Search

The response of 50 patients who underwent hepatectomy for hepatocellular carcinoma measuring 3 cm or less (at the time of surgery) to transcatheter oily chemoembolization was evaluated. The response was assessed in 5 categories, A: complete necrosis (100%), B: necrosis of at least 95%, C: at least 80%, but less than 95%, D: at least 50% but less than 80%, and E: less than 50% of the tumor cells. Response A was observed in 19 patients (38%), B in 7 (14%), C in 9 (18%), D in 7 (14%), and E in 8 (16%). These results were classified with respect to the histological degree of tumor differentiation, the WHO histological classification, the microscopic patterns of tumor growth, and macroscopic classification. The response was evaluated in relation to the histological grade of tumor differentiation and the WHO histological classification in all categories of response except response A, and there was no significant difference between the categories. The response was obviously better with the expansive type than with the replacing type. Single nodular type lesions were more responsive than the single nodular type lesions with extranodular growth and the contiguous multinodular type. Pretreatment estimation of the microscopic patterns of tumor growth and macroscopic classification appears to be valuable in predicting prognosis.

A water-absorbent particle (a polymer of polyacrylic acid soda) was investigated as a new embolic material. The size of a single particle is 200 microns (N-100) or 10 microns (NP-1010). A particle absorbs 100 times its own weight of physiologic NaCl solution within a few seconds. The particles have no acute or chronic toxicity or immunogenicity. This material suspended by Lipiodol was evaluated in an in vitro study using an AVM model composed of a plastic syringe and polyurethane sponge. The AVM model was perfused by physiological NaCl solution at a pressure of 150 mmHg. The swollen polymer worked as an adequate embolic material in the AVM model, using a minimum quantity. The embolic effect depended upon the quantity and concentration of the suspension. Restoration of flow was not observed within a period of ten minutes. The embolized part was clearly visualized due to the retention of Lipiodol. This material is a promising agent for arterial embolization.

Technetium-99m teboroxime (TEBO) is a new technetium-based myocardial perfusion imaging agent, which has high myocardial extraction and rapid myocardial washout. Its rapid myocardial washout may necessitate rapid imaging protocols. This study was designed to perform exercise/rest SPECT imaging protocols with rapid data acquisition (from 2.8 +/- 1.4 min to 11.2 +/- 4.1 min after injection) in 171 patients with coronary artery disease, 15 patients with cardiomyopathy and 8 patients with other heart disease. The rapid imaging protocols resulted in a high prevalence of good image quality. The diagnostic value of TEBO was recognized from the high concordance of image findings with thallium-201 (201Tl) scintigraphy, 88.2% in the exercise protocol and 89.9% in the rest protocol. Also, the sensitivity and specificity of TEBO for detecting coronary artery disease were comparable (86.6% and 53.9%, respectively) with those of 201Tl (90.7% and 46.2%, respectively). No toxic effects of TEBO were observed in subjective and objective clinical findings and blood examinations. TEBO was finally evaluated to be useful in 98.4% of the patients. Thus, this agent has good clinical potential for myocardial perfusion imaging.

Gd-DTPA enhanced dynamic MR studies were evaluated in six patients with hepatocellular carcinoma associated with portal vein tumor thrombus. The portal vein tumor thrombus was clearly visualized as a low intensity lesion. The hepatic segment supplied by the portal vein showed high intensity, probably due to decreased portal blood flow and compensatory arterial blood flow. Tumors located in this segment were shown as areas of relatively low intensity compared with segmental high intensity areas. Thus dynamic MR study was found to be a useful method for differentiating the tumor from the surrounding nontumorous tissue with decreased portal blood flow.

99mTc-Teboroxime [Chloro[tris(cyclohexyldioxime)methaneboronic acid] (99mTc)technetium], a perfusion agent for myocardial imaging, has a distinct advantage over 201Tl because of its very high myocardial extraction and is a 99mTc compound ideal for gamma camera imaging. This agent also demonstrates rapid myocardial washout, which allows completion of exercise and rest imaging studies in a short interval (to 1 hour). However, the rapid washout necessitates the completion of image acquisition very quickly after injection and therefore may require nonconventional SPECT imaging. In this Phase II study we evaluate the safety and efficacy of 99mTc-Teboroxime to detect coronary artery disease by exercise and rest SPECT imaging in 38 patients with prior myocardial infarction, 31 patients with angina pectoris, and 4 patients with non-coronary cardiac diseases. The 99mTc-Teboroxime dose used was 370-740 MBq in each study. The findings were compared with coronary angiography or 201Tl exercise and redistribution SPECT. No significant adverse reactions or laboratory abnormalities attributable to 99mTc-Teboroxime were observed. The quality of SPECT images was optimal in 62.5% of all patients. The relatively large population of suboptimal cases (37.5%) was attributed to the delay of the start and prolongation of the image acquisition time. In 85.7% of patients whose imaging was started within 5 minutes and completed within 11 minutes after injection, optimal quality was observed. Thus, 99mTc-Teboroxime SPECT requires the rapid completion of image acquisition after injection to achieve optimal image quality. Abnormalities of 99mTc-Teboroxime distribution were detected in 97.1% and 62.1% of patients with prior myocardial infarction or angina pectoris, respectively. The concordance with coronary angiography was 84.4% and 68.0%, and with 201Tl was 78.1% and 74.1%, respectively. Although standardization of the image protocol suitable for this agent is needed for the next study, these high correlations suggest the potential usefulness of 99mTc-Teboroxime SPECT imaging.

