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Objective: In a small pilot study, we assessed whether early-phase dynamic contrast-enhanced MDCT can be used to detect bladder tumors and whether thin reconstruction improves the detection rate., Subjects and Methods: Thirty-six patients (30 with 59 cystoscopy-proven bladder cancers and six with normal bladders) underwent dynamic contrast-enhanced MDCT of the pelvis and abdomen. Images were obtained from the symphysis pubis to the diaphragm 70 seconds after injection of 100 mL of contrast medium. McNemar test was used to compare sensitivity per patient, segment, and tumor and specificity per patient and segment for each of three reconstruction methods: 5-mm sections with no overlap (i.e., 5-mm axial images), 2.5-mm sections with 1.25-mm overlap (i.e., thin-section axial images), and 2.5-mm sections with 1.25-mm overlap and multiplanar reformation (MPR) (i.e., thin-section axial images with MPR)., Results: MDCT with a combination of thin, overlapped sections and MPR depicted all but one of 47 bladder tumors larger than 5 mm but only five of 12 tumors 5 mm or smaller. There were no false-positive findings. Per-tumor sensitivity was significantly better with thin-section images with MPR (90%) and thin-section images alone (86%) than with 5-mm axial images (80%) (p < 0.05). Per-segment sensitivity was significantly better with thin-section images with MPR (95%) and thin-section axial images alone (87%) than with 5-mm axial images (79%) (p < 0.05). Per-patient sensitivity and per-patient and per-segment specificity did not differ with the three methods., Conclusion: Dynamic contrast-enhanced MDCT of the pelvis shows promise for the detection of bladder tumors. Use of thin-section images with MPR and thin-section axial images alone had a significantly better rate of detection of bladder tumors than use of 5-mm axial images.

Purpose: The purpose of this study was to assess acute and delayed adverse reactions to ferumoxides., Materials and Methods: 473 consecutive patients who underwent ferumoxides-enhanced MRI were enrolled in this study. Following non-contrast-enhanced MRI, patients were interviewed about their allergic history, and after ferumoxides-enhanced MRI, they were asked to fill out a questionnaire sheet to record any symptoms within one week., Results: 345 of 473 questionnaires (72.9%) were returned. Fifty-eight of 345 patients (16.8%) showed some adverse reactions considered to be related to ferumoxides: 25 (7.2%) during administration, 25 (7.2%) later on the day of ferumoxides administration, and 17 (4.9%) within one week. Thirty-three patients (9.6%) showed only delayed adverse reactions. Delayed adverse reactions were more frequent in women than in men (p<0.01), and in patients with any allergic history than in those without such history (p<0.05). Acute adverse reactions tended to be more frequent in patients who had some adverse events to any contrast medium than in those with no such history (p=0.069)., Conclusion: By using the questionnaire, the incidence of adverse reactions to ferumoxides (16.8%) was higher than previously reported from Japanese clinical trials.

Background: We aimed to evaluate the efficacy of a breath-hold superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging protocol for the detection of focal hepatic lesions, in comparison with a non-breath-hold SPIO-enhanced imaging protocol and computed tomography during arterioportography (CTAP) plus CT during hepatic arteriography (CTHA)., Methods: Findings of SPIO-enhanced MR imaging and CTAP/CTHA for 24 hepatic metastases in 17 patients and 29 HCCs in 21 patients were analyzed. All patients underwent breath-hold SPIO-enhanced MR imaging (1.5 tesla), breath-hold plus non-breath-hold SPIO-enhanced MR imaging, and CTAP plus CTHA prior to partial hepatectomy or laparoscopic ablation therapy. Histopathology for lesion characterization and intraoperative ultrasound for lesion detection were available for all patient. Breath-hold SPIO-enhanced MR imaging consisted of T2-weighted single-short fast spin echo (FSE), T2-weighted (T2W) FSE, T2*-weighted gradient echo (GRE), and T1-weighted GRE. For the non-breath-hold imaging protocol, respiratory-triggered, fat-suppressed T2W-FSE was added to the breath-hold MR imaging protocol. Double phase CTAP plus CTHA was performed on an angio-CT system. To compare the three imaging protocols, three radiologists performed blind film reading, and all data, on a hepatic segment-to-segment basis, were entered for alternative free-response receiver-operating characteristic (AFROC) analysis., Results: ROC analysis showed that there was no significant difference in the area under the AFROC curve (A1) value for metastases and HCCs among the three protocols; the breath-hold SPIO-enhanced MR imaging protocol, non-breath-hold MR imaging protocol, and CTAP plus CTHA. The breath-hold SPIO-enhanced MR imaging protocol showed a sensitivity, specificity, and accuracy equivalent to the non-breath-hold MR imaging protocol and CTAP plus CTHA., Conclusions: As a preoperative test, SPIO-enhanced MR imaging could have the potential to replace CTAP plus CTHA in a certain clinical setting.

