Role of Cross-Sectional Imaging in Diagnosis and Treatment of Hepatocellular Carcinoma

Running head: ESSAY
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ESSAY1
Introduction- Hepatocellular carcinoma (HCC) refers to the most prevalent
primary live cancer that is reported among adults, and has been identified as one of the major
contributing factors to mortality to patients who have been diagnosed with cirrhosis. HCC
primarily occurs in relation to chronic liver inflammation, and is associated with the onset
and progress of chronic viral hepatitis infection (hepatitis C or B), in addition to exposure of
patients to toxins such as aflatoxin or alcohol (Galle et al. 2018). Certain illnesses, such as,
alpha 1-antitrypsin deficiency and hemochromatosis, markedly increase the possibility of
developing HCC. Some other risk factors that have been associated with an increased risk of
HCC include metabolic syndrome and NASH. Also referred to as Nonalcoholic
steatohepatitis, the condition is characterised by inflammation of the liver, followed by its
damage, and an accumulation of fat in the liver. Most instances of HCC are reported by
individuals who already manifest signs and symptoms of chronic infection in the liver (Bruix,
Reig and Sherman 2016). Some notable signs that help healthcare professionals to diagnose
the illness are yellow skin, loss of appetite, abdominal swelling, easy bruising, and abdominal
pain. This essay will critically evaluate the role of cross-sectional imaging scan in the
diagnosis and treatment of HCC.
Discussion- The diagnostic imaging technique of computed tomography scan, also
referred to as CT scan utilises the computer-processed arrangements of numerous X-ray
measurements that have been obtained from diverse angles to generate cross-sectional and/or
tomographic virtual "slices", commonly known as images of particular areas of the scanned
body part (Manesh 2009). The primary reason for using CT to observe the anatomical
structures of the body can be accredited to the fact that it eliminates the need for
superimposing images of body parts surround the regions outside the main area that is being
visualised (Seeram 2009). Furthermore, owing to the characteristic high-contrast resolution
obtained in a CT image, variances between the tissues that differ in their physical density by

ESSAY2
not more than 1% can be easily eminent. Eventually, information obtained from a single CT
comprises of either multiple adjacent or a single helical scan that can be observed in three
orthogonal planes namely, the coronal, axial, or sagittal planes, contingent on the diagnostic
procedure. In contrast, magnetic resonance imaging or MRI is used to visualise the
anatomical structures based on the radio frequency that is emitted from the equipment
(Jhankaria 2011). Similar to CT, MRI imaging leads to the generation of a two-dimensional
thin "slice", thus proving effective as a tomographic imaging method (Wang 2012).
Lee et al. (2015) tried to determine the diagnostic performance of a mutidetector CT
and MRI for HCC and performed a systematic review, followed by subsequent meta-analysis
for the same. The methodology of the study was accurate since it helped the researchers
obtain comprehensive information between the two imaging modalities, thus facilitating a
comparison about the effectiveness. On conducting an extensive search of electronic
databases namely, EMBASE, MEDLINE, and Cochrane Library they could retrieve 40
studies of which 22 on MRI, six were on multidetector CT, and 12 on both MRI and CT. The
findings suggested that of the total 1135 and 2489 patients who had been subjected to CT and
MRI, respectively, the general per-patient sensitivity of MRI was found to be 88% (95% CI:
83%, 92%), and also reported a specificity of 94% (95% CI: 85%, 98%). Furthermore, MRI
had a higher complete per-lesion sensitivity, in contrast to CT, on pooling the data obtained
from 11 studies (80% vs 68%, P = .0023). Further role of MRI in diagnosing HCC was
elucidated by the significantly increased higher per-lesion sensitivity that was obtained on
conducting MRI with gadoxetic acid, in comparison to other contrasting agents (87% vs
74%, P = .03), thereby making the researchers accurately conclude that MRI is a better cross-
sectional imaging modality for observing HCC, in patients who have been diagnosed with the
chronic liver disease.

ESSAY3
Part I of HCC was diagnosed and staged by the aforementioned two cross-sectional
imaging procedures namely, MRI and CT in another trial conducted by Choi, Lee and Sirlin
(2014). The researchers were accurate in focusing their investigation on the background
information that prognosis of HCC largely depends on the phase when a tumour is spotted.
Furthermore, patients manifesting HCC symptoms usually have a dismal prognosis, owing to
the fact that HCC typically does not generate symptoms beyond the underlying liver disease,
till the condition has become incurable. The explanations that supported the images obtained
from the diagnostic procedure suggested that extracellular contrast agents facilitate HCC
diagnosis based mostly on the physiologic variations that occur in intranodular blood flow
accompanying hepatocarcinogenesis. With the aim of comprehensively evaluating these
vicissitudes, multiphasic inspections are accomplished with attainment of imageries earlier
(precontrast) and after administration of the contrast agent. On varying the dose of MRI
contrast agent from 0.025-0.1 mmol gadolinium/kilogram, the image produced highlights
three enhanced stages namely, (i) late hepatic arterial, (ii) portal venous, and (iii) delayed
phase. MRI images suggest that during the late hepatic phase, the hepatic artery gets
completely enhanced due to anterograde flow that overlaps with liver tumour enhancement
and peak arterial perfusion, thus helping in characterisation and detection of hypervascular
HCC. The images also highlighted that on administering 0.1 mmol/kg gadobenate
dimeglumine, HCC can be easily diagnosed by MRI based on both hepatocellular function
and vascularity. The researchers also illustrated that use of hepatobiliary agents helped in
generation of image that contained a strongly enhanced hepatic parenchyma owing to the
intrahepatocellular uptake that is OATP-mediated, which eventually enhances the large bile
ducts because of biliary excretion, thus causing hypoenhancement of the blood vessels.