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K Houkin

Publications and source records attributed to K Houkin.

At least 19 recordsLinked to original sources
PubMed1992

[Clinical application of phase contrast angiography].

"Phase Contrast Angiography" is a new technique of Magnetic Resonance Angiography as reported by Dumoulin CL et al. Using this technique, we can obtain images of vessels (angiograms) without injection of contrast medium. We present the results of phase contrast angiography on cerebral and spinal vascular disease. We utilized the General Electric SIGNA, 1.5 tesla NMR. One hundred and ninety-one cases of cerebral and spinal vascular diseases were scanned using phase contrast angiography. Included were 90 cases of occlusive vascular disease, 16 cases of moyamoya disease, 39 cases of arteriovenous malformation, and 28 aneurysms. The phase contrast angiography uses flow encoding gradient pulses, which impart a velocity-dependent phase shift to the transverse magnetization of moving spins. The resulting image contains only information from the moving spins; while information from stationary tissue remains suppressed. In cases using 3-D angiogram, we made 32 images 6 degrees apart in their projection direction and displayed them on a video terminal. We were able to visualize occlusions of vessels, aneurysms, bypassed vessels, and abnormal vessels of arteriovenous malformations. Retrospective evaluation comparing phase contrast angiography with conventional angiography of the stenotic findings on the horizontal portion of middle cerebral arteries (64 vessels of 32 patients), resulted in a false positive ratio of 39.1%. We obtained clinically valuable results regarding the hydrodynamics of patients using "phase contrast angiography" non-invasively. These results reveal not only "anatomical" images of vessels, but also "functional" images, which are sensitive to the pattern of the blood flow. This study would strongly suggest that phase contrast angiography presents a valuable tool for the clinical diagnosis of cerebral and spinal vascular diseases.

Cerebral Angiography↗
PubMed1992

[Evaluation of cerebral blood circulation using fast magnetic resonance imaging (turbo-FLASH)].

In its initial stage of development, poor time resolution was supposed to be inevitable for magnetic resonance imaging (MRI). The development of the gradient echo technique, however, has made an opening for a breakthrough to a fast MRI technique. However, conventional gradient echo technique is not fast enough to disclose the cerebral blood circulation. A new technique (turbo-FLASH), which combines gradient echo and preparation pulse, has opened the door to a true dynamic (high time resolution) MRI. The authors performed a basic study of this new fast imaging technique (Turbo-FLASH) for the evaluation of cerebral blood circulation. Using this dynamic MRI, the conventional Gd-DTPA administration (0.1mmol/kg, intravenous manual administration) has produced sufficient contrast to reveal a difference of the extent of enhancement between normal gray matter and white matter. In patients of cerebral infarction, the infarcted brain does not show any significant increase of signal intensity after the administration of contrast medium, whereas the normal brain shows a sharp increase of signal intensity after the administration of contrast medium. Indeed, many puzzling questions remain to be solved for clinical application of this new dynamic MRI. For example, the optimal quantity of contrast medium and optimal parameters for this sequence (T1 weighted or T2 weighted?) are still unknown. But, in any case, this dynamic MRI is expected to be a clinically powerful tool for the evaluation of cerebral blood flow.

Brain↗
PubMed1992

[Quantitative analysis of cerebrospinal fluid dynamics in syringomyelia using cine MRI with pre-saturation].

Some reports show the qualitative analysis of cerebrospinal fluid (CSF) pulsation in the subarachnoid space and the syrinx using cine magnetic resonance imaging (MRI). However, few reports studied the quantitative analysis of CSF pulsation. We report here the results of quantitative analysis of CSF pulsation using the cine MRI with pre-saturation pulse. Using flow phantom, we calibrated the correlation between the true velocity and calculated velocity acquired from the movement of pre-saturated low signal. Three cases of syringomyelia with Chiari malformation, two cases of traumatic syringomyelia, and three normal volunteers were examined using this technique, and we could obtain time-velocity curves of CSF in both subarachnoid spaces and syrinx. Although obvious pulsation of CSF was observed in the syrinx of all Chiari malformations, no pulsation of CSF was observed in the syrinx of traumatic syringomyelia. CSF in the syrinx moves upward in the early systolic cardiac cycle, downward in the systolic cycle, and upward again in the diastolic cycle. Patterns of CSF pulsation in syrinx were similar to those in the subarachnoid space, but "phase" of these pulsations differed from case to case. These results suggest the close relationship between CSF pulsation in the syrinx and CSF obstruction at the cranio-vertebral junction. Dissociation of the "phase" of CSF pulsation in the syrinx and subarachnoid space may be significant in the analysis of the pathogenesis of syringomyelia.

Adult↗
PubMed1992

[Anatomical analysis of the sources of somatosensory evoked fields (SEFs) using 3D-MRI].

