Radiographic-clinical correlation in severe acute respiratory syndrome: study of 1373 patients in Hong Kong.
OBJECTIVE
To retrospectively analyze serial chest radiographs in all patients with severe acute respiratory syndrome (SARS) in Hong Kong for temporal changes and differences between patients who died and those who were discharged from the hospital and to compare radiographic and clinical parameters.


METHODS
This retrospective study had ethics review board endorsement, and the need for informed consent was waived. Selected serial chest radiographs obtained from the time of presentation until discharge or death in 1373 patients with laboratory-confirmed SARS were scored. Scoring was based on the area and location of lung opacification on radiographs obtained at each of five milestones (presentation, beginning of ribavirin therapy, beginning of corticosteroid therapy, time of most severe radiographic appearance of disease, and before discharge or death). Extents of lung opacification at these five milestones were compared between patients who died and those who survived (by using a repeated-measures analysis of variance model), and the temporal trend of the radiographic-clinical parameters was analyzed (by using Cochran-Armitage trend testing, Kendall tau correlation coefficients, and descriptive graphic analysis).


RESULTS
The final cohort consisted of 1373 patients (1212 of whom [485 male and 727 female patients; mean age, 38.4 years] survived and 161 of whom [84 male and 77 female patients; mean age, 63.0 years] died). Among survivors, older patients had more extensive radiographic changes than younger ones. However, among patients who died, older patients had less extensive radiographic opacification at the worst stage of disease and just before death than did younger patients. Despite a higher mortality risk for male patients, both sexes in the same outcome group had similar radiographic findings. For both outcome groups, the rate of radiographic progression was similar for the first 11 days but diverged afterwards. The extent of opacification increased by approximately one zone every 4-5 days for the initial 11 days. Radiographic scores correlated with the ratio of PaO2 to the fraction of inspired oxygen, lymphocyte count, lactate dehydrogenase level, and neutrophil count at each milestone and in terms of changes between milestones (P < .01 for all correlation coefficients, except for radiographic score and neutrophil count between the first two milestones).


CONCLUSIONS
The initial extent of radiographic opacification may be useful for prognostic prediction. Radiographic progression correlates well with that of important clinical and laboratory parameters and may be used as an objective prognostic indicator early in SARS.
Antonio
Gregory E
GE
Dept of Diagnostic Radiology and Organ Imaging, Chinese Univ of Hong Kong, Prince of Wales Hosp, Shatin, Hong Kong. gregantonio@cuhk.edu.hk
Ooi
Clara G C
CG
Wong
Ka Tak
KT
Tsui
Eva L H
EL
Wong
Joyce S W
JS
Sy
Alan N L
AN
Hui
Joyce Y H
JY
Chan
Cho Yin
CY
Huang
Henry Y H
HY
Chan
Yip Fai
YF
Wong
Tai Pang
TP
Leong
Lilian L Y
LL
Chan
Jane C K
JC
Ahuja
Anil T
AT
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013902:Radiography, Thoracic; D012189:Retrospective Studies; D045169:Severe Acute Respiratory Syndrome / Q000000981:diagnostic imaging* / Q000401:mortality