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Biomedical subjects

S Noma

Publications and source records attributed to S Noma.

At least 55 records · Page 3Linked to original sources
PubMed1989

Gamna-Gandy bodies of the spleen: evaluation with MR imaging.

The authors retrospectively evaluated magnetic resonance (MR) images obtained in 64 patients with portal hypertension. Multiple low-intensity nodules were noted within the spleen in eight patients. In all eight cases, these nodules were most apparent on images obtained with the GRASS (gradient-recalled acquisition in the steady state) technique, which is known to be more sensitive to heterogeneity of the magnetic susceptibility, usually caused by hemosiderin deposition. In one of these cases, ultrasonography demonstrated diffuse hyperechoic spots that had been reported to represent Gamna-Gandy bodies of the spleen (ie, organized hemorrhage caused by portal hypertension). Although there was no pathologic proof in their series, the authors believe these low-intensity nodules seen on MR images may represent the hemosiderin deposits of Gamna-Gandy bodies.

Adult↗
PubMed1989

[Magnetic resonance imaging of the thorax].

We examined thirty-five patients with various chest diseases with cardiac gated Magnetic Resonance Imaging (MRI) at 1.5 tesla. Major advantages of MRI of the thorax are its abilities to display sagittal and coronal planes and to disclose vessels clearly without contrast media. We conclude MRI is useful in evaluating, 1) masses at the lung apex or base, 2) chest wall invasion, 3) hilar and mediastinal lymphadenopathy, 4) aortic aneurysm, and 5) bronchogenic cyst.

Adult↗
PubMed1988

The effect of ionic contrast medium on the movement of acutely ischemic and nonischemic canine myocardium.

Regional function assessed by ventriculography may be influenced by the hemodynamic effects of rapidly injecting ionic contrast medium. The importance of this after acute coronary occlusion was examined in eight open-chest, anesthetized dogs. The left anterior descending artery was ligated while sonomicrometric segment lengths in the ischemic (IZ) and nonischemic zones (NZ) were measured. Sodium methylglucamine diatrizoate (Renografin-76, 1 ml/kg) was rapidly injected over 3 seconds. Fifteen minutes later, the left ventricular end-diastolic pressure (LVEDP) was rapidly increased to the level reached during injection. Injecting the contrast increased the LVEDP (7.3 +/- 2.5 to 20.1 +/- 2.9 mm Hg, p less than 0.0001) to the same extent as raising LVEDP (7.6 +/- 2.5 to 10.1 +/- 2.9 mm Hg, p less than 0.0001). Injecting the contrast medium increased IZ total percent systolic shortening (% delta L) (-3.90 +/- 4.43% to -2.68 +/- 4.77%, p less than 0.001) by decreasing isovolumic bulging (-6.68 +/- 4.09% to -5.49 +/- 3.33%, p less than 0.001) with little change in ejection % delta L. NZ total % delta L tended to increase (19.03 +/- 6.53% to 19.94 +/- 6.27%, p = 0.015) because of augmented ejection % delta L (13.12 +/- 2.51% to 13.71 +/- 3.10%, p = 0.017) by the Starling mechanism. Increasing the LVEDP had the same effect on IZ and NZ regional shortening as injecting contrast. Thus regional shortening after acute coronary occlusion is affected by the changes in loading conditions with ionic contrast ventriculography.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Adenomyosis: diagnosis with MR imaging.

Magnetic resonance (MR) imaging characteristics of adenomyosis were studied in eight women (aged 37-49 years) who underwent hysterectomy, and detailed radiologic/pathologic correlation was conducted in all cases. Adenomyosis produced diffuse and smooth uterine enlargement. The extent of the lesion was clearly identified on images obtained with long repetition time and long echo time; a diffuse, low-intensity area accompanied by tiny high-intensity spots was seen subjacent to the endometrium. The area appeared as a localized or diffuse thickening of the junctional zone because it was often isointense with this zone. Pathologic examination confirmed that the extent of adenomyosis correlated well with the low-intensity region on MR images and that both hemorrhagic areas and nonbleeding endometrial tissue corresponded to the high-intensity spots. The lesion consisted of distorted and compacted smooth muscle cells, but microscopic studies failed to explain the definitive difference in intensity between areas of adenomyosis and myometrium.

