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Objective To describe CT and MRI imaging findings of retinal hamartomas with tuberous sclerosis and evaluate their clinical value. Design Retrospective case series. Participants 7 patients of tuberous sclerosis complex (TSC) who have ocular lesions found with CT and MRI examination. Methods 7 patients with tuberous sclerosis were diagnosed by clinical data and head CT. The size, morphology, density and enhancing situation of the retinal lesions were observed with CT and MR.I, as while as with direct or indi-rect fundoscopy. Main Outcome Measures CT and MRI features of ocular lesions. Results 7 cases displayed intraeranial calcification and/or non-calcified tubercles, situating in subendyrna (7 cases, accounting for 100%) by head CT. Orbital CT and MRI showed 4 cases (57.1%) of flat retinal hamartomas 3 cases (42.9%) 9f retinal lobular and nodular hamartomas, 2 cases(28.6%) scattered calcification patches in hamartoma, and 2 cases (28.6%) of nanophthalmos. The lesions displayed unenhancement on contrast-enhanced MR images in 7 cases(100%) . There was 1 case (14.3%) of progressive retinal astrocytic hamartoma. Conclusion The examination of CT and MRI may find the bigger retinal hamartomas, which can play a very important role at the diagnosis with the help of whole brain examination. For progressive retinal nstrocytic hamartoma,systemic evaluation with CT and MRI can provide evidence for choosing appropriate thera-pies. (Ophthalmol CHN, 2009, 18: 257-260)
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Objective To investigate the CT perfusion imaging and the pathological features on the disturbance of regional cerebral microcirculation in a pre-infarction period, and to evaluate the relationship between the astrocytes and regional cerebral microcirculation. Methods Dynamic CT perfusion imaging of the models with regional cerebral hypoperfusion and astrocytic swelling in rats was performed to assess the presence or absence of the disturbance of regional cerebral microcirculation. Then, the histopathologic examination was made for both models, respectively. The ratios of side-to-side were measured at hypoperfusion areas in the models of regional cerebral ischemia. Results Regional hypoperfusion was revealed by regional cerebral blood flow (rCBF) and mean transit time (MTT) maps in the group of hypoperfusion for 6 hours. Regional cerebral blood volume (rCBV) and time-to-peak (TTP) maps were normal in that group. The ratios of rCBF, rCBV, MTT and TTP were 0 39-0 55, 0 92-1 00, 1 20-1 50 and 1 00-1 00 respectively. Astrocytic swelling pressing the capillary wall was obvious and subtle neuronal reversible degeneration was occasionally found. TTC stain was normal. In the tACPD group of astrocytic swelling, the abnormal hemodynamic regions on rCBF and MTT maps were found. The rCBV maps of 3 rats in the tACPD group showed the area of reduced rCBV. In 2 rats of tACPD group, the areas of delayed TTP were also found. The ratios of rCBF, rCBV, MTT and TTP were 0 25-0 44, 0 70-1 01, 1 20-2 00 and 1 02-1 45 respectively. TTC stain was negative. Electron microscope study revealed remarkable swelling of astrocytes, especially endfoot processes of astrocytes around capillaries. The abnormal hemodynamic region on rCBF and MTT maps matched with abnormal extent on histopathologic examination. The rCBV and TTP maps appeared normal. Conclusion The astrocytes can react in a way faster than the neurons in the pre-infarction period, viz. astrocytic swelling. The swelling of astrocytic foot, which pressed capillary vessel, induced the disturbance of regional cerebral microcirculation, and then aggravated hypoxic ischemic state in regional brain parenchyma. Perfusion CT and its parameters' analysis may play an increasing role to delineate the reversible hypoperfusion areas in pre-infarction period. Analyzing the relationship of rCBF and rCBV is very helpful to know the status of the capillary vessels in regional cerebral hypoperfusion area.
