| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Gastrointestinal Imaging |
1 From the Department of Radiology, Rinku General Medical Center, 2-23 Rinkuorai-kita, Izumisano City, Osaka 598-8577, Japan. Received July 12, 2001; revision requested August 5; final revision received March 18, 2002; accepted March 26. Address correspondence to K.A.
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
MATERIALS AND METHODS: Two hundred one patients with known or who were suspected of having HCC underwent multi–detector row CT; 58 patients with hypervascular HCC were identified. First-, second-, and third-phase scanning was started with the aortic arrival times plus 15 seconds, plus 30 seconds, and plus 105 seconds, respectively. All patients were assigned randomly into two groups. Patients in groups A and B received iopamidol with an iodine concentration of 300 mg/mL and 370 mg/mL, respectively, with the same total iodine load per patient per body weight. The liver and aorta enhancement and tumor-to-liver contrast (TLC) were measured. Depiction of hepatic arteries was evaluated visually by two radiologists.
RESULTS: During the first phase, aortic enhancement was significantly (P < .01) higher in group B, with no significant difference in hepatic enhancement between the two groups. During the second phase, aortic enhancement was significantly (P < .01) higher in group A, with no significant difference in hepatic enhancement. The TLC was significantly (P < .01) higher in group B during the first phase, but there was no significant difference between the two groups during the second phase. There was no significant difference in any parameters between the two groups during the third phase. Depiction of the hepatic arteries in group B was significantly (P < .05) superior to that in group A.
CONCLUSION: In the arterial phase, administration of a higher concentration of contrast material is effective for a significantly higher TLC.
© RSNA, 2002
Index terms: Computed tomography (CT), contrast enhancement • Computed tomography (CT), helical, 761.12115, 95.12915 • Hepatic arteries, CT, 95.12912, 95.12914, 95.12915 • Liver neoplasms, 761.323 • Liver neoplasms, CT, 761.12112, 761.12114, 761.12115
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
Multi–detector row helical CT has a high-volume-coverage speed performance (28). The entire liver is scanned in 5–10 seconds, and a double arterial phase scanning technique for the liver has been proposed (29,30).
The purpose of this study was to investigate the effect of different iodine concentrations on aortic and hepatic enhancement and the detectability of hypervascular HCC with multi–detector row helical CT and a uniphasic contrast material injection technique.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
-fetoprotein or proteins induced by vitamin K absence on antagonist II [PIVKA II]) were selected for this study. All patients were prospectively and randomly assigned into two groups by using a random-number table. Patients who had renal failure (serum creatine level >1.5 mg/dL [114 µmol/L]), congestive heart failure, respiratory failure, poor general condition, or a contraindication for iodinated contrast material were excluded from the study. Three patients were excluded from the study because of extravasation of contrast material. Eleven patients with tumor thrombi in the central portal or hepatic veins and extensive arterioportal shunts were excluded from the study. A total of 187 patients (129 men, 58 women; age range, 27–83 years; mean age, 65.4 years) were included.
Of the 187 patients, 80 patients had solitary or multiple HCC nodules. Proof of HCC was obtained with percutaneous liver biopsy (n = 3) or with measurement of substantially increased -fetoprotein or PIVKA II levels, with follow-up CT scans showing the progression of hepatic tumors (n = 77). Of the 80 patients with HCC, 22 had hypovascular and 58 had hypervascular tumors. We defined hypervascular tumors as tumors that showed an enhancement of 10 HU greater than that of the hepatic parenchyma in the first or second phase of contrast-enhanced scanning. The 58 patients included 45 men and 13 women (age range, 31–83 years; mean age, 65.7 years). The mean patient weight was 59.1 kg ± 8.1 (± SD) (range, 40–80 kg).
This study received institutional review board approval, and informed consent was obtained from all patients before CT examinations.
