Imaging findings of primary hepatic angiosarcoma on gadoxetate disodium-enhanced liver MRI: comparison with hepatic haemangiomas of similar size.

AIM: To describe imaging characteristics of primary hepatic angiosarcoma on gadoxetate disodium-enhanced dynamic magnetic resonance imaging (MRI) and to determine features that differentiate angiosarcomas from similar-sized haemangiomas. MATERIALS AND METHODS: The study included 15 patients with hepatic angiosarcomas and 35 patients with size-matched hepatic haemangiomas who underwent gadoxetate disodium-enhanced liver MRI. The number, size, growth pattern, signal intensity (SI) characteristics, and SI changes on dynamic scans were evaluated and compared between the two entities. RESULTS: Overall, hepatic angiosarcomas significantly more often showed lesion multiplicity (86.7%), capsular retraction (40%), prominent intratumoural vessels (66.7%), vascular invasion (20%), heterogeneous SI on T2-weighted (100%) and hepatobiliary phase images (80%), and intralesional haemorrhage (60%, all p<0.05). On dynamic scans, angiosarcomas demonstrated enhancing foci of irregular or rim-like nodular/linear or bizarre (86.7%) shapes, with centrifugal or bizarre patterns of progressive enhancement (53.3%). Enhancement of angiosarcomas was less than that of the blood pool on visual grading, but the enhancement curves followed that of the aorta. Regardless of size, angiosarcomas showed heterogeneous T2 SI, intratumoural haemorrhage, and heterogeneity during the hepatobiliary phase, whereas these findings were more common in haemangiomas >6 cm in diameter. CONCLUSION: Gadoxetate disodium-enhanced dynamic liver MRI is capable of depicting vascular hallmarks of hepatic angiosarcomas. Heterogeneous SI on T2-weighted and hepatobiliary phase images, multiplicity, and an enhancement curve following that of the aorta are also distinctive features that differentiate angiosarcomas from haemangiomas.

Zuckerkandl Tubercle of the Thyroid Gland: Correlations between Findings of Anatomic Dissections and CT Imaging.

BACKGROUND AND PURPOSE: The Zuckerkandl tubercle is located at the posteromedial border of the thyroid lobe, and it may be confused with a neoplasm or other mass. This study was performed to clarify the position and morphologic characteristics of the Zuckerkandl tubercle by dissecting cadavers and to compare the findings with the corresponding CT images obtained in the same cadavers. MATERIALS AND METHODS: One hundred thyroid lobes from 50 fresh cadavers were dissected for this study (20 males and 30 females; mean age at death, 77.3 ± 11.5 years). CT scans were obtained in 10 of the cadavers by using a 128-channel multidetector row CT scanner before dissection. RESULTS: The Zuckerkandl tubercle of the thyroid gland was observed in 83% of the specimens. It was mostly located at the posteromedial border of the thyroid lobe and within the middle two quarters (2nd and 3rd) of the thyroid lobe. The Zuckerkandl tubercle was classified into 3 types based on its direction of extension: posteromedial in 64% of the specimens, posteromedial and superior in 13%, and posteromedial and inferior in 6%. On axial CT, the Zuckerkandl tubercle was usually continuous with the posteromedial part of the thyroid lobe and extended posteromedially to the esophagus. The parts of the Zuckerkandl tubercle that protrude posteromedially and superiorly or posteromedially and inferiorly from the thyroid lobe appeared separated from the thyroid gland by a thin, low-density string on axial CT. CONCLUSIONS: Zuckerkandl tubercles that protrude toward the posteromedial and superior or inferior direction could cause confusion due to their separation when performing diagnoses with CT images.

Radiofrequency ablation as an alternative to hepatic resection for single small hepatocellular carcinomas.

