Late Vascular Phase Research Articles

A Comparative Study of SonoVue and Sonazoid for Contrast-Enhanced Ultrasound CT/MRI Fusion Guidance During Radiofrequency Ablation of Poorly Visualized Hepatic Malignancies: A Prospective Intra-Individual Analysis

PurposeThis study aimed to evaluate the effectiveness of two contrast agents, SonoVue (SV) and Sonazoid (SZ), by comparing them intra-individually in contrast-enhanced ultrasound (CEUS)-CT/MRI fusion imaging (FI) to improve the visibility of inconspicuous liver malignancies on B-mode sonography for guiding percutaneous radiofrequency ablation (RFA). Additionally, the radiologists' preference between SonoVue- CT/MRI FI (SV-FI) and Sonazoid-CT/MRI FI (SZ-FI) was determined. MethodsThis prospective study enrolled 23 patients with inconspicuous hepatic malignancies (≤ 3 cm) on B-mode US who underwent both SV-FI and SZ-FI for RFA guidance. The patients underwent real-time CEUS FI with CT/MRI on the same day, utilizing both SV and SZ with at least 15-min intervals. Tumor visibility and radiologists' preferences were assessed and graded using a 4-point scale during the dynamic phases of both SV-FI and SZ-FI and the Kupffer phase of SZ-FI. ResultsThe tumor visibility scores obtained from CEUS-CT/MRI FI were significantly better than those obtained from US-FI. Indeed, SV-FI and SZ-FI demonstrated comparable visibility scores when corresponding phases were compared (p > 0.05). However, the Kupffer phase images of SZ-FI displayed superior visibility scores (3.70 ± 0.56 vs. 2.96 ± 0.88; p = 0.002) than the late vascular phase images of SV-FI. The radiologists favored SZ-FI in many cases, exhibiting moderate inter-observer agreement (Kappa value = 0.587; 95% CI, 0.403–0.772). ConclusionAlthough CEUS-CT/MRI FI with either SV or SZ substantially improved the visibility of inconspicuous tumors on US-CT/MRI FI, radiologists preferred SZ to SV to guide the RFA procedure.

WFUMB Review Paper. Incidental Findings in Otherwise Healthy Subjects, How to Manage: Liver.

An incidental focal liver lesion (IFLL) is defined as a hepatic lesion identified in a patient imaged for an unrelated reason. They are frequently encountered in daily practice, sometimes leading to unnecessary, invasive and potentially harmful follow-up investigations. The clinical presentation and the imaging aspects play an important role in deciding if, and what further evaluation, is needed. In low-risk patients (i.e., without a history of malignant or chronic liver disease or related symptoms), especially in those younger than 40 years old, more than 95% of IFLLs are likely benign. Shear Wave liver Elastography (SWE) of the surrounding liver parenchyma should be considered to exclude liver cirrhosis and for further risk stratification. If an IFLL in a low-risk patient has a typical appearance on B-mode ultrasound of a benign lesion (e.g., simple cyst, calcification, focal fatty change, typical hemangioma), no further imaging is needed. Contrast-Enhanced Ultrasound (CEUS) should be considered as the first-line contrast imaging modality to differentiate benign from malignant IFLLs, since it has a similar accuracy to contrast-enhanced (CE)-MRI. On CEUS, hypoenhancement of a lesion in the late vascular phase is characteristic for malignancy. CE-CT should be avoided for characterizing probable benign FLL and reserved for staging once a lesion is proven malignant. In high-risk patients (i.e., with chronic liver disease or an oncological history), each IFLL should initially be considered as potentially malignant, and every effort should be made to confirm or exclude malignancy. US-guided biopsy should be considered in those with unresectable malignant lesions, particularly if the diagnosis remains unclear, or when a specific tissue diagnosis is needed.

