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Biomedical subjects

N Kume

Publications and source records attributed to N Kume.

At least 109 records · Page 6Linked to original sources
PubMed1997

Three-dimensional surface displays of perfusion SPET in the evaluation of patients with pulmonary emphysema for thoracoscopic lung volume reduction surgery.

A modified, three-dimensional display was applied to 99Tcm-macroaggregated albumin (99Tcm-MAA) SPET to help assess the effect of thoracoscopic lung volume reduction surgery (LVRS) on regional lung perfusion. Surface-rendered three-dimensional images for 99Tcm-MAA and xenon-133 (133Xe) equilibrium (EQ) SPET were obtained in 11 patients with pulmonary emphysema before and after LVRS. A single three-dimensional fusion display of both images was then reconstructed, and the perfused lungs were transparently visible through the lung contours delineated by the three-dimensional 133Xe EQ image. The extent of preserved perfusion in the lung (the perfusion index) was estimated using the ratio (%) of the total pixel numbers of the segmented perfusion data to those of the 133Xe lung volume data. The three-dimensional fusion display provided an overview of the distribution of hypoperfusion in the lungs with geometric realism and enhanced the perception of anatomic size and configuration compared with multiple tomograms and three-dimensional perfusion images without superimposition of three-dimensional 133Xe image. Post-operatively, it displayed restored perfusion in the remaining lungs, and changes in the perfusion index correlated with %FEV1 (r = 0.731, P = 0.0001) more closely than the perfusion data alone (r = 0.593, P < 0.01). This method is useful for directing LVRS and assessing its effectiveness, as it provides precise tomographic information on regional perfusion.

Aged↗
PubMed1997

Visualization of frontal postural hypoperfusion in patients with Takayasu arteritis with upright 99Tcm-HMPAO brain SPET.

Takayasu arteritis is a chronic inflammatory angiopathy involving the cerebral arteries. We performed upright and supine 99Tcm-HMPAO brain single photon emission tomography (SPET) to investigate the cerebral perfusion pattern in eight patients with Takayasu arteritis, and we compared the results with those acquired using 123I-IMP and acetazolamide in six patients. SPET images were evaluated visually and semi-quantitatively. Hypoperfusion was visually detected in all eight patients during the provocative upright test with 99Tcm-HMPAO, and in three of six tested using acetazolamide and 123I-IMP. Semiquantitative analysis revealed that the mean cortical-to-cerebellar ratio in the upright position was significantly changed compared to that in the supine position in the right frontal area (from 0.86 +/- 0.07 to 0.91 +/- 0.09; P < 0.05). Change was also seen in the left frontal area (from 0.85 +/- 0.08 to 0.91 +/- 0.08; P < 0.05). No significant change was seen in other cortical areas with the upright test or in any areas with the acetazolamide test. We postulate that reduced arterial compliance may cause frontal postural hypoperfusion in patients with Takayasu arteritis due to poor functioning of autoregulation and arterial stenosis or occlusion. We conclude that the provocative upright test with 99Tcm-HMPAO brain SPET can detect abnormal patterns of cerebral perfusion in patients with Takayasu arteritis that might be missed by brain SPET using 123I-IMP and acetazolamide.

Acetazolamide↗
PubMed1997

Ventilation abnormalities in obstructive airways disorder: detection with pulmonary dynamic densitometry by means of spiral CT versus dynamic Xe-133 SPECT.

PURPOSE: To evaluate pulmonary dynamic densitometry (PDD) by means of spiral computed tomography (CT) for detection of ventilation abnormalities in obstructive airways disorders compared with dynamic xenon-133 single photon emission CT. MATERIALS AND METHODS: Eight-second spiral CT was performed during two to three respiratory cycles in six healthy volunteers, 19 patients with airways disorder, and six patients with restrictive lung disease. The data sets were reconstructed as 36 1-second temporally overlapping images at 0.2-second intervals, and regional PDD curves were displayed. Regional ventilation was assessed by means of Xe-133 clearance time. RESULTS: Normal lungs showed smooth, sinusoidal PDD curves with maximal amplitude in lung attenuation change (MALAC) of 54.9 HU +/- 24.5, whereas lungs with obstructive airways disorders with prolonged Xe-133 clearance showed significantly diminished MALAC (31.6 HU +/- 20.1, P < .0001), accompanied by irregularity, asynchronous phase, and deterioration of normal ventral-to-dorsal gradients in MALAC and lung attenuation. Lungs with restrictive diseases without prolonged Xe-133 clearance did not show statistically significant reduction in MALAC. In a total of 251 lung regions, regional MALAC correlated inversely with Xe-133 clearance time (r = -.842). CONCLUSION: PDD by means of spiral CT is acceptable for the detection of ventilation abnormalities in obstructive airways disorder.

