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In 60 patients with or without renal disease, I131-Hippuran or I131-Diodrast was injected in a dose of 30 to 50μc. and elimination rates of the radioactive compounds from the circulation were measured by means of serial blood sampling and external counting on the body surface. The elimination constant was calculated from the slowly and exponentially declining part of the curve which began about 20 minutes after an injection. When I131-Hippuran was injected, the elimination rate with the external measurement at the head showed the close agreement with that obtained by serial blood sampling. And it had a close correlation with RBF and rough correlations with RPF and 15-minute excretion of PSP test. On the other hand, when I131-Diodrast was administered, the K values obtained in the same way did not indicate such a good correlation with results of those conventional kidney function tests. The elimanation rates of I131-Hippuran obtained by repeated external measurements were observed to show a good reproducibility, and not influenced by varying the dosage within a range from 10 to 80μc.

(1) A simple new recording apparatus for R.I. was deviced and its usefulness was discussed.(2) Using this apparatus, hepatic blood flow was determined in 152 cases by Au198 colloid method.(3) Simultaneous determinations of Au198 disappearance rate constant at periphery (Kp and KH) and accumulation rate constant in the liver (KL) were made in various diseases, such as liver cirrhosis and congestive heart failure etc.(4) Similar examination is also made after rapid blood transfusion or administration of various drugs, including epinephrine, norepinephrine etc.(5) The K value decreased in congestive heart failure and liver cirrhosis. An increase in the K value was observed in accordance with an increased cardiac output.(6) An advantage of this method and its clinical significance were dis-cussed.

Analysis of radioactive colloidal gold uptake rate in the liver, which has a clinical significance as an indicator of liver blood flow, has been performed by the aid of electronic digital computer. It has been demonstrated that after adequate programming of computer well correlated values with manual calculation could be obtained by electronic computer at high speed. Then the inadequacy of the usual measurement time in cases with liver cirrhosis was discussed. It has been shown that the measurement has to be continued up to 90min. or more in these cases. To overcome this disadvantage, especially in severe cases, new analysing process by the skillful aid of computer was proposed. The principal advantages of the application of electronic computer, high speed calculation with relatively high accuracy, were illustrated in the pilot study by telephone communication between R.I. laboratory and Computer Center. The usefulness of this method in clinical medicine was discussed.

A windowless silicon radiation detector and biotelemetry system has been developed and used in the study of the function of organs of free ranging animals. The system consists of an implantable silicon radiation probe, a transmitter package, an FM receiver, and a data handling unit. The intensity of radioisotopes (RI) taken in the organs is measured continuously with an implantable probe with a 5 mm diameter sensitive area. The transmitter package is composed of an RI signal conditioner, and a transmitter. The prototype transmitter package is made of aluminum, and 2 × 6 × 9.5 cm in size. With electronic components included, it weighs 170 gm. The power consumption of the transmitter is about 100 mW, and is furnished from three 5 V mercury batteries. Two of them are used as the detector bias supply. The system was made of discrete electronic components because of their more reliability, lower operating voltage, and lower power consumption. The fundamental characteristics and field performance of the system were carried out using several dogs with the aid of radioisotopes. The application of the system like the study of liver metabolism of dog is discussed.

The value of an appropriate oblique view renal arteriography which we call “tailored oblique,” was illustrated in 2 cases. In the first case, a renal mass on the left side with anterior exophytic growth was found by computerized tomography (CT). In the second case, a tumor on the right side with posterior exophytic growth was detected by CT. Preoperative angiographies were performed. In both cases, the anteroposterior projections were not diagnostic. But in the “tailored oblique” projections both showed definite tumor vessels. Both tumors were resected and proved to be renal cell carcinomas. We believe “tailored oblique” projection provides additional confirmative information on the nature of the tumor.

The magnetic resonance findings of two hepatomas treated by embolization are presented. The T2-weighted spin echo images showed an increase in signal intensity in the tumor after embolization. This phenomenon corresponded to a decrease in tumor density on CT and to necrosis observed histologically. Magnetic resonance also demonstrated gas bubbles as low signal foci within the embolized tumor.

