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Biomedical subjects

H Anno

Publications and source records attributed to H Anno.

At least 19 recordsLinked to original sources
PubMed2001

Relationship between thrombolytic therapy and perfusion defect detected by Gd-DTPA-enhanced fast magnetic resonance imaging in acute myocardial infarction.

To study whether thrombolytic therapy affects Gd-DTPA-enhanced pattern and whether its pattern indicates myocardial viability, Gd-DTPA-enhanced magnetic resonance imaging (MRI) was performed in 43 patients with reperfused acute myocardial infarction 14.8+/-5.0 days after onset with breathhold scanning on a 1.5-T whole body system. The hypoenhanced area at 90 sec after contrast injection was defined as a perfusion defect (PD). Patients were divided into PD(+) and PD(-) groups. The PD was detected in 77.8% of patients treated with direct percutaneous transluminal coronary angioplasty (PTCA) and in 28.6% of patients treated by thrombolytic therapy with or without PTCA in the thrombolysis in myocardial infarction grade 3 group (p < 0.05). The myocardial wall was divided into seven segments based on the American Heart Association committee report. Wall motion of each segment was classified by one of six patterns (wall motion score [WMS]: dyskinesis, -1; akinesis, 0; severe hypokinesis, 1; hypokinesis, 2; slight hypokinesis, 3; normal, 4). By echocardiography, the average WMS and ejection fraction were similar between the PD(+) group and the PD(-) group on admission. Those parameters were significantly worse in the PD(+) group than in PD(-) group 1 month after onset. The change in WMS was significantly lower in the PD(+) group than in the PD(-) group. The number of patients and segments with more than two grades of improvement of WMS in the PD(+) group was significantly lower than that in the PD(-) group. Angiographically, left ventricular ejection fraction and WMS of the PD(+) group were significantly lower than those of the PD(-) group 3 months later. PDs were detected significantly less frequently in patients treated with thrombolytic therapy, suggesting that microvascular embolization related to formation of the no-reflow phenomenon.

Aged↗
PubMed2000

High temporal resolution for multislice helical computed tomography.

Multislice helical computed tomography (CT) substantially reduces scanning time. However, the temporal resolution of individual images is still insufficient for imaging rapidly moving organs such as the heart and adjacent pulmonary vessels. It may, in some cases, be worse than with current single-slice helical CT. The purpose of this study is to describe a novel image reconstruction algorithm to improve temporal resolution in multislice helical CT, and to evaluate its performance against existing algorithms. The proposed image reconstruction algorithm uses helical interpolation followed by data weighting based on the acquisition time. The temporal resolution, the longitudinal (z-axis) spatial resolution, the image noise, and the in-plane image artifacts created by a moving phantom were compared with those from the basic multislice helical reconstruction (helical filter interpolation, HFI) algorithm and the basic single-slice helical reconstruction algorithm (180 degrees linear interpolation, 180LI) using computer simulations. Computer simulation results were verified with CT examinations of the heart and lung vasculature using a 0.5 second multislice scanner. The temporal resolution of HFI algorithm varies from 0.28 and 0.86 s, depending on helical pitch. The proposed method improves the resolution to a constant value of 0.29 s, independent of pitch, allowing moving objects to be imaged with reduced blurring or motion artifacts. The spatial (z) resolution was slightly worse than with the HFI algorithm; the image noise was worse than with the HFI algorithm but was comparable to axial (step-and-shoot) CT. The proposed method provided sharp images of the moving objects, portraying the anatomy accurately. The proposed algorithm for multislice helical CT allowed us to obtain CT images with high temporal resolution. It may improve the image quality of clinical cardiac, lung, and vascular CT imaging.

Algorithms↗
PubMed1998

[Diagnosis of the wall-thickened lesions of the gallbladder with dynamic MRI].

We studied 32 patients with the thickened lesions of the wall of the gallbladder by using dynamic MRI. We tried the differential diagnosis of gallbladder lesions according to the time intensity curve (TIC) and enhanced pattern. TIC of carcinoma was elevated more seeply from plain to arterial phase than the inflammatory diseases. The Inflammatory diseases were keeping three-layer structures of the wall of the gallbladder, but gallbladder carcinoma destroys the wall-structure. We could diagnose as direct liver invasion of the carcinoma clearly. We could exactly diagnose adenomyomatosis in dynamic MRI by small low intensity spots within the wall of the gallbladder. In the patients with gall stones, the wall of the gallbladder were more clearly observed in dynamic MRI compared with US and EUS.