Twelve of the patients with advanced (Stage III or IV) hepatocellular carcinoma who received transcatheter chemoembolization survived for more than 5 years. These survivors consisted of 6 Stage III cases and 6 Stage IV cases. Of the 6 Stage III cases, 5 had multiple tumors (larger than 2 cm) in one lobe of the liver, and 1 had tumor invasion into the second portal branch before treatment. Of the 6 Stage IV cases, 4 had had multiple tumors in both lobes, and 2 had had tumor invasion into the main portal branches. Before treatment, 9 of the 12 survivors had been rated as Child's class A. Lipiodol was used in all 12 cases. The results of the present study suggest the usefulness of Lipiodol in treating advanced hepatocellular carcinoma.

To differentiate hepatoma from hemangioma, MR studies were performed for 18 patients with 21 untreated liver tumors (hepatoma 10, hemangioma 11). We obtained inversion recovery snapshot FLASH images of liver tumors with variable TIs (50, 100, 150, 200, 250, 300, 400, and 500 msec). 8 hemangiomas showed higher intensity than liver parenchyma on the images at 150 msec and less of TI, and lower intensity at 200 msec or more TI. In 7, signal intensity of hepatoma became low at 150 msec or less of TI or remained high with prolonged TI. Inversion recovery snapshot FLASH imaging with variable TIs will be useful for differentiating between hepatoma and hemangioma.

Endobronchial intraluminal brachytherapy was conducted for 5 patients with tracheobronchial carcinoma using 192Iridium high dose-rate afterloading machine (microSelectron HDR) and guide tubes of 1.9 mm in outer diameter. Four patients with bronchial non-small cell carcinoma and one with tracheal adenocarcinoma were applied, and a dose of 6 Gy/Fr. at points 1 cm from the source once a week, and a cumulative dose of 18 Gy/3 Fr. was delivered. Guide tubes could be placed up to 3 tubes via the vocal airway, and new computer planning system could afford to calculate dose from independent lining of the source into optimization. This could be done with safety, and no remarkable acute side effects were observed attributable to this method.

An MR study was performed in 73 clinically diagnosed cirrhotic patients to determine correlations among the demonstration of small low intensity nodules (SLINs), secondary changes due to cirrhosis, and serological data. In 32 patients, liver cirrhosis was proved histologically. SLINs were observed in 38 of the 73 patients on gradient echo (GRE) images and in 28 patients on T2-weighted SE images. Patho-MR correlation study of the liver in the 32 histologically proved cirrhotic patients revealed that SLINs were seen on GRE images only in patients with iron deposits in regenerating nodules (RNs). There was no significant correlation between secondary changes due to liver cirrhosis and the demonstration of SLINs. Serological data indicating liver cell injury and iron store in the body were significantly higher in patients with iron deposits in RNs than in those without iron deposits.

In mitral valve disease, it is important to know whether thrombi are present in the left atrium when deciding upon a course of treatment. The left atrial thrombus usually locates in the left atrial appendage. In most cases of mitral valve disease, the left atrial appendage is clearly demonstrated by radionuclide angiography using 99mTc-labeled red blood cells and it can be speculated that the cases in which left atrial appendage are not demonstrated by RNA have left atrial thrombi. On the basis of this hypothesis, the diagnostic accuracy of radionuclide angiography to detect left atrial thrombi was evaluated retrospectively in 60 patients with mitral valve disease who had undergone surgery. The sensitivity of first-pass and equilibrium radionuclide angiography to detect left atrial thrombi was 83% and 67%, the specificity 79% and 54%, and the accuracy 80% and 57%, respectively. Although there were two false-negative cases in which the left atrial thrombi did not locate in the appendage and 10 false-positive cases in which left atrial appendages were not dilated, the negative predictive value was so high that a clearly demonstrated left atrial appendage can be translated into the absence of left atrial thrombi.

When a vasoconstrictor (noradrenaline) was injected during occlusion of the common hepatic artery with a balloon catheter, the vasoconstrictor flowed only into the proper hepatic artery and constricted it. The balloon was immediately deflated and contrast medium injected into the common hepatic artery. The flow of the contrast medium into the gastroduodenal artery was then increased, clearly visualizing the entire pancreatic-duodenal arcade.