Three cases of histologically proven hepatic epithelioid hemangioendothelioma evaluated using a second-generation microbubble contrast medium in ultrasonography: case reports

BackgroundHepatic epithelioid hemangioendothelioma (HEH) is rare; it is reported in < 1 person in 1,000,000 individuals. For accurate diagnosis, information regarding multiple graphic modalities in HEH is required. However, there is very little information concerning Sonazoid® contrast enhanced ultrasonography (CEUS) in HEH.Case presentationThe present report describes the histologically proven three HEH cases evaluated using Sonazoid® CEUS. Case 1 was a 33-year-old female patient with no relevant past medical history, who experienced right upper quadrant pain. Conventional abdominal US revealed multiple low echoic liver nodules with vague borderlines. In CEUS, the vascularity of the nodules was similar to that seen in the neighboring normal liver. Later in the portal venous and late phases (PVLP) and post vascular phase, washout of Sonazoid® was detected in the nodules. Case 2 was a 93-year-old female patient with a previous medical history including operations for breast cancer and ovary cancer in her 50’s. Conventional abdominal US revealed multiple low echoic nodules, some of which contained cystic lesions. In the early vascular phase of CEUS, nodules excluding the central anechoic regions were enhanced from peripheral sites. Although the enhancement inside the nodules persisted in both the PVLP and post vascular phase, anechoic areas in the center of some nodules were not enhanced at all. Case 3 was a 39-year-old male patient presented with right upper-quadrant pain, without any relevant past medical history. Conventional abdominal US revealed multiple low echoic liver nodules. In the early vascular phase of CEUS, nodules were gradually enhanced from the peripheral sites as ringed enhancement. Sonazoid®was washed out from the nodules in the PVLP and post vascular phase.ConclusionsThe most important feature was peripheral enhancement in the early vascular phase. In case 2, the enhancement of the parenchyma of liver nodules persisted even in the PVLP; indicating the lower degree of malignant potential than others. Actually, the tumors did not extend without any treatment in case 2. Since case 2 is the first case report of HEH with cystic lesions, in patients with liver nodules including cystic lesions, HEH is a potential diagnosis.

The imaging features in ultrasonography of cholangiolocarcinoma: correlation with pathological findings.

Background: Cholangiolocellular carcinoma (CoCC) is rare primary liver cancer and currently considered to originate from hepatic progenitor cells. The purpose of this study was to evaluate the imaging features in ultrasonography of cholangiolocellular carcinoma of the liver. Methods: Six cases of surgically resected cases of CoCC from 2 institutions were retrospectively evaluated. All of the six patients underwent contrast-enhanced ultrasonography (CEUS), dynamic CT, Gd-EOB-DTPA MRI and angio-CT including CT during arterioportography (CTAP) and CT during hepatic arteriography (CTHA). Histological evaluation was also performed and was correlated with imaging findings. Results: In the early vascular phase of CEUS, the lesions presented diffuse and homogeneous enhancement in 2 cases with less than 2cm in tumor diameter, but in 4 cases with lager than 2cm, the lesions presented heterogeneous enhancement. From the late vascular phase to Kupffer phase, the continued existence of portal veins or tiny spots of portal flow was identified in the tumors. This feature, portal venous penetration within the tumor, was also observed in Angio CT, but not observed in dynamic CT and Gd-EOB-DTPA MRI. Conclusion: The absence of a fibrous capsule, the absence of tumor necrosis and the presence of portal venous penetration within the tumor also appear to be characteristic features in CEUS. But it may be some difference in the enhancement pattern in vascular phase with tumor size. CEUS is considered to be useful in the diagnosis of CoCC.

The imaging features in ultrasonography of cholangiolocarcinoma: correlation with pathological findings

