Brain activation during ideomotor praxis: imitation and movements executed by verbal command

BACKGROUND

Ideomotor apraxia is a disorder of both imitation movements and movements executed by verbal command. Lesion studies have identified the left parietal lobe as the neural correlate for ideomotor praxis (IP), although there are opposing views.

OBJECTIVES

To localise the neural substrates for IP using functional magnetic resonance imaging. Brain regions activated by both imitation and verbal command movements were tested against a simple self paced movement.

METHODS

Twenty two young, right handed, healthy subjects were examined. Functional and anatomical data were acquired. The experiment comprised three motor conditions (imitation, movements executed by verbal command, and finger bending/unbending) and a rest condition. All motor tasks were performed using the left hand. Eighteen drawings of left hand postures were presented for the imitation condition. Identical postures were instructed verbally for the verbal command condition. The finger bending/unbending movement was self paced. Blood oxygenation level dependent (BOLD) signal increases were compared during two kinds of IP (imitation and verbal command movements) and during finger bending/unbending movements.

RESULTS

The depth of the posterior part of the left intraparietal sulcus and bilateral precunei were activated during both imitation and verbal command movements. The difference in BOLD signal between imitation and verbal command movements was localised in the dorsal and ventral occipital areas. BOLD signal differences for movements executed by verbal command against imitation were observed in the superior temporal areas.

CONCLUSIONS

The depth of the posterior part of the left intraparietal sulcus and bilateral precunei are the neural substrates for IP.

[A case of ischemic dilated cardiomyopathy, mitral regurgitation and congestive heart failure successfully treated by Batista operation, coronary artery bypass grafting and mitral valve replacement; usefulness of myocardial scintigraphy]

A 75-year-old man diagnosed as having ischemic dilated cardiomyopathy, congestive heart failure and mitral regurgitation underwent left ventricle volume reduction operation (Batista), coronary bypass grafting and mitral valve replacement because myocardial infarction had developed at lateral, inferior and small area of apex wall, not at interventricular septum. Left ventricular endodiastolic volume index and left ventricular endosystolic volume index decreased from pre-operative values of 155, and 128 ml/m2 to post-operative values of 113, and 82 ml/m2, respectively. Left ventricular ejection fraction increased from a pre-operative value of 17% to a post-operative value of 27%. This evaluation was performed by myocardial scintigraphy (quantitative gated spect: QGS). This method was bloodless and useful for determination of indication of left ventricle volume reduction surgery including Batista operation and pre- and post-operative evaluation of this type of surgery. Today, Batista operation is, generally speaking, performed for non-ischemic dilated cardiomyopathy. In this case, however, Batista operation was applied to ischemic dilated cardiomyopathy and was very effective.

Activation of supplementary motor area during imaginary movement of phantom toes

To evaluate changes in the human cerebral cortex after lower limb amputation, we studied repetitive toe movements using functional magnetic resonance imaging. The subject did not experience any phantom pain but had a vivid sensation of the phantom limb's presence and was able to imagine the movement of her phantom toes and ankle. Actual movement of her normal limb activated the contralateral supplementary motor area (SMA), the primary motor cortex (M1), and the primary somatosensory cortex (S1). Movement of her phantom limb activated the contralateral SMA and the M1. Imaginary movement of her normal toes without actual movement activated the contralateral SMA. The slice level that was activated by the movement of the phantom limb was shifted 8 mm caudally, suggesting that cortical reorganization had occurred after the lower limb amputation.

Abnormality of the myocardial sympathetic nervous system in a patient with Becker muscular dystrophy detected with iodine-123 metaiodobenzylguanidine scintigraphy

PURPOSE

This study was performed to determine whether I-123 metaiodobenzylguanidine (MIBG) scintigraphy can depict myocardial sympathetic nerve abnormalities in Becker muscular dystrophy.

MATERIALS AND METHODS

A 34-year-old man with Becker muscular dystrophy underwent Tl-201 and I-123 MIBG scintigraphy sequentially before and 4 months after the beginning of oral administration of enalapril maleate, an angiotensin-converting enzyme inhibitor.

RESULTS

Before and during treatment, stress Tl-201 scintigraphy revealed nonreversible myocardial perfusion defects in the anterior, inferoposterior, and apical walls, and I-123 MIBG scintigraphy depicted a region with decreased sympathetic nerve function or innervation. Before treatment, the I-123 MIBG heart count- mediastinum count (H:M) ratio was 2.1 and the washout rate was 21% on delayed images obtained 4 hours after the injection of I-123 MIBG, indicating hyperactivity of the sympathetic nervous system in the myocardium. During treatment, the H:M ratio was 3.0 and the washout rate was 15%.

CONCLUSION

With I-123 MIBG scintigraphy it is possible to evaluate an abnormality of the myocardial sympathetic nervous system and the efficacy of administration of an angiotensin-converting enzyme inhibitor in this disease.

