The effect of muscle hypertrophy on the relationship between magnetic resonance (MR) relaxation time and muscle fibre composition was investigated. Relaxation time and muscle fibre composition were measured in five subjects before and after a 20-week period of strength training. Muscle fibre composition in all subjects exhibited a significant shift to a predominance of fast-twitch (FT) fibres as a result of 20-week strength training (% area FT fibres: mean values from 49.8%, SD 17.9% to 57%, SD 5.6%; P<0.05). Longitudinal relaxation time (T1) and transverse relaxation time (T2) were prolonged significantly after strength training (T1 mean values from 334.9 ms, SD 13.6 to 359.0 ms, SD 9.0, P<0.001; T2 from 27.5 ms, SD 0.9 to 30.8 ms, SD 2.3, P<0.05). A constant relationship was observed in changes caused by strength training in muscle fibre composition (% area FT) and relaxation time, with a high correlation obtained between both parameters. These results indicate that MR relaxation time can be used for non-invasive estimation of muscle fibre composition.

16th Annual Meeting of the Japanese Neuroradiological Society* Tokyo, 27-28 February, 1987 Special Lecture: 1. Professor Dr. reed. Hans-Joachim Kxetschmann, Hannover, FRG "Neuroanatomy and Neuroimaging" 2. Professor Dr. reed. Wolfgang Weinrich, Hannover, FRG "Neurological Dysfunction and Neuroimaging" I A-I, Investigation of crossed cerebellar diaschisis by X-ray CT; its relations with cerebral disease T. Yagishita 1, 3, A. Nakamori 2, S. Kojima 3, and K. Hirayama 3. 1Department of Neurology and 2Department of Radiology, Comprehensive Stroke Center, Kanagawa Rehabilitation Hospital, Atsugi, and 3Department of Neurology, Chiba University of Medicine, Chiba We investigated by X-ray CT the occurrence of crossed cerebellar atrophy in patients who suffered from ipsilateral cerebrovascular disease. Crossed cerebellar atrophy was diagnosed in 6 out of 137 patients with either large cerebral infarcts in the area of the middle cerebral artery (MCA area) or localized in the putamen or thalamus. When the blood flow of the right and left cerebellar hemispheres of 17 patients without crossed cerebellar atrophy was compared by dynamic CT, low blood flow in one cerebellar hemisphere was found in 9 cases. Contralateral damage was shown in the putamen (4 cases) and thalamus (1 case), a small infarct in the MCA area (3 cases) and a moderate or broad infarct in MCA area (1 case). All these infarcts were in their acute or subacute stage. Both in cases of crossed cerebellar atrophy and of low blood flow in the contralateral cerebellar hemisphere, the putamen and thalamus, which are adjacent to internal capsule, were damaged. These findings suggest that transsynaptic degeneration of cortico-ponto-cerebellar pathways might be one of causative factors of crossed cerebellar atrophy and low blood flow in the contralateral cerebellar hemisphere. 1 A-2. Five cases of interhemispheric cysts with callosal defect Neuroradiological evaluation and embryological consideration H. Utsunomiya 1, H. Toyoshima 1, T. Hayashi a, E. Honda 2, T. Hashimoto 3, and T.Okudera 4. Departments of 1Neuroradiology, 2Neurosurgery, 3Neonatology, St Mary's Hospital, Kurume, and 4Department of Radiology, Fukuoka University School of Medicine, Fukuoka We presented five cases of interhemispheric cysts (IHC) associated with callosal defect in neonates. The following neuroradiolog* Pres iden t : Kazuo Takeuchi, M.D., Director and Professor, Department of Neurosurgery, Kyorin University School of Medicine, Shinkawa 6-20-2, Mitaka City, Tokyo, 181-Japan 1A-2A: speech 1 B-2 B: scientific presentation ical examinations were performed: CT scan in all cases, MRI in 2 cases, cerebral angiography in 3 cases, and metrizamide administrated CT in 2 cases. According to the morphological classification by Probst (1973), they were identified as non-communicating IHC, 1 (case 1) and communicating IHC, 4 (cases 2-5). The noncommunicating cyst was isolated from ventricular system; the others consisted of elevation of the third ventricle with callosal agenesis and were associated with increased intraventricular pressure. The classification of the communicating IHC was further divided into two: secondary (case 2) and primary IHC (cases 3-5), with and without formation of the falcotentorium, respectively. The stage of cyst formation could be determined by the presence or absence of the falcotentorium as well as Galenic drainage. Thus, the primary and secondary IHC were formed in early and late stages of embryonic development respectively. Cases 4 and 5, the primary IHC, also revealed Galenic dysgenesis at cerebral angiography. All patients had hydrocephalus. Cases 4 and 5 had the further complication of interparietal cephaloceles which were continuous with large expanded IHC replacing the midline cerebral mantle. Thus the morphological characteristics of these two cases well corresponded to Yokota's proposed "midline porencephaly" (1979). All the communicating IHC cases received ventricular shunts, whereas the non-communicating IHC was surgically opened and were confirmed as glioependymal by microscopic examination. 1 A-3. Interhemispheric cyst with agenesis of corpus callosum and malformation of ACA M. Nakamura 1, M. Imanishi 1, K. Kinugawa 1, and T. Kamino 2. 1Department of Neurosurgery, Matsubara City Hospital, Matsubara and ZDepartment of Neurosurgery, Kyoritsu Hospital Interhemispheric cysts are considered to be rare and commonly communicate with the ventricular system. We report a case of interhemispheric cyst without communication with the ventricular system, complicated by agenesis of corpus callosum, and malformation of the anterior cerebral artery. The case is a 35-year-old man, who was examined in our clinic for headache. He had neither particular family history nor relevant past history, and showed no obvious abnormal findings at neurological examination. CT revealed a well-demarcated low attenuation area in frontal interhemispheric cistern, which metrizamide CT proved to be a cyst with no communication with the ventricular system, and in which MRI identified agenesis of corpus callosum. Cerebral angiography revealed 3 anterior cerebral arteries, a large median ACA named accessory ACA by Baptista and bilateral small ACA. It is known that not only corpus callosum, but also anterior cerebral artery and anterior communicating artery are formed as early as the 6th fetal week. This case is regarded as one in which an interhemispheric cyst already existing at about the 6th fetal week, provoked not only agenesis of corpus callosum but also the formation of accessory ACA.

