Hepatocellular carcinoma recurrence after percutaneous ablation therapy: helical CT patterns

Background: To categorize the helical computed tomographic (CT) intrahepatic recurrence patterns of hepatocellular carcinoma (HCC) after treatment with percutaneous ablation procedures. Methods: Double-phase helical CT studies of 67 patients with HCC recurrence were reviewed. The study population had undergone percutaneous ablation therapy procedures (multisession or single-session ethanol injection therapy, radiofrequency thermal ablation therapy, and interstitial laser photocoagulation therapy) for 120 HCC nodules. Results: Four patterns were defined. (A) Enhancing tissue within the edge of the ablated nodule on arterial phase images (ingrowth): this pattern was seen in five treated lesions (4.2% of all treated nodules) in five patients (7.5% of all patients with recurrence) 3–7 months after treatment (mean = 4 months). (B) Enhancing tissue around the treated nodule but continuously to its border on arterial-phase images (outgrowth): this pattern was found in 12 (10%) treated lesions in 12 patients (18%) 3–6 months after ablation (mean = 4 months). (C) Enhancing tissue within the same segment of the treated nodule on arterial phase images (spread): this pattern was detected in 10 (8%) treated lesions in 10 patients (15%) 3–6 months after treatment (mean = 5 months). (D) Enhancing tissue within different segments from the treated nodule on arterial phase images (progression): this pattern was identified in 34 patients (51%) with 53 (44%) treated tumors 5–22 months after ablation (mean = 8 months). A mixed pattern was found in six subjects (9%) with seven (6%) treated nodules. Among the 61 patients with a nonmixed pattern, there were 85 treated nodules with persistent necrosis, 17 treated nodules with local recurrence (pattern A or B), and 107 new nodules due to nonlocal recurrence (pattern C or D). Portal phase enhanced images and especially unenhanced images showed a lower detection rate and a lower lesion-to-liver conspicuity score (for all patterns but mainly for pattern C). Conclusion: Four patterns of recurrence after percutaneous ablation procedures can be categorized on double-phase helical CT and are best depicted on arterial phase images. Knowledge of these patterns is relevant for early detection and may be helpful in understanding the recurrence mechanism. Received: 25 September 2000/Accepted: 15 November 2000     

Needle-tract implantation in hepatocellular carcinoma: frequency and CT findings after biopsy with a 19.5-gauge automated biopsy gun

BACKGROUND: Needle-tract implantation is an important complication of cutting biopsy of hepatocellular carcinoma (HCC). This study was performed to evaluate the frequency of needle-tract implantation after ultrasound (US)-guided percutaneous biopsy of HCC and to describe triple-phase helical computed tomographic (CT) findings of implanted nodules. METHODS: Between April 1994 and December 1997, 205 patients underwent US-guided percutaneous biopsy for HCC. Review of medical records and the pathology database disclosed seven patients who were found to have needle-tract implantation of HCC. Among these patients, five underwent triple-phase helical CT examination. We analyzed the frequency of needle-tract implantation and triple-phase helical CT findings of implanted nodules, with particular attention to the morphology and enhancement pattern. RESULTS: Seven of 205 patients (3.4%) had tumor implantation along the needle tract at histologic examination after surgical resection. Eight implanted nodules in five patients were found on triple-phase helical CT images (one nodule in three patients, two nodules in one patient, and three nodules in one patient). All implanted nodules has well-circumscribed margins and were ovoid or lobulated in contour. On triple-phase helical CT, six (75%) implanted nodules were isodense compared with abdominal wall muscle on all triple-phase CTs, and two (25%) nodules were hyperdense on hepatic arterial and portal venous phases and isodense on equilibrium phase. CONCLUSIONS: The frequency of needle-tract implantation of HCC after percutaneous needle biopsy was higher than reported previously, and careful attention should be paid during interpretation of CT images in patients with a history of previous percutaneous biopsy.     

