scheme. Two experienced readers independently assessed ECE and tumor stage. MR imaging-based staging results were compared with histopathologic results. For the prediction of ECE, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Staging accuracy was determined with the area under the receiver operating characteristic curve (AUC) by using the Wilcoxon-Mann-Whitney index of diagnostic accuracy. RESULTS: The mean sensitivity, specificity, PPV, and NPV for assessment of ECE with the combined data sets for both readers were 86%, 95%, 90%, and 93%, respectively. The sensitivity of MR images for determination of ECE was significantly improved for both readers (>25%) with combined data sets compared with T2-weighted MR images alone. The combined data sets had a mean overall staging accuracy for both readers of 95%, as determined with AUC. Staging results for both readers were significantly improved (P<.05) with the combined data sets compared with T2-weighted MR images alone. CONCLUSION: The combination of high-spatial-resolution dynamic contrast-enhanced MR imaging and T2-weighted MR imaging yields improved assessment of ECE and better results for prostate cancer staging compared with either technique independently.     

Scaphoid fractures: evaluation with high-spatial-resolution US initial results.

PURPOSE: To evaluate the diagnostic accuracy of high-spatial-resolution ultrasonography (US) in the diagnosis of scaphoid fractures. MATERIALS AND METHODS: In 72 hours after acute wrist trauma, 15 consecutive patients were examined for possible scaphoid fractures clinically and with conventional radiographs, including scaphoid views. Thereafter, high-spatial-resolution US was performed by two experienced radiologists blinded to the results of the previously performed investigations. High-spatial-resolution US of the scaphoid bones was performed from the palmar, lateral, and dorsal directions in the longitudinal and transverse planes. US findings indicative of a scaphoid fracture were cortical discontinuity and/or periosteal elevation. Finally, magnetic resonance (MR) images (short inversion time inversion-recovery, T1- and T2*-weighted) (ie, the standard) of the affected wrist were obtained and evaluated for a possible scaphoid fracture by two radiologists in consensus. RESULTS: Nine of 15 patients had scaphoid fractures. Seven (78%) of nine patients had positive findings at high-spatial-resolution US and five (56%) had such findings at conventional radiography (ie, four occult scaphoid fractures), with an accuracy of 87% and 73%, respectively. Two (50%) of four radiographically occult scaphoid fractures were depicted with high-spatial-resolution US. Sonographic findings of scaphoid fractures were either cortical discontinuity (n = 4), periosteal elevation (n = 2), or a combination of these two findings (n = 1). CONCLUSION: High-spatial-resolution US is a reliable diagnostic tool for the evaluation of occult scaphoid fractures and should be considered an adequate alternative diagnostic tool prior to computed tomography or MR imaging.     

Detection of small, functional islet cell tumors in the pancreas: selection of MR imaging sequences for optimal sensitivity

PURPOSE: To determine the sensitivity and specificity of magnetic resonance (MR) imaging for depicting pancreatic small, functional islet cell tumors and the minimum number of sequences for expedient diagnosis. MATERIALS AND METHODS: Twenty-eight patients clinically suspected to have functional islet cell tumors underwent T1- and T2-weighted spin-echo (SE) MR imaging with and without fat suppression, T2-weighted fast SE imaging, and spoiled gradient-echo (GRE) imaging before and after injection of gadopentetate dimeglumine. Sensitivity, specificity, and the best and minimum number of sequences for definitive diagnosis were determined. RESULTS: MR images depicted proved islet cell tumors in 17 of 20 patients (sensitivity, 85%). Images were true-negative in eight patients with negative follow-up examination results for more than 1 year. Specificity was 100%; positive predictive value, 100%; and negative predictive value, 73%. Among 20 patients with tumor, T1-weighted SE images with fat suppression and nonenhanced spoiled GRE images each showed lesions in 15 (75%); T2-weighted conventional SE with fat suppression, in 13 (65%); gadolinium-enhanced spoiled GRE, in 12 (60%); and T2-weighted fast SE, in seven of 10 patients (70%). CONCLUSION: MR imaging accurately depicts small islet cell tumors. T2-weighted fast SE and spoiled GRE sequences usually suffice. Gadolinium-enhanced sequences are needed only if MR imaging results are equivocal or negative.     

