Reduction of the total injection volume of contrast material with a short injection duration in 64-detector row CT coronary angiography.

The ability of short injection duration of contrast material to reduce the total injection volume in 64-detector row CT coronary angiography was investigated. 45 patients were divided into three groups: (i) those receiving 0.8 ml kg(-1) of contrast material (350 mgI ml(-1)) injected with a fixed duration of 14 s (Group A; n = 16); (ii) those receiving 0.8 ml kg(-1) of contrast material injected with a fixed duration of 10 s (Group B; n = 15); and (iii) those receiving 0.7 ml kg(-1) of contrast material injected with a fixed duration of 10 s (Group C; n = 14). All patients then received 20 ml of saline. Contrast densities of the ascending aorta and proximal and distal coronary arteries were assessed where vessel diameters were >2.0 mm. The mean enhancement value in the ascending aorta for Group B was significantly higher than that for Groups A and C (p<0.05), whereas there was no significant difference between Groups A and C. All enhancement values in the coronary arteries were higher than 250 Hounsfield units. The mean enhancement value for each coronary artery in Group B was significantly higher than that for Group A (p<0.05), whereas there was no significant difference between Groups A and C. In conclusion, a short injection duration allows a reduction in the total volume of contrast material from 0.8 ml kg(-1) to 0.7 ml kg(-1) while a steady contrast enhancement is maintained in the ascending aorta and coronary arteries.

Diffusion-weighed MR imaging of pancreatic carcinoma.

PURPOSE: The aim of this study was to demonstrate the feasibility of body diffusion-weighted (DW) MR imaging in the evaluation of a pancreatic carcinoma. MATERIAL AND METHODS: In nine normal volunteers and in eight patients with pancreatic carcinoma, DW images were obtained on the axial plane scanning with a multisection spin-echo-type single-shot echo planar sequence with a body coil. Moreover, we measured the apparent diffusion coefficient (ADC) value in a circular region of interest (ROI) within the normal pancreas, pancreatic carcinoma, and tumor-associated chronic pancreatitis. RESULTS: On the DW images, all eight carcinomas were clearly shown as high signal intensity relative to the surrounding tissue. The ADC value (x10(-3) mm(2)/s) in the carcinoma was 1.44 +/- 0.20, which was significantly lower compared to that of normal pancreas (1.90 +/- 0.06) and tumor-associated chronic pancreatitis (2.31 +/- 0.18). CONCLUSION: Diffusion-weighted (DW) images can be helpful in detecting the pancreatic carcinoma and accessing the extent of the tumor.

Usefulness of saline pushing in reduction of contrast material dose in abdominal CT: evaluation of time-density curve for the aorta, portal vein and liver.

The effects of saline pushing after contrast material injection were investigated as well as the possibility for this technique to reduce contrast material doses in liver CT examinations. 52 patients were divided randomly into three groups: 100 ml of contrast material (300 mg I ml(-1)) only (A; n = 19), 100 ml of contrast material pushed with 50 ml of saline solution (B; n = 17), and 85 ml of contrast material pushed with 50 ml of saline solution (C; n = 16). Single-level images were obtained at the level of the main portal vein after the initiation of contrast material injection. There were no significant differences in the mean peak enhancement values (PE) and the mean time to peak enhancement values (TPE) of the aorta between the three groups. The mean PE of the portal vein in group B increased 21 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean PE of the liver in group B increased 7 HU over that in group A (p<0.05), and there was no significant difference between groups A and C. The mean TPE of the portal vein was shorter by 4 s (p<0.05), and that of the liver was shorter by 5 s (p<0.05) in group C compared with those in group A. In conclusion, saline pushing increases the enhancement values of the portal vein and liver, and allows a contrast material dose reduction of 15 ml without decreasing hepatic and vascular enhancement at adequate scan timing.

Effect of saline pushing after contrast material injection in abdominal multidetector computed tomography with the use of different iodine concentrations.

