Detection of hypervascular nodular hepatocellular carcinomas: value of triphasic helical CT compared with iodized-oil CT

Realization of real-time X-ray stereoscopic vision during interventional procedures

During interventional procedures, the deficiencies of nonstereoscopic vision increase the difficulty of identifying the anteroposterior direction and pathways of vessels. Therefore, achieving real-time stereoscopic vision during interventional procedures is meaningful. Pairs of X-ray images were captured with identical parameter settings, except for different rotation angles (represented as the α angle). The resulting images at these α angles were used as left-eye and right-eye views and were horizontally merged into single left-right 3D images. Virtual reality (VR) glasses were used for achieving stereo vision. Pairs of X-ray images from four angiographies with different α angles (1.8-3.4°) were merged into left-right 3D images. Observation with VR glasses can produce realistic stereo views of vascular anatomical structure. The results showed that the optimal α angles accepted by the brain for generating stereo vision were within a narrow range (approximately 1.4-4.1°). Subsequent tests showed that during transcatheter arterial chemoembolization, 3D X-ray stereoscopic images provided significantly improved spatial discrimination and convenience for identifying the supply vessels of a liver tumor and its anteroposterior direction compared with plain X-ray images (all P < 0.01). Real-time X-ray stereoscopic vision can be easily achieved via the straightforward method described herein and has the potential to benefit patients during interventional procedures.

Using receiver operating characteristic curves to evaluate the diagnostic value of the combination of multislice spiral CT and alpha-fetoprotein levels for small hepatocellular carcinoma in cirrhotic patients

BACKGROUND

The various combination of multiphase enhancement multislice spiral CT (MSCT) makes the diagnosis of a small hepatocellular carcinoma (sHCC) on the background of liver cirrhosis possible. This study was to explore whether the combination of MSCT enhancement scan and alpha-fetoprotein (AFP) level could increase the diagnostic efficiency for sHCC.

METHODS

This study included 35 sHCC patients and 52 cirrhotic patients without image evidence of HCC as a control group. The diagnoses were made by three radiologists employing a 5-point rating scale, with postoperative pathologic results as the gold standard. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic value of the three MSCT combination modes (arterial phase+portal-venous phase, arterial phase+delayed phase, arterial phase+portal-venous phase+delayed phase) and AFP levels for sHCC on the background of liver cirrhosis.

RESULTS

The area under ROC curve (AUC), sensitivity, and specificity of the combination of arterial phase+portal-venous phase+delayed phase were 0.93, 93%, and 82%, respectively. The average AUC of the arterial phase+portal-venous phase+delayed phase combination was significantly greater than that of the arterial phase+portal-venous phase (AUC=0.84, P=0.01) and arterial phase+delayed phase (AUC=0.85, P=0.03). Arterial phase+portal-venous phase had a smaller AUC (0.84) than arterial phase+delayed phase (0.85), but the difference was insignificant (P=0.15). After combining MSCT enhancement scan with AFP, the AUC, sensitivity, and specificity were 0.95, 94%, and 83%, respectively, indicating a greatly increased diagnostic efficiency for sHCC.

CONCLUSIONS

The combination of AFP and 3 phases MSCT enhancement scan could increase the diagnostic efficiency for sHCC on the background of liver cirrhosis. The application of ROC curve analysis has provided a new method and reference in HCC diagnosis.

Effect of PDCA circulation method on quality of reusable instrument centralized sterilization

AIM

To investigate the effect of the plan-do-check action cycle (PDCA) method on the quality of reusable instrument centralized sterilization.

METHODS

A comparative analysis was carried out to examine the quality of reusable instrument centralized disinfection before and after PDCA management method was applied between November 2105 and December 2014.

RESULTS

One year after the implementation of PDCA, the rate of qualified disinfection was 100%, the rate of instrument loss was 0.25%, the normal rate of disinfection equipment was 98.7%, and the rate of device associated rate was 0%. Compared with those before the implementation of PDCA, instrument reuse quality improved significantly (P < 0.05). After the implementation of PDCA, the rate of satisfaction to packaging was 98.9% and the rate of staff satisfaction was 98.5%, both of which were significantly higher than those before the implementation of PDCA (P < 0.05).

CONCLUSION

The use of PDCA circulation method can significantly improve the disinfection quality of reusable instruments and the staff satisfaction to reusable instruments, and can thus provide more reliable and safe therapeutic instruments for patients.

CT Appearance of Hepatocellular Carcinoma after Locoregional Treatments: A Comprehensive Review

Hepatocellular carcinoma (HCC) is a major health problem worldwide, affecting more than 600,000 new patients per year. Curative treatments are available in a small percentage of patients, while most of them present in stages requiring locoregional treatments such as thermoablation, transarterial chemoembolization, and/or radioembolization. These therapies result in specific imaging features that the general radiologist has to be aware of in order to assess the response to treatment and to correctly manage the follow-up of treated patients. Multiphasic helical computed tomography has become a popular imaging modality for detecting hypervascular tumors and characterizing liver lesions. On this basis, many staging and diagnostic systems have been proposed for evaluating response to all different existing strategies. Radiofrequencies and microwaves generate thermoablation of tumors, and transarterial chemoembolization exploits the double effect of the locoregional administration of drugs and embolizing particles. Eventually radioembolization uses a beta-emitting isotope to induce necrosis. Therefore, the aim of this comprehensive review is to analyze and compare CT imaging appearance of HCC after various locoregional treatments, with regard to specific indications for all possible procedures.

