Case Series of Applications of Resting State Functional MRI in Brain Tumor Surgery: A Novel Technique

Background The extent of resection for brain tumors is a critical factor in determining the oncologic outcome for a patient. However, a balance between preservation of neurological function and maximal resection is essential for true benefit.Functional magnetic resonance imaging (fMRI) is one of the approaches that augments the neurosurgeon's ability to attain maximal safe resection by providing preoperative mapping. It may not be possible to perform awake craniotomy with intraoperative localization by direct cortical stimulation in all patients, such as children and those with neurocognitive impairment. Task-based fMRI may have limited value in these cases due to low patient cooperability. Methods In this article we present in a case-based format, the various clinical scenarios where resting state fMRI (rs-fMRI) can be helpful in guiding neurosurgical resection. rs-fMRI of the patients has been acquired on Philips 1.5 T system. Seed voxel method has been used for processing and analysis. Conclusion rs-fMRI does not require active patient cooperation to generate useful information and thus can be a promising tool in patients unable to cooperate for task-based studies.

Mapping of Language-and-Memory Networks in Patients With Temporal Lobe Epilepsy by Using the GE2REC Protocol

Preoperative mapping of language and declarative memory functions in temporal lobe epilepsy (TLE) patients is essential since they frequently encounter deterioration of these functions and show variable degrees of cerebral reorganization. Due to growing evidence on language and declarative memory interdependence at a neural and neuropsychological level, we propose the GE2REC protocol for interactive language-and-memory network (LMN) mapping. GE2REC consists of three inter-related tasks, sentence generation with implicit encoding (GE) and two recollection (2REC) memory tasks: recognition and recall. This protocol has previously been validated in healthy participants, and in this study, we showed that it also maps the LMN in the left TLE (N = 18). Compared to healthy controls (N = 19), left TLE (LTLE) showed widespread inter- and intra-hemispheric reorganization of the LMN through reduced activity of regions engaged in the integration and the coordination of this meta-network. We also illustrated how this protocol could be implemented in clinical practice individually by presenting two case studies of LTLE patients who underwent efficient surgery and became seizure-free but showed different cognitive outcomes. This protocol can be advantageous for clinical practice because it (a) is short and easy to perform; (b) allows brain mapping of essential cognitive functions, even at an individual level; (c) engages language-and-memory interaction allowing to evaluate the integrative processes within the LMN; (d) provides a more comprehensive assessment by including both verbal and visual modalities, as well as various language and memory processes. Based on the available postsurgical data, we presented preliminary results obtained with this protocol in LTLE patients that could potentially inform the clinical practice. This implies the necessity to further validate the potential of GE2REC for neurosurgical planning, along with two directions, guiding resection and describing LMN neuroplasticity at an individual level.

Non-invasive mapping of cortical categorization function by repetitive navigated transcranial magnetic stimulation

Over the past years navigated repetitive transcranial magnetic stimulation (nrTMS) had become increasingly important for the preoperative examination and mapping of eloquent brain areas. Among other applications it was demonstrated that the detection of neuropsychological function, such as arithmetic processing or face recognition, is feasible with nrTMS. In order to investigate the mapping of further brain functions, this study aims to investigate the cortical mapping of categorization function via nrTMS. 20 healthy volunteers purely right-handed, with German as mother tongue underwent nrTMS mapping using 5 Hz/10 pulses. 52 cortical spots spread over each hemisphere were stimulated. The task consisted of 80 pictures of living and non-living images, which the volunteers were instructed to categorize while the simulation pulses were applied. The highest error rates for all errors of all subjects were observed in the left hemisphere’s posterior middle frontal gyrus (pMFG) with an error rate of 60%, as well as in the right pMFG and posterior supra marginal gyrus (pSMG) (45%). In total the task processing of non-living objects elicited more errors in total, than the recognition of living objects. nrTMS is able to detect cortical categorization function. Moreover, the observed bihemispheric representation, as well as the higher error incidence for the recognition of non-living objects is well in accordance with current literature. Clinical applicability for preoperative mapping in brain tumor patients but also in general neuroscience has to be evaluated as the next step.

Long-term Use of Ultrasound for Locating Optimal LVA Sites: A Descriptive Data Analysis