BACKGROUND: This study aimed to investigate whether radiofrequency ablation (RFA) is an alternative to surgical resection for hepatocellular carcinoma (HCC) within the context of current guidelines. METHODS: This retrospective study included patients with normal portal pressure and serum bilirubin level who initially underwent liver resection or RFA for a single HCC of maximum size 3 cm. Between-group differences in cumulative rates of survival and recurrence specific for HCC were analysed in the entire cohort and in a propensity score-matched cohort. RESULTS: A total of 604 patients were enrolled, 273 in the liver resection group and 331 in the RFA group. The 5- and 10-year HCC-specific survival rates for the resection and RFA groups were 87·6 versus 82·1 per cent and 59·0 versus 61·2 per cent respectively (P = 0·214), whereas overall 5- and 10-year recurrence-free survival rates for the corresponding groups were 60·6 versus 39·4 per cent and 37·5 versus 25·1 per cent respectively (P < 0·001). In the propensity score-matched cohort (152 pairs), there were no differences in HCC-specific survival (hazard ratio (HR) 1·03 for RFA versus resection; P = 0·899), whereas recurrence-free survival again differed between the treatment groups (HR 1·75; P < 0·001). RFA was independently associated with poorer outcomes in terms of treatment-site recurrence-free survival (adjusted HR 1·66; P = 0·026), but not non-treatment-site recurrence-free survival (adjusted HR 1·15; P = 0·354). CONCLUSION: Although RFA carries a higher risk of treatment-site recurrence than hepatic resection, it provides comparable overall survival in patients with a single small HCC without portal hypertension or a raised bilirubin level.

Percutaneous radiofrequency ablation using internally cooled wet electrodes for treatment of colorectal liver metastases.

AIM: To evaluate the efficacy and safety of internally cooled wet (ICW) electrodes, which provide interstitial infusion of saline and intra-electrode cooling simultaneously, in the percutaneous radiofrequency ablation (RFA) of liver metastases from colorectal cancer. MATERIALS AND METHODS: From February 2008 to October 2010, 27 patients with 35 hepatic metastatic lesions (mean size 1.99cm; range 0.7-3.8cm) underwent RFA using ICW electrodes. Of these 35 tumours, 32 had diameters ≤3cm, and three had diameters of 3-4cm. Moreover, 18 tumours were non-subcapsular and 17 were subcapsular. RESULTS: No patients (0%) had major complications after RFA. During follow-up (median 27 months; range 4.5-36 months), 14 of the 35 treated lesions (40%) showed local tumour progression. The local tumour progression-free survival rates at 1 and 3 years were 73 and 56%, respectively. The local tumour progression-free survival period was significantly longer in patients with tumours ≤2cm than >2cm (p<0.001), but did not differ significantly between patients with non-subcapsular and subcapsular tumours (p=0.454). The overall 1 and 3 year survival rates after RFA were 100 and 77%, respectively. CONCLUSIONS: Percutaneous RFA using ICW electrodes is safe and technically feasible for the treatment of liver metastases from colorectal cancer. It provides effective local tumour control with low complication rates and reduced number of needle placements.

Characterization of liver metastases: the efficacy of biphasic magnetic resonance imaging with ferucarbotran-enhancement.

AIM: To retrospectively evaluate the efficacy of biphasic magnetic resonance imaging (MRI) of the liver with ferucarbotran-enhancement for the characterization of hepatic metastases. MATERIALS AND METHODS: Thirty-six patients underwent MRI of the liver with separate acquisition of double-contrast enhancement consisting of gadolinium and ferucarbotran. A total of 106 focal hepatic lesions (51 metastases, 31 cysts, 23 haemangiomas, and one eosinophilic abscess) were included. Two sets of MRI were analysed: (1) ferucarbotran set: ferucarbotran-enhanced T1-weighted (T1W) dynamic imaging combined with ferucarbotran-enhanced T2*-weighted (T2*W) delayed imaging and (2) double set: gadolinium-enhanced T1W dynamic imaging combined with ferucarbotran-enhanced T2*W delayed imaging. The diagnostic accuracy of the two sets was evaluated using alternative free-response receiver operating characteristic curve analysis. Sensitivity and specificity were compared using the McNemar test. The enhancement pattern of focal hepatic lesions was analysed on gadolinium and ferucarbotran-enhanced T1W dynamic imaging. RESULTS: There was no significant difference in the accuracy of characterizing hepatic metastases between the two sets. Sensitivity and specificity were not significantly different between the sets (p>0.05). Peripheral rim enhancement was exhibited in 57% of metastatic lesions on ferucarbotran-enhanced T1W dynamic imaging. The majority (96%) of hepatic haemangiomas demonstrated typical peripheral nodular enhancement with progression on ferucarbotran-enhanced T1W dynamic imaging and were easily differentiated from metastases. CONCLUSION: Biphasic MRI of the liver with ferucarbotran-enhancement alone provided comparable diagnostic efficacy to double-contrast MRI for the characterization of hepatic metastases.