Proton magnetic resonance spectroscopy in disturbances of cortical development

Proton magnetic resonance spectroscopy(1H-MRS) can be used for looking at cerebral metabolites in vivo. However, measurement of concentrations of cerebral metabolites in patients with disturbances of cerebral development have not been successful. Our purpose was to measure the concentrations of cerebral metabolites in such patients. We carried out quantitative 1H-MRS in eight patients with cortical dysplasia, four with lissencephaly and three with heterotopic grey matter and six age-matched normal controls. Regions of interest for 1H-MRS were set over the affected cortex in the patients and the occipital cortex in controls. The calculated concentration of N-acetylaspartate ([NAA]) was significantly lower in the affected cortex in patients with cortical dysplasia (P < 0.05), lissencephaly (P < 0.01), and heterotopia (P < 0.05) than in controls, idnicating a decreased number and/or immaturity or dysfunction of neurones in the affected cortex. The concentration of choline ([Cho]) was significantly lower in patients with lissencephaly (P < 0.01) than in controls, indicating glial proliferation and/or membrane abnormality.

Proton magnetic resonance spectroscopy of Sjögren-Larsson syndrome heterozygotes

A deficit of fatty alcohol:NAD+ oxidoreductase complex (FAO) activity has been detected in patients with the Sjögren-Larsson syndrome (SLS). A moderate decrease in FAO activity has also been reported in heterozygote SLS subjects. Abnormal peaks were detected with proton magnetic resonance spectroscopy (1H-MRS) in homozygote SLS subjects. The purpose of this study was to examine whether 1H-MRS can be used to detect metabolic and/or pathological abnormalities in heterozygote SLS subjects. Four SLS heterozygotes were examined using 1H-MRS. A moderate decrease in FAO activity was demonstrated in two of the four heterozygotes. Abnormal peaks were detected at 0.9 ppm in the spectrum from cerebral hemispheres of every heterozygote. 1H-MRS was able to detect an abnormal accumulation of fatty alcohols and lipids, which is expected to increase due to an decrease in FAO activity or dysmyelination in heterozygote SLS subjects. Thus, 1H-MRS is suggested to be a powerful tool in the screening of SLS heterozygotes.

Validation of CBF measurement with non-invasive microsphere method (NIMS) compared with autoradiography method (ARG)

The purpose of this study is to examine the correlation of measured regional cerebral blood flow (rCBF) by means of a new microsphere method (non-invasive microsphere method), to the autoradiography (ARG) method, which is an established quantification method for 123I-IMP brain SPECT. The non-invasive microsphere (NIMS) method and ARG method were simultaneously applied to 30 patients, and quantified rCBF maps were calculated with each method. A significant correlation (r = 0.70: p < 0.001) was detected between mCBF values calculated with the NIMS and ARG methods. This new method seems to reliably quantify rCBF with brain SPECT.

[A case of orbital MALT lymphoma in which 67Ga scintigraphy was useful for evaluating the radiation therapy response]

A 67-year-old man was hospitalized at our institution complaining with epiphora and exophthalmos on the left side. Magnetic resonance imaging (MRI) showed an ill demarcated retrobulbar mass in the left orbit. 67Ga scintigraphy revealed avid uptake in the left orbital region. The patient was treated with radiation therapy. One month after the radiation therapy, the size of the mass decreased remarkably on MRI. 67Ga planar imaging after treatment showed no uptake, but 67Ga SPECT showed slightly increased uptake in the left orbital region. One year after the radiation therapy, MRI showed residual mass in the left orbital region. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. 1.8 years after the radiation therapy, MRI showed the residual mass with no interval change in size. Both 67Ga planar imaging and SPECT showed no uptake in the left orbital region. The patient remains well with no evidence of local recurrence. 67Ga scintigraphy is useful in assessing the response to radiation therapy of MALT lymphoma in this case.

Multiple myeloma showing increased accumulation of Tc-99m hexamethylpropylene amine oxime on brain SPECT

The authors report a case of multiple myeloma with increased accumulation of Tc-99m hexamethylpropylene amine oxime (HMPAO) on brain SPECT. Tc-99m HMPAO is a lipophilic compound that freely passes through the intact blood-brain barrier and cell membrane and is rapidly converted to a hydrophilic form by glutathione and then retained in the neuron for several hours. In general, Tc-99m HMPAO shows decreased accumulation in brain tumors. However, some reports of increased accumulation in brain tumors, such as meningioma, glioblastoma multiforme, high-grade astrocytoma, pituitary adenoma, and multiple myeloma, have been published. The Tc-99m HMPAO uptake in these tumors has been attributed to tumor blood flow or glutathione contents within the tumor. With regard to uptake to Tc-99m HMPAO in multiple myeloma, the tumor size is considered to be an additional factor.