To evaluate changes in muscle energetics following endurance training, we measured phosphorus-31 nuclear magnetic resonance (31P NMR) spectra on rat muscle in vivo before and after training in the same animals. The endurance training lasted for 3 months. The31P NMR spectra were obtained serially at rest, during exercise by electrical stimulation, and during recovery. Intramuscular phosphocreatine (PCr), inorganic phosphate (Pi, adenosine 5′-triphosphate (ATP) and pH were determined from the NMR spectra. The ratio of PCr : (PCr + Pi) at rest showed no difference between the trained and control groups even after 3 months of training. During exercise, however, this ratio was significantly higher in the trained group than in the control group. The ratio also recovered more rapidly after exercise in the trained group. The intramuscular pH decreased slightly by approximately 0.1 pH unit during exercise but did not show a significant difference between the groups. These results indicated that endurance training of 3 months duration improved the ATP supply system in the muscle. They also demonstrated that31P NMR is a potent method for evaluating the effects of training in the same individuals.

Our initial studies in animal experiments using K-edge energy subtraction transvenous coronary angiography at the Photon Factory were undertaken using an iodine filter for energy switching combined with an X-ray image intensifier. In vivo subtracted images of coronary arteries in dogs were obtained in the form of motion pictures. However, the image quality was not good for medical examinations because the contrast material was highly diluted. A new image detector with a fluorescent-screen lens-coupling approach has been developed to take high quality images. By using the new detector in place of the X-ray image intensifier, image quality has markedly increased in coronary angiography.