PURPOSE: To investigate whether saline pushing after contrast material improves hepatic vascular and parenchymal enhancement, and to determine whether this technique permits decreased contrast material concentration. MATERIAL AND METHODS: 120 patients who underwent hepatic multidetector computed tomography were divided randomly into four groups (Groups A-D): receiving 100 ml of contrast material (300 mgI/ml) only (A) or with 50 ml of saline solution (B); or 100 ml of contrast material (350 mgI/ml) only (C) or with 50 ml of saline solution (D). Computed tomography (CT) values of the aorta in the arterial phase, the portal vein in the portal venous inflow phase, and the liver in the hepatic phase were measured. Visualization of the hepatic artery and the portal vein by 3D CT angiography was evaluated as well. RESULTS: Although the enhancement values of the aorta were not improved significantly with saline pushing, they continued at a high level to the latter slices with saline pushing. The enhancement value of the portal vein increased significantly and CT portography was improved with saline pushing. The enhancement value of the liver was not improved significantly using saline pushing. In a comparison between groups B and C, the enhancement values of the aorta and portal vein and the visualization of CT arteriography and portography were not statistically different. CONCLUSION: The saline pushing technique can contribute to a decrease in contrast material concentration for 3D CT arteriography and portography.

Virtual CT colectomy by three-dimensional imaging using multidetector-row CT for laparoscopic colorectal surgery.

Laparoscopic colorectal surgery has been attracting attention for its capacity to improve the quality of life (QOL) of patients. However, there are disadvantages to this approach, namely, it is difficult to obtain an image of the entire view of the operative field, and organs and lesions cannot be manipulated directly by the surgeon during surgery. For this reason, it takes a relatively large amount of time to ligate vessel, which can vary between patients. Furthermore, vessels and organs can be damaged during lymph nodes dissection under laparoscopic guidance, leading to heavy bleeding that prevents the surgeon from having access to a good view of the operative field. Then, to assess preoperatively the vascular anatomy, we carried out multiphase, contrast-enhanced examinations using multidetector-row CT (MDCT) on patients with colorectal cancer, and prepared the fused image of 3D images of arteries, veins, the colorectum, organs, and tumor. We called the utilization of 3D imaging virtual CT colectomy, which contributed to rapid and safe manipulation of the origins of the arteries and the veins, as well as lymph nodes dissection, without incurring injury to the involved arteries and veins.

Usefulness of tc-99m MIBI SPECT in predicting multidrug resistance gene expression levels in non-small cell lung cancer--a preliminary report.

In this study we investigated whether Tc-99m hexakis 2-methoxy isobutyl isonitnile (Tc-99m MIBI) single-photon emission computed tomography (SPECT) has a correlation with the multidrug resistance (MDRI) and multidrug resistance-associated protein (MRP1) gene expression levels in non-small cell lung cancer (NSCLC). Fifteen patients with NSCLC were studied. SPECT images were obtained 15 (early) and 120 (delayed) min after injection of Tc-99m MIBI. We chose only one transverse section and set the region of interest over the tumor and out of the body. The mean counts in the tumor on early and delayed images were corrected by using those in the background and represented as Te and Td, respectively. Resected tumor specimens were frozen with liquid nitrogen and each positive control cell line was cultured. After the total ribonucleic acid (RNA) was extracted from specimens and cell lines, the complimentary deoxyribonucleic acid (cDNA) was amplified by the reverse transcription-polymerase chain reaction (RT-PCR) method. Each product was electrophoresed and fluorointensity was measured. The gene expression level was represented as the ratio of that of the positive control cell line. Te and Td indicated a significant correlation with the MDR1 gene expression level (p = 0.015 and p = 0.022), but not the gene of MRP1 (p = 0.100 and p = 0.145). In conclusion, Te and Td are useful parameters in predicting the MDRI gene expression level, but not MRPI in NSCLC.

[Three-dimensional CT angiography of the hepatic artery with multislice CT: differences in image quality according to scanning pitch].

Three-dimensional CT angiography was reconstructed from the hepatic artery using multislice CT, and the effect of pitch during scanning on the quality of obtained images was examined. We randomly divided patients into two groups, with images of one group scanned at helical pitch 3 and images of the other at helical pitch 5.5. CT angiography was reconstructed by a volume-rendering technique. Evaluation was done visually, taking the sharpness of images of branches of the hepatic artery as a measure. Three-dimensional imaging scanned at pitch 3 tended to be better than that scanned at pitch 5.5.

Utility of Tc-99m GSA whole-body scintigraphy in detecting bone metastases from hepatocellular carcinoma.

Recent advances in the treatment of hepatocellular carcinoma (HCC) have prolonged patient survival. However, the number of patients with bone metastases identified during follow-up examinations has increased. Tc-99m Sn-N-pyridoxy-5-methyltryptophan (Tc-99m PMT) has been reported to accumulate at a high rate in HCC lesions and bone metastases. In the patient described here, whole-body scintigraphy showed accumulation of DTPA galactosyl human serum albumin (Tc-99m GSA) and Tc-99m PMT in bone metastases from HCC. The authors suggest that asialoglycoprotein receptors may be present in bone metastases from well-differentiated HCC. Tc-99m GSA whole-body imaging can be used to detect bone metastases from HCC and to evaluate hepatic reserve.

