氟化胶囊用以提高细胞疗法的功能,增加免疫保护以及MR、CT和US影像上的可视性

目的研发新的可能增加细胞功能,为异种移植细胞提供免疫保护,同时可在多种影像方法中成像,含有过氟化碳(PFC)免疫防护海藻酸钠微胶囊的构成。材料与方法 所     

Fat replacement with absence of acinar and ductal structure in the pancreatic body and tail

We report an unusual case of fat replacement of the pancreatic body and tail. Findings on contrast-enhanced computed tomography and ERCP could be confused with dorsal pancreas agenesis. Histopathologic examination of the resected specimen revealed massive fat replacement with complete absence of the acinar and ductal tissue and scattered islets of Langerhans.     

Ultrasonography of the pancreatic tail through spleen and through fluid-filled stomach

In the present study ultrasonography observed the tail of the pancreas more frequently through the spleen than by any other approach. If the splenic approach fails, examination through the fluid-filled stomach may be tried.     

Air in the main pancreatic duct: demonstration with US

Air in the pancreas--nearly always related to an abscess or a pancreatic fistula--is rarely demonstrated. Over a 3-year period, the authors detected air in the main pancreatic duct with ultrasonography (US) in 11 patients. The ductal caliber was normal in five patients and dilated in six. At US, air in the main pancreatic duct is characterized by strongly echogenic foci or echogenic lines in the duct, casting acoustic shadows or producing reverberation artifacts. It is likely that in patients who have biliary-enteric anastomoses or have undergone sphincterotomy, air in the duct of Wirsung is the result of biliary-pancreatic reflux. In patients who have not undergone such operations, the likely cause of pancreatic gas is duodenal-pancreatic duct reflux. Pancreatic gas may be related to causes other than a pancreatic abscess or fistula; it is therefore important for clinicians to realize that pancreatic ductal gas seen on US images may be secondary to prior surgery or due to sphincter of Oddi dysfunction.     

Improved visualization of posterior fossa with clivoaxial CT scanning plane

Eighteen patients clinically suspected of having acoustic neurinoma were studied in both orbitomeatal and clivoaxial (CA) (the plane perpendicular to clivus) CT scanning planes during the same sessions. On the CA cuts there were highly significantly less (p less than 0.001) artifacts. Also, the tentorium was highly significantly (p less than 0.001) better visualized on the CA cuts. CA cuts could be recommended in cases when artifacts disturb the diagnostics of posterior fossa pathology or when detailed topographic information about pathologic anatomy round the tentorium is needed.     

Improved visualization of breast lesions with gadolinium-enhanced magnetization transfer MR imaging

A pulse sequence with magnetization transfer as the main contrast mechanism (MT-FLASH) was developed for improved imaging of breast lesions that requires neither fat suppression nor postprocessing. After optimization of the sequence in phantom and volunteer studies, a clinical pilot study with 14 patients was performed. In carcinomas the relative signal increase after Gd-DTPA administration was on average 34% in MT-FLASH images compared with 169% in conventional T₁ weighted (T1W) three-dimensional FLASH images. In MT-FLASH images, all lesions demonstrated a signal intensity higher than that of fat; in T1W images, all lesions have a lower signal intensity. The average postcontrast carcinoma-to-fat contrast-to-noise ratios were +11.6 and ?14.2, respectively. The conspicutty of 12 of 13 carcinomas was improved in postcontrast MT-FLASH images compared with postcontrast T1w images. Thus, MT-FLASH imaging enables excellent visualization of Gd-DTPA-enhancing breast lesions.     

Crohn disease of the ileocecal region: US visualization of the appendix

In three of 52 consecutive patients with a painful mass in the right lower quadrant, ultrasound (US) disclosed severe mural thickening of the terminal ileum and cecum and moderate mural thickening of the appendix. In all three, the tentative diagnosis of Crohn disease was subsequently confirmed. If these US features are found in a patient with a suspected appendiceal mass, the diagnosis of Crohn disease must be seriously considered, and further evaluation is imperative.     

Improved visualization of the radial insertion of the biceps tendon at ultrasound with a lateral approach

We report a new lateral approach for ultrasound visualization of the distal biceps tendon. A cadaver specimen was dissected to study distal biceps anatomy relevant to this approach. Sonograms obtained in volunteers and patients are provided to illustrate this alternative method.     