壶腹部肿瘤的CT诊断

目的 探讨CT在壶腹部肿瘤的诊断价值。方法 回顾分析29例经手术和病理确诊为壶腹部肿瘤的CT表现和临床资料。结果 胰头癌20例，胆管癌6例。壶腹癌3例。上述3种肿瘤具有不同的CT征象。结论 CT检查不仅能发现三种疾病的共性。还能根据各自的特征进行鉴别诊断。     

Hepatic tumors treated with percutaneous radio-frequency ablation: CT and MR imaging follow-up

PURPOSE: To describe the appearance of hepatic tumors treated with radio-frequency (RF) ablation on computed tomographic (CT) and magnetic resonance (MR) images and the pattern of residual tumor at the site of RF ablation and to assess prospectively the sensitivity, specificity, and positive and negative predictive CT and MR imaging values in the evaluation of RF treatment. MATERIALS AND METHODS: Thirty-one patients with 50 tumors (nine hepatocellular carcinomas and 41 metastases) treated with RF ablation underwent CT and MR imaging on the same day at 2, 4, and 6 months; CT was performed every 3 months thereafter. CT and MR findings were interpreted separately and prospectively by two reviewers with consensus. For both imaging techniques, appearance of the treated area, treatment efficacy, and complications were assessed at each time. Sensitivity and specificity were determined by using the McNemar test. RESULTS: After a mean follow-up of 19 months, nine tumors showed local regrowth. At 2 months, MR imaging depicted more local regrowths (eight of nine; sensitivity, 89%) than did CT (four of nine; sensitivity, 44%) but without significant differences (P =.12). In two cases, only T2-weighted imaging depicted local regrowth. All nine lesions became conspicuous at 4-month follow-up with both techniques. At 2 months, thin peripheral rim enhancement and arterioportal shunting were found in 24% and 12%, respectively, of the treated tumors. These findings disappeared thereafter and are not linked to tumor regrowth. CONCLUSION: Despite the small number of patients, CT and MR imaging may depicted all local regrowth at 4 months or sooner. MR imaging may have an edge over CT in the early detection of local regrowth.     

Preoperative MR imaging of anal fistulas: Does it really help the surgeon?

PURPOSE: To evaluate the accuracy of magnetic resonance (MR) imaging with a quadrature phased-array coil for the detection of anal fistulas and to evaluate the additional clinical value of preoperative MR imaging, as compared with surgery alone. MATERIALS AND METHODS: Fifty-six patients with anal fistulas underwent high-spatial-resolution MR imaging. Twenty-four had a primary fistula; 17, a recurrent fistula; and 15, a fistula associated with Crohn disease. MR imaging findings were withheld from the surgeon until surgery ended and verified, and surgery continued when required. RESULTS: MR imaging provided important additional information in 12 (21%) of 56 patients. In patients with Crohn disease, the benefit was 40% (six of 15); in patients with recurrent fistulas, 24% (four of 17); and in patients with primary fistulas, 8% (two of 24). The difference between patients with or without Crohn disease and between patients with a simple fistula versus the rest was significant (P <.05). The sensitivity and specificity for detecting fistula tracks were 100% and 86%, respectively; abscesses, 96% and 97%, respectively; horseshoe fistulas, 100% and 100%, respectively; and internal openings, 96% and 90%, respectively. CONCLUSION: High-spatial-resolution MR imaging is accurate for detecting anal fistulas. It provides important additional information in patients with Crohn disease-related and recurrent anal fistulas and is recommended in their preoperative work-up.     

Diffusion-weighted MR imaging of cholesteatoma in pediatric and adult patients who have undergone middle ear surgery