螺旋CT双期动态扫描对肝转移瘤的诊断价值

目的:探讨肝转移瘤双期动态增强扫描的CT征象。方法:应用螺旋CT对67例肝转移瘤病人分别进行平扫、增强后肝动脉期和门静脉期扫描,观察瘤灶双期动态扫描的CT征象。结果:(1)67例中29例肝动脉期瘤灶边缘部出现环形强化,其强化密度高于正常肝,低于主动脉。门静脉期瘤灶边缘部的环形强化范围不扩大,其中27例密度仍可高于或等于正常肝,2例密度低于正常肝。(2)67例中22例肝动脉期和门静脉期瘤灶边缘部和瘤内均无明显强化,密度低于正常肝。(3)67例中7例肝动脉期瘤灶出现全瘤均匀性或不均匀性强化,密度高于正常肝;门静脉期瘤灶密度下降,密度等于或低于正常肝。(4)67例中8例肝动脉期多发的肝转移瘤中,一部分瘤灶出现全瘤均匀性或不均匀性强化,或边缘部环形强化,密度高于正常肝;门静脉期密度下降至等于或低于正常肝。另一部分瘤灶则动、门脉双期均始终未见强化。结论:肝转移瘤CT双期动态增强扫描的主要征象是:(1)动脉期瘤灶边缘部出现密度高于正常肝的环形强化,门静脉期此环形强化范围无扩大,密度仍高于或等于正常肝。(2)双期扫描瘤灶均无强化,呈低密度。(3)双期扫描部分瘤灶强化,另一部分瘤灶则始终未见强化。     

Optimal phases of dynamic CT for detecting hepatocellular carcinoma: evaluation of unenhanced and triple-phase images

Background: To determine the optimal phases of dynamic computed tomography (CT) for detecting hepatocellular carcinoma (HCC). Methods: Fifty-two patients with 85 HCC nodules were examined by means of unenhanced and triple-phase CT images of the whole liver. The time for obtaining the arterial-phase images was 25–55 s after intravenous bolus injection of contrast material, the time for obtaining the portal venous-phase images was 65–100 s, and the time for obtaining late-phase images was 145 s to 4 min. Detectability of the HCC nodules for all phases was statistically compared. Results: The detection rates for the arterial- and late-phase images were significantly higher than for the unenhanced and portal venous-phase images (p < 0.01). The combination of arterial- and late-phase images showed the same number of HCC nodules in the same number of patients as did the combination of unenhanced and triple-phase images. Conclusion: The combination of the arterial- and late-phase imagings was best for detecting HCC nodules. Received: 8 July 1998/Revision accepted: 18 November 1998     

Significance of hyperattenuating and contrast-enhancing hepatic nodules detected in the cirrhotic liver during arterial phase helical CT in pre–liver transplant patients: radiologic–histopathologic correlation of explanted livers

Background: Hyperattenuating nodules detected by arterial phase helical computed tomography (HCT) in patients with cirrhosis usually are believed to represent hepatocellular carcinomas (HCCs). We correlated HCT morphology of hyperattenuating hepatic nodules detected during arterial phase scans with the histopathology of explanted livers of patients with hepatic cirrhosis undergoing liver transplantation. Methods: Three hundred fifty-four patients had arterial and portal phase HCT performed before subsequent hepatic transplantation. Each patient received 180 mL of contrast by power injection at 5 mL/s. All hyperattenuating nodules detected on arterial phase HCT were assessed for morphology and evidence for contrast enhancement. Explanted livers in all patients were then sectioned at 10-mm intervals, and the histology of the nodules was correlated with the HCT findings. Results: Sixty-one hyperattenuating nodules were detected on the arterial phase HCT in 43 patients: 41 nodules were benign regenerating nodules (RN), three were dysplastic nodules (DP), and 17 were HCCs. Most RN/DP nodules were 5–20 mm in diameter, had distinct margins, were homogeneous, and were isoattenuating on precontrast, portal, and delayed scans. Thirty-six showed positive contrast enhancement and displayed a wide range of attenuation profiles. HCC nodules were 6–50 mm. All showed positive contrast enhancement and displayed a wide range of attenuation profiles. Conclusion: Hyperattenuating nodules seen on arterial phase HCT are likely to be RN/DP nodules. In many cases, it is not possible to distinguish between RN/DP and HCC. Thus, clinical decisions regarding inclusion criteria for transplantation based on CT morphology of liver lesions may be tenuous.     