Hydraulic analysis of the functional properties of saline-jet aspiration thrombectomy catheters

The purpose of this paper is to clarify the functional properties of a saline-jet aspiration thrombectomy catheter based on hydraulics. This catheter, developed by the authors, aspirates intravascular thrombi by means of the effect of a high-speed jet. We have derived the relationships between Qs, Qa, and p(n), where Qs is the water supply rate, Qa is the water aspiration rate and p(n) is the negative pressure created in the distal lumen of the catheter. The relationships are represented by simple equations using c1 and c2, where c1 and c2 are coefficients proper to the catheter. We have obtained c1 and c2 experimentally for three types of catheter with different distal shapes. Two practical conclusions are derived from this study. First, making a short taper at the distal end increases the negative pressure created and is advantageous for thrombus aspiration. Second, making the diameter of the inner tube and nozzle smaller is essential for improving the aspiration ability of the catheter.

Hemodynamic changes around cerebral arteriovenous malformation before and after embolization measured with PET

To estimate the changes in regional cerebral blood flow (rCBF) around cerebral arteriovenous malformation (AVM) before and after embolization, 6 patients with AVM were sequentially examined with positron emission tomography (PET). PET depicted the remodeling of rCBF in the ipsilateral hemisphere of AVM after embolization. Decrease of rCBF in the ipsilateral hemisphere was also detected in patients with focal symptoms before embolization, and improvement of clinical symptoms after embolization corresponded to disappearance of rCBF decrease. PET can detect hemodynamic changes after embolization, and has a possibility to estimate the effect of embolization in patients with AVM.

Proton MR spectroscopy of Sjögren-Larsson's syndrome

We performed single-voxel proton MR spectroscopy (1H-MRS) in two children with Sjögren-Larsson's syndrome (SLS). Both patients showed two abnormal spectral peaks at 1.3 ppm and 0.9 ppm that were obtained with short echo times. These two abnormal spectral peaks were seen in high-intensity areas on T2-weighted images and also in basal ganglia of normal intensities. 1H-MRS may be useful for establishing the diagnosis and investigating the natural history of SLS, and for evaluating the efficacy of therapeutic approaches to SLS.

Functional magnetic resonance imaging localization of tactile reading phonograms in Japanese subjects

Functional magnetic resonance imaging (fMRI) is used to investigate the neural basis for tactile reading of Japanese phonograms (kana) with the left hands of six normal right-handed Japanese subjects. Both the tactile reading and recognition tasks activated the areas surrounding the left and right central sulci in all subjects. The region surrounding the left intraparietal sulcus was activated during the tactile reading task in all subjects, whereas the region was activated during the tactile recognition task in only two subjects. These results suggest the bilateral central sulcus areas participate in the manipulatory movement of the left hand and processing of the somatosensory information, and the left intraparietal sulcus area participates inevitably, in the tactile reading of Japanese phonograms. Our experiments support the essential role of the intraparietal sulcus area in the phonogram-reading process.

3 beta-p-hydroxybenzoyldehydrotumulosic acid from Poria cocos, and its anti-inflammatory effect

The structure of a new triterpene derivative isolated from Poria cocos was determined to be 3 beta-p-hydroxybenzoyldehydrotumulosic acid by spectral and chemical methods. 3 beta-p-hydroxybenzoyldehydrotumulosic acid showed marked inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)- and arachidonic acid (AA)-induced ear inflammation in mice. The 50% inhibitory doses of 3 beta-p-hydroxybenzoyldehydrotumulosic acid were 0.27 and 1.25 mg per ear on TPA- and AA-induced inflammation, respectively.

[1H-NMR spectroscopy of a patient with pachygyria]

1H-NMR spectroscopy was performed on a 6-month-old boy with pachygyria. A MRI study demonstrated an abnormally thick cortex localized in the right occipital lobe. 1H-NMR spectrums were collected from the lesion and the contralateral cortex that appeared normal on MRI. The N-acetylaspartate (NAA)/Cre (creatine) ratio was markedly lower in the abnormal cortex than in the contralateral cortex and the occipital cortex. NAA localizes to neurons, axons, dendrites and synaptic connections and increases with maturation of neurons. Its decrease is considered to represent the decrease in the number of these structures and/or disturbance of neuronal maturation. We conclude that NAA/Cre can be an important index that reflects the pathogenesis of pachygyria.

Myocardial fatty acid metabolism in diabetic mice with 125I-BMIPP

In patients with diabetes mellitus, the existence of diabetic cardiomyopathy was substantiated. This study was undertaken to evaluate the myocardiac fatty acid metabolism of diabetic mice (n = 21) and controls (n = 21) in 125I-BMIPP in fasted and unfasted states. 125I-BMIPP of 370 kBq was given and thirty minutes later, animals from both groups were killed. Samples of hearts, liver and other organs were removed, weighed and then counted in a scintillation counter. The percent injected dose/g of hearts of diabetic mice was significantly reduced compared to controls in unfasted (p < 0.05) and fasted (p < 0.01) groups. These findings may reflect impaired fatty acid utilization of the hearts in diabetic mice compared to controls.

