Deposition and clearance of inhaled 18FDG powder in patients with chronic obstructive pulmonary disease

As freon is limited in its use as a generator for aerosol inhalation, powder particles are used as an alternative for inhalation therapy. The pulmonary deposition and clearance of inhaled powder particles was studied by positron emission tomography (PET) in ten patients with chronic obstructive pulmonary disease (COPD) and in five normal controls. The powder, 5 microm in mean diameter, was water soluble and labelled with 2-deoxy-2-[18F]-fluoro-D-glucose (18FDG). Powder inhalation was done with single deep inspiration from residual volume to total lung capacity. The initial deposition ratio in the right or left lung field to total inhaled dose, measured by an anteroposterior rectilinear scan, did not differ between normals and COPD patients. Ratios of radioactivity detected within the central and peripheral regions (the central to peripheral ratio) measured by the PET scan was not significantly different between COPD patients (4.8+/-2.6, mean+/-SD) and normals (2.6+/-0.8, mean+/-SD). However, the regional powder deposition in peripheral lung fields measured by the PET scan was significantly more uneven in COPD patients than in normal patients. The clearance rate of 18FDG, defined as the retention ratio of 18FDG activity to the initially deposited 18FDG at 60 and 120 min after inhalation, in the trachea, large bronchi or peripheral lung fields measured by tomographic scan showed a wider variation in COPD patients than in normals. To conclude, inhaled powder tended to be deposited more centrally and was distributed more unevenly in the peripheral lung in chronic obstructive pulmonary disease patients than in normals. This could be a limitation of powder inhalation used for therapy in chronic obstructive pulmonary disease patients.

Cerebral blood flow correlated with carotid blood flow in neurologically normal elderly with severe white matter lesions

Previous studies of white matter signal hyperintensity (WMSH) on T2-weighted MRI (magnetic resonance imaging) have shown it to be related to decreased cerebral blood flow (CBF). However, there have been few studies on the relationship of WMSH and the internal carotid blood flow (CaBF). Doppler ultrasound sonography is widely used for evaluation of CaBF. We analyzed the relationship between CBF, CaBF, and WMSH. The subjects had not suffered cerebral ischemic episodes although they had some risk factors for stroke. They received MRI and were classified into three groups, i.e. mild, moderate, and severe WMSH. The % stenosis of the internal carotid artery (ICA) was measured with angiography. Doppler sonography was used to measure the mean bilateral CaBF. The oxygen-15 steady-state technique and PET (positron emission tomography) were used to measure CBF. There were significant correlations between the % stenosis of ICA and the ipsilateral CaBF and between the % stenosis of ICA and hemispheric CBF. There was a significant relationship between CBF and CaBF in the severe WMSH group, remaining significant after partialling out of the effects of the % stenosis. This indicated that an atherosclerotic change of the cerebral artery occurred in a way that carotid vascular resistence and cerebrovascular resistence were 'proportional'. Copyright Rapid Science Ltd

Endothelial nitric oxide synthase in the endometrium during the menstrual cycle in patients with endometriosis and adenomyosis

OBJECTIVE

To determine the expression of endothelial nitric oxide synthase in the endometrium during the menstrual cycle in endometriosis and adenomyosis.

DESIGN

Immunohistochemical identification of endothelial nitric oxide in endometrial tissues using the monoclonal antibody.

SETTING

Department of obstetrics and gynecology in a university hospital.

PATIENT(S)

The subjects were divided into three groups: 35 patients with endometriosis, 33 patients with adenomyosis proven histologically, and 46 fertile controls.

MAIN OUTCOME MEASURE(S)

Semiquantitative immunostaining (evaluation nomogram) score in endometrial cells.

RESULT(S)

The analyses revealed phase-dependent changes in the expression of endothelial nitric oxide synthase in the surface and glandular epithelia during the menstrual cycle in the fertile controls. The expression was weakest in the early proliferative phase, gradually increased, was most marked in the midsecretory phase, and decreased thereafter. In contrast, stromal cells did not change throughout the cycle. Contrary to expectations, the expression of endothelial nitric oxide synthase in endometriosis and adenomyosis was persistently greater than the control levels throughout the menstrual cycle.

