Perspectives Commentary on: Utility of Early Postoperative High-Resolution Volumetric Magnetic Resonance Imaging After Transsphenoidal Pituitary Tumor Surgery by Patel et al. World Neurosurg 82:777-780, 2014
The Early Versus Late Magnetic Resonance Imaging Debate Ivan Ciric and Hamad Farhat
I
t is a generally accepted adage that a follow-up magnetic resonance imaging (MRI) in the wake of transsphenoidal surgery for a pituitary macroadenoma is best obtained between 4 and 8 weeks after surgery. The rationale behind this thinking is that an early MRI may be unreliable at best and confusing at worst in revealing the accurate finite result of the extent of tumor removal, relative to the position of the residual pituitary gland and as to the postoperative anatomy of the surgical corridor. Nevertheless, perspicacious neurosurgeons, with their well-honed instincts, readily obtain an early posttranssphenoidal surgery MRI when the clinical situation so demands. The most notable example in this regard would be the absence of any visual improvement or, even worse, the presence of an immediate postoperative visual deterioration. These truisms were not invalidated but rather augmented by the introduction of the intraoperative MRI that ostensibly can identify all of the accessible pituitary tumor tissue and thus facilitate its removal, avoiding thereby the unsavory discovery of a substantial residual tumor on the late MRI and obviate the challenges of a late reoperation.
In a recent issue of WORLD NEUROSURGERY, in their cogently structured recent publication “Utility of Early Post-operative High Resolution Volumetric MR Imaging after Transsphenoidal Pituitary Surgery,” Patel et al. from the Cornell Medical College offer a variant on the conventional wisdom relative to an early versus late posttranssphenoidal surgery MRI and an alternative to the intraoperative MRI. They base their well-researched paradigm on the high-resolution volumetric MRI of the residual tumor, of the postoperative tumor bed cavity, and considering the relationship of the accrued imaging findings to the visual outcome.
Key words Pituitary adenoma - Transsphenoidal - Volumetric MRI -
Abbreviations and Acronyms MRI: Magnetic resonance imaging
The conclusions reached are perhaps somewhat incongruous. For example, although the study has found no statistical difference in the volume of the residual tumor on the early (1.18 cm3) versus the late (1.23 cm3) MRI, it also revealed that the early MRI has a tendency to underestimate the amount of the residual tumor in 27% of the 40 cases studied and to overestimate it in 10% of cases. Indeed, the authors readily concede that the main advantage of an early MRI is not in quantifying the amount of the residual tumor tissue but rather in its ability to detect such tissue. Thus, they recommend obtaining an early MRI as an alternative to the more expensive intraoperative MRI as a model for assessing the need for an early reoperation. The authors also offer sound advice as to the indications for an early reoperation. Specifically, they recommend early reoperation in patients with postoperative visual worsening when there is no evidence of a reduction in the tumor bed cavity size. Conversely, and perhaps intuitively less appealing, the authors favor an abstemious attitude in terms of placing a surgical indication for an early reoperation when there is evidence on the MRI of a decrease in the tumor bed cavity size. They base this conservative attitude on their experience that when there is evidence for postoperative tumor bed shrinkage, the vision tends to improve spontaneously. As is usually the case in such debates, the ultimate purveyor of truth is the neurosurgeons’ common sense and the specificity of each individual case. Certainly, there is no authority that would find fault with, let alone censure, a neurosurgeon for obtaining an early MRI when the patient wakes up after transsphenoidal surgery
From the Evanston Hospital, Neurosurgery, Evanston, Illinois, USA; and Department of Neurosurgery, NorthShore University HealthSystem, Evanston, Illinois, USA To whom correspondence should be addressed: Ivan Ciric, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015) 83, 4:471-472. http://dx.doi.org/10.1016/j.wneu.2014.08.048
WORLD NEUROSURGERY 83 [4]: 471-472, APRIL 2015
www.WORLDNEUROSURGERY.org
471
PERSPECTIVES
only to complain of worsened vision, be it secondary to a suspected hemorrhage or simply attributable to the sheer mass of residual tumor perhaps admixed with a hematoma. It would appear to us that, short of an intraoperative MRI, the central issue in this debate is the potential need to determine the presence of residual tumor that may have escaped intraoperative discovery and that may constitute an indication for an early reoperation.
than meaningful for whatever reason providing, of course, that the neurosurgeon has the wherewithal of a genuine rather than contrived confidence, superimposed on a realistic self assessment of abilities and experience, of being reasonably sure that he or she could perform a better job the second time around.
In majority of cases, pituitary neurosurgeons have a fairly reliable grasp as to whether a meaningful resection was accomplished. We suppose this perception grows with experience. And so, in addition to the obvious indication of a postoperative visual deterioration, an early posttranssphenoidal surgery MRI might be a good idea when in surgeon’s estimation the resection was less
Citation: World Neurosurg. (2015) 83, 4:471-472. http://dx.doi.org/10.1016/j.wneu.2014.08.048 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
Call for Neurosurgery and the Arts World Neurosurgery is changing the cover art and filler art motif. This motif involves the display of art by neurosurgeons. Hence, we are seeking art, in any visual form, for this endeavor on an ongoing basis. Such art might naturally include photography, photographs of sculptures or paintings, prose or poetry, etc. We ask Neurosurgeons to submit high resolution images of such art. These images will be considered for future World Neurosurgery journal covers and for filler art. When submitting your images, please include a brief description. These can be submitted directly to [email protected].
