ANATOMICAL MARKERS FOR DIVIDING LIVER INTO LOBES

1..All the anatomic markers serve to divide the right lobe from the left lobe except

a.the intrahepatic IVC

b.the gall bladder fossa

c.the middle hepatic vein

d.the undivided portion of the right portal vein

e.falciparum ligament

1..---e

2..All are true regarding imaging of anatomy of liver except

a.the longest branch of the right hepatic vein divides the right lobe into anterior and posterior segment

b. the falciform ligament divides the left lobe into medial and lateral segment

c.IVC divides thecaudate lobe from the lateral segment of the left lobe

d.accessary fissure of liver is formed by the vagnationations of the diaphragm and peritoneum

e.the right lobe and medial segment of the left lobe is resected in trisegmentectomy

2---c

The longest branch of the right hepatic vein and bifurcation of the right portal vein divides the right lobe into anterior and posterior segment.

The left hepatic vein(cranial part),ascending  portion of the left portal vein(middle part) and the falciform ligament(caudal part ) divides the left lobe into medial and lateral segment

The fissure of the venous ligament divides the caudate lobe from the lateral segment of the left lobe

HEPATIC RESECTION

1.1.A patients has hepatic metastases from a endocrine tumour and surgeon plans to resect the liver to palliate the symptoms due to metastases . What % of liver parenchyma should the surgeon spare  for hepatic function to be adequate in postoperative stage

a.20%

b.30%

c.40%

d.50%

e.60%

1.---b

HEPATIC IMAGING

8.All are true regarding imaging of liver except

a.segmental anatomy on dynamic CT is more readily  depicted in fatty liver

b.portal vein and hepatic veins are  hypodense to normal parenchyma on delayed CT

c. portal vein and hepatic veins are  hypodense to normal parenchyma on CTAP

d.hepatic deposits are hypodense to normal parenchyma on CTAP

e.Sensitivity of CTAP is greater than MRI in detecting focal lesions

8.---c

 Portal vein and hepatic veins are  hyperdense to normal parenchyma on CTAP.

Hepatic deposits are hypodense to normal parenchyma on CTAP because hepatic deposits receive blood supply primarily from hepatic artery.

Sensitivity of CTAP is greater than dynamic CT,delayed CT and  MRI in detecting focal lesions and so it is pre-operative choice of imaging

AASLD CRITERIA FOR HCC

Q.All are true regading AASLD criteria for diagnosis of HCC in cirrhosis except

a.use of multiphasic CT/MRI

b.arterial hyperattenuation of lesion

c.portal venous phase hypoattenation of thelesion

d.delayed phase hyperatenuation of the lesion

e.portal veous phase /delayed phase washout

ANS.---d

The radiologic diagnosis of hepatocellular carcinoma can be made at either CT or MR imaging, provided that a multiphasic contrast material–enhanced study is used.

Characteristically, hepatocellular carcinoma enhances during the arterial phase because of its blood supply from abnormal hepatic arteries. Contrast medium in the surrounding liver parenchyma is diluted during this phase because the parenchymal blood supply arises mostly from the portal veins, which are not yet opacified.

 In the portal venous phase, the surrounding liver parenchyma becomes relatively hyperattenuated and the lesion is perceived to be hypoattenuated because of its lack of portal venous supply. This appearance is the so-called washout effect. Occasionally, washout is evident only during a delayed phase sequence. 

Thus, a four-phase imaging study is required: non–contrast-enhanced phase, arterial phase, portal venous phase, and delayed phase

  Images should be acquired in four phases: non–contrast-enhanced phase (before the injection of contrast material), late arterial phase (about 20 seconds after the injection), portal venous phase (50 seconds after the injection), and delayed phase (>120 seconds after the injection). The optimal timing for image acquisition in the delayed phase is debated, varying between 2 and 15 minutes after contrast material injection. Contrast-enhanced US studies have shown that approximately 90% of hepatocellular carcinomas demonstrate washout by 5 minutes after injection of the microbubble contrast agent . Use of a 5-minute delay may be the practical choice for the timing of the delayed phase.

Precontrast and dynamic postcontrast T1-weighted three-dimensional fat-suppressed gradient-echo sequences are required, in addition to T2 (with and without fat saturation) and T1 in-phase and opposed-phase imaging. Timing of the dynamic contrast-enhanced sequences is the same as that used for the CT examination. Emphasis on precise breath-holding is extremely important.

Systematic review has shown that MR imaging is more sensitive than CT in the diagnosis of hepatocellular carcinoma (81% vs 68%)