Multifocal primary lymphoma of bone: scintigraphy and MR findings before and after treatment.

A case of multifocal primary lymphoma of bone is reviewed. Ga-67 citrate, Tc-99m HMDP, and Tl-201 scintigraphs all showed multifocal radiotracer accumulation. CT showed subtle osteolytic and osteosclerotic changes with surrounding soft tissue density mass. MRI clearly showed abnormal signal intensity in the bone marrow. After systemic chemotherapy and infield radiotherapy, the patient showed clinically complete remission. MRI showed reduction of the extraosseous components, but there was little signal change in the bone marrow despite the clinical response to the therapy. Scintigrams were more useful than MRI and CT for both staging and assessing the early response to therapy. The soluble interleukin-2 receptor level was found to be related to tumor cell activity.

Tc-99m PMT whole-body scintigraphy for evaluated of therapeutic effect and for monitoring bone metastasis in a patient with hepatocellular carcinoma.

Detection of metastatic lesions by bone scintigraphy is highly sensitive but has a low rate of specificity. Often bone metastases from hepatocellular carcinoma are not detected by bone scintigraphy because of low uptake or a photopenic area in the tumor. In contrast, Tc-99m Sn-N-pyridoxy-5-methyltryptophan (Tc-99m PMT) whole-body scintigraphy reflects tumor viability, and the specificity of detection is so high that tumor structure can be shown well. Tc-99m PMT whole-body scintigraphy was helpful for evaluating the response to therapy and monitoring the course of the patient described here with bone metastasis from hepatocellular carcinoma.

Stereoscopic display of a three-dimensional image of the larynx using high-speed helical scanning.

To evaluate the usefulness of stereoscopic images of larynges using helical CT in stereo mode, a retrospective review of the characteristics of stereoscopic viewing of larynges was made. The subjects were 3 patients with laryngeal cancer, 1 patient with laryngeal leiomyosarcoma and 1 patient with an advanced tongue carcinoma whose formalin-fixed larynx was extirpated. The larynges were scanned by high-speed helical CT using 1- to 2-mm slices. The reproduction of stereographic images was performed by the manipulation and rotation of three-dimensional structures around the y-axis on the computer display. The three-dimensional images of the complex structures, such as the arytenoid cartilage, aryepiglottic fold and pyriform sinus, were better observed by binocular images (stereograms) than by monocular images. Stereoscopic views of the larynx are useful in producing three-dimensional images of the unseen inner surface of the human body.

Three-dimensional magnetic resonance angiography of vascular lesions in children.

We applied three-dimensional (3D) magnetic resonance (MR) angiography to vascular lesions in children and evaluated the clinical usefulness of this technique. Ten patients, whose ages ranged from 1 month to 16 years, underwent 3D MR angiography for 12 vascular lesions, including lesions in seven pulmonary arteries, two thoracic aortae, a pair of renal arteries, and one iliac artery. Three-dimensional MR angiography was performed with body-or pelvic-phased array coils on a 1.5-T scanner using fast spoiled gradient echo sequence. Data were acquired with the following parameters: TE, 1.9 ms; TR, 10.1 ms; flip angle, 20-60 degrees ; 1 or 2 NEX; field of view, 24-48 x 18-40 cm; matrix, 256 or 512 x 128 or 256; slice thickness, 1.2-7.5 mm; and 12, 28, or 60 partitions. Vascular imaging was enhanced with 20% gadolinium-diethylenetriaminepentaacetic acid. The examination was performed under breath-holding in six patients and with shallow breathing in four patients. In a comparative study with other noninvasive methods, 3D MR angiography was superior in seven of nine cases to other noninvasive examinations and in two cases, all methods evaluated the lesions. Furthermore, six cases were compared with conventional angiography. In five of the six cases, both methods depicted the lesions similarly, and in one case, MR angiography was more effective. A quantitative comparison of vascular diameter in the MR image was made with that in the conventional angiographic image. The correlation between them was excellent: y = 1.145x-2.090 (r = 0.987; P < 0.0001), where x is the diameter in the conventional angiographic images, y is the diameter in the MR images, and r is the correlation coefficient. In conclusion, 3D MR angiography is useful for depicting peripheral vascular lesions in children.

Serial changes in N-isopropyl-p[125I]-iodoamphetamine in mouse lung observed with a confocal laser scanning microscope.

