Results of a prospective multicenter study for evaluation of the diagnostic quality of an open whole-body low-field MRI unit. A comparison with high-field MRI measured by the applicable gold standard.
OBJECTIVE
To evaluate the diagnostic quality of an open whole-body low-field MRI scanner compared to high-field scanners.


METHODS
Over a period of 3 months, 401 patients with diseases of the kidney (n = 78), the shoulder (n = 122), the spine (n = 105) and the cerebrum (n = 96) were prospectively evaluated in four participating centers. They all underwent clinical evaluation, low-field and high-field MRI examination and surgical or follow-up confirmation of diagnosis. Clinical, histopathologic, high-field and low-field MRI diagnoses were recorded in standardized questionnaires that were centrally evaluated. Statistical evaluation comprised two parts: ROC analysis assessed accuracy of MRI and clinical diagnoses; furthermore rates of concordance of high- and low-field MRI diagnosis were calculated.


RESULTS
We found no statistically relevant difference in high-field MRI diagnosis compared to low-field MRI diagnostic accuracy measured by clinical or surgical gold standard in three of the four regions examined; in cerebral examinations there was a small yet significant advantage for the high-field systems (P = 0.01).


CONCLUSIONS
We conclude that the open low-field scanner we evaluated using clinical and surgical gold standard as reference is able to achieve comparable diagnostic accuracy compared to high-field scanners at lower costs and greater patient comfort. Limitations due to field strength (signal-to-noise ratio, resolution, scan time) seem to be relevant only in a very small number of cases that warrant high-field examination.
Merl
T
T
Institute of Diagnostic Radiology, Klinikum rechts der Isar, Technischen Universität München, Germany. thomas.merl@lrz.tum.de
Scholz
M
M
Gerhardt
P
P
Langer
M
M
Laubenberger
J
J
Weiss
H D
HD
Gehl
H B
HB
Wolf
K J
KJ
Ohnesorge
I
I
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001927:Brain Diseases / Q000175:diagnosis; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D007592:Joint Diseases / Q000175:diagnosis; D007680:Kidney Neoplasms / Q000175:diagnosis; D008279:Magnetic Resonance Imaging / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012372:ROC Curve; D012782:Shoulder; D013122:Spinal Diseases / Q000175:diagnosis