472
www.SCIENCEDIRECT.com
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2014.08.048
The Early Versus Late Magnetic Resonance Imaging Debate Ivan Ciric and Hamad Farhat
I
t is a generally accepted adage that a follow-up magnetic resonance imaging (MRI) in the wake of transsphenoidal surgery for a pituitary macroadenoma is best obtained between 4 and 8 weeks after surgery. The rationale behind this thinking is that an early MRI may be unreliable at best and confusing at worst in revealing the accurate finite result of the extent of tumor removal, relative to the position of the residual pituitary gland and as to the postoperative anatomy of the surgical corridor. Nevertheless, perspicacious neurosurgeons, with their well-honed instincts, readily obtain an early posttranssphenoidal surgery MRI when the clinical situation so demands. The most notable example in this regard would be the absence of any visual improvement or, even worse, the presence of an immediate postoperative visual deterioration. These truisms were not invalidated but rather augmented by the introduction of the intraoperative MRI that ostensibly can identify all of the accessible pituitary tumor tissue and thus facilitate its removal, avoiding thereby the unsavory discovery of a substantial residual tumor on the late MRI and obviate the challenges of a late reoperation.
In a recent issue of WORLD NEUROSURGERY, in their cogently structured recent publication “Utility of Early Post-operative High Resolution Volumetric MR Imaging after Transsphenoidal Pituitary Surgery,” Patel et al. from the Cornell Medical College offer a variant on the conventional wisdom relative to an early versus late posttranssphenoidal surgery MRI and an alternative to the intraoperative MRI. They base their well-researched paradigm on the high-resolution volumetric MRI of the residual tumor, of the postoperative tumor bed cavity, and considering the relationship of the accrued imaging findings to the visual outcome.
Key words Pituitary adenoma - Transsphenoidal - Volumetric MRI -
Abbreviations and Acronyms MRI: Magnetic resonance imaging
The conclusions reached are perhaps somewhat incongruous. For example, although the study has found no statistical difference in the volume of the residual tumor on the early (1.18 cm3) versus the late (1.23 cm3) MRI, it also revealed that the early MRI has a tendency to underestimate the amount of the residual tumor in 27% of the 40 cases studied and to overestimate it in 10% of cases. Indeed, the authors readily concede that the main advantage of an early MRI is not in quantifying the amount of the residual tumor tissue but rather in its ability to detect such tissue. Thus, they recommend obtaining an early MRI as an alternative to the more expensive intraoperative MRI as a model for assessing the need for an early reoperation. The authors also offer sound advice as to the indications for an early reoperation. Specifically, they recommend early reoperation in patients with postoperative visual worsening when there is no evidence of a reduction in the tumor bed cavity size. Conversely, and perhaps intuitively less appealing, the authors favor an abstemious attitude in terms of placing a surgical indication for an early reoperation when there is evidence on the MRI of a decrease in the tumor bed cavity size. They base this conservative attitude on their experience that when there is evidence for postoperative tumor bed shrinkage, the vision tends to improve spontaneously. As is usually the case in such debates, the ultimate purveyor of truth is the neurosurgeons’ common sense and the specificity of each individual case. Certainly, there is no authority that would find fault with, let alone censure, a neurosurgeon for obtaining an early MRI when the patient wakes up after transsphenoidal surgery
From the Evanston Hospital, Neurosurgery, Evanston, Illinois, USA; and Department of Neurosurgery, NorthShore University HealthSystem, Evanston, Illinois, USA To whom correspondence should be addressed: Ivan Ciric, M.D. [E-mail: [email protected]] Citation: World Neurosurg. (2015) 83, 4:471-472. http://dx.doi.org/10.1016/j.wneu.2014.08.048
WORLD NEUROSURGERY 83 [4]: 471-472, APRIL 2015
www.WORLDNEUROSURGERY.org
471
PERSPECTIVES
only to complain of worsened vision, be it secondary to a suspected hemorrhage or simply attributable to the sheer mass of residual tumor perhaps admixed with a hematoma. It would appear to us that, short of an intraoperative MRI, the central issue in this debate is the potential need to determine the presence of residual tumor that may have escaped intraoperative discovery and that may constitute an indication for an early reoperation.
than meaningful for whatever reason providing, of course, that the neurosurgeon has the wherewithal of a genuine rather than contrived confidence, superimposed on a realistic self assessment of abilities and experience, of being reasonably sure that he or she could perform a better job the second time around.
In majority of cases, pituitary neurosurgeons have a fairly reliable grasp as to whether a meaningful resection was accomplished. We suppose this perception grows with experience. And so, in addition to the obvious indication of a postoperative visual deterioration, an early posttranssphenoidal surgery MRI might be a good idea when in surgeon’s estimation the resection was less
Citation: World Neurosurg. (2015) 83, 4:471-472. http://dx.doi.org/10.1016/j.wneu.2014.08.048 Journal homepage: www.WORLDNEUROSURGERY.org Available online: www.sciencedirect.com 1878-8750/$ - see front matter ª 2015 Elsevier Inc. All rights reserved.
Call for Neurosurgery and the Arts World Neurosurgery is changing the cover art and filler art motif. This motif involves the display of art by neurosurgeons. Hence, we are seeking art, in any visual form, for this endeavor on an ongoing basis. Such art might naturally include photography, photographs of sculptures or paintings, prose or poetry, etc. We ask Neurosurgeons to submit high resolution images of such art. These images will be considered for future World Neurosurgery journal covers and for filler art. When submitting your images, please include a brief description. These can be submitted directly to [email protected].
472
www.SCIENCEDIRECT.com
WORLD NEUROSURGERY, http://dx.doi.org/10.1016/j.wneu.2014.08.048