Serial changes in N-isopropyl-p[125I]-iodoamphetamine (125I-IMP) in mouse lungs were observed with a confocal laser scanning microscope. Male mice were intravenously injected with 125I-IMP and subjected to autoradiographic procedures 20 minutes, and 3 and 24 hours after injection. Differential interference contrast (DIC) images and confocal images were obtained with a confocal laser scanning microscope, and superimposed images were evaluated. Large numbers of silver grains were observed in the interstitium, bronchioles, and alveolar sacs 20 minutes after the injection, and lamellar distribution of the grains was observed on the ciliary surface. The numbers of silver grains in the interstitium and bronchioles had decreased 3 hours after the injection of 125I-IMP, but the numbers of silver grains in the alveolar spaces had not. Although small numbers of silver grains remained in both the bronchioles and alveolar sacs 24 hours after the injection, most of them had washed out. Confocal laser scanning microscopy is considered to be a useful procedure for studying the distribution of radioisotopes by microautoradiography, because it allows clear autoradiographs to be obtained in which tissues and silver grains are perfectly matched and all silver grains are in focus.

Abdominal helical CT: evaluation of optimal doses of intravenous contrast material--a prospective randomized study.

PURPOSE: To determine the optimal dose of intravenous contrast material for helical computed tomography (CT) of the abdomen on the basis of patient weight. MATERIALS AND METHODS: A prospective randomized study of helical CT of the abdomen was performed by using different doses of intravenous contrast material in 221 patients (mean body weight, 57.3 kg) who were assigned randomly to three groups receiving 1.5, 2.0, or 2.5 mL/kg or a fixed dose of 100 mL of iopamidol 300. The degree of enhancement was scored visually. The CT numbers (HU) of the aorta, portal vein, liver, and pancreas were obtained at three levels of the abdomen. RESULTS: In arterial enhancement, the 2.0 mL/kg, 2.5 mL/kg, and fixed-dose groups were significantly better than the 1.5 mL/kg group, but there was no significant difference among the 2.0 mL/kg, 2.5 mL/kg, or fixed-dose groups. The degree of enhancement of the liver, pancreas, and portal vein increased with larger doses. At visual analysis, hepatic parenchymal enhancement was graded as good or excellent in 64% of the 1.5 mL/kg, 85% of the 2.0 mL/kg, 94% of the 2.5 mL/kg, and 65% of the fixed-dose groups. CONCLUSION: When dose was tailored to patient weight, the use of 2.0-2.5 mL/kg of intravenous contrast material produced better results than did 1.5 mL/kg or a fixed dose. Arterial enhancement did not differ among the 2.0 mL/kg, 2.5 mL/kg, or fixed-dose groups.

Microsatellite instability and k-ras, p53 mutations in thyroid lymphoma.

Patho-epidemiological studies showed that thyroid lymphoma (TL) arises in inflammatory lesions of chronic lymphocytic thyroiditis (CLTH). Replication error (RER) is found in inflammatory lesions and associated cancer, suggesting that chronic inflammation could be a risk factor for neoplastic development through causing RER. To clarify whether RER is involved in the pathogenesis of TL, we examined the microsatellite instability (MSI) in 9 cases with CLTH and 19 with TL, including 10 diffuse large B-cell lymphoma (DLBL), 4 follicle center cell lymphoma, 3 marginal zone B-cell lymphoma of extranodal (MALT) type, and 2 lymphoplasmacytic type. Sixteen distinct microsatellite repeats were analyzed. Mutations of p53 and k-ras genes were also examined. When alterations at 2 or more microsatellite loci were judged as positive, only 5 DLBL cases exhibited MSI. The frequency of MSI in DLBL was significantly higher than that in other types of TL and CLTH (P < 0.05). Four of 19 cases (21.1%) showed point mutation of the k-ras gene. The k-ras mutations occurred in the cases with DLBL with RER, and four of five cases with RER had a k-ras mutation, indicating a close association between RER and k-ras mutation. p53 mutations were not found in the CLTH. Two of 19 TL cases showed mutations of p53 gene. There was no significant association between RER and p53 mutation. These findings indicate that genomic instability contributes to the progression of TL from low grade to high grade, but not to the development of low grade lymphoma in CLTH lesions.

A case of local recurrent pheochromocytoma: usefulness of I-123 MIBG early SPECT and maximum intensity projection images.

It has been reported that 10% of patients with pheochromocytoma experience recurrence despite surgery. The authors administered I-123 MIBG to patients with recurrent pheochromocytoma and found that early images are more useful than delayed images to detect recurrence. Early imaging with I-123 MIBG is useful for postoperative follow-up studies in patients with pheochromocytoma and those with possible tumor recurrence.