Adult↗
PubMed1988

Thyroid masses: MR imaging and pathologic correlation.

The authors explored the capability of high-field-strength surface coil magnetic resonance (MR) imaging in disclosing the gross pathologic characteristics of thyroid masses (especially pseudocapsular and hemorrhagic degeneration). Twenty-four patients were examined, including 12 with papillary carcinoma, eight with adenoma, and four with adenomatous goiter. All patients underwent surgery within 2 days after MR imaging. Specimens were cut and correlated directly with MR images. The appearance of the pseudocapsule was classified into four types: A, intact and even thickness around the tumor; B, only partially present or even absent; C, intact but with uneven thickness; D, partially destroyed by tumor. MR imaging findings corresponded precisely with those of gross pathologic examination in all cases but four of adenoma. Type A pseudocapsules were found only in adenoma and type D only in papillary carcinoma. Although the number of cases in the series was limited, the authors conclude that MR images reflect gross pathologic findings well and that some characteristic findings are suggestive of benign or malignant disease.

Adenoma↗
PubMed1988

Spinal arteriovenous malformation: MR imaging.

Ten patients with spinal arteriovenous malformations (AVMs) were examined with high-field-strength (1.5-T) magnetic resonance (MR) imaging and a surface coil (eight patients) or head coil (two patients). Four AVMs were intramedullary, and six were extramedullary. There was one case of Foix-Alajouanine disease (subacute necrotizing myelitis; thrombosed AVM). Three important pathologic findings--myelomalacia, total thrombosis, and wall thickening of the draining vein--were clearly demonstrated at MR imaging and confirmed at autopsy. A flow-sensitive sequence was valuable in the depiction of one intramedullary AVM as hyperintense, the postoperative evaluation of AVM, and the differentiation of nidus from old intramedullary hematoma. In other AVMs, cord edema, periradicular hematoma, and reversible changes of cord scalloping after surgery were demonstrated. MR imaging demonstrated various pathologic changes of the spinal cord that could not be detected with any other imaging method.

Adult↗
PubMed1988

Augmentation of contraction in remote nonischemic zone during acute ischemia.

We studied how left ventricular loading conditions and the size of the ischemic zone affect regional segmental shortening (% delta L) in ischemic (IZ) and remote nonischemic zones (NZ) after acute coronary occlusion. Distal and proximal portions of the left anterior descending artery (group I, 10 dogs) or the left circumflex artery (group II, 10 dogs) were occluded in two stages. Segment length sonomicrometers were placed in the distal and proximal IZ and in the distal and proximal NZ. % delta L was divided into isovolumic and ejection phases. Left ventricular end-diastolic pressure (LVEDP) was decreased 3 +/- 1 mmHg by blood withdrawal and then increased 6 +/- 2 mmHg by blood transfusion before and after distal and proximal coronary occlusions. LVEDP was brought back to its initial value before distal and proximal coronary occlusions. Regional blood flow and total blood flow deficit were measured with microspheres. Similar results were obtained in group I and II experiments. After coronary occlusion, the IZ showed systolic bulging occurring primarily in isovolumic systole. In the NZ, total and isovolumic % delta L increased from control, whereas ejection % delta L did not change. As LVEDP was raised, IZ isovolumic bulging decreased and ejection % delta L was unchanged, whereas NZ isovolumic % delta L decreased and ejection % delta L increased. Thus IZ bulging and NZ isovolumic % delta L changed in opposite directions when load was varied. The larger IZ after proximal coronary occlusion tended to increase the amount of NZ isovolumic % delta L. In conclusion, at low LVEDP NZ augmentation is predominantly caused by an increase in isovolumic % delta L, whereas if LVEDP is increased it is because of an increase in ejection % delta L. In addition, in open-chest animals augmented contraction in the NZ may be related to the size of the IZ.

Acute Disease↗
PubMed1988

The effect of changes in afterload on systolic bulging.