Blunt abdominal injury in the pregnant patient: detection with US

PURPOSE: To determine the accuracy of ultrasonography (US) for the detection of blunt intraabdominal injury in pregnant patients and to compare differences between pregnant and nonpregnant patients of childbearing age. MATERIALS AND METHODS: A retrospective review of results of all consecutive emergency blunt trauma US examinations performed at a level I trauma center from January 1995 to June 2002 was conducted. Data on demographics, free fluid location, and patient outcome were collected. Injuries were determined on the basis of results of computed tomography and/or laparotomy. The Student t test was used to detect differences between continuous variables, and chi(2) analysis was used to evaluate differences between proportions. RESULTS: A total of 2319 US examinations for blunt trauma were performed in girls and women between the ages of 10 and 50 years. There were 328 pregnant patients, 23 of whom had intraabdominal injury. The mean age of the pregnant patients was 24.7 years +/- 6.1 (standard deviation) (age range, 14-42 years). In pregnant patients, the sensitivity of US was 61% (14 of 23 patients), the specificity was 94.4% (288 of 305 patients), and the accuracy was 92.1% (302 of 328 patients). Pregnant patients were significantly more likely to have sustained injuries from assault (odds ratio: 2.6, P < .001). The most common pattern of free fluid accumulation detected at US in pregnant patients was that of fluid in the left and right upper quadrants and pelvis (n = 4, 29%); the second most common pattern was one of isolated pelvic fluid (n = 3, 21%). CONCLUSION: For detection of intraabdominal injury, US was less sensitive in pregnant patients than in nonpregnant patients but was highly specific in both subgroups. The sensitivity of US was highest in pregnant patients during the first trimester.     

应用空间选择性反转恢复脉冲的MRCP观察主胰管内胰液的分泌和流动

目的探讨应用空间选择性反转恢复脉冲的MRCP无创地观察健康志愿者和胰腺疾病病人胰液生理性流动的可行性。材料与方法此研究获机构审查委员会批准,并取得病人的知情同意书。共包含12名健康志愿者和3例急性胰     

Transperineal US: alternative technique to improve visualization of the presenting fetal part

Transperineal ultrasound (TPU) was used as an alternative imaging technique to evaluate the anatomy of the presenting part in 27 second- and third-trimester fetuses when transabdominal ultrasound (US) images were suboptimal. Use of TPU improved visualization of the distal fetal spine in 20 of 21 breech cases, providing sufficient information regarding bone anatomy to rule out splaying of the posterior elements. In addition, the intact skin surface overlying the distal spine, not seen at transabdominal US, was well demonstrated at TPU in 18 of these fetuses. TPU was used to improve assessment of intracranial anatomy in six cases with a cephalic presentation in which the fetal head was located low in the maternal pelvis and could not be adequately visualized with the transabdominal technique. In one of these cases, TPU offered improved visualization of anencephaly. Use of TPU should be considered to optimize visualization of the presenting fetal part when results at transabdominal US are suboptimal and the poorly seen part overlies the maternal cervix.     

Localization of pancreatic insulinoma: comparison of pre- and intraoperative US with CT and angiography

Methods of preoperative radiologic localization of insulinoma were compared in 52 patients, 44 of whom had solitary tumors. Examinations performed in these 44 patients were preoperative ultrasonography (US) in 28, angiography in 26, and computed tomography in 23. Prospective sensitivities were 61%, 54%, and 30%, respectively. Imaging sensitivities were lower for the eight patients with multiple insulinomas. In 28 of the 44 patients, intraoperative US was performed without the examiner being aware of the surgical findings. The sensitivity was 84%. Four insulinomas were not palpable but were visualized sonographically. The combined sensitivity of intraoperative US and surgical palpation for detecting solitary insulinomas was 100%. High-frequency intraoperative US is valuable for detecting occult solitary insulinomas and considerably useful for determining the proximity of insulinomas to the pancreatic and bile ducts.     

