Three different areas of decreased hepatic radioactivity secondary to a hilar mass.
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Aged↗
Biomedical subjects
I Togami
Publications and source records attributed to I Togami.
Experimental study of fast and ultrafast T2-weighted imaging sequences using AMI-25 superparamagnetic iron oxide (SPIO).
The objective of this study was to evaluate fast and ultrafast T2-weighted images (T2WI), including echo planar imaging (EPI), using an AMI-25 agar phantom. Image quality for conventional spin echo (CSE) and turbo spin echo (TSE) was almost equivalent. In high-resolution TSE, image quality was highest due to the use of a 512 x 256 matrix. Half-Fourier single-shot turbo SE (HASTE) was associated with blurring of images, and turbo-gradient SE (TGSE) showed a deterioration of image quality. EPI also suffered from poor image quality because this method is very sensitive to magnetic field inhomogeneity. CSE showed good signal-to-noise ratio (S/N) and contrast ratio (CR), but also required the longest imaging times. Among the TSE sequences, TSE with a short echo train length (ETL) was superior in terms of S/N. The CR of EPI and fast low angle shot (FLASH) images were improved in proportion to the effective echo time (TE). At present, TSE is inferior to CSE in terms of S/N and CR. However, taking into consideration scanning time, TSE with a short ETL is thought to be suitable for routine examinations. Effective TE is an important factor in gradient echo (GRE) examinations.
Contrast Media↗
Nontumorous decrease in Tc-99m GSA accumulation.
Nontutimorous decrease in 99mTc-GSA accumulation has not been well covered in the literature. Understanding of this phenomenon is, however, essential for accurate evaluation of regional hepatic function. Scintigrams (transaxial SPECT) of 269 patients who underwent 99mTc-GSA liver scintigraphy were reviewed for the presence of nontumorous decreases in 99mTc-GSA accumulation. Nontumorous decreases in 99mTc-GSA accumulation were seen in 32 of 269 patients (12%). In 16 of the 32 patients (6%), nontumorous decreases in 99mTc-GSA accumulation corresponded to regional decrease in portal venous flow. The causes of such decrease in portal venous flow were portal thrombus of hepatocellular carcinomas in eight patients, portal venous stenosis or occlusion by hilar cholangiocarcinomas in five patients, inter alia. In eight patients (3%), the regions with decreased 99mTc-GSA accumulation correlated with massive hepatic necrosis in fulminant hepatitis, scar in hepatitis, or confleuent in portal venous flow, lobar biliary stasis, or both. In four patients (1.5%), the exact causes of nontumorous decrease in 99mTc-GSA accumulation could not be determined.
Adult↗
Assessment of secondary necrosis of Jurkat cells using a new microscopic system and double staining method with annexin V and propidium iodide.
Using a new system developed by us for acquiring microscopic images automatically, we compared the morphological changes that apoptotic cells undergo with changes in the staining pattern of annexin V-enhanced green fluorescent protein (AV-EGFP) and propidium iodide (PI) in individual cells. Jurkat cells were treated with 5 mM CaCl2 alone, anti-Fas antibody and heating at 42 degrees C for 30 min or 46 degrees C for 60 min, and then were incubated in medium with 5 mM CaCl2. Time-lapse DNA fragmentation analysis and morphological observation revealed that the anti-Fas antibody and heating at 42 degrees C for 30 min induced typical apoptosis in the cells, and heating at 46 degrees C for 60 min induced typical necrosis. Time-lapse observation of individual cells stained with AV-EGFP and PI confirmed that apoptotic cells were stained at first with AV-EGFP alone, and thereafter also with PI when the cellular membrane ruptured and the cell underwent secondary necrosis. Most of the cells which underwent necrosis were stained simultaneously with AV-EGFP and PI. There was a significant time interval between the staining of individual cells with AV-EGFP, indicating apoptosis, and staining of these cells with PI, which indicated the occurrence of secondary necrosis. These results suggest that time-lapse examinations are necessary to distinguish apoptosis, secondary necrosis and necrosis in cells from one another. This study presents direct evidence that apoptotic cells undergo secondary necrosis, which could be recognized with PI.
Annexin A5↗
Iodine-131 MIBG uptake in hydronephrosis due to compression by a large adrenal mass.
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3-Iodobenzylguanidine↗
A new experimental system for irradiating tumors in mice using a linear accelerator under specific pathogen-free conditions.
