Development of Pupillography Using Image Processing

PURPOSE: Pupillary examination is an important objective method to diagnose lesions of the anterior visual pathways. However, errors and faults may easily alter the interpretation and value of the test as it is highly dependent on the examiner's skills. Therefore, we tried to develop a pupillography which is independent of the examiner. METHODS: Hardware composed of a binocularly measuring instrument adapted for an infrared charge coupled device (CCD) was developed. Two arrays of infrared light emitting diodes (LED) were supplied in front of each of the subject's eyes. A microcontroller to modulate these LED was developed, as was software to save and analyze the pupil images. The hardware was able to deliver a light to either eye or to both eyes, and to change the time, frequency, and intensity of the stimulus. The software automatically analyzed the pupil size and location by image processing. Pupil size was calculated continuously. After artifact elimination, the response amplitudes of the pupils were determined for the right and left pupils. RESULTS: Pupillary images of size 320 x 240, at 30 frames/second, were saved and processed to evaluate the change of the actual pupil size and the velocity of pupillary response. CONCLUSIONS: A pupillography to measure, save and analyze the pupillary response using image processing was developed. Further detailed clinical studies with a large number of patients will be required to validate this new method.

Myocardial Protective Effect of Cardioxane for the Myocardial Damage due to Doxorubicin

PURPOSE: To find out the myocardial protective effect of cardioxane for the myocardial damage by doxorubicin. METHODS: Using Eighteen rabbits(2.0-3.2 kg), doxorubicin(30 mg/m2) was injected intravenously once a week in group I(12 rabbits) and cardioxane(600 mg/m2) was injected at 20-30 minutes before doxorubicin administration in group II(6 rabbits). After this, we operated on the rabbits when the total cumulative dose of doxorubicin was reached at 210, 240, 270 and 300 mg/m2 and observed the degree of myocardial damage with light and electronic microscope. RESULTS: In group I, rabbits with less than 210 mg/m2 of total cumulative dose of doxorubicin, there was no definite myocardial damage but with 240 mg/m2, focal degenerative change was observed and with 300 mg/m2, severe degenerative change was detected with light microscopic examination. With electronic microscope, rabbits with less than 180 mg/m2 of total cumulative dose of doxorubicin in group I, there was no evidence of myocardial damage. In 210 mg/m2, focal degenerative change was detected. With 240 mg/m2, degenerative change was much more advanced and with 300 mg/m2, severe degenerative change was detected. In group II, no definite myocardial damage was observed even though the total cumulative dose of doxorubicin reached 300 mg/m2, but with 360 mg/m2, there was a focal area where myocardial fibers were somewhat decreased, but it's difficult to say whether these decrement were due to adriamycin in the electronic microscopic examination. CONCLUSION: Cardioxane have a good protective effect for the doxorubicin induced cardiomyopathy and it will be used safely in pediatric cancer patients.

Magnetic Resonance Imaging and Histologic Findings of Acute and Subacute Stage of Experimental Cerebral Fat Embolism in Cats

PURPOSE: To determine the magnetic resonance imaging (MRI) findings and natural history of cerebral fat embolism in a cat model, and to correlate the MRI and histologic findings. MATERIALS AND METHODS: Using the femoral arterial approach, the internel carotid artery of 11 cats was injected with 0.1 ml of triolein. T2-weighted (T2WI), T1-weighted (T1WI) and Gd-enhanced T1-weighted (Gd-T1WI) images were obtained serially at 2 hours, 1 and 4 days and 1, 2 and 3 weeks after embolization. Any abnormal signal intensity (SI) was evaluated. After MR imaging at 3 weeks, brain tissue was obtained for light microscopic (LM) examination using hematoxylin-eosin and Luxol fast blue staining, and for electron microscopic (EM) examination. The histologic and MRI findings were correlated. RESULTS: At 2 hours, lesions showed high SI at T2WI, iso- or low SI at T1WI, and strong enhancement at Gd-T1WI. The high SI seen at T2WI decreased thereafter, and most lesions became iso-intense. At week 3, however, small focal areas of high SI were seen in the grey matter of eight cats and in the white matter of three. The low SI noted at acute-stage T1W1 subsequcntly became normal, though in the areas in which T2W1 had depicted high SI, focal areas of low SI remained. Lesion enhancement demonstrated by Gd-T1WI decreased continuously from day 1, and at week 3, weak enhancement was seen at the margin of the remained hypointense lesions in the gray matter in five cats. At LM examination with hematoxylin-eosin staining revealed normal histologic findings in the greater park of an embolized lesion. Cystic change was observed in the gray matter of eight cats, and in the gray and white matter of three of the eight. At LM examination, Luxol fast blue, staining demonstrated demyelination around the cystic change occurring in the white matter, and EM examination of the embolized cortex revealed sporadic intracapillary fat vacuoles (n=11) and disruption of the blood-brain barrier (n=4). Most lesions were normal, however, and perivascular interstitial edema and cellular swelling were mild compared with the control side. CONCLUSION: Experimental cerebral fat embolism was clearly demonstrated by T2WI and Gd-T1WI images obtained at all time points. The greater part of an embolized lesion showed reversible findings at MR and histologic examination; irreversible focal necrosis was, however, observed in gray and white matter at week 3.

Diffusion- and T2-weighted MR Imagings of Cerebral Infarction in Rabbit: Time Course of Imaging Findings and Histologic Correlation

PURPOSE: To correlate the serial findings obtained by diffusion- and T2-weighted imaging with histologicfind-ings obtained from 30 minutes to 31 days after the development of cerebral infarction in rabbits. MATERIALS AND METHODS: Nineteen male New Zealand white rabbits were subjected to intracerebral embolic infarction.Diffusion- and T2-weighted imagings were performed at 30 min, 2, 4 and 6 hours, and 1, 3, 5, 7, 11, 21 and 31days. Apparent diffusion coefficient (ADC) ratios and T2 signal intensity ratios of infarcted and normal brainwere calculated. Microphotographic or electron microscopic (EM) examinations were performed during hyperacute,acute and chronic infarctions. RESULTS: During hyperacute infarction, diffusion-weighted images showed highsignal intensity in the infarcted area, and ADC ratios ranged from 0.81 to 0.56. High signal intensity ondiffusion-weighted images continued until day 3, decreasing thereafter. The ADC ratio increased continuouslyafter day 1. High signal intensity on T2-weighted images was noted from 6 hours and continued until day 7,decreasing thereafter. Microphotographic findings at 6 hours were normal, but EM examination revealed cellularswelling with intact basement membrane, suggesting cytotoxic edema. During acute infarction, abnormal dilatationof the perineural space, cell destruction, and loosening of the neuropil matrix were revealed bymicrophotography. During chronic infarction, microphotographic and EM findings revealed liquefaction necrosis. CONCLUSION: These data indicate that in cases of hyperacute infarction, diffusion-weighted images reflectcy-totoxic edema more accurately than do T2-weighted images. A gradually increasing ADC ratio during the course ofinfarction may be associated with vasogenic edema and cell lysis.