Background: Cholangiolocellular carcinoma (CoCC) is rare primary liver cancer and currently considered to originate from hepatic progenitor cells. The purpose of this study was to evaluate the imaging features in ultrasonography of cholangiolocellular carcinoma of the liver. Methods: Six cases of surgically resected cases of CoCC from 2 institutions were retrospectively evaluated. All of the six patients underwent contrast-enhanced ultrasonography (CEUS), dynamic CT, Gd-EOB-DTPA MRI and angio-CT including CT during arterioportography (CTAP) and CT during hepatic arteriography (CTHA). Histological evaluation was also performed and was correlated with imaging findings. Results: In the early vascular phase of CEUS, the lesions presented diffuse and homogeneous enhancement in 2 cases with less than 2cm in tumor diameter, but in 4 cases with lager than 2cm, the lesions presented heterogeneous enhancement. From the late vascular phase to Kupffer phase, the continued existence of portal veins or tiny spots of portal flow was identified in the tumors. This feature, portal venous penetration within the tumor, was also observed in Angio CT, but not observed in dynamic CT and Gd-EOB-DTPA MRI. Conclusion: The absence of a fibrous capsule, the absence of tumor necrosis and the presence of portal venous penetration within the tumor also appear to be characteristic features in CEUS. But it may be some difference in the enhancement pattern in vascular phase with tumor size. CEUS is considered to be useful in the diagnosis of CoCC.

Contrast-Enhanced Ultrasonography for Characterization of Focal Splenic Lesions in Dogs

Contrast-enhanced ultrasonography with perflubutane microbubbles improves the diagnostic accuracy to differentiate benign and malignant focal liver lesions in dogs. Perflubutane microbubbles-enhanced ultrasonography is useful for differentiation of benign from malignant focal splenic lesions in dogs. Twenty-nine clinical dogs with single or multiple focal splenic lesions detected by conventional ultrasonography. Prospective clinical observational study. Perflubutane microbubbles-enhanced ultrasonography was performed in 29 dogs with focal splenic lesions. Qualitative assessment of the enhancement pattern was performed in the early vascular, late vascular, and parenchymal phases. In the early vascular phase, a hypoechoic pattern was significantly associated with malignancy (P=.02) with sensitivity of 38% (95% confidence interval [CI], 25-38%) and specificity of 100% (95% CI, 84-100%). In the late vascular phase, a hypoechoic pattern was significantly associated with malignancy (P=.001) with sensitivity of 81% (95% CI, 66-90%) and specificity of 85% (95% CI, 65-95%). There was no significant difference between malignant and benign lesions during the parenchymal phase. Hypoechoic splenic nodules in the early and late vascular phases with perflubutane microbubbles-enhanced ultrasonography are strongly suggestive of malignancy in dogs.

Hepatic malignancies: Correlation between sonographic findings and pathological features.

Ultrasonography (US) findings are inevitably based on pathological features. Knowledge of the pathological features of hepatic malignancies such as hepatocellular carcinoma (HCC), liver metastasis and intrahepatic cholangiocarcinoma is essential for correct US diagnosis and appropriate management. One type of hepatocarcinogenesis is step-wise development from a low-grade dysplastic nodule (DN), high-grade DN, high-grade DN with malignant foci, and well-differentiated HCC, to classical HCC. The intranodular blood supply changes in accordance with this progression. Moreover, the malignant potential tends to change as the macroscopic configuration progresses. Therefore, typical US findings of advanced HCC are a mosaic pattern, septum formation, peripheral sonolucency (halo), lateral shadow produced by fibrotic pseudocapsule, posterior echo enhancement, arterial hypervascularity with dilated intratumoral blood sinusoids, and perinodular daughter nodule formation. Bull's eye appearance is a common presentation of metastases from gastrointestinal (GI) adenocarcinomas, and represents histological findings that show an area of central necrosis surrounded by a zonal area of viable tumor. Thick zonal area reflects the layer of viable cells that are fed by minute tumor vessels. US imaging features of liver metastases from the GI tract are as follows: Bull's eye appearance, multiple masses, irregular tumor border, arterial rim-like enhancement, and hypoenhancement in the late vascular phase. Most intrahepatic cholangiocarcinomas are ductal adenocarcinomas. The bile ducts peripheral to the tumor are usually dilated because of obstruction by tumors. US imaging features of mass-forming cholangiocarcinoma are as follows: peripheral bile duct dilatation, irregular tumor border, arterial enhancement due to minute intratumoral blood sinusoids, and hypoenhancement in the late vascular phase.