We developed a reliable system for the irradiation of xenografted tumors in mice which allows for accurate local irradiation under specific pathogen-free conditions. The system presented here consists of acrylic supports for mice and an acrylic box connected to a pump through 0.22 microns pore-sized filters. Mice with xenotransplanted tumors growing on their right hind legs were set on the supports and put into the box in a laminar flow hood. The tumors of 7 mice were irradiated simultaneously with X-rays of 6 and 10 MV generated by a linear accelerator at a dose rate of 3.1-4.7 Gy/min. The air was ventilated through filters during irradiation in the closed box. Microorganism tests confirmed that no bacteria entered or left the box. One of the significant characteristics of this setup is that it allows for irradiation under conditions of acute hypoxia, which is obtained using an integrated tourniquet. The dose variation among 7 tumors was less than 1%. The rest of the mouse's body was shielded effectively by a half-field technique and a lead block. As a result, the whole body dose for the mice was 0-4% of the total dose absorbed by the tumor. Due to the high dose rate and the ability to irradiate 7 mice simultaneously under specific pathogen-free conditions, this new system can be considered a time-saving and valuable tool for radiation oncology research.
Animals↗
Lobar decrease in 99mTc-GSA accumulation in hilar cholangiocarcinoma.
UNLABELLED: Hilar cholangiocarcinoma can obstruct hepatic ducts and involve the portal veins. Both biliary stasis and decrease in portal venous flow are known to reduce 99mTc-diethylenetriamine pentaacetic acid-galactosyl human serum albumin (GSA) accumulation. The specific relationship between these pathological conditions due to hilar cholangiocarcinomas and 99mTc-GSA accumulation has never been clarified. METHODS: Sixteen patients with hilar cholangiocarcinomas who underwent 99mTc-GSA liver scintigraphy were reviewed. The relationship between significant decrease in 99mTc-GSA accumulation and lobar biliary stasis, or decrease in the portal venous flow, was evaluated. Average counts of region of interest placed in both right and left lobes were compared in the same transaxial SPECT section. Count ratios of right and left lobes were calculated. RESULTS: Significant lobar decrease in 99mTc-GSA accumulation was observed in 6 of the 16 patients. Ipsilateral portal venous stenosis or obstruction was seen in all these 6 patients, whereas ipsilateral portal venous stenosis or obstruction was seen in only 1 of the other 10 patients. Symmetric bile duct dilatation was seen in 13 patients, and asymmetric bile duct dilatation was seen in 3. Lobar decrease in 99mTc-GSA accumulation correlated well with decrease in ipsilateral portal venous flow (P < 0.0005). The count ratio was significantly reduced when unilateral portal venous flow decreased (P < 0.05). CONCLUSION: Using 99mTc-GSA liver scintigraphy, we can predict lobar decrease in ipsilateral portal venous flow and monitor hepatic functional lateralities in patients with hilar cholangiocarcinomas.
Aged↗
[Thymic enlargement exhibiting remarkable respiration-induced changes in form].
The patient was a 30-year-old woman. During an examination for a painful bruise on her back, an anterior mediastinal mass lesion was detected by computed tomographic (CT) scan. A second CT scan 6 days later showed pronounced expansion of the anterior mediastinal mass shadow. A third CT scan performed 18 days later, however, disclosed that the mass had contracted back to the size observed with the initial CT scan. Respiration-induced changes in size were suspected, and breathing dynamic cine magnetic resonance imaging (MRI) was performed. The MRI findings clearly demonstrated that the anterior mediastinal mass shadow contracted on inspiration and expanded on expiration. The patient was admitted for suspected thymoma, and hyperthyroidism was diagnosed. After her thyroid function normalized, a subtotal thyroidectomy and thymectomy were simultaneously performed. The pathologic diagnosis was thymus enlargement and hyperthyroidism, respectively. Breathing dynamic cine MRI provided extremely valuable films that demonstrated remarkable respiration-induced changes in the shape of the enlarged thymus.
Adult↗
Preoperative evaluation of hepatic functional reserve following hepatectomy by technetium-99m galactosyl human serum albumin liver scintigraphy and computed tomography.
It is extremely important to have a good grasp of the acceptable limit of hepatectomy before operation because postoperative liver failure can take a fatal course; however, baseline data on the limit of hepatectomy have not been clearly defined. We therefore evaluated and compared the predicted remnant liver function obtained by computed tomography(CT) and technetium-99m diethylenetriamine penta-acetic acid-galactosyl human serum albumin (99mTc-GSA) liver scintigraphy in order to obtain precise data regarding remnant liver function before hepatectomy. We investigated 20 patients undergoing hepatectomy using the clearance rate of indocyanine green (KICG) as a parameter, and compared the predicted postoperative KICG obtained by CT and by transaxial single-photon emission tomographic (SPET) images acquired by 99mTc GSA liver scintigraphy before hepatectomy. In GSA studies, based on time-activity curves for the heart and liver, we compared HH15 (heart activity at 15 min divided by heart activity at 3 min), LHL15 (liver activity at 15 min divided by heart plus liver activity at 15 min) and KL (obtained from the time-activity curve for the liver) in 103 patients. In 58 patients without increased serum bilirubin, KL was compared with KICG. In four patients, occlusion of the right portal vein was performed with the aim of carrying out secondary hepatectomy, and changes in liver volume were compared between CT and 99mTc GSA liver scintigraphy. The correlation coefficient between the postoperative KICG predicted by CT and the actual postoperative KICG was rather poor, at r = 0.569 (P < 0.05); that between the postoperative KICG predicted by 99mTc GSA liver scintigraphy and the actual postoperative KICG was good, at r = 0.788 (P < 0.01); correlations between KL and HH15 and between KL and LHL15 in 103 patients were very good or good, at r = 0.906 (P < 0.001) and r = 0.807 (P < 0.001), respectively, and that between KL and KICG in 58 patients was very good, at r = 0.916 (P < 0.001). In all four cases of right portal vein occlusion, the remnant liver volume ratio was markedly increased after occlusion in GSA compared with CT, and the postoperative KICG predicted by GSA after occlusion was closer to the actual postoperative KICG than that predicted by CT. It is concluded that 99mTc GSA liver scintigraphy is useful for predicting remnant liver function before hepatectomy and for evaluating changes in regional liver function after occlusion of the portal vein unilaterally.
Aged↗
Bilateral lung volume reduction surgery via median sternotomy for severe pulmonary emphysema.
BACKGROUND: Lung volume reduction surgery either via sternotomy or by thoracoscopy has been demonstrated to be effective for selected emphysema patients in North America and Europe. The present study summarizes short-term results of bilateral lung volume reduction performed via median sternotomy for the first consecutive 39 patients with severe diffuse emphysema in Okayama, Japan, from July 1995 to February 1997. METHODS: There were 35 men and 4 women, and the age range was 54 to 74 years with a mean age of 65 years. All were former heavy smokers and none of them had alpha1-antitrypsin deficiency. Only 9 patients (23%) showed a bilateral upper lobe pattern of emphysema. The operation was done through a median sternotomy, and the most emphysematous portions were excised bilaterally with a linear stapling device fitted with strips of bovine pericardium to prevent air leakage. RESULTS: No operative death was encountered. The first 33 patients completed 3-month follow-up assessment, and their mean forced expiratory volume in 1 second had improved by 41% from 735 mL to 1,037 mL. Other parameters of pulmonary function tests, arterial blood gas analysis, 6-minute walking distance, and dyspnea scale also had improved significantly. These improvements lasted for at least a year. CONCLUSIONS: Bilateral lung volume reduction surgery via median sternotomy is a safe and effective procedure for selected severe emphysema patients. Although the pattern of emphysema might be different between countries, the results in Japanese patients were similar to those previously reported in North American and European patients.
Aged↗
Technetium-99m-DTPA-galactosyl human serum albumin liver scintigraphy evaluation of regional CT/MRI attenuation/signal intensity differences.