We have recorded short latency somatosensory evoked magnetic fields (SEFs) to left median nerve stimulation in three healthy subjects. The locations of the deduced dipole sources were projected onto the 3-Dimensional magnetic resonance imaging (3D-MRI) of the individual subjects providing an anatomical localization. We found that the deduced sources were located at the primary sensorimotor hand area on the posterior surface of the central sulcus, at an average depth of 26mm (11mm) from the scalp (brain surface). This technique that combined MEG with 3D-MRI was able to precisely determine source locations and analyze the relationships between dipole sources and brain structures. By using this technique, we can confirm functional anatomy of the brain noninvasively, and obtain much useful information preoperatively and during operation.

Adult↗
PubMed1991

Rebound alkalosis and persistent lactate: multinuclear (1H, 13C, 31P) NMR spectroscopic studies in rats.

Intracellular pH levels of infarcted brain determined by phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy disclosed a notable phenomenon. The acidotic brain pH seen in the acute stage of infarction was observed to rebound into the alkalotic range in the subacute phase before returning to the normal range in the chronic phase. This "rebound alkalosis" which was usually observed between the 24th and the 48th hour after experimental induction of infarction in rats was accompanied by significant lactate levels as detected by proton NMR spectroscopy. Analysis of the satellite methyl resonance of 13C-lactate using high-resolution proton NMR spectroscopy after 13C-glucose infusion indicated that no lactate was produced in the subacute phase of infarction and that the lactate detected during this phase must have been generated prior to this phase of infarction.

Alkalosis↗
PubMed1991

Acute aggravation of subdural effusion associated with pachymeningitis carcinomatosa: case report.

The authors present a case of acute aggravation of subdural effusion associated with pachymeningitis carcinomatosa. Microscopic examination of a surgical specimen revealed diffuse involvement of the dura mater by a metastatic adenocarcinoma in which the tumor cells invaded venules located in the areolar layer in particular. The rapid increase in capillary transmural pressure resulted in extravasation of plasma components, causing an increase in subdural effusion.

Adenocarcinoma↗
PubMed1991

Clinical application of proton magnetic resonance spectroscopy to cerebral ischemia.

Proton magnetic resonance spectroscopy (MRS) with the depth resolved surface coil spectroscopy technique and the 1331-2662 water suppression method was used to examine two cerebral ischemia patients and 10 normal volunteers. In all cases, N-acetyl-aspartate, creatine, phosphocreatine, and residual lipid were clearly observed. No lactic acid peak was observed in normal volunteers, but a large lactic acid peak appeared in the early stage of cerebral ischemia. This MRS abnormality was observed before abnormalities appeared in conventional imaging such as computed tomographic scanning and magnetic resonance imaging.

Adult↗
PubMed1991

[Longitudinal change of H-1 spectroscopy in cerebral infarction].

Longitudinal change of the proton spectroscopy was observed in 2 cases of cerebral infarction. Proton spectra was acquired utilizing stimulated echo acquisition mode (STEAM). In acute stage, the increase of lactic acid and decrease of N-acetyl-aspartic acid (NAA) was observed prior to the appearance of abnormality in imagings such as magnetic resonance imaging and computer tomography. The increase of lactic acid was observed in subacute stage and chronic stage (in severe case). The decrease of NAA persisted in chronic stage. The increase of lactic acid and decrease of NAA indicate a damage of the ischemic tissue. The degree of the decrease of the NAA seems to be a reasonable indicator of the viability of the damaged tissue. The proton spectroscopy is a powerful modality for the evaluation of the extent of tissue damage caused by the ischemic insult.

Aged↗
PubMed1991

[Three-dimensional MR brain image using volume rendering method].

3-dimensional image reconstructed from the data of computer tomography has provided useful informations for the pre-operative evaluation in the field of neurosurgery and plastic surgery. However CT has failed to visualized the 3-dimensional surface image of the central nervous system. On the other hand the progress of high-speed data acquisition technique and 3-dimensional fourier transformation has enabled the practical 3-dimensional image using magnetic resonance imager. However for the visualization of a pure surface image of the brain and spinal cord a sophisticated method and special image work station has been necessary. The authors describe a technique for the pure surface image of the brain and spinal cord using a normal mini-computer system and magnetic resonance imager. This image has a good correlation to the macroscopic anatomical brain surface (sulci and gyri).

Brain↗
PubMed1991

[Stab wounds of the spinal cord by a kitchen knife: report of a case].

A case of spinal cord injury due to stab wounds by a kitchen knife is presented. A 41-year-old male was hospitalized because of spinal cord injury resulting from stab wounds inflicted with a kitchen knife in the posterior cervical area. Neurological examination on admission showed paraplegia, disappearance of deep tendon reflex in both lower extremities, sensory disturbance below T1 level, left Horner's syndrome and urinary disturbance. In addition to these symptoms cerebrospinal fluid was leaking from the wounds. An emergency operation was performed. After laminectomy of C7 and T1, we found that the spinal cord was almost completely split at C7/T1 level. Dural plasty was performed. Neurologically, sensory disturbance was slightly improved at 4 months after the injury. Initial MRI (TR: 200 msec, TE: 20 msec) revealed high intensity at C7/T1 level which was damaged by the kitchen knife. MRI 5 months after the injury revealed low intensity on T1 weighted imaged, high intensity on T2 and proton weighted image. The occurrence of the spinal cord injury due to stab wounds by a kitchen knife is very rare in Japan. MRI is useful in the diagnosis of stab wounds of the spinal cord.

