Hepatic parenchymal enhancement in the cirrhotic liver: evaluation by triple-phase dynamic MRI

Evaluation of Liver Fibrosis Using Texture Analysis on Combined-Contrast-Enhanced Magnetic Resonance Images at 3.0T

Purpose. To noninvasively assess liver fibrosis using combined-contrast-enhanced (CCE) magnetic resonance imaging (MRI) and texture analysis. Materials and Methods. In this IRB-approved, HIPAA-compliant prospective study, 46 adults with newly diagnosed HCV infection and recent liver biopsy underwent CCE liver MRI following intravenous administration of superparamagnetic iron oxides (ferumoxides) and gadolinium DTPA (gadopentetate dimeglumine). The image texture of the liver was quantified in regions-of-interest by calculating 165 texture features. Liver biopsy specimens were stained with Masson trichrome and assessed qualitatively (METAVIR fibrosis score) and quantitatively (% collagen stained area). Using L₁ regularization path algorithm, two texture-based multivariate linear models were constructed, one for quantitative and the other for quantitative histology prediction. The prediction performance of each model was assessed using receiver operating characteristics (ROC) and correlation analyses. Results. The texture-based predicted fibrosis score significantly correlated with qualitative (r = 0.698, P < 0.001) and quantitative (r = 0.757, P < 0.001) histology. The prediction model for qualitative histology had 0.814–0.976 areas under the curve (AUC), 0.659–1.000 sensitivity, 0.778–0.930 specificity, and 0.674–0.935 accuracy, depending on the binary classification threshold. The prediction model for quantitative histology had 0.742–0.950 AUC, 0.688–1.000 sensitivity, 0.679–0.857 specificity, and 0.696–0.848 accuracy, depending on the binary classification threshold. Conclusion. CCE MRI and texture analysis may permit noninvasive assessment of liver fibrosis.

Pediatric hepatobiliary magnetic resonance imaging

Magnetic resonance (MR) imaging is an effective and noninvasive modality for evaluating hepatobiliary pathologic conditions. This article provides an up-to-date review of anatomy, indications, and imaging goals and protocols, including patient preparation, pulse sequences, and contrast agents used in pediatric MR hepatobiliary imaging. This article also highlights some of the common MR features of pediatric liver pathologic conditions, including tumors, congenital biliary ductal plate malformations, trauma, fibrosis, and infection.

Gadobenate dimeglumine-enhanced liver MR imaging in cirrhotic patients: quantitative and qualitative comparison of 1-hour and 3-hour delayed images

PURPOSE

To compare the image quality and diagnostic performance of 1- and 3-h delayed-phase MR images (DPIs) after gadobenate dimeglumine injection in detecting small hepatocellular carcinomas (HCCs) in cirrhotic patients.

MATERIALS AND METHODS

Relative enhancement of the liver (RE(liver) ) and HCC (RE(HCC) ) and liver-to-lesion contrast-to-noise ratio (CNR) of HCC were measured quantitatively on 1- and 3-h DPIs in 65 patients with 88 HCCs. For qualitative analysis, two radiologists independently evaluated three image sets in 19 patients with 25 HCCs ≤ 2 cm and in 16 controls without HCCs: conventional liver MR without DPI (set A), adding 1-h DPI (set B), and adding 3-h DPI (set C), using a 5-point scale for diagnosing small HCCs. Diagnostic performance for small HCCs was analyzed using the alternative free-response receiver operating characteristic method.

RESULTS

Mean RE(liver) (P = 0.013) and RE(HCC) (P < 0.001) were significantly higher on 1-h than on 3-h DPI, whereas CNR was significantly higher on 3-h than on 1-h DPI (P = 0.001). Observer-averaged figure of merit (FOM) was significantly higher for set C than for set A (0.942 versus 0.883; P = 0.013).

CONCLUSION

In cirrhotic patients, 3-h DPI provides a higher liver-to-lesion contrast and a better diagnostic performance for small HCCs than 1-h DPI.

