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Query: UMLS:C1864663 (HCC)
 2,985 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Dependence on T1 contrast can be reduced by changing the excitation flip angle. Low flip-angle spin-echo imaging can reduce imaging time because repetition time (TR) is reduced. The authors assessed the efficacy of low flip-angle spin-echo images in phantoms and in liver. MR phantoms made from polyvinyl alcohol gel to model the properties of normal liver, HCC, and hemangioma were scanned with various flip angles at TR 2400 and 1200 msec. Measured signal intensities fitted well with theoretical values. The T1 contrast of signal intensity decreased as the flip angle was reduced, accompanied by a decrease in signal-to-noise ratio (S/N). Thirty patients with hepatic space-occupying lesions (23 with HCC, three with metastases and four with hemangioma) were studied by conventional SE (CSE) at 2400/60/2 (TR/TE/NEX [number of excitations]) (10 min 46 sec imaging time) and low flip-angle SE (LFSE) at 1200/60/30 degrees/2 (TR/TE/FA/NEX) (5:20) and/or 1200/60/30 degrees/4 (10:18). The sensitivity of CSE in detecting lesions was 93% (44/47). It was 92% (35/38) for LFSE with two NEX and 94% (34/36) for LFSE with four NEX pulse sequences. The contrast-to-noise ratio (C/N) for images (HCC/liver, hemangioma/liver) obtained by LFSE with four NEX was significantly higher than that for those obtained by CSE (4.8 vs 3.5, p less than 0.01; 13.4 vs 9.7, p less than 0.01, respectively). Although the C/N (lesion/liver) for LFSE with two NEX sequences was lower than that of CSE for any type of lesion (3.0 vs 3.5 for HCC; 5.1 vs 6.3 for metastases; 8.3 vs 9.7 for hemangioma), the difference was not significant. Although reducing the flip angle from 90 degrees to 30 degrees with two NEX resulted in a decrease in S/N (10.7 to 8.9 for HCC; 15.3 to 11.9 for metastases; 20.0 to 18.1 for hemangioma; 7.4 to 6.3 for normal liver; 10.7 to 10.1 for spleen), the difference was not significant. For hepatic space-occupying lesions, low flip-angle spin-echo imaging is useful to obtain T2-weighted images in a shorter imaging time without sacrificing lesion detectability.
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PMID:[Low flip-angle spin-echo imaging of the liver. Basic study and its application to hepatic space-occupying lesions]. 165 32

With a retrospective analysis of images from 39 patients with histologically proven liver tumours we tried to determine the best MRT-parameter for detection of cavernous hemangioma (n = 19) and its differentiation from malignoma (metastases n = 17, HCC n = 5). The best differentiation was achieved with the contrast-to-noise ratio between lesion and liver in multi-echo-images with TR/TE = 2,000/210 ms and a definite limit with an accuracy of 84% for hemangioma and 91% for malignoma. The respective intensity ratios (lesion/liver) were 95% and 77%. T2-relation times and the T1- and T2-ratios were also calculated. In contrary to the literature we think that these parameters are not sufficiently discriminating.
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PMID:[Differential diagnosis by MRT of cavernous hemangiomas and malignant tumors of the liver--advantages of the multi-echo technic]. 216 Jun 68

In a retrospective study the findings of dynamic CT investigations in 185 patients with histologically confirmed hepatic masses were analysed and related to 47 criteria which have been described in the literature. The criteria with the highest value for making a specific diagnosis have been defined for seven different lesions (abscess, adenoma, FNH, haemangioma, adenocarcinoma metastases, metastases from other tumours, HCC). We found agreement with the literature in the following: the target phenomenon for abscesses, central scarring for FNH, spreading enhancement for haemangiomas and irregularity of the liver contour in the absence of subcapsular tumours for HCC. By combining a number of criteria it was possible to suggest the type of lesion retrospectively. The predictive value was found to range from 73% to 100%, a definite diagnosis was possible in only 64%.
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PMID:[A frequency analysis and evaluation of the criteria for dynamic CT and a test of the CT diagnosis of space-occupying lesions of the liver]. 217 14

Nodular hepatic lesions detected in 123 patients with chronic liver diseases were subjected to ultrasonically guided needle biopsy. Of these, 94 cases were diagnosed as hepatocellular carcinoma of a moderately or poorly differentiated type with classical histologic features of hepatocellular carcinoma. In 14 cases in whom hepatocytes had minimal atypical changes and were mostly of normotrabecular arrangement (one to two cells thick), a diagnosis of well-differentiated hepatocellular carcinoma was made on the basis of the following three histologic criteria: nuclear crowding, increased cytoplasmic basophilia and microacinar formation. The nodules which showed two or more of these findings were diagnosed as well-differentiated HCC. The diagnoses of these 14 cases were subsequently confirmed by clinical course, histology in the resected specimen and/or autopsy findings. The nodules that presented similar but equivocal changes were arbitrarily categorized as borderline lesions (five cases). The nodules showing the findings almost identical with those of pseudolobules were regarded as benign, large regenerative nodules (nine cases). The remaining one case had a hemangioma. Thus, these three histologic criteria proved to be useful in the biopsy diagnosis of nodular hepatic lesions, with certain limitations. Additionally, the majority of large regenerative nodules, borderline lesions and well-differentiated HCCs were found to be smaller than 2 cm.
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PMID:Biopsy diagnosis of well-differentiated hepatocellular carcinoma based on new morphologic criteria. 254 84

