Biomedical subjects

Seong Hyun Kim

Publications and source records attributed to Seong Hyun Kim.

16 recordsLinked to original sources

PubMed2007

Sclerosing hepatic carcinoma: helical CT features.

BACKGROUND: The purpose of this study was to describe our experience, particularly for CT features, with four patients who had pathologically proven sclerosing hepatic carcinoma that mimicked other malignant hepatic tumors with abundant fibrosis at CT. METHODS: Over a 10-year period, we collected four patients with surgically proven sclerosing hepatic carcinoma. All patients were men (age range, 49-63 years; mean, 56 years). Three-phase helical CT images were obtained in all patients, and their CT features were correlated with pathologic findings. RESULTS: The tumor size ranged from 2.7 to 11 cm (mean, 7.2 cm). The tumors were manifested as a hypoattenuating mass with peripheral, rim enhancement at hepatic arterial phase, followed by centripetal enhancement progressively during portal venous and equilibrium phases. Histopathologically, the tumors showed features intermediate between hepatocellular carcinoma and cholangiocarcinoma with abundant fibrosis and surrounding liver had no liver cirrhosis. CONCLUSION: As described above, the CT features of sclerosing hepatic carcinoma may be similar to other malignant hepatic tumors with abundant fibrosis. Although sclerosing hepatic carcinoma is extremely rare, the radiologists should recognize that this tumor may be one of the malignant hepatic tumors with abundant fibrosis, especially in the non-cirrhotic liver.

Biopsy↗

PubMed2006

Changes in signal-to-noise ratios and contrast-to-noise ratios of hypervascular hepatocellular carcinomas on ferucarbotran-enhanced dynamic MR imaging.

PURPOSE: To verify changes in the signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) of hypervascular hepatocellular carcinomas (HCCs) on ferucarbotran-enhanced dynamic T1-weighted MR imaging. MATERIALS AND METHODS: Fifty-two patients with 61 hypervascular HCCs underwent ferucarbotran-enhanced dynamic MR imaging, and then hepatic resection. Hypervascular HCCs were identified when definite enhancement was noted during the arterial dominant phase of three-phase MDCT. Dynamic MR Images with T1-weighted fast multiplanar spoiled gradient-recalled echo sequence (TR200/TE4.2) were obtained before and 20 s, and 1, 3, 5, and 10 min, after bolus injection of ferucarbotran. We estimated the signal intensities of tumors and livers, and calculated the SNRs and CNRs of the tumors. RESULTS: On ferucarbotran-enhanced dynamic MR imaging, SNR measurements showed a fluctuating pattern, namely, an increase in SNR followed by a decrease and a subsequent increase (or a decrease in SNR followed by a increase and a subsequent decrease) in 50 (82.0%) of 61 tumors, a single-peak SNR pattern (highest SNR on 20 s, 1, 3, or 5 min delayed images followed by a decrease) in seven (11.5%), and a decrease in SNR followed by an increase in four (6.6%). Maximum absolute CNRs with positive value were noted on 10 min delayed images in 41 (67.2%) tumors, and maximum absolute CNRs with negative value were observed on 20 s delayed images in 12 (19.7%) and on 1 min delayed images in eight (13.1%). CONCLUSION: Despite showing various SNR and CNR changes, the majority of hypervascular HCCs demonstrated a fluctuating SNR pattern on ferucarbotran-enhanced dynamic MR imaging and a highest CNR on 10 min delayed image, which differed from the classic enhancement pattern on multiphasic CT.

Adult↗

PubMed2006

Detection of hepatic VX2 carcinomas with ferucarbotran-enhanced magnetic resonance imaging in rabbits: Comparison of nine pulse sequences.

