AJR in Brief continues on p. 20
Current State-of-the-Art MRI
for Comprehensive Evaluation
of Potential Living Liver
The current state-of-the-art MRI
techniques, when used in combination with other imaging modalities,
play an important role for an all-in-one, comprehensive, preoperative
evaluation of potential living donors.
The study was conducted by a team of
researchers from the joint department
of medical imaging, University of Health Network at the
University of Toronto.
According to the team’s research, since the first adult-to-adult
transplantation of a right liver lobe in 1994, the number of living-donor liver transplants has increased dramatically with good results. These outcomes are similar to those of cadaver liver
transplantation. As a result, guiding a safe harvest of the graft
from donors, which includes an accurate preoperative evaluation
of potential living liver donors for conditions that increase the
donor’s surgical risk, is crucial. The imaging evaluation includes
the following four aspects: ( 1) hepatic vascular anatomy, ( 2) biliary anatomy, ( 3) the degree of hepatic steatosis, and ( 4) the size
of the liver volume.
For hepatic vascular anatomy, gadobenate dimeglumine– or gadoxetic disodium–enhanced MR angiography is good enough for
most patients, although CT angiography is still needed for a few
cases where the arterial phase is suboptimal. For biliary anatomy,
a combined use of T2-weighted MR cholangiography (MRC) and
gadoxetic disodium–enhanced T1-weighted MRC has evolved as a
noninvasive surrogate for ERCP and CT cholangiogram. For hepatic steatosis, MRI or MR spectroscopy techniques are helpful to
reduce the liver biopsy needs for donor candidates.
Four-Dimensional Flow MRI-
Based Splenic Flow Index for
A splenic flow index that incorporates both splenic volume and blood
flow is a better indicator of cirrhosis-associate hypersplenism than is splenic volume alone, according to a study
that involved 39 patients ( 14 women
and 25 men) with cirrhosis and sequel-ae of portal hypertension.
Cirrhosis-associated hypersplenism is a common complication of cirrhosis and portal hypertension that can have serious
clinical consequences secondary to cytopenia, particularly
thrombocytopenia and leukopenia. The common clinical understanding of this condition has been that cirrhosis leads to portal
hypertension that causes splenic hypertrophy with increased
platelet pooling and consumption.
MRI and MR spectroscopy techniques are
helpful to reduce the liver biopsy needs for
donor candidates.—Kartik S. Jhaveri
Kartik S. Jhaveri
The authors used unenhanced 4D-flow MRI and contrast-enhanced T1-weighted gradient-recalled echo imaging, in addition to the laboratory values of the patients, to investigate
relationships between splenic volume, blood flow, and blood
component counts. They also assessed whether the use of these
variables alone or a metric that combines these variables could
best predict hypersplenism.
In conclusion, the study showed that increased splenic volume, blood flow, and portosystemic shunts in the setting of cirrhosis and portal hypertension correlate with hypersplenism but
offer inferior predictive power compared with an unenhanced,
4D-flow, MRI–based splenic flow index that combines these factors. Unenhanced 4D-flow MRI coupled with anatomic imaging
has the ability to noninvasively determine the clinical significance of splenomegaly in the setting of cirrhosis and thrombocytopenia while providing valuable hemodynamic information for
Demonstrates Unique Regional
Brain Stiffness Patterns in
MR Elastography (MRE) shows a
unique, disease-specific, age-corrected,
MRE is increasingly being investigated to measure brain
stiffness in a variety of neurologic diseases including dementia,
a clinical disorder with symptoms characterized by progressive
deterioration in different cognitive domains. MRE is a noninvasive technique capable of quantitatively measuring tissue stiffness in vivo. It is a three-step process that begins with the
The study showed that increased splenic
volume, blood flow, and portosystemic
shunts in the setting of cirrhosis and portal
hypertension correlate with hypersplenism.
John Huston, III