UNLABELLED: Regional attenuation/signal intensity differences seen on CT/magnetic resonance imaging can be a clue in detecting regional hepatic blood flow abnormality. Sometimes, however, they can be misinterpreted as a hepatic neoplasm or, in the case of a true neoplasm, they can lead to an overestimation of its size because these regions often have similar attenuation or signal intensity to hepatic neoplasms. We evaluated 99mTc-diethylenetriaminepentaacetic acid-galactosyl human serum albumin (99mTc-DTPA-GSA) liver scintigrams in patients manifesting regional attenuation/signal intensity differences to further analyze the findings. METHODS: Technetium-99m-DTPA-GSA scintigrams of 23 patients with regional attenuation/signal intensity differences in the liver at dynamic contrast-enhanced CT/magnetic resonance imaging were evaluated. The causes of the differences were arterioportal (AP) shunts in seven patients, decreases in the portal venous flow in seven patients, occlusion of right hepatic vein in one patient, confluent hepatic fibrosis in one patient and unknown in seven patients. The accumulation of 99mTc-DTPA-GSA was compared with each known cause of attenuation/signal intensity difference. Count ratios of the regions to normal hepatic parenchyma also were calculated in all cases. RESULTS: In AP shunts, none of seven patients showed any decreased accumulation in the region. Accumulation of 99mTc-DTPA-GSA decreased in six of seven patients who had decreases in portal venous flow; this incidence was significantly higher than that in patients who had AP shunts (p < 0.005). In cases of unknown cause, two of seven patients showed a decrease in accumulation, but the other five showed no such decrease. The one patient with occlusion of the right hepatic vein showed no decrease, but the confluent hepatic fibrosis showed a significant decrease. The count ratio in AP shunts was significantly larger than that of the decrease in the portal venous flow (p < 0.005). CONCLUSION: Technetium-99m-DTPA-GSA accumulation in AP shunts has a different pattern from that found in patients with a decrease in portal venous flow. Therefore, differentiation between AP shunts, which showed no decrease in 99mTc-DTPA-GSA accumulation, and hepatic neoplasms can be made more easily.
Carcinoma, Hepatocellular↗
[Evaluation of the cystic duct and cysticohepatic junction with MR cholangiography: comparison of various techniques and clinical evaluation with respiratory-triggered three-dimensional multislab technique].
The purpose of this study was to evaluate depiction of the cystic duct and cysticohepatic junction by MR cholangiography (MRC). In 10 volunteers, MR cholangiograms were obtained by breath-hold two-dimensional (2D), respiratory-triggered 2D, respiratory-triggered three-dimensional (3D) single slab, and 3D multislab techniques. The images then were compared qualitatively. MRC using the respiratory-triggered 3D multislab techniques was evaluated as better than the other techniques, and was performed in 35 patients. Depiction of the anatomy of the cystic duct and cysticohepatic junction were evaluated. In 8 of 35 patients, MRC images were compared with those obtained by endoscopic retrograde cholangiography (ERC). The cystic duct and cysticohepatic junction were visualized adequately in 93% of volunteers and patients by the respiratory-triggered 3D multislab technique. Anatomic variations in the cystic duct and cysticohepatic junction were evaluated. The frequency of anatomic variations was the same as previously reported. The anatomic evaluations obtained by MRC were correlated closely with those obtained by ERC in 8 patients. In conclusion, MRC with the respiratory-triggered 3D multislab techniques is useful in evaluation of the cystic duct and cysticohepatic junction.
Adult↗
[Anatomic variants of the cystic duct and cysticohepatic junction: diagnosis with MR cholangiography].
The cystic duct are variable in length, course and site of termination. A knowledge of the variable anatomy of the cystic duct and cysticohepatic junction is important in biliary surgery, because failure to recognize anatomic variations may result in a significant ductal injury. Magnetic resonance cholangiography (MRC) is a recently developed technique that demonstrates the biliary tree noninvasively and without injection of contrast material. Anatomic variants of the cystic duct and cysticohepatic junction that may increase the risk of bile duct injury in biliary surgery are frequently identified with MRC. MRC will be a noninvasive and a useful technique in the diagnosis of anatomic variants of the cystic duct and cysticohepatic junction.
Cystic Duct↗
Evaluation of bone marrow iron by magnetic resonance imaging.
Bone marrow iron was estimated by magnetic resonance imaging (MRI) using spin-echo sequences with multiple echoes in 22 patients with varying degrees of tissue storage iron. Levels of bone marrow iron concentration (BMIC) were determined chemically in biopsied specimens concurrently. Concentrations of serum iron, serum ferritin, and transferrin saturation were also measured to evaluate body iron status. Significant correlation was observed between BMIC and T2 relaxation rate (1/T2) (r = 0.77; p < 0.001) in all patients with BMIC levels below 400 micrograms/ml, while BMIC was not correlated with T2 in patients with extremely high BMIC levels. MRI was considered to be inappropriate for quantitation of 1/T2 in patients with extremely high BMIC due to an extreme shortening of T2 relaxation time. These observations suggest that MRI may be a useful and noninvasive method for systemic quantitative determination of bone marrow iron.
Adolescent↗
[Preoperative evaluation for volume reduction surgery of pulmonary emphysema using MRI: usefulness of HASTE (half-Fourier single-shot turbo SE) sequence during deep respiration].
