Feasibility Study of Using Gemstone Spectral Imaging (GSI) and Adaptive Statistical Iterative Reconstruction (ASIR) for Reducing Radiation and Iodine Contrast Dose in Abdominal CT Patients with High BMI Values

<div><p>Purpose</p><p>To prospectively investigate the effect of using Gemstone Spectral Imaging (GSI) and adaptive statistical iterative reconstruction (ASIR) for reducing radiation and iodine contrast dose in abdominal CT patients with high BMI values.</p><p>Materials and Methods</p><p>26 patients (weight > 65kg and BMI ≥ 22) underwent abdominal CT using GSI mode with 300mgI/kg contrast material as study group (group A). Another 21 patients (weight ≤ 65kg and BMI ≥ 22) were scanned with a conventional 120 kVp tube voltage for noise index (NI) of 11 with 450mgI/kg contrast material as control group (group B). GSI images were reconstructed at 60keV with 50%ASIR and the conventional 120kVp images were reconstructed with FBP reconstruction. The CT values, standard deviation (SD), signal-noise-ratio (SNR), contrast-noise-ratio (CNR) of 26 landmarks were quantitatively measured and image quality qualitatively assessed using statistical analysis.</p><p>Results</p><p>As for the quantitative analysis, the difference of CNR between groups A and B was all significant except for the mesenteric vein. The SNR in group A was higher than B except the mesenteric artery and splenic artery. As for the qualitative analysis, all images had diagnostic quality and the agreement for image quality assessment between the reviewers was substantial (kappa = 0.684). CT dose index (CTDI) values for non-enhanced, arterial phase and portal phase in group A were decreased by 49.04%, 40.51% and 40.54% compared with group B (P = 0.000), respectively. The total dose and the injection rate for the contrast material were reduced by 14.40% and 14.95% in A compared with B.</p><p>Conclusion</p><p>The use of GSI and ASIR provides similar enhancement in vessels and image quality with reduced radiation dose and contrast dose, compared with the use of conventional scan protocol.</p></div

The measurement in ROI of AA1, CA, PV, SV, L-A, S-A, P-A, M-A, L-P, P-P, S-P and M-P in protocol B.

<p>The measurement in ROI of AA1, CA, PV, SV, L-A, S-A, P-A, M-A, L-P, P-P, S-P and M-P in protocol B.</p

The scan parameter and contrast agent in protocol A and B.

<p>The scan parameter and contrast agent in protocol A and B.</p

The measurement in ROI of AA1, AA2, SA, RCIA, MA, RPV, PV, SV, P-A, L-P, P-P and S-P in protocol A.

<p>The measurement in ROI of AA1, AA2, SA, RCIA, MA, RPV, PV, SV, P-A, L-P, P-P and S-P in protocol A.</p

GIST overlooked in CT images.

<p>A 64-year-old male with duodenal GISTs presented with melena for the past 20 days. A. Enhanced CT image demonstrates bowel wall thickening at the third segment on the axial section of the CT image and was overlooked. B. Post-procedural CT images (sagittal section) reveal the lesion more clearly. One radiologist had overlooked the lesion, while the other radiologist had misdiagnosed it as a heterotopic pancreas.</p

Clinicopathologic characteristics of small bowel GISTs in 197 patients.

<p>Clinicopathologic characteristics of small bowel GISTs in 197 patients.</p

CT findings of small bowel GISTs in 197 patients.

<p>CT findings of small bowel GISTs in 197 patients.</p

Jejunum GISTs with liver metastasis.

<p>A 64-year-old female with jejunum GISTs with liver metastasis presented with clinical abdominal pain for 6 months, and ultrasound examination detected liver masses for 1 week. A. Enhanced CT image reveals a lobular mass with severe necrosis and periphery enhancement. B. The axial section of the liver shows low-density lesions in the liver with slight enhancement. The patient was diagnosed with a malignant stromal tumor and hepatic metastasis. C. After treatment with Gleevec, the neoplasm became cystic and reduced in size.</p