OBJECTIVE: To compare the diagnostic performance of a variety of magnetic resonance imaging (MRI) sequences, in order to identify the most effective ferucarbotran-enhanced sequence for the detection of multiple small hepatic VX2 carcinomas in rabbits. METHODS: Fifteen rabbits with experimentally induced 135 VX2 carcinomas in the liver underwent ferucarbotran-enhanced MRI using the following nine pulse sequences: a fat-suppressed fast spin-echo (FSE) sequence with two echo times (TE) (proton density- and T2-weighted images), four different T2*-weighted fast multiplanar GRASS (gradient-recalled acquisition in the steady state) (FMPGR) with the combination of three TEs (9, 12, 15 ms, respectively) and two flip angles (20 degrees , 80 degrees, respectively), T2*-weighted fast multiplanar spoiled GRASS (FMPSPGR), T1-weighted FMPSPGR, and dynamic T1-weighted FMPSPGR. All images were reviewed by three radiologists with quantitative and qualitative analysis. RESULTS: Tumor-to-liver contrast-to-noise ratio of the proton density-weighted FSE sequence was significantly higher than those of the others (p<0.05). The lesion conspicuities of proton density- and T2-weighted FSE and T2*-weighted FMPGR (TE/flip angle, 9/20 degrees and 12/20 degrees ) images were better and the image artifacts of T2*-weighted FMPGR (TE/flip angle, 15/20 degrees and 12/80 degrees ) and T2*-weighted FMPSPGR images were more prominent than those of the others (p<0.05). The lesion detection in T2- and proton density-weighted FSE and T2*-weighted FMPGR (TE/flip angle, 12/20 degrees ) images were superior to those of the others and for the detection of very small hepatic tumors of less than 5 mm, the sensitivities of these sequences were less than 30%. CONCLUSION: Ferucarbotran-enhanced T2- and proton density-weighted FSE and T2*-weighed FMPGR (TE/flip angle, 12/20 degrees ) images were found to be the most effective pulse sequences for the detection of multiple small hepatic VX2 carcinomas but these sequences were limited in the detection of very small hepatic tumors of less than 5 mm in size.

Animals↗

PubMed2006

Recent variceal bleeding: Doppler US hepatic vein waveform in assessment of severity of portal hypertension and vasoactive drug response.

PURPOSE: To prospectively evaluate both the correlation between abnormal Doppler ultrasonography (US) hepatic vein waveforms and the hepatic venous pressure gradient (HVPG) and the response to drug treatment in patients with cirrhosis. MATERIALS AND METHODS: Ethics committee approval and informed consent of patients and control subjects were obtained. In 78 patients with cirrhosis (70 men, eight women; mean age, 49.4 years +/- 9.7 [standard deviation]) and a history of variceal bleeding, both the hepatic vein waveform--as measured with Doppler US--and the HVPG were measured, and the relationship between them was analyzed. Hepatic vein Doppler waveforms were classified as triphasic, biphasic, or monophasic. Severe portal hypertension was defined as an HVPG of more than 15 mm Hg. In a subgroup of 21 patients, changes in hepatic vein waveform and HVPG were evaluated after intravenous administration of 2 mg of terlipressin. Statistical analyses were performed with Spearman rank correlation, logistic regression analysis, and cross tabulation. RESULTS: Abnormal hepatic vein waveforms were seen in 72 patients (92%). Forty-four patients (56%) had biphasic waveforms, 28 (36%) had monophasic waveforms, and six (8%) had triphasic waveforms. A positive correlation was found between the extent of abnormalities in hepatic vein waveforms and the increase in HVPG (P < .05). Monophasic waveforms were associated with severe portal hypertension, with a sensitivity of 74% and a specificity of 95%. Twenty patients in the terlipressin subgroup had abnormal baseline waveforms; the baseline waveform improved in 18 patients in association with the HVPG reduction after injection of terlipressin. CONCLUSION: Doppler US hepatic vein waveform assessment is useful in the noninvasive evaluation of the severity of portal hypertension and the response to vasoactive drugs in patients with portal hypertension and variceal bleeding.