A high-spatial resolution imaging system employing lens coupling between a fluorescent screen and a HARPICON™ camera was evaluated as a digital mammographie imaging device. A mammographie image on the fluorescent screen is focused on the photoconductive layer of the high sensitivity HARPICON tube by lenses. The limiting spatial resolution in the 1024 × 980 pixel mode of the camera is about 60 um at an input field of 50 × 50 mm on the screen. Images of a standard mammographie phantom were taken at the monochromatized X-ray energy of 20 keV. The images showed smaller specks of microcalcifications and tumor masses than those discernible in images obtained with a conventional screen-film mammography unit.

A HARPICON(TM) camera has been applied to a digital angiography system with fluorescent-screen optical-lens coupling. It uses avalanche multiplication in the photoconductive layer for high-sensitivity imaging. The limiting spatial resolutions in the 1050 scanning-line mode of the camera are about 30 and 50 micro m at input field sizes of 20 x 20 and 50 x 50 mm on the screen, respectively. For high-speed imaging, the 525 scanning-line mode at a rate of 60 images s(-1) can be selected. High-quality images of coronary arteries in dogs were obtained by intra-aortic coronary angiography and superselective coronary angiography using a single-energy X-ray above the iodine K-edge energy.

A high-sensitivity HARPICON camera was developed for medical X-ray imaging using a fluorescent screen. It is an avalanche-multiplication-type image pick-up tube and is 32 times more sensitive than conventional tubes. The camera also has a wider dynamic range than conventional medical-imaging cameras because a maximum output signal current of 2.3 muA is obtained and, in high-illumination-intensity regions, photocurrent is not proportional to illumination intensity. The fluorescent screen is an intensifying screen of the type used for radiographic screen-film combinations in medical examination. An X-ray image on the screen is focused on the photoconductive layer of the pick-up tube using a coupling lens with f/0.65. Experiments were performed using monochromated X-rays at the Photon Factory. An image of a spatial resolution test chart was taken in a 525 scanning-line mode of the camera. The chart pattern of 5 line-pairs mm(-1 )(spatial resolution of 100 mum) was observed at an X-ray input field of 50 x 50 mm. Real-time digital images of the heart of a 12 kg dog were obtained at a frame rate of 60 images s(-1) after injection of a contrast medium into an artery. The images were stored in digital format at 512 x 480 pixels with 12 bits pixel(-1). High-spatial-resolution and high-contrast images of coronary arteries were obtained in aortography using X-rays with energy above that of the iodine K edge; the image quality was comparable with that of conventional selective coronary angiography.

Rationale and Objectives. For intravenous (Ii) coronary arteriography, a real-time two-dimensional (2D) imaging system is being developed using above-K-edge monochromatic X-rays alone. The potential diagnostic value of this system was examined in the current study.Methods. The angiographic system consisted of an asymmetric silicon (311) monocrystal, an image intensifier, and a charged-coupled device camera. It was constructed at the beam line of the Tristan Accumulation Ring, Monochromatic X-rays of 33.32 keV were used, and each image was recorded over 2 msec.Results. Ventricular wall motion and the anatomy of the coronary arteries could be seen in dogs by sequential images obtained without subtraction. The left anterior descending coronary artery, left circumflex coronary artery, and right coronary artery and the branches of these vessels were observed. The parts of the coronary arteries overlapping the aorta and left ventricle were revealed somewhat during washout of the contrast material.Conclusion. For a 2D imaging system, monochromatic IV coronary angiography using an energy above the iodine K-edge might be able to image the coronary arteries without subtraction. However, the image quality needs to be improved by increasing the X-ray flux, decreasing background radiation scatter from the object, and decreasing contamination with 99-keV X-rays.

