Volumetric measurement for comparison of the accuracy between intraoperative CT and postoperative MR imaging in pituitary adenoma surgery

Trouillas's Grading and Post-Surgical Tumor Residue Assessment in Pituitary Adenomas: The Importance of the Multidisciplinary Approach

BACKGROUND

We aim to assess the role of a multidisciplinary approach in pituitary adenomas (PitNETs) classification, evaluate criteria concordance, and compare intraoperative assessments with post-operative MRIs for tumor remnants.

METHODS

Clinical, radiological, histological, and intra- and post-operative data of the treated PitNETs were extracted from prospectively created records. PitNETs were graded according to Trouillas, and the evaluation of the tumor remnants was recorded.

RESULTS

Of 362 PitNETs, 306 underwent surgery, with Trouillas grading assigned to 296. Eight-nine radiologically non-invasive PitNETs progressed to grades 1b (27), 2a (42), or 2b (20) due to proliferative or surgical invasiveness criteria. Twenty-six radiologically invasive tumors were graded 2b due to proliferative criteria. Surgical resection details and post-surgical MRI findings revealed that residual tumors were more common in grades 2a and 2b. During surgery, small tumor remnants were documented in 14 patients which were not visible on post-surgical MRI. Post-surgical MRIs identified remnants in 19 PitNETs not seen during surgery, located in lateral recesses of the sella (4), retrosellar (2), or suprasellar regions (7), along the medial wall of the cavernous sinus (6).

CONCLUSIONS

The Pituitary Board allows for the correct grading of PitNETs to be obtained and an accurate identification of high-risk patients who should undergo closer surveillance due to tumor remnants.

Technical evolution of pediatric neurosurgery: the evolution of intraoperative imaging

Imaging has always been fundamental to neurosurgery, and its evolution over the last century has made a dramatic transformation in the ability of neurosurgeons to define pathology and preserve normal tissue during their operations. In the mid-70 s, the development of computerized cross-sectional imaging with CT scan and subsequently MRI have revolutionized the practice of neurosurgery. Later, further advances in computer technology and medical engineering have allowed the combination of many modalities to bring them into the operating theater. This evolution has allowed real-time intraoperative imaging, in the hope of helping neurosurgeons achieve accuracy, maximal safe resection, and the implementation of minimally invasive techniques in brain and spine pathologies. Augmented reality and robotic technologies are also being applied as useful intra-operative techniques that will improve surgical planning and outcomes in the future. In this article, we will review imaging modalities and provide our institutional perspective on how we have integrated them into our practice.

Comparing MRI volume measurement techniques for pituitary macroadenoma: Investigating volume reduction and its relationship with biochemical control

Pituitary adenomas are one of the most common types of primary intracranial tumors. Measuring pituitary adenoma volume is fundamental for effective management. This study aimed to assess the reliability of the ellipsoid method in comparison with the perimeter method for measuring pituitary macroadenoma volume. In addition, we investigated the correlation between adenoma size reduction and biochemical control in functioning adenomas. This was a retrospective cross-sectional cohort study including 113 patients with pituitary macroadenomas. MRI was obtained for volume measurement by ellipsoid and perimeter methods using two types of DICOM viewer software. Both ellipsoid and perimeter methods exhibit positive, strong, and significant correlations in pituitary macroadenomas in pre-treatment and post-treatment volume (Spearman correlation coefficient 0.95, p-value <0.0001). There was no significant difference in the mean post-treatment pituitary adenoma volume measurements utilizing the ellipsoid and the perimeter methods in different treatment modalities. There were significant differences in the pre-treatment volume measurements between the two methods, both in NFPA and prolactinoma. No correlation was found between volume variability measured by ellipsoid and perimeter methods and the degree of hormonal control in functioning pituitary adenomas. Both the ellipsoid and perimetric methods can be utilized for pituitary adenoma volume measurements as they demonstrate a strong and positive correlation. However, it is important to note that the ellipsoid method tends to result in overestimated tumor volume. There was no correlation between the adenoma size reduction and the degree of biochemical response in functioning adenomas.