Hepatic focal nodular hyperplasia: CT and sonographic spectrum

Fifteen patients with pathologically proven focal nodular hyperplasia (FNH) of the liver had abdominal computed tomography (CT) (15) and ultrasound (11). In seven patients, the lesions were incidentally found during gallbladder or renal examination, whereas the other eight had a primary neoplasm and the liver was studied for possible metastasis. In 11 unenhanced CT scans, the ratio of isodense to hypodense lesions was 8 to 3. In 15 contrasten-hanced CT scans, seven were isodense, six were hypodense, and in two, the lesion enhanced (hyperdense). In seven patients a hypodense lesion on unenhanced CT became isodense with contrast injection. Delayed images in three showed the lesions appearing as hypodense in two and displaying a rim of enhancement in one. In one case, unenhanced CT was normal and only enhanced CT showed an area of homogeneous increased density. Ultrasound was done in 11 patients, the lesion was hypoechoic to the liver in five, echogenic in four, and isoechoic in two. Findings of central scar were seen on CT and ultrasound in three cases. Pathologic diagnosis was available in all cases, seven by needle aspiration and eight by surgical resection. In our experience, FNH has many CT and sonographic features that can mimic hemangioma or metastasis. While the presence of a central scar increases the specificity, in a cancer patient, the findings should be interpreted with caution and needle aspiration should be obtained.     

Intrahepatic bile duct dilatation secondary to hepatocellular carcinoma: CT features in 10 patients

Background: To determine the computed tomographic (CT) features of bile duct obstruction secondary to hepatocellular carcinoma (HCC). Methods: CT examinations of 10 patients (mean age, 58 years) with bile duct obstruction secondary to HCC were retrospectively reviewed. Results: All tumors were intrahepatic. Eight tumors were well-delineated and two were ill-defined. The largest diameters of tumor ranged from 1.5–6.0 cm (mean, 3.6 cm). All tumors were hypodense before contrast and did not contain calcification. After contrast, four tumors became hypodense, three were isodense, and three were hyperdense to the liver. No tumor demonstrated encapsulation. Diffuse intrahepatic bile duct dilatation was observed in seven patients. One patient had extrahepatic bile duct dilatation. Localized bile duct dilatation was observed in three patients, in the hemi-liver which contained the tumor. No tumor invaded the portal vein. Conclusion: Although rare, HCC should be included in the differential diagnosis of bile duct obstruction. This diagnosis should be suggested in patients with bile duct obstruction when CT shows an associated intra- or extrahepatic mass. Our results suggest that HCC responsible for bile duct obstruction is remarkable for the absence of encapsulation.     

肝脏局灶性结节增生螺旋CT诊断12例

目的探讨肝脏局灶性结节增生（FNH）在螺旋CT扫描中的表现及诊断价值。方法回顾分析12例经病理证实的肝脏FNH的螺旋CT平扫及动态增强资料。结果12个病灶平扫低密度7个,等密度5个,其中8个中央见星芒状更低密度区;增强扫描：动脉期11个病灶明显强化,1个中等强化,病灶中央更低密度区无强化,5例病灶中央或周围可见增粗的血管影。门脉期及延迟期：2个等或略低密度,10个为略高密度,8例中央瘢痕中6例有延迟强化,2例无强化。结论FNH在螺旋CT平扫和动态增强扫描中具有特征表现,对FNH的确诊有重要价值。     

Small hepatocellular carcinoma: differentiation from adenomatous hyperplasia with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging

Background: To investigate the usefulness of color Doppler ultrasound (US) and dynamic Gd-DTPA-enhanced magnetic resonance (MR) imaging in the differentiation of small hepatocellular carcinoma (HCC) and adenomatous hyperplasia (AH). Methods: Thirty-eight small (3 cm or less) nodular lesions (in 38 cirrhotic patients) with US features consistent with HCC underwent evaluation with color Doppler US and MR imaging. Breath-hold T1-weighted rapid acquisition spin echo MR sequence after bolus injection of 0.1 mmol/kg gadopentetate dimeglumine was used to evaluate dynamic enhancement. US-guided tissue-core percutaneous biopsy established the diagnosis: HCC in 28 cases and AH in 10. Results: Color signals with pulsatile or continuous Doppler spectrum were demonstrated in 19 of 28 HCCs (68%) but in none of the AHs. Although there was considerable overlap in signal intensity between HCC and AH on both unenhanced T1- and T2-weighted images, early enhancement on breath-hold T1-weighted images obtained 40 s after starting contrast administration was observed in 22 of 28 HCCs (79%) but in none of the AHs. In 26 of 28 HCCs (93%), pulsatile or continuous flow at color Doppler US, early enhancement at dynamic MR imaging, or both were observed. Conclusion: Findings with color Doppler US and dynamic Gd-DTPA-enhanced MR imaging enable a reliable distinction between small HCC and AH. Received: 8 August 1994/Accepted after revision: 27 January 1995     

肾脏恶性肿瘤的CT诊断（附15例报告）

目的：旨在提高对肾脏恶性肿瘤CT表现的认识及诊断。材料与方法：分析了15例经手术病理证实的肾脏恶性肿瘤CT表现。15例均作了常规CT扫描,其中10例作了增强扫描。结果：肿瘤发生在肾实质12例,肾盂3例。肿瘤病灶表现为高密度3例、低密度4例、等密度3例及混杂密度5例,增强扫描时病灶有轻度强化。结论：CT扫描对肾脏恶性肿瘤有重要诊断价值。     

Spontaneous rectus sheath hematomas: clinical and radiological features

We reviewed the clinical and radiological features in eight patients with spontaneous rectus sheath hematoma (RSH). The diagnosis was confirmed at surgery in four patients, and spontaneous resolution occurred in the other four. All patients were elderly adults. Acute abdominal pain and a palpable mass after muscular strain, such as coughing or twisting, were features highly suggestive of RSH. Sonographically, these hematomas may be confused with abdominal wall tumors. On CT scans, a hyperdense mass posterior to the rectus abdominis muscle with ipsilateral anterolateral muscular enlargement is considered characteristic of acute RSH, although chronic RSH may be isodense or hypodense relative to the surrounding muscle. MRI is very useful in the diagnosis of RSH, which is demonstrated as a high signal intensity area on both T1- and T2-weighted images, especially when the CT findings are not specific for RSH. Received: 16 August 1994/Accepted: 3 October 1994     

Small hepatic nodules in cirrhosis: ultrasonographic, CT, and MR imaging findings

Purpose: The purpose of this study was to assess the imaging findings of pathologically-proved small hepatic nodules 2 cm in size or smaller detected with ultrasonography in cirrhotic patients with suspected hepatocellular carcinoma (HCC). Materials and Methods: We evaluated sonographically detected 32 small hepatic nodules which were pathologically confirmed in 23 consecutive cirrhotic patients who were suspected of having HCC. Twenty-six lesions were confirmed with ultrasonographically-guided aspiration needle-core biopsy, and six with definitive surgery. Ultrasonographic examination records were retrospectively reviewed. CT, and MR images obtained with various imaging techniques were retrospectively reviewed by two radiologists in a blind fashion. Results: The 32 hepatic nodules were comprised of seven focal fatty changes, two large regenerative nodules, three low-grade dysplastic nodules, five high-grade dysplastic nodules, and fifteen HCCs. Ultrasonography showed various echogenicity for the hepatic nodules. The signal-intensity characteristics with T1-weighted spin-echo, in-phase gradient-recalled-echo, and dynamic MR imagings may be useful in distinguishing HCC from nonHCC nodules. Conclusions: Nearly half of small hepatic nodules detected with ultrasonography were nonHCC nodules. Ultrasonographic findings may not be reliable in characterizing small hepatic nodules in cirrhosis. CT and MR imaging obtained with the various techniques are still insensitive to these hepatic nodules. RID="ID="<e5>Correspondence to:</e5> M. Kanematsu Received: 25 August 1997/Revision accepted: 19 November 1997     