This study was aimed at assessing the accuracy of Magnetic Resonance Imaging (MRI) in the characterization of focal liver masses. We prospectively examined 51 patients with focal liver masses: the morphological features were investigated with different pulse sequences and the functional characteristics were studied after the i.v. administration of Gd-DTPA (2 mmol/kg). MR findings were compared with those of gold standard methods, i.e., percutaneous biopsy, surgery or, for hemangiomas, 99mTc-labelled blood cell liver scintigraphy. All hemangiomas presented with typical features: signal intensity was very high on long TE images (> 140 msec) and a globular enhancement pattern, with centripetal progression, was observed after dynamic studies. This signal pattern on T2-weighted images is highly indicative of hemangioma. Five of 7 focal nodular hyperplasias (71%) were isointense with hepatic parenchyma on all pulse sequences; the central scar was observed in 5/7 cases on short TR/TE images and in all cases on long TR/TE images in 16/17 cases (94%). High signal intensity on T1-weighted images was statistically significant for HCC. A pseudocapsule was observed in 12 cases (70%). A mosaic pattern on T2-weighted images was observed in 3 cases. Seventy-four per cent of HCCs exhibited signal enhancement during the arterial phase of the dynamic study. Metastases presented a uniform pattern, i.e., they were hypointense on T1-weighted and hyperintense on T2-weighted images in 12/13 cases (92%). A central hypointense area on T2-weighted images is indicative of coagulative necrosis. A lesion with these morphological features and hypovascular signal is suggestive of metastasis.
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PMID:[The tissue characterization of focal liver lesions with magnetic resonance imaging]. 750 30

CO2 gas-enhanced ultrasonography was performed in 37 patients (47 studies) for the purpose of detecting small tumors and evaluating differential diagnosis. With conventional ultrasonography, 62 lesions were identified in 25 patients with HCC, 13 tumors were identified in eight patients with hemangioma, and multiple tumors were found in four patients with metastatic adenocarcinoma. CO2-enhanced ultrasonography detected five additional hemangiomas, 12 additional nodules in HCC, and the same number of metastatic nodules. The patterns of CO2 enhancement were characterized as homogeneous, heterogeneous, rim, internal spotted, negative, and mixed (more than one pattern in one lesion). The rim enhancement pattern was found to be specific for hemangioma. The internal spotted enhancement pattern was found exclusively in HCC. All the lesions that demonstrated negative enhancement were treated HCC. All the metastatic tumors demonstrated the mixed rim and internal spotted enhancement pattern. We suggest that CO2-enhanced ultrasonography is a useful tool in detecting small liver tumors. It can also help in the differentiation among various hepatic tumors.
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PMID:Carbon dioxide-enhanced ultrasonography of liver tumors. 793 65

Ultrasonic frequency-dependent attenuation (FDA) coefficients of the liver obtained from selected regions of interest within the liver were determined in 106 individuals, 40 cases presumed normal based on medical histories and 66 with malignant tumors (hepatocellular carcinoma [HCC] or metastatic liver tumor) or benign tumors (hepatic hemangioma, hepatic adenoma, or focal nodular hyperplasia of the liver). All liver tumors were confirmed histopathologically by ultrasonically guided fine-needle biopsy and/or operation. Mean attenuation of normal liver was 0.53 +/- 0.03 dB/cm/MHz, 0.29 +/- 0.05 dB/cm/MHz in hepatic hemangioma, 0.43 +/- 0.05 dB/cm/MHz in HCC, and 0.41 +/- 0.12 dB/cm/MHz in metastatic liver tumor. Hepatic adenoma and focal nodular hyperplasia of the liver produced higher values, averaging 0.66 +/- 0.09 dB/cm/MHz. This difference between malignant and benign tumors was statistically significant. There was some correlation between the FDA for the hepatic tumor and the histopathology that merits further investigation.
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PMID:In vivo measurements of frequency-dependent attenuation in tumors of the liver. 816 36