Volume reduction surgery has recently been an important surgical procedure for patients with severe pulmonary emphysema. We compared the sagittal and coronal images taken by the HASTE sequence with those obtained by turbo FLASH during deep breathing and with CT images obtained under deep inspiration. Clear images were obtained from both sequences, without cardiac or respiratory motion artifacts. The emphysematous areas were demonstrated as low signal intensity areas, as in CT images. The ratio of signal intensity in the expiratory phase to that in the inspiratory phase was lower than that of volunteers in the HASTE sequence. The HASTE sequence provides useful information about respiratory movement as well as about changes in the pulmonary parenchyma when used for preoperative examination.
Adult↗
[Dynamic MR and fat suppression imaging of pancreatic carcinoma].
The usefulness of dynamic MR and fat suppression imaging was investigated in 19 patients with pancreatic duct cell carcinoma. In addition to conventional spin echo imaging, dynamic MR and fat suppression imaging were performed. These images were evaluated for the detectability of lesions. The detectability of lesions was classified as good, fair or poor. On T1 weighted images, 26% of cases were evaluated as "good" and 32% as "fair". On dynamic MRI, 69% of cases were evaluated as "good" and 26% of cases as "fair". On pre- and postcontrast fat suppression images, 32% and 28%, respectively, were evaluated as "good", and 47% and 39% as "fair". Neither T2 weighted images nor enhanced T1 weighted images were useful. Direct comparison between dynamic MR and fat suppression images was also done. In 42% of cases, dynamic MR was superior to fat suppression images and in 42%, dynamic MRI was equal to fat suppression. In 16% of cases, fat suppression was superior to dynamic MRI. It was concluded that dynamic MR and fat suppression imaging were more useful than conventional spin echo imaging for the detection of pancreatic carcinoma.
Aged↗
Evaluation of renal function by dynamic MR imaging: effect of water load.
The aim of this study was to investigate the usefulness of magnetic resonance (MR) imaging in the evaluation of renal function, with particular attention to the effects of water load. Ten healthy volunteers underwent dynamic MR imaging after an injection of gadolinium diethylene-triaminepenta-acetic acid (Gd-DTPA) as a contrast agent to evaluate renal function by the following four methods: the positive method [longitudinal relaxation time (T1) shortening is the dominant effect], the negative method [transverse relaxation time (T2) shortening is the dominant effect] and two intermediate methods by switching the Gd-DTPA concentrations used in the positive and negative methods. A prolonged cortical peak time and a reduced medullary peak level were observed by the positive method under a dehydrated condition, suggesting that these variables were slightly influenced by Gd-DTPA concentrated in the medulla. By the negative method, low signals due to T2* (T2* is the effective transverse relaxation time, typically shorter than T2) shortening appeared in the medulla under normal conditions, but these signals were unclear when the subject was under an overhydrated condition. These results indicate that water metabolism, in addition to imaging parameters and Gd-DTPA dose levels, should be considered when renal function is evaluated by dynamic MR imaging. Analysis of both the pattern of MR images and the time-signal intensity curves may be useful in the evaluation of renal function. The results also indicate that the positive method is preferred when the patient is overhydrated as it allows the evaluation of the local renal kinetic function by recording changes in the regional contrast agent levels.
Adult↗
[Percutaneous transhepatic gastrostomy with CT guidance in patients with partial gastrectomy].
Percutaneous transhepatic gastrostomy was performed in two patients, one with partial gastrectomy and Billroth I anastomosis and one with esophageal reconstruction with subtotal stomach, in whom oral feeding was precluded. In both patients, percutaneous gastrostomy with fluoroscopic guidance was impossible since the gastric remnants were small, had a high subcostal position, and were overlain by the transverse colon, lung and left lobe of the liver. The only route available to avoid the overlying bowel and lung was the transhepatic approach. The gastric remnants were punctured with a 22-gauge PTC needle through the left lobe of the liver with CT guidance, and an 8 Fr. Cope-type catheter was fluoroscopically placed in the gastric remnant or the duodenum after tract dilatation over the guide wire. No complications occurred during or after the procedures, and the condition of both patients was greatly improved. Although gastrostomy in patients with partial gastrectomy is thought to be very difficult, percutaneous transhepatic gastrostomy with CT guidance is easy and may be safe since adhesion between the liver and gastric remnant can prevent massive hemorrhage or displacement of the catheters.
Aged↗