Late-phase enhancement of the upstream portion of pancreatic adenocarcinoma on dual-phase helical CT

Background: Late-phase enhancement of pancreatic parenchyma upstream (tail side) of pancreatic adenocarcinoma is found frequently on dual-phase helical computed tomography (CT). We measured the frequency of late-phase enhancement of the upstream portion of pancreatic adenocarcinoma and normal pancreatic parenchyma using dual-phase helical CT. Methods: Twenty-one patients with pancreatic adenocarcinoma and nontumorous pancreas upstream of tumors were compared with 100 control patients without pancreatic disease. Early and late scans started at 25 and 75 s, respectively, after intravenous injection of contrast material. The attenuation values of normal and nontumorous pancreas upstream of tumors were assessed in three phases: precontrast, early, and late enhanced. Enhancement ratio (ER) was calculated as ER = (late phase − precontrast)/(early phase − precontrast). Results: Late-phase enhancements (ER > 1.0) were seen in 86% of upstream pancreas and 10% of normal pancreas. The mean ER of upstream pancreas was significantly higher than that of normal pancreas (p < 0.01). Conclusion: Late-phase enhancement of the pancreas upstream of the tumor is frequently observed in patients with pancreatic adenocarcinoma. Late-phase enhancement and histology showed a correlation for chronic obstructing pancreatitis in five patients. Received: 30 October 2000/Revision accepted: 7 February 2001     

Urinary excretion of orally ingested gastrografin on CT

Renal excretion of orally ingested gastrografin has rarely been reported on computed tomography (CT). We studied the unenhanced scans of 82 patients with bowel disorders or perforation to assess the prevalence of urinary contrast material (CM) in various bowel diseases. We also assessed the clinical significance of this sign. In addition, we reviewed the unenhanced CT scans of 100 randomly selected patients without bowel diseases as a control group. Twenty-nine of the 58 patients with bowel diseases, six of nine with free perforation, and one of 15 with covered perforation had CM in the urinary tract. None of the 100 without bowel disease showed urinary CM. Statistical analysis was done by using the Fisher's exact test. The prevalence of urinary CM was highest in inflammatory bowel disease, radiation enteritis, and free perforation (p < 0.0001). This study shows that the CT finding of orally ingested gastrografin in the urinary tract differentiates patients with bowel disease from those without. Received: 2/13/97/Accepted: 3/19/97     

肝局灶性结节增生的CT与MRI诊断

目的探讨肝局灶性结节增生（FNH）的CT和MRI表现,以提高FNH诊断准确性。方法回顾性分析20例经手术病理证实的24个FNH病灶的影像学资料,包括CT检查13例,MRI检查10例,其中3例同时做了CT及MRI检查。结果18例为单发病灶,2例为多发病灶。CT及MRI检出病灶数均为14个。CT平扫低密度9个,等密度5个。MRI平扫T1WI低信号10个,等信号4个;T2WI显示14个均呈高或稍高信号。所有病灶实质动脉期cT及MRI均明显强化。cT显示门脉期9个等密度,4个稍高密度,1个低密度;延迟期11个等密度,2个稍高密度,1个稍低密度。MRI显示门脉期高信号11个,等信号3个;延迟期高信号10个,等信号4个。CT多期扫描8个病灶伴有中央瘢痕,7个周边有扭曲、增粗血供,3个有假包膜。MRI多期扫描9个病灶伴有中央瘢痕,6个周边有扭曲、增粗血供,5个有假包膜。结论CT及MRI多期扫描可充分反映FNH的供血特点及病理特征,在FNH诊断与鉴别诊断中具有重要的价值。     

Preoperative evaluation of gastric cancer: value of spiral CT during gastric arteriography (CTGA)