Adult↗
PubMed1997

P-selectin and vascular cell adhesion molecule-1 are focally expressed in aortas of hypercholesterolemic rabbits before intimal accumulation of macrophages and T lymphocytes.

The accumulation of monocyte/macrophages and T lymphocytes in arterial intima is a hallmark of early atherogenesis. To investigate the temporal relationships between endothelial expression of adhesion molecules (eg, P-selectin and vascular cell adhesion molecule-1 [VCAM-1]) and intimal accumulation of macrophages and T lymphocytes, immunostaining was performed by using serial frozen sections from intercostal branch points of thoracic aortas of New Zealand White rabbits that had been fed a 0.3% cholesterol diet. After 1 week of cholesterol feeding, neither macrophages nor T lymphocytes were detected, although endothelial expression of P-selectin and VCAM-1 was observed. After 3 weeks, macrophages were detectable in 75% and T lymphocytes were present in 25% of the rabbits. Expression of P-selectin and VCAM-1 was sustained until 10 weeks. Infiltration of T lymphocytes was restricted in areas in which macrophages were accumulated and did not appear to precede macrophage infiltration. E-selectin expression was not detectable before accumulation of mononuclear leukocytes; however, very few endothelial cells covering foam cell lesions expressed E-selectin after 6 weeks. Similar results were obtained in Watanabe heritable hyperlipidemic rabbits aged 1, 2, and 3 months. Taken together, localized expression of P-selectin and VCAM-1 may play a key role in the initial recruitment of macrophages and T lymphocytes in early atherogenesis.

Animals↗
PubMed1997

Lysophosphatidylcholine increases expression of heparin-binding epidermal growth factor-like growth factor in human T lymphocytes.

Atherosclerotic lesions contain substantial numbers of activated T lymphocytes in addition to monocytes/macrophages. T cell-derived cytokines and growth factors may play a role in atherogenesis; however, stimuli responsible for T-cell activation in atherogenesis have not been fully elucidated. In this study, we provide evidence that lysophosphatidylcholine (lyso-PC), a polar phospholipid component increased in atherogenic lipoproteins and atherosclerotic lesions, can upregulate gene expression and secretion of heparin-binding epidermal growth factor-like growth factor (HB-EGF) in cultured T lymphocytes isolated from human peripheral blood. Effects of lyso-PC on T lymphocytes appear to be selective and specific, since lyso-PC also increases interleukin (IL)-2 receptor expression but does not affect mRNA levels for IL-2 or IL-4. Lyso-PC-induced upregulation of HB-EGF and IL-2 receptor mRNA in peripheral T cells is mostly dependent on exogenous IL-2 in conditioned medium. The effect of lyso-PC on HB-EGF induction was more potent in CD4+ cells than in CD8+ cells, although lyso-PC increases IL-2 receptor expression dramatically in both CD4+ cells and CD8+ cells. Lyso-PC similarly increased HB-EGF expression in Jurkat cells, a cell line for human CD4+ T lymphocytes. These results in vitro suggest that lyso-PC may be an important stimulus for T cells in atherogenesis in vivo to upregulate HB-EGF and that T cell-derived smooth muscle growth factors may modulate atherosclerotic progression.

Biological Assay↗
PubMed1997

Hyperventilation technetium-99m-HMPAO brain SPECT in moyamoya disease to assess risk of natural childbirth.

