[MR-guided biopsies of undetermined liver lesions: technique and results].
OBJECTIVE
To evaluate safety and precision of liver tumor biopsies performed in an open low field system using different sequence techniques.


METHODS
In 47 patients with liver tumors, MR-guided biopsies were performed in a low field system (0.2 Tesla, Magnetom Open, Siemens) using two different sequences. The procedure was monitored with T1-weighted FLASH sequences (TR/TE = 100/9; 70(3)) in all patients and with FISP-Rotated-Keyhole-sequence (TR/TE = 18/8; 90(3)) in additional 20 patients. After positioning of the needle tip in the tumors, 166 biopsy specimens were acquired with 16 G cutting needles (Somatex*). The diameter of the biopsied lesions ranged from 1 to 10 cm (mean diameter 3.2 cm). Visibility of the needles and precision of the biopsies were evaluated.


RESULTS
All interventional biopsies were performed without vascular or organ injuries. Adequate specimens for histologic interpretation were obtained in 42 cases (89.3%). The biopsy results were non-specific in 2 patients (4.2%) and the lesions missed in 3 patients (6.3%). Mean in-room time was 35 minutes and the intervention time was 8.3 minutes. T1-weighted FLASH images proved optimal for confirming needle-tip placement during the biopsies or punctures. Organs, tumors and vessels were easily identified. The FISP sequence proved to be inferior in visualizing vessels and tumors.


CONCLUSIONS
MR-guided liver biopsies are safely and precisely performed using T1-weighted FLASH-sequences with sufficient visualization of the lesions and might be complementary to US- or CT-guided biopsies.
Institut für Diagnostische und Interventionelle Radiologie, Johann-Wolfgang-Goethe-Universität Frankfurt. Zangos@em.uni-frankfurt.de
S
S
Zangos
D
D
Kiefl
K
K
Eichler
K
K
Engelmann
M
M
Heller
C
C
Herzog
M G
MG
Mack
V
V
Jacobi
T J
TJ
Vogl
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle / Q000295:instrumentation*; D003937:Diagnosis, Differential; D004867:Equipment Design; D005260:Female; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000473:pathology* / Q000556:secondary; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity