Glomangiopericytoma of the Spinal Cord.

Glomangiopericytoma, also referred to as a hemangiopericytoma-like tumor or sinonasal type hemangiopericytoma, is a rare tumor of the nasal cavity and paranasal sinus that has never been reported in the spinal cord. Here, we report a case of a 47-year-old man who developed glomangiopericytoma in the thoracic spine. This lesion showed a heterogeneous high signal intensity compared to the spinal cord on a T2-weighted image and an easily enhanced isointense signal on a T1-weighted image.

Comparison of the image qualities of filtered back-projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction for CT venography at 80 kVp.

PURPOSE: To evaluate the subjective and objective qualities of computed tomography (CT) venography images at 80 kVp using model-based iterative reconstruction (MBIR) and to compare these with those of filtered back projection (FBP) and adaptive statistical iterative reconstruction (ASIR) using the same CT data sets. MATERIALS AND METHODS: Forty-four patients (mean age: 56.1 ± 18.1) who underwent 80 kVp CT venography (CTV) for the evaluation of deep vein thrombosis (DVT) during 4 months were enrolled in this retrospective study. The same raw data were reconstructed using FBP, ASIR, and MBIR. Objective and subjective image analysis were performed at the inferior vena cava (IVC), femoral vein, and popliteal vein. RESULTS: The mean CNR of MBIR was significantly greater than those of FBP and ASIR and images reconstructed using MBIR had significantly lower objective image noise (p < .001). Subjective image quality and confidence of detecting DVT by MBIR group were significantly greater than those of FBP and ASIR (p < .005), and MBIR had the lowest score for subjective image noise (p < .001). CONCLUSION: CTV at 80 kVp with MBIR was superior to FBP and ASIR regarding subjective and objective image qualities. KEY POINTS: • MBIR provides superior image quality compared with FBP and ASIR • CTV at 80kVp with MBIR improves diagnostic confidence in diagnosing DVT • CTV at 80kVp with MBIR presents better image quality with low radiation.

Intramuscular sparganosis in the gastrocnemius muscle: a case report.

Sparganosis is a parasitic infection caused by the plerocercoid tapeworm larva of the genus Spirometra. Although the destination of the larva is often a tissue or muscle in the chest, abdominal wall, extremities, eyes, brain, urinary tract, spinal canal, and scrotum, intramuscular sparganosis is uncommon and therefore is difficult to distinguish from a soft tissue tumor. We report a case of intramuscular sparganosis involving the gastrocnemius muscle in an elderly patient who was diagnosed using ultrasonography and MRI and treated by surgical excision. At approximately 1 cm near the schwannoma at the right distal sciatic nerve, several spargana worms were detected and removed.

Baker's Cyst with Intramuscular Extension into Vastus Medialis Muscle.

Baker's cysts are one of the most common cystic lesions around the knee joint and mainly caused by fluid distension of the gastrocnemius-semimembranous bursa that is situated along the medial side of the popliteal fossa. Typically, a Baker's cyst extends along the intermuscular planes around the knee joint and may enlarge any direction. However, it is mostly located in the inferomedial or superficial layers of the knee joint and less commonly extends laterally or proximally. Expansion of the cyst tends to respect the intermuscular planes, and Baker's cysts along the intramuscular route have been rarely reported. Thus, we report a case of Baker's cyst with intramuscular extension into the vastus medialis muscle.

Hepatocellular carcinoma supplied from the short gastric artery: treatment with chemoembolization.

We report a case of transcatheter arterial chemoembolization (TACE) to treat hepatocellular carcinoma (HCC) that was supplied by the short gastric artery. A 67-year-old woman with two nodular HCCs underwent repeated TACE. One of the nodules was supplied by the short gastric artery.

Subungual tumors: clinicopathologic correlation with US and MR imaging findings.

Various types of tumors can affect the subungual space, including benign solid tumors (glomus tumor, subungual exostosis, soft-tissue chondroma, keratoacanthoma, hemangioma, lobular capillary hemangioma), benign cystic lesions (epidermal and mucoid cysts), and malignant tumors (squamous cell carcinoma, malignant melanoma). Imaging plays an important role in the detection and differentiation of subungual tumors because of their small size, nonspecific clinical manifestations, and functional significance. Ultrasonography (US)-in particular, high-resolution US with color Doppler studies-provides useful information regarding tumor size, location, shape, and internal characteristics (cystic, solid, or mixed), but it is limited in the further characterization of tissue. Magnetic resonance (MR) imaging has an important role in categorizing tumors according to their anatomic location, pathologic origin, and signal characteristics. There is some overlap between the US and MR imaging features of subungual tumors; however, certain features can allow accurate diagnosis and expedite management when correlated with clinical and pathologic findings.

MRI of the cat brain in the study of vascular permeability after intraarterial carotid injection of triolein.

BACKGROUND: Triolein emulsion embolization into the carotid artery depicts reversible increased vascular permeability that can promote the effect of chemotherapy or can reduce the amount of chemotherapeutic drugs for equivalent effectiveness. PURPOSE: To establish the minimum dosage of 0.5% triolein for studying vascular permeability changes in a triolein emulsion model. MATERIAL AND METHODS: Sixty-six cats were divided into six groups based on the amount of emulsified triolein (0.5%) infused into the carotid artery: group 1 (n=12, 6 ml/kg), group 2 (n=12, 4.5 ml/kg), group 3 (n=12, 3 ml/kg), group 4 (n=10, 1.5 ml/kg), group 5 (n=10, 1 ml/kg), and group 6 (n=10, 3 ml/kg of saline (control group)). T1-weighted, T2-weighted, and post-contrast T1-weighted MRI was performed 2 h after the infusion of the triolein emulsion. Contrast enhancement ratios (CERs) were obtained with pre- and post-contrast T1-weighted images in the ipsilateral and contralateral hemispheres. Signal intensity ratios (SIRs) of the ipsilateral and contralateral hemispheres were evaluated on T2-weighted images. After removal of the brain tissues, edema ratios in the ipsilateral and contralateral hemispheres were obtained from wet versus dry brain weights. Data were statistically evaluated by analysis of variance, followed by the Tukey honestly significant difference test to compare the difference in the mean CER of the ipsilateral and contralateral hemispheres, mean SIR on T2-weighted image, and mean edema ratio between each group when overall significance was attained. RESULTS: In the ipsilateral hemispheres, the difference in the CER between the control group and groups 1 (P=0.004), 2 (P=0.043), and 3 (P=0.008) were statistically significant. The difference in the CERs between the triolein emulsion groups was not statistically significant (P>0.05). The T2-weighted SIRs were significantly different between the control group and groups 1 (P=0.027) and 2 (P=0.004). However, the edema ratios of all doses in the triolein emulsion groups showed no significant differences compared with the control group. CONCLUSION: The minimum dosage of 0.5% triolein emulsion to achieve increased vascular permeability in the hemisphere in cat brains appears to be 3 ml/kg. This minimum dosage of triolein emulsion can be useful for acquiring basic data in further studies of vascular permeability changes in a triolein emulsion model.

Extraforaminal with or without foraminal disk herniation: reliable MRI findings.

OBJECTIVE: The purpose of our study was to evaluate spinal MR images for extraforaminal disk herniation with or without foraminal disk herniation to determine the reliable MRI findings. MATERIALS AND METHODS: Thirty-five patients with extraforaminal with or without foraminal disk herniation confirmed at radiculography or surgery between March 2005 and July 2007 underwent spinal MRI. We assessed the morphologic features of the disk, changes in nerve root thickness, epidural fat obliteration surrounding the nerve root, and displacement of the nerve root in the foraminal and extraforaminal zones. RESULTS: Mixed disk herniation was found in 23 patients, and purely extraforaminal herniation was found in 12 patients. Focal eccentricity of the disk contour was identified in 32 patients (91%). Change in the nerve root thickness was found in 30 patients (86%). The nerve roots were displaced in 22 patients (63%), and the original location was maintained in nine patients (26%). Differentiation between the disk and the nerve root was poor in four of the 35 patients (11%). Obliteration of the epidural fat surrounding the nerve root was present in all patients. CONCLUSION: The presence of extraforaminal with or without foraminal disk herniation should be ascertained on the basis of the following MRI findings: focal eccentricity of the disk contour, obliteration of epidural fat surrounding the nerve root, change in the thickness of the nerve root, and displacement of the nerve root.

Inactivation of O6-methylguanine-DNA methyltransferase in soft tissue sarcomas: association with K-ras mutations.