[The change of hepatic energy status after transcatheter arterial embolization (TAE) for hepatocellular carcinoma--a study using 31P-MRS]

In six patients with hepatocellular carcinoma, adenosine triphosphate (ATP) phosphomonoester (PME), phosphoric acid (Pi) and pH were measured before and after transcatheter arterial embolization (TAE), using 31P-magnetic resonance spectroscopy (MRS). The effectiveness of TAE was judged by the extent of lipiodol accumulation within the tumor and change in serum alphafetoprotein level. The pH within the tumor decreased 2-9 days after TAE in all the cases, and beta ATP/Pi ratio decreased when TAE was effective, whereas the ratio did not decrease when TAE was ineffective. The beta ATP/Pi ratio measured by 31P-MRS seems to be a useful, non-invasive marker of the anti-tumor effect of TAE, although further investigation is needed.

[Evaluation of neuro-Behçet disease with 99mTc-HMPAO brain SPECT: comparison with MR imaging]

The purpose of this study was to evaluate the brain perfusion of neuro-Behçet disease using 99mTc-HMPAO. In total, nine patients (7 men and 2 women) were evaluated. Seven were in the chronic phase, one was acute and the other was subacute. The results of perfusion study were compared with the MRI findings. The findings of chronic-phase neuro-Behçet disease were as follows: 99mTc-HMPAO showed hypoperfusion of the cerebellum in 3, brain stem in 5, and cerebral cortex in 4 patients. Moreover, asymmetry of the basal ganglia and thalamus was seen in 4 cases with 99mTc-HMPAO. MRI showed atrophy of the cerebellum in 4, brain stem in 5 and cerebral cortex in 2 patients. One acute patient showed a perfusion defect with 99mTc-HMPAO that was consistent with the vasculitis shown with MRI. In the remaining subacute patient, perfusion defect was demonstrated with 99mTc-HMPAO, consistent with the infarction shown with MRI. It is concluded that brain perfusion scintigraphy is useful to evaluate the brain blood flow of neuro-Behçet disease.

[Evaluation of 99mTc-ECD SPECT for the detection of brain tumor: comparison with 201TI SPECT]

For the evaluation of brain tumor (n = 15), we performed both dynamic and static 99mTc-ECD (ECD) SPECT studies 201Tl SPECT was also used for comparison with the results of ECD SPECT. Dynamic ECD SPECT was obtained following the injection of 600 MBq of ECD. Five min after the injection of ECD, static ECD SPECT was performed. 201Tl SPECT was obtained 10 min after the injection of 74MBq. Abnormal uptake was recognized in 7 of 15 tumors with dynamic ECD: 5 of 7 meningiomas, 1 of 1 glioblastoma and 1 of 1 astrocytoma. However, no abnormal uptake was seen in 3 of 3 benign tumors (1 low grade astrocytoma, 1 hemangioma, 1 cranio-pharyngioma) and in 2 of 2 brain metastases. In contrast abnormal uptake was seen in 11 of 15 tumors with 201Tl:7 of 7 meningiomas; 2 of 2 brain metastases, 1 of 1 glioblastoma and 1 of 1 craniopharyngioma. No abnormal uptake was seen in 3 of 3 benign tumors (1 hemangioma and 2 low grade astrocytomas). Equivocal uptake was seen in 1 low grade astrocytoma with dynamic ECD and 201Tl. The mechanism of the accumulation of dynamic ECD to brain tumor is unclear. However, it may reflect not only blood flow, but also metabolism.

Inhibitory effects of lanostane-type triterpene acids, the components of Poria cocos, on tumor promotion by 12-O-tetradecanoylphorbol-13-acetate in two-stage carcinogenesis in mouse skin

Pachymic acid, 3-O-acetyl-16 alpha-hydroxytrametenolic acid, and poricoic acid B had been isolated from the sclerotium of Poria cocos Wolf. These compounds showed a strong inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate-induced inflammation in mice. At 0.2 mumol/mouse, these compounds markedly inhibited the promoting effect of 12-O-tetradecanoylphorbol-13-acetate (1 microgram/mouse) on skin tumor formation following initiation with 7,12-dimethylbenz[a]anthracene (50 micrograms/mouse).

Inhibitory effect of taraxastane-type triterpenes on tumor promotion by 12-O-tetradecanoylphorbol-13-acetate in two-stage carcinogenesis in mouse skin

Two taraxastane-type hydroxy triterpenes, taraxasterol and faradiol, isolated from the flowers of Compositae plants Cynara scolymus (artichoke) and Chrysanthemum morifilolium (chrysanthemum), respectively, showed strong inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in mice. At 2.0 mumol/mouse, these compounds inhibited markedly the tumor-promoting effect of TPA (1 microgram/mouse) on skin tumor formation following initiation with 7,12-dimethylbenz[alpha]anthracene (50 micrograms/mouse).

