A Feasibility Study to Assess the Use of Gadolinium in Computed Tomography
| Status: | Not yet recruiting |
|---|---|
| Healthy: | No |
| Age Range: | 20 - Any |
| Updated: | 4/2/2016 |
| Start Date: | March 2015 |
| End Date: | December 2018 |
| Contact: | Amita Sharma, MD |
| Email: | asharma2@partners.org |
| Phone: | 6177244254 |
Gadolinium Enhanced Dual-Energy Computed Tomography: A Feasibility Study to Assess Image Quality and Diagnostic Confidence
Patients with an allergy to iodine based intravenous contrast cannot undergo a CT scan with
contrast, unless they are premedicated. Premedication can result in a delay in diagnosis,
that can be significant with acute conditions such as Pulmonary embolism.
The investigators are evaluating the use of Gadolinium as an alternative contrast agent in
CT. Gadolinium has been used extensively in MRI exams but the dose that is used is not
sufficient to provide good enhancement on CT. Dual Energy CT is a new technology that has
better sensitivity to lower doses of intravenous contrast and the investigators aim to study
its effectiveness in improving the enhancement with Gadolinium. The investigators will
compare enhancement of Iodine with enhancement of Gadolinium during Dual Energy CT, to
assess the possibility that Gadolinium could be used as an alternative for patients who are
suspected of having Pulmonary embolism. They will recruit up to 50 patients who are having a
routine Chest CT during treatment for a malignancy and administer Gadolinium contrast and
Iodine contrast during a chest CT exam. The enhancement with the two agents can be compared.
If Gadolinium shows sufficiently good enhancement, the investigators will study the use of
Gadolinium as an alternative to premedication and Iodine in patients who have an iodine
allergy who are suspected of having a pulmonary embolus. This will be registered as a
separate study.
contrast, unless they are premedicated. Premedication can result in a delay in diagnosis,
that can be significant with acute conditions such as Pulmonary embolism.
The investigators are evaluating the use of Gadolinium as an alternative contrast agent in
CT. Gadolinium has been used extensively in MRI exams but the dose that is used is not
sufficient to provide good enhancement on CT. Dual Energy CT is a new technology that has
better sensitivity to lower doses of intravenous contrast and the investigators aim to study
its effectiveness in improving the enhancement with Gadolinium. The investigators will
compare enhancement of Iodine with enhancement of Gadolinium during Dual Energy CT, to
assess the possibility that Gadolinium could be used as an alternative for patients who are
suspected of having Pulmonary embolism. They will recruit up to 50 patients who are having a
routine Chest CT during treatment for a malignancy and administer Gadolinium contrast and
Iodine contrast during a chest CT exam. The enhancement with the two agents can be compared.
If Gadolinium shows sufficiently good enhancement, the investigators will study the use of
Gadolinium as an alternative to premedication and Iodine in patients who have an iodine
allergy who are suspected of having a pulmonary embolus. This will be registered as a
separate study.
Although safe in most patients, iodine may be associated with lifethreatening adverse
events, particularly in high-risk patient. This application is of particular clinical
significance in patients with conditions like pulmonary embolism which could be fatal. CT
pulmonary angiogram (CTPA) with sensitivity of 83-100% and specificity of 89-97% is
currently the gold standard for diagnosis of pulmonary embolism. However, in patients who
have allergy to iodinated contrast agent, CTPA cannot be performed. Gadolinium based
contrast agent can serve as a viable alternative in such patients and can be used for
Gadolinium enhanced MR pulmonary angiography (MRPA) and CTPA. Gadolinium enhanced MRPA
however has inherent limitations in evaluating pulmonary embolism as evident from
multicentre prospective study (PIOPED III) which reported technically inadequate exams in as
many as 25% of patients (range 11% to 52%). The MRPA sensitivity was also low in the range
of 78%. Moreover, unlike CT, low spatial and temporal resolution of MR hampers precise
evaluation of lung parenchyma. Previously investigators have evaluated gadolinium enhanced
CTPA on a single energy CT (SECT) at different tube potential (80 - 120 kV) and reported
encouraging results. However, these patients received higher volume of gadolinium contrast
(mean 53 ml, range 30-64 ml) and in spite, the scans performed at 120 kV demonstrated
overall suboptimal pulmonary artery enhancement. These limitations can be potentially over
come with dual-energy CT which simultaneously acquires low and high energy data. From this
data, monochromatic images can be reconstructed at any desired energy from 40 keV to 140
keV.
This will be a two phase, prospective study. This protocol refers to the first phase of the
study. In the first phase, the investigators aim to recruit up to 50 patients who will guide
in determining gadolinium contrast volume, injection rate and image delay required to
maximize pulmonary arterial enhancement. If the gadolinium enhancement is optimal for
assessment of the pulmonary arteries, the second phase of the study, will use Gadolinium
alone in patients who are allergic to intravenous iodine but are suspected of having a
pulmonary embolus.
events, particularly in high-risk patient. This application is of particular clinical
significance in patients with conditions like pulmonary embolism which could be fatal. CT
pulmonary angiogram (CTPA) with sensitivity of 83-100% and specificity of 89-97% is
currently the gold standard for diagnosis of pulmonary embolism. However, in patients who
have allergy to iodinated contrast agent, CTPA cannot be performed. Gadolinium based
contrast agent can serve as a viable alternative in such patients and can be used for
Gadolinium enhanced MR pulmonary angiography (MRPA) and CTPA. Gadolinium enhanced MRPA
however has inherent limitations in evaluating pulmonary embolism as evident from
multicentre prospective study (PIOPED III) which reported technically inadequate exams in as
many as 25% of patients (range 11% to 52%). The MRPA sensitivity was also low in the range
of 78%. Moreover, unlike CT, low spatial and temporal resolution of MR hampers precise
evaluation of lung parenchyma. Previously investigators have evaluated gadolinium enhanced
CTPA on a single energy CT (SECT) at different tube potential (80 - 120 kV) and reported
encouraging results. However, these patients received higher volume of gadolinium contrast
(mean 53 ml, range 30-64 ml) and in spite, the scans performed at 120 kV demonstrated
overall suboptimal pulmonary artery enhancement. These limitations can be potentially over
come with dual-energy CT which simultaneously acquires low and high energy data. From this
data, monochromatic images can be reconstructed at any desired energy from 40 keV to 140
keV.
This will be a two phase, prospective study. This protocol refers to the first phase of the
study. In the first phase, the investigators aim to recruit up to 50 patients who will guide
in determining gadolinium contrast volume, injection rate and image delay required to
maximize pulmonary arterial enhancement. If the gadolinium enhancement is optimal for
assessment of the pulmonary arteries, the second phase of the study, will use Gadolinium
alone in patients who are allergic to intravenous iodine but are suspected of having a
pulmonary embolus.
Inclusion Criteria:
- patients required to undergo a clinically indicated CT examination
Exclusion Criteria:
- subject less than 20yrs of age
- pregnant women
- Non English speaking
- Abnormal Renal function
- Allergy to Gadolinium
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