Background: To evaluate the utility of dual-phase spiral computed tomography during gastric arteriography (CTGA) in the preoperative staging of gastric cancers. Methods: We performed CTGA in 21 patients with pathologically proven gastric cancers. CTGA findings were prospectively analyzed and correlated with surgical and pathologic findings. Dual-phase scans were performed at 10 s (early) and 60–100 s (delayed) after injection of 120 mL of contrast medium at an injection rate of 6 mL/s through a preset 5-Fr catheter positioned in the celiac trunk. Spiral CT scans were assessed for enhancing pattern of the normal gastric wall, tumor detectability, and accuracy of tumor staging. Results: Normal gastric mucosa was clearly visible as two or three layers in all patients on early-phase scans and in eight patients on delayed-phase scans. The primary tumors were correctly detected with CTGA in seven (88%) of the eight early gastric cancers and in all 13 (100%) advanced gastric cancers. The accuracy of CTGA for T staging was 50% and 77% in early and advanced gastric cancers, respectively. The overall accuracy for tumor detection and T staging was 95% and 67%, respectively. The accuracy of CTGA for the degree of serosal invasion and regional lymph node metastasis was 77% and 76%, respectively. Conclusion: The CTGA technique improved tumor detection rate and accuracy of tumor staging, especially in early gastric cancer, and may be very useful in the preoperative staging of gastric cancer. Received: 31 August 2000/Accepted: 20 September 2000     

Helical CT of the small bowel with an alternative oral contrast material in patients with Crohn disease

Background: We assessed the usefulness of helical computed tomography (CT) with a negative oral contrast material for detecting Crohn disease. Methods: Thirty-eight patients with proven Crohn disease were examined. We administered a large volume of a new negative oral contrast material (Mucofalk suspended in water) and then proceeded with helical CT scanning. This technique is an alternative to CT and conventional enteroclyses that use a nasojejunal tube. Two radiologists interpreted the scans, and patients were interviewed about their tolerance of the procedure. We created multiplanar reformatted images in all cases. Potential of small bowel distention by Mucofalk was evaluated by two observers on a three-point scale, and interobserver agreement was calculated with κ statistics. Results: All patients who underwent enteroclysis stated that CT was the more comfortable method, the taste of the peroral contrast medium was considered good by 52.6% and acceptable by 47.4%. Small bowel distention was excellent in 55% of cases, moderate in 26%, and poor in 19%, with an interoberserver agreement of 78%. CT findings correlated with enteroclysis in 27 patients who underwent both methods. Analysis of CT versus enteroclysis showed a sensitivity of 89% for CT versus 78% for small bowel enteroclysis. Conclusion: Mucofalk CT is a simple, rapid, noninvasive, and accurate method of evaluating extramucosal manifestations of Crohn disease. The tubeless procedure improved patients' comfort and decreased time, cost, and radiation exposure.     

Dysplastic nodules of the liver: imaging findings

Background: To verify characteristic features of hepatic dysplastic nodules at different imaging modalities. Methods: Twenty-eight patients with 37 dysplastic nodules of the liver (0.8–3.0 cm) underwent sonography (28 patients), computed tomography (CT; 24 patients), magnetic resonance (MR; 11 patients), and angiography (12 patients). Each nodule was analyzed for echogenicity, attenuation, signal intensity, and vascularity. Results: Echogenicity of nodules was high in 16 (43%), homogeneous in two (6%), and low in 19 (51%) of 37 nodules. Attenuation of nodules was high in one (7%), homogeneous in four (26%), and low in 10 (67%) of 15 nodules on the arterial-phase CT images; homogeneous in five (33%) and low in 10 (67%) of 15 nodules on the portal-phase CT images; and high in four (17%), homogeneous in six (26%), and low in 13 (57%) of 23 nodules on the delayed-phase CT images. Signal intensity of nodules was high in 15 (94%) and homogeneous in one (6%) of 16 nodules on T1-weighted MR images and was homogeneous in seven (44%) and low in nine (56%) of 16 nodules on T2-weighted MR images. Vascularity of nodules was avascular in 14 (88%) and slightly vascular in two (12%) of 16 nodules. Conclusions: Hepatic dysplastic nodules show diverse imaging characteristics with different imaging techniques; however, common imaging findings of hepatic dysplastic nodules are low echo, low attenuation, and high, low, or homogeneous intensity on T1- and T2-weighted MR, and avascularity. Received: 13 May 1998/Accepted: 1 July 1998     

Therapeutic response evaluation of malignant hepatic masses treated by interventional procedures with contrast-enhanced agent detection imaging.

