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Biomedical subjects

M Iio

Publications and source records attributed to M Iio.

At least 55 records · Page 3Linked to original sources
PubMed1990

Regenerating nodules of liver cirrhosis: MR imaging with pathologic correlation.

To determine the pathologic basis for low-intensity nodules seen on MR images of the liver in patients with cirrhosis, we obtained spin-echo and gradient-echo MR images in 20 cirrhotic patients in whom partial hepatectomies were subsequently performed for hepatocellular carcinoma. Low-intensity liver nodules were shown on gradient-echo and spin-echo images in eight patients. Pathologic study of the liver in these patients showed that these nodules were regenerating nodules containing hemosiderin. Low-intensity nodules were seen only on T2-weighted spin-echo images in four other patients. Microscopic examination of the liver in these patients showed regenerating nodules without hemosiderin deposits. Broad fibrous septa containing vascular spaces were present in two of these four patients. These results suggest that regenerating nodules containing hemosiderin or those that are surrounded by vascular fibrous septa are visible on MR images as low-intensity nodules and that gradient-echo images are useful in demonstrating nodules with hemosiderin.

Aged↗
PubMed1990

[Cerebral blood flow and cerebral oxygen metabolism in patients with dementia of frontal lobe type].

This study was designed to investigate the differences in cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) between patients with dementia of frontal lobe type and patients with Alzheimer's disease. Positron emission tomography (PET) using 15O steady state inhalation technique was carried out in 5 patients with a clinical diagnosis of dementia of frontal lobe type and 7 patients with a clinical diagnosis of Alzheimer's disease. CBF and CMRO2 were significantly decreased in the frontal cortex except for precentral region in patients with dementia of frontal lobe type in comparison to those values in patients with Alzheimer's disease. However, in patients with dementia of frontal lobe type CBF and CMRO2 in the parietal cortex and the occipital cortex were relatively preserved when compared with patients with Alzheimer's disease. In comparison with values for CBF and CMRO2 in the posterior part of brain [frontal or temporal/(parietal + occipital)/2 ratio], both values in the frontal cortex were markedly decreased in all 5 patients with dementia of frontal lobe type, but there was no marked reduction in the frontal cortex in patients with Alzheimer's disease. In addition, in 2 patients with dementia of frontal lobe type whose duration of the disease was more than 7 years, CBF and CMRO2 in the temporal cortex were markedly reduced in comparison with values in the posterior part of brain. These results suggested that PET findings of marked reduction in CBF and CMRO2 in the frontal cortex are useful to distinguish dementia of frontal lobe type from Alzheimer's disease.

Adult↗
PubMed1990

[Difference between T1 and T2 weighted MR images in avascular necrosis of the femoral head].

T1 and T2 weighted MR images were compared in 32 hips with avascular necrosis, and the difference between them was discussed. In 27 of 32 hips, abnormal low intensity area in the affected femoral head is smaller in T2 weighted images than in T1 weighted images. The area of low intensity on T1 weighted image and high on T2 weighted image might be granuloma in reactive tissue and surrounding hyperemia. The difference between T1 and T2 weighted images must be taken into consideration especially in determination of the border of affected bone.

Adult↗
PubMed1990

[Thin-section computed tomography of the bronchi; 2. Right upper lobe and left upper division].

Thin (2mm) section contiguous computed tomographic (CT) scans were obtained through the bronchi of the right upper lobe and the left upper division in 30 patients. All segmental bronchi were identified. The right subsegmental bronchi were identified in 100%, and the left subsegmental bronchi in 97%. The type of the orifice of the right bronchus was trifurcated (53%), the extension of B1 was apicoanterior (50%), and the size of B2b was equal to B3a (63%). The extension of the left B3 was subapicoanterior (38%), and the size of B1+2c was equal to B3a (62%).

Adult↗
PubMed1990

[MR imaging of idiopathic transient osteoporosis of the hip].

Four patients with idiopathic transient osteoporosis of the hip were examined by magnetic resonance imaging (MRI). MRI clearly showed low signal intensity in the affected femoral head on T1-weighted images and high signal intensity on T2-weighted images. After regression of hip pain, MR images became normal. MRI was a useful method for diagnosis and follow-up study of idiopathic transient osteoporosis of the hip.

Adult↗
PubMed1990

[Renal lymphoma; six cases].

Six patients had nine kidneys with lymphoma. Five patients (83%) had non-Hodgkin lymphoma, and three (50%) bilaterally. There were multiple nodules in four kidneys (44%). The lesions were changeful in the course. Gallium scintigraphy showed abnormal uptakes. Magnetic resonance imaging was examined in one case. The lesions were hypovascular in the angiographies. Inflammation is one of the different diagnosis.

Adult↗
PubMed1989

[MRI demonstration of pseudolobules of liver cirrhosis--particular reference to iron deposits on autopsy specimens].

