Detection of small hypervascular hepatocellular carcinomas in cirrhotic patients: comparison of superparamagnetic iron oxide-enhanced MR imaging with dual-phase spiral CT

Computed tomography for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease

BACKGROUND

Hepatocellular carcinoma occurs mostly in people with chronic liver disease and ranks sixth in terms of global incidence of cancer, and fourth in terms of cancer deaths. In clinical practice, computed tomography (CT) is used as a second-line diagnostic imaging modality to confirm the presence of focal liver lesions suspected as hepatocellular carcinoma on prior diagnostic test such as abdominal ultrasound or alpha-foetoprotein, or both, either in surveillance programmes or in clinical settings. According to current guidelines, a single contrast-enhanced imaging study CT or magnetic resonance imaging (MRI) showing typical hallmarks of hepatocellular carcinoma in people with cirrhosis is valid to diagnose hepatocellular carcinoma. However, a significant number of hepatocellular carcinomas do not show typical hallmarks on imaging modalities, and hepatocellular carcinoma is, therefore, missed. There is no clear evidence of the benefit of surveillance programmes in terms of overall survival: the conflicting results can be a consequence of inaccurate detection, ineffective treatment, or both. Assessing the diagnostic accuracy of CT may clarify whether the absence of benefit could be related to underdiagnosis. Furthermore, an assessment of the accuracy of CT in people with chronic liver disease, who are not included in surveillance programmes is needed for either ruling out or diagnosing hepatocellular carcinoma.

OBJECTIVES

Primary: to assess the diagnostic accuracy of multidetector, multiphasic contrast-enhanced CT for the diagnosis of hepatocellular carcinoma of any size and at any stage in adults with chronic liver disease, either in a surveillance programme or in a clinical setting. Secondary: to assess the diagnostic accuracy of CT for the diagnosis of resectable hepatocellular carcinoma in adults with chronic liver disease.

SEARCH METHODS

We searched the Cochrane Hepato-Biliary Trials Register, Cochrane Hepato-Biliary Diagnostic-Test-Accuracy Studies Register, the Cochrane Library, MEDLINE, Embase, LILACS, Science Citation Index Expanded, and Conference Proceedings Citation Index - Science until 4 May 2021. We applied no language or document-type restrictions.

SELECTION CRITERIA

Studies assessing the diagnostic accuracy of CT for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease, with cross-sectional designs, using one of the acceptable reference standards, such as pathology of the explanted liver and histology of resected or biopsied focal liver lesion with at least a six-month follow-up.

DATA COLLECTION AND ANALYSIS

At least two review authors independently screened studies, extracted data, and assessed the risk of bias and applicability concerns, using the QUADAS-2 checklist. We presented the results of sensitivity and specificity, using paired forest plots, and tabulated the results. We used a hierarchical meta-analysis model where appropriate. We presented uncertainty of the accuracy estimates using 95% confidence intervals (CIs). We double-checked all data extractions and analyses.

MAIN RESULTS

We included 21 studies, with a total of 3101 participants. We judged all studies to be at high risk of bias in at least one domain because most studies used different reference standards, often inappropriate to exclude the presence of the target condition, and the time-interval between the index test and the reference standard was rarely defined. Regarding applicability in the patient selection domain, we judged 14% (3/21) of studies to be at low concern and 86% (18/21) of studies to be at high concern owing to characteristics of the participants who were on waiting lists for orthotopic liver transplantation. CT for hepatocellular carcinoma of any size and stage: sensitivity 77.5% (95% CI 70.9% to 82.9%) and specificity 91.3% (95% CI 86.5% to 94.5%) (21 studies, 3101 participants; low-certainty evidence). CT for resectable hepatocellular carcinoma: sensitivity 71.4% (95% CI 60.3% to 80.4%) and specificity 92.0% (95% CI 86.3% to 95.5%) (10 studies, 1854 participants; low-certainty evidence). In the three studies at low concern for applicability (861 participants), we found sensitivity 76.9% (95% CI 50.8% to 91.5%) and specificity 89.2% (95% CI 57.0% to 98.1%). The observed heterogeneity in the results remains mostly unexplained. The sensitivity analyses, which included only studies with clearly prespecified positivity criteria and only studies in which the reference standard results were interpreted without knowledge of the results of the index test, showed no variation in the results.