Antihypertensive Agents↗

PubMed2006

Percutaneous radiofrequency ablation of hepatocellular carcinoma: effect of histologic grade on therapeutic results.

OBJECTIVE: The purpose of our study was to assess the therapeutic results of radiofrequency ablation of hepatocellular carcinoma (HCC) based on the histologic grades of the tumors. SUBJECTS AND METHODS: Between April 1999 and December 2003, 95 patients with nodular HCC were treated with percutaneous radiofrequency ablation. All tumors were histologically proven by sonography-guided percutaneous biopsy and were classified as Edmondson-Steiner grade I HCC (n = 38) (mean, 2.3 cm) (group 1), grade II HCC (n = 50) (mean, 2.4 cm) (group 2), or grade III HCC (n = 7) (mean, 2.8 cm) (group 3). All patients underwent contrast-enhanced three-phase helical CT examination before and after radiofrequency ablation. After retrospective review of the medical records and follow-up CT examinations, the rates of technique effectiveness, local tumor progression, cumulative survival, and cancer-free survival using a Kaplan-Meier method were calculated and compared among the groups. RESULTS: Technique effectiveness rates in groups 1, 2, and 3 were 87% (27/31), 71% (30/42), and 43% (3/7), respectively, with statistical significance (p = 0.032). Local tumor progression rates in groups 1, 2, and 3 were 16% (5/31), 36% (15/42), and 71% (5/7), respectively, with statistical significance (p = 0.013). Five-year cumulative survival rates in groups 1, 2, and 3 were 71%, 44%, and 43%, respectively, with no statistical significance (p > 0.05). Four-year cancer-free survival rates in groups 1, 2, and 3 were 39%, 10%, and 0%, respectively (p < 0.05 for groups 1 vs 2; p > 0.05 for groups 1 vs 3 and groups 2 vs 3). CONCLUSION: The histologic grade of HCC is an important factor influencing therapeutic results with survival after radiofrequency ablation.

Carcinoma, Hepatocellular↗

PubMed2005

Ferucarbotran-enhanced MRI versus triple-phase MDCT for the preoperative detection of hepatocellular carcinoma.

OBJECTIVE: We compared ferucarbotran-enhanced MRI with triple-phase MDCT for the preoperative detection of hepatocellular carcinoma. SUBJECTS AND METHODS: Seventy-three consecutive patients with 121 hepatocellular carcinomas underwent ferucarbotran-enhanced MRI, including a dynamic study, and triple-phase MDCT before hepatic resection. The diagnosis of hepatocellular carcinoma was confirmed in all patients by means of pathologic examination after surgical resection. Three experienced radiologists independently reviewed the MR and CT images on a segment-by-segment basis. The accuracy of these techniques for the detection of hepatocellular carcinoma was assessed by conducting a receiver operating characteristic (ROC) analysis of the observations of 88 resected hepatic segments with at least one hepatocellular carcinoma each and 121 resected hepatic segments without hepatocellular carcinoma. RESULTS: The mean values of the area under the ROC curve (A(z)) for ferucarbotran-enhanced MRI and triple-phase MDCT for all observers were 0.947 and 0.949, respectively; the difference between these two values was not statistically significant (p = 0.799). The mean sensitivities of MRI and triple-phase MDCT were 90.2% and 91.3%, respectively, and their mean specificities were 97.0% and 95.3%, respectively. The differences in the mean sensitivities and specificities of these two imaging techniques were not statistically significant (p > 0.05 in each case). CONCLUSION: Ferucarbotran-enhanced MRI seems to be as accurate as triple-phase MDCT for the preoperative detection of hepatocellular carcinoma.

Adult↗

PubMed2005

Endovascular treatment of wide-necked aneurysms by using two microcatheters: techniques and outcomes in 25 patients.