Contrast Enhanced MRI in the Diagnosis of HCC

Hepatocellular carcinoma (HCC) is the 6th most common cancer worldwide. Imaging plays a critical role in HCC screening and diagnosis. Initial screening of patients at risk for HCC is performed with ultrasound. Confirmation of HCC can then be obtained by Computed Tomography (CT) or Magnetic Resonance Imaging (MRI), due to the relatively high specificity of both techniques. This article will focus on reviewing MRI techniques for imaging HCC, felt by many to be the exam of choice for HCC diagnosis. MRI relies heavily upon the use of gadolinium-based contrast agents and while primarily extracellular gadolinium-based contrast agents are used, there is an emerging role of hepatobiliary contrast agents in HCC imaging. The use of other non-contrast enhanced MRI techniques for assessing HCC will also be discussed and these MRI strategies will be reviewed in the context of the pathophysiology of HCC to help understand the MR imaging appearance of HCC.

The ins and outs of liver imaging

Different imaging modalities including ultrasonography, computed tomography (CT), and MR imaging may be used in the liver depending on the clinical situation. The ability of dedicated contrast-enhanced liver MR imaging or CT to definitively characterize lesions as benign is crucial in avoiding unnecessary biopsy. Liver imaging surveillance in patients with cirrhosis may allow for detection of hepatocellular carcinoma at an earlier stage, and therefore may improve outcome. This article reviews the different imaging modalities used to evaluate the liver and focal benign and malignant hepatic lesions, and the basic surveillance strategy for patients at increased risk for hepatocellular carcinoma.

Characterization of 1-to 2-cm liver nodules detected on hcc surveillance ultrasound according to the criteria of the American Association for the Study of Liver Disease: is quadriphasic CT necessary?

OBJECTIVE

The purpose of this study was to identify the essential number of phases from multiphasic CT for 1- to 2-cm hepatocellular carcinoma (HCC) on surveillance ultrasound and to compare the results with the American Association for the Study of Liver Disease (AASLD) standard (arterial phase hypervascularity and portal venous phase [PVP] or delayed phase hypovascularity).

MATERIALS AND METHODS

The study included 110 newly detected nodules (1-2 cm; 36 HCC, 74 benign) in 96 patients detected in an HCC surveillance program. Three radiologists prospectively evaluated the attenuation of each nodule relative to the liver on each phase of quadriphasic CT. Univariate and multivariate logistic regression analyses were used to identify parameters associated with HCC. Multiple combinations of phases were compared with the AASLD standard.

RESULTS

Only arterial phase hypervascularity and delayed phase hypovascularity were significantly associated with HCC both on univariate (odds ratio, arterial phase 7.51 [95% CI, 2.79-20.20]; delayed phase, 2.80 [1.14-6.90]) and multivariate analyses (arterial phase, 11.30 [4.30-29.68]; delayed phase, 4.39 [1.20-16.13]). The combination of arterial phase and delayed phase yielded the highest specificity (99%) and sensitivity (57%). There was no significant difference between AASLD standard (sensitivity, 57%; specificity, 98%) versus biphasic (arterial phase hypervascularity and delayed phase hypovascularity: sensitivity, 57%; p = 1 and specificity, 99%; p = 0.32), triphasic (arterial phase hypervascularity and unenhanced or PVP hypovascularity: sensitivity, 53%; p = 0.325 and specificity, 97%; p = 0.32), or quadriphasic combination (arterial phase hypervascularity and unenhanced, PVP or delayed phase hypovascularity: sensitivity, 57%; specificity, 97%), whereas the sensitivity of biphasic arterial phase and PVP was significantly lower (39% vs 57%, p = 0.022).

CONCLUSION

For diagnosing 1- to 2-cm HCC detected on surveillance ultrasound, arterial phase and delayed phase are two essential phases, providing higher sensitivity than the combination of arterial phase and PVP, and equal performance with triphasic and quadriphasic combinations. The biphasic combination of arterial phase and delayed phase may replace quadriphasic CT recommended by AASLD.

Detection of hepatocellular carcinoma by Gd-EOB-DTPA-enhanced liver MRI: comparison with triple phase 64 detector row helical CT

PURPOSE

To compare the diagnostic performance of Gd-EOB-DTPA-enhanced MRI with that of triple phase 64-MDCT in the detection of hepatocellular carcinoma (HCC).

PATIENTS AND METHODS

Thirty-four patients with 52 surgically proven lesions underwent Gd-EOB-DTPA-enhanced MRI and triple phase 64-MDCT. Two observers independently evaluated MR and CT imaging on a lesion-by-lesion basis. Sensitivity, positive and negative predictive values and reproducibility were evaluated. The diagnostic accuracy of each modality was assessed with alternative-free response receiver operating characteristic (ROC) analysis.

RESULTS

Both observers showed higher sensitivity in detecting lesions with MRI compared to CT, however, only the difference between the two imaging techniques for observer 2 was significant (P=0.034). For lesions 1cm or smaller, MRI and CT showed equal sensitivity (both 62.5%) with one observer, and MRI proved superior to CT with the other observer (MRI 75% vs. CT 56.3%), but the latter difference was not significant (P=0.083). The difference in positive and negative predictive value between the two imaging techniques for each observer was not significant (P>0.05). The areas under the ROC curve for each observer were 0.843 and 0.861 for MRI vs. 0.800 and 0.833 for CT and the differences were not significant. Reproducibility was higher using MRI for both observers, but the result was not significant (MRI 32/33 vs. CT 29/33, P=0.083).

CONCLUSION

Gd-EOB-DTPA-enhanced MRI tended to show higher diagnostic accuracy, sensitivity and reproducibility compared to triple phase 64-MDCT in the detection of hepatocellular carcinoma, however statistical significance was not achieved.

[Multidetector computed tomography of the liver]

Multidetector-row CT (MDCT) scanners have dramatically improved liver imaging. With the newest generation of 40-64 row scanners, true isotropic imaging with a z-axis resolution of 0.3-0.6 mm has become possible. Acquisition time for the scan has been shortened to a few seconds. To fully exploit the advantages of MDCT scanners in liver imaging, the examination protocols have to be optimized with regard to contrast material flow rate, scan delay, and the number of scans performed. The possible advantages of double arterial phase scans in the detection of HCC are discussed. The clinical value of 3D reconstructions, such as multiplanar reconstructions and curved planar reconstructions, for assessment of the vascular and biliary duct infiltration is demonstrated. Optimized MDCT imaging improves detection and characterization of focal liver lesions.