Cross sectional echocardiography was used to evaluate the thickness of the ventricular septum in tetralogy of Fallot (TOF). Forty-six patients with TOF and 20 patients with pseudo-truncus arteriosus underwent echocardiography during a five-year period beginning in 1984. Thicknesses of the right ventricular anterior wall (RVAWT), trabecular septum (IVST) and left ventricular posterior wall (LVPWT) were measured in end diastole on parasternal short axis view at the level of the tips of papillary muscles. The ratios of IVST to RVAWT and IVST to LVPWT were assessed. The ratio of IVST to RVAWT was 1.09 +/- 0.15 in the group aged less than 7 years (less than 7 y.o.) and 0.94 +/- 0.15 in the group aged of 7 years or more (greater than = 7 y.o.). The ratios of IVST to LVPWT were 1.10 +/- 0.14 (less than 7 y.o.) and 0.90 +/- 0.15 (greater than = 7 y.o.), respectively. Both ratios were significantly different (p less than 0.01) in the two age groups, and relative thinning of the septum was demonstrated in the older patients. It is speculated that thinning of the interventricular septum is caused by the lower systolic wall stress of the ventricular septum compared with that of the free walls, which is produced under equal systolic pressure of the two ventricles. It is suggested that this thinning is one of the factors that reduces left ventricular function after repair of TOF.

In order to evaluate the efficacy of HCFU as an adjuvant chemotherapy agent for squamous cell carcinoma of the head and neck areas, a randomized comparative study was performed with cooperative facilities. 191 patients who had undergone radical therapy were randomly assigned to the following two groups: Group A was the control group, which underwent radical therapy only, and Group B was a group which received long-term HCFU administration (300-600 mg/day x 12 weeks or more). In the comparison of non-recurrence rate in both groups, Group B had better results among patients who were at the advanced clinical stages such as N1 through N3, Stage II (p = 0.0583) and Stage III (p = 0.0970). The adverse reactions to HCFU included pollakiuria, feverishness, and digestive symptoms, but these were mild and the recovery was possible.

One hundred and sixty-one patients with pulmonary metastases were studied with CT. Six of them proved to have endobronchial (intraluminal) metastatic lesions by bronchoscopy. Retrospective analysis of the CT studies showed obstruction and/or narrowing of the bronchi in 5 cases while no lesion was observed in one patient. Although CT can not always demonstrate intraluminal lesions, it should be performed when an endobronchial metastasis from extrathoracic malignancy is seen by bronchoscopy because it will show hilar or mediastinal lymphadenopathy, or single or multiple pulmonary metastases other than the endobronchial lesion.

We developed a new pulse sequence and investigated whether the anisotropic diffusion in the human brain can be detailed with a standard whole-body MR imager. Apparent diffusion coefficient maps were produced by the proposed sequence using a 1.5-T MR unit. The sequence employed simultaneous application of three orthogonal gradients to achieve an optimal signal attenuation for imaging the brain without any increase in echo time. The orientation of the effective diffusion-encoding gradient was off-axis. On the in vivo apparent diffusion coefficient maps of four healthy volunteers, white matter tracts (the internal capsule and the corpus callosum) and the cortical and deep white matter showed anisotropic diffusion. In the gray matter, such as basal ganglia and thalami, anisotropic diffusion was not observed. A typical whole-body imager can provide in vivo human brain diffusion images of clinical quality. This technique has promising implications for the evaluation of brain development and the diagnosis of degenerative diseases.

T1-weighted MR images of Legg-Calvé-Perthes disease (LCPD) were classified into three groups on the basis of radiographic stage, and morphological differentiation for staging was attempted. In the stage of fragmentation, both enlargement and flattening of the cartilaginous contour surrounding the epiphysis could be recognized on MRI, and the growth plate showed more curvature than normal. This produced flattening of the epiphysis in the shape of a crescent. We confirmed these findings using four indexes for the measurement of cartilaginous outline, and the stage of avascular necrosis and fragmentation could be clearly differentiated. Cartilaginous deformities on MRI are very useful for differentiating between the stage of avascular necrosis and fragmentation.

Chest radiographs in 14 children with foreign bodies in the tracheobronchial trees were evaluated retrospectively. The most common causative materials were nuts, and both main bronchi were most commonly involved. The initial chest radiographs that were used for analysis were obtained one hour to 50 days after aspiration or onset of symptoms. Of the nine cases in which chest radiographs were taken within 7 hours after aspiration, six showed hyperlucency with (three cases) or without overinflation (three cases) in the affected lungs, and the other three showed normal chest radiographs. Two patients had indeterminate diagnoses on chest radiographs at inspiration: one patient underwent chest radiographs at expiration and the other underwent fluoroscopy. Air-trapping was demonstrated in both patients. Of another five cases in which chest radiographs were taken 18 hours after aspiration of a foreign body, three cases showed atelectasis or consolidation and the other two showed hyperlucent lung. From these observations, hyperlucent lung indicates an early stage of the disorder while atelectasis or consolidation indicates a fairly advanced stage. In patients with clinically suspected foreign bodies, we advocate that additional examinations be performed to establish a final diagnosis, even when chest radiographs are normal or indeterminate.