Isolated perihepatic tuberculosis: imaging findings.

AIM: To review the imaging findings of isolated perihepatic tuberculosis without coexistent active tuberculosis elsewhere in the body. MATERIALS AND METHODS: Over a 9-year period, six patients with histopathologically proven perihepatic tuberculosis without simultaneous active tuberculosis elsewhere in the body were included in this study. Two radiologists retrospectively evaluated in consensus the location (right, left, or both perihepatic spaces), size (maximum diameter), morphology (ovoid or round), number, attenuation (low-, iso-, or high-attenuation compared with the adjacent liver parenchyma), and the presence or absence of contrast enhancement of the lesions on computed tomography (CT), and echogenicity (low-, iso-, or high-echogenicity compared with the adjacent liver parenchyma) of the lesions on ultrasonography. RESULTS: On CT, an isolated perihepatic lesion was located in the right perihepatic space in five patients, whereas three lesions were located in both perihepatic spaces in the remaining patient. The mean maximum diameter of the isolated perihepatic tuberculosis lesions was 29.7 mm. Isolated perihepatic tuberculosis appeared as an ovoid-shaped, homogeneous, and low-attenuating (n=5) or high-attenuating (n=1) lesion relative to the liver. There was peripheral rim enhancement of the lesion in two patients. On ultrasonography, isolated perihepatic tuberculosis was revealed as a homogeneous, low-echoic (n=5) or iso-echoic (n=1) lesion relative to the liver. CONCLUSION: Although various inflammatory or malignant lesions can be located in the perihepatic space, isolated perihepatic tuberculosis appears an ovoid-shaped, homogeneous, and low-attenuating or low-echoic lesion compared with the liver parenchyma on CT or ultrasonography.

Gastric schwannomas: radiological features with endoscopic and pathological correlation.

AIM: To describe the radiological, endoscopic, and pathological findings of gastric schwannomas in 16 patients. MATERIALS AND METHODS: The radiological, endoscopic, and pathological findings of 16 surgically proven cases of gastric schwannoma were retrospectively reviewed. All patients underwent computed tomography (CT) and four patients were evaluated with upper gastrointestinal series. Two radiologists reviewed the CT and upper gastrointestinal series images by consensus with regard to tumour size, contour, margin, and growth pattern, the presence or absence of ulcer, cystic change, and the CT enhancement pattern. Endoscopy was performed in eight of these 16 patients. Six patients underwent endoscopic ultrasonography. Pathological specimens were obtained from and reviewed in all 16 patients. Immunohistochemistry was performed for c-kit, CD34, smooth muscle actin, and S-100 protein. RESULTS: On radiographic examination, gastric schwannomas appeared as submucosal tumours with the CT features of well-demarcated, homogeneous, and uncommonly ulcerated masses. Endoscopy with endoscopic ultrasonography demonstrated homogeneous, submucosal masses contiguous with the muscularis propria in all six examined cases. On pathological examination, gastric schwannomas appeared as well-circumscribed and homogeneous tumours in the muscularis propria and consisted microscopically of interlacing bundles of spindle cells. Strong positivity for S-100 protein was demonstrated in all 16 cases on immunohistochemistry. CONCLUSION: Gastric schwannomas appear as submucosal tumours of the stomach and have well-demarcated and homogeneous features on CT, endoscopic ultrasonography, and gross pathology. Immunohistochemistry consistently reveals positivity for S-100 protein in the tumours.