BACKGROUND AND PURPOSE: The endovascular occlusion of aneurysms with unfavorable configurations such as a broad neck and an important branch from the fundus remains a technical challenge. The purpose of this study was to evaluate the radiologic and clinical results of complicated aneurysm treatment by using two microcatheters. METHODS: Twenty-five aneurysms in 25 patients were treated by using two microcatheters, from August 2001 to February 2004. Fourteen patients presented with a subarachnoid hemorrhage (SAH) and 11 had unruptured aneurysms. The aneurysms were of the basilar top (7), middle cerebral artery bifurcation (4), posterior communicating artery (4), anterior communicating artery (3), superior cerebellar artery (2), ophthalmic artery (2), and one aneurysm of each of cavernous internal carotid artery (ICA), dorsal ICA, and midbasilar artery. In 16 aneurysms (64%), the width of the aneurysm was the same or longer than the height. In 19 (76%), important branches arose from the aneurysm base, and some were even incorporated with the aneurysm fundus. The mean dome (height)-to-neck ratio was 1.23 +/- 0.37 (range, 0.65-2.33), and this was greater than or equal to 1.0 in 19 aneurysms (76%). RESULTS: All aneurysms were successfully embolized. Immediate postembolization angiography showed no residual contrast filling in eight aneurysms (32%), and some residual contrast filling in 16. The aneurysm remnants, however, were intentionally left to preserve important branches in 12 of the 16 aneurysms with incomplete occlusion. Two complications occurred, including one thromboembolic and one coil protrusion, but they were successfully resolved and produced no clinical symptoms. All patients except one showed excellent clinical outcomes. One patient revealed moderate cognitive dysfunction. During the follow-up period, no new bleeding occurred. CONCLUSION: Our experience with 25 cerebral aneurysm patients shows that the technique of using two microcatheters is feasible and safe for coil embolization of aneurysms with unfavorable configurations. Although the lack of angiographic follow-up prevents us from drawing conclusions about its effectiveness as compared with other techniques such as stent placement and balloon-neck protection, we believe that this technique offers a reliable alternative for endovascular therapy of complicated aneurysms.

Adult↗

PubMed2004

Depiction and local staging of rectal tumors: comparison of transrectal US before and after water instillation.

PURPOSE: To determine whether transrectal ultrasonography (US) with intrarectal water instillation can improve the depiction and accuracy of US in local staging of rectal tumors. MATERIALS AND METHODS: Between October 1999 and February 2002, 63 patients (mean age, 56 years; age range, 23-91 years) with 63 rectal tumors were evaluated with transrectal US before and after intrarectal water instillation. Transrectal US examinations were performed with a 7-10-MHz radial transducer. Immediately after the first transrectal US examination, the rectal lumen was filled with 50-150 mL of degassed water, and a second US examination was performed. All patients underwent surgery within 1 month after transrectal US. Depiction of the tumor was compared between the two methods. The McNemar test was used to compare the accuracy between the two techniques in local staging of the tumor by using pathologic findings in the resected specimen as the standard. RESULTS: The tumors ranged from 0.5 to 8.0 cm (mean, 2.8 cm) as measured at pathologic evaluation. All 63 tumors were clearly depicted at transrectal US after water instillation, while only 42 (67%) of the tumors were depicted at transrectal US before water instillation. In the 42 tumors clearly depicted at transrectal US examinations both before and after water instillation, the accuracy of transrectal US in local tumor staging was significantly higher after water instillation (85.7% [36 of 42]) than before water instillation (57.1% [24 of 42]; P <.001). CONCLUSION: Water instillation during transrectal US examination of rectal tumors improves the depiction and local staging of the tumors.

Adult↗

PubMed2004

Therapeutic efficacy and safety of percutaneous radiofrequency ablation of hepatocellular carcinoma abutting the gastrointestinal tract.