AUTHORS' CONCLUSIONS

In the clinical pathway for the diagnosis of hepatocellular carcinoma in adults with chronic liver disease, CT has roles as a confirmatory test for hepatocellular carcinoma lesions, and for staging assessment. We found that using CT in detecting hepatocellular carcinoma of any size and stage, 22.5% of people with hepatocellular carcinoma would be missed, and 8.7% of people without hepatocellular carcinoma would be unnecessarily treated. For resectable hepatocellular carcinoma, we found that 28.6% of people with resectable hepatocellular carcinoma would improperly not be resected, while 8% of people without hepatocellular carcinoma would undergo inappropriate surgery. The uncertainty resulting from the high risk of bias in the included studies and concerns regarding their applicability limit our ability to confidently draw conclusions based on our results.

Imaging Techniques for the Diagnosis of Hepatocellular Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

Several imaging modalities are available for diagnosis of hepatocellular carcinoma (HCC).

PURPOSE

To evaluate the test performance of imaging modalities for HCC.

DATA SOURCES

MEDLINE (1998 to December 2014), the Cochrane Library Database, Scopus, and reference lists.

STUDY SELECTION

Studies on test performance of ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI).

DATA EXTRACTION

One investigator abstracted data, and a second investigator confirmed them; 2 investigators independently assessed study quality and strength of evidence.

DATA SYNTHESIS

Few studies have evaluated imaging for HCC in surveillance settings. In nonsurveillance settings, sensitivity for detection of HCC lesions was lower for ultrasonography without contrast than for CT or MRI (pooled difference based on direct comparisons, 0.11 to 0.22), and MRI was associated with higher sensitivity than CT (pooled difference, 0.09 [95% CI, 0.07 to 12]). For evaluation of focal liver lesions, there were no clear differences in sensitivity among ultrasonography with contrast, CT, and MRI. Specificity was generally 0.85 or higher across imaging modalities, but this item was not reported in many studies. Factors associated with lower sensitivity included use of an explanted liver reference standard, and smaller or more well-differentiated HCC lesions. For MRI, sensitivity was slightly higher for hepatic-specific than nonspecific contrast agents.

LIMITATIONS

Only English-language articles were included, there was statistical heterogeneity in pooled analyses, and costs were not assessed. Most studies were conducted in Asia and had methodological limitations.

CONCLUSION

CT and MRI are associated with higher sensitivity than ultrasonography without contrast for detection of HCC; sensitivity was higher for MRI than CT. For evaluation of focal liver lesions, the sensitivities of ultrasonography with contrast, CT, and MRI for HCC are similar.

PRIMARY FUNDING SOURCE

Agency for Healthcare Research and Quality. (

PROSPERO

CRD42014007016).

Recent advances in superparamagnetic iron oxide nanoparticles for cellular imaging and targeted therapy research

Advances of nanotechnology have led to the development of nanomaterials with both potential diagnostic and therapeutic applications. Among them, superparamagnetic iron oxide (SPIO) nanoparticles have received particular attention. Over the past decade, various SPIOs with unique physicochemical and biological properties have been designed by modifying the particle structure, size and coating. This article reviews the recent advances in preparing SPIOs with novel properties, the way these physicochemical properties of SPIOs influence their interaction with cells, and the development of SPIOs in liver and lymph nodes magnetic resonance imaging (MRI) contrast. Cellular uptake of SPIO can be exploited in a variety of potential clinical applications, including stem cell and inflammation cell tracking and intra-cellular drug delivery to cancerous cells which offers higher intra-cellular concentration. When SPIOs are used as carrier vehicle, additional advantages can be achieved including magnetic targeting and hyperthermia options, as well as monitoring with MRI. Other potential applications of SPIO include magnetofection and gene delivery, targeted retention of labeled stem cells, sentinel lymph nodes mapping, and magnetic force targeting and cell orientation for tissue engineering.

Transarterial chemoembolization for the treatment of hepatocellular carcinoma: a single center experience including 221 patients

BACKGROUND

Hepatocelluar carcinoma (HCC) is a major health problem in Egypt as well as in many countries. Transarterial chemoemoblization (TACE) is a treatment modality applicable to locally advanced HCC beyond surgery or ablative therapies and is associated with survival improvements. The aim of this study was to assess the outcomes of TACE in our center over the past four years.

