螺旋CT双期扫描诊断伴肝硬化的小肝癌的探讨

目的 探讨螺旋 CT双期增强扫描诊断伴肝硬化的小肝癌的价值。方法 1 4例伴肝硬化的小肝癌患者手术及病理发现小肝癌病灶 2 1个 (直径≤ 3cm) ,回顾性分析螺旋 CT双期增强扫描的结果 ,比较小肝癌在动脉期和门脉期内强化类型、检出率及诊断正确率。结果 动脉期检出率为 85.7% ( 1 8/2 1 ) ,门脉期有 71 .4% ( 1 5/2 1 )。 6 6 .7%小肝癌动脉期为均一高密度。门脉期定性正确率为 52 .4%。联合动脉期和静脉期后 ,其检出率和定性正确率分别增加至 90 .5%和 80 .9%。结论 动脉期扫描明显增加小肝癌的检出 ,两期结合能提高检出率及定性正确率。

隐源性脑脓肿的影像学误诊问题

目的 探讨如何提高隐源性脑脓肿的诊断水平 ,降低误诊率。方法 回顾分析 2 6例经头颅 CT或 MRI或临床确诊的隐源性脑脓肿。结果 本组 2 6例首次行头颅 CT或 MRI描扫时误诊 10例 ,总误诊率为 38.46 % ,其中 4例误诊为脑囊虫病 ,5例误诊为脑转移瘤 ,1例误诊为脑胶质瘤。结论 CT、MRI是隐源性脑脓肿必不可少的检查手段 ,可以明显提高确诊率。但要注意与脑转移瘤、脑囊虫病、脑胶质瘤及结核瘤等进行鉴别 。

Radiological diagnosis of inflammatory ulcerative diseases of small bowel

AIMS To analyze the radiological features of the ul- cerative diseases of the small bowel. METHODS Thirty-five patients (20 men,15 women) with inflammatory ulcerative bowel diseases were stud- ied radiographically (barium meal and/or double con- trast study),including:11 cases of tuberculosis,13 Crohn disease,7 bowel Behcet disease,2 simple ulcer and 2 ischemic bowel disease. Diagnosis was estab- lished pathologically in 33 cases and by clinical obser- vation after therapy in 2 cases. RESULTS The lesions were located in ileum,in 9 of 11 cases of TB;in 10 of 13 cases of Crohn disease;in 5 of 7 cases of bowel Behcet disease;in 1 of 2 cases of simple ulcer and in 2 cases of ischemic bowel disease. Ulceration was always present with variable appearances. Longitudinal ulcers,and fissures were noted in Crohn disease only. There were 5 cases of large and deep ulcer and 3 occurred in bowel Behcet disease,10 of 13 cases of superficial and irregular ul- cers were tuberculous,2 cases of transverse ulcer were also tuberculous. CONCLUSIONS The morphologic appearances of the ulcer,surrounding mucosal alterations and bowel deformation were the basis for the radiologic diagnosis. Correct diagnosis was dependent on optimal X-ray ex- amination technique and proper interpretation of the morphologic changes.

侧脑室内肿瘤的CT和MRI诊断与鉴别

目的 探讨侧脑室内肿瘤的 CT和 MRI诊断价值 .方法 本组收集经手术病理证实的侧脑室内肿瘤 38例 ,年龄 6～ 72岁。CT检查 2 5例 ,其中 1 5例同时作增强扫描。MRI检查 30例 ,1 9例作增强扫描。结果 部分侧脑室肿瘤具有 CT和 MRI表现的特征性 ,部分肿瘤具有好发部位 ,部分肿瘤具有年龄学特征。CT显示肿瘤钙化较佳 ,对肿瘤的鉴别帮助很大。而 MRI的优势在于能三维成像 ,可准确显示肿瘤的位置及邻近情况。结论 侧脑室内肿瘤临床表现不典型 ,所以肿瘤的诊断主要依据其 CT和 MRI表现 ,结合发生部位和年龄特征 ,可进一步提高诊断正确率。

Volumetric fraction measurement in oil-water-gas multiphase flow with dual energy gamma-ray system