The DNA-repair protein O(6)-methylguanine-DNA methyltransferase removes alkyl adducts from the O(6)-position of guanine. The adducts can mispair with T during DNA replication, resulting in a G-to-A mutation. Epigenetic inactivation of O(6)-methylguanine-DNA methyltransferase has been found in human neoplasia and is considered one of the implicated factors in chemoresistance. Sixty-two patients with soft tissue sarcomas were analyzed with regard to the status of O(6)-methylguanine-DNA methyltransferase protein expression status using immunohistochemistry and promoter hypermethylation of the MGMT gene using methylation-specific PCR. G-to-A transitions in codons 12 and 13 of the K-ras oncogene were investigated using PCR and direct automated sequencing analysis. A loss of O(6)-methylguanine-DNA methyltransferase expression was noted in 20 (32.3%) cases of 62 total soft tissue sarcomas. The MGMT promoter hypermethylation rate was 33.9% (21/62 cases). Of the 54 sarcomas evaluated, K-ras mutations were found in only 2 (3.7%) cases. Loss of O(6)-methylguanine-DNA methyltransferase expression and MGMT promoter hypermethylation showed a significant association with high American Joint Committee on Cancer stage, high French Federation of Cancer Centers grade, and aggressive behavior. On multivariate analysis, these were not an independently significant prognostic factors. However, when the group receiving chemotherapy was analyzed (n = 27), loss of O(6)-methylguanine-DNA methyltransferase expression was correlated with worse survival on multivariate analysis (P = .024). MGMT promoter hypermethylation status had a strong correlation with loss of O(6)-methylguanine-DNA methyltransferase expression (P = .000). Our results suggest that MGMT promoter hypermethylation and loss of O(6)-methylguanine-DNA methyltransferase expression tend to be associated with poor prognosis and that the loss of O(6)-methylguanine-DNA methyltransferase protein expression frequently occurs via MGMT promoter hypermethylation. However, MGMT promoter hypermethylation was not significantly associated with point mutations of K-ras at codons 12 and 13 in sarcomas.

Sonography of patients with hemiplegic shoulder pain after stroke: correlation with motor recovery stage.

OBJECTIVE: This study was performed to clarify the cause of shoulder pain using sonography and to evaluate the relationship between the sonographic findings and the motor recovery stages in stroke patients with hemiplegic shoulder pain. SUBJECTS AND METHODS: Between March 2005 and January 2007, 71 consecutive stroke patients with hemiplegic shoulder pain underwent shoulder sonography. For comparison, bilateral shoulder joints were evaluated in 20 of the 71 patients. The interpretations of the sonographic findings were based on the findings of previously published studies. Whether a correlation existed between the sonographic findings and the motor recovery stages was determined. RESULTS: Subacromial-subdeltoid (SA-SD) bursal effusion (n = 36) was the most common abnormality seen on sonography. Tendinosis of the supraspinatus tendon (n = 7), partial-thickness tear of the supraspinatus tendon (n = 6), and full-thickness tear of the supraspinatus tendon (n = 2) were also noted. Biceps tendon sheath effusion (n = 39) and normal findings without any biceps tendon sheath effusion (n = 13) were detected. Clinicians managed each patient's shoulder pain on the basis of the sonographic findings. No statistically significant correlation was found between the grade of sonographic findings and Brunnstrom stage (p = 0.183). A shoulder with hemiplegia had a higher number of abnormal sonographic findings than a noninvolved shoulder (p = 0.007). CONCLUSION: The cause of shoulder pain was variable and there was no correlation between the stages of motor recovery and the grades of sonographic findings in patients with hemiplegic shoulder pain.

Hepatic capsular and subcapsular pathologic conditions: demonstration with CT and MR imaging.

A variety of pathologic conditions and pseudolesions occur at the capsular and subcapsular regions of the liver and are detected with cross-sectional abdominal imaging. These entities are related to anatomic and hemodynamic characteristics of the liver such as negative subdiaphragmatic pressure, connection with other viscera and extraperitoneal sites by the perihepatic ligaments, and a "third inflow" of blood from sources other than the usual hepatic arterial and portal venous sources. Pathologic conditions can affect the hepatic capsular and subcapsular regions by way of peritoneal, hematogenous, biliary, and perihepatic ligamentous routes. Pseudolesions or benign conditions may also be identified on the basis of altered hemodynamics of the liver. Computed tomography and magnetic resonance imaging with a multiphasic approach can be used to identify and characterize these entities. Familiarity with the wide spectrum of pathologic conditions and pseudolesions at the hepatic capsular and subcapsular regions and precise knowledge of the anatomic and hemodynamic characteristics of the liver will aid the radiologist in diagnosing pathologic conditions and differentiating pseudolesions from true lesions.