METHODS

This is a retrospective cohort study that included 221 patients with locally advanced HCC treated with TACE in a single center between the years 2007 and 2010. The median age was 57 years with male predominance. Liver cirrhosis, viral hepatitis and Bilharziasis were encountered in 64%, 31% and 8% of patients, respectively. Abdominal pain was the most common presenting symptom (67%). Most cases were diagnosed based on radiology (57%) with a TNM stage I or II (73%) and a median AFP value of 150 ng/mL.

RESULTS

221 patients received 440 cycles of TACE with a median of 2 cycles per patient. Cisplatin and doxorubicin (50mg per cycle, each) were the most commonly used drugs. Impaired liver function was the most common toxicity. Liver cell failure occurred in 17% of patients. An objective tumor response was achieved in 44% of cases. The median overall survival (OS) was 16 months (95% CI, 13-19 months) and the median progression free survival (PFS) was 6 months (95% CI, 4.3-7.8 months). Responding patients, Child-Pugh class A and patients receiving standard doses of chemotherapy had a significantly better OS than their counterparts. Only Child-Pugh class A was associated with significantly longer PFS (p < 0.001).

CONCLUSION

TACE produces reasonable responses and fair survival rates in locally advanced HCC but with noticeable toxicities. Proper patients' selection and prompt liver support are mandates for improving TACE outcomes.

Superparamagnetic iron oxide based MRI contrast agents: Current status of clinical application

Superparamagnetic iron oxide (SPIO) MR contrast agents are composed of nano-sized iron oxide crystals coated with dextran or carboxydextran. Two SPIO agents are clinically approved, namely: ferumoxides (Feridex in the USA, Endorem in Europe) with a particle size of 120 to 180 nm, and ferucarbotran (Resovist) with a particle size of about 60 nm. The principal effect of the SPIO particles is on T2* relaxation and thus MR imaging is usually performed using T2/T2*-weighted sequences in which the tissue signal loss is due to the susceptibility effects of the iron oxide core. Enhancement on T1-weighted images can also be seen with the smaller Resovist. Both Feridex and Resovist are approved specifically for MRI of the liver. The difference being that Resovist can be administered as a rapid bolus (and thus can be used with both dynamic and delayed imaging), whereas Feridex needs to be administered as a slow infusion and is used solely in delayed phase imaging. In the liver, these particles are sequestered by phagocytic Kupffer cells in normal reticuloendothelial system (RES), but are not retained in lesions lacking Kupffer cells. Consequently, there are significant differences in T2/T2* relaxation between normal tissue and lesions, resulting in increased lesion conspicuity and detectability. SPIO substantially increase the detectability of hepatic metastases. For focal hepatocellular lesions, SPIO-enhanced MR imaging exhibits slightly better diagnostic performance than dynamic CT. A combination of dynamic and static MR imaging technique using T1- and T2 imaging criteria appears to provide clinically more useful patterns of enhancement. Feridex and Resovist are also used for evaluating macrophage activities in some inflammatory lesions, but their clinical values remain to be further confirmed. The clinical development of Ferumoxtran (Combidex in the USA, Sinerem in Europe), designed for lymph node metastasis evaluation, is currently stopped.

CT and MRI of hepatocellular carcinoma: an update

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and one of the few malignancies with an increasing incidence in the USA. Imaging plays a crucial role in early detection, accurate staging and planning management strategies. Contrast material-enhanced MRI or computed tomography (CT) are the best imaging techniques currently available for the noninvasive diagnosis of HCC. The diagnosis of HCC is strongly dependent on hemodynamic features (arterial hypervascularity and washout in the venous phase) on dynamic imaging, and biopsy is no longer recommended for tumors with classical imaging features prior to treatment. The major challenge for radiologists in imaging cirrhosis is the characterization of hypervascular nodules smaller than 2 cm, which often have nonspecific imaging characteristics. In this review, we discuss the role of CT and MRI in the diagnosis and staging of HCC. The strengths and current limitations of these imaging modalities are highlighted.