Standardization of anti-lethal toxin potency test of antivenoms prepared from two different Agkistrodon halys venoms

In Korea, antivenoms for the treatment of patients bitten by venomous snakes have been imported from Japan or China. Although there is cross-reactivity between these antibodies and venoms from snakes indigenous to Korea (e.g. Agkistrodon genus), protection is not optimal. Antivenoms specifically prepared to neutralize Korean snake venoms could be more effective, with fewer side effects. To this end, we established an infrastructure to develop national standards and created a standardized method to evaluate the efficacy of two horse-derived antivenoms using mouse lethal toxin test. Additionally, we determined the antivenoms neutralizing activity against lethal doses (LD50) of Agkistrodon halys (from Japan) and Jiangzhe Agkistrodon halys (from China) venoms. We also performed cross-neutralization tests using probit analysis on each pairing of venom and antivenom in order to check the possibility of using Jiangzhe A. halys venom as a substitute for A. halys venom, the current standard. Slope of A. halys venom with A. halys antivenom was 10.2 and that of A. halys venom with Jiangzhe A. halys antivenom was 9.6. However, Slope of Jiangzhe A. halys venom with A. halys antivenom was 4.7 while that of Jiangzhe A. halys venom with Jiangzhe A. halys antivenom was 11.5. Therefore, the significant difference in slope patterns suggests that Jiangzhe A. halys venom cannot be used as a substitute for the standard venom to test the anti-lethal toxin activity of antivenoms (p<0.05).(AU)

Abdominal cavernous Iymphangiomas: CT findings.

Two adult patients with histopathologically proved cavernous lymphangiomas and one adult patient with lymphangiomas of strongly presumed cavernous type by cytologic and computed tomographic findings are reported. On computed tomograms, multiple, aggregated, small, and tiny cysts without a solid portion, along the lymphatic channels are characteristic computed tomographic findings for cavernous lymphangiomas.

Afferent loop obstruction after gastric cancer surgery: helical CT findings.

BACKGROUND: We reviewed the computed tomographic (CT) findings of afferent loop obstruction and assessed the value of helical CT in determining the underlying cause. METHODS: Helical CT scans of 18 patients (12 men and six women; age range = 35-67, mean age = 50 years) with afferent loop obstruction were reviewed. All patients had gastric cancer. Ten patients had undergone radical subtotal gastrectomy with Billroth II gastrojejunostomy, and eight had undergone total gastrectomy with Roux-en-Y esophagojejunostomy. CT images were analyzed retrospectively, and the presumed cause of obstruction on CT was compared with surgical findings (n = 8) and clinical courses (n = 10). RESULTS: Local recurrence (n = 15), peritoneal seeding (n = 1), internal hernia (n = 1), and adhesion (n = 1) were the presumed causes of obstruction on CT. In all eight patients who underwent a second operation, the cause of afferent loop obstruction was correctly suggested on CT (local recurrence in six patients and adhesion and internal hernia in one patient). In 10 patients who were not re-explored, the clinical findings or biopsy indicated recurrent tumor as suggested on CT. CONCLUSION: Recurrent tumors and other potential causes of afferent loop obstruction can be correctly predicted with CT in most cases.

Abdominal amyloidosis: spectrum of radiological findings.

Amyloidosis is a disease characterized by the deposition of fibrillar protein amyloid of beta-structure in organs or tissues. It is usually classified as either a primary disease or secondary to a co-existent condition, such as rheumatoid arthritis, tuberculosis, or neoplasm (particularly multiple myeloma or renal cell carcinoma). Amyloid protein deposition can be seen in a variety of organs though it occurs with higher frequency in the gastrointestinal tract, kidney, and heart. Amyloidosis can have a wide spectrum of manifestations in nearly every abdominal organ. Some of these, for example, multiple cystic submucosal masses of the stomach, amyloidosis of the gallbladder, and dirty soft tissue infiltration of the subcutaneous fat, have not yet been covered in the radiological literature. The combination of various imaging techniques and the identification of characteristic computed tomography (CT) hepatic features may help in the differentiation of amyloidosis from other infiltrative diseases; however, confirmative diagnosis can usually only be achieved by tissue biopsy.