Usefulness of Intraoperative Computed Tomography on Extent of Resection of Large and Giant Pituitary Adenomas. Experience from a Developing Country

BACKGROUND AND OBJECTIVE

The literature on the use of intraoperative computed tomography (iCT) is sparse. We provide our experience of the usefulness of iCT in extent of resection in large and giant pituitary adenomas.

METHODS

A retrospective review was performed of cases using the endonasal endoscopic technique in which iCT was used. Demographic factors, number of scans, and impact on the extent of resection are reported, with visual acuity and field changes. Tumors were graded according to the Hardy classification. Patients with cavernous sinus invasion were excluded.

RESULTS

All patients received a perioperative computed tomography scan with our iCT scanner. Thirty patients are reported, including 14 large and 16 giant pituitary adenomas, including 14 nonfunctional and 16 growth hormone-secreting tumors. The overall gross total resection (GTR), near-total resection, and subtotal resection rates were 83.3%, 16.7%, and 3.3%, respectively. iCT scanning detected residual in 13 of 30 patients, including 4 with 14 large (29%) and 9 with 16 (56.3%) giant adenomas promoting further surgery. iCT use improved GTR from 43.8% to 81.3% in giant adenomas and from 71% to 86% in large adenomas. Of the 13 patients in whom iCT detected residual disease, none required >2 iCT scans. No intraoperative complications were observed.

CONCLUSIONS

iCT can improve extent of resection in large and giant pituitary adenomas and facilitate maximum safe resection such as GTR or near-total resection in patients where such should be attempted. iCT use may reduce iatrogenic complications and has select financial benefits in our patients' socioeconomic demographics. However, further prospective controlled studies are required to affirm our conclusions.

Prognostic value of tumor volume for patients with advanced lung cancer treated with chemotherapy

BACKGROUND AND OBJECTIVE

We aim to develop a reference system utilizing computed tomography to calculate changes in tumor volume of lung cancer patients after chemotherapy to assist physicians in clinical treatment and evaluation.

METHODS

Image processing techniques were used to analyze the computed tomography of lung cancer, locate the tumor, and calculate the tumor volume. The medical indicator was then evaluated and analyzed. We examined the correlation between reduced tumor volume and survival duration of 88 patients after chemotherapy at Tri-Service General Hospital, Taiwan. The innovative survival prediction index was obtained by four statistical methods: receiver operating characteristic curve, Youden index, Kaplan-Meier method, and log rank test.

RESULTS

From the image processing techniques, tumor volume from each patient were obtained within an average of 7.25 seconds. The proposed method was shown to achieve rapid positioning of lung tumors and volume reconstruction with an estimation error of 1.92% when calibrated with an irregularly shaped stone. In medical indicator evaluation and analysis, the area below the receiver operating characteristic curve is greater than 0.8, indicating good predictability of the medical index used herein. The Youden index spotted the best cut-off point of volume, and the correlation between the volume's cut-off point and survival time was confirmed again by Kaplan-Meier and log rank test. The p-values were all less than 0.05, presenting a high degree of correlation between the two, indicating that this medical indicator is highly reliable.

CONCLUSIONS

The proposed techniques can automatically find the location of tumors in the lung, reconstruct the volume, and calculate changes in volume before and after treatment, thus obtaining an innovative survival prediction index. This will help facilitate early and accurate predictions of disease outcomes during the course of therapy, and categorize patient stratification into risk groups for more efficient therapies.

Different Volumetric Measurement Methods for Pituitary Adenomas and Their Crucial Clinical Significance

Confirming the status of residual tumors is crucial. In stationary or spontaneous regression cases, early treatments are inappropriate. The long-used geometric calculation formula is 1/2 (length × width × height). However, it yields only rough estimates and is particularly unreliable for irregularly shaped masses. In our study, we attempted to propose a more accurate method. Between 2004 and 2014, 94 patients with pituitary tumors were enrolled in this retrospective study. All patients underwent transsphenoidal surgery and received magnetic resonance imaging (MRI). The pre- and postoperative volumes calculated using the traditional formula were termed A1 and A2, and those calculated using the proposed method were termed O1 and O2, respectively. Wilcoxon signed rank test revealed no significant difference between the A1 and O1 groups (P = 0.1810) but a significant difference between the A2 and O2 groups (P < 0.0001). Significant differences were present in the extent of resection (P < 0.0001), high-grade cavernous sinus invasion (P = 0.0312), and irregular shape (P = 0.0116). Volume is crucial in evaluating tumor status and determining treatment. Therefore, a more scientific method is especially useful when lesions are irregularly shaped or when treatment is determined exclusively based on the tumor volume.