Volumetric fraction distribution measurement is a constituent part of process tomography system in oil-water-gas multiphase flow. With the technological development of nuclear radial inspection, dual-energy γ-ray techniques make it possible to investigate the concentration of the different components on the cross-section of oil-water-gas multiphase pipe-flow. The dual-energy gamma-ray technique is based on materials attenuation coefficients measurement comprised of two radioactive isotopes of 241Am and 241Cs which have emission energies at 59.5 keV and 662 keV in this project. Nuclear instruments and data acquisition system were designed to measure the material’s attenuation dose rate and a number of static tests were conducted at the Multiphase Laboratory, Institute of Mechanics, Chinese Academy of Sciences. Three phases of oil-water-gas media were inves- tigated for their possible use to simulate different media volumetric fraction distributions in experimental vessels. Attenuation intensities were measured, and the arithmetic of linear attenuation coefficients and the equations of volumetric fractions were studied. Investigation of an unexpected measurement error from attenuation equations revealed that a modified arithmetic was involved and finally the system achieved acceptable accuracy in experimental research.

Treatment of Non-Small Cell Lung Cancer (NSCLC) Using CT in Combination with a PET Examination to Minimize the Clinical Target Volume of the Mediastinum

OBJECTIVE To decrease radiation injury of the esophagus and lungs by utilizing a CT scan in combination with PET tumor imaging in order to minimize the clinical target area of locally advanced non-small cell lung can-cer, without preventive radiation on the lymphatic drainage area. METHODS Of 76 patients with locally advanced non-small cell lung cancer (NSCLC), 32 received a PET examination before radiotherapy. Preventive radiation was not conducted in the mediastinum area without lymphatic metastasis, which was confirmed by CT and PET. For the other 44 patients, preventive radiation was performed in the lymphatic drainage area. PET examinations showed that the clinical target volume of the patients was decreased on average to about one third. The radiation therapy for patients of the two groups was the same, i.e. the dose for accelerated fractionated irradiation was 3 Gy/time and 5 time/week. The preventive dose was 42 to 45 Gy/time, 14 to 15 time/week, with 3-week treatment, and the therapeu- tic dose was 60 to 63 Gy/time, 20 to 21 time/week, with a period of 4 to 5 weeks. RESULTS The rate of missed lymph nodes beyond the irradiation field was 6.3% and 4.5% respectively in the group with and without PET exami- nation (P = 0.831). The incidence of acute radioactive esophagitis was 15.6 % and 45.5% in the two groups respectively (P = 0.006). The incidence of acute radiation pneumonia and long-term pulmonary fibrosis in the two groups was 6.3% and 9.1%, and 68.8% and 75.0%, respectively (P = 0.982 and P = 0.547). CONCLUSION The recurrence rate in the lymph nodes beyond the tar-get area was not increased after minimizing the clinical target volume (CTV), whereas radioactive injury to the lungs and esophageal injury was reduced, and especially with a significant decrease in the rate of acute radioactive esophagitis. The method of CT in combination with PET for minimizing the mediastinal CTV is superior to the conventional preventive radiation of the mediastinum.

Study on absorption coefficients of dual-energy γ-rays in determining phase fractions of multiphase flows

This paper discusses the principle and mathematical method to measure the phase fractions of multiphase flows by using a dual-energy gamma-ray system. The dual-energy gamma-ray device is composed of radioactive isotopes of 241Am and 137Cs with emission energies of 59.5 keV and 662 keV respectively. A rational method to calibrate the absorption coefficient was introduced in detail. The statistical error has been analyzed on the basis of the accurate absorption coefficient which enables determination phrase fractions almost independent of the flow regime. Improvement has been achieved on the measurement accuracy of phase fractions.

单纯胼胝体梗死12例分析

目的:探讨单纯胼胝体梗死的临床表现、头部CT、MRI表现及临床预后。方法:回顾性分析12例单纯胼胝体梗死患者的临床表现及影像学资料。结果:单纯胼胝体梗死临床较少见,主要临床表现为高级智能障碍、精神异常、失语、失读、失用、共济失调、偏盲、轻偏瘫、双下肢为重的中枢性瘫痪,胼胝体梗死诊断主要依靠MRI。结论:单纯胼胝体梗死临床较少见,临床表现复杂,MRI是确诊的依据,临床预后好。