Background Preoperative mapping of lymphatic vessels for lymphovenous anastomosis (LVA) surgery is frequently performed by indocyanine green (ICG) lymphography solely; however, other imaging modalities, such as ultrasound (US), might be more efficient, particularly for Caucasian patients. We present our preoperative assessment protocol, experience, and approach of using US for locating optimal LVA sites. Material and Methods Fifty-six (16 males) lymphedema patients who underwent LVA surgery were included in this study, 5 of whom received two LVA operations. In total, 61 LVA procedures with 233 dissected lymphatic vessels were evaluated. Preoperative US was performed by the author S.M. 2 days before intraoperative ICG lymphography. Fluid-predominant lymphedema regions were scanned more profoundly. Skin incisions followed preoperative US and ICG lymphography markings. Detection of lymphatic vessels was compared between ICG lymphography and the US by using the intraoperative verification under the microscope with 20 to 50x magnification as the reference standard. Results Among the dissected lymphatic vessels, 83.3% could be localized by US, and 70% were detectable exclusively by it. In all, 7.2% of US-detected lymphatic vessels could not be found and verified intraoperatively. Among the lymphatic vessels found by US, only 16% were apparent with ICG before skin incision. In total, 23.2% of the dissected lymphatic vessels could be visualized with ICG lymphography preoperatively. Only 9.9% of the lymphatic vessels could be found by ICG alone. Conclusion High-frequency US mapping accurately finds functional lymphatic vessels and matching veins. It locates fluid-predominant regions for targeted LVA surgeries. It reveals 3.6 times as many lymphatic vessels as ICG lymphography. In our practice, it has an integral role in planning LVA procedures.

Presurgical language mapping in bilingual children using transcranial magnetic stimulation: illustrative case

BACKGROUND Presurgical mapping of eloquent cortex in young patients undergoing neurosurgery is critical but presents challenges unique to the pediatric population, including motion artifact, noncompliance, and sedation requirements. Furthermore, as bilingualism in children increases, functional mapping of more than one language is becoming increasingly critical. Transcranial magnetic stimulation (TMS), a noninvasive brain stimulation technique, is well suited to evaluate language areas in children since it does not require the patient to remain still during mapping. OBSERVATIONS A 13-year-old bilingual male with glioblastoma multiforme involving the left parietal lobe and deep occipital white matter underwent preoperative language mapping using magnetic resonance imaging-guided TMS. Language-specific cortices were successfully identified in both hemispheres. TMS findings aided in discussing with the family the risks of postsurgical deficits of tumor resection; postoperatively, the patient had intact bilingual speech and was referred for chemotherapy and radiation. LESSONS The authors’ findings add to the evolving case for preoperative dual language mapping in bilingual neurosurgical candidates. The authors illustrate the feasibility and utility of TMS as a noninvasive functional mapping tool in this child. TMS is safe, effective, and can be used for preoperative mapping of language cortex in bilingual children to aid in surgical planning and discussion with families.

Upper limb anatomy and preoperative mapping

Vascular access is absolutely essential for haemodialysis due to its relationship with quality of dialysis and associated morbidity. Therefore, it must be monitored and continuously surveilled from the moment it is created to prevent failure in maturation and thrombosis. Multidisciplinary collaboration is necessary when the main aim is to achieve the adequate vascular access flow with the fewest possible complications. The starting point, and probably the main one, is vascular access planning. This planning requires both a deep understanding of the anatomy of the upper limb and enough skill to examine it by Doppler ultrasound. The aim of this article is to review the anatomical and haemodynamical concepts of the arterial and venous vascular tree and explain how to perform ultrasound mapping, optimising the technical resources provided by this tool. Likewise, adequate access creation criteria that minimise the risk of failure and associated complications will be discussed.

Postmastectomic lymphedema prevention: modern possibilities

A three-dimensional computer model of the topographic and anatomical variants of the lymph nodes in the axillary fossa gives reason to doubt the indisputability of the known data on the normal anatomy of the lymph nodes. This mainly concerns the presence of a lateral (shoulder) group of axillary lymph nodes (4-6 nodes), which can be located not only on the medial, but also on the posterior surface of the shoulder. In some cases, this group of axillary lymph nodes is generally absent in its typical place and is in close proximity to the central (intermediate) group of lymph nodes. Attention to the lateral (shoulder) group of lymph nodes is due to the fact that through them lymph drainage occurs from the entire superficial (epifascial) lymphatic system of the volar surface of the upper limb (skin and subcutaneous tissue). From the lateral group of lymph nodes, lymph drainage goes either to the central group or to the deltapectoral lymph nodes. In the course of axillary lymph node dissection of I, II and III levels in breast cancer, it is possible to save only the deltapectal lymph node with its afferent and efferent vessels, which provides full-fledged lymphatic drainage from the dorsolateral surface of the upper limb. But in this situation, without lymphatic drainage (superficial and deep) with preserved lymph production, the inner (volar) part of the upper limb remains, where lymphostasis begins to develop. An exception is the variant of localization of the brachial group of lymph nodes on the posterior surface of the shoulder, in which it is possible to preserve the lateral group of lymph nodes, which does not fall into the block of adipose tissue with other regional lymph nodes, and therefore partially preserve the lymph drainage from the medial surface of the ipsilateral upper limb towards the deltapectoral lymph node. Taking into account the topographic and anatomical variability of the lymph drainage collectors in the axillary fossa and the varied nature of the involvement of lymph nodes in the metastatic process, in each clinical case, the standard preoperative mapping of axillary lymph nodes (reverse lymphatic mapping) does not allow predicting the risk and timing of the development of postoperative upper limb lymphedema. The advantage of our technology two-contrast fluorescent lymphography - is the possibility of visual differentiation of all elements of lymph drainage from the mammary gland (indocyanine green - ICG) and the ipsilateral upper limb (methylene blue - MB). According to the results of the study, it will be possible to clarify the localization of the lateral (shoulder) group of axillary lymph nodes, topographic and anatomical features of the lymphatic drainage collectors in the axillary fossa and indications for lymphovenous shunting for primary surgical prevention of postmastectomy lymphedema of the upper limb.