Iodized oil accumulation in hypervascular hepatocellular carcinoma after transcatheter arterial chemoembolization: comparison of imaging findings with CT during hepatic arteriography

PURPOSE

To compare the degree of tumor enhancement seen on computed tomography (CT) during hepatic arteriography (CT/HA) performed before transcatheter arterial chemoembolization (TACE) versus that determined based on the accumulation of iodized oil seen on CT images obtained after TACE in patients with hypervascular hepatocellular carcinoma (HCC) and evaluate the discrepancy in findings between the two imaging modalities (more or less oil accumulation after TACE compared with enhancement on CT/HA).

MATERIALS AND METHODS

CT/HA, TACE, and iodized oil CT after TACE were performed in 69 patients with 83 hypervascular HCCs with use of an interventional CT system. The degree of contrast enhancement of the lesion on CT/HA and the iodized oil accumulation on unenhanced CT after TACE were compared.

RESULTS

Among 83 HCCs, the degree of enhancement on CT/HA before TACE corresponded to the iodized oil accumulation on CT in 56 (67.5%). Fifteen of 83 HCCs (18%) showed incomplete or poor accumulation of iodized oil despite good enhancement on CT/HA images. Twelve of 83 HCCs (14.5%) showed moderate or complete accumulation of iodized oil despite poor or no enhancement on CT/HA images. In particular, in two patients with occluded portal veins, iodized oil did not accumulate in the tumor despite good visualization on CT/HA.

CONCLUSIONS

Although iodized oil accumulation in hypervascular HCCs correlates with the degree of lesion enhancement on CT/HA in most cases, a discrepancy may occur in a substantial number of cases, which likely affects the prediction of therapeutic effects in hypervascular HCCs.

Pre-operative transarterial chemoembolization for resectable hepatocellular carcinoma adversely affects post-operative patient outcome

BACKGROUND

Long-term outcomes after hepatic resection for hepatocellular carcinoma are not satisfactory because of high recurrence rates. Aim To assess whether a single session of pre-operative transarterial chemoembolization affects post-operative outcome.

METHODS

We analysed outcomes retrospectively in 334 consecutive patients who underwent hepatic resection for hepatocellular carcinoma, initially judged resectable. Ninety-seven of these patients had each undergone a single session of pre-operative transarterial chemoembolization (transarterial chemoembolization + hepatic resection group), whereas 237 had not (hepatic resection group).

RESULTS

Most clinicopathological characteristics were similar in the two groups. The overall survival rate was significantly higher in the hepatic resection than in the transarterial chemoembolization + hepatic resection group (P = 0.011), whereas their disease-free survival rates were comparable (P = 0.67). The overall and disease-free survival rates of the transarterial chemoembolization + hepatic resection group with incomplete tumour necrosis were significantly lower than those of the hepatic resection group (P < 0.001 and P = 0.006, respectively). Multivariate analysis showed that pre-operative transarterial chemoembolization, serum alpha-fetoprotein elevation (>1000 ng/mL), tumour size (>5 cm) and vascular invasion were independent risk factors for poor overall survival after hepatic resection.

CONCLUSIONS

A single session of pre-operative transarterial chemoembolization for initially resectable hepatocellular carcinoma worsens overall survival rate. It may also increase the risk of tumour recurrence in patients who achieve incomplete tumour necrosis.

Small hepatocellular carcinomas in cirrhosis: differences in contrast enhancement effects between helical CT and MR imaging during multiphasic dynamic imaging

PURPOSE

The purpose of this study was to evaluate differences in the degrees of contrast enhancement effects of small hepatocellular carcinomas (HCCs) in patients with cirrhosis between helical computed tomography (CT) and magnetic resonance (MR) imaging during multiphasic contrast-enhanced dynamic imaging and to determine the diagnostic value of MR imaging especially in assessing hypovascular HCCs detected as hypoattenuating nodules on late-phase CT.

SUBJECTS AND METHODS

This study included 64 small HCCs (<3 cm in diameter) in 40 patients with chronic hepatitis or cirrhosis who underwent multiphasic (arterial, portal and late phases) contrast-enhanced dynamic helical CT and MR imaging. The contrast enhancement patterns of each lesion in the arterial and late phases were evaluated by two radiologists experienced in liver MR imaging and categorized as one of five grades (1=hypoattenuated/hypointense; 2=slightly hypoattenuated/hypointense; 3=isoattenuated/isointense; 4=slightly hyperattenuated/hyperintense; 5=hyperattenuated/hyperintense), compared with the surrounding liver parenchyma.

RESULT

Forty-three (67%) of 64 lesions showed Grade 4 (n=24) or Grade 5 (n=19) enhancement on arterial-phase CT, while 51 (80%) of 64 lesions showed Grade 4 (n=20) or Grade 5 (n=31) enhancement on arterial-phase MR imaging, indicating hypervascular HCCs. The grading score of hypervascular HCCs on arterial-phase MR imaging (mean: 4.61) was significantly (P<.01) higher than that for hypervascular HCCs on arterial-phase CT (mean: 4.20), showing better detection of the hypervascularity (arterial enhancement) of the lesion on arterial-phase MR imaging. Regarding hypovascular HCCs, all (100%) of 21 hypovascular HCCs on CT showed Grade 1 (n=10) or Grade 2 (n=11) enhancement on late-phase CT, seen as hypoattenuation. In contrast, 8 (62%) of 13 hypovascular HCCs on MR imaging showed Grade 1 (n=1) or Grade 2 (n=7) enhancement on late-phase MR imaging, seen as hypointensity. Grading scores of hypovascular HCCs on late-phase images were significantly (P<.001) lower on CT than on MR imaging (mean score: 1.52 vs. 2.31), indicating better washout effects for hypovascular HCCs on late-phase CT.

