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Biomedical subjects

I Anno

Publications and source records attributed to I Anno.

52 records · Page 3Linked to original sources
PubMed1988

Relationship between MR relaxation time and muscle fiber composition.

The relationship between magnetic resonance (MR) relaxation times and muscle fiber composition was investigated in 16 men, and a high positive correlation was found. Higher proportions of fast-twitch fiber were associated with longer relaxation times, indicating that fast-twitch fiber has a longer relaxation time than slow-twitch fiber. Multiple regression analysis, conducted to investigate the suitability of relaxation time as a model of estimating muscle fiber composition, revealed that T1 and T2 were significantly related to muscle fiber composition. These results indicate that MR relaxation time may be used to estimate muscle fiber composition.

Adult↗
PubMed1986

[CT findings in acute spinal epidural hematoma caused by a ruptured cavernous angioma].

A case of acute spinal epidural hematoma due to the rupture of cavernous angioma is reported. A 68-year-old man was admitted to our hospital with a complaint of hematoemesis. After the successful treatment of bleeding from a gastric ulcer by using endoscopical method, he noticed severe motor weakness in his lower extremities. Complete paraparesis of his lower limbs, total sensory loss below the level of fifth thoracic vertebrae, and bladder disturbance were revealed on neurological examination. A metrizamide myelogram showed complete block at the level of fourth thoracic vertebrae. A computed tomography (CT) scan disclosed a dorsolateral heterogeneous high density area (92 Hounsfield Unit) on the right with displacement of the spinal cord to the left, extending from the level of second to fifth thoracic vertebrae. He was operated thirty hours after the onset. After the laminectomy, an epidural hematoma covering over the dural sac was recognized. Following the removal of the hematoma, a hemorrhagic mass was disclosed and removed successfully. A pathological examination revealed cavernous angioma. His symptoms improved partially in three months after the operation. There have been thirteen cases of non-traumatic spinal epidural hematoma which had been diagnosed by CT scan, as far as we are aware. Although only four cases out of 13 were diagnosed without using any contrast materials, we stress that the spinal epidural hematoma can be diagnosed only by plain CT scan because of its characteristic clinical feature, attenuation coefficient, and mass effect to the spinal cord.

Aged↗
PubMed1979

Various manifestations of stratification phenomenon during intravenous cholangiography.

The authors classify various types of stratification phenomenon during intravenous cholangiography. The stage of gallbladder opacification in the recumbent position has been classified as (I) mottled, (II) dendritic, (III) ring-like, and (IV) homogeneous. 'Dendritic' type of stratification phenomenon has never been reported in the literature to our knowledge. At 20 min following infusion of contrast material homogeneous opacification of the gallbladder was noticed in only 14% of patients. The others fell into types I, II or III of stratification phenomenon. In contrast, 87% of the opacified gallbladders were homogeneous on the after fatty meal film. It is therefore mandatory for diagnosis that either a 24 h film or a fatty meal film be taken to avoid the stratification phenomenon.

Cholangiography↗
PubMedDate not supplied

Hepatic tumors: magnetization transfer MR imaging with gadolinium enhancement.

Thirty patients with 15 hepatocellular carcinomas, 10 metastases, four hemangiomas, and one cholangiocarcinoma underwent magnetic resonance imaging at 1.5 T with T1-weighted, T2-weighted spin-echo (SE) images, gradient-echo (GRE) magnetization transfer (MT) images, and gadolinium-enhanced T1-weighted SE and MT-GRE images. The MT effect and lesion-liver contrast-to-noise ratio (C/N) were calculated and visual assessment (qualitative analysis) performed for unenhanced and enhanced MT-GRE images and enhanced T1-weighted SE images. The C/N values for hepatic adenocarcinomas (seven metastases and one cholangiocarcinoma) and hemangiomas were larger for enhanced MT-GRE images (adenocarcinoma, 8.4 +/- 2.3 [P < .01]; hemangioma 24 +/- 2.1 [P < .05]) than for enhanced GRE images (5.0 +/- 1.9 and 18 +/- 2.7, respectively). These enhancing tumors had the highest scores in the qualitative analysis. Enhanced MT-GRE images showed no advantage for depiction of hepatocellular carcinomas relative to the other images.

Adenocarcinoma↗
PubMedDate not supplied

Leptomeningeal angiomatosis accompanied by hair follicle nevus.

A 5-day-old male infant with leptomeningeal angiomatosis accompanied by hair follicle nevus and congenital alopecia is reported. Admitted for frequent left hemiconvulsions, he had three small papular lesions around his right eye and ipsilateral alopecia from the frontal to parietal areas. Histopathological examination of the papular lesions revealed crowding of hair follicles. There were no other skin lesions and no ophthalmic abnormalities. Ictal EEG showed a theta burst in the right parietal area. Computed tomography of the brain revealed cerebral atrophy and a slightly high intensity lesion in the right parietal and occipital lobes with calcification. Gyriform enhancement was demonstrated by contrast MRI in these areas. The pathogenesis is discussed. This case may represent a previously unknown neurocutaneous syndrome.

Alopecia↗
PubMedDate not supplied

PACS and the reporting system. Present status of PACS in the University of Tsukuba.