Carcinoma, Adenosquamous↗
PubMed1997

Total anomalous pulmonary vein drainage in an adult diagnosed by helical computed tomography.

A 41-year-old man visited our hospital with the complaint of palpitation by atrial flutter. He was finally diagnosed as total anomalous pulmonary vein drainage by helical computed tomography (CT). This case is very unusual due to the lack of symptoms until the age of 41. The absence of pulmonary artery stenosis, and the presence of atrial septal defect providing sufficient right to left shunt flow to maintain the output of left ventricle are some of the reasons to explain the lack of symptoms and very slight impact on daily life. Helical CT, in particular 3-dimensional imaging, is very useful in diagnosing complicated cardiovascular deformation as in this case.

Adult↗
PubMed1996

Guidance with real-time CT fluoroscopy: early clinical experience.

A recently developed real-time computed tomography (CT) fluoroscopy system, which provides effective real-time reconstruction and display of CT images, was used to monitor nonvascular interventional procedures performed in 57 patients. Biopsy of thoracic lesions (n = 38), biopsy or drainage of pelvic lesions (n = 6), drainage or aspiration of intracranial hematomas (n = 9), and other procedures (n = 4) were performed. CT fluoroscopy successfully depicted the entire procedure in all patients. In thoracic lesions, a mean 1.3 passes was necessary to gain access to the lesion. Sufficient cytologic samples were obtained in 32 of 33 pulmonary lesions with a mean diameter of 26 mm.

Adult↗
PubMed1996

Radiation dosimetry at CT fluoroscopy: physician's hand dose and development of needle holders.

The radiation dose to physicians' hands without and with use of needle holders was determined at 10 computed tomography (CT) fluoroscopy-guided transthoracic needle biopsies. As measured with ionization chambers (tube voltage, 80 kVp; tube current, 30 mA), the mean absorbed dose rate without and with holders was 1.14 mGy/sec +/- 0.02 (standard deviation) and 0.019 mGy/sec +/- 0.001, respectively. The mean duration of CT fluoroscopy was 59 seconds in 10 biopsies performed with a holder and 82 seconds in 10 biopsies performed without a holder (difference not statistically significant). The needle holders did not cause any artifacts that interfered with the biopsy procedure.

Biopsy, Needle↗
PubMed1995

[Clinical usefulness of MRI in acute phase of spinal multiple sclerosis--influence of high-dose steroid therapy in acute phase].

Magnetic resonance imaging (MRI) is useful for detecting spinal cord lesions in multiple sclerosis (MS). In this study, we have examined MRI for 14 patients (26 cases) with clinically definite MS and investigated the correlations between neurological and MRI findings before and after high-dose corticosteroid therapy (pulse therapy). High signal intensity areas on T2-weighted images (T2WI) were found in 25 of 26 cases. In 22 cases spinal level of clinically suspected lesions were involved in these high intensity areas. T1-weighted images (T1WI) after intravenous gadolinium with diethylenetriamine pentaacetic acid (Gd-DTPA) were also obtained and in 12 of 17 cases before pulse therapy, the symptoms and enhancement of lesions correlated well. The symptoms regressed in all cases after pulse therapy, and high-intensity areas in T2WI became less distinct. Gd-DTPA enhanced areas disappeared in 6 cases and became smaller in 3 of 12 cases. Additional pulse therapy in 3 cases effectively diminished the enhanced areas in these cases. In one patient who had repeated pulse therapy, MRI showed no enhancement. In two other patients who continued on decreased steroid dose had relapses, pulse therapy was therefore started again, providing a good recovery both clinically and radiologically. The changes of MRI findings and clinical course suggest that the pathological changes in spinal MS may be caused not only by demyelination but also by parenchymal edema. Clinical and MRI concordance was significantly better with Gd-DTPA enhanced T1WI than the high-intensity areas in T2WI. Contrast enhancement gives more information about disease activity and the reaction to therapy.

Acute Disease↗
PubMed1995

[Clinical usefulness of helical-scanning CT for the evaluation of arteriosclerotic carotid lesions].