It has been previously shown that after acute coronary occlusion, the extent of systolic bulging is dependent on preload and the function of the remote nonischemic myocardium is influenced by the motion of the ischemic myocardium as well as by the loading conditions. To examine the isolated effects of changing afterload on the movement of acutely ischemic and nonischemic myocardium, seven open-chest, anesthetized dogs were paced from the left atrium at a rate of 100 beats/min after crushing of the sinus node. The pulmonary artery was perfused artificially and the left ventricular end-diastolic pressure (LVEDP) was carefully controlled with a right heart bypass system. Twenty minutes after occlusion of the left anterior descending artery, the peak left ventricular pressure (LVP) was adjusted to three levels (70, 90, and 110 mm Hg) by blood withdrawal or aortic constriction, while the LVEDP was kept constant (8.3 +/- 2.3 mm Hg). Segment length in the ischemic (IZ) and nonischemic zones (NZ) were measured with sonomicrometers and total, isovolumetric, and ejection systolic shortening (% delta L) were calculated. Changes in left ventricular minor-axis diameter were measured with diameter crystals. Increasing the peak LVP increased the LVP both at aortic valve opening and closing. To keep the LVEDP constant as peak LVP was increased, the cardiac output had to be decreased (p less than .0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Endometrial cysts of the ovary: MR imaging.

Magnetic resonance (MR) images of 15 cases of ovarian endometrial cyst were reviewed. With a high-field-strength (1.5-T) MR imager, T1- and T2-weighted images were obtained in axial and sagittal planes, with 5-mm section thickness. MR findings highly suggestive of an endometrial cyst included adhesions to the surrounding organs (e.g., loss of clear margin of the uterine body and tethered appearance of the rectum); a distinct low-intensity zone surrounding a cyst loculus on both T1- and T2-weighted images produced by a thick fibrous capsule; loculus contents with short T1 and long T2 values, attributed to hemorrhagic fluid; and prominent low intensity (shading) within a loculus on T2-weighted images, the mechanism of which is yet to be determined.

Adult↗
PubMed1987

Hepatocellular carcinoma: MR imaging.

Sixty patients with hepatocellular carcinoma (HCC) were studied with computed tomography (CT) and magnetic resonance (MR) imaging at 1.5 T. MR imaging was equivalent to CT in detection of HCC. MR imaging was superior to CT in demonstrating the details of tumors, especially pseudocapsules. In 58 cases, main tumors were detected with MR imaging. On spin-echo (SE) 600/25 (repetition time msec/echo time msec) sequences, tumors were hyperintense in 18 cases, isointense in ten, and hypointense in 30. On SE 2,000/60 sequences, all but two tumors had high signal intensity. Pseudocapsules, intratumoral septa, daughter nodules, and tumor thrombi, which are important characteristics of HCC, were demonstrated in 22, three, six, and six cases, respectively, on MR imaging. MR imaging is useful for characterizing the internal architecture of HCC.

Adult↗
PubMed1987

Moyamoya disease: MR imaging.

Eleven patients with moyamoya disease were studied with magnetic resonance (MR) imaging performed with a high-field-strength (1.5-T) superconducting magnet. In all cases a fundamental pathologic change of moyamoya disease--occlusion or stenosis of the terminal portion of the internal carotid artery and the proximal portion of anterior and middle cerebral arteries--was clearly demonstrated. The characteristic collateral network from the suprasellar cistern to the basal ganglia, which corresponds to the "moyamoya vessels" on angiograms, was seen in several patients. Various ischemic changes, including infarction, brain atrophy, and ventricular dilatation, were also well demonstrated. MR imaging plays an important role in the diagnosis of moyamoya disease.

Adolescent↗
PubMed1987

Thyroid gland: MR imaging.

Magnetic resonance (MR) imaging was performed in eight healthy volunteers and 30 patients with histologically and endocrinologically proved thyroid diseases. The use of a surface coil greatly improved spatial resolution, and normal anatomic structures were well demonstrated. In thyroid tumors, the margin, pseudocapsule, and lymph nodes were easily detected. Smooth margins, lobulated margins, and pseudocapsules were found in both adenoma and papillary carcinoma, whereas unclear margins were found only in papillary carcinoma. An unclear margin between the tumor and adjacent normal thyroid tissue seemed to reflect an ill-defined tumor border on gross pathologic examination. Metastatic lymph nodes as small as 3 mm were seen. Identification of small vessels enabled detection of dilated vessels in thyroid parenchyma in patients with Graves disease. Hemorrhage (hemorrhagic degeneration) was often found in adenoma, papillary carcinoma, and adenomatous goiter, resulting in variable signal intensity.

