Isamu Narabayashi

Iodine-123 metaiodobenzylguanidine myocardial scintigraphy for prediction of response to β-blocker therapy in patients with dilated cardiomyopathy

This study was performed to evaluate whether iodine-123 metaiodobenzylguanidine (MIBG) myocardial scintigraphy could predict the response to beta-blocker therapy in patients with nonischemic dilated cardiomyopathy (DCM). Beta-Blocker therapy is effective in some patients with DCM. MIBG myocardial scintigraphy has also been suggested to be useful in evaluating the severity of myocardial damage in DCM. However, no data exist on whether MIBG imaging can be used to predict which patients with DCM will respond to beta-blocker therapy. We prospectively evaluated whether MIBG myocardial imaging was useful in predicting responses to beta-blocker therapy in patients with DCM. MIBG imaging was performed in 45 patients with DCM (35 men, 10 women, aged 13 to 68 years) before the start of bisoprolol. The heart to mediastinum (H/M) MIBG uptake ratio was evaluated on initial and delayed images, and the percent washout rate of myocardial MIBG was also obtained from these data. Of the 45 patients, 30 (67%) responded to beta-blocker therapy, whereas 2 were resistant and 13 showed progression of heart failure or died of heart failure. By logistic regression analysis, the H/M uptake ratio on delayed images was seen to be a good predictor of the response to beta-blocker therapy with a threshold of 1.7 (sensitivity = 91%, specificity = 92%, accuracy = 91%, positive and negative predictive value = 97% and 80%, respectively). These results indicate that an H/M ratio > 1.7 on the delayed MIBG myocardial scintigraphic images provides a useful indication of whether patients with DCM will respond to beta-blocker therapy.

Detection and evaluation of pelvic lymph nodes in patients with gynecologic malignancies using body diffusion-weighted magnetic resonance imaging.

Background: In this study, the potential in detecting and evaluating pelvic lymph node metastases on body diffusion-weighted (DW) images was evaluated in patients with gynecologic malignancies. Methods: This study included 18 patients with gynecologic malignancy who underwent magnetic resonance imaging in the pelvis using a 1.5-T superconductive magnet. The identification of pelvic nodes on only T2-weighted (T2W) axial images and on DW axial images in addition to T2W axial images was examined and compared. Moreover, we measured and calculated a short-axis diameter, a long-axis diameter, and a ratio of short- and long-axis diameter of nodes on the T2W images and the apparent diffusion coefficient (ADC) values of the nodes on the DW images. These results were compared with histopathologic results. Results: First, 136 (40%) of 340 dissected nodes were identified on T2W images, and 249 (73%) of 340 dissected nodes were identified on DW images in addition to T2W images. Second, the differences in the short-axis diameter, the long-axis diameter, and the ratio of short- and long-axis diameter on T2W images between metastatic and nonmetastatic nodes were not significant. The differences in the ADC values between metastatic and nonmetastatic nodes were not significant. Conclusions: Body DW images are useful in detection of pelvic lymph nodes in patients with gynecologic malignancy. However, the measurement of ADC values does not contribute to a diagnosis of metastatic nodes.

Body diffusion-weighted MR imaging of uterine endometrial cancer: Is it helpful in the detection of cancer in nonenhanced MR imaging?

OBJECTIVE In this study, the authors discussed the feasibility and value of diffusion-weighted (DW) MR imaging in the detection of uterine endometrial cancer in addition to conventional nonenhanced MR images. METHODS AND MATERIALS DW images of endometrial cancer in 23 patients were examined by using a 1.5-T MR scanner. This study investigated whether or not DW images offer additional incremental value to conventional nonenhanced MR imaging in comparison with histopathological results. Moreover, the apparent diffusion coefficient (ADC) values were measured in the regions of interest within the endometrial cancer and compared with those of normal endometrium and myometrium in 31 volunteers, leiomyoma in 14 patients and adenomyosis in 10 patients. The Wilcoxon rank sum test was used, with a p<0.05 considered statistically significant. RESULTS In 19 of 23 patients, endometrial cancers were detected only on T2-weighted images. In the remaining 4 patients, of whom two had coexisting leiomyoma, no cancer was detected on T2-weighted images. This corresponds to an 83% detection sensitivity for the carcinomas. When DW images and fused DW images/T2-weighted images were used in addition to the T2-weighted images, cancers were identified in 3 of the remaining 4 patients in addition to the 19 patients (overall detection sensitivity of 96%). The mean ADC value of endometrial cancer (n=22) was (0.97+/-0.19)x10(-3)mm(2)/s, which was significantly lower than those of the normal endometrium, myometrium, leiomyoma and adenomyosis (p<0.05). CONCLUSION DW imaging can be helpful in the detection of uterine endometrial cancer in nonenhanced MR imaging.