A new method for computer-assisted quantitative analysis of a thallium (Tl)-201 myocardial image ("corrected" circumferential profile method) was described. Since the Tl-201 myocardial image of a normal subject is not homogeneous, an attempt was made to correct for this non-homogeneity. Three groups of subjects were studied, including 10 normal volunteers (group A, mean age of 27.5 years), 14 patients with atypical chest pain and normal coronary arteriogram (group B, mean age of 56.7 years) and 16 patients with first transmural myocardial infarction (group C, mean age of 71.0 years). The myocardial images were acquired at rest at anterior, left anterior oblique (30 degrees and 60 degrees) and left lateral projections. With a scintigram, the left ventricle was outlined and divided into 24 radial segments by radii drawn from the center of the left ventricle. Average radioactivity per pixel in normal subjects was obtained in each segment and normalized to the highest segment (= 100%). The ratio of 100% to the mean of normalized radioactivity in percent in each segment from 10 normal volunteers was calculated and designated as a correction factor for each segment. After the correction of average radioactivity per pixel in each segment using this correction factor and after relating it to the highest radioactive segment, the mean (= 100%) and standard deviation (SD) were calculated and (100-4SD)% was defined as the normal lower limit. In the scintigram of groups B and C, "corrected" circumferential profiles were obtained from the regional radioactivity multiplied by the correction factor, normalized to the highest segment (100%) and compared with the lower normal limit. The ratio (%) of the area of patient's circumferential profile curve below the normal limit to the total area below the normal limit was obtained at each view and the sum of them was called the total "corrected" defect score. Infarct size analyzed by the "corrected" circumferential profile method correlated well with that analyzed by visual interpretation, and was useful in differentiating group C from group B.

Enterogenous cysts are relatively rare causes of spinal cord compression. A case of enterogenous cyst causing compression of spinal cord at C2–3 is presented. Radiological findings, including MRI, are discussed.

Computed tomography (CT) was performed after 65 transcatheter arterial embolizations (TAE) in 50 patients with hepatocellular carcinoma. Nonenhanced high-density areas were seen in the tumors within 3 days in 17/25 cases (though they soon disappeared) and low-density areas within 2 weeks in 62/65. Gas bubbles were seen in these areas within 2 weeks in 60% of embolizations. Within 3 to 6 months after the first TAE, enhanced lesions developed around or inside the low-density areas in 15/22 patients. Complications appearing within 2 weeks included non-enhanced low-density areas in the liver and spleen, gallbladder thickening, swelling of the head of the pancreas, contrast retention in the kidneys and gallbladder, ascites, and pleural effusion.

Seventy-two patients with hepatocellular carcinoma (hepatoma) and 56 with hemangioma were studied with magnetic resonance (MR) imaging at 0.35 or 1.5 T to evaluate the efficacy of T2 values in differential diagnosis. T2 values were calculated with the two-point method. The mean T2 values of hepatoma and hemangioma were 58.9 msec +/- 8.9 and 101.6 msec +/- 25.8 at 0.35 T and 49.1 msec +/- 9.8 and 85.3 msec +/- 21.2 at 1.5 T. The difference in the T2 values for hepatoma and hemangioma was statistically significant (P less than .001) at both 0.35 and 1.5 T. Fifty-three of 56 lesions (94.6%) at 0.35 T and 86 of 102 lesions (84.3%) at 1.5 T were correctly classified when the T2 borderline between hepatoma and hemangioma was set at 80 msec. All misdiagnosed lesions were hemangioma, and all but one were smaller than 2 cm. However, over 90% of lesions smaller than 2 cm were correctly diagnosed when 70 msec at 0.35 T and 60 msec at 1.5 T were used as borderline T2 values. MR imaging with T2 measurement was very useful for differentiating between hepatoma and hemangioma (including small lesions) at 1.5 T as well as at 0.35 T.

The purpose of this study is to evaluate the clinical efficacy of liver SPECT (single photon emission computed tomography). The two examinations were performed in 76 cases with SOL (space occupying lesion) and 58 normal cases. The results of the image reading by the planar image only (PS) and that of the image reading by the combination of PS and SPECT (PS + SPECT) were analyzed by ROC (receiver operating characteristic) analysis. The ROC curves showed that SPECT appears to reduce the number of results which were equivocal by the image reading of PS only. The detectability of SPECT for SOL in the left lobe of liver was less than that of PS without statistical significance. However, the performance of SPECT for SOL in the right lobe of liver was significantly better than that of PS.