We examined arteriosclerotic carotid lesions in 76 patients using helical scanning CT (HES-CT), and evaluated the clinical usefulness of this method. A high speed slip-ring X-ray CT system was used. Scanning of the neck was performed for a 30 second period following intravenous bolus injection of non-ionic contrast medium, while couch top movement was 2.0 mm/sec. Multiplannar reconstruction images (MPR-image) and 3-dimensional surface images (3D-image) were reconstructed from the continuous raw data. MPR-images offered axial, coronal and sagittal images in which the lesion could be seen from any direction, and 3D-images that could be freely rotated were obtained by using a track ball and monitor. Eighteen cases were also evaluated by conventional angiography. Excellent HES-CT images were obtained in 73 cases, showing occlusion in 13, stenosis in 34, plaques without calcification in 15 and plaques with calcification in 74 vessels. A good correlation was obtained between HES-CT and angiogram in most cases, and in 6 cases, HES-CT was superior in the detection of stenosis, because it enabled us to observe the lesion from various directions. These results suggested that HES-CT was a minimally invasive, useful diagnostic method for the evaluation of arteriosclerotic carotid disease.

Arteriosclerosis↗
PubMed1994

[Development of real-time CT fluoroscopy].

A new CT system that permits real-time monitoring of CT images was developed. Phantom and volunteer studies revealed that the images were displayed at a rate of six per second with a delay time of 0.83 second with clinically sufficient resolution (256 x 256) using the newly developed fast image processor and partial-reconstruction algorithm. The clinical trial of stereotactic aspiration of intracerebral hematoma was successful. The initial trial with CT fluoroscopy revealed potential usefulness of the system in biopsy and other CT-guided interventions.

Biopsy, Needle↗
PubMed1993

[A case of anaphylactic shock following the administration of Gd-DTPA].

We experienced a case of serious adverse reaction following the administration of Gd-DTPA (gadolinium with diethylenetriamine pentaacetic acid). The patient showed sneezing and hoarseness when Gd-DTPA was administered for the first time. At the second injection, when hydrocortisone was used in advance to prevent allergic reaction, she lapsed into a pre-shock state and anaphylactic reaction was strongly suggested by the laboratory data. The possibility that Gd-DTPA may cause the severe side effects must be noted.

Adult↗
PubMed1993

[An application of dynamic CT for diagnosis of abnormal external ocular muscle movement].

To evaluate the movements of retrobulbar structures radiologically, we have developed a new technique called "external ocular muscle movement CT" (EOM CT), in which dynamic CT scanning is performed while the patient performs controlled eye movements. This new technique was applied in one volunteer and 72 patients with external ophthalmoplegia due to orbital mass lesion, hyperthyroid ophthalmopathy, blowout fracture, and other retrobulbar lesions. EOM CT permits the assessment of extraocular muscle contraction in cases of blowout fracture, the evaluation of muscular contraction in hypertrophy of the extraocular muscles, and the diagnosis of adhesions between the extraocular muscles and intraorbital masses. Radiation dose to the lens from EOM CT was measured using a phantom and TLD, and was compared with that of conventional CT scanning with a 5 mm slice thickness. The dose to the lens from EOM CT was three times higher than that for conventional CT in axial scanning, but in the coronal section of the retrobulbar region, the dose to the lens from EOM CT decreases to one twelfth that of conventional CT. EOM CT promises to be a powerful modality for functional evaluation of the extraocular muscles and other retrobulbar structures.

Adolescent↗
PubMed1993

[Visualization of coronary arteries with helical scanning CT: diastolic reconstruction].

The purpose of this study was the visualization of coronary arteries by the diastolic reconstruction method with helical scanning (HES) CT. We chose diastolic phase images from the image data acquired with the HES technique using a continuous nutate-rotate fast CT scanner, because few motion artifacts are induced by cardiac pulsation during the slow filling diastolic phase. We assessed coronary diseases using this method based on HES-CT, and evaluated its clinical effectiveness. We also studied the clinical value of multiplanar reconstruction and three-dimensional surface reconstruction. The subjects consisted of 31 patients with coronary disease, aged 41-77 years. When a diastolic reconstruction HES-CT was employed, the average rate of visualization of the coronary arteries was 72%. An examination can be completed during a 30-second single breath-hold, permitting the acquisition of coronary artery images with excellent continuity. Calcified coronary arteries can be identified.