Inhibitory effects of sterols isolated from Chlorella vulgaris on 12-0-tetradecanoylphorbol-13-acetate-induced inflammation and tumor promotion in mouse skin

Inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation in mice was observed in the methanol extract of Chlorella vulgaris, a green alga. The hexane soluble fraction obtained from the methanol extract exhibited marked inhibitory activity from which were isolated two delta(5,7)-sterols (ergosterol and 7-dehydroporiferasterol), two delta(5,7,9(11))-sterols [7,9(11)-dehydroergosterol and 7,9(11)-bisdehydroporiferasterol], two 5 alpha, 8 alpha-epidioxy-delta(6)-sterols (ergosterol peroxide and 7-dehydroporiferasterol peroxide), and a 7-oxo-delta(5)-sterol (7-oxocholesterol), among others. The delta 5'7-sterols, 5 alpha, 8 alpha-epidioxy-delta(6)-sterols and 7-oxo-delta 5-sterol inhibited TPA-induced inflammation in mice. The 50% inhibitory dose of these compounds for TPA-induced inflammation was 0.2-0.7 mg/ear. Furthermore, ergosterol peroxide markedly inhibited the tumor-promoting effect of TPA in 7,12-dimethylbenz[a]anthracene-initiated mice.

Inhibitory effect of alkane-6,8-diols, the components of safflower, on tumor promotion by 12-O-tetradecanoylphorbol-13-acetate in two-stage carcinogenesis in mouse skin

Erythro-alkane-6,8-diols were isolated from the flowers of Carthamus tinctorius. 12-0-Tetradecanoylphorbol-13-acetate (TPA, 1 microgram/ear), a tumor-promoting agent, was applied to the ears of mice to induce inflammation. Of 8 alkane-6,8-diols assayed, the C27, C31, C32, C33 and C35 alkane diols inhibited the inflammation. The 50% inhibitory dose of these compounds for TPA-induced inflammation was 0.5-0.7 mg/ear. However, C21, C23 and C25 alkane-6,8-diols were found to have no effect. Furthermore, the mixture of erythro-alkane-6,8-diols from the flowers of C. tinctorius markedly suppressed the promoting effect of TPA on skin tumor formation in mice following initiation with 7,12-dimethylbenz[a]anthracene.

Sequential MR signal change of the thrombus in the false lumen of thrombosed aortic dissection

The evolution of thrombus in the false lumen was investigated in 14 patients with thrombosed aortic dissection, by reviewing the findings acquired at a total of 21 magnetic resonance imaging (MRI) examinations performed between 2 and 146 days after the onset. On electrocardiographic gated 1.5-Tesla MRI, T1-(TR/TE = 860 +/- 190 ms/17-40 ms) and T2-(TR/TE = 1620 +/- 240 ms/70-80 ms) weighted spin echo and gradient echo images were obtained, and the signal intensity of the thrombus on these images was evaluated independently by two observers. The density of the thrombus was also evaluated using computed tomography (CT) images obtained at a total of 54 examinations. On both T1- and T2-weighted images, the thrombus showed signal iso- or hypointensity compared to that of skeletal muscle during the first several days after the onset and, thereafter, showed signal intensity similar to that of fat tissue. It is suggested that the low signal intensity of the thrombus observed during the initial period after the onset was caused by the presence of deoxyhemoglobin and the high intensity observed thereafter was caused by methemoglobin. Focal discrepancy of the signal intensities within two parts of the lumen on spin echo images was observed in 7 patients, and a low-intensity layer on the surface of the thrombus inside the false lumen was observed on gradient echo images in 5 of these 7 patients. This characteristic MR signal change of the thrombus in the false lumen of thrombosed aortic dissection provides useful information concerning the age of the thrombus and in the differential diagnosis of the thrombus from a mural thrombus of aortic aneurysm.

Clinical application of spontaneous red blood cell labeling with Tc-99m sodium pertechnetate

Red blood cells (RBC) may be labeled with Tc-99m after Tc-99m sodium pertechnetate is injected in the presence of a reducing agent, such as stannous chloride. Thus, spontaneous RBC labeling with Tc-99m is expected to be seen in patients with a high plasma concentration of tin. Spontaneous RBC labeling with Tc-99m was obtained in a 73-year-old woman who was clinically diagnosed with tin intoxication and proved to have a high concentration of plasma tin. The RBC labeling rate was calculated as 96% with blood sampling. Spontaneous RBC labeling with Tc-99m is a very simple method for proving a high plasma tin concentration and is adaptable to clinical diagnosis.

[Standardization of regional cerebral count corrected by equilibrium blood count with 99mTc-HMPAO brain SPECT]

To standardize the regional cerebral count with 99mTc-HMPAO, equilibrium blood count of which trapping mechanism is the same as the brain was used in seven patients with cerebrovascular disease. We injected 99mTc-HMPAO 740 MBq in 10-15 sec and got sequential arterial sampling in patients who were undertaken with PET. Four hours later 99mTc-HMPAO brain SPECT was taken and a venous sampling was drawn for determining the equilibrium blood count. Correlation between the area of arterial time activity curve and equilibrium venous blood count was 0.93. After 44 regions (36 in cortical area, 8 in deep area) with 99mTc-HMPAO brain SPECT were placed, SPECT counts were corrected by standardization of equilibrium venous blood count. The correlation between rCBF determined from C15O2 PET and corrected SPECT counts was 0.80 and 0.67, cortical area and deep area, respectively. We concluded that 99mTc-HMPAO brain SPECT count can be corrected by equilibrium blood count to standardize the regional cerebral counts.

