Surgeons’ experience of venous risk with CPA surgery

Neurosurgical Review - The study aims to systematize neurosurgeons’ practical knowledge of venous sacrifice as applied to the posterior fossa region and to analyze the collected data to...     

Intra-rater variability in low-grade glioma segmentation

Assessment of size and growth are key radiological factors in low-grade gliomas (LGGs), both for prognostication and treatment evaluation, but the reliability of LGG-segmentation is scarcely studied. With a diffuse and invasive growth pattern, usually without contrast enhancement, these tumors can be difficult to delineate. The aim of this study was to investigate the intra-observer variability in LGG-segmentation for a radiologist without prior segmentation experience. Pre-operative 3D FLAIR images of 23 LGGs were segmented three times in the software 3D Slicer. Tumor volumes were calculated, together with the absolute and relative difference between the segmentations. To quantify the intra-rater variability, we used the Jaccard coefficient comparing both two (J2) and three (J3) segmentations as well as the Hausdorff Distance (HD). The variability measured with J2 improved significantly between the two last segmentations compared to the two first, going from 0.87 to 0.90 (p?=?0.04). Between the last two segmentations, larger tumors showed a tendency towards smaller relative volume difference (p?=?0.07), while tumors with well-defined borders had significantly less variability measured with both J2 (p?=?0.04) and HD (p?<?0.01). We found no significant relationship between variability and histological sub-types or Apparent Diffusion Coefficients (ADC). We found that the intra-rater variability can be considerable in serial LGG-segmentation, but the variability seems to decrease with experience and higher grade of border conspicuity. Our findings highlight that some criteria defining tumor borders and progression in 3D volumetric segmentation is needed, if moving from 2D to 3D assessment of size and growth of LGGs.

     

Surgical strategy in grade II astrocytoma: a population-based analysis of survival and morbidity with a strategy of early resection as compared to watchful waiting

Background

We recently demonstrated a survival benefit of early resection in unselected diffuse low-grade gliomas (LGG). However, heterogeneity within the LGG entity warrants investigation in a homogenous subgroup. Astrocytoma represents the largest subgroup of LGG, and is characterized by diffuse growth and inferior prognosis. We aimed to study the effects of early resection compared to biopsy and watchful waiting in this subgroup.

Methods

Patient data was retrospectively reviewed in two neurosurgical departments with regional referral practice. In one hospital, initial diagnostic biopsies and watchful waiting was favored, while early resections guided with three-dimensional (3D) ultrasound were advocated in the other hospital. This created a natural experiment with patient management heavy influenced by residential address. In the hospitals’ histopathology databases, all adult patients diagnosed with supratentorial LGG from 1998 through 2009 were screened (n?=?169) and underwent blinded histopathological review. Histopathological review concluded with 117 patients with grade II astrocytomas that were included in the present study. The primary end-point was overall survival assessed by a regional comparison.

Results

Early resections were performed in 51 (82 %) versus 12 (22 %) patients in the respective hospitals (p?<?0.001). The two patient populations were otherwise similar. Median survival was 9.7 years (95 % CI 7.5–11.9) if treated in the hospital favoring early resections compared to 5.6 years (95 % CI 3.5–7.6) if treated at the hospital favoring biopsy and watchful waiting (p?=?0.047). No difference in surgical-related neurological morbidity was seen (p?=?0.843).

Conclusions

Early 3D ultrasound guided resections improve survival, apparently without increased morbidity, compared to biopsy and watchful waiting in patients with diffuse World Health Organization (WHO) grade II astrocytomas.     

Short-term outcome following surgery for rare brain tumor entities in adults: a Swedish nation-wide registry-based study and comparison with SEER database

Journal of Neuro-Oncology - Glioblastoma remains as the most common and aggressive primary adult brain tumor to date. Within the last decade, cancer immunotherapy surfaced as a broadly successful...     

A new system for 3D ultrasound-guided placement of cerebral ventricle catheters

Purpose  

We present a new system for 3D ultrasound-guided placement of cerebral ventricle catheters. The system has been developed with the aim to provide accurate ultrasound-based guidance with only minimal changes to the current surgical technique and workflow.     

Ultrasound imaging in neurosurgery: approaches to minimize surgically induced image artefacts for improved resection control

Background

Intraoperative ultrasound imaging is used in brain tumor surgery to identify tumor remnants. The ultrasound images may in some cases be more difficult to interpret in the later stages of the operation than in the beginning of the operation. The aim of this paper is to explain the causes of surgically induced ultrasound artefacts and how they can be recognized and reduced.

Methods

The theoretical reasons for artefacts are addressed and the impact of surgery is discussed. Different setups for ultrasound acquisition and different acoustic coupling fluids to fill up the resection cavity are evaluated with respect to improved image quality.

Results

The enhancement artefact caused by differences in attenuation of the resection cavity fluid and the surrounding brain is the most dominating surgically induced ultrasound artefact. The influence of the artefact may be reduced by inserting ultrasound probes with small footprint into the resection cavity for a close-up view of the areas with suspected tumor remnants. A novel acoustic coupling fluid developed for use during ultrasound imaging in brain tumor surgery has the potential to reduce surgically induced ultrasound artefacts to a minimum.

Conclusions

Surgeons should be aware of artefacts in ultrasound images that may occur during brain tumor surgery. Techniques to identify and reduce image artefacts are useful and should be known to users of ultrasound in brain tumor surgery.     

Quality of life assessed with EQ-5D in patients undergoing glioma surgery: What is the responsiveness and minimal clinically important difference?

Purpose

To evaluate the responsiveness of EQ-5D 3L in patients undergoing intracranial glioma surgery and estimate the minimal clinically important difference (MCID).

Materials and methods

EQ-5D 3L index values from 164 patients who underwent glioma surgery in the period 2007–2012 were analysed. Responsiveness and MCID were estimated using a combination of distribution-based and anchor-based methods. Karnofsky performance status served as an anchor.

Results

Patients who improved functionally did not report significantly higher EQ-5D 3L scores post operatively with a standardized response mean (SRM) of 0.04 (p = 0.13). Patients who deteriorated functionally reported significantly lower EQ-5D 3L scores post operatively with a SRM of 0.72 (p < 0.001). With different approaches, we determined a range of MCID values from 0.13 to 0.15.

Conclusions

EQ-5D 3L is responsive to changes when glioma patients are deteriorating functionally after surgery but not responsive when the patients are improving. The MCID values for EQ-5D 3L in glioma surgery seem higher than reported MCID values for other types of cancers.