Purpose: To investigate the mechanism of ring enhancement on ferumoxides-enhanced T1-weighted (T1W) gradient echo images in malignant focal hepatic lesions., Materials and Methods: Eighteen patients with hepatocellular carcinoma (HCC) underwent breath-hold T1-, T2-, and T2*-weighted magnetic resonance (MR) images at 1.5-Tesla after ferumoxides administration. The existence of ring enhancement on T1W, and the maximum size of the area showing decreased phagocytic activity on T2W and T2*W, and that of the area showing ring enhancement on T1W were evaluated. The Kupffer cell (KC) density of HCC itself and peritumoral liver parenchyma was assessed with KC stain sections., Results: Ring enhancement was noted in 13 of 18 HCC (72%). Peritumoral KC density was increased in the ring enhancement (+) group as compared with the ring enhancement (-) group. In the ring enhancement (+) group, the tumor size measured on T2W was smaller than that measured on either T1W or T2*W, suggesting a sustained T1 relaxation effect and a decreased T2* relaxation effect in the peritumoral regions., Conclusion: Ring enhancement on superparamagnetic iron oxide (SPIO)-enhanced T1W may correlate with increased KC density and decreased SPIO clustering in KC in peritumoral regions., ((c) 2005 Wiley-Liss, Inc.)

Purpose: To analyze superparamagnetic iron oxide (SPIO)-mediated hepatic signal intensity change in cirrhotic and noncirrhotic liver and to investigate the relationship between pulse sequence effects in SPIO-enhanced magnetic resonance (MR) imaging for hepatic cirrhosis., Materials and Methods: Twelve patients with and 12 patients without cirrhosis underwent T2-weighted fast spin-echo, T2*-weighted gradient-echo (GRE), and T1-weighted GRE MR imaging before and twice (early and late phase) after SPIO administration. To assess the effect of SPIO, postcontrast relative signal-to-noise ratio (SNR) changes were statistically analyzed with repeated measurements analysis of variance for each pulse sequence., Results: No interaction was shown between groups and data time points for any pulse sequence. There was no significant difference in mean hepatic relative SNR change on T2-weighted fast spin-echo images between the cirrhotic group and noncirrhotic group (-38.6% and -40.7%, early phase; -42.2% and -49.6%, late phase, respectively). For GRE images, statistically significant differences in mean hepatic relative SNR change were found between the cirrhotic group and noncirrhotic group (-14.2% and -44.5%, early phase; -28.5% and -56.4%, late phase on T2*-weighted GRE images (P <.001); 31.8% and 12.9%, early phase; 23.8% and 2.2%, late phase on T1-weighted GRE images (P <.05), respectively., Conclusion: Decreased overall phagocytic activity in cirrhotic liver is more likely due to Kupffer cell dysfunction than to Kupffer cell depletion, since magnetic susceptibility effects on T2*-weighted GRE images depend on intracellular SPIO cluster size.

Recently, some radiologists using non-ionic contrast media for angiography have noted the increased tendency of thrombus formation in the injection syringe or angiographic catheter contaminated with blood. In vitro studies by some authors have shown that non-ionic contrast media had only a slight anticoagulative effect as compared with ionic contrast media. But the in vivo studies comparing the anticoagulative effect of both ionic and non-ionic contrast media have not been performed previously. We investigated the effect of non-ionic and ionic contrast media on platelet aggregation in 40 patients undergoing angiography. The in vivo study revealed a negligible influence of both non-ionic and ionic contrast media on systemic platelet aggregation. The dose of contrast media also showed no significant correlation with platelet aggregation. Our study suggests that the data from in vitro experiments cannot be extended to in vivo study as for the relationship between contrast media and their anticoagulant effect.