Magnetic resonance (MR) images of 13 patients with osteoradionecrosis of the mandibula were analyzed. Abnormalities were noted in all patients and could be classified into three groups. In nine patients, MR signals were homogeneously low in intensity on both T1 weighted images (T1WI) and T2 weighted images (T2WI), suggesting fibrosis of bone marrow. These nine patients had suffered radiologically and/or clinically overt osteoradionecrosis more than ten months previously, and inflammatory symptoms had settled down by the time of MR study. Two patients showed low signal intensity on T1WI and an area of inhomogeneous high intensity in a diffuse area of low signal intensity on T2WI, suggesting acute inflammation in the irradiated fibrous bone marrow. Both patients suffered pathologic fracture due to osteoradionecrosis and showed severe inflammatory symptoms at the time MR study. In one of the two patients, these pathologic changes were confirmed in surgically excised mandibulectomy specimens. The other two patients showed homogeneous low signal intensity on T1WI and high signal intensity on T2WI, a finding that may be due to slight inflammation. However, in one of the two patients, this signal feature possibly indicated loose fibrosis with marked cellularity.

In patients with subluxation of the patella, injury of the patellar articular cartilage is frequently observed and correct evaluation is important to manage these patients. We examined 11 patients with subluxation of the patella and five normal volunteers. In 12 patellofemoral joints of seven patients with subluxation of the patella, the abnormalities observed on MRI were compared with those on arthroscopy and/or at operation. MRI was performed with a Magnetom 1.5 T (Siemens) using the round surface coil. Pulse sequences were SE (TR 400 ms/TE 19 ms), FLASH (TR 320 ms/TE 15 ms FA 90 degrees and 40 degrees), and SE (TR 2000 ms/TE 26, 70 ms). We analysed MR findings of the 12 abnormal joints and 10 normal joints according to the following classification of abnormalities observed on arthroscopy. (1) normal appearance (n = 3 joints), (2) softening and fibrillation (n = 6), (3) fragmentation (n = 3), and (4) erosion to bone (n = 0). In only one of the six cases with softening and fibrillation observed on arthroscopy, MRI could visualize the thickening of patellar articular cartilage, but in all three cases with fragmentation observed on arthroscopy, MRI could visualize the thin inhomogenous cartilage with irregular surface. The combination of SE (TR 400 ms/TE 19 ms) and FLASH (TR 320 ms/TE 15 ms FA 90 degrees) are extremely effective pulse sequence to detect the abnormalities of patellar articular cartilage. We conclude that MRI is a useful noninvasive method of detecting advanced changes in patellar articular cartilage.

The rewritable and compact media of magneto-optical disk (MOD) is firstly applied to store medical images with spoken reporting. The MOD has multi-media function of communication and filing. Our system is optimized in terms of recording length of speech based upon our clinical research. The results will have influences over the future PACS. One of their examples is possibility of multimedia PACS with images, speeches and demographic data. Another example is prevention of dispersion of images which have no interpretations by radiologists. Our next step is to recognize filed speech in background processing for printing reports.

Dynamic MRI with injection of Gd-DTPA was performed in 7 patients with hepatocellular carcinoma associated with portal vein tumor thrombus. A portal vein tumor thrombus was clearly visualized as a low intense structure. The segment supplied with this portal vein shows high intensity, probably due to the decrease in portal blood flow and compensated arterial blood flow. A tumor itself, located in this segment, was shown as a low intense area. Thus dynamic MRI is a useful method for differentiating the tumor from the surrounding nontumorous tissue with decrease in portal flow.

Real‐time dose monitoring is important to improve the accuracy of prostate permanent implant brachytherapy (PI). However, few data about in vivo dosimetry in PI have been reported because dosimetry of low energy photons from I‐125 sources is challenging. The purpose of this study is to estimate the dosimetric uncertainty in I‐125 permanent implant brachytherapy using 5‐linear array MOSFET. We evaluated the physical characteristics including angular response variability, linearity, calibration factor, and detector response variability for photon beams from I‐125 seed. All experiments were performed using I‐125 seeds to eliminate the energy dependence. Furthermore phantom study was performed to estimate the dosimetric uncertainty in preclinical settings. For isotropic analysis, the response of 270 and 90 degrees were 8 to 15 % lower than 0 degree and in another angle, the differences of responses were within 5%. However, the deviation of each angle was within 6%. The linearity of the readings is excellent (R2=0.098). The fading effect of MOSFET was not observed. Calibration factor was obtained with the standard deviation within 4%. We found that calibration factor was changed by seed‐detector distance (SDD) by 10% in shorter distance (5mm and 7mm) and 4% in greater distance compared with SDD 10mm. The same tendency was observed by Monte Carlo Simulation.Monte Carlo simulation showed that the beam hardening effect occurred as the SDD increased, which can increase additional deviation. In phantom study, treatment planning was performed with 47 seeds in a modified peripheral loading manner. We measured the urethral dose at base, midland, and apex positions during 20 minutes. In mid grand and base regions, measure dose agreed within 6% and in apex region less than 15% differences were observed. These data suggest that in vivo dosimetry in permanent implant brachytherapy with the appropriate correction can be performed within 15%.