Contrast Material Infusion and CT Protocol
Two iodine concentrations (group A, 300 mg/mL; group B, 370 mg/mL) of iopamidol (Iopamiron; Nihon Schering, Osaka, Japan) with the same total iodine load per patient per body weight (518 mg per kilogram of body weight) were administered with a power injector (Autoenhance A-50; Nemoto-kyorindo, Tokyo, Japan) by using 18- or 20-gauge intravenous catheters inserted into an antecubital vein. The duration of the injection of the contrast material was 30 seconds in group A and 25 seconds in group B. Consequently, the injection rate of the contrast material per patient body weight was almost the same in the two groups (0.057 mL/sec/kg in group A and 0.056 mL/sec/kg in group B). Of 187 patients included in the study, 93 in group A received iopamidol with an iodine concentration of 300 mg/mL and 94 in group B received 370 mg/mL. Of 58 patients with hypervascular HCC, 28 in group A received iopamidol with an iodine concentration of 300 mg/mL and 30 in group B received 370 mg/mL.
All patients underwent multi–detector row CT (LightSpeed QX/i; GE Medical Systems, Milwaukee, Wis) with 0.8-second rotation time, 3.75-mm width, 5.0-mm image thickness and interval, pitch of 6, 50-cm scan field of view, 120 kV, and 220–280 mAs. These scanning parameters were selected to scan the entire liver as rapidly as possible without impairing image quality. All helical scans were obtained at the top of the liver in a cephalocaudal direction, and unenhanced and three-phase contrast-enhanced helical scans of the whole liver were obtained. The patients were instructed to hold their breath, with full exhalation during scanning.
The scanning delay was determined by administering a bolus of 15 mL of contrast material at the same rate as was used during helical scanning, followed by the acquisition of a series of single-level CT scans at low dose (120 kVp, 10 mA). The scanning location was the level of the celiac artery, and monitoring scans were acquired every 2 seconds from 10 to 30 seconds. A cursor was placed over the abdominal aorta at this level. A time-attenuation curve was constructed. The aortic arrival time, defined as the time from the initiation of contrast material injection to the upslope of the time-attenuation curve of the abdominal aorta, was measured. The contrast-enhanced helical scanning of the whole liver began at 15, 30, 105 seconds after the aortic contrast material arrival time (Fig 1).
|
In the aorta, attenuation values were measured on all images, and all attenuation values were averaged in each phase. An attempt was made to maintain a constant region of interest of approximately 1 cm2. The contrast enhancement in the aorta in each phase was calculated in the same way as was that in the hepatic parenchyma. In each case, we also calculated the absolute difference in the attenuation value between the aorta and the liver, that is, the aorta-to-liver contrast.
The conspicuity of the hepatic tumor can be expressed with attenuation differences between the hepatic tumor and the hepatic parenchyma, that is, the tumor-to-liver contrast (TLC) (31). TLC was defined as the attenuation of hepatic tumor minus the attenuation of hepatic parenchyma. We measured the TLC in each phase of contrast-enhanced scanning in 58 patients with hypervascular HCC. Tumor attenuation was measured in the most enhanced portion of the tumor. An attempt was made to maintain a region of interest of approximately 0.5 cm2. The attenuation values of the hepatic parenchyma used to calculate the TLC were measured in the normal hepatic parenchyma adjacent to the tumor. An attempt was made to maintain a constant region of interest of approximately 2 cm2. In cases with fewer than three tumors, TLC was measured and averaged in all tumors. In cases with three or more tumors, TLC was measured and averaged in the three largest tumors. The attenuation values of the aorta, the hepatic parenchyma, and the hypervascular HCC were measured by a radiologist (K.T.) who was unaware of the injection protocol.
Visual Analysis
Two radiologists who had no prior knowledge of the injection protocol qualitatively assessed the depiction of hepatic arteries. After an independent review, consensus was reached. The assessments of hepatic arteries were performed in the first and second phases of contrast-enhanced scanning. All images were printed by using a window level of 50 HU and a window width of 250 HU. We visually graded the depiction of hepatic arteries with the following four-point scale: 1, only common hepatic artery or celiac artery; 2, scale 1 and proper hepatic artery level; 3, scale 2 and the right or left hepatic artery; and 4, scale 3 and the segmental branches level of hepatic artery.