OBJECTIVE: The aim of this prospective study was to determine the role of diffusion-weighted MR imaging combined with conventional MR imaging for the detection of residual or recurrent cholesteatoma in patients who have undergone middle ear surgery. SUBJECTS AND METHODS: Twenty-two patients who had undergone resection of cholesteatoma were referred for MR imaging. MR imaging (1.5 T) was performed using a diffusion-weighted single-shot spin-echo echoplanar sequence, a proton density and T2-weighted double-echo turbo spin-echo sequence, and T1-weighted spin-echo sequences before and after IV injection of gadopentetate dimeglumine (0.1 mmol/kg of body weight). An experienced reviewer evaluated the diffusion-weighted MR images for the presence of a high-signal-intensity cholesteatoma. Imaging findings were correlated with findings from surgery in 17 patients and with findings from clinical follow-up examination in five patients. RESULTS: Diffusion-weighted MR imaging combined with conventional MR imaging depicted 10 of 13 cholesteatomas (sensitivity, 77%). The three lesions that were missed were smaller than 5 mm. All the MR images of patients without cholesteatoma were correctly interpreted as showing negative findings for cholesteatoma (specificity, 100%). The positive predictive value and negative predictive value were 100% and 75%, respectively. CONCLUSION: Diffusion-weighted MR imaging combined with conventional MR imaging can confirm residual or recurrent cholesteatoma in patients who have undergone middle ear surgery by showing a high-signal-intensity lesion. Because tumors smaller than 5 mm may be missed, a diffusion-weighted MR imaging study with negative findings does not exclude small residual or recurrent cholesteatoma.     

Treated ovarian cancer: MR imaging, laparotomy reassessment, and serum CA-125 values compared with clinical outcome at 1 year

PURPOSE: To compare retrospectively the use of magnetic resonance (MR) imaging, laparotomy reassessment, and serum CA-125 values in predicting the presence of residual tumor in women who have been treated for ovarian cancer. MATERIALS AND METHODS: This study was approved by the institutional review board, and informed consent was waived. The study was compliant with the Health Insurance Portability and Accountability Act. Seventy-six women (mean age, 59 years) with treated ovarian cancer underwent preoperative MR imaging of the abdomen and pelvis with intravenous gadolinium-based and intraluminal barium contrast material. MR findings were compared with surgical and histopathologic findings, serial and static serum CA-125 values, and clinical follow-up results. Tumor absence was proved with normal surgical results and by following up patients for at least 1 year, with no evidence of residual tumor at serial CA-125 analysis or subsequent laparotomy. McNemar test for correlated proportions was used for statistical analysis. RESULTS: Sixty-eight women had residual tumor proved at laparotomy and biopsy or at clinical follow-up. Eight patients had no evidence of residual tumor. Gadolinium-enhanced MR imaging depicted residual tumor in 61 patients (sensitivity, 90%; specificity, 88%; accuracy, 89%) compared with laparotomy, which demonstrated residual tumor in 60 patients (sensitivity, 88%; specificity, 100%; accuracy, 89%) and CA-125 values, which demonstrated residual tumor in 44 patients (sensitivity, 65%; specificity, 88%; accuracy, 67%) (P < .01). The positive predictive values for MR imaging, laparotomy, and serum CA-125 values were 98%, 100%, and 98%, respectively, whereas the corresponding negative predictive values were 50%, 50%, and 23%, respectively. In 14 patients, there was a discrepancy between the results of MR imaging and those of laparotomy. In seven patients, MR imaging depicted residual tumor that was not found at laparotomy but was proved at subsequent biopsy or clinical and imaging follow-up, with an increasing serum CA-125 level. In six patients, MR findings were normal, and subsequent laparotomy revealed small-volume residual tumor. Residual tumor was incorrectly predicted with MR imaging in one patient who had no surgical or clinical evidence of residual tumor for 1 year. CONCLUSION: Gadolinium-enhanced spoiled gradient-echo MR imaging depicts residual tumor in women with treated ovarian cancer, with an accuracy, positive predictive value, and negative predictive value that are comparable to those of laparotomy and superior to those of serum CA-125 values alone.     

Apparent diffusion coefficient mapping of salivary gland tumors: prediction of the benignancy and malignancy