Intraoperative magnetic resonance imaging assessment of non-functioning pituitary adenomas during transsphenoidal surgery

PURPOSE

To review the utility of intraoperative imaging in facilitating maximal resection of non-functioning pituitary adenomas (NFAs).

METHODS

We performed an exhaustive MEDLINE search, which yielded 5598 articles. Upon careful review of these studies, 31 were pertinent to the issue of interest.

RESULTS

Nine studies examined whether intraoperative MRI (iMRI) findings correlated with the presence of residual tumor on MRI taken 3 months after surgical resection. All studies using iMRI of >0.15T showed a ≥90% concordance between iMRI and 3-month post-operative MRI findings. 24 studies (22 iMRI and 2 intraoperative CT) examined whether intraoperative imaging improved the surgeon's ability to achieve a more complete resection. The resections were carried out under microscopic magnification in 17 studies and under endoscopic visualization in 7 studies. All studies support the value of intraoperative imaging in this regard, with improved resection in 15-83% of patients. Two studies examined whether iMRI (≥0.3T) improved visualization of residual NFA when compared to endoscopic visualization. Both studies demonstrated the value of iMRI in this regard, particularly when the tumor is located lateral of the sella, in the cavernous sinus, and in the suprasellar space.

CONCLUSION

The currently available literature supports the utility of intraoperative imaging in facilitating increased NFA resection, without compromising safety.

Prediction of Long-term Post-operative Testosterone Replacement Requirement Based on the Pre-operative Tumor Volume and Testosterone Level in Pituitary Macroadenoma

Non-functioning pituitary macroadenomas (NFPAs) are the most prevalent pituitary macroadenomas. One common symptom of NFPA is hypogonadism, which may require long-term hormone replacement. This study was designed to clarify the association between the pre-operative tumor volume, pre-operative testosterone level, intraoperative resection status and the need of long-term post-operative testosterone replacement. Between 2004 and 2012, 45 male patients with NFPAs were enrolled in this prospective study. All patients underwent transsphenoidal surgery. Hypogonadism was defined as total serum testosterone levels of <2.4 ng/mL. The tumor volume was calculated based on the pre- and post-operative magnetic resonance images. We prescribed testosterone to patients with defined hypogonadism or clinical symptoms of hypogonadism. Hormone replacement for longer than 1 year was considered as long-term therapy. The need for long-term post-operative testosterone replacement was significantly associated with larger pre-operative tumor volume (p = 0.0067), and lower pre-operative testosterone level (p = 0.0101). There was no significant difference between the gross total tumor resection and subtotal resection groups (p = 0.1059). The pre-operative tumor volume and testosterone level impact post-operative hypogonadism. By measuring the tumor volume and the testosterone level and by performing adequate tumor resection, surgeons will be able to predict post-operative hypogonadism and the need for long-term hormone replacement.

Validation study of a fast, accurate, and precise brain tumor volume measurement

Precision and accuracy are sometimes sacrificed to ensure that medical image processing is rapid. To address this, our lab had developed a novel level set segmentation algorithm that is 16× faster and >96% accurate on realistic brain phantoms.

METHODS

This study reports speed, precision and estimated accuracy of our algorithm when measuring MRIs of meningioma brain tumors and compares it to manual tracing and modified MacDonald (MM) ellipsoid criteria. A repeated-measures study allowed us to determine measurement precisions (MPs) - clinically relevant thresholds for statistically significant change.

RESULTS

Speed: the level set, MM, and trace methods required 1:20, 1:35, and 9:35 (mm:ss) respectively on average to complete a volume measurement (p<0.05). Accuracy: the level set was not statistically different to the estimated true lesion volumes (p>0.05). Precision: the MM's within-operator and between-operator MPs were significantly higher (worse) than the other methods (p<0.05). The observed difference in MP between the level set and trace methods did not reach statistical significance (p>0.05).

CONCLUSION

Our level set is faster on average than MM, yet has accuracy and precision comparable to manual tracing.