Abdominal scintigraphy with intravenous injection of 99mTc-labeled serum albumin was performed in 6 patients with protein-losing enteropathy (PLE) and 3 patients with non-gastrointestinal tract disorders. In 3 out of 6 patients with PLE, abnormal radioactivity was observed in the ileum region 3 hours after injection, and thereafter clear colon image was obtained. In the remaining 3 patients, the colon was visualized 24 hours after injection. On the other hand, in all patients with non-gastrointestinal tract disorders, no abnormal radioactivity was observed in the abdomen until 24 hours after injection. These results indicate that gastrointestinal protein loss could be demonstrated by scintigraphy with intravenously administered 99mTc-labeled serum albumin. In one healthy subject, 99mTc-labeled serum albumin was administered orally and abdominal scintigraphy was performed. Gastrointestinal tract image was only observed and no other image was demonstrated until 24 hours after oral administration. This result suggests that 99mTc excreted into the gastrointestinal tract is not reabsorbed. Therefore, abdominal scintigraphy with 99mTc-labeled serum albumin appears to be a simple and useful method for diagnosis of PLE.

We describe a case of cranial metastasis from an hepatocellular carcinoma studied by computed tomography and cerebral angiography. Although two similar cases have been reported, ours is the first that shows the angiographic findings so clearly and to present with neurological symptoms before primary disease was evident.

We have studied 20 patients with liver tumor (hepatoma 12, hemangioma 6, metastatic tumor 2) using inversion recovery snap shot FLASH dynamic MR imaging. After intravenous injection of Gd-DTPA, serial 17 images were obtained during 7 minutes. Hepatoma showed central enhancement on early phase (0-20 sec) in 11 patients and absent or less enhancement than surrounding liver parenchyma on late phase (1-3 min) in 12 patients. Hemangioma showed peripheral enhancement on early phase in 6 patients, and slight to moderate enhancement on late phase in 5 patients. Peripheral slight enhancement were seen on late and delayed (5-7 min) phase in two patients with metastatic liver tumor. These characteristic enhancement patterns should facilitate differential diagnosis of liver tumors.

Magnetic resonance (MR) imaging of the liver has been useful in detecting hepatic tumors, especially hepatocellular carcinoma (HCC), and in characterizing the internal architecture of HCC. In this paper, we present MR image of the resected cases of HCC with the pathological findings, and assess MR image for the potential utility of demonstrating the pathologic features of HCC treated with TCE.

A randomized, controlled study was conducted to compare the radiographic efficacy, safety and usefulness of ioversol and iopamidol in 146 patients undergoing angiocardiography at six institutions. The hemodynamic and electrocardiographic effects were clinically insignificant and comparable for both agents. Ioversol demonstrated lower incidence of adverse reactions and less heat sensation in left coronary arteriography than those with iopamidol. Overall radiographic efficacy with ioversol was slightly better than with iopamidol, according to the evaluation by both investigators and committee members. Ioversol appears to be very useful for angiocardiography. This comparative study demonstrated the value of safety and efficacy evaluation criteria suggested by the preceding clinical trial with ioversol.

Phantom and volunteer study was performed with spin-echo sequences of different sampling bandwidths to evaluate the narrow bandwidth signal acquisition technique. Our results demonstrated the characteristics of the narrow bandwidth sequence as follows: SNR improvement, sensitive to the field inhomogeneity and motion, loss of edge definition for short T2 tissues, and prominent chemical shift artifacts. Narrow bandwidth sequence with flow compensation was suitable for brain T2 weighted images because of its high SNR and less artifacts. In spite of the improvement of SNR, the narrow bandwidth technique may be inappropriate for short T2 tissues such as muscle, because of prominent chemical shift artifacts and loss of edge definition. Consequently, sampling bandwidth is one of the parameters which can be manipulated to improve MR image quality.

Intrahepatic distribution of the inferior mesenteric blood flow was evaluated with scintigraphy with transrectally administered 123I-iodoamphetamine (IMP). Twelve patients without liver diseases were studied. The IMP image was divided into 3 types; bilateral, left lobar predominant and right lobar predominant. Bilateral, left lobar predominant and right lobar predominant types were observed in 5, 5 and 2 patients respectively. Furthermore, uneven distribution pattern in the left or right lobe was observed in 2 of 5 patients with bilateral lobar type, 4 of 5 patients with left lobar predominant type and 1 of 2 patients with right lobar predominant type. In one patient with left lobar predominant type, repeat examination demonstrated bilateral lobar type. These results suggest that intrahepatic distribution of the inferior mesenteric blood flow is not uniform and consistent.

Regional denervation of adrenergic nerves has been clinically demonstrated in patients with myocardial infarction using I-123 metaiodobenzylguanidine (MIBG) scintigraphy. However, it is not clarified whether adrenergic denervation can be induced by prolonged myocardial ischemia as well as by myocardial infarction. This case with effort angina had 99% stenosis of right coronary artery and showed perfusion defects at inferior myocardial regions in the exercise thallium-201 study. However, inferior wall motion estimated by echocardiography and left ventriculography was normal indicating the absence of myocardial infarction. After percutaneous transluminal coronary angioplasty for the stenosis, I-123 metaiodobenzylguanidine (MIBG) and thallium-201 (Tl-201) myocardial scintigraphies were done to estimate the therapeutic effect of PTCA. Although the Tl-201 study during exercise showed normal findings indicating the success of PTCA, marked defects was detected at inferior myocardial regions in the I-123 MIBG studies just after and 4 hours after an intravenous injection of I-123 MIBG. These results suggest that adrenergic derangement may be induced by prolonged myocardial ischemia and may persist for periods even though myocardial perfusion is normalized.