CONCLUSION

The washout effects for small HCCs on late-phase MR imaging were inferior to those for small HCCs on late-phase CT. Especially, hypovascular HCCs demonstrated as hypoattenuating nodules on late-phase CT were often not seen on late-phase MR imaging, requiring careful evaluation of other sequences, including unenhanced T(1)-weighted and T(2)-weighted MR images.

[Diagnostic radiology of liver tumors. Part 1: General disease aspects and radiological procedures]

Besides malignant disease, focal liver lesions can also represent benign changes. Among the malignant lesions, in addition to hepatocellular carcinoma, liver metastases should be mentioned. In contrast, benign lesions such as focal nodular hyperplasia and hepatocellular adenoma are rarely encountered. Various radiological procedures are employed for the (differential) diagnosis. The transabdominal ultrasound examination is supplemented by color Doppler procedures, contrast-enhanced or intraoperative ultrasound. Computed tomography (CT) should be performed with native images as well as after using modern nonionic, iodine-containing water-soluble contrast agents; multidetector spiral CT is today's standard. If comparable optimal technology is available on-site, (contrast-enhanced) MRI is preferable. Intra-arterial selective angiography has become less important for detecting and characterizing focal liver changes with the advent of tomographic procedures. The question of whether sonography- or CT-guided biopsy of the liver is needed for further diagnostic work-up, whether a wait-and-see approach is justified, or whether surgery is required to clarify the diagnosis should always be answered on a case-by-case basis.

Detection of Hepatocellular Carcinoma on CT in Liver Transplant Candidates: Comparison of PACS Tile and Multisynchronized Stack Modes

OBJECTIVE

The objective of our study was to compare CT image interpretation using PACS tile and multisynchronized stack modes with respect to speed and observer performance for the detection of hepatocellular carcinoma (HCC) in liver transplant candidates.

MATERIALS AND METHODS

Institutional review board approval was obtained, but informed consent was not required for this retrospective study. Sixty-seven patients underwent dynamic multiphasic CT within 3 months before liver transplantation. Interval reviews using tile and multisynchronized stack modes were performed independently by four reviewers with various levels of experience to determine the presence of HCC using a five-point confidence scale. Observer performance was compared using jackknife free-response receiver operating characteristic (ROC) analysis. The time required to interpret the CT scans using each mode was recorded and compared using the paired Student's t test.

RESULTS

Twenty-seven patients had 48 HCC nodules. The mean free-response ROC figures of merit for detecting HCC were significantly higher using the multisynchronized stack mode (0.731) than using the tile mode (0.662) (F-statistic = 6.603, p = 0.012). The 95% CIs for the task were -0.125 - -0.016. The time used for image analysis was also significantly shorter with the stack mode (63 to approximately 75 seconds) than with the tile mode (94 to approximately 191 seconds) for all four reviewers (p < 0.0001).

CONCLUSION

Multisynchronized stack viewing of multiphasic dynamic CT scans significantly increases the detection rate of HCC in liver transplant candidates. It also significantly shortens the interpretation time compared with tile viewing.

Dynamic CT for detecting small hepatocellular carcinoma: usefulness of delayed phase imaging

OBJECTIVE

The purpose of this retrospective study was to determine the usefulness of delayed phase imaging for detecting small (< or = 2 cm) hepatocellular carcinomas (HCCs) in patients with liver cirrhosis.

MATERIALS AND METHODS

Triphasic (arterial, portal venous, and delayed phases) dynamic CT was performed in 33 patients with 48 HCCs proven histopathologically and in 65 control subjects. Arterial, portal venous, and delayed phase images were obtained 30 seconds, 68-70 seconds, and 5 minutes after the start of contrast material injection, respectively. Three blinded observers reviewed the images independently and evaluated tumor attenuation. Diagnostic performance for the combination of phases was assessed using receiver operating characteristic (ROC) curve analysis.

RESULTS

On arterial phase images, 28 of the 48 HCCs were hyperattenuating, nine were isoattenuating, and 11 were hypoattenuating. On portal venous phase images, three tumors were hyperattenuating, 17 were isoattenuating, and 28 were hypoattenuating. On delayed phase images, five tumors were isoattenuating, and 43 were hypoattenuating. The mean sensitivity for the combination of arterial and portal venous phase imaging was 86.8%, that for the combination of arterial and delayed phase imaging was 90.3%, and that for the combination of all three phase imaging was 93.8%. The area underneath composite ROC curve (A(Z)) for the combination of all three phase imaging (A(Z) = 0.940) was significantly higher than that for the combination of arterial and portal venous phase imaging (A(Z) = 0.917) and for the combination of arterial and delayed phase imaging (A(Z) = 0.922).

CONCLUSION

Delayed phase imaging is useful for detecting small HCCs and should be included in dynamic CT examinations of patients with liver cirrhosis.

Imaging well-differentiated hepatocellular carcinoma with dynamic triple-phase helical computed tomography

To investigate the imaging appearance of well-differentiated hepatocellular carcinoma (HCC) on dynamic CT, a total of 38 histopathologically proven well-differentiated HCC were included in a retrospective study. We reviewed the contrast-enhanced dynamic CT of all 38 tumours for attenuation of each tumour in unenhanced scan, arterial-dominant and delayed portal venous phases. Our results showed that dynamic CT identified 26 (68.4%) out of the 38 lesions. The remaining 12 lesions were isodense compared with surrounding liver parenchyma in each dynamic CT phase. There was no statistically significant difference between the mean size of tumours detected by dynamic CT and that of tumours not detected by dynamic CT (p = 0.1). Of a total of 38 tumours, most were isodense (n = 19) or hypodense (n = 16) in unenhanced scan, mostly hyperdense (n = 18) or isodense (n = 15) in arterial-dominant phase and mostly isodense (n = 22) or hypodense (n = 15) in delayed portal venous phase. Enhancement of tumour was observed in 19 (50.0%) of 38 lesions. In conclusion, the ability of dynamic CT to detect well-differentiated HCC is poor, and negative CT findings cannot exclude the presence of well-differentiated HCC, especially if there is well-grounded clinical suspicion for HCC.