Role of Doppler ultrasonography in the evaluation of hemodialysis arteriovenous access maturation and influencing factors

The goal of vascular access creation is to achieve a functioning arteriovenous fistula (AVF) or arteriovenous graft (AVG). An autologous fistula has been shown to be superior to AVG or to central venous catheters (CVCs) with lowest rate of re-intervention, but vessel obstruction or immaturity accounts for 20 % to 54% of cases with primary failure of AVF. This review is focused on the factors influencing maturation; indication and timing of preoperative mapping/creation of vascular access; ultrasound parameters for creation AVF/AVG; early postoperative complications following creation of a vascular access; ultrasound determinants of fistula maturation and endovascular intervention in vascular access with maturation failure. However, vascular accesses that fail to develop, have a high incidence of correctable abnormalities, and these need to be promptly recognized by ultrasonography and managed effectively if a high success rate is to be expected. We review approaches to promoting fistula maturation and duplex ultrasonography (DUS) of evaluating vascular access maturation.

Imaging Diagnosis in Colorectal Endometriosis

Colorectal deep infiltrative endometriosis (DIE) can have a major impact on patient’s health and quality of life. Surgical treatment of colorectal DIE varies depending on the location and characteristics of the lesions, which is why the preoperative non-invasive diagnosis needs to be correct and complete. Multiple imaging methods are currently available, but their usefulness is still being studied, as none of them has proven itself perfect. In the present study we wanted to find out to what extent the combined use of magnetic resonance imaging (MRI), endorectal ultrasound (ERUS) and computed tomography-based virtual colonoscopy (CTC) helps perform the preoperative mapping of lesions. We conducted a retrospective study of prospectively collected data that included 49 patients operated for colorectal DIE. In identifying rectal nodules, MRI as a single diagnostic method was the most useful. When ERUS or CTC was added, the concordance between intraoperative and imaging results was very strong. CTC was the most useful in identifying sigmoid nodules. ERUS evaluates the depth of rectal nodules best. CTC assesses best the stenosis for both rectal and sigmoid nodules. Each method contributed to the completion of the diagnosis, so performing ERUS and CTC in addition to MRI seems to be preferable in patients with colorectal DIE.

Role of preoperative ultrasound mapping in the surgical management of deep infiltrating endometriosis: a prospective observational study

Background Endometriosis is a challenging gynecological condition that has a profound influence on the quality of life of affected women. Transvaginal ultrasound is considered the first-line imaging method in preoperative assessment of the extent and severity of endometriosis. Accurate preoperative mapping can aid the surgeon in patient counselling, selection of the most appropriate surgical method that minimizes the operative and post-operative complications. The aim of our study is to evaluate the accuracy of transvaginal sonography (TVS) in precisely assessing the size, location and extent of deep infiltrating endometriosis (DIE) using a new modified endometriosis mapping proforma with histopathological confirmation. Our prospective observational study included 101 women with clinically suspected DIE who underwent TVS followed by laparoscopy from October 2018 to December 2020 with a maximum of 4 weeks interval. Precise mapping of DIE was done during TVS and laparoscopy. Results were correlated with histopathology findings. Results DIE was confirmed by histopathology in 88 patients. Sensitivity and specificity for individual DIE locations were rectovaginal septum 67.9% and 98.6%; vagina 52.2% and 98.7%; uterosacral ligaments 82.5% and 96.2%; torus 96.4% and 97.3%; parametrium 68.8% and 96.9%; rectum 100% and 98.8%; bladder 100% and 100%, ureters 63.4% and 99.0%; scar endometriosis 100% and 100%; pouch of Douglas obliteration 97.7% and 100%. No statistically significant difference was detected between ultrasound and histopathology size. Ultrasound tended to underestimate the lesion size; the underestimation was more pronounced for lesions > 3 cm. “Butterfly” and “tram-track” signs are two new sonographic signs related to posterior compartment DIE. No post-operative complications were recorded. There were no cases of DIE recurrence. Eleven out of 22 cases of infertility achieved pregnancy during 18 months follow-up. Conclusion TVS provides a thorough and accurate evaluation of the extent of endometriosis. An experienced radiologist can use E-PEP to provide an accurate demonstration of the location and extent of DIE which helps the surgeon select the most appropriate surgical approach ensuring radical treatment of the disease and minimizing short- and long-term complications.