CONCLUSION(S)

This study has shown that endothelial nitric oxide synthase is changed in a phase-dependent manner during the menstrual cycle. The exaggerated expression of endothelial nitric oxide synthase in the endometrium throughout the cycle suggests some pathologic role in endometriosis and adenomyosis.

Parapharyngeal meningioma extending from the intracranial space evaluated by FDG PET

We report a rare case of parapharyngeal meningioma extending from the intracranial space evaluated by PET with [18F]-2-fluorodeoxyglucose (FDG). Although the parapharyngeal meningioma had a high rate of glucose metabolism, it was proved to be pathohistologically benign. The high rate of glucose metabolism of the tumor reflected tumor aggressiveness well because the tumor grew in a relatively short time.

[Hippocampal hypoperfusion underlying dementia due to chronic toluene intoxication]

To elucidate the pathophysiology underlying the dementia due to chronic intoxication of toluene, a positron emission tomography was carried out in a 24-year-old right-handed man who had been sniffing thinner which contains toluene for 6 years. In addition to the cerebellar ataxia and pyramidal signs, this patient exhibited a mental deterioration including recent memory disturbance: verbal IQ was 52, performance IQ was 52 and total score was 51 on WAIS-R. MRI revealed a mild diffuse cortical atrophy, symmetrical hyperintensity lesions in the corticospinal tracts including corona radiata posterior limb of the internal capsule and ventral part of the pons, and hypointensity lesions in the both thalami on T2-weighted images, whereas the changes in the deep white matter was relatively mild on T2-weighted images. In PET, both cerebral blood flow (CBF) and cerebral metabolic rate of oxygen (CMRO2) were diffusely decreased bilaterally, and specifically in both hippocampi, they were reduced as low as 61% of the normal values as obtained from 12 young normal volunteers. Additionally, in the frontal cortex, CBF and CMRO2 were 60% and 71% of the normal values, respectively. Although the dementia due to chronic toluene intoxication has been assumed to be closely related to the degree of the cerebral white matter lesions based on the MR findings, the present results suggest that the mental deterioration including recent memory disturbance seen in the early stage of chronic toluene intoxication is associated with the hypoperfusion and hypometabolism in the hippocampus and frontal limbic system.

Subcortical hypoperfusion associated with asymptomatic white matter lesions on magnetic resonance imaging

BACKGROUND AND PURPOSE

We examined whether hemodynamic and metabolic abnormalities in the cerebral white matter, basal ganglia, and thalamus are associated with asymptomatic white matter lesions (WML) depicted on MR images.

METHODS

A positron emission tomographic study with H2(15)O, C15O, and 15O2 was performed in eight normal control subjects without any WML (mean +/- 1 SD age, 68.5 +/- 10.2 years) and in 15 asymptomatic subjects with WML (71.3 +/- 8.5 years) to measure regional cerebral blood flow (CBF), cerebral blood volume, oxygen extraction fraction (OEF), and oxygen metabolic rate.

RESULTS

In the cerebral white matter in the asymptomatic subjects with WML, significantly lower CBF (20.3 +/- 3.9 mL/100 mL per minute; P < .05) and significantly higher OEF (0.43 +/- 0.08; P < .05) were found compared with those for control subjects (23.5 +/- 2.6 mL/100 mL per minute and 0.37 +/- 0.06, respectively). The severity of WML was not related to the magnitude of hypoperfusion. In the basal ganglia, significantly lower CBF (44.9 +/- 6.9 mL/100 mL per minute; P < .01) and significantly higher OEF (0.54 +/- 0.08; P < .01) were found in the WML group than in control subjects (70.1 +/- 12.0 mL/100 mL/min and 0.39 +/- 0.03, respectively). In the thalamus, there was no significant difference in CBF and OEF between the control and WML groups.

CONCLUSIONS

Hypoperfusion of the cerebral white matter and basal ganglia in asymptomatic WML subjects may be induced by the arteriosclerosis of long penetrating medullary arteries and lenticulostriate arteries but may not be directly related to the production of WML. The role of hypoperfusion in the production of WML and acceleration of its development remains to be elucidated.