Magnetic resonance (MR) imaging of 43 patients with hepatic tumor was performed during suspended respiration using a fast scan spin echo (SE) technique (SE 200/40) with a single excitation. The resulting images were superior in terms of image quality to conventional ones. Due to the lack of soft tissue contrast, 38 patients received Gd-diethylenetriaminepentaacetic acid (DTPA) at 0.05 mmol/kg and serial scanning (CE-MR) was repeated. Twelve of 14 hepatomas showed isointensity or slightly reduced intensity compared with the liver in unenhanced MR. All metastases (nine patients) showed low signal intensity that was statistically significant (p less than 0.001) in differentiating between hepatomas and metastatic liver tumors. With contrast enhanced MR, both hepatomas and metastases showed changes that cannot be further classified until more cases have been examined. In all 12 cavernous hemangioma cases, Gd-DTPA pooling was observed with extremely high contrast, which was a pathognomonic sign. In fact, four cavernous hemangiomas in two patients with a diameter of 1.0 cm were successfully imaged.

The main purpose of this report is to describe our method of MRI tissue characterization studies, which consists of MR imaging of the patient, precision MR imaging of the excised organ, and pathological examination of the organ. We first made small coils to be used with conventional MRI scanners to examine the excised organs. In order to make it easier to understand the effectiveness of our method, three illustrative case reports of abdominal or pelvic tumors were presented as examples of the tissue characterization studies. In conclusion, this method seemed very useful and, in addition, it was found that this small coil technique has several advantages in other applications.

ST-T isointegral analysis of body surface mapping was used in an attempt to localize ischemic areas on exercise tests. In 28 patients with angina pectoris and 10 healthy subjects, body surface potential was recorded with 87 leads, and ST isopotential and ST-T isointegral maps were constructed. In all 10 healthy subjects, the basic pattern of the ST-T isointegral map showed no significant change after exercise. In 23 of 28 patients with angina pectoris (82%), alterations in the ST-T isointegral map after exercise were observed. They were divided into four types (anterior, inferoposterior, lateral, and global) according to the distribution of negative values, which were well correlated with the extent of ischemic area determined by thallium myocardial scintigraphy and coronary angiography. The postexercise ST-T isointegral map was normalized after administration of nitroglycerin in four of five patients. In five patients (18%) who did not show abnormalities on the postexercise ST-T isointegral map, the magnitude of maximal ST depression was significantly smaller than that observed in the other 23 patients with angina pectoris (0.14 vs 0.23 mV on the average, p less than 0.05). It was concluded that the exercise test with ST-T isointegral mapping is a new method for noninvasive detection of location and severity of ischemic regions.

The authors retrospectively evaluated magnetic resonance (MR) images obtained at 1.5 T in 233 patients with portal hypertension and 91 subjects without it and pathologic findings in four resected spleens (one normal). Multiple, tiny (3-8 mm in diameter), low-intensity spots in the spleen were observed in 21 of 233 patients. Among the imaging studies performed in these 21 patients, the spots were seen on five of 14 T1-weighted images, 11 of 20 proton density images, and 12 of 20 T2-weighted images obtained with spin-echo techniques and on 14 of 14 fast-scan images obtained with gradient-echo rephasing. MR images in the 91 subjects did not show such lesions. MR images of the three spleens resected from patients with portal hypertension showed the low-intensity spots, which corresponded to siderotic nodules found at pathologic analysis. Despite limited pathologic confirmation, siderotic nodules (so-called Gamna-Gandy nodules) are considered the most likely cause of multiple low-intensity spots in the spleen.

Fifty-three patients who had hepatic tumors (24 hepatomas, ten metastases, and 19 cavernous hemangiomas) underwent MR imaging using a 0.35-T superconducting imager. The transverse relaxation time (T2) was calculated from a pair of spin echo images (repetition time [TR] of 1600 msec) with echo delay times (TE) of 35 and 70 msec. The computed T2 value was obtained in a fashion similar to that used to obtain CT numbers with region-of-interest cursors. The mean T2 was 59 +/- 9 msec in hepatomas, 64 +/- 15 msec in metastases, and 100 +/- 30 msec in hemangiomas. The difference between the T2 of hemangioma and that of liver malignancies was statistically significant (P less than .001); however, differentiation between hepatoma and metastases was not possible. The T2 was shorter than 80 msec in all 24 hepatomas and in nine of ten metastases, and was longer than 80 msec in 16 of 19 hemangiomas. Forty-nine of 53 cases (92%) were correctly classified when the borderline of T2 between hemangioma and hepatic malignancies was set at 80 msec. MR with T2 calculation was valuable in differentiating between hemangioma and hepatic malignancies.