BACKGROUND AND PURPOSE: Preoperative prediction of tumor malignancy is clinically very important, because this information strongly influences the surgical plan. We evaluate the preoperative apparent diffusion coefficient (ADC) maps of benign and malignant salivary gland tumors. MATERIALS AND METHODS: High-resolution MR imaging was performed on 31 patients with benign or malignant salivary gland tumors; ADC maps of the tumors were also obtained. Surface coils of 47 or 110 mm diameter were used to improve the image resolution. The ADCs were compared with histologic features of the excised tumors. RESULTS: The ADC maps effectively depicted the histologic features of the salivary gland tumors, such as presence of cancer cells, myxomatous tissues, fibrosis, necrosis, cyst formation, and lymphoid tissues. The ADC maps showed that more frequent areas with high ADCs (> or = 1.8 x 10(-3) mm(2)/s) were significantly greater in benign tumors than in malignant tumors. The sensitivity and specificity for high ADC occupying fewer than 5% of the area of a tumor was 89% and 100%, respectively, resulting in 97% accuracy, 100% positive predictive value, and 96% negative predictive value. CONCLUSION: The ADC may provide preoperative tissue characterization of the salivary gland tumors.     

High-spatial-resolution 3D balanced turbo field-echo technique for MR angiography of the renal arteries: initial experience

PURPOSE: To compare a multislab balanced turbo field-echo magnetic resonance (MR) angiographic technique, without the use of a contrast agent, with digital subtraction angiography (DSA) for imaging of the renal arteries. MATERIALS AND METHODS: Twenty-five randomly selected patients (eight women and 17 men; age range, 27-88 years; mean age, 72 years) suspected of having renal artery stenosis underwent both DSA and balanced turbo field-echo MR angiography. A consensus result was obtained among three radiologists in evaluation of main renal arteries on balanced turbo field-echo images and DSA images. Sensitivity, specificity, and negative and positive predictive values of the balanced turbo field-echo technique were calculated, and receiver operating characteristic analysis was performed for depiction of hemodynamically significant stenosis. Cohen kappa analysis was used to assess agreement between the two imaging methods in grading of stenoses and depiction of significant stenosis. Accessory renal arteries also were evaluated. RESULTS: Fifty main renal arteries and 11 accessory arteries were fully depicted with DSA. DSA depicted 11 stenotic lesions in the main renal arteries. In comparison, balanced turbo field-echo MR angiography enabled visualization of 46 of 50 main renal arteries to their first branching points and depicted 10 of 11 accessory arteries. Sensitivity, specificity, negative predictive value, and positive predictive value of this technique for depiction of significant stenosis were 100% (four of four), 98% (41 of 42), 100% (41 of 41), and 80% (four of five), respectively. The area under the receiver operating characteristic curve was 0.988. kappa was 0.782 for grading of stenoses and 0.877 for depiction of significant stenosis. CONCLUSION: Multislab balanced turbo field-echo imaging has potential as an MR angiography technique for depiction of normal and diseased renal arteries.     

Hemorrhagic shearing lesions in children and adolescents with posttraumatic diffuse axonal injury: improved detection and initial results

PURPOSE: To compare the effectiveness of a high-spatial-resolution susceptibility-weighted (SW) magnetic resonance (MR) imaging technique with that of a conventional gradient-recalled-echo (GRE) MR imaging technique for detection of hemorrhage in children and adolescents with diffuse axonal injury (DAI). MATERIALS AND METHODS: Seven young patients with a mean Glasgow Coma Scale score of 7 +/- 4 (SD) at admission were imaged a mean of 5 days +/- 3 after injury. High-spatial-resolution three-dimensional GRE imaging performed with postprocessing by using a normalized phase mask was compared with conventional GRE MR imaging. The total and mean values of lesion number and apparent hemorrhage volume load determined with both examinations were compared. Mean values were compared by using paired t test analysis. Differences were considered to be significant at P < or =.05. RESULTS: Hemorrhagic lesions were much more visible on SW MR images than on conventional GRE MR images. SW MR imaging depicted 1,038 hemorrhagic DAI lesions with an apparent total hemorrhage volume of 57,946 mm3. GRE MR imaging depicted 162 lesions with an apparent total hemorrhage volume of 28,893 mm3. SW MR imaging depicted a significantly higher mean number of lesions in all patients than did GRE MR imaging, according to results of visual (P =.004) and computer (P =.004) counting analyses. The mean hemorrhage volume load for all patients also was significantly greater (P =.014) by using SW MR imaging according to computer analysis. SW MR imaging appeared to depict much smaller hemorrhagic lesions than GRE MR imaging. The majority (59%) of individual hemorrhagic DAI lesions seen on SW MR images were small in area (<10 mm(2)), whereas the majority (43%) of lesions seen on GRE images were larger in area (10-20 mm(2)). CONCLUSION: SW MR imaging depicts significantly more small hemorrhagic lesions than does conventional GRE MR imaging and therefore has the potential to improve diagnosis of DAI.     