MRI was performed on formalin-fixed autopsied liver specimens of nine patients with liver cirrhosis. Tiny low-intensity nodules were demonstrated in four specimens, in which microscopic examination revealed hemosiderin deposits in pseudolobules. In one specimen with mild hemosiderin deposits, low-intensity nodule was not seen on MRI. This result suggests that there is a close relationship between MRI demonstration of low-intensity nodules and iron deposits in pseudolobules of liver cirrhosis.

Adult↗
PubMed1989

Positron emission tomography using pyruvate-1-11C in two cases of mitochondrial encephalomyopathy.

Positron emission tomography (PET) using pyruvate-1-11C was carried out to investigate the in vivo metabolism of pyruvate in the brains of patients with mitochondrial encephalomyopathy and Leigh's disease. Two epileptic patients were studied as control subjects. Radioactivity was eliminated from the brain tissue of the epileptic patients soon after injection of pyruvate-1-11C. PET images of mitochondrial encephalomyopathy patients showed an increase in radioactivity in the cerebral cortex, basal ganglia and thalamus, with elimination of radioactivity being slower than that of epileptic patients. One patient with Leigh's disease showed similar PET images. PET using pyruvate-1-11C is useful for the evaluation of mitochondrial energy metabolism in the brain.

Brain Diseases↗
PubMed1989

Decreased blood flow and oxygen metabolism in the cerebellum, brain stem and thalamus in a case with Menkes kinky hair disease.

Cerebral blood flow and oxygen metabolism were measured in a five-year-old boy with atypical Menkes kinky hair disease (MKHD) by using positron emission tomography (PET). The patient was diagnosed as having atypical MKHD because of low serum and urinary copper levels, and clinical symptoms. The CT revealed mild to moderate degrees of brain atrophy predominantly in the cerebellum. The PET demonstrated marked decreases of cerebral blood flow and oxygen metabolism in the cerebellum, brain stem and thalamus. These findings seem to reflect the neuropathological abnormalities observed in MKHD. PET seems to be more sensitive than CT in detecting abnormalities in the affected structures. However, because this case is atypical the question of whether typical cases show similar features on the PET remains.

Brain Diseases, Metabolic↗
PubMed1989

Hepatic epithelioid hemangioendothelioma: report of five cases.

Results of computed tomography (CT), ultrasonography (US), angiography, and radionuclide imaging were analyzed in five cases of histologically proved hepatic epithelioid hemangioendothelioma (EHE), a rare vascular tumor of adults that has a variable but often long clinical course. All patients received palliative treatment. CT and US were performed repeatedly over a period of up to 53 months. Initial radiologic examination showed two types of hepatic lesions: multiple nodules in both lobes (nodular lesions, n = 2) and large masses with or without calcifications that generally spread along the hepatic margins (diffuse lesions, n = 3). Nodular lesions may be an earlier form of hepatic EHE, as they later gradually changed into the diffuse type. Follow-up CT after treatment showed definite regression of tumors in two cases. In the differential diagnosis, the radiologic findings of diffuse lesions were considered to be specific to hepatic EHE, while those of nodular lesions were nonspecific.

Adult↗
PubMed1989

Cystic neoplasms of the pancreas: comparison of MR imaging with CT.

Cystic neoplasms of the pancreas are divided into two major groups: microcystic adenomas and mucinous cystic neoplasms. Five microcystic adenomas and seven mucinous cystic neoplasms (three cystadenomas and four cystadenocarcinomas) were examined with both magnetic resonance (MR) imaging and computed tomography (CT). The cystic content was differentiated more easily with MR imaging than with CT. It was homogeneous in four of the five microcystic adenomas, all of which had lobulated borders best seen on T2-weighted images. The mucinous cystadenomas and cystadenocarcinomas were all composed of multiple compartments that varied in signal intensity. The septa, shape, and wall thickness were demonstrated on T1- and/or T2-weighted MR images almost as well as on CT scans. Overall, MR imaging was equal or slightly superior to CT in the diagnosis of pancreatic cystic neoplasms, except in its limited ability to demonstrate calcifications of the tumor wall and septa.

Adult↗
PubMed1989

Siderotic nodules in the spleen: MR imaging of portal hypertension.

The authors retrospectively evaluated magnetic resonance (MR) images obtained at 1.5 T in 233 patients with portal hypertension and 91 subjects without it and pathologic findings in four resected spleens (one normal). Multiple, tiny (3-8 mm in diameter), low-intensity spots in the spleen were observed in 21 of 233 patients. Among the imaging studies performed in these 21 patients, the spots were seen on five of 14 T1-weighted images, 11 of 20 proton density images, and 12 of 20 T2-weighted images obtained with spin-echo techniques and on 14 of 14 fast-scan images obtained with gradient-echo rephasing. MR images in the 91 subjects did not show such lesions. MR images of the three spleens resected from patients with portal hypertension showed the low-intensity spots, which corresponded to siderotic nodules found at pathologic analysis. Despite limited pathologic confirmation, siderotic nodules (so-called Gamna-Gandy nodules) are considered the most likely cause of multiple low-intensity spots in the spleen.

Female↗
PubMed1989

MR differentiation of hepatocellular carcinoma from cavernous hemangioma: complementary roles of FLASH and T2 values.

