Table 4:
Summary of findings for technical problems in iMRI suites.
| Study (author and year) | Description Magnetic Field Strength in Tesla (T) | Incidence of outcome | N (included cases) | Data quality GRADING (reason) | Critique/comments |
|---|---|---|---|---|---|
| Archer/McTaggart et al. 2002 | Retrospective case-control study of anesthetic aspects of craniotomy procedures in the iMRI suite compared to the conventional OR. (1.5 T) |
No treatment failures | 152 (76 per cohort) | LOW (observational, matching of cohorts takes only surgical/anatomical factors into account) | Reported “no treatment failures”, defined as “the requirement to limit the anesthetic or operative procedure because of technical problems involving the theatre”. |
| Barua 2009 | Case series that detailed anesthesia considerations for intracranial iMRI procedures, set-up time and surgical results. (0.15 T) |
Unable to perform iMRI scan in 3 cases. | 65 | VERY LOW (observational, no control group) | MRI could not be performed due to body habitus and positioning (n=2) and due to tumor location not amenable to high quality scanning with low field scanner (n=1). |
| Fomekong 2014 | Analysis of pituitary microsurgery using iMRI, primarily focused on surgical considerations. (3 T) |
13 problems: - 11 surgical table blockades, - 1 MRI software bug, - 1 surface coil malposition |
73 | VERY LOW (observational, no control group) | See above. A total of 17 problems were reported, which included anesthesia events. It is unclear if the 17 described problems occurred during 17 separate procedures, or whether one patient experienced >1 problem. |
| Jankovski 2008 | Description of development of the neurosurgical iMRI suite and case series describing the first 21 patients undergoing intracranial surgery in the iMRI suite. This suite includes a special operating room table with an MRI-compatible table top, which moves along tracks into the scan room and then slides onto the MRI table. (3 T) |
16 technical and transfer-related issues, 10 of which prolonged the case for at least 10 minutes. | 21 | VERY LOW (observational, no control group) | Small case series with frank discussion of technical problems encountered: 4 cases with delays due to scan room not yet available (used for non-OR scans), 4 cases with head positioning too high causing minor imaging artifacts, transfer table blockade (n=1), MRI table blockade (n=1), coil unplugged (n=2), coil position artifact (n=1), metal artifact (n=1), MRI software bugs (n=2). The authors described a learning curve without providing actual data for this observation: surgical table blockade occurred “initially frequently” until the problem was identified and fixed. |
| Raheja 2015 | Retrospective analysis of predominantly surgical outcomes of the first consecutive procedures in the iMRI suite. Cases were analyzed and compared in 3 chronologic subgroups (A, B, and C). (1.5 T) |
38 technical problems overall, with decreasing incidence: 31 for group A, 4 for group B, 3 for group C; p<0.001 between A and C Unable to use iMRI in 11 patients due to technical problems. |
300 | LOW (observational, no adjustment for confounders) | Authors report a decreasing rate of technical difficulties over time. Technical difficulty was defined as “complications related to MRI machine, navigation, automatic registration, non-availability of MRI compatible ECG electrodes, operating table malfunction, microscope screen malfunction, planning software, image transfer, air conditioner related and high humidity”. |
Abbreviations: iMRI: intraoperative magnet-resonance imaging; MRI: magnet-resonance imaging; OR: operating room; ECG: electrocardiogram.