Preoperative diagnosis of lymph node metastases in gastric cancer by magnetic resonance imaging with ferumoxtran-10.

BackgroundKnowledge regarding the presence and location of lymph node metastasis in gastric cancer is essential in deciding on the operative approach. Lymph node metastases have been diagnosed with imaging tests such as computed tomography (CT) and ultrasonography (US); however, the accuracy of such diagnoses, based on size and shape criteria, has not been adequate. Ferumoxtran-10 (Combidex; Advanced Magnetics) is a lymphotropic contrast agent for magnetic resonance imaging (MRI) whose efficacy for the detection of metastatic lymph nodes in various cancers has been reported by several investigators; however, its efficacy for this purpose has not been reported for gastric cancer. We investigated the efficacy of ferumoxtran-10-enhanced MRI for the diagnosis of metastases to lymph nodes in gastric cancer.MethodsSeventeen consecutive patients who were diagnosed with a nonearly stage of gastric cancer were enrolled in the study. All the patients were examined by MRI (Signa Horizon 1.5 T; GE Medical; T2*-weighted images) before and 24 h after the intravenous administration of ultrasmall particles of superparamagnetic iron oxide — ferumoxtran-10 (2.6 mg Fe/kg of body weight) — and the presence or absence of metastasis was determined from the enhancement patterns. The imaging results were compared with the corresponding histopathological findings following surgery.ResultsOf 781 lymph nodes dissected during surgery, the imaging results of 194 nodes could be correlated with their histopathological findings. Fifty-nine lymph nodes from 11 patients had histopathological metastases. In nonaffected normal lymph nodes, we observed dark signal intensity on MRI caused by the diffuse uptake of the contrast medium by macrophages resident in the lymph nodes, which phagocytose the iron oxide particles of ferumoxtran-10. The number of phagocytic macrophages was decreased in metastatic lymph nodes, and they showed various patterns of decreased uptake of ferumoxtran-10. Three enhancement patterns were observed in lymph nodes: (A) lymph nodes with overall dark signal intensity due to the diffuse uptake of ferumoxtran-10; (B) lymph nodes with partial high signal intensity due to partial uptake; and (C) no blackening of lymph nodes due to no uptake of ferumoxtran-10. Patterns (B) and (C) were defined as metastatic. The sensitivity, specificity, positive predictive value, negative predictive value, and overall predictive accuracy of postcontrast MRI were 100% (59/59), 92.6% (125/135), 85.5% (59/69), 100% (125/125), and 94.8% (184/194), respectively. These parameters for predictive accuracy were much superior to these parameters previously evaluated by CT or US. Nodes in the retroperitoneal and paraaortic regions were more readily identified and diagnosed on the MR images than those in the perigastric region.ConclusionThe present study confirmed that ferumoxtran-10-enhanced MRI is useful in the diagnosis of metastatic lymph nodes and that the use of this modality will be helpful in treatment decision-making for gastric cancer patients.

Dual-Phase 3D CT Angiography During a Single Breath-Hold Using 16-MDCT: Assessment of Vascular Anatomy Before Laparoscopic Gastrectomy