Adult↗
PubMed1990

Persistent high lactate level as a sensitive MR spectroscopy indicator of completed infarction.

Serial proton (1H) and phosphorus-31 (31P) magnetic resonance (MR) spectroscopy of cerebral infarction was performed in rats to assess the sensitivity of these techniques for use in clinical cerebral infarction. In this experimental chronic infarction model, 31P spectroscopy tended to return to a "normal" pattern within 24 hours after induction of infarction in spite of pathologically proven completed infarction and, therefore, appeared not to be sensitive enough for clinical application. On the other hand, proton spectroscopy invariably showed persistent high lactate levels and was capable of distinguishing completed infarction from reperfused recovered brain. Persistent high lactate levels appear to be a good MR spectroscopic indicator of completed infarction.

Animals↗
PubMed1990

[Proton and phosphorus-31 nuclear magnetic resonance spectroscopy in experimental cerebral infarction in rats].

Longitudinal study of metabolic change after cerebral infarction was done using nuclear magnetic resonance spectroscopy (MRS). Localized completed infarction model induced by intra-cranial ligation of the middle cerebral artery and extra-cranial ligation of common carotid artery in rats was utilized. In acute study the proton MRS revealed a sharp increase of lactic acid but the phosphorus -31 MRS did not show prominent changes. This increase of lactic acid persists 24 hours after the induction of infarction. In chronic study the spectroscopic pattern of the infarcted brain showed minimum difference from the control normal brain. However the signal intensity of phosphomonoester was significantly higher in the infarcted brain. Our study in acute phase suggests that the proton MRS is a sensitive probe to detect an early metabolic deterioration induced by ischemic insult. And the increase of phosphomonoester in chronic infarcted brain may imply that a gliosis seen in chronic infarction has a metabolic resemblance to neonate brain and neoplasm.

Animals↗
PubMed1989

Intrauterine fetal brain NMR spectroscopy: 1H and 31P studies in rats.

Fetal brain metabolism was investigated in utero noninvasively using multinuclear nuclear magnetic resonance spectroscopy in rats at two representative prenatal stages: early (17-18 days) and late (20-21 days) stages. Phosphorus-31 (31P) spectroscopy revealed that phosphocreatine is significantly lower in the early stage and increases to the level of early neonates by the late prenatal stage. Intracellular pH at the early stage was found to be strikingly high (7.52 +/- 0.21) and decreased to a level similar to that of neonates by the late stage (7.29 +/- 0.07). Phosphomonoester levels at both stages were similar to the values reported for early neonates. Water-suppressed proton (1H) spectroscopy demonstrated a distinctive in vivo fetal brain spectral pattern characterized by low levels of N-acetyl aspartate and high levels of taurine. High-resolution proton spectroscopy and homonuclear chemical-shift correlate spectroscopy of brain perchloric acid extracts confirmed these in vivo findings. In vitro 31P spectroscopy of acidified chloroform methanol extracts showed the characteristic membrane phospholipid profiles of fetal brain. The phosphatidylethanolamine (PE)-to-phosphatidylcholine (PC) ratio (PE/PC) did not show significant changes between the two stages at 0.40 +/- 0.11, a value similar to that of early neonates.

Animals↗
PubMed1989

Cortical spectroscopy: localized spectroscopy of the cerebral cortex in rats.

A method for obtaining nuclear magnetic resonance (NMR) spectroscopic signals confined to the cerebral cortex in rat using a cortical coil constructed based on the principles of the zig-zag coil is described. We obtained 31P NMR spectra of normal cerebral cortex and cold-induced injured cortex using this cortical coil. The cortical coil clearly demonstrated an increase in inorganic phosphate (Pi) confirmed to cerebral cortex which, by contrast, the conventional planar surface coil failed to detect. There are significant metabolic differences between cortex and subcortical tissues. The technique described here, capable of assessing cortical metabolism in vivo without contamination by the underlying tissue, has substantial application to studies of cerebral metabolism.

Animals↗
PubMed1989

31P magnetic resonance spectroscopy of chronic cerebral infarction in rats.

The chronological changes in the pattern of 31P magnetic resonance spectroscopy (MRS) associated with cerebral infarction were studied in rats. 31P MRS of chronic infarction (1 month after induction of infarction) clearly showed a pattern distinct from that of normal brain. In chronic infarction, the relative phosphomonoester (PME) level was found to be significantly higher and relative phosphocreatine (PCr) level significantly lower compared to normal brain. The intracellular pH and the relative inorganic phosphate (Pi) level did not show any significant differences. Histological examination indicated that the 31P MRS pattern of chronic infarction reflects gliosis.

Animals↗