1. Imaging Approach for Evaluation of Focal Liver Lesions
Daniele Marin, Alessandro Furlan, Michael P. Federle, Massimo Midiri, Giuseppe Brancatelli 
Clinical Gastroenterology and Hepatology 
Volume 7, Issue 6, Pages (June 2009)
DOI: /j.cgh
Copyright © 2009 AGA Institute Terms and Conditions

2. Figure 1
Suggested algorithm for the investigation of patients with incidental focal liver lesions. HCC, hepatocellular carcinoma. *Diagnostic work-up of incidentally discovered focal hepatic lesions in patients with cirrhosis is based on the data-supported recommendations endorsed by the American Association for the Study of the Liver Diseases.33 **Lesion enhancement during the HAP, followed by washout (decreased attenuation relative to the liver) during the HVP and/or delayed phase as shown by a single (lesions >2 cm) or 2 (lesions 1–2 cm) different imaging modalities.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

3. Figure 2
Images obtained in a 69-year-old man with HCV-related cirrhosis and hepatocellular carcinoma (HCC). (A) Transverse contrast-enhanced CT scan obtained during the HAP shows an ill-defined area of minimal enhancement (arrow) of undetermined etiology in the left liver lobe. Compared with CT, sagittal contrast-enhanced (B) US and (C) transverse MR images during the HAP reveal a 1.5-cm vividly enhancing lesion (arrows) that was a small HCC.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

4. Figure 3
Effect of contrast media injection rate on the conspicuity of enhancement of focal liver lesions on contrast-enhanced CT during the HAP. (A) Transverse contrast-enhanced CT scan after rapid (4 mL/s) contrast medium injection in a 22-year-old man with focal nodular hyperplasia demonstrates bright and homogeneous enhancement of a 2.0-cm lesion (curved arrow) in the right liver lobe. Note the vivid enhancement of the aorta (asterisk), portal vein (black arrow), spleen (S), and left kidney (K), as well as the absence of enhancement of the hepatic veins (white arrows). These findings are imaging hallmarks of a properly timed HAP. (B) On corresponding CT image during the HVP, the lesion becomes isoattenuating compared with the adjacent liver. (C) Transverse contrast-enhanced CT scan after slow (1 mL/s) contrast medium injection in a 40-year-old woman with focal nodular hyperplasia demonstrates barely visible enhancement of a 5.0-cm lesion (arrows) in the left liver lobe. Note the characteristic central hypoattenuating scar (curved arrow).
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

5. Figure 4
Images obtained in a 58-year-old man with HCV-related cirrhosis and hepatocellular carcinoma. (A) Transverse contrast-enhanced CT scan obtained during the early HAP without monitoring the contrast bolus circulation time demonstrates suboptimal timing (noted by absent enhancement of the portal vein [arrow] and spleen [S]). No arterial enhancing lesion can be identified. (B) Corresponding transverse MR image during the appropriate HAP performed with a bolus tracking technique (Smartprep; GE Healthcare, Chalfont St Giles, UK) reveals a 2.0-cm vividly enhancing hepatocellular carcinoma (curved arrow) in the right liver lobe.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

6. Figure 5
Images obtained in a 58-year-old man with hepatic metastases from adenocarcinoma of the colon. (A) Transverse contrast-enhanced CT scan obtained during the HVP demonstrates a 1.0-cm hypoattenuating metastatic lesion (arrow) in the right hepatic lobe. Note homogeneous enhancement of the hepatic veins (curved arrow) as well as parenchymal organs such as the liver, spleen, and kidneys, all imaging hallmarks of a properly timed HVP. (B) On the corresponding image obtained during the HAP, this lesion was not detected because it was isoattenuating to the surrounding liver.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

7. Figure 6
Image obtained in a 69-year-old man with HCV-related cirrhosis and hepatocellular carcinoma. Maximum intensity projection coronal CT image obtained during the HAP shows a 3.5-cm vividly enhancing lesion (straight arrow) receiving blood supply from an arterial branch of the left hepatic artery (curved arrow) originating from the left gastric artery. Knowing the arterial anatomy is crucial for treatment planning for patients who might be candidates for transarterial hepatic chemoembolization.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

8. Figure 7
Images obtained in a 58-year-old man with cirrhosis, hepatocellular carcinoma, and acute onset of abdominal pain. (A) Transverse noncontrast CT scan shows a 4.0-cm lesion (straight arrows) in the left liver lobe, with a focal area of inherently higher attenuation (curved arrow) caused by intralesional hemorrhage. (B, C) Corresponding contrast-enhanced CT scans during (B) the HAP and (C) HVP demonstrate classic enhancement pattern of hepatocellular carcinoma characterized by moderate heterogeneous enhancement during the arterial phase, followed by rapid washout during the HVP. Note that the area of intratumoral hemorrhage is not visible after contrast material administration.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

9. Figure 8
Images obtained in a 78-year-old woman with HCV-related cirrhosis and hepatocellular carcinoma. (A) Transverse noncontrast CT scan shows a 3.5-cm lesion in the left lobe, with a focal area (curved arrow) of inherently lower attenuation (–50 HU) caused by intralesional fat deposition. (B, C) On corresponding dual gradient echo MR sequence with (B) in-phase (IP) and (C) opposed-phase (OP) acquisitions, the lesion's fat component (curved arrows) demonstrates marked signal intensity decrease on OP compared with IP image as a result of chemical shift artifact from intracellular fat.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

