Impact of 18FFDG-PET/CT and Laparoscopy in Staging of Locally Advanced Gastric Cancer: A Cost Analysis in the Prospective Multicenter PLASTIC-Study.

BACKGROUND: Unnecessary D2-gastrectomy and associated costs can be prevented after detecting non-curable gastric cancer, but impact of staging on treatment costs is unclear. This study determined the cost impact of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18FFDG-PET/CT) and staging laparoscopy (SL) in gastric cancer staging. MATERIALS AND METHODS: In this cost analysis, four staging strategies were modeled in a decision tree: (1) 18FFDG-PET/CT first, then SL, (2) SL only, (3) 18FFDG-PET/CT only, and (4) neither SL nor 18FFDG-PET/CT. Costs were assessed on the basis of the prospective PLASTIC-study, which evaluated adding 18FFDG-PET/CT and SL to staging advanced gastric cancer (cT3-4 and/or cN+) in 18 Dutch hospitals. The Dutch Healthcare Authority provided 18FFDG-PET/CT unit costs. SL unit costs were calculated bottom-up. Gastrectomy-associated costs were collected with hospital claim data until 30 days postoperatively. Uncertainty was assessed in a probabilistic sensitivity analysis (1000 iterations). RESULTS: 18FFDG-PET/CT costs were €1104 including biopsy/cytology. Bottom-up calculations totaled €1537 per SL. D2-gastrectomy costs were €19,308. Total costs per patient were €18,137 for strategy 1, €17,079 for strategy 2, and €19,805 for strategy 3. If all patients undergo gastrectomy, total costs were €18,959 per patient (strategy 4). Performing SL only reduced costs by €1880 per patient. Adding 18FFDG-PET/CT to SL increased costs by €1058 per patient; IQR €870-1253 in the sensitivity analysis. CONCLUSIONS: For advanced gastric cancer, performing SL resulted in substantial cost savings by reducing unnecessary gastrectomies. In contrast, routine 18FFDG-PET/CT increased costs without substantially reducing unnecessary gastrectomies, and is not recommended due to limited impact with major costs. TRIAL REGISTRATION: NCT03208621. This trial was registered prospectively on 30-06-2017.

Radiation dose reduction for CT assessment of urolithiasis using iterative reconstruction: A prospective intra-individual study.

OBJECTIVE: To assess the performance of hybrid (HIR) and model-based iterative reconstruction (MIR) in patients with urolithiasis at reduced-dose computed tomography (CT). METHODS: Twenty patients scheduled for unenhanced abdominal CT for follow-up of urolithiasis were prospectively included. Routine dose acquisition was followed by three low-dose acquisitions at 40%, 60% and 80% reduced doses. All images were reconstructed with filtered back projection (FBP), HIR and MIR. Urolithiasis detection rates, gall bladder, appendix and rectosigmoid evaluation and overall subjective image quality were evaluated by two observers. RESULTS: 74 stones were present in 17 patients. Half the stones were not detected on FBP at the lowest dose level, but this improved with MIR to a sensitivity of 100%. HIR resulted in a slight decrease in sensitivity at the lowest dose to 72%, but outperformed FBP. Evaluation of other structures with HIR at 40% and with MIR at 60% dose reductions was comparable to FBP at routine dose, but 80% dose reduction resulted in non-evaluable images. CONCLUSIONS: CT radiation dose for urolithiasis detection can be safely reduced by 40 (HIR)-60 (MIR) % without affecting assessment of urolithiasis, possible extra-urinary tract pathology or overall image quality. KEY POINTS: • Iterative reconstruction can be used to substantially lower the radiation dose. • This allows for radiation reduction without affecting sensitivity of stone detection. • Possible extra-urinary tract pathology evaluation is feasible at 40-60% reduced dose.

Diagnostic performance of a CT-based scoring system for diagnosis of anastomotic leakage after esophagectomy: comparison with subjective CT assessment.

OBJECTIVE: To develop a CT-based prediction score for anastomotic leakage after esophagectomy and compare it to subjective CT interpretation. METHODS: Consecutive patients who underwent a CT scan for a clinical suspicion of anastomotic leakage after esophagectomy with cervical anastomosis between 2003 and 2014 were analyzed. The CT scans were systematically re-evaluated by two radiologists for the presence of specific CT findings and presence of an anastomotic leak. Also, the original CT interpretations were acquired. These results were compared to patients with and without a clinical confirmed leak. RESULTS: Out of 122 patients that underwent CT for a clinical suspicion of anastomotic leakage; 54 had a confirmed leak. In multivariable analysis, anastomotic leakage was associated with mediastinal fluid (OR = 3.4), esophagogastric wall discontinuity (OR = 4.9), mediastinal air (OR = 6.6), and a fistula (OR = 7.2). Based on these criteria, a prediction score was developed resulting in an area-under-the-curve (AUC) of 0.86, sensitivity of 80%, and specificity of 84%. The original interpretation and the systematic subjective CT assessment by two radiologists resulted in AUCs of 0.68 and 0.75 with sensitivities of 52% and 69%, and specificities of 84% and 82%, respectively. CONCLUSION: This CT-based score may provide improved diagnostic performance for diagnosis of anastomotic leakage after esophagectomy. KEY POINTS: • A CT-based score provides improved diagnostic performance for diagnosis of anastomotic leakage. • Leakage associations include mediastinal fluid, mediastinal air, wall discontinuity, and fistula. • A scoring system yields superior diagnostic accuracy compared to subjective CT assessment. • Radiologists may suggest presence of anastomotic leakage based on a prediction score.