Comparison of MR imaging with PET and ictal SPECT in 118 patients with intractable epilepsy.

BACKGROUND AND PURPOSE: MR imaging, PET, and ictal SPECT have been studied extensively as individual techniques in the localization of epileptogenic foci, but only a few comparative studies have been done. We evaluated the concordance rates of ictal video/EEG, MR imaging, PET, and ictal SPECT to compare the sensitivities of these imaging methods in the lateralization of epileptogenic foci. METHODS: The study included 118 consecutive patients who underwent surgery for medically intractable epilepsy and who were followed up for 12 months or more. MR imaging was compared retrospectively with ictal video/EEG, FDG-PET, ictal 99mTc-HMPAO SPECT, and invasive EEG as to their ability to localize the epileptogenic focus; the pathologic findings served as the standard of reference. RESULTS: MR imaging was concordant with video/EEG, PET, and ictal SPECT in 58%, 68%, and 58% of patients, respectively. With the pathologic diagnosis as the standard of reference, MR imaging, PET, and ictal SPECT correctly lateralized the lesion in 72%, 85%, and 73% of patients, respectively. Of the patients with good outcomes, MR imaging, PET, and ictal SPECT were correct in 77%, 86%, and 78%, respectively. In the good outcome group, MR imaging was concordant with PET and ictal SPECT in 73% and 62% of patients, respectively. Of 45 patients who underwent invasive EEG, MR imaging was concordant with the invasive study in 47%; PET in 58%; and ictal SPECT in 56%. Of 26 patients with normal MR findings, PET and ictal SPECT correctly lateralized the lesion in 80% and 55%, respectively. CONCLUSION: Overall concordance among the techniques is approximately two thirds or less in lateralizing epileptogenic foci. PET is the most sensitive, even though it provides a broad approximate nature of the epileptogenic zone, which is not adequate for precise surgical localization of epilepsy. PET and/or ictal SPECT may be used as complementary tools in cases of inconclusive lateralization with ictal video/EEG and MR imaging.

Experimental hepatobiliary fascioliasis in rabbits: a radiology-pathology correlation.

RATIONALE AND OBJECTIVES: The authors sought to correlate the radiologic findings of hepatobiliary fascioliasis with pathologic features. METHODS: Serial ultrasound, computed tomography (CT), and magnetic resonance findings in seven rabbits with experimentally induced fascioliasis were obtained every other week. Direct cholangiogram was also obtained after the rabbits were killed. Radiology-pathology correlation was done in specimens. RESULTS: In the parenchymal phase (an acute phase of parenchymal invasion of a larva), CT showed subcapsular clustered areas of low attenuation. Magnetic resonance appearance was similar in shape but better than CT in characterizing the hemorrhagic nature of the lesion. Ultrasound findings were nonspecific in this phase. In the ductal phase (a stationary phase after residing in the bile duct), CT showed dilatation of central ducts with symmetric periportal hypoattenuation (periportal tracking). Magnetic resonance could not depict mild ductal dilatation. Ultrasound was most valuable in demonstrating the moving worm within the dilated duct. Pathologically, the hepatic parenchymal lesions consisted of a cluster of eosinophilic granulomas with hemorrhagic change (migratory tract of the flukes). Ductal changes were observed predominantly in the central bile ducts. Periportal lymphangiectasia was also noted. CONCLUSIONS: Computed tomography or magnetic resonance can demonstrate the characteristic evolutionary pattern of fascioliasis that reflects the unique life cycle of Fasciola hepatica. The role of ultrasound, although limited in the parenchymal phase, was most useful in the ductal phase in that it demonstrated the moving worms themselves.

Invasive pulmonary aspergillosis: prediction at thin-section CT in patients with neutropenia--a prospective study.