10. Figure 9
Images obtained in a 70-year-old woman with hepatic metastases from breast carcinoma. (A) Transverse contrast-enhanced CT scan obtained during the HVP shows 2 mildly hypoattenuating subcapsular lesions (arrows) of 2.5 cm (segment IVa) and 1 cm (segment II). Note diffusely decreased attenuation of the liver parenchyma as a result of fatty liver disease caused by systemic chemotherapy (more evident on nonenhanced CT, not shown). (B, C) Corresponding T1-weighted and fat-suppressed T2-weighted MR images demonstrate increased conspicuity of the lesions (arrows), which show low signal intensity on (B) T1-weighted and (C) high signal intensity on T2-weighted images compared with the adjacent liver. Notably, although both tumors were identified on MRI, the smaller lesion was prospectively missed on CT.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

11. Figure 10
MR images obtained in an asymptomatic 29-year-old woman with focal nodular hyperplasia. (A) Transverse, fat-suppressed, T1-weighted 3-dimensional spoiled gradient-echo gadobenate dimeglumine-enhanced MR image during the HAP shows a 6.0-cm vividly and homogeneously enhancing lesion (arrows) with a central hypointense scar. These findings are highly suggestive of focal nodular hyperplasia. (B) On a corresponding image obtained during the liver-specific phase (120 minutes after contrast administration), the lesion demonstrates mildly higher signal intensity compared with the surrounding liver as a result of active hepatobiliary excretion of contrast medium. This finding is indicative of preserved hepatic function and impaired biliary drainage of the lesion, as typically seen in focal nodular hyperplasia, and enabled a differential diagnosis with classically nonenhancing hepatic adenoma.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

12. Figure 11
CT images obtained in a 58-year-old woman with ductal adenocarcinoma of the breast. (A) Transverse contrast-enhanced CT scan obtained during the HVP shows a small hypoattenuating lesion (arrow) in left hepatic lobe that was deemed too small to characterize. (B) On corresponding contrast-enhanced CT scan performed 5 months later, this lesion remains unchanged in size and appearance (white arrow); however, there is a second 1.0-cm lesion (black arrow), which was not detected on the previous CT examination, with peripheral rim enhancement and central hypoattenuation. At 2-year follow-up (not shown), the smaller lesion remained stable in size and appearance and was therefore of benign nature, whereas the larger lesion reduced in size as a consequence of systemic chemotherapy.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

13. Figure 12
Images obtained in a 70-year-old woman with breast carcinoma and multiple biliary hamartomas mistaken for hepatic metastases. (A) Transverse contrast-enhanced CT obtained during the HVP at an outside institution demonstrates multiple hypoattenuating lesions (from 0.2 to 2.0 cm) (arrows) that were regarded as suggestive for hepatic metastases, partially because of volume averaging artifacts as a result of the use of thick section thickness (10 mm) during the CT acquisition. (B) Corresponding fat-suppressed T2-weighted MR image demonstrates very high signal intensity of these lesions (arrows), which, along with the large number and small size of the lesions, suggested the correct diagnosis of biliary hamartomas.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

14. Figure 13
CT images obtained in a 67-year-old man with HCV-related cirrhosis and hepatocellular carcinoma. (A, B) Transverse contrast-enhanced CT obtained during (A) the HAP and (B) HVP shows a 2.0-cm lesion with contrast washout during the venous phase (arrow) but no evidence of enhancement during the arterial phase. This lesion was proved to be a well-differentiated hepatocellular carcinoma, although imaging findings could also be consistent with large regenerative or dysplastic nodule.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

15. Figure 14
MR images obtained in an 85-year-old woman with hepatocellular carcinoma and tumor seeding along the needle tract after radiofrequency ablation. Transverse, fat-suppressed, T1-weighted 3-dimensional spoiled gradient-echo gadobenate dimeglumine-enhanced MR image during the HAP shows a 2.0-cm homogeneously enhancing nodule (curved arrow) in the subcutaneous fat of the anterior abdominal wall that corresponds to the puncture site of the radiofrequency electrode.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

16. Figure 15
CT images obtained in a 74-year-old woman with hepatocellular carcinoma who underwent radiofrequency ablation. (A) Transverse contrast-enhanced CT scan obtained during the HAP shows a 3.5-cm lesion (arrows) in left hepatic lobe. (B) On corresponding image obtained 1 month after the ablation procedure, the lesion demonstrates uniform hypoattenuation caused by tumor necrosis, except for a peripheral enhancing nodule indicative of residual vital tumor tissue (curved arrow). On the basis of the latter finding, the patient underwent repeat radiofrequency ablation procedure with successful tumor ablation, shown on a subsequent scan (C).
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions

17. Figure 16
Images obtained in a 78-year-old man with hepatocellular carcinoma who underwent transcatheter arterial chemoembolization. (A) Transverse contrast-enhanced CT scan obtained during the HAP shows homogeneous accumulation of high attenuation iodized oil (Lipiodol; Guerbet, Aulnay-sous-Bois, France) (arrow) within the tumor, which prevents the assessment of intralesional residual tumor tissue. (B) Corresponding transverse, fat-suppressed T1-weighted 3-dimensional spoiled gradient-echo gadobenate dimeglumine-enhanced MR image during the HAP demonstrates a peripheral, irregular rim of vividly enhancing viable tumor (curved arrow) that is now easily detected as a result of the absence of Lipiodol-related MRI artifacts.
Clinical Gastroenterology and Hepatology 2009 7, DOI: ( /j.cgh )
Copyright © 2009 AGA Institute Terms and Conditions