We have developed a gradient-echo pulse sequence with a short TE less than 4 msec using a data set of asymmetric off-center sampling with a broad bandwidth. The use of such a short TE significantly reduces T2* de-phasing effect even in a two-dimensional mode, and by collecting an off-center echo, motion-induced phase dispersion is also considerably decreased. High immunity of this sequence to these dephasing effects permits clear visualization of anatomical details near the skull base where large local field inhomogeneities and rapid blood flow such as in the internal carotid artery are present.

The development of a new rotating gamma camera SPECT device for imaging the brain was undertaken with the objective of achieving the highest full volume imaging spatial and temporal resolution performance. For this purpose, four rectangular gamma camera detectors were arranged as close to the head as possible, and united in a block to insure detector head registration and alignment as well as to enable rotation stability at high speeds. Phantom and clinical studies performed demonstrated 42 sequential, 4-mm thick transaxial images acquired in one scan and with sufficient volume to permit the entire cerebrum and cerebellum to be imaged with high sensitivity. The central field of view reconstructed spatial resolution measured 7.0 mm full width of half maximum utilizing the high-resolution collimator, and tomographic images of arbitrary planes including sagittal and coronal demonstrated equally high resolution. The high sensitivity and high speed rotational acquisition capability of the device permits dynamic SPECT studies to be carried out in the analysis of rapidly varying radiotracer concentrations.

To detect Adriamycin cardiomyopathy, radionuclide myocardial imagings with Tl-201, Tc-99m pyrophosphate, I-123 metaiodobenzylguanidine and Ga-67 were performed in a 49 year-old-woman receiving Adriamycin (a total dose of 230 mg/m2) for the treatment of breast cancer. This patient demonstrated symptoms of congestive heart failure 2 months after the last intravenous administration. At the period of performing the radionuclide studies, echocardiographic LV ejection fraction (EF) was 22%. Despite severe deterioration of cardiac function, Tl-201 SPECT demonstrated no defect and Tc-99m pyrophosphate (PYP) SPECT demonstrated no positive finding. I-123 metaiodobenzylguanidine (MIBG) scintigraphy demonstrated no regional defect. However, I-123 MIBG washout rate during 4 hours was markedly enhanced, probably reflecting abnormalities of norepinephrine kinetics due to the progression of heart failure. Compared to these pharmaceuticals, Ga-67 was diffusely accumulated in the heart. Then, 5 months after the first study, when LV EF improved to 30% and congestive symptoms disappeared probably owing to beta-blockade therapy, myocardial accumulation of Ga-67 markedly reduced. It has been reported that Ga-67 accumulates in malignant tumor cells and leukocytes. Since, in Adriamycin cardiomyopathy, myocardial accumulation of leukocytes with myocardial fibrotic changes have been histologically demonstrated, the results of Ga-67 scintigraphy may reflect the accumulation of leukocytes. Thus, this case indicates that Ga-67 scintigraphy is advantageous for detecting Adriamycin cardiomyopathy and may be more useful than Tl-201 and Tc-99m PYP scintigraphies.

Myelography and CT myelography (CTM) were reviewed in 18 cases of birth palsy with clinically suspected avulsion injury. Root-somatosensory evoked potential (root-SEP) was also reviewed for myelographic evaluation of the nerve root avulsion in birth palsy. Root-SEP is not induced in case of avulsed nerve roots, but is induced in case of both normal and incompletely avulsed roots. Myelography demonstrated 58 abnormal nerve roots in 18 cases (19 limbs); 45 (78%) complete and 13 (22%) incomplete nerve root avulsions. Each of complete and incomplete avulsions was defined as total absence and partial presence of rootlets on myelography, respectively. Traumatic meningoceles were detected at 46 roots (79%) on myelography and/or CTM; 35 roots on myelography and 45 roots on CTM. CTM could not detect only a very small meningocele at one root. At 11 roots CTM was superior to myelography in delineating a meningocele because CTM is sensitive to a poorly enhanced meningocele. CTM, however, could not diagnose nerve root avulsions so accurately as myelography, since myelography detected 12 (7 completely and 5 incompletely) avulsed roots without meningocele, whereas CTM could not delineate the nerve roots clearly. Thus, myelography is indispensable to evaluate nerve root avulsions without meningocele. Root-SEP was examined in 9 patients who underwent brachial plexus exploration. SEP was negative at 22/25 roots with complete avulsion and was positive at 7/7 roots with myelographically incomplete avulsion, regardless of presence or absence of any traumatic meningocele.(ABSTRACT TRUNCATED AT 250 WORDS)

Portosystemic shunt index was estimated in 7 patients without liver disease and 95 patients with various liver diseases by portal scintigraphy with transrectally administered 123I-iodoamphetamine (IMP). The shunt index was 0% in patients without liver diseases, 5.3% in acute hepatitis, 5.9% in chronic inactive hepatitis, 11.4% in chronic active hepatitis, 56.6% in compensated liver cirrhosis and 88.1% in decompensated liver cirrhosis. The shunt index was significantly higher in liver cirrhosis, especially decompensated stage. In 5 of 9 patients with acute hepatitis, shunt index was 0%. In 3 of remaining 4 patients with elevated shunt index, shunt index became 0% within 1-2 months. Significant relationship was observed between the shunt index and hepatic function tests such as ChE, albumin, gamma-globulin and ICG-R15. These results suggest that the shunt index is independent of hepatic cell necrosis and reveals the shunted blood flow exactly. Therefore, this technique is useful for evaluating the portosystemic shunt in various liver diseases.