In the University of Tsukuba, PACS research is being carried out with a special emphasis on the reporting system. The radiological diagnostic system in Japan is not sufficiently developed and the number of diagnostic radiologists in Japan is not as large as in many European countries (M. Akisada, Present status of PACS activities in Japan. Med. Inform. 13 (1988) 289-293). With recognition of this fact, PACS research in Japan should also focus on the reporting system. Recently, the first PACS workstation was installed in the Department of Radiology of the University Hospital, but it has not yet been put to clinical use. Reports can be made on this workstation while viewing the properly provided digital images of MR and CT. As to the concepts of the reporting system, there are three important points. The first one is the double check system to maintain the standard quality of diagnostic performance. This system is expected to provide proper training and education to students and young doctors (S.E. Selzer, S.J. Hessel, P.G. Herman et al., Resident film interpretations and staff review. Am. J. Radiol. 137 (1981) 129-133). The second one is to develop a transcriber workstation, through which reports are easily handled as routine work. The last point is to provide a well-organized diagnostic coding system. For this purpose, a modified IRD (Index for Radiological Diagnosis, by the American College of Radiology) is assumed to be one of the best choices.

Computer Systems↗
PubMedDate not supplied

Paroxysmal nocturnal hemoglobinuria: MR findings.

OBJECTIVE: Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic disorder, characterized by hemosiderin deposition in the proximal renal tubules. MATERIALS AND METHODS: We examined six cases of PNH with MRI including gradient echo imaging. RESULTS: On T2- and T2*-weighted imaging a characteristic hypointense pattern was noted in five of six patients with PNH. The extent of the hypointense area roughly correlated with the time elapsed from the latest hemolytic attack. CONCLUSION: T2*-weighted imaging (gradient echo imaging) is superior to T2-weighted imaging in the detection of hemosiderin in the renal cortex because of the higher sensitivity to magnetic susceptibility effect and shorter examination times. On the other hand, reversal of the normal cortical-to-medullary intensity ratio on T1-weighted imaging was not seen in our cases in which we used echo delay times short enough to neglect T2 effects.

Aged↗
PubMedDate not supplied

MRI of muscle strain injuries.

OBJECTIVE: The purpose of our study was to evaluate (a) the characteristics of muscle strain injuries on MRI and (b) the potential of a frequency-selective fat suppression technique for diagnosing such injuries. MATERIALS AND METHODS: Muscle strain injuries in seven athletes were examined by MRI. Spin echo sequences were obtained with and without fat suppression sequences. The absolute values of the contrast-to-noise (C/N) ratios for lesion versus muscle or fat were then compared for both types of images. RESULTS: We obtained two types of characteristic findings for muscle strain. Lesions of the fascia and adjacent muscles showed a characteristic spray-like or fan-like appearance, extending longitudinally from a shared tendon to the muscle belly in five athletes. This finding was better displayed on coronal images. In contrast, lesions inside a muscle showed a diffuse and inhomogeneous appearance in two athletes. The absolute C/N ratios for lesion versus fat and lesion versus muscle were not significantly different for images with and without fat suppression according to the sign test. However, fat-suppressed images revealed subtle abnormalities that were not seen on conventional images. CONCLUSION: Magnetic resonance can provide detailed information on muscle strain injuries, especially when coronal fat-suppressed images are obtained.

Adolescent↗
PubMedDate not supplied

Knee extension and flexion: MR delineation of normal and torn anterior cruciate ligaments.

OBJECTIVE: Our goal was to assess the effect of joint position of semiflexed and extended knees in MR delineation of the anterior cruciate ligament (ACL). METHODS: With a mobile knee brace and a flexible surface coil, the knee joint was either fully extended or bent to a semiflexed position (average 45 degrees of flexion) within the magnet bore. Sets of oblique sagittal MR images were obtained for both extended and flexed knee positions. Thirty-two knees with intact ACLs and 43 knees with arthroscopically proven ACL tears were evaluated. Two observers compared paired MR images of both extended and flexed positions and rated them by a relative three point scale. Anatomic correlation in MR images was obtained by a cadaveric knee with incremental flexion. RESULTS: The MR images of flexed knees were more useful than of extended knees in 53% of the case reviews of femoral attachments and 36% of reviews of midportions of normal ACLs. Compared with knee extensions, the MR images for knee flexion provided better clarity in 48% of reviews of disrupted sites and 52% of residual bundles of torn ACLs. Normal ACL appeared taut in the knee extension and lax in semiflexion. CONCLUSION: Compared with MR images of knees in extension, MR images of knees in flexion more clearly delineate the femoral side of the ligament with wider space under the intercondylar roof and with decreased volume-averaging artifacts, providing superior visualization of normal and torn ACLs.

Adolescent↗
PubMedDate not supplied

MR staging of pelvic endometriosis: role of fat-suppression T1-weighted images.

We examined whether MR can determine the stage of endometriosis according to the scoring system established and revised by the American Fertility Society (r-AFS), a system which is widely used by gynecologists. We also studied the utility of fat suppression T1-weighted images in improving accuracy. Seventeen patients with endometriosis examined by conventional MR were included in this study. All the patients had surgically proved stage III or IV disease. We determined the stage by MR using the following criteria according to the r-AFS system: adnexal masses without normal ovarian tissue were considered deep ovarian lesions, while those with normal tissue were considered superficial. A lack of fat between the lesion and surrounding structures was considered a dense adhesion, and hyperintense spots were considered peritoneal implants. The MR scores of patients with and without fat suppression were correlated with the surgical scores. MR staging corresponded to surgical staging in 15 of the 17 patients. In eight patients, peritoneal implants of less than 1.5 cm were depicted only by fat-suppression images. However, these lesions did not change the score significantly. MR imaging could determine the stage in advanced endometriosis. Fat-suppression could highlight smaller implants. These tiny lesions had little clinical meaning in these advanced cases; however, the clinical value of this technique should be evaluated in milder disease.

Adipose Tissue↗