Prospective Evaluation of Reduced Dose Computed Tomography for the Detection of Low-Contrast Liver Lesions: Direct Comparison with Concurrent Standard Dose Imaging.
OBJECTIVE
To prospectively compare the diagnostic performance of reduced-dose (RD) contrast-enhanced CT (CECT) with standard-dose (SD) CECT for detection of low-contrast liver lesions.


METHODS
Seventy adults with non-liver primary malignancies underwent abdominal SD-CECT immediately followed by RD-CECT, aggressively targeted at 60-70 % dose reduction. SD series were reconstructed using FBP. RD series were reconstructed with FBP, ASIR, and MBIR (Veo). Three readers-blinded to clinical history and comparison studies-reviewed all series, identifying liver lesions ≥4 mm. Non-blinded review by two experienced abdominal radiologists-assessing SD against available clinical and radiologic information-established the reference standard.


RESULTS
RD-CECT mean effective dose was 2.01 ± 1.36 mSv (median, 1.71), a 64.1 ± 8.8 % reduction. Pooled per-patient performance data were (sensitivity/specificity/PPV/NPV/accuracy) 0.91/0.78/0.60/0.96/0.81 for SD-FBP compared with RD-FBP 0.79/0.75/0.54/0.91/0.76; RD-ASIR 0.84/0.75/0.56/0.93/0.78; and RD-MBIR 0.84/0.68/0.49/0.92/0.72. ROC AUC values were 0.896/0.834/0.858/0.854 for SD-FBP/RD-FBP/RD-ASIR/RD-MBIR, respectively. RD-FBP (P = 0.002) and RD-MBIR (P = 0.032) AUCs were significantly lower than those of SD-FBP; RD-ASIR was not (P = 0.052). Reader confidence was lower for all RD series (P < 0.001) compared with SD-FBP, especially when calling patients entirely negative.


CONCLUSIONS
Aggressive CT dose reduction resulted in inferior diagnostic performance and reader confidence for detection of low-contrast liver lesions compared to SD. Relative to RD-ASIR, RD-FBP showed decreased sensitivity and RD-MBIR showed decreased specificity.


CONCLUSIONS
• Reduced-dose CECT demonstrates inferior diagnostic performance for detecting low-contrast liver lesions. • Reader confidence is lower with reduced-dose CECT compared to standard-dose CECT. • Overly aggressive dose reduction may result in misdiagnosis, regardless of reconstruction algorithm. • Careful consideration of perceived risks versus benefits of dose reduction is crucial.
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
B Dustin
BD
Pooler
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
Meghan G
MG
Lubner
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
David H
DH
Kim
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
Oliver T
OT
Chen
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.|Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
Ke
K
Li
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.|Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA.
Guang-Hong
GH
Chen
Department of Radiology, University of Wisconsin School of Medicine and Public Health, 750 Highland Avenue, Madison, WI, 53705, USA. ppickhardt2@uwhealth.org.|Department of Radiology, University of Wisconsin School of Medicine & Public Health, E3/311 Clinical Science Center, 600 Highland Ave., Madison, WI, 53792-3252, USA. ppickhardt2@uwhealth.org.
Perry J
PJ
Pickhardt
D000328:Adult; D000368:Aged; D000465:Algorithms; D002985:Clinical Protocols; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012372:ROC Curve; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods; D011860:Radiography, Abdominal / Q000379:methods; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
Diagnostic imaging; Liver; Metastases; Multi-detector computed tomography; Radiation dosage