Lancet: Intraoperative MRI helps optimizes brain tumor resection
Intraoperative MRI provides a method to improve the extent of resection of malignant brain tumors compared with the conventional microsurgical approach, according to a study published in the October issue of Lancet Oncology.
Neurosurgeons have increasingly turned to intraoperative MRI. Previous reports have suggested its utility in detecting residual tumor tissue and touted a survival benefit when extent of resection was employed as prognostic factor. “However, the level of scientific evidence for use of intraoperative MRI guidance is low,” wrote Christian Senft, MD, of the department of neurosurgery at Goethe University in Frankfurt, Germany, and colleagues.
Senft et al designed the current study to determine whether intraoperative MRI guidance leads to a higher rate of complete tumor resection than conventional resection. The study team enrolled 58 patients between Oct. 1, 2007, and July 1, 2010. Among those eligible for analysis, 24 were assigned to the intraoperative MRI group and 25 to the control group.
The primary endpoint of the study was extent of resection. Patients were imaged seven days before surgery and 72 hours after surgery. A neuroradiologist blinded to patient group interpreted each exam to determine the extent of resection.
Ninety-six percent of the intraoperative patients achieved complete resections compared with 68 percent in the control group. Among patients in the intraoperative MRI group, 33 percent underwent extended tumor resection based on imaging data.
Furthermore, at six months post-surgery 67 percent of patients in the intraoperative group remained stable compared with 36 percent in the control group.
Senft and colleagues noted that intraoperative MRI procedures were longer than control procedures, with mean surgical procedure times of 250 minutes and 227 minutes, respectively. Furthermore, overall time in the operating room was longer in the intraoperative group (mean time, 429 minutes) than in the control group (mean time, 362 minutes), reported Senft et al.
The researchers emphasized that previous studies have established the need to improve intraoperative visualization of tumor tissue, and referred to “strikingly high rates of incorrect assumptions made by surgeons about the extent of resections.”
Senft and colleagues noted that brain-shift occurs during neurosurgical procedures, making preoperative images and conventional neuronavigation somewhat inaccurate during the procedure, which explains why surgeons may overlook tumor remnants.
The authors noted that enhanced resection did not increase surgical morbidity. In addition, the complication rate in the intraoperative MRI group mirrored that of conventional procedures.
Senft et al acknowledged shortcomings to the study, pointing out that a double-blind design is impossible for this type of study. The institution also upgraded from 1.5T MRI to 3T MRI during the course of the study. Finally, the researchers did not assess quality of life.
The authors called for additional research in two areas: the impact of intraoperative MRI on survival and measurements of quality of life. They also wrote, “Whether resection control is best implemented by use of an intraoperative MRI device, or by visualization of 5-aminolaevulinic acid remains to be seen.” Future studies, they said, should employ either intraoperative MRI or 5-aminolaevulinic acid as a control.
Neurosurgeons have increasingly turned to intraoperative MRI. Previous reports have suggested its utility in detecting residual tumor tissue and touted a survival benefit when extent of resection was employed as prognostic factor. “However, the level of scientific evidence for use of intraoperative MRI guidance is low,” wrote Christian Senft, MD, of the department of neurosurgery at Goethe University in Frankfurt, Germany, and colleagues.
Senft et al designed the current study to determine whether intraoperative MRI guidance leads to a higher rate of complete tumor resection than conventional resection. The study team enrolled 58 patients between Oct. 1, 2007, and July 1, 2010. Among those eligible for analysis, 24 were assigned to the intraoperative MRI group and 25 to the control group.
The primary endpoint of the study was extent of resection. Patients were imaged seven days before surgery and 72 hours after surgery. A neuroradiologist blinded to patient group interpreted each exam to determine the extent of resection.
Ninety-six percent of the intraoperative patients achieved complete resections compared with 68 percent in the control group. Among patients in the intraoperative MRI group, 33 percent underwent extended tumor resection based on imaging data.
Furthermore, at six months post-surgery 67 percent of patients in the intraoperative group remained stable compared with 36 percent in the control group.
Senft and colleagues noted that intraoperative MRI procedures were longer than control procedures, with mean surgical procedure times of 250 minutes and 227 minutes, respectively. Furthermore, overall time in the operating room was longer in the intraoperative group (mean time, 429 minutes) than in the control group (mean time, 362 minutes), reported Senft et al.
The researchers emphasized that previous studies have established the need to improve intraoperative visualization of tumor tissue, and referred to “strikingly high rates of incorrect assumptions made by surgeons about the extent of resections.”
Senft and colleagues noted that brain-shift occurs during neurosurgical procedures, making preoperative images and conventional neuronavigation somewhat inaccurate during the procedure, which explains why surgeons may overlook tumor remnants.
The authors noted that enhanced resection did not increase surgical morbidity. In addition, the complication rate in the intraoperative MRI group mirrored that of conventional procedures.
Senft et al acknowledged shortcomings to the study, pointing out that a double-blind design is impossible for this type of study. The institution also upgraded from 1.5T MRI to 3T MRI during the course of the study. Finally, the researchers did not assess quality of life.
The authors called for additional research in two areas: the impact of intraoperative MRI on survival and measurements of quality of life. They also wrote, “Whether resection control is best implemented by use of an intraoperative MRI device, or by visualization of 5-aminolaevulinic acid remains to be seen.” Future studies, they said, should employ either intraoperative MRI or 5-aminolaevulinic acid as a control.