Atherosclerotic plaques: classification and characterization with T2-weighted high-spatial-resolution MR imaging-- an in vitro study

PURPOSE: To evaluate if T2-weighted high-spatial-resolution magnetic resonance (MR) imaging (117 microm per pixel) can help accurate classification of atherosclerotic plaques. MATERIALS AND METHODS: Thirty human arteries and 11 carotid endarterectomy specimens from 31 patients underwent T2-weighted MR imaging (2-T magnet; repetition time, 2,000 msec; echo time, 50 msec) at room temperature. After imaging, Bouin fixative was used to fix 26 arteries, and the other 15 arteries were fixed by means of freezing. Specimens were stained with hematoxylin-eosin and safranin or Sudan lipid stain. MR images and histologic slices were classified independently by two radiologists and a pathologist, respectively, on the basis of the American Heart Association classification. RESULTS: Results with MR imaging were the following: type I-II plaques, sensitivity of 67% and specificity of 100%; type IV-Va plaques, sensitivity of 74% and specificity of 85%; type Vb plaques, sensitivity of 90% and specificity of 100%; type Vc plaques, sensitivity of 80% and specificity of 90%. No type III plaque was diagnosed in the study. The overall kappa value was 0.68. CONCLUSION: High-spatial-resolution MR imaging with T2 weighting alone can help accurate classification of fibrocalcic plaques (type Vb), but it is subject to limitations for the classification and analysis of other types of atherosclerotic plaques.     

MR imaging of ampullary carcinomas

OBJECTIVE: The purpose of this study was to demonstrate the appearance of ampullary carcinomas on MR images. METHODS: Sixteen patients with ampullary carcinomas underwent MR imaging. Tumor detectability, signal intensity of the tumor, and enhancement pattern on dynamic study were analyzed. MR cholangiopancreatography (MRCP) findings were assessed and were compared with the endoscopic retrograde cholangiopancreatography (ERCP) findings. RESULTS: Signal intensities of the tumor on each image were various. Dynamic study detected all tumors except one, and all detected tumors showed delayed enhancement. MRCP delineated more than half of the tumors as a filling defect within the duodenal fluid and clearly demonstrated pancreaticobiliary ductal. CONCLUSIONS: Dynamic study is mandatory in diagnosing ampullary carcinoma, because it can depict most of the tumors, and delayed enhancement of such tumors is characteristic in case of ampullary carcinoma. MRCP can provide reliable information about pancreaticobiliary duct and it can replace diagnostic ERCP.     

Detection of pulmonary vein and left atrial scar after catheter ablation with three-dimensional navigator-gated delayed enhancement MR imaging: initial experience

PURPOSE: To prospectively evaluate whether scar caused by radiofrequency (RF) ablation of the left atrium (LA) in patients with atrial fibrillation can be depicted with high-spatial-resolution delayed enhancement magnetic resonance (MR) imaging. MATERIALS AND METHODS: All 23 subjects (16 men, seven women; mean age, 54 years +/- 13 [standard deviation]) provided written informed consent; the study was approved by the local institutional review board and was HIPAA compliant. A high-spatial-resolution free-breathing delayed enhancement MR imaging method was developed to detect scar (ie, ablated tissue) in the LA and pulmonary veins (PVs). The LA in 15 patients before ablation and in 18 patients at least 30 days after ablation was examined. A reader with 4 years of experience assessed presence of delayed enhancement on images and circumferential completeness. Signal-to-noise and contrast-to-noise ratios were measured and compared with an unpaired t test. The relationship between measurements of enhancement thickness at the interatrial septum and the number of days after ablation was investigated. RESULTS: No subject demonstrated preablation delayed enhancement of the atrial or PV wall, whereas postablation delayed enhancement was identified in all (100%). In patients after ablation, a partial to completely circumferential delayed enhancement pattern could be identified for the left inferior PV that encompassed 88% +/- 11 of the circumference, but only 62% of patients demonstrated more than 90% circumferential delayed enhancement. The signal-to-noise ratio of blood was 12, and the signal-to-noise ratios of the pre- and postablation left atrial wall were 15 and 22, respectively (P<.05). A relationship between delayed enhancement wall thickness and the inverse of the time interval from ablation was identified (P<.05). CONCLUSION: High-spatial-resolution delayed enhancement MR imaging allows noninvasive identification of scar induced by RF ablation following isolation therapy of the PV.     