Nanotechnology and MRI contrast enhancement

Technical advances in nanotechnology are creating novel classes of MRI contrast-enhancing agents. These nanomaterials offer much higher relaxivities than most current clinical contrast agents, which translates into greater MRI contrast enhancement. These nanoscale agents also have the potential to revolutionize in vivo applications of contrast-enhanced MRI since they offer the multiple advantages of low toxicities, extremely high relaxivities and cell internalization capabilities. In this review, we discuss three types of such contrast agents currently in use or under development for medical imaging: small particles of iron oxide, fullerenes encapsulating Gd3+ ions (gadofullerenes) and single-walled carbon nanotube nanocapsules encapsulating Gd3+ ion clusters (gadonanotubes). The latest developments and projected future applications of these nanotechnology-inspired contrast agents in the field of medical imaging are also discussed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

The current practice of transarterial chemoembolization for the treatment of hepatocellular carcinoma

Despite remarkable advancement in the surveillance and treatment of hepatocellular carcinoma (HCC) and the availability of novel curative options, a great proportion of HCC patients are still not eligible for curative treatment due to an advanced tumor stage or poor hepatic functional reserve. Therefore, there is a continuing need for effective palliative treatments. Although practiced widely, it has only recently been demonstrated that the use of transarterial chemoembolization (TACE) provides a survival benefit based on randomized controlled studies. Hence, TACE has become standard treatment in selected patients. TACE combines the effect of targeted chemotherapy with the effect of ischemic necrosis induced by arterial embolization. Most of the TACE procedures have been based on iodized oil utilizing the microembolic and drug-carrying characteristic of iodized oil. Recently, there have been efforts to improve the delivery of chemotherapeutic agents to a tumor. In this review, the basic principles, technical issues and complications of TACE are reviewed and recent advancement in TACE technique and clinical applicability are briefed.

Small malignant hepatic tumor detection in gadolinium- and ferucarbotran-enhanced magnetic resonance imaging: does combining ferucarbotran-enhanced T2*-weighted gradient echo and T2-weighted turbo spin echo images have additive efficacy?

Objective

To determine if a combination of ferucarbotran-enhanced T2^*weighted-gradient echo (T2^*W-GRE) and T2-weighted turbo spin echo (T2W-TSE) images in gadolinium- and ferucarbotran-enhanced MRI has additive efficacy compared to each image alone for detecting small (≤ 2.0 cm) hepatocellular carcinoma (HCC) lesions in a group of cirrhotic patients and metastases in a group of non-cirrhotic patients.

Materials and Methods

Two readers retrospectively analyzed gadolinium- and ferucarbotran-enhanced T2^*W-GRE, T2W-TSE, and combined T2^*W-GRE/T2W-TSE images of 119 patients with 157 HCCs and 32 patients with 98 metastases. The diagnostic accuracy and sensitivity for each image set and the combined set were evaluated using the alternative-free response receiver operating characteristic method.

Results

The mean area under the curve value of the combined set (0.966) tended to be better than that for each individual image set (T2W-TSE [0.910], T2^*W-GRE [0.892]). Sensitivities in the combined set were higher than those in each individual image set for detecting HCC (mean, 93.0% versus 81.6% and 86.7%, respectively, p < 0.01). Sensitivities in the combined set and the T2W-TSE set were the same for detecting metastases, and both were higher than the sensitivity seen in the T2^*W-GRE set (mean, 97.5% versus 85.2%, p < 0.01).

Conclusion

Combining ferucarbotran-enhanced T2^*W-GRE and T2W-TSE has additive efficacy for detecting HCC in cirrhotic patients, but T2W-TSE is preferred for detecting metastases in non-cirrhotic patients.

Ferucarbotran-enhanced T2-weighted magnetic resonance imaging: differentiation of hepatic cavernous hemangiomas from malignant solid lesions

BACKGROUND

To demonstrate the characteristic feature of hepatic cavernous hemangiomas on ferucarbotran-enhanced T2-weighted MR imaging as a new diagnostic finding.

METHODS

In 201 hepatic lesions (61 hemangiomas, 61 cysts, 41 hepatocellular carcinomas, 31 metastatic carcinomas, and 7 cholangiocarcinomas), lesion-to-liver contrast on ferucarbotran-enhanced T2-weighted images was qualitatively compared with pre-contrast images by three independent readers using a four-grade scale (group 1, marked increase; group 2, mild increase; group 3, no change; group 4, decrease). The change in the contrast-to-noise ratio (CNR) for each lesion was quantitatively measured.