Myocardial damage in patients with dilated cardiomyopathy: CT evaluation

OBJECTIVE

The purpose of this study was to evaluate myocardial damage in patients with dilated cardiomyopathy (DCM) by ultrafast CT (UFCT) and estimate the improvement of DCM.

MATERIALS AND METHODS

Seventeen patients with DCM were examined with UFCT, cardiac catheterization, left ventriculography (LVG) with manometry, and thallium myocardial scintigraphy (SCINTI). The findings of each examination were compared with each other. Especially, UFCT findings were compared with LV function.

RESULTS

Late enhancement, focal wall thinning, and fatty component were detected by UFCT as focal abnormal findings. Left ventricular segments with these findings on UFCT correlated well with asynergy on LVG (p < 0.01) and perfusion defects on SCINTI (p < 0.05). Patients with these findings on UFCT showed significantly lower LV ejection fractions (p < 0.05), higher LV end-diastolic pressure (p < 0.05), and a higher incidence of ventricular tachycardia (p < 0.05).

CONCLUSION

The focal myocardial abnormalities in DCM patients were well depicted with UFCT. Ultrafast CT was useful in estimating the severity of DCM and classifying the DCM patients.

Quantitative evaluation of mitral regurgitation with ultrafast CT

OBJECTIVE

To quantify cardiac valvular regurgitation, ultrafast CT was performed in 44 patients (including 27 patients with mitral regurgitation).

MATERIALS AND METHODS

Stroke volume of the left ventricle was calculated by modified Simpson's rule with cine mode scanning of ultrafast CT, and ventricular output was measured as the product of stroke volume and heart rate. Cardiac output was calculated in the ascending aorta by the formula of the indicator dilution method with flow mode scanning of ultrafast CT. The difference between the left ventricular output and cardiac output was defined as "mitral regurgitant volume." Left ventriculography was also performed at the same time, to estimate the degree of mitral regurgitation according to Sellers' classification.

RESULTS

There was significant correlation between regurgitant fraction, standardized regurgitant volume, and grade of mitral regurgitation estimated by left ventriculography.

CONCLUSION

CT can measure mitral regurgitant volume by the combination of volumetry and indicator dilution method.

Detection of postural cerebral hypoperfusion with technetium-99m-HMPAO brain SPECT in patients with cerebrovascular disease

Seventeen of 19 patients (67 +/- 8 yr, 17 males and 2 females) had more than 75% unilateral stenosis or occlusion of the internal carotid or middle cerebral artery and two patients had carotid endarterectomy that previously had 90% stenosis of the internal carotid artery. They were studied during upright 99mTc-HMPAO brain SPECT. HMPA was injected immediately after arising from a supine position. Patients were classified into Group A (n = 10) with occlusion of the internal carotid or the middle cerebral artery or Group B (n = 9) with more than 75% unilateral stenosis of the internal carotid or the middle cerebral artery and with carotid endarterectomy. Additional cerebral blood flow perfusion abnormalities between upright and supine 99mTc-HMPAO brain SPECT were detected in seven patients in Group A and in only one patient in Group B. Semiquantitative analysis showed that the asymmetric ratios between upright and supine positions changed significantly in Group A from 0.82 +/- 0.15 to 0.89 +/- 0.10 (p < 0.01), but not in Group B, from 0.89 +/- 0.11 to 0.92 +/- 0.12 (ns). Additional perfusion abnormalities were relevant to occlusion of the internal carotid or middle cerebral artery indicated postural cerebral hypoperfusion. We conclude that upright 99mTc-HMPAO brain SPECT visualizes postural cerebral hypoperfusion possibly related to silent cerebral ischemia.

[Detection of myocardial damage in patients with dilated cardiomyopathy using ultrafast CT]

The myocardial characteristics of DCM patients were investigated by ultrafast CT (UFCT), left ventriculography (LVG) and T1 myocardial scintigraphy (SCINTI). Late enhancement, focal wall thinning and intramyocardial fatty components were detected as focal abnormal findings by UFCT. The regions of asynergy detected by LVG and perfusion defect detected by SCINTI were well correlated with those of focal abnormal findings detected by UFCT. There were significant differences between patients with and without focal abnormal findings, in ejection fraction and end-diastolic pressure of left ventricle and the incidence of ventricular arrhythmia. It is possible that these focal abnormal findings represented focal ischemic myocardial damage in DCM patients. DCM patients were divided into two different functional groups by UFCT findings.