Misery perfusion with preserved vascular reactivity in Alzheimer's disease

To elucidate the hemodynamic pathophysiology underlying Alzheimer's disease (AD), cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2) and oxygen extraction fraction (OEF) were measured with positron emission tomography in 10 patients with probable AD and in 20 age-matched normal volunteers. By the 15O intravenous bolus injection method, CBF was measured during resting state, CO2 inhalation (hypercapnia) and hyperventilation (hypocapnia), and the vascular reactivity (VR) was estimated by comparing the CBF changes (delta CBF%/PaCO2 mmHg) in the hyper- or hypocapnic to the resting state. By the 15O2 single-breath method or 15O steady-state method, CMRO2 and OEF were measured during resting state. Based on 26 regions of interest, local CBF, CMRO2 and OEF were compared statistically between the two groups. As compared with the control group, the mean CBF and CMRO2 decreased to as low as 77.0% and 88.4% of the normal values, respectively, while the mean OEF increased by 12.1% (p < 0.05) in AD patients. These changes were most pronounced in the supramarginal and superior temporal gyri. There was no focal change in VR in the AD group, and no significant difference was seen in VR to either hyper- or hypocapnia between AD and control groups. The results may suggest a vascular involvement, possibly at the capillary level, that might cause a relative misery perfusion syndrome accompanied by preserved vascular reactivity in AD.

Regional correlations between the EEG and oxygen metabolism in dementia of Alzheimer's type

To determine the relationship between EEG slowing and cerebral hypometabolism in dementia, 10 patients with dementia of Alzheimer's type (DAT) were evaluated with quantitative topographic EEG and positron emission tomography (PET). Power in each 1-Hz frequency band from 2-20 Hz, power ratio index, and normalised PET data from corresponding cortical sites were compared to data obtained from 20 normal volunteers. PET revealed significant parieto-temporal hypometabolism, and topographic EEG mapping and power spectrum analysis revealed a slowing of the background EEG that was most pronounced in the parietal-temporal areas. Correlation analysis between EEG power spectrum data and CMRO2 revealed significant negative correlations for frequencies below 8 Hz and significant positive correlations above 8 Hz in the parieto-temporal regions, which have previously been identified as the areas most severely affected by pathological changes associated with DAT. Correlation coefficients plotted as functions of frequency illustrated the relationships between EEG changes and reduced CMRO2, supporting previous views that EEG slowing in DAT may be related to hypometabolism in cortical regions most affected by the disease.

Intracarotid recombinant human tumor necrosis factor-alpha reduces cerebral blood flow and methionine uptake in rat brain tumors

The aim of the present study is to understand the therapeutic effects of recombinant human tumor necrosis factor-alpha (rH-TNF) on hemocirculation and metabolism of brain tumors. Using double-label autoradiographic technique, we have monitored changes in regional cerebral blood flow (rCBF) and protein-bound fraction of (3H-methyl)-L-methionine, expressed as acid-insoluble fraction (AIF), in rat brain tumors following treatment with intracarotid rH-TNF. The central portion of tumors showed a significant decrease in rCBF and AIF at 4 hours after the injection (p < 0.01, p < 0.05, respectively, as compared with non-treated control rats), turned microscopically necrotic at 24 hours, and became more extensively necrotic at 72 hours. Tumor cells remained viable only in the peripheral portion of the tumors after the treatment. The peripheral portion also showed a moderate decrease in rCBF, but less change in AIF to 4 to 72 hours after the treatment. Neither ipsilateral nor contralateral non-involved cortex demonstrated appreciable changes in rCBF and AIF during the observed period. Intracarotid rH-TNF selectively reduces tumor rCBF and AIF, resulting in histological modification.

Regional cerebral blood flow measurement with iodine-123-IMP autoradiography: normal values, reproducibility and sensitivity to hypoperfusion

We recently proposed a simplified technique for measuring regional cerebral blood flow (rCBF) using the [123I]N-isopropyl-p-iodoamphetamine (IMP) autoradiographic (ARG) method with SPECT (the IMP-ARG method). We examined normal values of rCBF and the reproducibility and sensitivity to hypoperfusion in stroke patients using this method.