Computed diffusion-weighted MR imaging for visualization of pancreatic adenocarcinoma: Comparison with acquired diffusion-weighted imaging

ObjectiveTo assess the feasibility of computed diffusion-weighted imaging (cDWI) in comparison with directly acquired DWI for visualizing pancreatic adenocarcinomas.Materials and methodsPatients with pancreatic adenocarcinoma underwent DWI at b-values of 0, 1000 (DWI₁₀₀₀), 1500 (DWI₁₅₀₀) and 2000 (DWI₂₀₀₀) s/mm². From DWIs at b-values of 0 and 1000 s/mm², we generated cDWIs at b-values of 1500 (cDWI₁₅₀₀) and 2000 (cDWI₂₀₀₀) s/mm². DWI findings of pancreatic adenocarcinomas (clear hyperintensity; hyperintensity with an unclear distal border; and isointensity), the image quality and the tumor to pancreas contrast ratio (CR) were compared between directly acquired DWI and cDWI.ResultsAmong the 63 included patients, clear hyperintense tumors were seen in 35 on DWI₁₀₀₀, 50 on DWI₁₅₀₀, 50 on cDWI₁₅₀₀, 53 on DWI₂₀₀₀ and 44 on cDWI₂₀₀₀. Incidence of clear hyperintense tumors was significantly higher on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P = 0.013). There was no significant difference in the incidence of clear hyperintense tumors between DWI₁₅₀₀ and cDWI₁₅₀₀ (P > 0.999), but a lower incidence was seen on cDWI₂₀₀₀ than on DWI₂₀₀₀ (P = 0.028). Image quality was lower on cDWI than on DWI at b-values of 1500 (P = 0.002) and 2000 s/mm² (P < 0.001). The tumor to distal pancreas CR was significantly higher on cDWI₂₀₀₀ than on cDWI₁₅₀₀ (P < 0.001), and on cDWI₁₅₀₀ than on DWI₁₀₀₀ (P < 0.001). The cDWI showed a significantly higher tumor to distal pancreas CR than DWI at b-values of 1500 (P = 0.004) and 2000 s/mm² (P < 0.001).ConclusionscDWI₁₅₀₀ generated from b-values of 0 and 1000 s/mm² should be considered more effective than DWI₁₀₀₀ and at least as effective as DWI₁₅₀₀.     

Diffusion-weighted MR imaging of the pancreas: optimizing b-value for visualization of pancreatic adenocarcinoma

Objectives

To determine the optimal b-value of 3.0-T diffusion-weighted imaging (DWI) for visualizing pancreatic adenocarcinomas

Methods

Fifty-five patients with histologically confirmed pancreatic adenocarcinoma underwent DWI with different b-values (b?=?500, 1000, 1500, and 2000 s/mm²) at 3.0 T. For each b-value, we retrospectively evaluated DWI findings of pancreatic adenocarcinomas (clear hyperintensity relative to the surrounding pancreas, hyperintensity with an unclear distal border, and isointensity) and image quality, and measured tumour-to-pancreas signal intensity (SI) ratios. DWI findings, image quality, and tumour-to-pancreas SI ratios were compared between the four b-values.

Results

There was a significantly higher incidence of tumours showing clear hyperintensity on DWI with b-value of 1500 s/mm² than on that with b-value of 1000 s/mm² (P?<?0.001), and on DWI with b-value of 1000 s/mm² than on that with b-value of 500 s/mm² (P?<?0.001). The tumour-to-distal pancreas SI ratio was higher with b-value of 1500 s/mm² than with b-value of 1000 s/mm² (P?<?0.001), and with b-value of 1000 s/mm² than with b-value of 500 s/mm² (P?<?0.001). A lower image quality was obtained at increasing b-values (P?<?0.001); the lowest scores were observed with b-value of 2000 s/mm².

Conclusions

The use of b?=?1500 s/mm² for 3.0-T DWI can improve the delineation of pancreatic adenocarcinomas.

Key Points

? Diffusion-weighted imaging (DWI) has been used for diagnosing pancreatic adenocarcinoma ? The techniques for DWI, including the choice of b-values, vary considerably ? DWI often fails to delineate pancreatic adenocarcinomas because of hyperintense pancreas ? DWI with a higher b-value can improve the tumour delineation ? The lowest image quality was obtained on DWI with b-value?=?2000 s/mm ²