Adult↗
PubMed1993

[Clinical usefulness of helical scanning CT (HES-CT) for orbital lesion].

Helical scanning CT (HES-CT) was applied to multiplanar reconstruction (MPR) and 3-D imaging for the diagnosis of 65 patients with orbital lesions. We employed the the Toshiba TCT-900S, a fourth-generation high-speed CT scanner equipped with a slip-ring system. In HES-CT, scanning was performed with continuous rotation of the X-ray tube for 30 s, while the couch top was simultaneously moved at a constant speed of 1 to 2 mm/s. Images were reconstructed from continuous raw data to obtain a slice pitch of 1 mm in the longitudinal direction. HES-CT was found to have some advantages over conventional thin slice CT: 1) a wide area could be scanned in a short time (30 s) without motion artifact, 2) small lesions could be easily detected because slice images could be generated with a fine pitch at arbitrary positions from continuous raw data, 3) MPR images had good continuity in the longitudinal direction, and 4) high contrast of structures was obtained in the orbital region. HES-CT was considered to be useful for the detection of orbital lesions.

Child↗
PubMed1993

[Progress of clinical diagnosis of heart failure].

The role of CT and MRI in the diagnosis of heart failure include evaluation of cardiac function and pathological diagnosis. Recently, both CT and MRI have achieved a marked progress in the time dissolution function. As a result, ultrafast CT and gradient field echo (FE) MRI are now available for evaluation of cardiac function. However, the former is yet to become popular because of its extremely high cost. On the other hand, various methods have been devised for blood flow measurement, which is also possible by MRI. CT and MRI provide useful information for detecting the cause of heart failure. With CT, diagnosis of calcification of pericardium, valves, aorta and coronary artery, that of pericardial effusion retention, congenital heart and great vessel disease, intracardiac tumor and thrombosis, as well as, morphological diagnosis of dissecting aneurysm of aorta are possible. Helical CT provides highly continuous three dimensional information. MRI is also available for morphological diagnosis of congenital heart diseases while it is possible to detect valvular regurgitation and shunt flow with FE method. There is a possibility of elucidating the energy metabolism of phosphoric acid by MR spectroscopy. CT and MRI is considered more useful in the pathological diagnosis of heart failure rather than in the evaluation of cardiac function. Further progress in these fields is expected in the future.

Coronary Circulation↗
PubMed1993

[The administered activity of radionuclides in nuclear medicine--rational reduction of medical radiation exposure].

A survey of 104 hospitals was conducted to determine the administered activity of radionuclides. Eighty-five hospitals responded, and reported a total of 119,614 examinations in one year. The examinations included: bone scintigraphy, 26.4%; Thallium-201 (201Tl) myocardial scintigraphy, 15.5%; Gallium-67 (67Ga) scintigraphy, 13.3%; N-isopropyl-p-[123I]iodoamphetamine (IMP) brain perfusion scintigraphy, 7.0%. The administered activity was corrected by body weight only for children at more than 80% of the responding hospitals. The number of hospitals that reported over-administration of radionuclide varied according to the type of scintigraphy performed: bone, 76%; inflammatory (67Ga), 93%; myocardial (201Tl), 89.2%; brain (IMP), 8.5%. The administered activity of IMP was closer to the upper limits specified in the Recommendations on Standardization of Radionuclide Imaging by the Japan Radioisotope Association (1987), because IMP is very expensive and is supplied as single vials. The highest average effective dose was for myocardial scintigraphy, the second-highest for inflammatory scintigraphy, and the third-highest for bone scintigraphy. In 201Tl and 67Ga scintigraphy, the entire contents of the vial may be administered two days before the expiration date, because the ratio of (true patient administered activity) to (declared patient administered activity) is similar to the ratio of (radioactivity on the day of supply) to (radioactivity on the day of expiration). The factors that influence administered activity are throughput, price of the radionuclide, and whether the radionuclide is sold as a single vial. In order to decrease the effective dose, it is necessary to establish a close cooperation between medical personnel, the makers of radiopharmaceuticals, and manufacturers of gammacameras.

Humans↗