We report a pregnant 19-yr-old patient with moyamoya disease who had undergone bilateral superficial temporal artery to middle cerebral artery anastomosis and encephalomyosynangiosis at 8 yr with an uneventful postoperative course and who desired natural delivery after becoming pregnant at 18 yr. We determined her cerebral vascular reserve since natural delivery can result in decreased cerebral blood flow during labor. Technetium-99m-HMPAO brain SPECT, with hyperventilation challenge, was performed to assess cerebral vascular reserve since the stress of hyperventilation was thought likely to rehearse that of labor. The brain SPECT images, obtained using 333 MBq 99mTc-HMPAO, revealed maintenance of cerebral vascular reserve. In addition, whole-body images including the 27-wk-old fetus were obtained. These images demonstrated accumulation in the fetal liver. Natural delivery was, thus, considered indicated for this patient, who subsequently delivered a healthy baby girl. Technetium-99m-HMPAO brain SPECT with hyperventilation challenge was useful for estimating cerebral vascular reserve and for determining whether natural delivery was indicated for this patient with moyamoya disease.

Adult↗
PubMed1996

Relationship between thallium-201 uptake and tumour proliferative ability in thyroid nodules.

To evaluate whether thallium-201 scan can reflect tumour proliferative activity in thyroid nodules. We compared the degree of 201Tl uptake with the tumour proliferative ability as assessed immunohistochmically by the labelling index of proliferating cell nuclear antigen (PCNA) in malignant and benign thyroid nodules. The case material comprised ten benign and 31 malignant surgically resected nodules from a total of 41 patients. 201Tl scan was performed 5 min (early scan) and 2h (delayed scan) after intravenous injection of 74 MBq of 201Tl. The degree of 201Tl uptake was visually divided into three grades [from (-) to (++)], as compared with its uptake in normal adjacent thyroid tissue. Immunohistochemical staining of PCNA was performed using a monoclonal antibody for PC10 on paraffin-embedded specimens. On both the early and the delayed scans, the mean PCNA index in the nodules with an intense 201Tl, i.e. (++), was significantly higher than that in nodules with a lower or with negative 201Tl uptake. The correlation was higher on the delayed 201Tl scan (P=0.009) than on the early scan (P=0.019). Our results indicate that 201Tl uptake may reflect the tumour proliferative activity of thyroid nodules, and this is especially true with regard to the uptake on delayed scans.

Biomarkers↗
PubMed1996

Superimposition of In-111 platelet SPECT and CT/MR imaging in intracardiac thrombus.

An initial attempt to superimpose in-111-labeled platelet SPECT over CT/MRI in two patients with intracardiac thrombus is presented. One patient was a 65-year-old woman with a history of mitral and tricuspid valve replacement. This patient had a large thrombus measuring 74 x 43 x 34 mm in the right atrium. Fusion imaging with CT showed increased in-111 activity on the surface of the thrombus, which was visualized as circular activity on a planar image. The other patient was a 72-year-old woman who had a thrombus measuring 17 x 14 x 12 mm at the cardiac apex. Planar imaging showed two discrete areas of abnormal in-111 activity. Superimposition of the SPECT image over MR revealed that one of these areas corresponded to the small thrombus, whereas the other related to a previous subendomyocardial biopsy. In both patients, the activity ratio of the abnormal in-111 accumulation versus the cardiac chamber on SPECT was greater than that on planar images. The correlation of in-111 platelet SPECT and CT/MRI was useful in accurately localizing the intracardiac thrombus.

Aged↗
PubMed1996

Vasoreactive effect of acetazolamide as a function of time with sequential PET 15O-water measurement.