[Detection of myocardial fatty components with ultrafast CT]

Intramyocardial fatty components are sometimes depicted by CT of the thorax. However, no studies have investigated the distribution, frequency and cause of these components by using statistical analysis. Three hundred forty-five patients with various cardiac diseases were examined with an ultrafast CT scanner, and intramyocardial fatty components were detected in 15 (4.3%) of them. The frequency of intramyocardial fatty components in each disease was as follows: 6% in ischemic heart disease, 7% in Kawasaki disease, 11% in hypertrophic cardiomyopathy (HCM), 18% in dilated cardiomyopathy (DCM) and 33% in arrhythmogenic right ventricular dysplasia (ARVD). Except for patients with HCM, the segments of the ventricles, where the fatty components were detected, agreed well with the segments with asynergy in left ventriculography and/or the segments with perfusion defect in T1 myocardial scintigraphy. Thus, ischemic fatty degeneration was considered to be a main factor in the production of intramyocardial fatty components in these diseases. The focus of arrhythmia was sometimes detected in the segments with intramyocardial fatty components in DCM and ARVD cases. It is suspected that intramyocardial fatty components sometimes produce arrhythmia in these diseases.

Magnetic resonance imaging of pericardial malignant mesothelioma

Magnetic resonance imaging of pericardial malignant mesothelioma in two patients is reported. Magnetic resonance imaging clearly depicted the tumor location and expansion, and was useful in delineating the anatomic extent of pericardial malignant mesothelioma.

[Influence of hypertensive left ventricular hypertrophy on detection of ischemic area with exercise thallium-201 myocardial scintigraphy]

Sixty-four patients with single left anterior descending artery disease having effort angina (group A: 40 patients without hypertension, group B: 10 patients with hypertrophic hypertension, group C: 14 patients with non-hypertrophic hypertension) were assessed the influence of hypertensive left ventricular (LV) hypertrophy on detection of ischemic area. The criterion of hypertrophy by two-dimensional echocardiography was > 12 mm in the wall thickness of interventricular septal or posterior wall. Population in Group B might show low detectability in ischemic area by 201Tl myocardial scintigraphy (positive thallium rate 60%, defect score 2.7 +/- 3.6), and high lung thallium uptake and high frequence of ECG positive among three groups. In semiquantitative analysis, the washout rate of the posterolateral wall and %RD (delayed %uptake-initial %uptake) of the septal wall in patients with Group B were lowest among three groups. However, the washout rate in the septal wall against the posterior wall, and the initial %uptake and the delayed %uptake of the septal wall were not significantly different among three groups. We could conclude that the decreased washout rate in nonischemic area with hypertensive LV hypertrophy might make the ischemic area masked.

[Raise up 99mTc-HMPAO brain SPECT for detecting the changes in cerebral perfusion pressure]

99mTc-HMPAO crossed the blood brain barrier instantly in proportional to cerebral blood flow. Raise up stress and supine resting 99mTc-HMPAO with brain SPECT was devised for detecting abnormal response in the changes of cerebral perfusion pressure. Asymmetric ratio in the middle cerebral artery area in patients with internal carotid artery occlusion (n = 5) was changed significantly from 0.82 +/- 0.06 to 0.90 +/- 0.06 and that of normal (n = 5) was not changed from 0.94 +/- 0.03 to 0.95 +/- 0.01. Raise up 99mTc-HMPAO brain SPECT enhanced the detectability in abnormality of regional cerebral blood flow and visualized the dys-autoregulated area during blood pressure falls.

[Growth rate of abdominal aortic aneurysms as measured by Computerized tomography]

To evaluate the growth rate of abdominal aortic aneurysms, sequential computed tomography (CT) examinations were performed on 125 nonoperated patients (M/F 101/24, mean age 67 +/- 8 years, 129 lesions) at intervals of at least 6 months. Growth rates of aneurysms were obtained by subtracting the first from the last diameter and adjusting for examination interval. Mean growth rate was 0.28 +/- 0.26 cm/year. Aneurysms with an initial diameter exceeding 4 or 5 cm showed significantly faster growth than smaller aneurysms. There was no significant correlation between growth rate and atherosclerogenic factors, but systolic blood pressure was significantly higher in patients whose aneurysms ruptured. Our study showed quantitatively that aneurysms with a large diameter have a rapid growth rate, the growth rate of infrarenal aneurysms is significantly faster than that of suprarenal aneurysms, and blood pressure control is important to prevent rupture.

[Usefulness of 201Tl myocardial scintigraphy after dipyridamole infusion in patients with atherosclerotic vascular disease]

To determine the utility for detecting ischemic heart disease (IHD), Dipyridamole thallium myocardial images (DIP-Tl) have been performed in the 103 patients with atherosclerotic vascular disease who can't exercise fully. Of 103 patients, there were 36 patients with arteriosclerosis obliterans (ASO), 31 patients with aneurysm of the abdominal aorta (AAA), 24 patients with aneurysm of the thoracic aorta (TAA) and 12 patients with dissecting aortic aneurysm (DAA). Clinical evidence of IHD was found in 20 patients with ASO, 10 with AAA, 7 with TAA and 4 with DAA respectively. Positive evidence of DIP-Tl was identified in 66% of 41 patients who had clinical evidence of IHD, and particularly in the patients with AAA (80%) and ASO (65%). On the other hand, in the patients without clinical evidence of IHD, positive evidence of DIP-Tl was identified in 19% of 62 patients and particularly in the patients with AAA (39%). In all patients, the percentage of the positive DIP-Tl ratio was 38%. And, when the 38% patients of the positive DIP-Tl were added to the patients of the negative DIP-Tl who had clinical evidence of IHD, almost half patients (51%) were considered to be complicated with IHD. This study suggests that the atherosclerotic vascular disease is highly complicated with IHD and DIP-Tl is useful to detect IHD.