METHODS

By using a standard arterial input, a single static scan, a fixed distribution volume (Vd) and one-point arterial blood sampling, we measured rCBF in 39 normal volunteers (19 men and 20 women; mean ages 61 +/- 11 yr for the men and 60 +/- 12 yr for the women). Eighteen neurologically stable patients with prior stroke (mean age = 65 +/- 11 yr) were studied twice at a mean interval of 97 days. In 16 patients (7 men and 9 women, mean age = 63 +/- 5 yr) with subarachnoid hemorrhage, rCBF was measured 1-2 wk after onset. Cerebral vasospasm was evaluated by repeated angiography. The mean rCBF in the vasospastic area was compared with that in a nonvasospastic area.

RESULTS

The mean rCBFs of the cerebral cortex and centrum semiovale in the volunteers were 33.0 +/- 5.1 ml/100 g/min and 25.0 +/- 4.5 ml/100 g/min, respectively. There was no age-dependent change in rCBF, but the women showed significantly higher cortical rCBF than the men (p < 0.05). In the stroke patients, the whole-brain CBF values showed high reproducibility, with high correlations between those obtained at the first and second studies (y = -3.5 + 1.03x; r = 0.90; p < 0.001). In the subarachnoid hemorrhage patients, the vasospastic area showed significantly lower rCBF than the normal cortical rCBF (p < 0.01) and the nonvasospastic area (p < 0.01). Brain regions with rCBF levels below 20 ml/100 g/min showed infarction on the follow-up CT scan.

CONCLUSION

The IMP-ARG method is reproducible, sensitive to hypoperfusion and feasible for the quantitative evaluation of rCBF in routine clinical practice.

Distribution of heat shock proteins in eutopic and ectopic endometrium in endometriosis and adenomyosis

OBJECTIVE

To evaluate the pathophysiologic role of heat shock proteins and to examine the effect of danazol on these proteins in patients with endometriosis and adenomyosis.

DESIGN

Immunohistochemical identification of human heat shock proteins 27, 60, and 70 in endometrial glandular cells identified using monoclonal antibodies.

SETTING

Department of obstetrics and gynecology in a university hospital.

PATIENT(S)

Subjects were 119 women with documented endometriosis or adenomyosis. The subjects were divided into three groups: fertile control (n = 38), with 14 in the proliferative phase and 24 in the secretory phase; endometriosis (n = 38); and adenomyosis (n = 43), including 33 who underwent hysterectomy and 10 treated with danazol.

MAIN OUTCOME MEASURE(S)

Staining of glandular cells by semiquantitative immunostaining (evaluation nomogram) score.

RESULT(S)

Significantly increased expression of heat shock protein 27 was noted in eutopic endometrium from patients with endometriosis and adenomyosis as compared with controls, regardless of the menstrual phase. The scores for heat shock protein 27 and heat shock protein 70 in the ectopic endometrium of patients with endometriosis were low compared with those in eutopic endometrium, whereas in adenomyosis, the scores were similar to those of eutopic endometrium. After treatment with danazol, the expression of heat shock proteins returned to control levels.

CONCLUSION(S)

We suggest that abnormally increased expression of heat shock proteins plays a role in the pathophysiology of endometriosis and adenomyosis.

MRI of acute cerebral infarction: a comparison of FLAIR and T2-weighted fast spin-echo imaging

Fluid-attenuated inversion-recovery (FLAIR) sequences have been reported to provide high sensitivity to a wide range of central nervous system diseases. To our knowledge, however, FLAIR sequences have not been used to study patients with acute cerebral infarcts. We evaluated the usefulness of FLAIR sequences in this context. FLAIR sequences were acquired on a 0.5 T superconducting unit within 8 h of the onset in 19 patients (aged 26-80 years) with a total of 23 ischaemic lesions. The images were reviewed retrospectively by three neuroradiologists, and the FLAIR images were compared with T2-weighted fast spin-echo images. All but one of the ischaemic lesions involving grey matter was clearly demonstrated on FLAIR images as increased signal intensity in cortical or central grey matter. FLAIR images were particularly useful for detecting the hyperacute cortical infarcts within 3 h of onset, which were not readily detected on the spin-echo images. In 9 of 11 patients with complete proximal occlusion, the distal portion of the cerebral artery was visible as an area of high signal intensity on FLAIR images.

