PURPOSE: To assess the feasibility of digital deconvolution techniques
to improve longitudinal resolution of spiral computed tomography (CT)
multiplanar reformations and evaluate how technical factors in deconv
olution affect longitudinal resolution, noise, and edge ringing. MATER
IALS AND METHODS: Longitudinal line spread function (LSF) of the syste
m was estimated from longitudinal reformations of trans-axial spiral C
T images of a step test phantom. By using the estimated LSF, longitudi
nal reformations of the phantom and three clinical spiral CT studies w
ere deconvolved by the methods of Wiener filtering and constrained ite
rative deconvolution. Edge ringing and image noise were quantified for
Wiener filtering and constrained iterative deconvolution. RESULTS: Lo
ngitudinal reformations were substantially deblurred and resolution im
proved after deconvolution. Anatomic boundaries in clinical images wer
e more clearly delineated after restoration. The methods of Wiener dec
onvolution and constrained iterative deconvolution improved the sharpn
ess of the phantom step boundary at the expense of increased edge ring
ing and image noise. CONCLUSION: In longitudinal spiral CT reformation
s, blurring along the longitudinal axis can be reduced by Wiener filte
ring or constrained iterative deconvolution.