The localizing potential of the Mn (III) complex of tetrakis (4-sulfonatophenyl) porphyrin (Mn-TPPS4) for the normal aortic wall was investigated in nine male New Zealand White rabbits by means of 2.0 T magnetic resonance imaging system. Fortyeight hours after intravenous administration of 0.25-0.50 mmol/kg body weight (b.w.) of Mn-TPPS4, the selective contrast enhancing effects in the normal aortic wall were observed using ECG-gated T1 weighted sequence. An intense brownish internal surface was also observed in the post-mortem aorta. These preliminary results indicate that Mn-TPPS4 might be a suitable MRI contrast agent for the localization of the normal aorta. Acute cardio-toxic effects were observed in one animal after 0.25 mmol/kg b.w. of Mn-TPPS4.

A new pulse sequence for in vivo diffusion measurements by magnetic resonance imaging is introduced. The proposed sequence employed gradient sensitization in three orthogonal directions to accentuate the effects of diffusion. The amplitudes and durations of the diffusion encoding gradients were carefully selected to achieve optimal signal-to-noise ratio in diffusion imaging. The pulse sequence was implemented on a superconducting whole body imager operating at 1.5 T. The self-diffusion coefficient of water in a bottle was measured to be 2.17 +/- 0.089 X 10(-9) m2/sec at 23 degrees C consistent with other previous measurements. A preclinical study with a human volunteer was also performed and results were presented.

Epidermolysis bullosa is a group of disorders whose common primary feature is the formation of blisters following trivial trauma. Recessive dystrophic epidermolysis bullosa (RDEB), a subtype of epidermolysis bullosa, is frequently associated with growth retardation. This growth retardation has been reported to be caused by trophopathy following protein loss through skin lesions. Endocrine disorders as the cause of growth retardation in RDEB have not been clearly described. An 11-year-old female had a typical RDEB with dwarfism. Her height was 125 cm and weight was 21 kg, both of which were 2.5 SD below the average. The skin lesions were generalized and probably caused by undernourishment, infection, and blood loss through the skin. However, her serum albumin was at the lower normal limit, and the rapid turnover proteins were slightly decreased. Endocrinological examinations revealed that all the basal levels of pituitary, thyroid, and adrenal hormones were normal. Results of the exercise test, the insulin tolerance test, and the growth hormone-releasing factor test indicated the presence of hypothalamic disorder in secretion of growth hormone. This is the first report of RDEB in which hypothalamic disorder in growth hormone secretion was investigated. On the other hand, growth hormone is known to be involved in collagen metabolism, and a decrease in collagen fibrils and an increase in collagenase activities are found in the skin of RDEB. This implies that this hypothalamic disorder in growth hormone secretion may be involved in the pathophysiology of both dwarfism and the skin lesions in RDEB.

Purpose: We investigated the method to visualize I‐125 seeds in CT‐based postimplant seed identification in prostate permanent implant brachytherapy using CTsinogram. Furthermore, we evaluated the impact of manual seed identification using our method on dosimetric parameter compared with automatic seed identification of commercially available planning system. Method and Materials: The reprojected CTsinogram was used to visualize I‐125 seeds. CTimages of the metal parts only were separated from the original CTimages by setting the threshold for pixel value. Then we performed edge detection. Using these images,sinograms of CTimages with and without seeds were obtained by inverse Radon transform, and the sinogram of the metal image was subtracted from that of the original image. Finally, the image was reconstructed using the sinogram by Radon transform. The phantom study was performed to verify whether our method can separate adjacent seeds correctly. For patient study, postimplant analyses of 10 patients were performed. The implanted seeds were identified both by manually using our method and automatically using Variseed auto seed finder system. The differences of the number of seeds, dose delivered to 90 % of prostate volume (D90), and D5 of urethra between two methods were investigated. For statistics, paired t‐test was performed. Results: In phantom study, even two adjacent seeds were clearly separated by our method but not by automatic seed finder. For patient study, the number and orientation of seeds could be clearly determined. In post implant dosimetry, significant differences were observed between our method and automatic seed finder in seed number (p=0.009) and D90 of prostate (p=0.028). Conclusion: Although our method can only be applicable in manual seed identification, it can be useful in postimplant dosimetry in clinical practice.