Evaluation of focal fatty infiltration of the liver using color Doppler and contrast‐enhanced sonography

To investigate the vascular characteristics of focal fatty infiltration (FFI) in the liver using color Doppler sonography (CDUS) and contrast-enhanced sonography (CEUS). We prospectively examined 25 areas of FFI of the liver in 20 patients via conventional gray-scale sonography, CDUS, and CEUS. Cadence contrast pulse sequencing and the contrast agent SonoVue were used for CEUS examination. CEUS criteria for diagnosis of FFI were isoenhancement or hypoenhancement in the arterial phase and homogeneous isoenhancement in the portal and late phases. CDUS revealed a draining vein in 4 of 9 (44%) lesions in the hepatic hilum, whereas CEUS revealed a draining vein in 8 (89%) lesions. A vein was associated with the 2 lesions located at the edge of segment II on both CDUS and CEUS. Blood flow was seen on both CDUS and CEUS in the 2 lesions adjacent to the falciform ligament. In one patient, CDUS and CEUS revealed the mid-hepatic vein coursing between 2 FFIs. In the arterial phase of CEUS, the lesions were hypoenhancing in 44% (11/25), iso-enhancing in 44% (11/25), and hyperenhancing in 12% (3/25). In the portal phase and in the late vascular phase, all 25 lesions (100%) were iso-enhancing. Sensitivity of combined sonography and CDUS in the diagnosis of FFI was 44%, and overall accuracy was 81%. The sensitivity of CEUS in the diagnosis of FFI was 88%, and its overall accuracy was 96%. FFI in the porta hepatis is correlated with aberrant venous drainage. FFI around the falciform ligament may be related to divergence of the portal vein or unusual blood supply. In the arterial phase of CEUS, FFI lesions were iso-enhancing as often as they were hypoenhancing.

1089: Treatment response and treatment guidance of hepatocellular carcinoma: Value of contrast-enhanced harmonic US and RVS

Introduction: In 1999, an ultrasound contrast agent was introduced in Japan to the clinical practice of hepatology, especially to the diagnosis and treatment of hepatocellular carcinoma (HCC). Drastic change in the strategies both in the diagnosis and treatment of HCC has been achieved both by contrast agent and the associated innovation of ultrasound technologies. In this lecture, the present status of the new strategy brought by advances of US technologies in the diagnosis, evaluation of treatment response and treatment guidance will be presented. Role of harmonic imaging in the differential diagnosis of hepatic tumors. On contrast harmonic US, typical hemodynamic pattern of HCC, is demonstrated as abundant tumor vessels supplying from the periphery to the center of the tumor and dense tumor parenchymal stain with fast washout in high sensitivity and specificity. Characteristic hemodynamic pattern of metastases is peripheral tumor vessels with rim parenchymal stain in the vascular phase followed by perfusion defect in postvascular phase. Hemangiomas show hypovascular in the early arterial phase with gradual spotty or cotton-wool pooling lasting up to late vascular phase, which is only detected by the long interval-delay scanning. Dysplastic nodules are demonstrated as no early arterial supply with isovascularity in late vascular phase. Focal nodular hyperplasias are demonstrated as spoke-wheel pattern of blood vessels accompanied by dense stain at interval-delay scanning. Pure Arterial Phase Imaging. In 2005, a breakthrough technology, pure arterial phase imaging, which can depict only arterial accumulated MIP images, was developed by the advancement of raw data store technique and accumulation technique. By using these techniques, whether blood supply in the tumor is arterial or portal origin can be clearly depicted, which is not possible by CT or MRI. This is an innovative technique to differentiate premalignant lesion from overt HCC. Application of harmonic imaging to the treatment of HCC evaluation of treatment responses. Harmonic US is extremely useful in the evaluation of posttreatment response of HCC after Lipiodol TAE. Harmonic US can extract only the blood flow echoes created by destruction of microbubbles, whilst echoes from tissue are effectively cancelled. This mode makes it possible to clearly depict residual blood flow in tumors after RFA or PEI therapy. Real-time needle insertion guidance for local treatment of HCC. The capability of harmonic US for depicting residual cancer cells in HCCs after treatment facilitates a correct guidance for the insertion of a needle on US monitoring, which cannot be achieved by any other imaging modalities including CT or MRI. Real-time virtual sonography. Recently, concurrent real-time imaging of MDCT and US is easily obtained, which is called as real-time virtual sonography. This technique extremely facilitates the treatment guidance for HCC. Conclusion. The newly introduced sonographic technique is drastically changing the diagnostic and therapeutic strategy of HCC, resulting in an eventual improvement in the prognosis of HCC patients.