Indeterminate small, low-attenuating hepatocellular nodules on helical CT in patients with chronic liver disease: 2-year follow-up

To evaluate the clinical significance of indeterminate, small, low-attenuating nodular lesions on helical dynamic computed tomography (CT) in chronic liver diseases, CT images were reviewed retrospectively in 281 patients. Indeterminate, low-attenuating nodular lesions less than 20 mm in diameter were followed for 24 to 35 months. Of 127 nodules in 73 patients, 21 nodules turned out to be hepatocellular carcinomas (16%), 25 nodules (20%) became larger, while the remaining 81 nodules (64%) remained unchanged or disappeared. Some low-attenuating nodules larger than 10 mm in diameter may develop into hepatocellular carcinoma.

Imaging diagnosis of hepatocellular carcinoma with differentiation from other pathology

Recent advances in liver imaging techniques and better understanding of imaging findings have facilitated the detection and characterization of hepatocellular nodules in a cirrhotic liver. It is important to recognize that various types of benign nodules and pseudolesions are identified on all imaging scans performed for the diagnosis of hepatocellular carcinoma. An accurate differentiation between them is critical for adequate management of cirrhotic patients. Unfortunately, any of the imaging tests and even percutaneous biopsy are not diagnostic for borderline lesions. Intimate collaboration of hepatologists, pathologists, surgeons, and radiologists with reasonable imaging and clinical criteria estimating the degree of malignancy is imperative.

MDCT of Hypervascular Hepatocellular Carcinomas: A Prospective Study Using Contrast Materials with Different Iodine Concentrations

OBJECTIVE

The objective of our study was to investigate the effect of different iodine concentrations in contrast materials on the depiction of hypervascular hepatocellular carcinomas (HCCs) by MDCT.

SUBJECTS AND METHODS

This prospective study involved 100 consecutive patients with chronic liver disease, including 27 patients with hypervascular HCCs. The first 50 patients received 100 mL of iopamidol at a concentration of 370 mg I/mL (group A) and the subsequent 50, 100 mL at 300 mg I/mL (group B); in both groups, the contrast material was administered at a rate of 3.0 mL/sec. Unenhanced scanning and four-phase enhanced scanning at 25, 40, 60, and 180 sec after the start of contrast injection were performed. The enhancement of the aorta, liver, and portal vein was measured during each phase. In addition, tumor-to-liver contrast was calculated for the 27 patients with hypervascular HCCs. Of the 27 patients with hypervascular HCCs, 15 were in group A and 12 were in group B.

RESULTS

During all phases, aortic enhancement was significantly greater in group A than group B (p < 0.01). Hepatic enhancement was significantly greater in group A than group B at 60 and 180 sec (both p < 0.01). There was no significant difference in hepatic enhancement between the two groups at 25 and 40 sec. Tumor-to-liver contrast was significantly greater in group A than group B during the late arterial phase (40 sec, p = 0.02), although there was no significant difference at 25, 60, and 180 sec.

CONCLUSION

Contrast materials with higher iodine concentration are more effective for depicting hypervascular HCCs on MDCT during the late arterial phase.

Hepatocellular carcinoma: role of unenhanced and delayed phase multi-detector row helical CT in patients with cirrhosis

PURPOSE

To determine, by using multi-detector row helical computed tomography (CT), the added value of obtaining unenhanced and delayed phase scans in addition to biphasic (hepatic arterial and portal venous phases) scans in the detection of hepatocellular carcinoma (HCC) in patients with cirrhosis.

MATERIALS AND METHODS

Local ethical committee approval and patient consent were obtained. One hundred ninety-five patients (129 men, 66 women; mean age, 61 years; age range, 39-78 years) with 250 HCCs underwent multi-detector row helical CT of the liver. A quadruple-phase protocol that included unenhanced, hepatic arterial, portal venous, and delayed phases was performed. Analysis of images from hepatic arterial and portal venous phases combined, hepatic arterial and portal venous phases with the unenhanced phase, hepatic arterial and portal venous phases with the delayed phase, and all phases combined was performed separately by three independent radiologists. Relative sensitivity, positive predictive value, and area under the receiver operating characteristic curve (A(z)) were calculated for each reading session.

RESULTS

Mean sensitivity and positive predictive values, respectively, for HCC detection were 88.8% (666 of 750 readings) and 97.8% (666 of 681 readings) for the combined hepatic arterial and portal venous phases, 89.2% (669 of 750 readings) and 97.8% (669 of 684 readings) for hepatic arterial and portal venous phases with the unenhanced phase, 92.8% (696 of 750 readings) and 97.3% (696 of 715 readings) for hepatic arterial and portal venous phases with the delayed phase, and 92.8% (696 of 750 readings) and 97.3% (696 of 715 readings) for all four phases combined. The reading sessions in which delayed phase images were available for interpretation showed significantly (P < .05) superior sensitivity and A(z) values.

CONCLUSION

Unenhanced phase images are not effective for HCC detection. Because of the significant increase in HCC detection, a delayed phase can be a useful adjunct to biphasic CT in patients at risk for developing HCC.

Spiral computed tomography versus ultrasound in the follow-up of cirrhotic patients previously treated for hepatocellular carcinoma: a prospective study

BACKGROUND/AIMS

To assess the value of hepatic-arterial-phase computed tomography (HAP-CT) versus ultrasound (US) plus alpha-fetoprotein (AFP) in the surveillance of cirrhotic patients with previously treated hepatocellular carcinoma (HCC).