RESULTS

Only hemangiomas showed a significant decrease in CNR; 10% and 90% of the hemangiomas were categorized as group 3 and 4 lesions, respectively. Besides the hemangiomas, there was no other lesion categorized into group 4 except for one cyst. When group 4 lesions were considered hemangiomas, the accuracy of identification was 96.4%.

CONCLUSION

Hemangiomas show a significant decrease in lesion-to-liver contrast on T2-weighted images after ferucarbotran injection, which might be another typical diagnostic imaging finding of hemangiomas distinguished from solid malignant lesions.

Follow-up result afters negative findings on unenhanced hepatic MR imaging for hepatic metastasis from rectal cancer

OBJECTIVE

To assess the follow-up results after negative findings on unenhanced hepatic MR imaging in rectal cancer patients who have undergone locally curative surgery.

MATERIALS AND METHODS

From all pertinent imaging reports and medical records, we selected 255 patients who had negative results on unenhanced hepatic MR imaging. When selecting patients who had undergone curative resection, the following patients were excluded from the study: 1) patients in whom extrahepatic metastases were detected on preoperative staging work-ups, 2) patients in whom the surgery was judged to be non-curative due to peritoneal seeding or local aggressiveness. Cases with follow-up periods of less than 18 months were also excluded, as these cases were considered insufficient to confirm the negative outcomes. Thus, a total of 149 patients were ultimately enrolled in our study. The follow-up results of unenhanced MR imagings were assessed according to the assumption that the newly developed hepatic metastases had been false-negative lesions on preoperative MR image.

RESULTS

During a median follow-up period of 29.3 months, 25 hepatic metastases were detected in 13 patients (8.7%), which indicated a negative predictive value of 91.3%.

CONCLUSION

Unenhanced hepatic MR imaging provides a high negative predictive value with regard to the detection of hepatic metastasis in the preoperative evaluation of rectal cancer.

Superparamagnetic iron oxide-enhanced liver magnetic resonance imaging: comparison of 1.5 T and 3.0 T imaging for detection of focal malignant liver lesions

OBJECTIVES

We sought to compare the image quality, lesion conspicuity, and the diagnostic performance of 1.5 T and 3.0 T superparamagnetic iron oxide-enhanced liver magnetic resonance imaging (MRI) for detecting focal malignant hepatic lesions.

MATERIALS AND METHODS

A total of 35 patients with pathologically proven liver malignancy underwent both 1.5 and 3.0 T SPIO-enhanced MRI. The diagnostic accuracy was evaluated using the alternative-free response receiver operating characteristic method. Image artifacts, quality, and the lesion conspicuity were analyzed. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the lesion were calculated.

RESULTS

No significant difference of area under ROC curve (Az value) was noted. The mean SNR and CNR of the lesions was higher in the 3.0 T sets. There was no difference between the 1.5 T and the 3.0 T image sets for lesion conspicuity, but the image quality was better on 1.5 T. Motion and susceptibility artifacts were more frequent on 3.0 T.

CONCLUSION

Diagnostic accuracies of the SPIO-enhanced MRI were equivalent on the 1.5 T and 3.0 T image sets. More prominent artifacts on 3.0 T superparamagnetic iron oxide-enhanced liver MRI counteracted advantage of higher SNR and CNR of 3.0 T.

Application of superparamagnetic iron oxide to imaging of hepatocellular carcinoma

Superparamagnetic iron oxide (SPIO) particles are as MR contrast media composed of iron oxide crystals coated with dextran or carboxydextran. These particles are sequestered by phagocytic Kupffer cells in normal reticuloendothelial system (RES), but are not retained in tumor tissue. Consequently, there are significant differences in T2/T2* relaxation between normal RES tissue and tumors, which result in increased lesion conspicuity and detectability. The introduction of SPIO has been expected to substantially increase the detectability of hepatic metastases. For focal hepatocellular lesions, it has been documented that SPIO-enhanced MR imaging exhibits slightly better diagnostic performance than dynamic helical CT in the detection of hypervascular hepatocellular carcinoma (HCC). A combination of dynamic and static MR imaging technique using T1- and T2 imaging criteria appears to provide clinically more useful patterns of enhancement. SPIO-enhanced MR imaging also provides information useful for differential diagnosis, via enhancement of RES-containing tumors. With the exploitation of rapid T2*-sensitive sequences, SPIO-enhanced dynamic MR imaging may become comparable to gadolinium-enhanced dynamic MR imaging and dynamic studies with multidetector-row CT. SPIO-enhanced MR imaging plays an important role in therapeutic decision-making for patients with HCC.