Statistical Analysis
The quantitative results of attenuation values were compared by using the Mann-Whitney U test, because only the data sets of groups A and B for the abdominal aorta in the third phase and TLC in the first phase of contrast-enhanced scanning showed normal distribution. Because of the discrete data, the visual analysis of the hepatic arteries between the two groups was also compared by using the Mann-Whitney U test. A P value of less than .05 was considered to indicate a statistically significant difference. To assess interobserver variability in the visual analysis, a 
statistic was calculated to measure the degree of agreement between the two observers.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
|
|
|
|
= 0.50).
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
Multi–detector row helical CT has the capability of scanning rapidly a large longitudinal volume (28), scanning the whole liver twice within 20–25 seconds. Murakami et al (30) recommended double arterial phase imaging with multi–detector row helical CT for improving the detection of hypervascular HCCs and reducing false-positive lesions. Foley et al (29) also reported double arterial phase imaging of the liver with a multi–detector row CT. They stated that the early arterial phase was useful in providing a volume data set for CT arteriography of the hepatic and mesenteric circulation and that the late arterial phase was the optimal phase for detecting hypervascular primary and metastatic neoplasms.
Foley et al (29) stated that early arterial phase scanning coincided with the maximum aortic enhancement of the test bolus. They administered contrast material at an injection rate of 5 mL/sec for 4 seconds for the test bolus and 5 mL/sec for 30 seconds for the multiphase acquisition. Theoretically, the time to maximum aortic enhancement is directly proportional to the injection duration for a given aortic arrival time (32). Therefore, initiation of first-phase scanning is 4 seconds after the aortic arrival time, and the maximum aortic peak is 30 seconds after the aortic arrival time. However, initiation of second-phase scanning is different in each patient because the second-phase scanning starts 5 seconds after the end of the first-phase scanning and the scanning time depends on the size of the liver. Thus, the relative timing of the second phase against the time-enhancement curve of the aorta is different in each case in the protocol of Foley et al.
With our protocols, the injection durations in groups A and B are 30 and 25 seconds, respectively. Therefore, the time to maximum aortic enhancement in groups A and B is theoretically 30 and 25 seconds, respectively. Consequently, initiation of first-phase scanning in both groups is theoretically always 15 seconds after the aortic arrival time, initiation of second-phase scanning in group A always theoretically coincides with the maximum aortic enhancement, and initiation of second-phase scanning in group B is always 5 seconds after the maximum aortic enhancement. In this way, we adopted scanning protocols that show almost constant time relationships between the scanning at each phase and the time-attenuation curves of the aorta. As a result, in our study, there was about a 10-second delay in the first and second phases compared with that in the studies of Foley et al.
Kim et al (33) studied the optimal phases of dynamic CT for detection of HCC, which included both hypervascular and hypovasucular HCC, and concluded that the combination of the arterial and late-phase imaging was best for the detection of HCC nodules. Mitsuzaki et al (4) also reported that CT during the arterial and delayed phases might be necessary for screening of patients who are suspected of having HCC. Therefore, we adopted a scanning protocol with three phases of contrast-enhanced scanning, that is, two early phases and one delayed phase, and omitted the portal venous phase scanning to minimize radiation exposure.
As mentioned earlier, we adopted a delayed phase scanning instead of a portal venous phase scanning in this study. However, in regard to the detection of hypovascular HCC, there is some discussion about whether the portal venous phase or the delayed phase is optimal. Some researchers (18,34–38) reported that TLC was maximized during the portal venous phase in some hypovascular HCCs. Conversely, Hwang et al (6) performed three-phase spiral CT examinations for the evaluation of nodular HCC and found that the number of lesions depicted on only delayed phase images was greater than those on only portal phase images. Also in the report by Mitsuzaki et al (4), the number of HCC nodules depicted on only delayed phase images was equal to the number of lesions depicted on only portal phase images. Therefore, in our study, we excluded hypovascular HCCs from the analysis of data of HCC.
To evaluate the effect of the iodine concentration in the contrast material in isolation, we administered contrast material with the same total iodine load (518 mg of iodine) and injection rate of 0.056 or 0.057 mL/sec per kilogram of patient body weight to the patients in both groups. Heiken et al (20) reported that a magnitude of hepatic peak enhancement of at least 50 HU is desirable based on a combination of quantitative and qualitative studies. The iodine dose required to achieve a hepatic enhancement level of 50 HU is 521 mg/kg. This iodine dose is almost equivalent to a volume of 1.4 mL/kg per patient body weight with 370 mg/mL of iopamidol or to a volume of 1.7 mL/kg per patient body weight with 300 mg/mL of iopamidol. Therefore, we administered almost the same dose of contrast material to each patient as did Heiken et al (20).