A pragmatic protocol for reduction in the metal artifact and radiation dose in multislice computed tomography of the spine: cadaveric evaluation after cervical pedicle screw placement.

OBJECTIVE: To assess the correlation between the metal artifact degree and the tube voltage (in peak kilovolts; kVp) and tube current (in milliamperes; mA) in multidetector row computed tomography (MDCT) and evaluate the proper protocols for reduction in the metal artifact and the radiation dose. METHODS: We performed MDCT examinations for 13 cadavers operated for transpedicular screw insertion from C3 to C7, bilaterally. We used 80, 100, and 120 kVp in all cadavers. For the mA, we arbitrarily applied 100, 150, and 200 in 6 cadavers (experiment 1); 140, 180, and 220 in 4 (experiment 2), and randomly used mAs between 60 and 220 in 3 (experiment 3). The lengths of the artifacts emanating from the anterior and posterior tips of the screw were used for the degree of artifact. RESULTS: In experiment 1, the mA did not significantly affect the metal artifacts (P > 0.05); but the kVp did (P < 0.05). In experiment 2, the mA and kVp did not significantly affect the metal artifact degree (P > 0.05). In experiment 3, the mA did not affect the metal artifacts, but the kVp caused changes in metal artifact degrees (simple quantitative analysis). CONCLUSIONS: The proper parameters for the simultaneous reduction in the artifact and radiation dose are suggested to be tube voltages from 100 to 120 kVp and tube currents lower than the generally used values of 200 to 220 mA.

Gene expression in mixed type liposarcoma.

AIMS: Mixed type liposarcomas are rare. Here, we analysed the characteristics of an unusual case of mixed type liposarcoma, which consisted of a well-differentiated liposarcoma (WDL) and a pleomorphic liposarcoma (PL), with a special emphasis on molecular alterations. METHODS: Microscopic and immunohistochemical approaches were used to investigate this case of mixed type liposarcoma, and to identify molecular alterations in this tumour, gene expression was examined in PL, WDL, and normal adipose tissue (NA) samples using a 17,000 cDNA microarray. RESULTS: The tumour mass, 9 x 5 x 5 cm, was located in the left upper arm of a 76-year-old man. Grossly, the proximal portion of the tumour was composed of a yellowish fatty lesion, whereas the distal portion of the tumour was whitish and necrotic in nature. Histologically, the tumour was composed of two distinct components. The proximal component of the tumour was a WDL and the distal component was a PL. Immunohistochemically, S100 protein immunoreactivity highlighted lipoblasts in both tumour portions. The Ki-67 proliferation index was <1% in the WDL and 20% in the PL. MDM2 was positive in the WDL, but negative in the PL. p53 was negative in both areas. Numerous differentially expressed genes were found, which included genes coding for signal transduction, transcription, cell cycle, enzyme, structural protein, immune system and others. CONCLUSIONS: Our data demonstrate that multiple genes are differentially expressed in mixed type liposarcoma and suggest that these genes are associated with the differences in the morphological characteristics and pathogenesis of mixed type liposarcoma.

Endovascular treatment of a ruptured internal thoracic artery pseudoaneurysm presenting as a massive hemothorax in a patient with type I neurofibromatosis.

We report a case of acute hemothorax caused by a left internal thoracic artery pseudoaneurysm rupture in a patient with neurofibromatosis type I, which was successfully treated with endovascular coil embolization.

A model for research on the blood-brain barrier disruption induced by unsaturated fatty acid emulsion.