MRI of the liver--how to do it

This article details indications, patient preparation, pulse sequences/protocols, and contrast agents for pediatric hepatobiliary MRI. When performed well, MRI provides superior diagnostic information relative to CT for evaluation of hepatic tumors, liver transplants, and biliary disease.

Can imaging modalities diagnose and stage hepatic fibrosis and cirrhosis accurately?

The accurate diagnosis and staging of hepatic fibrosis is crucial for prognosis and treatment of liver disease. The current gold standard, liver biopsy, cannot be used for population-based screening, and has well known drawbacks if used for monitoring of disease progression or treatment success. Our objective was to assess performance and promise of radiologic modalities and techniques as alternative, noninvasive assessment of hepatic fibrosis. A systematic review was conducted. Six hundred twenty-eight studies were identified via electronic search. One hundred fifty-three papers were reviewed. Most described techniques that could differentiate between cirrhosis or severe fibrosis and normal liver. Accurate staging of fibrosis or diagnosis of mild fibrosis was often not achievable. Ultrasonography is the most common modality used in the diagnosis and staging of hepatic fibrosis. Elastographic measurements, either ultrasonography-based or magnetic resonance-based, and magnetic resonance diffusion weighted imaging, show the most promise for accurate staging of hepatic fibrosis. Most currently available imaging techniques can detect cirrhosis or significant fibrosis reasonably accurately. However, to date only magnetic resonance elastography has been able to stage fibrosis or diagnose mild disease. Utrasonographic elastography and magnetic resonance diffusion weighted appear next most promising.

MRI features of regenerative and dysplastic nodules in cirrhotic liver

AIM: To study MR features of the regenerative nodule (RN) and dysplastic nodule (DN) in the cirrhotic liver.

METHODS: MRI was performed in 26 cases of suspected cirrhotic liver with RN and DN. Additional enhanced MRI with administration of Gd-DTPA on T1WI was performed in 18 of 26 cases. Meanwhile in 10 of 18 both Gd-DTPA and SPIO (Feridex) enhancement were underwent one day apart. All patients were confirmed by aspiration biopsy or histopathology. MRI was compared to the pathological findings.

RESULTS: In 26 cases, there were 12 cases of regenerative nodules measuring 0.3-1cm in size, and 14 dysplastic nodules including 8 nodules measuring ≥1 cm and <3 cm in size, and 6 nodules measuring ≥3 cm. Their MR appearances were as followings: nodules with <1 cm in size showed isointensity on T₁WI and hypointensity on T₂WI, of which the intensity was as isointense as the surrounding hepatic parenchyma on enhanced MRI with administration of Gd-DTPA or SPIO. In 8 cases with nodules measuring 1-3 cm in size, 5 cases appeared hyperintense on T1WI and hypointense on T₂WI as well as the enhancement as that of nodules with <1 cm in size; the other 3 cases appeared hypointense on T₁WI and hyperintense on T₂WI, and were enhanced after administration of Gd-DTPA but hyperintense on SPIO enhancing MRI, which indicated malignant transformation of dysplastic nodule into hepatocellular carcinoma (HCC) arising from hepatic nodule on histopathology. In 6 cases of nodules measuring >3 cm in size, 2 cases appeared hyperintense compared to the surrounding hepatic parenchyma on T₁, T₂WI and enhanced MRI, one of which was documented "nodule within a nodule" on T₂WI. The 2 cases were demonstrated well-differentiated HCC. The other 4 cases showed hyperintense on T1WI, and hypointense on T₂WI and enhanced MRI. Sometimes, normal vessels were seen to pass through the surface of macroregenerative nodule. Additionally, RN and DN had the same pattern of the time-signal intensity course as the normal surrounding hepatic parenchyma, but malignant transformation of DN appeared fast wash-in and wash-out.

CONCLUSION: RN of cirrhosis has features on MRI that usually allow distinction from HCC but not always from DN. A helpful distinction between HCC and DN is that the latter is almost never hyperintense on T₂WI. Additionally, the followings indicate malignant transformation of DN when DN appears a ring like enhancement after injection of Gd-DTPA, and fast wash-in and wash-out as well as hyperintensity on SPIO enhanced MRI.