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Objective To assess the diagnostic value of delayed CT contrast enhancement patterns in hilar cholangiocarcinoma based on two phased dynamic incremental CT scanning. Methods Fifty two patients with suspected hilar tumor and bile duct obstruction underwent spiral CT scan. The scan time for one revolution of the X ray tube was 1 second. To elucidate the delay time for optimal imaging, all proved cholangiocarcinoma with delayed (6、8、10、15、20、30 minutes) post equilibrium phase contrast enhanced CT scans were acquired with unenhanced, dynamic contrast enhanced, and delayed images. Degree of delayed enhancement was compared with that of surrounding liver parenchyma. Results (1) 8～15 minutes after IV injection of contrast material was the delay time for optimal imaging. (2) Of 29 cholangiocarcinomas, the early CT showed hypoattenuating (lower than that of liver parenchyma) in 23 tumors, isoattenuating (equal to that of the liver) in 4 tumors, and hyperattenuating (higher than that of liver) in 2 tumors. The delayed CT scan showed isoattenuating in 8 tumors, hyperattenuating in 21 tumors, and no hypoattenuating. Most of delay imaging of hilar cholangiocarcinoma may appear hyperattenuating ( U=-4.307 3, P
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Objective To establish a stable and controllable model of acute regional cerebral ischemia in rats, and to evaluate it by CT perfusion imaging and histological study. Methods Twenty eight male Wistar rats were randomly divided into 4 groups, and there were 7 rats in each group. The sham operation rats were defined as the first group, rats suffered from cerebral ischemia for 15 minutes were classified as the second group, rats suffered from cerebral ischemia for 30 minutes and then reperfusion for 1 hour as the third group, and rats suffered from hypo perfusion for 6 hours as the fourth group. Cerebral ischemia or hypo perfusion were induced by inserting a nylon thread of different diameter into right middle cerebral artery (MCA) of rats under the monitoring of regional cerebral blood flow (rCBF) by the Laser Doppler Blood Perfusion Monitor (BPM). rCBF was also examined by dynamic CT perfusion imaging. At the end of the observation time, rats were decapitated, and three rats of each group were performed 2,3,5 triphenyltetrazolium chloride (TTC) staining and four rats were performed histological study. Results In the second group, rCBF was controlled within 5% to 22% under the monitoring by BMP and CT perfusion imaging showed the decreased rCBF in 7 rats, but TTC staining showed red appearance indicating no infarction focus formed. Electronic microscopic study revealed astrocytic swelling and a few of neuronal degeneration. In the third group, rCBF was controlled within 4% to 23% under the monitoring by BMP. There were more severe astrocytic swelling and a lot of neuronal degeneration. The abnormal areas in CT perfusion images were the same as TTC staining. In the fourth group, in accordance with less decrease ment of rCBF (from 38% to 55%) in 7 rats, there were obvious astrocytic swelling and subtle neuronal degeneration. TTC stain did not show ischemia area. All these abnormal changes were not observed in the sham operation rats. Conclusion The controllable acute regional cerebral ischemic model in rats is very stable and repeatable. It can be simulated into the ischemic state of different perfusion level. This model is suitable for the research of acute cerebral infarction and regional cerebral ischemia. The facts that parallel changes existed among BMP measurement, CT perfusion imaging, and brain histology indicated that CT perfusion imaging is accurate and sensitive in evaluating acute regional ischemia.
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Objective To describe CT and MRI imaging findings of retinal hamartomas with tuberous sclerosis and evaluate their clinical value.Design Retrospective case series.Participants 7 patients of tuberous sclerosis complex(TSC) who have ocular lesions found with CT and MRI examination.Methods 7 patients with tuberous sclerosis were diagnosed by clinical data and head CT.The size,morphology,density and enhancing situation of the retinal lesions were observed with CT and MRI,as while as with direct or indirect fundoscopy.Main Outcome Measures CT and MRI features of ocular lesions.Results 7 cases displayed intracranial calcification and/or non-calcified tubercles,situating in subendyma(7 cases,accounting for 100%) by head CT.Orbital CT and MRI showed 4 cases (57.1%) of flat retinal hamartomas 3 cases(42.9%) of retinal lobular and nodular hamartomas,2 cases(28.6%) scattered calcification patches in hamartoma,and 2 cases(28.6%) of nanophthalmos.The lesions displayed unenhancement on contrast-enhanced MR images in 7 cases(100%).There was 1 case(14.3%) of progressive retinal astrocytic hamartoma.Conclusion The examination of CT and MRI may find the bigger retinal hamartomas,which can play a very important role at the diagnosis with the help of whole brain examination. For progressive retinal astrocytic hamartoma,systemic evaluation with CT and MRI can provide evidence for choosing appropriate thera- pies.