Marked accumulation in lung and liver of intravenously--injected 99mTc-microaggregated human serum albumin (liver imaging agent) was observed in rats pretreated with the subcutaneous injection of microaggregated or macroaggregated human serum albumin, whereas accumulation of 99mTc-microaggregated human serum albumin was observed only in the liver of rats pretreated with plain human serum albumin or in non-treated control rats. The activity of the intravenously-administered 99mTc-sulfur colloid was concentrated in the liver and spleen only and not in the lung, of rats previously treated with human serum albumin, microaggregated human serum albumin, or macroaggregated human serum albumin. These observations suggest that the specific accumulation of microaggregated human serum albumin in the lung of rats pretreated with aggregated albumin is due to rapid in vivo clumping of injected particles, possibly due to antigen-antibody reaction.

The value of preoperative bone scans in patients with primaly breast and prostate cancer was evaluated prospectively. The methodology and some clinical results were described previously. The clinical efficacy of the bone scan was assessed by using ROC analysis and we obtained the following results. 1) Preoperative bone scan of carcinomas of the breast is effective for patients with clinical stage IIIA, IIIB and IV. It is not so effective for patients with clinical stage I and II, but there is no denying the importance of it, because it provides a base-line scan for comparison to subsequent scans obtained in the postoperative period. 2) Preoperative bone scan of prostate carcinomas is effective, especially for clavicle, the ribs and the cervical spine, when compared with bone X-ray. 3) Bone scan is effective means for patients who were diagnosed uncertainly to have bone metastasis.

The plan radiographs and computed tomography (CT) scans of 12 children with abdominal neuroblastoma were reviewed to evaluate the incidence and shape of calcification in the tumor. Calcifications were detected in 7 cases by plain radiographs and in 10 by CT. Small dotted and thin ring calcifications were better shown by CT. Ring calcification does not appear to be as rare as has been reported. It is emphasized that all ring calcifications in the vicinity of adrenal glands are not benign.

Computed tomographic (CT) and ultrasonographic (US) images of 17 patients with septate cystic lesions in the upper abdomen were reviewed. US was superior to CT in detecting septation and its presence suggested that the ‘cyst’ was neoplastic in nine. CT plays a complementary role in differentiating cystic lesions.

Longitudinal relaxation times (T1) of 20 brain tumors were calculated in vivo using a whole-body magnetic resonance unit with a 0.15-T resistive magnet. Images employing standard inversion recovery pulse sequences with different intervals between the 180 degrees pulse and selective excitation pulses were compared on every point of the 256 X 256 pixel matrix. Tumor, white matter, and gray matter were sampled from each patient from the computed T1 image for T1 measurement. Astrocytomas, neurinomas, and metastatic tumors showed longer T1 values than did meningiomas. Lipomas had the shortest T1s. It is concluded that it is difficult to predict histological types of brain tumors by the measurement of T1 alone because of the wide variation in relaxation times, but measurement of T1 can be helpful in differentiating brain tumors when additional information about the patient's condition is known.

This report describes the magnetic resonance (MR) demonstration of portal vein tumor thrombus (PVTT) in hepatocellular carcinoma (HCC). In two cases of HCC with PVTT diagnosed by angiography, MR demonstrated PVTT as areas of increased MR signal in the portal vein. Our limited experience suggests the potential utility of MR imaging for diagnosis of PVTT.

In 6 patients with spontaneous rupture of hepatocellular carcinoma complicating liver cirrhosis, but with no occlusion of the main portal trunk, transcatheter arterial embolization was performed within 7 days of the rupture. All 6 patients were thought to be inoperable because of shock state or severe hepatic dysfunction. In all 6 patients, the progressive decrease in the hematocrit ceased soon after the embolization. Five patients survived for 31-168 days after the embolization; 1 patient who developed septicemia died 10 days later. We conclude that transcatheter arterial embolization is beneficial as a procedure of first choice for ruptured hepatocellular carcinoma when the portal blood flow is maintained.