Diagnosis and staging of pancreatic cancer: comparison of mangafodipir trisodium-enhanced MR imaging and contrast-enhanced helical hydro-CT

OBJECTIVE: The purpose of this study was to compare mangafodipir trisodium-enhanced MR imaging performed with a phased array coil and contrast-enhanced single-detector helical CT for accuracy in the detection and local staging of pancreatic adenocarcinoma and in the differentiation between cancer and focal pancreatitis. SUBJECTS AND METHODS: Forty-two patients with suspected pancreatic masses underwent contrast-enhanced helical CT and mangafodipir trisodium-enhanced MR imaging at 1.5 T. The images were assessed for the presence or absence of tumors; characterization of masses; and presence of vascular invasion, lymph node metastases, or liver metastases. Imaging findings were correlated with findings at laparotomy, laparoscopy, biopsy, or follow-up. RESULTS: Focal masses were present in 36 patients (cancer, n = 26; focal pancreatitis, n = 7; other, n = 3). The sensitivity for lesion detection of MR imaging was 100% and of CT, 94%. Two small malignant lesions were missed on CT. For the diagnosis of tumor nonresectability, the sensitivity of MR imaging and CT was 90% and 80%, respectively. Liver metastases were missed on MR imaging in one of the eight patients and on CT in four. For differentiation between adenocarcinoma and nonadenocarcinoma, the sensitivity of MR imaging was 100% (positive predictive value, 90%; negative predictive value, 100%), and the sensitivity of CT was 92% (positive predictive value, 80%; negative predictive value, 67%). Receiver operating characteristic analysis revealed that the mean area under the curve for MR imaging was 0.920 and for CT, 0.832 (not significant). CONCLUSION: Mangafodipir trisodium-enhanced MR imaging is as accurate as contrast-enhanced helical CT for the detection and staging of pancreatic cancer but offers improved detection of small pancreatic metastases and of liver metastases compared with CT.     

多层螺旋CT判断壶腹周围癌的可切除性

目的:探讨多层螺旋CT(MSCT)判断壶腹周围癌可切除性的价值。材料和方法:回顾性分析经病理证实的35例壶腹周围癌患者的CT表现,并与手术或十二指肠胰胆管造影(ERCP)所见对照。结果:经MSCT检查35例均发现肿瘤,增强扫描肿瘤本身可见不同程度增强,其中16例经图像后处理,35例均清晰显示肿瘤及肿瘤与周围组织、血管的关系。根据MSCT表现判断26例肿瘤可手术切除,19例接受了肿瘤切除术,9例有转移或血管受累征象手术不能切除。结论:MSCT动态增强扫描与三维重建技术相结合能清晰地显示壶腹部肿瘤及其与周围结构的关系,对于壶腹周围癌可切除性的判断及预后有重要的指导作用。     

Pancreatic carcinoma: MR, MR angiography and dynamic helical CT in the evaluation of vascular invasion

OBJECTIVE: To assess the value of MR angiography in combination with contrast-enhanced MR imaging, and to compare MR imaging including MR angiography with dynamic contrast-enhanced dual phase helical CT in the preoperative assessment of vascular invasion in patients with suspected pancreatic carcinoma. METHODS AND MATERIAL: MR imaging only, MR imaging including MR angiography and dynamic contrast-enhanced dual phase helical CT images of 48 patients who were operated due to suspicion of pancreas cancer were correlated with the surgery results in terms of vascular invasion. Pathologic diagnosis were pancreatic adenocarcinoma in 31 patients of which nine had surgically confirmed vascular invasion. Sensitivity, specificity, predictive values (including 95% confidence intervals) and accuracy of MR imaging only, MR imaging including MR angiography and helical CT were calculated. RESULTS: Sensitivity, specificity, positive and negative predictive values and accuracy were 56, 100, 100, 85, 87%; 67, 100, 100, 88, 90% and 67, 100, 100, 88, 90%, respectively, for MR imaging only, MR imaging including MR angiography and helical CT in the adenocarcinoma group. The corresponding figures in the overall study group were 56, 97, 83, 90, 90%; 67, 97, 86, 93, 92% and 67, 97, 86, 93, 92%. Confidence intervals (95%) showed that the differences in the diagnostic efficacy of the techniques were not statistically significant in the overall study group, but the confidence intervals were undefined in the adenocarcinoma group due to the small sample size. CONCLUSION: Diagnostic efficacy of MR imaging when combined with MR angiography is equal to that of dynamic contrast-enhanced dual phase helical CT in the assessment of vascular invasion of pancreatic tumors.     