Assessment of treatment efficacy in radiofrequency ablation for hepatocellular carcinoma: Comparison between multiplanar reconstruction by multi-detector row CT and contrast-enhanced ultrasonography by Truagent detection mode

We compared the image of multiplanar reconstruction (MPR) by multi-detector row CT (MDCT) and contrast-enhanced ultrasonography (CEUS) by Truagent Detection Modetrade mark after radiofrequency ablation (RFA) for hepatocellular carcinoma to assess treatment efficacy. We examined 16 nodules in 15 patients who underwent CEUS just before and on the day following RFA, and then CT-MPR by MDCT 5 or 6 days after RFA. We measured the lengths of the major and minor axes at the maximal necrotic area, which were thought to correspond to similarly shaped images on both CT-MPR and CEUS. There are significant positive correlations in the lengths of the major and minor axes at the maximal necrotic area as measured on CT-MPR and CEUS. The differences in the lengths of the major and minor axes between CT-MPR and the parenchymal phase of CEUS were smaller than those between CT-MPR and the late vascular phase of CEUS. Our study showed a non-enhanced area of CT-MPR 5 or 6 days after RFA was similar to that of the parenchymal phase of CEUS on the day following RFA, and so it is possible to assess the treatment efficacy by CEUS on the day following RFA.

Detection of Intratumoral Vascularity in Small Hepatocellular Carcinoma by Coded Phase Inversion Harmonics

Objective: To investigate the value of contrast-enhanced coded phase inversion harmonic imaging (PIHI) in the depiction of intratumoral vascularity in small hepatocellular carcinoma (HCC). Methods: Eighty-five patients with 106 HCCs ≤3 cm in diameter were evaluated with coded harmonic angio (CHA), a coded PIHI, with use of an intravenous contrast medium, Levovist. Intratumoral vessels were detected in the early arterial phase, and tumor parenchymal stain was demonstrated in the late vascular phase. The detectability of intratumoral vascularity on contrast-enhanced CHA was compared with that on dynamic computed tomography (CT) and digital subtraction angiography (DSA). Results: With a combination of both vessel images and parenchymal flow images demonstrated by contrast-enhanced CHA, 98 of 106 small HCCs were evaluated as being hypervascular or isovascular. Using the results on dynamic CT as a gold standard, the sensitivity, specificity and accuracy were 95.1, 100 and 95.3%, respectively. The detection rate of intratumoral vascularity by contrast-enhanced CHA was 92.5% (98/ 106), compared with 97.2% (103/106) on dynamic CT (p = 0.14) and 88.9% (40/45) on DSA (p = 0.53). Conclusions: Contrast-enhanced coded PIHI is a sensitive tool for depicting intratumoral vascularity of small HCC.

Clinical utility of sequential imaging of hepatocellular carcinoma by contrast-enhanced power Doppler ultrasonograpy