Fifteen patients with primary intrahepatic biliary malignancy (cholangiocarcinoma in 13, biliary cystadenocarcinoma in two) were examined by computed tomography (CT). The CT features were classified into three types: (A) a well-defined round cystic mass with internal papillary projections, (B) a localized intrahepatic biliary dilatation without a definite mass lesion, and (C) miscellaneous low-density masses. Intrahepatic biliary dilatation was noted in all cases of Types A and B and half of those of Type C; dilatation of extrahepatic bile ducts occurred in 4/4, 1/3, and 0/8, respectively. CT patterns, such as a well-defined round cystic mass with papillary projections or dilatation of intra- and extrahepatic ducts, give important clues leading to a correct diagnosis of primary intrahepatic biliary malignancy.

Prospective study of bone scintigraphy was performed on 414 patients with breast carcinoma and 88 patients with prostate carcinoma. In 468 of them, confirmative diagnoses of bone, whether metastasis was existent or not, were made after the observations over a year. Finally, the incidences of bone metastasis were 11 percent for breast carcinoma and 54 percent for prostate carcinoma respectively. The efficacy of preoperative bone scintigraphy in breast carcinoma was comparable to that in prostate carcinoma with regard to improvement of predictive probability of bone metastasis: raising up the probability in the positive cases and bringing down in the negative cases.

Monoclonal antibodies were prepared against human chorionic gonadotropin (HCG). One monoclonal antibody recognized a conformational determinant expressed only on native HCG molecule and another monoclonal antibody had the specificity for the epitopes located on the β-subunit of HCG. Monoclonal antibodies reacting with different antigenic determinants on the HCG molecule were used to develop a simplified 2-site sandwich radioimmunoassay in which one monoclonal antibody was immobilized and another labeled with 125 iodine. This assay was highly specific for HCG and there was no cross-reactivity with α,β-subunit of HCG, luteinizing hormone and follicle stimulating hormone.

The authors have been using medical image filing system TOSHIBA TDIS -FILE as a teaching files archiving and viewing at University of Tokyo, Hospital, Department of Radiology. Image display onCRT was proven sufficient for the purpose of education for small groups of students, as well asresidents. However, retrieval time for archived images, man- machine interface, and financialexpenses are not in a satisfactory level yet. The authors also implemented flexible retrieval schemefor diagnostic codes, which has been proven sophisticated. These kinds of software utilities, as well as hardware evolution, are essential for this kind of instruments to be used as potential component ofPACSystem. In our department, PACS project is being carried on. In the system, TOSHIBA AS3160 workstation ( =SUN 3/160) handles all user interfaces including controls of medical image displays, examination data bases, and interface with HIS. 1. SYSTEM OVERVIEW Fig.1 shows an overview of the system that are being developed as a workstation for thePACSystem. Two image displays with CT images are CRT displays of TDIS -FILE. In this chapter

THE RATE OF ACCUMULATION of a substance in any region of the body is directly proportional to the blood flow to the region, provided the substance is completely removed from the blood and is not metabolized during the period of observation. In the present study, we have successfully used this principle to detect alterations in blood supply to various regions of the lung as a result of certain diseases. The studies were made possible by the development of a new radiopharmaceutical, labeled macro-aggregated albumin (MAA), which has been found to be both safe and effective. Materials and Methods In the initial studies radiodine (I 131 ) was employed as a label for the macro-aggregated albumin. Subsequently we have used chromiumlabeled albumin, because radioactive chromium (Cr 51 ) emits a mono-energetic gamma ray (320 kilo electron volts) that is preferable for scintillation scanning. In addition, the absence of beta emission decreases the radiation

Summary By scintiscanning the lung and liver following the injection of 131 I-macroaggre-gated albumin ( 131 I-MAA) into the spleen, the presence and degree of extra- and intrahepatic shunts were studied. On this basis, 13 patients among 15 cirrhotics and 1 patient with liver fibrosis had collateral circulation in the splenoportal system. Three patients with hemolytic anemias, 4 with hepatitis, and 2 with cirrhosis had no shunts. Shunt indices calculated from liver and lung counts in scintigrams ranged from 18 to 90 in patients with cirrhosis of the liver with shunts and below 6 in patients without shunts.The radioactivity accumulation curves were recorded over the liver and lung following MAA injection to detect the presence of intrahepatic shunts. An initial hump of the liver MAA accumulation curve was observed in 7 cirrhotics, suggesting the presence of intrahepatic shunts.The MAA transit time from spleen to liver was almost the same whether or not cirrhosis was present. Spleen to lung time through collateral veins ranged widely.The application of 131 I-MAA was considered to be an easy and useful method for the detection and semiquantitation of intra- and extrahepatic shunts in cirrhosis of the liver.