Prospective evaluation of pancreatic tumors: accuracy of MR imaging with MR cholangiopancreatography and MR angiography

PURPOSE: To prospectively assess accuracy of magnetic resonance (MR) imaging, MR cholangiopancreatography (MRCP), and MR angiography in patients suspected of having pancreatic tumors. MATERIALS AND METHODS: Sixty-six patients suspected of having pancreatic tumors underwent MR imaging (unenhanced and contrast material-enhanced MR, MRCP, and contrast-enhanced MR angiography). Two blinded readers prospectively analyzed the images by consensus, and results were correlated with surgery, biopsy, or follow-up findings. Results were tabulated in two-by-two tables. RESULTS: MR assessment of pancreatic lesion status (differentiation of benign vs malignant) resulted in 60 correct diagnoses (accuracy, 91%), and six (10%) false diagnoses. Among histologically proved malignant tumors, MR imaging yielded correct diagnoses in 42 of 44 patients (sensitivity, 95%; 95% CI: 85%, 99%), whereas 18 of 22 patients with benign findings were classified correctly. At MR imaging, findings in four patients with chronic pancreatitis were wrongly categorized as malignant tumors (specificity, 82%; 95% CI: 60%, 95%), and in one patient, a distal common bile duct carcinoma was not detected. In no patient with pancreatic adenocarcinoma was this tumor misdiagnosed as benign. In patients with malignant tumors who underwent resection, local-regional tumor growth and vascular infiltration were accurately classified in 89% and 94%, respectively. MR imaging depicted histologically proved synchronous hepatic metastases in 82%. The positive and negative predictive values for cancer nonresectability were 90% and 83%, respectively, and the accuracy, sensitivity, and specificity were 85%, 69%, and 95%, respectively. CONCLUSION: Unenhanced and contrast-enhanced MR imaging with MRCP and MR angiography offers potential as a noninvasive tool for assessment of patients suspected of having pancreatic tumors.     

MRI combined with MR cholangiopancreatography versus helical CT in the evaluation of patients with suspected periampullary tumors: a prospective comparative study

PURPOSE: To establish the diagnostic accuracy of MRI including MR cholangiopancreatography (MRCP) compared with helical CT in the differentiation of malignant and benign lesions in the periampullary region. MATERIAL AND METHODS: Fifty-one patients (27 M, 24 F, mean age 66 years, range 39-86 years) with obstructive jaundice and sonographic evidence of intra- and extrahepatic bile duct dilatation (n=31) or suspicion of periampullary tumor, based on previously performed ultrasound and/or CT examination (n=20), were studied. MRI with MRCP and helical CT were reviewed blindly under standardized conditions. Lesion status (differentiation of malignant versus benign) was rated on a 5-point diagnostic confidence scale. Reference standards for comparison were findings at surgery or laparoscopy and/ or the clinical outcome. The predictive value of imaging findings was determined with multivariate logistic regression analysis. RESULTS: The areas under the receiver operating characteristic curve were 0.96 for MRI with MRCP and 0.81 for CT (P <0.05). Multivariate analysis of eight imaging variables at MRI indicated that a stricture with malignant characteristics at MRCP was the best predictor of malignancy. CONCLUSION: MRI with MRCP was significantly more accurate than CT in differentiating between malignant and benign lesions in patients with suspected periampullary tumors, mainly due to the information obtained on the MRCP images of the biliary and pancreatic duct anatomy.