Technetium-99m-ECD brain SPECT in misery perfusion

Discordant findings of 99mTc-methyl cysteinate dimer (99mTc-ECD) brain distribution have been reported when brain tissue is supplied by excess blood flow. We evaluated changes in 99mTc-ECD brain activity in the opposing pathological state, in which cerebral blood flow (CBF) is more profoundly impaired than metabolism, and analyzed the relationship of 99mTc-ECD activity with CBF and metabolism to investigate the dominant regulating factor on 99mTc-ECD distribution.

METHODS

Twelve patients with unilateral intracranial steno-occlusive diseases were evaluated using dynamic and static 99mTc-ECD SPECT. Relative 99mTc-ECD activities and the retention ratio of the affected and unaffected cortices were compared with CBF and oxygen metabolism obtained by PET. Change in the relationships until 1 hr after tracer injection were also analyzed.

RESULTS

Relative 99mTc-ECD activity was significantly correlated with CBF, and the highest correlation was obtained for the first minute of imaging (r = 0.674, p < 0.0010. Fifteen minutes after injection, the correlation coefficient with CBF decreased, whereas higher correlation was observed with the parameter of oxygen metabolism (r = 0.758-0.815, p < 0.001). Changes in the retention ratio were dependent on changes in oxygen metabolism, and the retention ratio for the high oxygen extraction fraction (OEF) area was the same as that for the normal OEF area.

CONCLUSION

In addition to CBF, brain distribution on 99mTc-ECD SPECT images is affected by brain metabolism, especially on delayed images after injection. The degree of discrepancy between CBF and metabolism should be considered when interpreting images of the misery perfusion state.

Subacute and chronic subarachnoid hemorrhage: diagnosis with fluid-attenuated inversion-recovery MR imaging

PURPOSE

To evaluate fluid-attenuated inversion-recovery (FLAIR) magnetic resonance (MR) imaging in the detection of subacute and chronic subarachnoid hemorrhage.

MATERIALS AND METHODS

The authors performed 19 FLAIR MR imaging examinations at 0.5 T in 14 adult patients with subarachnoid hemorrhage 3-45 days after the ictus and 22 FLAIR examinations in 22 adult control subjects. The detection of subacute and chronic subarachnoid hemorrhage on FLAIR images was compared with the detection on conventional spin-echo MR and computed tomographic (CT) images.

RESULTS

In the detection of subacute subarachnoid hemorrhage, FLAIR (100% detection) was significantly superior to T1-weighted imaging (36% detection, P < .01), T2-weighted imaging (0% detection, P < .02), and CT (45% detection, P < .02 [Fisher exact test]). Although FLAIR imaging (63% detection) was superior in chronic subarachnoid hemorrhage detection, there were no statistically significant differences between modalities. FLAIR imaging demonstrated all subarachnoid hemorrhage areas as high-signal-intensity areas within 18 days and up to a maximum of 45 days after the ictus. In a blind comparison, no FLAIR images acquired in control subjects were confused with those acquired in patients.

CONCLUSION

FLAIR diagnostic images are superior to conventional MR or CT images in patients with subacute subarachnoid hemorrhage.

Subependymoma of the septum pellucidum: characterization by PET

We report the evaluation of a subependymoma of the septum pellucidum by positron emission tomography (PET) with analysis of 18F-fluorodeoxyglucose (FDG) kinetics. The tumor showed exceedingly low rates of glucose metabolism (rCMRG1) and kinetic constants (K1, K2, and K3). This hypometabolism indicates low cellular density and slow growth.