Hepatocellular carcinoma in patients with chronic liver disease: comparison of SPIO-enhanced MR imaging and 16-detector row CT

PURPOSE

To compare the sensitivity, positive predictive value, and diagnostic accuracy of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance (MR) imaging with those of 16-detector row computed tomography (CT) for the detection of hepatocellular carcinoma (HCC) in patients with hepatitis B-induced cirrhosis.

MATERIALS AND METHODS

Institutional Review Board approval was obtained for this study, and informed consent was obtained from all patients. A total of 44 patients (36 men, eight women; age range, 35-67 years) with 59 HCCs and mild liver cirrhosis (Child-Pugh score A or B) underwent multiphasic CT and SPIO-enhanced MR imaging. The diagnosis of HCC was established at surgical resection (n = 31) and percutaneous biopsy (n = 28). SPIO-enhanced MR imaging was composed of T2-weighted turbo spin-echo and T2*-weighted gradient-echo sequences. Multiphasic CT consisted of four phases (ie, early arterial, late arterial, portal venous, and equilibrium). Three observers independently analyzed each image in random order. Sensitivity, positive predictive value, and diagnostic accuracy were calculated by using the alternative free-response receiver operating characteristic analysis for multi-detector row CT and SPIO-enhanced MR imaging.

RESULTS

Although not significant (P > .05), the area under the receiver operating characteristic curve for SPIO-enhanced MR imaging (mean, 0.90) was higher than that for multi-detector row CT (mean, 0.82) for all observers. Also, although no significant difference was demonstrated by any of the three observers (P > .05), there was a trend toward increased sensitivity on both a per-lesion and a per-patient basis for SPIO-enhanced MR imaging (mean, 84.7% and 94.7%, respectively) compared with multi-detector row CT (mean, 76.9% and 88.6%, respectively). No significant difference in positive predictive value was observed between modalities.

CONCLUSION

SPIO-enhanced MR imaging and multiphasic CT show similar diagnostic accuracy, sensitivity, and positive predictive value for the detection of HCC in patients with relatively mild hepatitis B-induced cirrhosis.

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

OBJECTIVE

We compared ferucarbotran-enhanced MRI with triple-phase MDCT for the preoperative detection of hepatocellular carcinoma.

SUBJECTS AND METHODS

Seventy-three consecutive patients with 121 hepatocellular carcinomas underwent ferucarbotran-enhanced MRI, including a dynamic study, and triple-phase MDCT before hepatic resection. The diagnosis of hepatocellular carcinoma was confirmed in all patients by means of pathologic examination after surgical resection. Three experienced radiologists independently reviewed the MR and CT images on a segment-by-segment basis. The accuracy of these techniques for the detection of hepatocellular carcinoma was assessed by conducting a receiver operating characteristic (ROC) analysis of the observations of 88 resected hepatic segments with at least one hepatocellular carcinoma each and 121 resected hepatic segments without hepatocellular carcinoma.

RESULTS

The mean values of the area under the ROC curve (A(z)) for ferucarbotran-enhanced MRI and triple-phase MDCT for all observers were 0.947 and 0.949, respectively; the difference between these two values was not statistically significant (p = 0.799). The mean sensitivities of MRI and triple-phase MDCT were 90.2% and 91.3%, respectively, and their mean specificities were 97.0% and 95.3%, respectively. The differences in the mean sensitivities and specificities of these two imaging techniques were not statistically significant (p > 0.05 in each case).

CONCLUSION

Ferucarbotran-enhanced MRI seems to be as accurate as triple-phase MDCT for the preoperative detection of hepatocellular carcinoma.

Imaging the liver

Imaging of the liver is undertaken for the detection and characterization of suspected primary or secondary neoplasms, prior to planning a surgery or chemotherapy pump placement, for assessing treatment response, for evaluating biliary pathology, and for screening for liver neoplasms in high-risk groups. In this article, we review the advantages and disadvantages of various imaging modalities in the evaluation of the liver and formulate guidelines for the imaging of common clinical indications. A brief review of imaging findings in focal and diffuse liver disease is also presented.