METHODS

Thirty-six cirrhotic patients, treated for single nodular HCC <4cm with complete response and no evidence of other focal lesions, were enrolled in a prospective study and underwent simultaneous AFP/US/spiral-CT follow-up every 6 months. Focal lesions were considered recurrences when they appeared as globular enhancement areas (EA) at HAP-CT and increased in size during the follow-up.

RESULTS

Fifteen of 36 patients showed at least one focal lesion for a total of 43 EA: 38/43 increased in size, four did not change and one disappeared. EA were first observed after a follow-up of 9+/-4 (range 6-18) months. At the same time, no patient had either nodular lesion at US examination or diagnostic levels of AFP. In 22 matched lesions, diagnosis by CT was 8.2+/-3.5 months earlier than by US. In 13 patients, one evolved EA was submitted to US-guided biopsy and histological examination showed HCC in all cases.

CONCLUSIONS

Periodical spiral-CT examination is more effective than US-AFP in early detection of HCC recurrence in cirrhotic patients successfully treated for HCC.

Hepatic arterial and portal venous phase helical CT in patients treated with transcatheter arterial chemoembolization for hepatocellular carcinoma: added value of unenhanced images

PURPOSE

To evaluate the additional diagnostic value of unenhanced computed tomographic (CT) images in the depiction of viable tumor in patients who were treated with transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) and followed up with biphasic helical CT that included the acquisition of unenhanced images.

MATERIALS AND METHODS

We performed helical CT (with unenhanced, arterial, and portal phases) in 54 patients who had been treated with TACE for HCC. Image analysis was first performed with only those images obtained in the arterial and portal venous phases of helical CT. A second analysis was then performed with unenhanced images, arterial images, and portal venous images that focused on the additional value of unenhanced images. The value of additional unenhanced images was evaluated by means of interobserver agreement (kappa statistic) and receiver operating characteristic (ROC) analysis.

RESULTS

The two readers detected 128 and 129 lesions. Unenhanced images were valuable for 32 of 129 lesions (23 patients) for reader 1 and for 29 of 128 lesions (21 patients) for reader 2. Although there was no significant difference between biphasic CT alone and biphasic CT with unenhanced images, results of ROC analysis showed higher diagnostic performance with biphasic CT with unenhanced images than with biphasic CT alone for detecting viable tumor.

CONCLUSION

The study data demonstrate the diagnostic value of unenhanced images interpreted in conjunction with biphasic CT images for follow-up of patients who have previously been treated with TACE for HCC.

Aortic and hepatic enhancement and tumor-to-liver contrast: analysis of the effect of different concentrations of contrast material at multi-detector row helical CT

PURPOSE

To investigate the effect of different iodine concentrations of contrast material on aortic and hepatic enhancement and the detectability of hypervascular hepatocellular carcinoma (HCC) with multi-detector row computed tomography (CT) and a uniphasic contrast material injection technique.

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.

Detection of hepatocellular carcinoma: comparison of dynamic three-phase computed tomography images and four-phase computed tomography images using multidetector row helical computed tomography

PURPOSE

The purpose of our study was to assess the value of additional early arterial phase computed tomography (CT) imaging in the detection of hepatocellular carcinoma (HCC) by comparing three-phase and four-phase imaging by using multidetector row helical CT.

METHODS

Twenty-five patients with 33 HCCs underwent four-phase helical CT imaging. The diagnosis was established by pathologic examination after surgical resection in 19 patients and by biopsy in six. Four-phase CT imaging comprises early arterial, late arterial, portal venous, and delayed phase imaging obtained 25 seconds, 45 seconds, 75 seconds, and 180 seconds after the start of contrast material injection using multidetector row helical CT. Three-phase CT images (late arterial, portal venous, and delayed phase) and four-phase CT images (early arterial, late arterial, portal venous, and delayed phase) were interpreted independently for the detection of HCC by three blinded observers on a segment-by-segment basis. Sensitivity, specificity, and area under the receiver operating characteristic (ROC) curve (Az) for three-phase CT images and four-phase CT images were calculated. The enhancement pattern of HCC was analyzed on early arterial and late arterial phase imaging.

RESULTS

The mean sensitivity of three- and four-phase CT images was 94% and 93%, respectively. The differences between sensitivities were not statistically significant (all p > 0.05). The mean specificities of three- and four-phase CT images were 99% and 98%, respectively. The differences between the specificities were not statistically significantly (all p > 0.05). Neither were the mean areas under the ROC curve for four-phase CT images (Az = 0.976) and three-phase CT images (Az = 0.971) statistically significant (p > 0.05). On early arterial phase imaging, 16 HCCs were hyperattenuating and 17 HCCs were isoattenuating. On late arterial phase imaging, 24 HCCs were hyperattenuating and nine HCCs were isoattenuating.

CONCLUSIONS

Additional early arterial phase imaging did not improve the detection of HCC compared with three-phase CT images, including late arterial, portal venous, and delayed phase imaging.

Detection of hepatocellular carcinoma: value of adding delayed phase imaging to dual-phase helical CT

OBJECTIVE

The purpose of our study was to determine the value of adding delayed phase imaging to dual-phase helical CT for the detection of hepatocellular carcinoma.

SUBJECTS AND METHODS

One hundred thirteen patients with 131 hepatocellular carcinomas underwent triple-phase helical CT. The diagnosis was established by pathologic examination after surgical resection in all patients. For triple-phase helical CT, hepatic arterial, portal venous, and delayed phase scanning began 30, 60, and 180 sec, respectively, after the injection of 120 mL of iodinated contrast material. Dual-phase helical CT excluding delayed phase and triple-phase helical CT images were reviewed independently by three radiologists on a segment-by-segment basis. Diagnostic accuracy was assessed using receiver operating characteristic analysis in 330 resected segments. Sensitivities and specificities were calculated. The value of the delayed phase images in the characterization of hepatocellular carcinoma was also assessed.

