Early postoperative MRI and detection of residual adenoma after transsphenoidal pituitary surgery

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Current practice guidelines recommend delayed (≥ 3 months after operation) postoperative MRI after transsphenoidal surgery for pituitary adenomas, although this practice defers obtaining important information, such as the presence of a residual adenoma, that might influence patient management during the perioperative period. In this study, the authors compared detection of residual adenomas by means of early postoperative (EPO) MRI (&lt; 48 hours postsurgery) with both surgeon intraoperative assessment and late postoperative (LPO) MRI at 3 months.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Adult patients who underwent microscopic transsphenoidal surgery for pituitary adenomas with MRI preoperatively, &lt; 48 hours after the operation, 3 months postoperatively, and yearly for 4 years were included. The presence or absence of residual tumor was assessed intraoperatively by a single surgeon and postoperatively by 2 neuroradiologists blinded to the intraoperative assessment and other postoperative imaging studies. The presence of residual tumor was confirmed by reresection, tumor growth on imaging, or hormonal evidence. Interreader reliability was calculated at each imaging time point. Specificity, sensitivity, positive predictive value, and negative predictive value for EPO and LPO imaging and intraoperative assessment were determined.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>In total, 102 consecutive patients who underwent microscopic transsphenoidal resection of a pituitary adenoma were included. Eighteen patients (18%) had confirmed residual tumors (12 confirmed by tumor growth, 5 by surgery, and 1 by biochemical evidence of persistent disease). Interreader reliability for detecting residual tumor on EPO MRI was almost perfect (κ = 0.88) and significantly higher than that for LPO MRI (κ = 0.69, p = 0.03). EPO MRI was highly specific for residual tumor (98%), a finding similar to that for intraoperative assessment (99%, p = 0.60) and significantly higher than that for LPO MRI (81%, p &lt; 0.001). Notably, EPO MRI was significantly more sensitive for residual tumor (100%) than both intraoperative assessment (78%, p = 0.04) and LPO MRI (78%, p = 0.04). EPO MRI had a 100% negative predictive value and was used to find 4 residual tumors that were not identified intraoperatively. Residual tumors found on EPO MRI allowed for reresection during the same hospitalization for 3 patients.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>EPO MRI after transsphenoidal pituitary surgery can be reliably interpreted and has greater sensitivity for detecting residual tumor than intraoperative assessment and LPO MRI. This result challenges current guidelines stating that delayed postoperative imaging is preferable to early imaging. Pituitary surgeons should consider performing EPO MRI either in addition to or instead of delayed imaging.</jats:p></jats:sec>

Impact of Intraoperative Magnetic Resonance Imaging (i-MRI) on Surgeon Decision Making and Clinical Outcomes in Cranial Tumor Surgery

“…There is different timing of postoperative MRI (pMRI) for brain tumors in the literature. It is generally common to obtain pMRI within 72 hours 7 12 or even within 24 hours 13 14 to avoid postoperative tissue reactions. However, there are also several publications using late pMRI (3 months) for low-grade glioma 3 15 and pituitary tumors, 16 17 after which postoperative reactions have subsided.…”

Endoscopic endonasal approach for suprasellar meningiomas: introduction of a new scoring system to predict extent of resection and assist in case selection with long-term outcome data

“…50 It is well documented that a surgeon's estimate of EOR is not as accurate as postoperative MRI scans and it is intuitive that the microscope would be able to visualize tumor below the resolution of the naked eye or even loupes. 51 Likewise, after the introduction of stereotactic radiation to the treatment of meningiomas we can infer that a partially resected tumor that responds to radiation may never recur, rendering the EOR irrelevant in this situation and potentially not worth the increased risk that a radical resection might incur. For these reasons, the utility of the Simpson grading at predicting recurrence has been questioned for skull base meningiomas.…”

Magnetic resonance imaging characteristics predict pituitary function in non-functional pituitary macro-adenoma undergoing trans-sphenoidal surgery

“…MRI is universally used in postoperative care pituitary adenomas, for the diagnosis of residual or recurrent tumors [ 11 , 12 ]. This retrospective cohort study conducted among 44 patients who underwent TSS due to non-functional pituitary macroadenoma indicated post-operative TSH and prolactin levels are more likely to be associated with some MRI characteristics before surgery namely size and volume of the tumor.…”

“…Researches evaluated the post-operative MRI characteristics over one year after trans sphenoidal surgery of the non-functional pituitary macroadenomas. The results showed the residual of pituitary adenoma in 18% of patients at 3 months after surgery [ 10 , 11 ]. On the other hand, since the pituitary gland plays an essential role in the control of other endocrine glands, maintaining the function of this gland after surgery is very important and determinating the amount of the normal pituitary tissue after surgery can be very helpful in predicting of the reversibility of pituitary function [ 12 , 13 ].…”