Forty-two patients with hepatocellular carcinoma (hepatoma) and 18 patients with hemangioma were studied with MR imaging at 1.5 T to evaluate the efficacy of single-slice breath-hold FLASH (fast low-angle shot) images in distinguishing between the lesions and to compare with T2 differentiation using conventional spin-echo images. The difference between mean tumor-to-liver signal ratio on FLASH imaging of hepatocellular carcinoma (1.46 +/- 1.06) and hemangioma (0.86 +/- 0.45) was statistically significant (p less than .01). Fifty-one (82%) of 62 lesions were classified correctly when the borderline of tumor-to-liver signal ratio between hepatoma and hemangioma was set at 0.9. The mean T2 values of hepatomas and hemangiomas were 48 +/- 10 msec and 89 +/- 20 msec, respectively. Fifty-seven (92%) of 62 lesions were correctly diagnosed with the T2 borderline of 80 msec. The five misdiagnosed lesions with the T2 borderline were hemangiomas smaller than 2 cm with tumor-to-liver signal ratios less than 0.9. FLASH images appear promising for differentiating between hepatoma and hemangioma, and they complement T2 values in characterizing small lesions.

Carcinoma, Hepatocellular↗
PubMed1989

[Cerebral hemodynamics in multiple cerebral infarction with or without dementia].

Cerebral blood flow and metabolism in 25 patients with multiple cerebral infarcts (14 with dementia) and 5 healthy age-matched controls were measured to investigate the difference in cerebral blood low (CBF) and cerebral oxygen consumption (CMRO2) between patients with dementia and patients without dementia. None of the patients had any lesions in the cortex, but all had multiple lesions in the basal ganglionic region, and in the white matter, according to CT images. CBF, CMRO2 and oxygen extraction fraction were measured by positron emission tomography (PET) using the 15O2, C15O2 steady state inhalational technique. In patients with multiple cerebral infarcts the absolute values of CBF and CMRO2 were decreased significantly from normal control values, and there was no significant difference in the absolute values of CBF and CMRO2 between patients with dementia and patients without dementia. In most patients with dementia, relative values (regional value/mean cortical value) of CBF and CMRO2 decreased in the frontal and the parietal cortex. Four patients had repeated PET studies. In two of them, decrease in CMRO2 was preceded by decrease in CBF. These results suggest that dysfunction of frontal cortex and parietal cortex, and chronic ischemia might be related to the occurrence of dementia in patients with multiple cerebral infarcts, which were in the basal ganglia and the white matter.

Aged↗
PubMed1989

[Computed tomography of postoperative pelvic lymphocele].

Computed tomography (CT) was obtained in seven patients with postoperative pelvic lymphocele. The CT appearance of the lymphocele was nodule or oval cystic mass of low attenuation. Most of lymphoceles located laterally in the external iliac region. They were identified on the first CT, mean 2.5 months after surgery. They became small (2 cases) or disappeared (4 cases, mean 7 months after surgery). Infection was noted in one case, and another patient had lower abdominal pain. One of different diagnoses is recurrence.

Female↗
PubMed1989

[Is T2-weighted imaging reliable in the differential diagnosis of an adrenal mass? Dependence of signal intensity on the size of tumors].

We reviewed T2-weighted images of 41 adrenal tumors. There were 25 adenomas and 16 non-adenomas. We compared the signal intensity of the adrenal tumors with that liver and classified the tumor/liver intensity ratio (TLR) into five categories; very low (much less than), low (less than), iso-intense (=), high (greater than), and very high (much greater than). The size of adenomas in diameter ranged between 8 mm-50 mm. TLR of 92% of adenomas less than 20 mm (13 cases) were (less than) or (=); when adenomas exceeded 20 mm (12 cases), 75% were (greater than) or (much greater than). TLR of non-adenomas all (greater than) or (much greater than).

Adenoma↗
PubMed1989

[MR imaging of the inner ear; findings of Ménière's syndrome].

Symptoms in Ménière's disease are explained by hydrops of endolymphatic system with recurrent ruptures of the membranous labyrinth. The primary cause of the increased endolymphatic volume appears to be an imbalance between secretion and resorption of endolymph which may be due to an obstruction of the endolymphatic duct and sac, located in the vestibular aqueduct. Non-visualization or narrowing of the vestibular aqueduct of the paper have been demonstrated by conventional tomography and high resolution computed tomography (HR-CT). But the endolymphatic duct and sac can not be obtained by HR-CT and conventional tomography. Whereas, on MRI, these are identified. By MRI, we prospectively tried to demonstrate morphological alterations in 10 patients with Ménière's disease and in 4 patients with vestibular neuronitis. These were compared with a group of 20 normal men. Visualization of the endolymphatic duct and sac (vestibular aqueduct) on MRI was assessed. There was a distinctly decreased visualization of the vestibular aqueduct in the Ménière group and vestibular neuronitis group. We were able to confirm a statistically proven usefulness of the MRI technique in identifying an anatomical abnormality which is directly in correlation with the side of the lesion in cases of unilateral Ménière's disease.

Adult↗