RESULTS

The diagnostic accuracy of triple-phase helical CT including delayed phase (area under the curve [A(z)], 0.973) was significantly higher than that of dual-phase helical CT (A(z), 0.954). The mean sensitivity of triple-phase CT (89%) was also significantly higher than that of dual-phase CT (86%). The mean specificities of triple-phase CT (99%) and dual-phase CT (99%) were equal. Delayed phase images were helpful in the characterization of hepatocellular carcinoma in 14% of patients.

CONCLUSION

The addition of delayed phase imaging to dual-phase helical CT is valuable for the detection and characterization of hepatocellular carcinoma.

Impact of multidetector CT hepatic arteriography on the planning of chemoembolization treatment of hepatocellular carcinoma

OBJECTIVES

We examined the impact of the increased sensitivity for hypervascular masses of multidetector CT hepatic arteriography on treatment decisions involving selective chemoembolization of hepatocellular carcinomas.

SUBJECTS AND METHODS

Thirty patients were referred for chemoembolization of unresectable hepatocellular carcinoma. Initial selective chemoembolization plans were formulated on the basis of diagnostic biphasic CT or MR imaging. Ultrafast CT hepatic arteriography was performed using a multidetector CT scanner and selective contrast material injection into the hepatic artery. The entire liver was scanned in a single breath-hold of approximately 20 sec with a slice thickness of 1 mm. Lesions and their arterial supplies were identified, and these data were immediately used to formulate a final plan for chemoembolization.

RESULTS

Hypervascular masses were detected in 29 patients. In 16 (53%) of the patients, preprocedural CT or MR imaging underestimated the number of lesions. In nine (30%) of these 16 patients, the additional lesions were detected only on CT hepatic arteriography, not on conventional angiography. CT hepatic arteriography findings had a major impact on planning the way in which chemoembolization treatment was performed. In three of the nine patients, the previously undetected lesions were treated with additional superselective chemoembolization. In the other six patients, chemoembolization was performed less selectively than originally planned.

CONCLUSION

Primarily because of the high sensitivity of multidetector CT hepatic arteriography in revealing small and multifocal hepatomas, findings of this modality frequently alter treatment plans involving selective administration of chemoembolic material.

Value of lipiodol computed tomography and digital subtraction angiography in the era of helical biphasic computed tomography as preoperative assessment of hepatocellular carcinoma

OBJECTIVE

To compare the diagnostic accuracies of Lipiodol computed tomography (CT) and helical biphasic CT as preoperative imaging modalities for hepatocellular carcinoma (HCC).

SUMMARY BACKGROUND DATA

Lipiodol CT after digital subtraction angiography has long been used as a highly sensitive imaging modality for HCC. The recent advent of helical CT has allowed scanning the entire liver during both the arterial and portal venous phase of contrast enhancement.

METHODS

The authors analyzed data from 164 patients who underwent hepatic resection for HCC to calculate the sensitivity and specificity of these modalities. Findings of intraoperative ultrasonography followed by histologic confirmation were set as the gold standard.

RESULTS

Although sensitivity decreased with both modalities as tumors became small and well differentiated, helical CT showed a higher sensitivity than Lipiodol CT in detecting well-differentiated HCC nodules smaller than 2 cm. In contrast, Lipiodol CT was superior to helical CT for the detection of small but moderately to poorly differentiated nodules. The overall sensitivity of helical CT was higher than that of Lipiodol CT. These findings suggest that helical CT is superior in delineating early HCC, whereas Lipiodol CT is specific to the detection of intrahepatic metastases. In terms of specificity, helical CT was superior to Lipiodol CT.

CONCLUSIONS

Helical CT and Lipiodol CT are complementary modalities. At present, helical biphasic CT does not obviate the need for invasive techniques such as angiography and Lipiodol CT as preoperative examinations for HCC.

CT demonstration of the spontaneous regression of a hypervascular lesion in cirrhotic liver

In patients with liver cirrhosis, arterial phase enhancement of nodular lesions on helical-CT is currently considered to be highly predictive of malignancy. We report the spontaneous regression of a hypervascular hepatic nodule in a patient with liver cirrhosis within 7 months demonstrated by helical-CT follow-up. This suggests that tumor angiogenesis known to be an obligatory step for acquisition of malignant properties could regress, and can be demonstrated by helical CT. Radiologists should be aware that CT detection of a hypervascular nodule in a cirrhotic liver is not always predictive of a malignant outcome.

Value of hepatic arterial phase CT versus lipiodol ultrafluid CT in the detection of hepatocellular carcinoma

OBJECTIVE

To evaluate the role of hepatic arterial phase (HAP) spiral computed tomography (CT), as compared with iodized oil (Lipiodol ultrafluid [LUF]) CT for revealing nodular hepatocellular carcinomas (HCC).

METHODS

Twenty-four cirrhotic patients underwent two-phase HCT examination: HAP 25 seconds and portal phase 70 seconds after injection of 1.5 mL/Kg contrast medium. All patients also underwent hepatic angiography and intraarterial infusion of iodized oil; LUF CT was performed 3-4 weeks after infusion. HCT images were compared with LUF CT images for detection of hepatic nodules.

RESULTS

We found no significant difference between the sensitivity of HAP CT and LUF CT for nodules >10 mm, while HAP CT was more sensitive than LUF CT in revealing nodules <10 mm (47 vs. 27, p < 0.001).

CONCLUSIONS

HCT should be considered as the first method for the detection of HCC, whereas LUF CT should be used only for therapy.