OBJECTIVE: The purpose of this study was to evaluate the therapeutic efficacy and safety of percutaneous radiofrequency ablation in the treatment of hepatocellular carcinomas abutting the gastrointestinal tract. MATERIALS AND METHODS: Forty-one patients with hepatocellular carcinomas abutting the gastrointestinal tract underwent sonographically guided percutaneous radiofrequency ablation. Forty-one tumors (1.2-4.3 cm in maximum diameter) had parts 5 mm or greater (or at least one quarter of their circumferences) abutting the stomach in 23 patients and the colon in 18 patients. Thirty tumors were ablated with internally cooled electrodes and 11 with multitined expandable electrodes. All patients were followed up for at least 1 year after ablation. Therapeutic efficacy and safety were evaluated with follow-up sonography and multiphase helical CT. RESULTS: At 1-month follow-up CT, three (7%) of the 41 tumors showed residual unablated tumor in the ablation zone. Of the remaining 38 hepatocellular carcinomas (93%) with no evidence of residual unablated tumor, four (11%) showed local tumor progression in the ablation zones on subsequent follow-up CT. We observed one major complication-a small perihepatic abscess-that needed specific treatment. CONCLUSION: Percutaneous radiofrequency ablation is an effective and safe technique for treating hepatocellular carcinomas abutting the gastrointestinal tract.

Adult↗

PubMed2004

Changes in bile ducts after radiofrequency ablation of hepatocellular carcinoma: frequency and clinical significance.

OBJECTIVE: The purpose of our study was to determine the frequency of bile duct changes after radiofrequency ablation for hepatocellular carcinoma and to evaluate their clinical significance. MATERIALS AND METHODS: Between April 1999 and August 2003, 389 patients with 521 hepatocellular carcinomas underwent a total of 571 sessions of radiofrequency ablation. The maximum dimension of the tumors measured on sonography was 2.4 +/- 0.9 cm (mean +/- SD) (range, 0.5-5.0 cm). The frequency and type of bile duct changes resulting from radiofrequency ablation, the time interval between radiofrequency ablation and the first appearance of bile duct changes, and the serial changes at follow-up CT were analyzed. Complications related to bile duct changes were also evaluated by reviewing medical records and CT scans. RESULTS: Bile duct changes occurred in 69 (12%) of 571 sessions and 66 (17%) of 389 patients. Bile duct changes seen on CT included mild dilatation of upstream bile ducts surrounding the ablation zone in 57 patients (82.6%), biloma in the ablation zone in four patients (5.8%), and both in eight patients (11.6%). The mean time interval between radiofrequency ablation and the initial appearance of bile duct change was 1.6 months (range, immediate-9 months). Most (87%) of the 69 patients with bile duct changes showed no progression on follow-up CT, and only nine (13%) had slight progression. All patients but one, in whom cholangitis developed, had no major complications requiring specific treatment during the follow-up period. CONCLUSION: Although bile duct changes were frequent after the radiofrequency ablation of hepatocellular carcinoma, most were of no clinical significance, and major complications requiring additional treatment were rare.

Adult↗

PubMed2004

Evaluation of hepatic focal nodular hyperplasia with contrast-enhanced gray scale harmonic sonography: initial experience.

OBJECTIVE: To assess the potential of contrast-enhanced gray scale harmonic sonography in the evaluation of the typical vascular and enhancement patterns of hepatic focal nodular hyperplasia. METHODS: Thirteen patients with 13 lesions of hepatic focal nodular hyperplasia underwent contrast-enhanced gray scale harmonic sonography. After the injection of a microbubble contrast agent (SH U 508A), gray scale harmonic sonographic studies using a Coded Harmonic Angio technique were performed with a combination of a period of continuous scanning to assess the vascular pattern (vascular imaging) and interval delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed by consensus of 2 experienced radiologists. RESULTS: In 12 (92%) of 13 lesions, vascular imaging during the arterial phase showed central arteries of a spoked wheel pattern, whereas the remaining lesion had stippled vascularity. On acoustic emission imaging, 11 (85%) of 13 lesions were hyperechoic during the early phase, and the remaining 2 (15%) were isoechoic compared with surrounding parenchyma. Ten (77%) of 13 lesions remained either hyperechoic (5 of 13) or isoechoic (5 of 13) during the delay phase, whereas the remaining 3 lesions (23%) were hypoechoic. CONCLUSIONS: Contrast-enhanced gray scale harmonic sonography showed the typical vascularity of a spoked wheel pattern during the vascular phase and persistent enhancement on serial acoustic emission imaging in most cases of hepatic focal nodular hyperplasia, and thereby it can be a promising technique in noninvasive diagnosis of this entity.