The aim of this study was to investigate the clinical utility of sequential imaging of hepatocellular carcinoma (HCC) by contrast-enhanced power Doppler ultrasonograpy (CE-PDUS) to differentiate hepatocellular carcinoma from adenomatous hyperplasia (AH) and regenerated nodule (RN) and to predict the degree of differentiation of HCC. Fifty-one patients with 62 hepatic lesions including 33 moderately and poorly differentiated HCCs, 19 well-differentiated HCCs, seven AHs and three large RNs were examined by CE-PDUS. The imaging patterns during early arterial phase (tumor vessel image), late vascular phase (tumor perfusion image) and post-vascular phase (liver perfusion image) were classified as diffuse, basket, peripheral, central and no enhancement; as whole tumor, partial tumor and no enhancement; as whole tumor, partial tumor and no defect, respectively. The diffuse pattern in the tumor vessel image, the whole enhancement pattern in the tumor perfusion image and the whole defect pattern in the liver perfusion image were observed in moderately and poorly differentiated HCCs only. The basket pattern in the tumor vessel image and the partial defect pattern in the tumor perfusion image were observed in HCCs only. All AH/RNs showed no defect pattern in the liver perfusion image. The sequential imaging of HCC during early arterial, late vascular and post-vascular phases by CE-PDUS is clinically useful to differentiate HCC from AH/RN and to predict the degree of differentiation of HCC.

Value of new contrast harmonic technique for detecting tumor vascularity in hepatocellular carcinoma: Preliminary results.

To investigate the value of a new wide-band contrast harmonic imaging method in depicting intratumoral vascularity in hepatocellular carcinoma. Twenty-two patients with 28 hepatocellular carcinoma nodules evaluated with Contrast Harmonic Echo, a new wide-band harmonic imaging method, using Levovist(®) as a contrast-enhancing agent. Intermittent imaging was carried out in the early arterial phase for 10 to 40 seconds, in the late vascular phase for 1 to 2 minutes, and in the postvascular phase for 5 to 7 minutes. Subtraction images were obtained using the multishot method during the late vascular phase. The ability of Contrast Harmonic Echo imaging to detect vascularity in hepatocellular carcinoma was compared to that of unenhanced color Doppler imaging by analzing results obtained using dynamic CT as a gold standard. Contrast harmonic Echo imaging detected intratumoral vessels, tumor parenchymal stain, and perfusion defect in the early arterial phase, the late vascular phase, and the postvascular phase, respectively. In the late vascular phase, the subtraction image clearly delineated the tumor parenchymal strain. Intratumoral vascularity was detected in 25 (89%) of the hepatocellular carcinoma nodules by Contrast Harmonic Echo, compared with 15 (54%) when color Doppler imaging was used (p<0.05). The diagnostic sensitivity, specificity, and accuracy of Contrast Harmonic Echo were 96.1%, 100% and 96.4%, respectively, corresponding to results obtained using dynamic CT. Contrast Harmonic Echo imaging is superior to unenhanced color Doppler imaging in depicting intratumoral vessels and parenchymal stain, and agrees closely with results obtained with three-phase dynamic CT.

Contrast-enhanced agent detection imaging: Early experience in hepatocellular carcinoma.

To investigate the usefulness of contrast-enhanced Agent Detection Imaging in assessing intratumoral vasculature in hepatocellular carcinoma. Fourteen hepatocellular carcinoma nodules in 11 patients were studied with contrast-enhanced Agent Detection Imaging, a wide-band color Doppler imaging method, employing, Levovist(®), a microbubble contrast agent. High acoustic power was used with contrast-enhanced Agent Detection Imaging. Intermittent transmission of Agent Detection Imaging was performed at intervals of 200, 500, and 350 milliseconds in the early arterial phase (10 to 40 seconds), late vascular phase (1 to 3 minutes) and postvascular phase (5 to 7 minutes), respectively. The results were compared with those of three-phase dynamic CT. Intratumoral blood vessels in the early arterial phase and tumor parenchymal stain in the late vascular phase were depicted in 12 (88%) of the 14 hepatocellular carcinoma nodules, while all nodules were demonstrated as perfusion defect in the postvascular phase on contrast-enhanced Agent Detection Imaging. The results of Agent Detection Imaging, that were compared with those of dynamic CT, were all 100% : diagnostic sensitivity (12/12), specificity (2/2), and accurary (14/14). Contrast-enhanced Agent Detection Imaging is a promising method for depicting intratumoral vascularity in hepatocellular carcinoma.

