Whole-body MRI for detecting metastatic bone tumor: diagnostic value of diffusion-weighted images.
OBJECTIVE
We assessed the diagnostic value of whole body magnetic resonance (MR) imaging (WB-MRI) using diffusion-weighted images (DWI) for detecting bone metastasis and compared it with that of skeletal scintigraphy (SS).


METHODS
Thirty patients with malignancies (breast cancer, 17 patients; prostate cancer, 9; and one patient each, thyroid cancer, liposarcoma, leiomyosarcoma, and extraskeletal Ewing sarcoma) underwent both WB-MRI and SS to detect bone metastasis. All patients were followed more than 6 months by MR imaging, SS, or computed tomographic (CT) examination. For WB-MRI, patients were placed in feet-first supine position with table-top extender and quadrature body coil. We acquired DWI (axial plane from lower neck to proximal femur) (single shot short TI inversion-recovery [STIR]: repetition time [TR] 6243/echo time [TE] 59/inversion time [TI] 180 ms; b value: 600 s/mm(2); 5-mm slice thickness; 112 x 112 matrix), T(1)-weighted fast spin echo (T(1)WI), and STIR (sagittal plane of total spine images and coronal plane of whole body images) images. Four blinded readers independently and separately interpreted images of combined MR sequences of T(1)WI+STIR (session 1) and T(1)WI+STIR+DWI (session 2).


RESULTS
In 10 of 30 patients, we detected a total of 52 metastatic bone lesions; in the other 20, follow-up examinations confirmed no metastatic bone lesions. For these 52 lesions, for session 2, the mean sensitivity was 96% and the positive predictive value (PPV) was 98%. Those values were superior to those of session 1 (sensitivity: 88%; PPV: 95%) and those of SS (sensitivity: 96%; PPV: 94%).


CONCLUSIONS
WB-MRI that included DWI was useful for detecting bone metastasis.
Nakanishi
Katsuyuki
K
Department of Radiology, Osaka Seamen's Insurance Hospital, Osaka, japan. je2k-nkns@asahi-net.or.jp
Kobayashi
Midori
M
Nakaguchi
Kazunori
K
Kyakuno
Miyaji
M
Hashimoto
Nobuyuki
N
Onishi
Hiromitsu
H
Maeda
Noboru
N
Nakata
Saki
S
Kuwabara
Masatomo
M
Murakami
Takamichi
T
Nakamura
Hironobu
H
D000328:Adult; D000368:Aged; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary*; D001943:Breast Neoplasms / Q000473:pathology; D002277:Carcinoma / Q000556:secondary; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D007890:Leiomyosarcoma / Q000556:secondary; D008080:Liposarcoma / Q000556:secondary; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000473:pathology; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012512:Sarcoma, Ewing / Q000556:secondary; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000473:pathology; D051598:Whole Body Imaging
D019275:Radiopharmaceuticals