PURPOSE: To evaluate prospectively the usefulness of thin-section computed tomography (CT) in the prediction of biopsy-proved invasive pulmonary aspergillosis in patients with neutropenia. MATERIALS AND METHODS: In 11 consecutively seen neutropenic patients, 12 open-lung biopsies were performed prospectively for suspected angioinvasive (n = 10) or airway-invasive (n = 2) pulmonary aspergillosis. Thin-section CT findings in the patients with angioinvasive pulmonary aspergillosis were reviewed, and the findings were compared with those of other diseases. RESULTS: Five of 12 biopsy specimens were positive for angioinvasive pulmonary aspergillosis; none was positive for airway-invasive pulmonary aspergillosis. In five (50%) of 10 cases, suspicion of angioinvasive pulmonary aspergillosis proved to be correct. The most common CT findings were segmental areas of consolidation plus ground-glass attenuation (four of five cases [80%]) and at least one nodule surrounded by a halo (two of five cases [40%]). Segmental areas of consolidation plus ground-glass attenuation were seen as isolated findings in three and mixed findings with nodules that have a surrounding halo in one case. In two patients, at least one nodule with a halo was an isolated finding in one patient and a mixed finding in one patient. Mucormycosis, organizing pneumonia, and pulmonary hemorrhage produced similar findings. CONCLUSION: At thin-section CT, segmental areas of consolidation plus ground-glass attenuation or at least one nodule with the halo sign were seen in patients with invasive pulmonary aspergillosis. The findings were nonspecific, however, and can be seen in neutropenic patients with mucormycosis, organizing pneumonia, or pulmonary hemorrhage.

Intratumoral vascularity of experimentally induced VX2 carcinoma: comparison of color Doppler sonography, power Doppler sonography, and microangiography.

RATIONALE AND OBJECTIVES: Tumor vascularity is useful for characterizing tumors and determining tumor management. The recent development of power Doppler sonography has enhanced the sensitivity of color Doppler imaging in the detection of blood flow because of low power noise and less angle dependence. The purpose of this study was to compare the capability of color and power Doppler sonography with that of microangiography for showing tumor vascularity of VX2 carcinoma. METHODS: Color and power Doppler sonography was performed on VX2 carcinomas in the rabbit thighs, and their findings were correlated with those of microangiography. For qualitative analysis, tumor vascularity was categorized into four items including distribution of tumor vessels, crowdedness of vessels, small vessels, (> or = 0.1 mm), and micro-vessels (< 0.1 mm). Tumor blood flow signals of color Doppler sonography and power Doppler sonography were graded as 3, 2, 1, and 0 and were compared with tumor vascularity on microangiography. For quantitative analysis, percentages of tumor vascular area per tumor area on each study were compared. RESULTS: The mean scores of tumor vascularity on power Doppler sonography were 2.87, 2.73, 2.93, and 2.73 in tumor vascular distribution, crowdedness of vessels, small vessels, and micro-vessels, respectively. Those on color Doppler sonography were 2.4, 2.2, 2.8, and 1.67, respectively. Power Doppler sonography was statistically superior to color Doppler sonography in displaying tumor vascular distribution (P < 0.05) and micro-vessels (P < 0.01). The means and medians of percentages of tumor vascular area per tumor area were 22.7% and 23.5% on microangiography, 17.9% and 21.4% on color Doppler sonography, and 36.4% and 34.7 % on power Doppler sonography, respectively. Percentages of tumor vascular area per tumor area on both color Doppler sonography (r = 0.70) and power Doppler sonography (r = 0.84) were well correlated with those on microangiography. CONCLUSIONS: Power Doppler sonography can demonstrate the tumor vascularity on microangiography relatively well, however, it tends to overestimate the blood flow signals. Color Doppler sonography may have some limitations in imaging tumor vascular distribution and micro-vessels and tends to underestimate tumor vascularity, but can display the blood flow direction. Therefore, power Doppler and color Doppler sonography could complement each other in demonstrating the tumor vascularity.