Clinical utility of sequential imaging of hepatocellular carcinoma by contrast-enhanced power Doppler ultrasonograpy

The aim of this study was to investigate the clinical utility of sequential imaging of hepatocellular carcinoma by contrast-enhanced power Doppler ultrasonograpy (CE-PDUS) to differentiate hepatocellular carcinoma (HCC) from adenomatous hyperplasia (AH) and regenerated nodule (RN) and to predict the degree of differentiation of HCC. Fifty-one patients with 62 hepatic lesions including 33 moderately and poorly differentiated HCCs, 19 well differentiated HCCs, seven AHs and three large RNs were examined by CE-PDUS. The imaging patterns during early arterial phase (tumor vessel image), late vascular phase (tumor perfusion image) and post-vascular phase (liver perfusion image) were classified as diffuse, basket, peripheral, central and no enhancement; as whole tumor, partial tumor and no enhancement; as whole tumor, partial tumor and no defect, respectively. The diffuse pattern in the tumor vessel image, the whole enhancement pattern in the tumor perfusion image and the whole defect pattern in the liver perfusion image were observed in moderately and poorly differentiated HCCs only. The basket pattern in the tumor vessel image and the partial defect pattern in the tumor perfusion image were observed in HCCs only. All AH/RNs showed no defect pattern in the liver perfusion image. The sequential imaging of HCC during early arterial, late vascular and post-vascular phases by CE-PDUS is clinically useful to differentiate HCC from AH/RN and to predict the degree of differentiation of HCC.

Contrast advanced dynamic flow imaging and contrast pulse subtraction imaging: Preliminary results in hepatic tumors.

To investigate the usefulness of contrast advanced dynamic flow imaging and contrast pulse subtraction imaging in the intranodular hemodynamics of hepatic tumors. Ten patients underwent contrast advanced dynamic flow imaging and contrast pulse subtraction imaging using Levovist(®), a microbubble contrast agent. Fourteen hepatic tumor nodules were studied: 9 were hepatocellular carcinoma, 1 metastasis, 1 hemangioma, 1 adenomatous hyperplasia, and 2 metastatic lymph nodes of hepatocellular carcinoma. Real-time scanning of contrast advanced dynamic flow imaging and intermittent interval-delay scanning of contrast pulse subtraction imaging were carried out in the early arterial phase, the late vascular phase, and the postvascular phase. The results obtained from contrast advanced dynamic flow imaging and contrast pulse subtraction imaging were compared with those obtained by precontrast power Doppler imaging and three-phase dynamic CT, respectively. The rate of detection of intranodular vascularity by contrast advanced dynamic flow imaging (93%) or contrast pulse subtraction imaging (93%) was significantly higher than that of precontrast power Doppler imaging (29%) and was as high as that of dynamic CT. Characteristic intranodular hemodynamics were detected in hepatocellular carcinoma, metastasis, hemangioma, and adenomatous hyperplasia with typical appearance of an intranodular blood vessel image in the early arterial phase, a parenchymal stain image in the late vascular phase, and a perfusion defect image in the post-vascular phase. Contrast advanced dynamic flow imaging and contrast pulse subtraction imaging clearly show the intranodular hemodynamics in hepatic tumors.

Pleural-changes in the lung allograft during acute rejection.

To ascertain the cause of pleural fibrosis in lung allografts, pleural changes were investigated in rat syngeneic and allogeneic lung grafts. The pleura of lung syngeneic grafts showed no pathological changes except for mild edema on the first day after transplantation. In lung allografts, recipient cells migrated into the subpleural tissue early after transplantation (latent phase). In the vascuar phase, recipient lymphocytes in the subpleural tissue increased in number, while almost all alveolar structures were free from infiltration. Both CD4-positive and CD8-positive cells infiltrated in almost equal numbers with macrophages. The subsets of infiltrating cells were similar to those of the perivascular and peribronchial areas. In the late vascular or alveolar phase, fibroblasts were observed among the infiltrating cells, and fibrotic changes started. In the destructive phase, collagen formation with marked pleural thickening was dominant. Pulmonary acute rejection should be treated at least up to the late vascular phase to prevent pleural fibrosis.