Purpose: Postimplant analysis in I‐125 permanent brachytherapy for prostate cancer plays important role in improving the techniques of implant. Although American Brachytherapy Society recommends CT based postimplant analysis, the identification of prostate bundle is quite difficult. In addition, metal artifacts from the I‐125 seeds implanted make it more difficult to identify the prostate. Thus accuracy of the dosimetric parameters associated with volume of prostate such as D90 and V100 may be unclear. The purpose of this study is to mitigate CT metal artifacts due to I‐125 seeds to provide more accurate postimplant analysis. Method and Materials: The prostate phantom that was implanted 3 to 10 seeds per a plane was scanned using 16‐detector raw CT. The sinogram was modified by our algorithm that is similar to projection‐interpolation method to CTimages containing artifacts from I‐125 seeds. The regions of projection data existing I‐125 seeds were identified by observing differences of X‐ray intensity between the phantom and the seeds. Then the regions were interpolated to remove the metal artifacts. The new images were reconstructed with the corrected sinogram. We compared these with the CTimages that are corrected by commercially available metal artifact reduction method. Results: The metal artifacts caused by a small number of I‐125 seeds were completely eliminated by our correcting method. On the other hand, the magnitude of the artifact with the commercially available method was insufficient. With regard to many seeds in the same plane, the metal artifact was mitigated by our method although the contrast of images was degraded. Conclusion: Our method would mitigate metal artifacts caused by I‐125 seeds and be helpful to identify prostate. Although some problems have still remained to improve, our approaches would be adapted to clinical field.

We describe a case of cranial metastasis from an hepatocellular carcinoma studied by computed tomography and cerebral angiography. Although two similar cases have been reported, ours is the first that shows the angiographic findings so clearly and to present with neurological symptoms before primary disease was evident.

Tissue-type plasminogen activator (t-PA) which has a high affinity for fibrin in the clot, was labeled with 131I by the iodogen method, and its binding to de-endothelialized lesions in the rabbit was measured to assess the detectability of thrombi. The de-endothelialized lesion was induced in the abdominal aorta with a Fogarty 4F balloon catheter. Two hours after the de-endothelialization, 131I-labeled t-PA (125 ± 46 μCi) was injected intravenously. The initial half-life of the agent in blood (n = 12) was 2.9 ± 0.4 min. The degree of binding of 131I-labeled t-PA to the de-endothelialized lesion was evaluated at 15 min (n = 6) or at 30 min (n = 6) after injection of the agent. In spite of the retention of the biochemical properties of 131I-labeled t-PA and the presence of fibrin deposition at the de-endothelialized lesion, the binding of t-PA to the lesion was not sufficiently strong. Lesion-to-control ratios (cpm/g/cpm/g) were 1.65 ± 0.40 (at 15 min) and 1.39 ± 1.31 (at 30 min), and lesion-to-blood ratios were 1.39 ± 0.32 (at 15 min) and 1.36 ± 0.23 (at 30 min). These results suggest that radiolabeled t-PA may be inappropriate as a radiopharmaceutical for the scintigraphic detection of a pre-existing thrombotic lesion.

Thirteen patients with radiation necrosis and 6 patients with occlusive radiation-induced cerebrovasculopathy were reviewed. Computed tomography (CT) demonstrated low attenuation with a mass effect and irregular contrast enhancement in the radiation necrosis. The mass effect and the contrast enhancement decreased gradually. Angiography showed an avascular mass, generalized narrowing of the ipsilateral arteries and slow blood circulation in 3 cases. Radiation-induced vasculopathy appeared as localized stenosis and irregular walls of the arteries within the irradiated area. In cases with radiation vasculopathy accompanied by sufficient collateral blood flow brain damage was rarely demonstrated by CT. In patients with radiation-induced vasculopathy the lesion was not associated with signs of radiation necrosis.

Sixteen patients including 13 cases with disk herniation and 3 cases with spondylosis of lumbar spine were examined on a resistive MRI system operating at 0.1 T. All lesions were studied with both multiple spin echo (MSE) and low flip angle gradient echo (LF) techniques to evaluate which technique is more effective in detecting the disk degeneration and the indentation on subarachnoid space. MSE images were obtained with repetition time (TR) of 1100-1500 ms or cardiac gating, an echo time (TE) of 30, 60, 90, 120, 150, and 180 ms symmetrical 6 echoes, and total acquisition time of more than 281 sec. LF images were obtained with TR of 500, 250, and 100 ms, TE of 18 ms, a flip angle of 30 degree, and total acquisition time of 128 sec. Eleven lesions of spinal disk degeneration and 12 of indentation on subarachnoid space were detected with LF. On the other hand, 26 lesions of spinal disk degeneration and 38 of indentation on subarachnoid space were detected with MSE. Although the parameters of LF employed in this study were relatively effective to emphasize T2*-based contrast, the ability of LF in detection of spinal disk degeneration and indentation on subarachnoid space is less than that of MSE. Signal contrast to noise ratios for normal disk and degenerative disk, epidural-fat and disk herniated material, CSF and disk herniated material, and epidural-fat and CSF were less than 4 with LF, but more than 4 with MSE.(ABSTRACT TRUNCATED AT 250 WORDS)