CT follow-up in patients with neuroendocrine tumors (NETs): combined radiation and contrast dose reduction

Abstract

Background Frequent computed tomography (CT) follow-ups involve significant radiation related risks for patients with low-grade neuroendocrine tumors (NETs). Contrast agent (CA) application is essential for diagnostic evidence and has additional risks especially in patients with limited renal function. Purpose To investigate if a combination of dose and contrast agent (CA) reduction affects image quality and diagnostic evidence in neuroendocrine tumor (NET) patients. Material and Methods A total of 51 NET patients were enrolled in the study and 153 CT scans were analyzed. Patients underwent a baseline CT scan (A = 120 kVp, filtered back projection [FBP]) and two follow-up CTs (B = 120 kVp, adaptive statistical iterative reconstruction [ASIR] 40%; C1 = 100 kVp, ASIR 40%; C2 = 100 kVp, ASIR 60%; the latter two protocols were applied with a 30% reduction in CA volume). We evaluated image quality and applied dose. Results In C1/2, the combination of low kV (100 kVp) with ASIR 40%/60% reduced the mean applied dose significantly by 28% compared to B and by 57% compared to A. Signal-to-noise ratio (SNR) and contrast-to-noise ratios (CNR) of tumor to liver/muscle were significantly increased by using C1/2 compared to B and A. With respect to subjective image quality, a slight loss of diagnostic confidence in C1 could be counterbalanced by the higher ASIR blending in C2. Conclusion Combined dose reduction techniques can be used to reduce radiation dose and CA volume without sacrificing image quality and diagnostic confidence in staging CT of NET patients.

Clinical routine use of virtual monochromatic datasets based on spectral CT in patients with hypervascularized abdominal tumors - evaluation of effectiveness and efficiency

“…These findings are confirmed by our objective data, which show higher SNR and CNRs at lower energies. Similar observations have been reported in previous studies (4,13–16). Other studies found that differences in attenuation could be useful for differentiation between HCC and benign liver lesions (14–16).…”

Benefits of Low-Dose CT Scan of Head for Patients With Intracranial Hemorrhage

“…7,8 A previous study demonstrated that radiation dose via multiple CT scans in the same patient could be accumulated compared with a single CT scan. 9 Several studies reported a significant association between exposure to high-dose radiation and increased risk of cortical and posterior subcapsular cataract formation or other lenticular changes. 10,11 A CT scan protocol is typically designed to reliably achieve high-quality images for diagnosing all types of brain diseases.…”

Tailored CT angiography in follow-up after endovascular aneurysm repair (EVAR): combined dose reduction techniques

“…by Boning et al. in oncologic patients (21). This should be investigated in future studies, as it may reduce the risk of contrast-induced kidney injury (27).…”

“…Studies investigating ASIR in abdominal CT have shown that IR algorithms significantly reduce dose while maintaining, or in some cases even improving, image quality (14,20,21).…”

“…Furthermore we did not focus on the possibility of lowering contrast agent volume due to higher iodine attenuation in low-kV protocols as described, e.g. by Boning et al in oncologic patients (21). This should be investigated in future studies, as it may reduce the risk of contrast-induced kidney injury (27).…”