A new approach to the measurement of pulmonary function was attempted by the use of catheter-type semiconductor radiation detector (CASRAD). When Kr85 dissolved in normal saline solution is injected as a bolus intravenously, the maximum counting rate obtained in a particular bronchus is a reflection of the amount of pulmonary blood flow and the subsequent washout rate, that of ventilatory efficiency of that lobe. From the basic and model experiments, it is concluded that the ratio of Kr85 counting rates in different bronchi measured by CASRAD can be compared as the concentration ratio of Kr85 if these bronchi are similar in size. Three dogs were used for animal experiments. Kr85 solution was injected as a bolus into the right side of the heart and the counting rate was measured in the upper and the lower lobe bronchus where CASRAD was placed respectively. The maximum counting rates were essentially the same in the upper and the lower lobe bronchus for the supine position, while they tended to get higher in the lower lobe for the head-up position. This phenomenon was explained by the increase of perfusion to the dependent zone of the lung due to the gravity. The approximation of the perfusion ratio between the upper and the lower lobe by the ratio of the maximum counting rate was also attempted. When washout rates of Kr85 in the upper and the lower lobe were compared, there was no significant difference between them whether the dogs were placed supine or head-up. As a preliminary study for the clinical application, CASRAD was used for the measurement of ventilatory efficiency, lobar function, and for the bronchospirometry. The clinical applicability was confirmed. The advantages and limitations were discussed comparing CASRAD with the external counting method.

The phagocytic capacity of the reticuloendothelial system (RES) was measured in patients with pneumococcal pneumonia typhoid fever, sandfly fever, and tularemia.

This is the study attempting to clarify quantitatively the regional disturbance of ventilation-perfusion relationships in pulmonary diseases. Measurements were made on 7 normal subjects, 16 cases with pulmonary parenchymal diseases and 4 cases with pulmonary vascular diseases. Perfusion and inhalation scintigrams were taken in sitting position and were divided into 9 horizontal zones in order to know relative values of regional pulmonary blood flow (Q) and alveolar ventilation (VA). Cardiac output and minute alveolar ventilation were also obtained at the same time. Using these data, absolute values of regional VA, Q and VA/Q of 9 zones were analyzed from the base to the apex of both lungs. In 7 normal subjects the average regional VA /Q ratio was 0.64 at the base and increasing 1.35 at the apex. In 20 patients the ratio ranged between 0 and 11.2, and even in the parts of parenchymal disorders the ratio was generally higher than normal since the decrease of regional perfusion was more remarkable than that of regional ventilation. Discussions were made on the usefulness as well as limitations of this scintiscanning method in approaching ventilation-perfusion unevenness topographically and quantitatively.

A catheter-type semiconductor detector and associated electronics system has been developed. The detectors operate at body temperature and are used for in-vivo beta-ray counting in tissue and body cavities during tracer investigations.

(1) A new and clinically useful method with Au198 colloid for the determination of hepatic arterial and portal blood flow by the external counting method is introduced.(2) In 37 cases of control persons, the ratio of hepatic arterial blood flow to hepatic blood flow was 37.6±3.4 per cent and in 24 cases of liver cirrhosis the ratio was 59.8±6.3 per cent. This mean of the ratio of the liver cirrhosis showed a definitely increased value as compared with the controls (P

A case of enormous intrahepatic shunt between the portal vein and the hepatic vein is described. The lesion was successfully treated by embolisation using stainless steel coils on two occasions, after demonstration by percutaneous transhepatic portography (PTP).

We describe an application of simple scintigraphic localization of therapeutic gelatin emboli during and after transcatheter arterial embolization using gelatin particles labeled with technetium 99m. This scintigraphy required an additional 15-30 minutes and can be useful for prevention of serious complications and for early detection of adverse embolisms.