In our study during all phases, there was no significant difference in the mean hepatic enhancement between group B with higher iodine concentration and group A with lower iodine concentration. This lack of difference in the mean hepatic enhancement between the two groups during the first and second phases may be related to the dual blood supply of the liver (12). The liver receives approximately 30% of its blood supply from the hepatic artery and 70% from the portal vein. During the first phase, the total amount of contrast material that flows into the liver via the hepatic artery in group B was estimated, judging from the ratio of aortic enhancement between groups A and B, to be about 1.1-fold that in group A. Conversely, during the second phase, the total amount of contrast material in protocol A was estimated to be about 1.1-fold that in protocol B. The contrast material supplied by the hepatic artery is diluted with blood flow via the portal vein; consequently, the difference in the amount of contrast material that flows into the liver may be minimized between the two groups. On the other hand, the absence of a difference in the mean hepatic enhancement during the third phase may be explained by the facts that the total iodine load per patient body weight was the same in each group and that delayed scanning was performed during contrast material recirculation with continuous redistribution into the extravascular space.
On the basis of our results, aortic enhancement during the first phase was significantly higher in group B than in group A. This result suggests that aortic peak enhancement increases with higher iodine concentration at a given injection rate and total iodine load per patient body weight. Our result is comparable to a statement by Bae et al (32): "The magnitude of the peak contrast enhancement increases linearly with the total mass (concentration x volume) of iodine injected at a given injection rate." On the other hand, aortic enhancement in group B was significantly lower than that in group A during the second phase, that is, aortic enhancement with higher iodine concentration decreased rapidly compared with that with lower iodine concentration. This may be explained by the difference in the duration of the injection of contrast material between the two groups. In our study, the duration of injection in group B was 25 seconds, 5 seconds shorter than that in group A. Bae et al described that the time to aortic peak enhancement is directly proportional to the duration of injection for a given bolus transfer time. Thus, the possibility exists that the aortic peak enhancement in group B was reached sooner than that in group A, and aortic enhancement in group B decreased more rapidly in the second phase than that in group A.
The conspicuity of hypervascular HCC is related to the TLC (31). In general, hypervascular HCCs are fed by the hepatic artery. Because the hepatic artery is one of the major branches derived from the abdominal aorta, the concentration of contrast material in the hepatic artery is presumed to be almost equal to that of the abdominal aorta. Therefore, TLC is deduced to be parallel to the aorta-to-liver contrast in the arterial phase. In our study during the first phase, the aorta-to-liver contrast in group B was significantly higher than that in group A, and this result corresponded to the TLC in group B being significantly higher than that in group A. In contrast, during the second phase, the aorta-to-liver contrast in group A was significantly higher than that in group B. However, there was no significant difference in TLC between groups A and B. During this phase, the aorta-to-liver contrast was less than half of that during the first phase in both groups, and the difference in the aorta-to-liver contrast between groups A and B was only 15.3 HU. The degree of HCC enhancement is different with the histology type, the degree of differentiation, the tissue vascularity, an so forth, and it is necessarily supposed to be lower than that of the hepatic artery. Consequently, there may be no significant difference in TLC between groups A and B during the second phase.
In the visual analysis, the administration of a higher concentration of contrast material improved the depiction of hepatic arteries. Thus, it may also improve the image quality of CT angiography. CT angiography is beneficial for the preoperative evaluation for surgical resection, percutaneous ablation, or transarterial chemoembolization. A volume data set for CT angiography of the hepatic or superior mesenteric arteries can be obtained easily by using multi–dectector row helical CT, and the clinical demand for CT angiography will increase from now. The administration of a higher concentration of contrast material may also be useful for high-quality CT angiograms. However, it is necessary to keep in mind that the scanning technique used in this study (5-mm section thickness, 22.5 mm per rotation) is not suitable for adequate CT angiograms of the celiac and mesenteric arteries. A section thickness of 2.5 mm or less is required for adequate CT angiograms of these vessels.