Iodine K-edge subtraction techniques using monochromatized X-ray have been investigated at several synchrotron radiation facilities for transvenous coronary angiography. We developed an iodine-filter imaging system for real-time imaging. A combination of the iodine filter and a single energy monochromatized X-ray produces two-energy images for the iodine K-edge subtraction technique. An X-ray exposure system consists of the iodine filter and a monochromator. X-ray energies are switched by the filter chopping of the X-ray beam. A detector consists of an X-ray image intensifier and a video camera. An oscillating mirror is installed between the collimating lens and camera lens in an image distributor. Each image that corresponds to the iodine- and aluminum- (non-iodine-) filtered images is focused side by side on the photoconductive layer of the camera tube by the oscillating mirror.

A new type of real-time imaging system was developed for transvenous coronary angiography. A combination of an iodine filter and a single energy broad-bandwidth X-ray produces two-energy images for the iodine K-edge subtraction technique. X-ray images are sequentially converted to visible images by an X-ray image intensifier. By synchronizing the timing of the movement of the iodine filter into and out of the X-ray beam, two output images of the image intensifier are focused side by side on the photoconductive layer of a camera tube by an oscillating mirror. Both images are read out by electron beam scanning of a 1050-scanning-line video camera within a camera frame time of 66.7 ms. One hundred ninety two pairs of iodine-filtered and non-iodine-filtered images are stored in the frame memory at a rate of 15 pairs/s. In vivo subtracted images of coronary arteries in dogs were obtained in the form of motion pictures.

Tokyo Hitachi Hospital has used a hospital-wide PACS for these two years, that is probably the first experience in the world. The system runs 100Mbps optical fiber network over the hospital including outpatients clinics, wards, one treatment room, and radiology department with 11 image workstations and an image database. We have managed about 400,000 image of about 10,600 patients so far. The system has been designed for use in wards, clinics, treatment room and conference room. So physicians and engineers have made many discussions to realize these viewpoints. A complete automation for implementation of the system and the integration of Hospital Information System (HIS) with PACS has been discussed. The hospital-wide PACS has proven to be more usefull for image diagnosis and more effective for image management than that of PACS inside radiology deaprtment in the hospital. An organic integration of PACS with HIS is strongly required for the hospital-wide PACS.

A new type of subtraction imaging system was developed using an iodine filter and a single-energy broad bandwidth monochromatized x ray. The x-ray images of coronary arteries made after intravenous injection of a contrast agent are enhanced by an energy-subtraction technique. Filter chopping of the x-ray beam switches energies rapidly, so that a nearly simultaneous pair of filtered and nonfiltered images can be made. By using a high-speed video camera, a pair of two 512 × 512 pixel images can be obtained within 9 ms. Three hundred eighty-four images (raw data) are stored in a 144-Mbyte frame memory. After phantom studies, in vivo subtracted images of coronary arteries in dogs were obtained at a rate of 15 images/s.

To investigate changes in left atrial morphology and dimensions during the cardiac cycle, the atrium was visualized by intravenous digital subtraction angiography (DSA). The study subjects consisted of 22 male patients whose average age was 54.5 +/- 8.6 years. They had ischemic heart disease without mitral valve disease and were in sinus rhythm. They were 11 patients with old myocardial infarction (OMI group) and 11 who had chest pain without evidence of infarction (AP group). DSA was performed in the continuous mode. Contrast material (35 ml) was injected at a rate of 18 ml/sec via a catheter in the superior vena cava and subtraction images were obtained at a speed of 30 frames/sec in the right anterior oblique projection. The left atrial and left ventricular margins were traced manually, their areas were calculated, and fractional changes in area were analyzed. The left ventricular ejection fraction (LVEF) was calculated by densitometry. Cardiac catheterization was performed in 16 patients and the left ventricular end-diastolic pressure (LVEDP) and mean pulmonary arterial wedge pressure (PAWP) were measured. The entire left atrium was clearly imaged using DSA. Phase analysis of the time-area curves in the right anterior oblique projection revealed that the left atrial area was maximal during left ventricular end-systole (%LA1 = 100%), it decreased during early left ventricular diastole (%LA2), and then increased slightly again during mid-diastole (%LA3). After left atrial contraction, the minimum area was obtained (%LA4). The left atrium showed a two-stage decrease in the area due to passive emptying and active contraction during left ventricular diastole. Passive emptying (%LA1-%LA2) was significantly less in the OMI group than in the AP group (6.3 +/- 3.6 vs 13.3 +/- 4.8%, p < 0.01, respectively). In all 22 subjects, passive emptying correlated with LVEF (r = 0.70, p < 0.001) and LVEDP (r = -0.58, p < 0.05). There was no difference in active contraction (%LA3-%LA4) between the 2 groups (26.0 +/- 5.7% in the OMI group, 28.2 +/- 8.4% in the AP group), and it did not correlate with LVEF or LVEDP. The ratio of passive emptying to active contraction [(%LA1-%LA2)/(%LA3-%LA4)] correlated with LVEF (r = 0.63, p < 0.01). These findings suggested that impaired left ventricular diastolic function and a relative increase in atrial contraction were present in patients with a lower LVEF. The %LA4 correlated with LVEDP and PAWP (r = 0.65, r = 0.63, p < 0.01, respectively). In conclusion, DSA proved to be a useful method for investigating left atrial morphology and function.