PURPOSE: The authors investigated whether fatty acid emulsion affects the blood-brain barrier (BBB), whether disrupted BBB is reversible, and whether the fatty acid emulsion technique may be a model for BBB research. MATERIALS AND METHODS: The fat emulsion was made with 0.05 mL of oleic acid or linoleic acid and 20 mL of normal saline. The internal carotid artery in 14 cats was infused with oleic acid emulsion (group 1) and with linoleic acid emulsion in 12 cats (group 2). Gd-enhanced T1-weighted (Gd-T1WI), diffusion-weighted (DWI), and additional apparent diffusion coefficient (ADC) map magnetic resonance imaging (MRI) was obtained at 1 hour, 1 and 4 days, and 1 week after infusion. MRI findings were evaluated qualitatively. Quantitatively, the signal intensity ratio (SIR) of the lesion to the contralateral hemisphere was measured on Gd-T1WIs. The SIRs were statistically analyzed using the student t test. The brain tissue was removed immediately for light and electron microscopy examination if the lesion showed no contrast enhancement and was isointense on DWIs and the ADC maps. RESULTS: The lesions appeared at 1 hour in both groups as contrast enhancement on Gd-T1WIs, as isointensity or mild hyperintensity on DWIs, and as isointensity on the ADC maps. On day 1, these MRI findings were decreased in group 1 and were not seen in group 2. At 1 hour, the SIRs of group 1 were significantly higher than those of group 2 (P = 0.016). On day 1, the SIRs of both groups approximated 1.0. Light microscopy findings revealed minor necrosis and demyelination in one cat from group 1 and in 3 cats from group 2. Electron microscopy examinations showed minimal findings in the cortical lesions in groups 1 and 2. CONCLUSIONS: Infusion of unsaturated fatty acid emulsion into the carotid artery of cats revealed vasogenic edema of the brain and reversible changes as depicted on MRI. This unsaturated fat emulsion technique may be used as a model for research on BBB disruption.

Preliminary results of endovascular stent-assisted angioplasty for symptomatic middle cerebral artery stenosis.

BACKGROUND AND PURPOSE: Stent placement for intracranial atherosclerosis has become an alternative treatment technique; however, stent placement for middle cerebral artery (MCA) stenosis remains a technical and clinical challenge. Our purpose was to assess the feasibility, safety, and effectiveness of stent placement for MCA stenosis. METHODS: Between May 1998 and August 2003, we performed stent placement for MCA stenosis (more than 50%) in 17 patients and retrospectively analyzed the technical success rate, complications, and outcomes over 10 months. RESULTS: Stent placement was technically successful in 16 (94.1%) patients and failed in one patient (5.9%), because the stent did not reach the lesion due to carotid artery tortuousity. In 16 patients, postprocedural angiography showed restoration of the normal luminal diameter. Acute in-stent thromboses occurred in nine patients (56.3%) and was lysed with abciximab. The parent artery ruptured in two patients (12.5%): One died from massive subarachnoid hemorrhage, and the other patient received a second stent over the tear site. Stent jumping (distal migration at the time of balloon inflation) occurred in one patient (6.3%) and was solved by implanting a second stent. Periprocedural complications included subacute in-stent thrombosis (n = 1, 6.3%) and minor stroke (n=1, 6.3%); these were relieved with heparin therapy or local thrombolysis. Fifteen patients experienced symptomatic relief or were stable at follow-up. Angiographic follow-up (n=6) revealed no in-stent restenosis. CONCLUSION: Stent placement for symptomatic MCA stenosis was technically feasible and effective in alleviating symptoms and improving cerebral blood flow.

Effect of triolein emulsion on the blood-testis barrier in cats.

PURPOSE: Although the blood-testis barrier (BTB) is beneficial physiologically, it acts as an obstacle to chemotherapy. We wished to determine whether a triolein emulsion could alter the permeability of the BTB in cats. MATERIALS AND METHODS: An emulsion of 0.05-mL triolein in 20 mL of saline was infused into the abdominal aorta just proximal to the branching of the renal arteries of each of 15 cats (embolic group). As controls, 12 cats were each similarly infused with 20 mL of normal saline (control group). Pre and postcontrast MR images were obtained 30 minutes and 2 hours after embolization. The images were analyzed for the presence and degree of contrast enhancement (qualitative analysis), and the contrast enhancement ratios (CER) derived from one testis of each animal were compared and statistically analyzed by the mixed linear model (quantitative analysis). RESULTS: Contrast enhancement of the testis was observed in both groups at both time points, but it was more prominent in the embolic group. The CERs in the embolic group (0.63 at 30 minutes, 0.42 at 2 hours) were significantly higher than in the control group (0.36 at 30 minutes, 0.28 at 2 hours; P = 0.0001). In each group, the CERs at 2 hours were significantly lower than those at 30 minutes (P = 0.006). CONCLUSION: Intra-arterial infusion of triolein emulsion increased the permeability of the BTB. This result may be useful in future studies of BTB disruptions caused by fat emulsions.