Early delineation of cerebral glioma using amino acid positron tracers

A 56-yr-old housewife with cerebral astrocytoma was reported with positron emission tomography findigns using 11C-methyl-L-methionine (11C-Met) and 18F-fluorophenylalanine (18F-Phe) tracers. 11C-Met and 18F-Phe accumulated intensely in tumor lesions, although CT scans showed only a foggy low-density area. Five years and one month after, an enhancing mass appeared on CT scans. Thus, amino acid tracers may play a important role in the early diagnosis of gliomas.

Indications for differential diagnosis of nontumor central nervous system diseases from tumors. A positron emission tomography study

To accurately differentiate nontumor central nervous system (CNS) diseases from brain tumors, we retrospectively evaluated the cerebral circulation and metabolism in patients with nontumor CNS diseases using positron emission tomography (PET). Regional cerebral blood flow (rCBF), cerebral blood volume (rCBV), oxygen extraction fraction (rOEF), the metabolic rates of oxygen (rCMRO2), and of glucose (rCMRGI), and the uptake of 11C-methyl-L-methionine (11C-Met) were visually evaluated in lesions and compared with values for the contralateral white matter regions. PET findings were correlated with those of x-ray computed tomography (CT) and magnetic resonance imaging (MRI), and were analyzed for nontumor CNS diseases and cerebral gliomas. rCBF and rCBV were changeable from disease to disease or from stage to stage of disease progression. rOEF and rCMRO2 remained low in 5 and 6, respectively, of 9 nontumor CNS diseases examined, whereas these parameters were increased in CNS infections such as brain abscess. Overall, noteworthy was the locally increased rOEF and rCMRO2 in the patients with a brain abscess in contrast to the values for patients with gliomas. rCMRGI reflected biological characteristics of each disease, and correlated with cell density, whether reactive glial cells or inflammatory cells. 11C-Met was accumulated at a certain stage of nontumor CNS diseases, which implied uptake of the tracer as a result of disruption of the blood-brain barrier as well as metabolic incorporation.

Quantitative evaluation of neutral amino acid transport in cerebral gliomas using positron emission tomography and fluorine-18 fluorophenylalanine

To elucidate the mechanism of large neutral amino acid (LNAA) transport in cerebral gliomas and to evaluate the clinical usefulness of positron emission tomography (PET) with fluorine-18 fluorophenylalanine (18F-Phe), we examined 18 patients with cerebral glioma using dynamic PET and 18F-Phe. By employing two-compartment model analysis, the influx rate K1, the efflux rate k2 and the distribution volume (Vd) of 18F-Phe were estimated in tumour tissue and contralateral normal grey matter. 18F-Phe showed increased accumulation in tumour tissue regardless of the grade of malignancy in all patients. The rate of uptake of 18F-Phe in high-grade glioma was significantly higher than in low-grade glioma (P <0.05). However, it was difficult to evaluate the tumour grade only from the 18F-Phe accumulation in individual cases. Values of K1 and Vd were significantly increased in the tumour tissue. The K1 value of the tumour tissue tended to decrease with increasing LNAA concentration in plasma. Therefore, influx of 18F-Phe into tumour tissue is mainly related to the carrier-mediated active transport. It is concluded that PET with 18F-Phe is of clinical value for tumour detection rather than assessment of tumour malignancy.

Long-term positron emission tomography evaluation of slowly progressive gliomas

Non-invasive positron emission tomography (PET) was performed to identify changes in blood flow and metabolism, specific to early stages of tumour occurrence or recurrence. 2 patients with slowly progressive gliomas from early to late stages of tumour development were analysed by serial PET measurements of circulation and metabolism using 15O-gas and 18F-fluorodeoxyglucose. PET revealed a persistent depression of oxygen metabolism, as indicated by the regional oxygen extraction fraction or metabolic rate of oxygen, in the regions where tumours were later found. Abnormal blood flow and metabolism may precede the morphological changes detected by computed tomography (CT) in patients with gliomas.

Radiation-induced meningioma evaluated with positron emission tomography with fludeoxyglucose F 18

We describe a patient with radiation-induced meningioma 12 years after cranial irradiation for ectopic germinoma. PET scans with fludeoxyglucose F 18 showed a high glucose metabolic rate in the meningioma despite a benign histologic appearance.