PACS has been regarded as a system which will bring a new era to image handling, radiology departments and its services to other departments of the hospital. However, many recently held international conferences indicate that a worldwide consensus on 'what is PACS, why is PACS needed and who is PACS for' has not been established. Although the actual PACS implementation will vary among the countries and according to each situation, a worldwide consensus of PACS should be possible. This would help those involved to speed up the implementation of PACS. It is suggested that this consensus needs to be developed by convergence of three points of view; the availability, maturity and cost of the technologies on which PACS is built, the user requirements for PACS and standardization in PACS. These themes were the topics of the 2nd Japan-Nordic PACS Symposium which was arranged in Tampere, Finland, June 9-11th 1991. A summary of the papers and discussions of the symposium is produced in this paper.

A cine magnetic resonance (MR) imaging technique, involving the acquisition of kinematic sagittal images during knee movement, was used to evaluate 52 symptomatic knee joints. Results were compared with those obtained by means of static three-dimensional (3D) MR imaging. Twenty-seven of the 28 anterior cruciate ligament (ACL) tears and 22 of 24 normal ligaments were correctly identified at cine MR imaging for a sensitivity of 96% and a specificity of 92%. Static 3D MR imaging yielded a sensitivity of 71% and a specificity of 88%. All four posterior cruciate ligament tears were identified at cine and 3D MR imaging. For meniscal tears, cine MR imaging yielded a sensitivity of 48% and a specificity of 96%; the sensitivity and specificity for 3D MR imaging were 71% and 96%, respectively. Cine MR imaging proved to be more useful than static MR imaging in assessing the tightness of cruciate ligaments, especially of those that were partially torn, and in assessing the movement of meniscal-free fragments. The increased information obtained with cine MR imaging may warrant continued investigation and clinical application.

Regional cerebral perfusion was studied in three patients with the mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome, using single photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]iodoamphetamine (IMP). Accumulation of the tracer was relatively decreased in the parietooccipital regions and also in the frontotemporal regions after stroke-like episodes. However, quantitative regional cerebral blood flow (rCBF) measurement showed that rCBF was relatively well preserved even at these sites, and a hyperemic state was observed at the sites of normal accumulation. IMP SPECT may be useful in the diagnosis and assessment of the progress of the MELAS syndrome.

Regional cerebral perfusion was studied in three patients with the mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome, using single photon emission computed tomography (SPECT) with N-isopropyl-p-[123I]iodoamphetamine (IMP). Accumulation of the tracer was relatively decreased in the parietooccipital regions and also in the frontotemporal regions after stroke-like episodes. However, quantitative regional cerebral blood flow (rCBF) measurement showed that rCBF was relatively well preserved even at these sites, and a hyperemic state was observed at the sites of normal accumulation. IMP SPECT may be useful in the diagnosis and assessment of the progress of the MELAS syndrome.