Hepatic malignancies

The battle against malignancies of the liver is far from over, although tremendous strides have been made in the past decade, such as improved diagnostic capabilities, safe surgical resection, availability of safe nonsurgical ablative modalities, multimodality therapy, and aggressive approach to recurrent disease. Even after the best attempts at curative treatment, recurrence of primary and secondary malignancies of the liver continues to be the cause of demise for more than 70% of treated patients. The battle continues in the laboratories, where investigations are focused on delineating the pathophysiology of cancer on the molecular and genetic levels and mapping the patterns of cancer emergence and spread. The new millennium holds promise for formulating therapies that may improve disease-free survival for patients with malignancies of the liver.

Nodular hepatocellular carcinoma: variation of tumor conspicuity on single-level dynamic scan and optimization of fixed delay times for two-phase helical CT

PURPOSE

The purpose of this work was to determine the optimal delay times in two-phase helical CT for nodular hepatocellular carcinoma (HCC).

METHOD

Twenty-four patients with nodular HCC (size 2.1-6.7 cm, mean 4.2 cm) were divided into three groups to undergo single-level dynamic CT with 150 ml of contrast material (iodine load of 45 g) at a rate of 3 ml/s. CT acquisition started 10, 30, or 60 s after the injection for each group, respectively, and lasted for 110 or 120 s. The optimal 20 s windows that allowed a tumor-to-liver contrast of >10 HU were determined in the pooled tumor-to-liver contrast curve.

RESULTS

The determined temporal windows were 36-56 and 130-150 s, respectively. However, each window was not appropriate in seven (33%) and five (36%) patients because of the individual variations of the contrast curve.

CONCLUSION

There is no optimal fixed delay time that is appropriate in all individual patients. The best delay times are 36 and at least 130 s with our injection protocol.

Salivary gland tumors: evaluation with two-phase helical CT

PURPOSE

To evaluate two-phase helical computed tomography (CT) in the characterization of salivary gland tumors.

MATERIALS AND METHODS

Sixty-four patients with major salivary gland tumors underwent two-phase helical CT. The histopathologic diagnosis was obtained by means of surgical resection or biopsy in all patients. After the injection of 90 mL of contrast material at a rate of 3 mL/sec, helical CT scans were obtained at early and delayed phases with scanning delays of 30 and 120 seconds, respectively. The attenuation change and enhancement patterns in the tumors were assessed. The attenuation change in the tumor also was assessed quantitatively as the ratio of the CT number (in Hounsfield units) at delayed phase scanning to that at early phase scanning.

RESULTS

There were 35 pleomorphic adenomas, nine Warthin tumors, and 20 malignant tumors. Two-phase helical CT showed increase in attenuation in 30 (86%) pleomorphic adenomas, decrease in eight (89%) Warthin tumors, and increase in 11 (55%) and no change in eight (40%) malignant tumors at delayed phase scanning. A multinodular enhancement pattern was found in only 12 (34%) pleomorphic adenomas. The ratio of CT numbers was significantly different between Warthin tumors and pleomorphic adenomas and between Warthin tumors and malignant tumors.

CONCLUSION

The analysis of enhancement patterns by using two-phase helical CT will be helpful in the differential diagnosis of salivary gland tumors.

Hepatocellular carcinoma treated with chemoembolization: assessment with contrast-enhanced doppler ultrasonography

PURPOSE

To report our preliminary experience concerning the use of Doppler ultrasonography (DUS) techniques after intravenous injection of the galactose-based contrast agent Levovist in the assessment of hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolization (TACE). The sonographic findings are correlated with those obtained using iodized oil (Lipiodol) helical computed tomography (CT).

METHODS

For 7 months we studied 28 patients with cirrhosis and HCC (a total of 43 nodules) who had undergone TACE between 18 and 30 days previously. The lesions were investigated with color Doppler ultrasonography (CDUS) and power Doppler ultrasonography (PDUS), before and after infusion of the echo-contrast agent (300 mg/ml, maximum 1 injection for each nodule, administered at constant velocity within 60-90 sec), and with helical Lipiodol-CT (0-7 days after DUS). In the retrospective analysis, special attention was given to the Doppler signals related to pulsatile intra- and perinodular flow and to the detection of new vessels after contrast agent injection. The signal intensity was graded as 0 (absent), 1 (low), 2 (medium), or 3 (high), while its distribution was classified as peripheral, central, or diffuse. Oily agent retention on CT scans was assessed as 0 (absent), I (<10%), II (<50%), III (>50%), or IV (homogeneous). These scores were awarded separately, without knowledge of the other judgments.

RESULTS

An hepatic global echo-enhancing effect was identified in all cases and always lasted long enough to allow an accurate analysis of all parenchymal lesions (at least 8 min). The signal scores could be evaluated in 39 of 43 HCCs, as follows: basal CDUS: grade 0 in 17 lesions, grade 1 in 16, grade 2 in 6; contrast-enhanced CDUS: grade 0 in 12 lesions, grade 1 in 10, grade 2 in 14, grade 3 in 3; basal PDUS: grade 0 in 15 lesions, grade 1 in 13, grade 2 in 9, grade 3 in 2; contrast-enhanced PDUS: grade 0 in 11 lesions, grade 1 in 9, grade 2 in 15, grade 3 in 6. Lipiodol-CT scoring was: grade 0 in 1 lesion, grade I in 7, grade II in 11, grade III in 9, grade IV in 11. In all but one nodule the difference between CDUS and PDUS scores, compared both with each other and with nonenhanced and contrast-enhanced examinations, was never greater than one grade.

CONCLUSIONS

Contrast-enhanced DUS is a simple and fast procedure allowing a valuable, constant echo-enhancing effect of sufficient duration. DUS techniques, especially contrast-enhanced PDUS, offer an effective and realistic analysis of HCC nodules treated with TACE and show more evident agreement with Lipiodol-CT findings than baseline studies.