Magnetic resonance imaging and histologic findings of experimental cerebral fat embolism.

RATIONALE AND OBJECTIVES: The purpose of this study was to determine whether cerebral fat embolism demonstrated reversible or irreversible findings in magnetic resonance (MR) imaging over time and to compare the features in MR images with histologic findings in a cat model. MATERIALS AND METHODS: MR images were obtained serially at 2 hours, 1 and 4 days, and 1, 2, and 3 weeks after embolization with 0.05 mL of triolein into the internal carotid artery in 19 cats. Any abnormal signal intensity and change in the signal intensity were evaluated on T2-weighted images, T1-weighted images, diffusion-weighted images (DWIs; including apparent diffusion coefficient [ADC] maps), and gadolinium-enhanced T1-weighted images (Gd-T1WI) over time. After MR imaging at 3 weeks, brain tissue was obtained and evaluated for light microscopic (LM) examination using hematoxylin-eosin and Luxol fast blue staining. For electron microscopic examination, the specimens were obtained at the cortex. The histologic and MR findings were compared. RESULTS: The embolization lesions showed hyperintensity on T2-weighted images, hyperintensity, or isointensity on DWIs, hypointensity, or isointensity on ADC maps and contrast enhancement on Gd-T1WIs at 2 hours. The T2-weighted hyperintensity extended to the white matter at day 1 and decreased thereafter. Contrast enhancement decreased continuously from day 1, and hyperintensity on DWI decreased after day 4. Hypointensity on ADC maps became less prominent after day 4. By week 3, most lesions had reverted to a normal appearance on MR images and were correlated with LM findings. However, small focal lesions remained in the gray matter of 8 cats and in the white matter of 3 cats on MR images, and this correlated with the cystic changes on LM findings. Electron microscopic examination of the cortical lesions that reverted to normal at week 3 in MR images showed that most of these lesions appeared normal but showed sporadic intracapillary fat vacuoles and disruption of the endothelial walls. CONCLUSIONS: The embolized lesions of the hyperacute stage were of 2 types: type 1 lesions, showing hyperintensity on DWIs and hypointensity on ADC maps, have irreversible sequelae, such as cystic changes; whereas type 2 lesions, showing isointensity or mild hyperintensity on DWIs and ADC maps, reverted to a normal appearance in the subacute stage.

Experimental cerebral fat embolism: embolic effects of triolein and oleic acid depicted by MR imaging and electron microscopy.

BACKGROUND AND PURPOSE: In fat embolism, free fatty acid is more toxic than neutral fat in terms of tissue damage. We evaluated the hyperacute embolic effects of triolein and oleic acid in cat brains by using MR imaging and electron microscopy. METHODS: T2-weighted imaging, diffusion-weighted imaging, and contrast-enhanced T1-weighted imaging were performed in cat brains after the injection of triolein (group 1, n = 8) or oleic acid (group 2, n = 10) into the internal carotid artery. MR images were quantitatively assessed by comparing the signal intensity ratios of the lesions with their counterparts on T2-weighted images, apparent diffusion coefficient (ADC) maps, and contrast-enhanced T1-weighted images. Electron microscopic findings in group 1 were compared with those in group 2. RESULTS: Qualitatively, MR images revealed two types of lesions. Type 1 lesions were hyperintense on diffusion-weighted images and hypointense on ADC maps. Type 2 lesions were isointense or mildly hyperintense on diffusion-weighted images and isointense on ADC maps. Quantitatively, the signal intensity ratios of type 1 lesions in group 2 specimens were significantly higher on T2-weighted images (P =.013)/(P =.027) and lower on ADC maps compared with those of group 1. Electron microscopy of type 1 lesions in both groups revealed more prominent widening of the perivascular space and swelling of the neural cells in group 2, in contrast to notable endothelial defects in group 1. CONCLUSION: MR and electron microscopic data on cerebral fat embolism induced by either triolein or oleic acid revealed characteristics suggestive of both vasogenic and cytotoxic edema in the hyperacute stage. Tissue damage appeared more severe in the oleic acid group than in the triolein group.