This study has a potential limitation. In our study, tumor conspicuity, that is, TLC, in group B was significantly higher than that in group A during the first phase. However, we must be aware that tumor conspicuity does not directly correspond to tumor detectability. Even if tumor conspicuity is superior in the group with higher iodine concentration than it is with lower iodine concentration, it is possible that all hypervascular tumors are detected in both groups. To compare accurate detectability between the two groups, receiver operating characteristic curve analysis would be necessary in the future.
In summary, the administration of a higher concentration of contrast material could improve the depiction of hypervascular HCCs and the hepatic artery during the arterial phase compared with those with a lower concentration of contrast material, even though the total iodine load per patient body weight was the same. In general, the cost of contrast material for CT examinations depends on the total iodine amount in the contrast material. Thus, the diagnostic use of contrast-enhanced helical CT for hypervascular HCC may be increased by using a higher concentration of contrast material without an increase in cost.
|
FOOTNOTES |
|---|
3 Current address: Department of Radiology, Teikyo University School of Medicine, Itabashi-ku, Tokyo, Japan.
4 Current address: Department of Radiology, Sakai Municipal Hospital, Sakai City, Oskaka, Japan.
Abbreviations: HCC = hepatocellular carcinoma, TLC = tumor-to-liver contrast
Author contributions: Guarantors of integrity of entire study, K.A., S.H.; study concepts, K.A., K.T.; study design, K.A.; literature research, K.A., K.T.; clinical studies, K.A., K.T., H.O.; data acquisition, K.A., K.T., H.O.; data analysis/interpretation, K.A., K.T.; statistical analysis, K.A.; manuscript preparation, K.A.; manuscript definition of intellectual content and editing, K.A., S.H.; manuscript revision/review and final version approval, all authors.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODS RESULTSDISCUSSIONREFERENCES |
|---|
This article has been cited by other articles:
|
|
 |
|
  H. Kondo, M. Kanematsu, S. Goshima, Y. Tomita, T. Miyoshi, A. Hatcho, N. Moriyama, M. Onozuka, Y. Shiratori, and K. T. Bae Abdominal Multidetector CT in Patients with Varying Body Fat Percentages: Estimation of Optimal Contrast Material Dose Radiology, December 1, 2008; 249(3): 872 - 877. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. J. Phillips, D. L. Stella, W. M. Rozen, M. Ashton, and G. I. Taylor Abdominal Wall CT Angiography: A Detailed Account of a Newly Established Preoperative Imaging Technique Radiology, October 1, 2008; 249(1): 32 - 44. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Ma, A. E. Samir, N.-S. Holalkere, and D. V. Sahani Optimal Arterial Phase Imaging for Detection of Hypervascular Hepatocellular Carcinoma Determined by Continuous Image Capture on 16-MDCT Am. J. Roentgenol., September 1, 2008; 191(3): 772 - 777. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
X. Fei, X. Du, Q. Yang, Y. Shen, P. Li, J. Liao, and K. Li 64-MDCT Coronary Angiography: Phantom Study of Effects of Vascular Attenuation on Detection of Coronary Stenosis Am. J. Roentgenol., July 1, 2008; 191(1): 43 - 49. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. F. Behrendt, A. H. Mahnken, S. Stanzel, P. Seidensticker, E. Jost, R. W. Gunther, and G. Muhlenbruch Intraindividual Comparison of Contrast Media Concentrations for Combined Abdominal and Thoracic MDCT Am. J. Roentgenol., July 1, 2008; 191(1): 145 - 150. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Yanaga, K. Awai, T. Nakaura, T. Namimoto, S. Oda, Y. Funama, and Y. Yamashita Optimal Contrast Dose for Depiction of Hypervascular Hepatocellular Carcinoma at Dynamic CT Using 64-MDCT Am. J. Roentgenol., April 1, 2008; 190(4): 1003 - 1009. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. T. Schindera, R. C. Nelson, S. Mukundan Jr, E. K. Paulson, T. A. Jaffe, C. M. Miller, D. M. DeLong, K. Kawaji, T. T. Yoshizumi, and E. Samei Hypervascular Liver Tumors: Low Tube Voltage, High Tube Current Multi Detector Row CT for Enhanced Detection Phantom Study Radiology, December 1, 2007; 246(1): 125 - 132. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. L. Chu, B. N. Joe, A. C. A. Westphalen, E. M. Webb, F. V. Coakley, and B. M. Yeh Patient-specific Time to Peak Abdominal Organ Enhancement Varies with Time to Peak Aortic Enhancement at MR Imaging Radiology, December 1, 2007; 245(3): 779 - 787. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. M. Ho, R. C. Nelson, and D. M. DeLong Determining Contrast Medium Dose and Rate on Basis of Lean Body Weight: Does This Strategy Improve Patient-to-Patient Uniformity of Hepatic Enhancement during Multi-Detector Row CT? Radiology, May 1, 2007; 243(2): 431 - 437. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Goshima, M. Kanematsu, H. Kondo, R. Yokoyama, T. Miyoshi, H. Nishibori, H. Kato, H. Hoshi, M. Onozuka, and N. Moriyama MDCT of the liver and hypervascular hepatocellular carcinomas: optimizing scan delays for bolus-tracking techniques of hepatic arterial and portal venous phases. Am. J. Roentgenol., July 1, 2006; 187(1): W25 - W32. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Schima, R. Hammerstingl, C. Catalano, L. Marti-Bonmati, E. J. Rummeny, F. T. Montero, A. Dirisamer, B. Westermayer, M. Bellomi, D. Brisbois, et al. Quadruple-phase MDCT of the liver in patients with suspected hepatocellular carcinoma: effect of contrast material flow rate. Am. J. Roentgenol., June 1, 2006; 186(6): 1571 - 1579. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. T. Johnson and E. K. Fishman IV Contrast Selection for MDCT: Current Thoughts and Practice Am. J. Roentgenol., February 1, 2006; 186(2): 406 - 415. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Funama, K. Awai, Y. Nakayama, K. Kakei, N. Nagasue, M. Shimamura, N. Sato, S. Sultana, S. Morishita, and Y. Yamashita Radiation Dose Reduction without Degradation of Low-Contrast Detectability at Abdominal Multisection CT with a Low-Tube Voltage Technique: Phantom Study Radiology, December 1, 2005; 237(3): 905 - 910. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. T. Bae, K. Awai, and Y. Yamashita Comparison of Moderate versus High Concentration of Contrast Media Injected at the Same Total Iodine Dose and Fixed Injection Duration * Drs Awai and Yamashita respond: Radiology, August 1, 2005; 236(2): 740 - 741. [Full Text] [PDF]
|
|
|
|
|
|
Y. Yagyu, K. Awai, M. Inoue, R. Watai, T. Sano, H. Hasegawa, and Y. Nishimura MDCT of Hypervascular Hepatocellular Carcinomas: A Prospective Study Using Contrast Materials with Different Iodine Concentrations Am. J. Roentgenol., May 1, 2005; 184(5): 1535 - 1540. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Awai, M. Inoue, Y. Yagyu, M. Watanabe, T. Sano, S. Nin, R. Koike, Y. Nishimura, and Y. Yamashita Moderate versus High Concentration of Contrast Material for Aortic and Hepatic Enhancement and Tumor-to-Liver Contrast at Multi-Detector Row CT Radiology, December 1, 2004; 233(3): 682 - 688. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Saini Multi-Detector Row CT: Principles and Practice for Abdominal Applications Radiology, November 1, 2004; 233(2): 323 - 327. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Furuta, K. Ito, T. Fujita, S. Koike, A. Shimizu, and N. Matsunaga Hepatic Enhancement in Multiphasic Contrast-Enhanced MDCT: Comparison of High- and Low-Iodine-Concentration Contrast Medium in Same Patients with Chronic Liver Disease Am. J. Roentgenol., July 1, 2004; 183(1): 157 - 162. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Murakami, T. Kim, M. Hori, and M. P. Federle Double Arterial Phase Multi-Detector Row Helical CT for Detection of Hypervascular Hepatocellular Carcinoma [letter] Radiology, December 1, 2003; 229(3): 931 - 932. [Full Text] [PDF]
|
|
| ||||||||||||||||
shows outliers of the data.