Adolescent↗

PubMed2003

Early assessment of the therapeutic response to radio frequency ablation for hepatocellular carcinoma: utility of gray scale harmonic ultrasonography with a microbubble contrast agent.

OBJECTIVE: To evaluate the utility of gray scale harmonic ultrasonography with a microbubble contrast agent in the early assessment of the therapeutic response to radio frequency ablation for hepatocellular carcinoma. METHODS: Seventy-five patients with 81 nodular hepatocellular carcinomas (1.3-4.8 cm) treated with percutaneous radio frequency ablation were evaluated with contrast-enhanced gray scale harmonic ultrasonography after intravenous bolus injection of a galactose-based microbubble contrast agent. The vascularity within the ablation zones was evaluated with a continuous scan for 3 to 5 seconds between 15 and 30 seconds after initiation of contrast agent injection. To evaluate the perfusion of the ablation zones, intermittent stimulated acoustic emission imaging was performed with a rapid sweeping technique from the end of the continuous scan. All patients underwent follow-up 3-phase helical computed tomography at 1 month after radio frequency ablation and were followed for at least 1 year. The results of contrast-enhanced ultrasonography were compared with those of follow-up computed tomography in terms of the presence or absence of residual unablated tumors. RESULTS: In 10 (12%) of the 81 treated hepatocellular carcinomas, contrast-enhanced ultrasonography showed either nodular or crescentic enhancing foci at the margins of ablation zones, suggesting residual unablated tumors. Contrast-enhanced computed tomography obtained 1 month after radio frequency ablation confirmed the residual unablated tumors in the same 10 lesions. Diagnostic agreement between 1-month follow-up computed tomography and contrast-enhanced ultrasonography was achieved in all 81 cases (100%). CONCLUSIONS: Contrast-enhanced gray scale harmonic ultrasonography can be a reliable alternative to contrast-enhanced computed tomography in the early assessment of the therapeutic response to radio frequency ablation for hepatocellular carcinoma.

Adult↗

PubMed2002

The C sign.

Explore the source record for details and available documents.

Ankle↗

PubMedDate not supplied

Intraductal papillary mucinous tumor of the bile ducts.

Papillary tumors of the bile ducts are intraductal tumors with numerous minute frondlike papillary projections. Some intraductal papillary tumors of the bile ducts produce a large amount of mucin that disturbs bile flow and causes severe biliary dilatation. In the presence of a tumor of this subgroup, the entire biliary tree is dilated; segmental or lobar bile ducts are dilated disproportionately, and aneurysmal dilatation may occur. Mucin is depicted at cholangiography as multiple elongated or cordlike filling defects, and the tumor is depicted on cross-sectional images as a castlike, polypoid, or fungating mass in the dilated biliary tree. Based on these characteristic imaging features-dilatation, mucin, and tumor-correct diagnosis of intraductal papillary mucinous tumor of the bile ducts may be made.

Adenocarcinoma, Papillary↗

PubMedDate not supplied

Overlapping ablation using a coaxial radiofrequency electrode and multiple cannulae system: experimental study in ex-vivo bovine liver.