The accurate assessment of vascular flow reserve is crucial for the evaluation of risk among patients with cerebrovascular disease. In six patients with unilateral occlusion of the internal carotid artery and one patient with unilateral occlusion of the middle cerebral artery (mean +/- S.D. age = 68 +/- 3 years), we measured cerebral blood flow (CBF) after the administration of 940 MBq 15O-water using a remotely controlled power injector. Studies were performed at rest, after 10 min, and then 10, 20 and 30 min after the administration of 1 mg acetazolamide to evaluate the vasoreactive effect, as reflected by an increase in CBF. Sixteen regions of interest (ROIs) were drawn over the CBF images. These ROIs were as follows in each hemisphere: Area I, four areas in the cortical middle cerebral arterial territory (superior frontal, frontal, temporal and parietal areas); Area II, four areas of the deep middle cerebral and vertebral arterial territory (occipital area, basal ganglia, thalamus and cerebellum). Taking normalized resting CBF to be 100%, the mean CBF measured 10, 20 and 30 min post-injection using sequential positron emission tomography was as follows: Area I, 141.4 +/- 16.3, 127.7 +/- 15.3 and 128.2 +/- 17.4% for non-occluded sites and 116.3 +/- 22.8, 112.7 +/- 16.4 and 114.9 +/- 17.1% for occluded sites; Area II, 143.4 +/- 14.5, 126.2 +/- 10.4 and 125.0 +/- 12.9% for non-occluded sites and 141.9 +/- 28.9, 126.0 +/- 20.5 and 124.1 +/- 17.1% for occluded sites. A significant difference in mean CBF was noted between the non-occluded and occluded sites in Area I, the most marked difference of 25.1% being observed 10 min after the administration of the acetazolamide. We conclude that for an accurate assessment of vascular reserve in patients with cerebrovascular disease, CBF should be measured 10 min post-administration of the acetazolamide.

Acetazolamide↗
PubMed1996

[Attempt of helical CT densitometry for assessing regional pulmonary ventilation].

Pulmonary dynamic CT densitometry during steady-state breathing was recorded and analyzed using helical CT scan in 14 patients with obstructive disorders involving small and large airways, and 2 with restrictive lung disease. The data set of 7-second, continuous helical scan at constant table position were reconstructed as 35 one-second temporarily overlapping images at 0.2- second intervals over 2-3 respiratory cycles, and regional CT densitometry was displayed. Normal lungs (5 volunteers) showed a regular sinusoidal curve, and maximal lung density change (LDC) was greater independent lungs than in independent lungs, with an average difference of 29.5 HU, indicating the gravitational effect In contrast, a regular sinusoidal curve was not shown in obstructive disorders, and a significant reduction in maximal LDC (33.7 +/- 22.6 HU) compared with the normal lungs (60.8 +/- 25.9 HU) (P < 0.001) was indicated. In contrast, no marked reduction in maximal LDC (53.7 +/- 28.6 HU) was shown in restrictive disorders. This method is fast and easy, and appears useful for the detection of ventilation abnormalities in obstructive lung disorders.

Absorptiometry, Photon↗
PubMed1996

Iodine-123-MIBG imaging in pheochromocytoma with cardiomyopathy and pulmonary edema.

We encountered a patient with pheochromocytoma associated with a catecholamine-induced cardiomyopathy that developed recurrently bilateral and unilateral pulmonary edema. The diagnosis of pheochromocytoma was made by elevated plasma catecholamine levels and the intense tumor [123I]MIBG uptake and was confirmed at the time of surgery. The patient showed reduced myocardial [123I]MIBG uptake with left ventricular dysfunction, and endomyocardial biopsy findings were consistent with the diagnosis of catecholamine-induced cardiomyopathy. After tumor resection, plasma levels of catecholamine were normalized, and pulmonary edema never recurred, although cardiac dysfunction did not show an improvement on echocardiography. Myocardial and lung [123I]MIBG uptake increased when compared to uptake levels on preoperative scans, but myocardial uptake was still below normal. These findings indicated that over-secreted catecholamines influenced both the heart and lungs. Pheochromocytoma can induce cardiac and lung injuries, and [123I]MIBG scanning may contribute not only to tumor characterization but also to assessing and monitoring the influence of catecholamines on the heart and lungs.

3-Iodobenzylguanidine↗
PubMed1996

Dynamic pulmonary SPECT of xenon-133 gas washout.