OBJECTIVE In this study, we evaluated the efficacy of dual-phase 3D CT angiography (CTA) during a single breath-hold using 16-MDCT in the assessment of vascular anatomy before laparoscopic gastrectomy. MATERIALS AND METHODS The study involved 20 consecutive patients (10 men, 10 women; mean age, 59 years) scheduled for laparoscopic gastrectomy for the treatment of early gastric cancer. A dual-phase contrast-enhanced CT scan using 16-MDCT was obtained before laparoscopic gastrectomy. After rapid infusion of a nonionic contrast agent, arterial and venous phase scans were obtained serially with an interval of 15 sec during a single breath-hold of 31 sec. Three-dimensional CTA images in the arterial phase (3D CT arteriography) and venous phase (3D CT venography) were individually reconstructed using the volume-rendering technique, and then the images were fused together. We evaluated the detectability of the celiac trunk, left gastric artery (LGA), right gastric artery (RGA), left gastric coronary vein (LCV), Henles gastrocolic trunk, right gastroepiploic vein (RGEV), and accessory right colic vein on 3D CTA to compare with surgical findings. RESULTS In all 20 patients, 3D CT arteriography and venography clearly showed the celiac trunk, LGA, RGA, Henles gastrocolic trunk, RGEV, and accessory right colic vein, which were correctly identified during surgery. The branching pattern of the celiac trunk was classified as Michels type I in 19 patients and Michels type II in one patient. Imaging showed the RGA originating from the proper hepatic artery (PHA) in nine patients; from the gastroduodenal artery (GDA) in seven patients; and from the left hepatic artery (LHA) in four patients. In 12 patients, the LCV joined the portal vein (PV) and in eight, the splenic vein (SV). In all patients, the accessory right colic vein joined the RGEV, and Henles gastrocolic trunk proximal to the joining point flowed to the superior mesenteric vein (SMV). In all 20 patients, the fused image simultaneously showed arteries and veins around the stomach, with no mismatch between the arterial and venous phase images. In 10 patients, the LCV joined the PV after running along the dorsal side of the PHA, common hepatic artery (CHA), or splenic artery (SA). In eight patients, the LCV joined the SV after running along the ventral side of the PHA, CHA, or SA. In two patients, the LCV joined the PV after running along the ventral side of the CHA, which correlated with the surgical findings. Both the sensitivity and positive predictive values of 3D CTA revealed 100% correct identification of the celiac trunk, LGA, RGA, LCV, Henles gastrocolic trunk, RGEV, and accessory right colic vein. CONCLUSION Dual-phase 3D CTA using 16-MDCT clearly revealed individual arteries and veins around the stomach before laparoscopic gastrectomy. The fused image of 3D CT arteriography and venography during a single breath-hold enabled the simultaneous assessment of arteries and veins before laparoscopic gastrectomy.

Preoperative Evaluation of Local Invasion and Metastatic Lymph Nodes of Colorectal Cancer and Mesenteric Vascular Variations Using Multidetector-Row Computed Tomography Before Laparoscopic Surgery

Objective: To evaluate local invasion and lymph nodes metastasis of colorectal cancer and mesenteric vascular variations using multidetector-row computed tomography (MDCT) before laparoscopic colorectal surgery. Methods: Fifty-one patients with colorectal cancer underwent MDCT. The evaluation items were as follows: (1) local invasion; (2) detected lymph nodes evaluated by short-axis diameter, long-axis diameter, short/long axis diameter ratio, and computed tomography (CT) attenuation; and (3) visualization of mesenteric artery and vein by 3-dimensional-CT angiography. Results: First, in the evaluation of local invasion, overall accuracy was 94.1%. Second, the point of 0.8 or greater in short/long-axis diameter ratio was best index for the diagnosis of metastatic lymph nodes. Using this index, the accuracy of the diagnosis per node was 80.5%. Third, 3-dimensional-CT angiography correctly demonstrated variations of the mesenteric artery and vein. Conclusions: The MDCT was effective for evaluation of local invasion and lymph nodes metastasis of colorectal cancer and mesenteric vascular variations before laparoscopic surgery.

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.

Intraarterial infusion chemotherapy with lipioclol-CDDP suspension for hepatocellular carcinoma

AbstractPurpose: 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 mgl/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 µm (average: 11.59 µm). The LCS obtained demonstrated a suspension of 2–12 µm (average 3.69 µm) 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, 73.787c 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.

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.

Tc-99m sestamibi uptake by malignant lymphoma and slow washout

Tc-99m sestamibi has been used to detect primary brain tumors, lung tumors, and breast cancers. The authors report a patient who had superior vena cava (SVC) syndrome and underwent Tc-99m sestamibi and TI-201 SPECT to differentiate the tumor from thrombus in the mediastinum because of an abnormal mass lesion on a contrast enhanced CT scan. An abnormal area of increased Tc-99m sestamibi uptake in the supra azygos area was demonstrated on early and delayed SPECT imaging. The washout of tumor uptake was slow. The removed tumor was confirmed to be malignant lymphoma.