This study was undertaken to compare the detection rate of hepatic space occupying lesion (SOL)s between computed tomography during arterial portography (CT-AP) and magnetic resonance imaging during arterial portography (MR-AP) and the differences in time intensity curve on MR-AP between HCC, metastatic tumor, FNH, and hemangioma. We performed CT-AP and MR-AP in 17 patients including 14 cases of HCC and one each of metastasis, FNH, and hemangioma. MR-AP was performed by Turbo-FLASH sequence. There was no statistically significant difference between CT-AP and MR-AP in detecting satellite lesions in terms of smallest diameter and number of flow defects (p > 0.05). Hemangioma showed rapid enhancement after the first pass and, consequently, the same enhancement as the hepatic parenchyma. MR-AP was comparable to CT-AP in the detection of hepatic SOLs. Hemangioma showed an enhancement pattern different from those of HCC, metastatic tumor, and FNH, which showed patterns similar to each other.
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PMID:MR imaging during arterial-portography (MR-AP) in the detection of hepatic tumor: comparison with CT-AP. 949 85

The usefulness of two-phase helical computed tomography (CT) of the liver was evaluated in clinical cases. First, an optimal scanning protocol was determined using time-attenuation analysis. Monophasic dynamic CT was performed with 100 ml of contrast media (iodine 300 mg/ml) injected either at 3 ml/s or at 2 ml/s. Aortic, hepatic and portal time-attenuation curves were made for each protocol. The results showed that these two different injection protocols produce equivalent enhancements and that the injection rate of 2 ml/s is satisfactorily applicable to clinical cases. The first scanning (arterial phase) must be started 40-45 s after the beginning of the injection of contrast media and the second scanning (delayed phase) 80-120 s after the beginning of injection. Using these CT protocols, 327 cases were examined. In this study 83 hepatic lesions (hepatocellular carcinoma : HCC, n = 29; suspected HCC, n = 30; hemangioma, n = 24) were evaluated. There were 15 HCCs smaller than 30 mm in diameter (71.4%) detected by either arterial phase or delayed phase alone. This result indicates that two-phase helical hepatic CT is very useful in the detection of small HCC. Particularly, four of 5 HCCs of less than 10 mm in size (80%) showed a hyperattenuation area in the arterial phase alone. HCCs which have sufficient vascularity were also easily demonstrated. However, this two-phase helical hepatic CT could not demonstrate 11 lesions (13.3%) with almost normal blood supply. In such cases the complementary role of ultrasound (US) seems to be important. Hence as a screening of hepatic mass lesions both CT and US are necessary. Most HCC could be differentiated from hemangioma by an enhancement pattern using this protocol. But the small liver lesions of less than 15 mm in size with homogeneous hyperattenuation in the arterial phase and isoattenuation in the delayed phase included HCC, hemangioma and metastatic tumors.
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PMID:[Two-phase helical hepatic CT. Contrast-injection protocol, optimal timing and its usefulness in clinical cases]. 955 26

The use of helical CT, infusing pump and non-ionic contrast media has enabled the evaluation of different hepatic circulatory phases during contrast injection. Starting the acquisition of scans 20 to 30 seconds after the injection at a rate of 3 to 4 ml/sec the arterial enhancing of the liver is depicted. THROMBOSIS OR COMPRESSION OF THE PORTAL VEIN: Hypervascular triangle-shaped was with peripheral base can be seen, secondary to the increased arterial flow to compensate for the diminished portal flow. ARTERIOPORTAL SHUNTS: This condition can be caused by tumors such hepatocellular adenocarcinomas and hemangiomas, trauma, interventional procedures, cirrhosis, AVMs and surgery. INFLAMMATORY LESIONS: Hypervascular areas can be seen during the arterial phase in abscesses or cholecystitis, returning to their normal condition in the arterial phase. ANATOMIC VARIANTS: Third veins coming from the periphery (capsular veins, accessory cystic vein and an aberrant gastric vein) supply enhanced blood earlier than the portal circulation. OTHER CAUSES: In liver cirrhosis diffuse hyperattenuated areas can be seen during the arterial circulation. In right-sided heart failure, pericardial disease and Budd-Chiari Syndrome, "mosaic areas" can also be noted. In other patients these perfusion disorders were considered unknown. TUMORS: The well-differentiated hepatocellular carcinoma is a lesion with a predominant arterial blood supply, thus appearing in general hyperdense in this phase. Hemangiomas may appear as highly hyperdense lesions in the arterial phase and can be misinterpreted as HCC if smaller than 2 cm. (30% of cases). Focal nodular hyperplasia is a benign lesion (vascular malformation associated with focal nodules of hepatocellular hyperplasia) with increased arterial blood supply. Hepatic adenomas show an important hypervascularity during the arterial phase and, if large, they may present a small central scar and or capsule. Low or high-grade dysplastic nodules can sometimes be seen as hypervascular areas during the arterial phase. Although most metastasis are depicted as hypodense lesions sometimes they can show arterial hypervascularity such as carcinoid and pancreatic islet cell metastasis.
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PMID:[Liver hyperdensity during arterial phase on CT exams]. 1147 23


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