OBJECTIVE: To assess the sizes and configurations of thermal zones after overlapping ablations using a coaxial radiofrequency (RF) electrode and multiple cannulae in ex-vivo bovine liver. MATERIALS AND METHODS: For ablation procedures, a coaxial RF electrode and introducer set was used. Employing real-time ultrasound guidance and overlapping techniques in explanted, fresh bovine liver, we created five kinds of thermal zones with one (n=10), two (n=8), four (n=3), and six ablation spheres (n=3). Following ablation, MR images were obtained and the dimensions of all thermal zones were measured on the longitudinal or transverse section of specimens. The shape of the composite ablation zones was evaluated using three-dimensional MR image reconstruction. RESULTS: At gross pathologic examination of ten single-ablation zones (spheres), the long-axis (transverse) and short-axis lengths of zones ranged from 3.7 to 4.4 (mean, 4.1) cm and from 3.5 to 4.0 (mean, 3.7) cm, respectively. The long-axis (transverse) and short-axis lengths of double-ablation zones (cylinders) with 23% overlap ranged from 7.0 to 7.7 (mean, 7.3) cm and from 3.0 to 3.9 (mean, 3.5) cm, respectively; those with 58% overlap ranged from 6.0 to 6.4 (mean, 6.2) cm and from 3.8 to 4.6 (mean, 4.3) cm, respectively. The long-axis (diagonal) and short-axis lengths on a transverse section of four-ablation zones (cakes) ranged from 8.5 to 9.7 (mean, 9.1) cm and from 3.0 to 4.1 (mean, 3.7) cm, respectively. Gross pathologic examination of three composite six-ablation zones (spheres) showed that the long-axis (diagonal) and short-axis lengths of zones ranged from 9.0 to 9.9 (mean, 9.4) cm and from 6.8 to 7.5 (mean, 7.2) cm, respectively. T2-weighted MR images depicted low-signal thermal zones containing multiple curvilinear and spotty regions of hyperintensity. CONCLUSION: Using a coaxial RF electrode and multiple cannulae, together with ultrasound guidance and precise overlapping ablation techniques, we successfully created predictable thermal zones in ex-vivo bovine liver.

Animals↗

PubMedDate not supplied

Focal hepatic lesions: evaluation with contrast-enhanced gray-scale harmonic US.

OBJECTIVE: To determine the findings of various focal hepatic lesions at contrast-enhanced gray-scale ultrasound (US) using a coded harmonic angio (CHA) technique and emphasizing lesion characterization. MATERIALS AND METHODS: The study involved 95 patients with 105 focal hepatic lesions, namely 51 hepatocellular carcinomas (HCCs), 22 metastases, 22 hemangiomas, four cases of focal nodular hyperplasia (FNH), and six nontumorous nodules. After the injection of a microbubble contrast agent (SH U 508A), gray-scale harmonic US studies using a CHA technique were performed with a combination of continuous scanning to assess the intratumoral vasculature (vascular imaging) and interval-delay scanning to determine the sequential enhancement pattern (acoustic emission imaging). Each imaging pattern was categorized and analyzed. RESULTS: At vascular imaging, 69% of HCCs (35/51) showed irregular branching vessels, while in 91% of metastases (20/22) a peripherally stippled pattern was observed. Intratumoral vessels were absent in 95% of hemangiomas (21/22) and all nontumorous lesions (6/6), while in 75% of FNHs (3/4) a spoke-wheel pattern was evident. At acoustic emission imaging, 71% of HCCs (36/51) showed heterogeneous enhancement and 86% (19/22) of metastases showed rim- or flame-like peripheral enhancement during the early phase, with washout occurring in all HCCs and metastases (100%, 73/73) during the late phase. In hemangiomas, enhancement was either peripheral and nodular (19/22, 86%) or persistent and homogeneous (3/22, 14%), and 75% of FNHs (3/4) became isoechoic during the late phase. CONCLUSION: At contrast-enhanced gray-scale US using a CHA technique, a period of continuous scanning depicted the intratumoral vasculature, and interval-delay scanning demonstrated the sequential enhancement pattern. The characteristic findings of various focal hepatic lesions were thus determined.

Carcinoma, Hepatocellular↗