Measurement of skeletal muscle area: Comparison of CT and MR imaging.
OBJECTIVE
To investigate the intra- and inter-observer agreement and correlation between CT and MR measurements of skeletal muscle area (SMA) in the abdomen.


METHODS
CT and MR images from twelve patients were analyzed by two blinded observers using segmentation software (MITK-3M3, Mint Medical and Slice-O-Matic, Tomovision) to quantify SMA. MR images included T1w "in-phase", T1w "out-of-phase", and T2w sequences. Inter- and intra-observer agreement was assessed using the intraclass correlation coefficient (ICC). Pearson correlation coefficient (r) was used to correlate measurements obtained on MR with CT. CT and MR measurements were compared with Bland-Altman plots.


RESULTS
Intra- and inter-observer agreement for SMA was high for CT and MR. For MR, the measurements on T2w images showed the highest inter-observer agreement (ICC=0.96). CT SMA correlated closely with MR, with T2w images showing the highest correlation (r=0.98; P<0.01). Bland-Altman plots showed a 1.7%-3.9% bias between CT and MR measurements, lowest for T2w images.


CONCLUSIONS
MR SMA measurements are reproducible and correlate closely with CT. The T2w sequence is recommended to quantify SMA on MR images.
Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States. Electronic address: sinelnikovas@upmc.edu.
Andrey
A
Sinelnikov
Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States.
Chuanxing
C
Qu
Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
David T
DT
Fetzer
Department of Surgery, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
Jean-Sébastien
JS
Pelletier
Department of Medicine, University of Pittsburgh Medical Center, Pittsburgh, PA, United States.
Michael A
MA
Dunn
Department of Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, United States.
Allan
A
Tsung
Department of Radiology, University of Pittsburgh Medical Center, Pittsburgh, PA, United States.
Alessandro
A
Furlan
D005260:Female; D006801:Humans; D008107:Liver Diseases / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000473:pathology*; D015588:Observer Variation; D011237:Predictive Value of Tests; D011379:Prognosis; D011860:Radiography, Abdominal; D015203:Reproducibility of Results; D055948:Sarcopenia / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology*
Image analysis; MR; Sarcopenia; Segmentation; Skeletal muscle area