OBJECTIVE: To assess the usefulness of microbubble contrast-enhanced agent detection imaging in evaluating the therapeutic response of malignant hepatic masses to treatment with interventional procedures. METHODS: Fifty-eight patients with 68 hepatocellular carcinomas and 6 metastases who were treated with interventional procedures were evaluated with SH U 508A-enhanced agent detection imaging and helical computed tomography. Helical computed tomography was also performed to help establish the outcome of therapy with unenhanced computed tomography 2 weeks after transcatheter arterial chemoembolization and with dynamic contrast-enhanced computed tomography 1 day after radio frequency ablation or percutaneous ethanol injection. The studies were reviewed separately and randomly, and the sensitivity and specificity of agent detection imaging for detection of viable tumor residue were determined by follow-up imaging performed at least 3 months later. RESULTS: Follow-up computed tomography or magnetic resonance imaging revealed complete tumor responses in 44 (59.5%) of 74 cases after the therapeutic procedures. The sensitivity of agent detection imaging was 94.7% after transcatheter arterial chemoembolization and 72.7% after radio frequency ablation and percutaneous ethanol injection. The specificity of agent detection imaging for the detection of residual tumors was 80% after transcatheter arterial chemoembolization and 79.2% after radio frequency ablation and percutaneous ethanol injection. The false-positive rate for agent detection imaging in cases of radio frequency ablation or percutaneous ethanol injection was 20.8% (5 of 24), resulting from reactive hyperemia or vascularity within the safety margin. In the assessment of the therapeutic effects, the concordance of contrast-enhanced agent detection imaging with helical computed tomography was statistically significant after transcatheter arterial chemoembolization (P < .00001) and radio frequency ablation or percutaneous ethanol injection (P < .02). CONCLUSIONS: Contrast-enhanced agent detection imaging proved useful and as effective as helical computed tomography for evaluating the therapeutic effects of interventional therapeutic procedures for malignant hepatic masses.     

Contrast-enhanced power Doppler sonography and helical computed tomography for assessment of vascularity of small hepatocellular carcinomas before and after percutaneous ablation

PURPOSE: We compared the usefulness of Levovist-enhanced power Doppler imaging (PDI) and helical CT in the depiction of tumor vascularity before and after percutaneous ablation of small hepatocellular carcinomas (HCCs). METHODS: Thirty-one cirrhotic patients with solitary unresectable HCCs smaller than 5 cm (mean size, 2.7 +/- 0.8 cm; range, 1.5-5.0 cm) recruited over a 15-month period were treated with percutaneous ethanol injection (n = 9) or radiofrequency ablation (n = 22). PDI, contrast-enhanced PDI (using Levovist), and multiphase contrast-enhanced helical CT were performed before and after percutaneous ablation, and vascularity findings were compared. RESULTS: Levovist significantly increased baseline intratumoral Doppler signals on PDI compared to non-contrast PDI. The most frequent tumor vascularity pattern was heterogeneous (45%). Vascularity was identified in all tumors by both contrast-enhanced PDI and helical CT before ablation. After percutaneous ablation, intratumoral vascularity was detected in 11 tumors by contrast-enhanced PDI and in 15 tumors by CT. The sensitivity, specificity, and diagnostic accuracy of contrast-enhanced PDI in demonstrating intratumoral vascularity, with CT being the gold standard, were 66%, 93%, and 81%, respectively. There was significant agreement between the 2 modalities in the depiction of tumor vascularity after ablation (kappa = 0.6, p = 0.001). However, there were 5 false negatives and 1 false positive with contrast-enhanced PDI. Complete tumor necrosis was achieved in 21 patients (68%). CONCLUSIONS: There was a good concordance between contrast-enhanced PDI and helical CT in the depiction of HCC vascularity before and after percutaneous ablation. However, although contrast-enhanced PDI may be useful for real-time guidance of treatment, its low sensitivity makes it inadequate to accurately assess the completeness of ablation.