Intraarterial infusion chemotherapy with lipiodol-CDDP suspension for hepatocellular carcinoma.

PURPOSE: To quantitatively evaluate the usefulness of lipiodol-CDDP suspension (LCS) chemotherapy in hepatocellular carcinoma (HCC). METHODS: CDDP (cis-diamminedichloroplatinum) powder was prepared by removing the water and NaCl from aqueous CDDP. Two quantities of prepared CDDP powder, 10 mg and 20 mg, were mixed with 1 ml each of iopamidol 300 mgI/ml (IP300) and lipiodol (LPD) using a high pressure pumping method, thus producing LCS. Thirty-two patients with HCC, who had good renal function [creatinine clearance (Ccr) 50 ml/min or more], received additional intraarterial infusion chemotherapy with LCS or LCS alone. RESULTS: The most frequently observed CDDP powder sizes were 5.95-10.90 microm (average: 11.59 microm). The LCS obtained demonstrated a suspension of 2-12 microm (average 3.69 microm) immediately after mixing, and no significant changes were observed in LCS particle sizes 3 hr after mixing. Moreover, the sustained release with LCS was observed for up to 3 hr. Meanwhile, the peripheral free platinum concentration between intraarterial infusion chemotherapy with LCS and intraarterial infusion with the aqueous solution of CDDP, with respect to variance residence time (VRT), showed a significant difference, with a p value of 0.0382. The survival rate was 89.84% at 1 year, 73.78% at 2 years, and 68.51% at 3 years. Furthermore, the platinum concentration in the tumor was 25-95 times the concentration in the surrounding liver parenchyma. CONCLUSION: Good clinical results can be expected by applying LCS to HCC.

Technetium-99m MIBI single photon emission computed tomography as an indicator of prognosis for patients with lung cancer-preliminaly report.

PURPOSE: We performed technetium-99m hexakis-2-methoxyisobutylisonitrile (Tc-99m MIBI) single photon emission computed tomography (SPECT) in 23 patients with primary lung cancer between July 1993 and March 1996. We evaluated the relationships among the uptake ratio, retention index and the prognosis after radiation therapy and/or chemotherapy. MATERIALS AND METHODS: Tc-99m MIBI SPECT was performed at 30 minutes and at 3 hours after intravenous injection of 600 MBq of Tc-99m MIBI with three gamma camera detectors (GCA-9300A/HG) on transverse SPECT images. Regions of interest were set in the area of abnormal uptake of Tc-99m MIBI and in the contralateral normal lung. The ratio of uptake in the lesion to that in the contralateral normal lung was obtained on early images (early ratio; ER) as well as delayed images (delayed ratio: DR). The retention index (RI) was calculated as follows: RI = (DR - ER)/ER x 100. The ratio was compared with survival time and prognostic factors. RESULTS: There was no correlation between ER and DR. The patients with high RI survived longer than those with low RI (median survival, 19.4 months vs. 9.4 months; p = 0.0104 by the Mantel-Cox test). CONCLUSION: These results suggest that RI is the most useful among Tc-99m MIBI indices of primary lung cancer in predicting prognosis.

Helical CT of the liver with computer-assisted bolus-tracking technology: scan delay of arterial phase scanning and effect of flow rates.

PURPOSE: The purpose of this work was to assess the scan delay and the effect of flow rates on arterial phase scanning of hepatic CT. METHOD: One hundred twenty patients suspected of having hepatocellular carcinoma were examined by three-phase helical CT using computer-assisted bolus-tracking technology. We set the region of interest (ROI) in the abdominal aorta at the level of the celiac artery as a baseline. The triggering threshold was set at 100 HU. A volume of 100 ml of iomeprol (350 mg of I/ml) was administered at 2, 2.5, or 3 ml/s i.v. RESULTS: In all cases, helical CT scanning began after reaching the ROI threshold. Then, portal venous phase scanning was initiated 50 s after arterial phase initiation. The mean delay time from the initiation of contrast agent administration to the beginning of arterial phase scanning was 29.2 +/- 3.8 s (mean +/- SD, range 22-39 s). A faster injection rate significantly shortened the scan delay (p < 0.01). In portal venous phase scanning, calculated areas under the hepatic enhancement curves were almost equal among different injection rates. CONCLUSION: The computer-assisted bolus-tracking technology is a useful method for determining an individual scan delay of arterial phase CT.