UNLABELLED: A triple-detector SPECT data acquisition mode of "continuous repetitive rotation acquisition" was applied to dynamic pulmonary SPECT with 133Xe gas. METHODS: Subjects included 7 healthy volunteers, 22 patients with a space-occupying mass lesion, 22 with obstructive lung disease and 10 with restrictive lung disease. Following rebreathing of 133Xe, equilibrium and washout SPECT images during spontaneous breathing were acquired every 30 sec for 5-7 min. Regional 133Xe washout was assessed by the real half-time (T1/2) and mean transit time (MTT) images. RESULTS: SPECT and MTT images represented a gravity-induced gradient of ventilation in normal lungs and detailed the distribution of heterogeneous 133Xe washout in patient's lungs with or without abnormalities on chest x-ray CT. The T1/2 (111.4 +/- 26.4 sec) and its coefficient of variation (0.36 +/- 0.13) in obstructive lung diseases were significantly different from those (56.8 +/- 3.9 sec and 0.16 +/- 0.15) in restrictive lung diseases (p < 0.001, p < 0.05, respectively). Comparison of SPECT and planar studies assessed in 19 patients revealed superiority of SPECT in detecting ventilatory abnormalities and a high correlation of T1/2 between the two studies ( r= 0.977, p < 0.001). CONCLUSION: This modality has excellent potential for elucidating the distribution and nature of ventilatory abnormalities.

Administration, Inhalation↗
PubMed1996

[A case of bilateral adrenal neuroblastomas detected by bone scintigraphy].

A 7-month-old girl, who had been resected the left adrenal neuroblastoma 20 days ago, underwent bone scintigraphy with 90mTc-HMDP to survey bone metastases. The bone scan demonstrated avid uptake in the right adrenal gland, in which 123I-MIBG also accumulated. However, the degree of 123-I-MIBG uptake in the right adrenal gland was not necessary higher compared to that in the normal adrenal glands in 7 patients after resection of hemilateral neuroblastomas. Reviewing the preoperative abdominal CT, a swelling of the right adrenal gland had been overlooked because of the small size of 10 x 12 mm in diameter. The follow-up CT after surgery revealed a more growth of the right adrenal gland, accompanied by reelevation of urine vanilmandelic acid. This patient was thus diagnosed as bilateral neuroblastomas. Because bone scintigraphy frequently shows abnormal uptake in primary neuroblastomas, it has potentially diagnostic value for early detection of bilateral adrenal neuroblastomas.

Adrenal Gland Neoplasms↗
PubMed1995

Regional ventilatory evaluation using dynamic SPET imaging of xenon-133 washout in obstructive lung disease: an initial study.

Regional ventilatory abnormalities in obstructive lung disease were evaluated by dynamic single-photon emission tomography (SPET) of pulmonary washout of xenon-133 (133Xe) gas. The subjects included seven healthy volunteers. 17 patients with obstructive lung disease, and seven patients with restrictive lung disease. Following 6 min of inhalation of 133Xe gas (60-72 MBq/l), equilibrium and subsequent washout SPET images during spontaneous breathing were sequentially acquired every 30 s for 6-7 min, using a triple-head SPET system with the return mode of continuous repetitive rotating acquisition. A gravity-induced gradient of ventilation was demonstrated in the volunteers' lungs. Compared with the normal subjects, all the patients with obstructive disease showed abnormal 133Xe retention on the washout SPET images, with or without abnormalities on chest X-ray computed tomography, whereas the patients with restrictive disease did not show any significant delays in washout. This modality may assist in the evaluation of the three-dimensional dynamic process of ventilatory abnormalities in obstructive lung disease.

Adult↗
PubMed1995

Abnormal extrapulmonary accumulation of 99mTc-MAA during lung perfusion scanning.

We present fourteen patients with an abnormal extrapulmonary accumulation on lung perfusion scintigraphy with 99mTc-macroaggregated albumin (MAA), who were examined during the last decade. These included six patients with lung cancer, four with pulmonary arterio-venous fistula, two with congenital heart disease, one with inferior vena cava (IVC) syndrome and one with congenital bronchogenic cyst. All six patients with lung cancer had superior vena cava (SVC) syndrome, and the tumor invaded the thoracic wall. As causes of abnormal accumulation, fourteen patients had a right-to-left shunt, and one patient with IVC syndrome had a systemic vein-to-portal vein shut, and one patient with lung cancer associated with superior vena cava (SVC) syndrome had both right-to-left and systemic vein-to-portal vein shunts. In the two patients with systemic vein-to-portal vein shunts, a hot spot was observed at the hepatic hilum, and radionuclide venography revealed remarkably developed collateral pathways to the portal vein. An extrapulmonary accumulation seen on 99mTc-MAA lung perfusion scan therefore indicates the existence of unusual hemodynamics with a shunt. We should therefore be careful not to overlook this peculiar finding.

Adult↗