Adenoma↗
PubMed1987

Transection of the pituitary stalk: development of an ectopic posterior lobe assessed with MR imaging.

Magnetic resonance (MR) imaging was performed in ten patients with pituitary stalk transection who had idiopathic pituitary dwarfism. Contiguous sagittal T1-weighted images were obtained in all cases, and, in some, axial or coronal images were taken for further evaluation. On MR images, normal anterior and posterior lobes of the pituitary gland can be clearly differentiated because the posterior lobe has a characteristic high intensity on T1-weighted images. In the ten patients, the high-intensity posterior lobe was not seen, but a similar high signal intensity was observed at the proximal stump in seven patients. This high-intensity area is the newly formed ectopic posterior lobe, which secretes antidiuretic hormone just as the posterior lobe would. When the ectopic lobe completely compensates for the impaired posterior lobe, endocrinologic data indicate normal posterior lobe function. However, MR imaging can reveal the transection of the pituitary stalk and formation of the ectopic lobe.

Adolescent↗
PubMed1986

Reversal of depressant effects of propranolol on the left ventricular pump function by nifedipine in dogs with chronic ischaemia.

The aim of this study was to clarify the combined effects of propranolol and nifedipine on the regional wall motion and haemodynamic variables of the heart in dogs with chronic ischaemia. After an injection of propranolol the heart rate and stroke volume significantly decreased (from 128(18) beats X min-1 to 113(12) beats X min-1 and from 15.1(3.1) ml to 12.2(2.6) ml respectively) and the left ventricular end diastolic pressure and systemic vascular resistance in systole increased significantly (from 7.3(1.5) mmHg to 10.0(1.8) mmHg and from 8.61(1.42) kPa X litre-1 X min-1 to 11.80(1.59) kPa X litre-1 X min-1 respectively). In the regional myocardium the end diastolic length increased significantly in both border and normal zones (7(3)% and 4(2)% respectively) and the percentage systolic shortening in the normal zone decreased significantly from 18.0(3.1)% to 15.1(2.9)%. In the border and infarcted zones the percentage systolic shortening or systolic lengthening did not change. The administration of nifedipine resulted in significant decreases in left ventricular systolic pressure and in systemic vascular resistance (from 122(17) mmHg to 105(14) mmHg and from 11.80(1.59) kPa X litre-1 X min-1 to 6.63(1.24) kPa X litre-1 X min-1 respectively) and stroke volume increased to 18.2(4.4) ml. The percentage systolic shortening in the border and normal zones improved significantly to 9.8(3.2)% and 19.2(3.7)% respectively without any change in end diastolic length and left ventricular end diastolic pressure. In the infarcted zone no significant change in systolic lengthening or end diastolic length was seen. Thus impaired left ventricular pump function induced by propranolol was reversed by nifedipine.

Animals↗
PubMed1986

Stripe sign in pulmonary perfusion scintigraphy: central pattern of pulmonary emphysema. Work in progress.

Morphologic changes and ventilation abnormalities in the lung that resulted in the peripheral perfusion stripe (the stripe sign) on pulmonary perfusion scintigrams were studied in six patients. Chest radiographs, computed tomography (CT) scans, and positron emission tomography (PET) scans obtained using N-13 were compared. Although there was no apparent correlation between the presence of the stripe sign and the findings on the chest radiographs, PET scans depicted ventilation abnormalities in all of 11 lung areas with the stripe sign in six patients. In addition, ventilation was affected more severely in the central part of the lung than in the subpleural region in ten of the 11 lung areas. CT scans demonstrated emphysematous changes, with low attenuation values located mainly in the central part of the lung in all four patients examined. The results suggest an intimate relationship between the stripe sign and the central pattern of pulmonary emphysema.

Aged↗