Visualization of posture-dependent cerebral blood flow in a patient with Takayasu's disease by means of 99mTc-HMPAO brain single photon emission tomography

A case of Takayasu's disease in a 22-year-old woman who complained of severe fainting attacks is presented. Bilateral obstruction of the cervical arteries was confirmed by digital subtraction angiography. Preoperative technetium-99m hexamethylpropylene amine oxime brain SPET in the sitting position showed bilateral hypoactivity in the temporoparietal areas. Subtraction brain SPET showed slightly increased activity in the lying position. The patient has had no fainting attacks since bypass surgery. Postoperative 99mTc-HMPAO brain SPET in the sitting position showed normal activity except in the right temporoparietal area. This area was filled in the lying position. 99mTc-HMPAO brain SPET is the only technique that can visualize the cerebral blood flow in any position, this capability deriving on the fact that the distribution of 99mTc-HMPAO in the brain is fixed in the first 2-3 min following injection. The use of both sitting and lying 99mTc-HMPAO brain SPET is very useful for detecting an abnormality (i.e. an inhomogeneous response due to the fall in perfusion pressure) that could not be seen if the cerebral blood flow were to be assessed only in the lying position.

Effects of carbon dioxide on preoptic thermosensitive neurons in vitro

Effects of carbon dioxide (CO2) on the firing rates of preoptic thermosensitive neurons were examined in rat brain slice preparations. The perfusing medium was saturated with gas mixtures consisting of 90% O2 and one of various concentrations (5%, 6.3%, 7.5%, and 10%) of CO2 balanced with N2. The medium containing 5% CO2 was used as control. Most preoptic neurons were inhibited during application of a high CO2 medium. An excitatory effect of CO2 on a small number of neurons was also significant, although this was weak and transient compared to the inhibitory effect. Thermosensitivities of the neurons did not correlate with their CO2 sensitivities. The influence of CO2 tended to be more evident at higher temperatures. We conclude that the direct effect of CO2 on PO thermosensitive neurons as well as on thermally insensitive neurons is mainly inhibitory.

Thermally induced salivary secretion in anesthetized rats

Effect of thermal stimulation on salivary secretion was examined in urethane anesthetized (i.p., 1.0 g/kg) rats. First, rectal temperature (Tre) was maintained at various levels by warming the whole trunk with a heating blanket. Copious salivary secretion occurred when Tre reached a threshold value above 40 degrees C, which is considerably higher than the threshold for tail vasodilation. Local warming of the scrotum, face, or hypothalamus also elicited salivary secretion, but only if Tre was in a limited range just below the threshold temperature at which Tre alone would induce salivary secretion. The higher the Tre within that limited range, the lower the temperature of the site locally warmed at which salivary secretion began. Changes in temperature of the abdomen, not including the scrotum, modulated the salivary secretion elicited by scrotal warming. Hypothalamic and scrotal temperatures interacted with each other to affect salivary secretion. Temperature signals from both core and periphery thus appear to be integrated in bringing about salivary secretion. Thermally induced salivary secretion may function as a basis for saliva spreading behavior observed in rats in a hot environment.

Responses of thalamic and hypothalamic neurons to scrotal warming in rats: non-specific responses?

Activities of thalamic and hypothalamic neurons in response to scrotal temperature change were investigated in urethanized (1.2-1.5 g/kg) rats with special attention to changes in cortical electroencephalogram (EEG). Somatosensory relay neurons were identified electrophysiologically in the ventrobasal complex (VB) of the thalamus. These neurons had tactile receptive fields in areas outside the scrotum. Forty out of 44 of these neurons responded to scrotal warming by increase in firing rate. The responses occurred abruptly at threshold temperatures ranging from 31 to 40 degrees C (switching response) with simultaneous changes in EEG from high to low voltages (desynchronization). In both the thalamus and the hypothalamus, neurons excited or inhibited by scrotal warming were also excited or inhibited, respectively, by noxious stimulation that produced EEG desynchronization. Neurons showing no response to scrotal warming were not affected by noxious stimulation. In deeply anesthetized (2.5 g/kg urethane) rats, VB relay neurons responded to tactile stimulation of their receptive fields, but scrotal warming produced no change in either EEG or activities of thalamic and hypothalamic neurons. These facts suggest that the responses of thalamic and hypothalamic neurons to scrotal warming may be 'non-specific'. Most thalamic and hypothalamic neurons showing switching responses did not appear to mediate specific information concerning scrotal skin temperature.