Diffusion tensor imaging and tractography to evaluate sacral nerve root abnormalities in endometriosis-related pain: A pilot study

Lumbosacral plexus and pudendal nerve magnetic resonance tractography: A systematic review of the clinical applications for pudendal neuralgia

Diffusion tensor imaging (DTI) is commonly used to establish three-dimensional mapping of white-matter bundles in the supraspinal central nervous system. DTI has also been the subject of many studies on cranial and peripheral nerves. This non-invasive imaging technique enables virtual dissection of nerves in vivo and provides specific measurements of microstructural integrity. Adverse effects on the lumbosacral plexus may be traumatic, compressive, tumoral, or malformative and thus require dedicated treatment. DTI could lead to new perspectives in pudendal neuralgia diagnosis and management. We performed a systematic review of all articles or posters reporting results and protocols for lumbosacral plexus mapping using the DTI technique between January 2011 and December 2023. Twenty-nine articles published were included. Ten studies with a total of 351 participants were able to track the lumbosacral plexus in a physiological context and 19 studies with a total of 402 subjects tracked lumbosacral plexus in a pathological context. Tractography was performed on a 1.5T or 3T MRI system. DTI applied to the lumbosacral plexus and pudendal nerve is feasible but no microstructural normative value has been proposed for the pudendal nerve. The most frequently tracking parameters used in our review are: 3T MRI, b-value of 800 s/mm2, 33 directions, 3 × 3 × 3 mm3, AF threshold of 0.1, minimum fiber length of 10 mm, bending angle of 30°, and 3DT2 TSE anatomical resolution. Increased use of DTI could lead to new perspectives in the management of pudendal neuralgia due to entrapment syndrome, whether at the diagnostic, prognostic, or preoperative planning level. Prospective studies of healthy subjects and patients with the optimal acquisition parameters described above are needed to establish the accuracy of MR tractography for diagnosing pudendal neuralgia and other intrapelvic nerve entrapments.

MRI Features of Pelvic Nerve Involvement in Endometriosis

Endometriosis is a common condition that mostly affects people assigned as female at birth. The most common clinical symptom of endometriosis is pain. Although the mechanism for this pain is poorly understood, in some cases, the nerves are directly involved in endometriosis. Endometriosis is a multifocal disease, and the pelvis is the most common location involved. Nerves in the pelvis can become entrapped and involved in endometriosis. Pelvic nerves are visible at pelvic MRI, especially when imaging planes and sequences are tailored for neural evaluation. In particular, high-spatial-resolution anatomic imaging including three-dimensional isotropic imaging and contrast-enhanced three-dimensional short inversion time inversion-recovery (STIR) fast spin-echo sequences are useful for nerve imaging. The most commonly involved nerves are the sciatic, obturator, femoral, pudendal, and inferior hypogastric nerves and the inferior hypogastric and lumbosacral plexuses. Although it is thought to be rare, the true incidence of nerve involvement in endometriosis is not known. Symptoms of neural involvement include pain, weakness, numbness, incontinence, and paraplegia and may be constant or cyclic (catamenial). Early diagnosis of neural involvement in endometriosis is important to prevent irreversible nerve damage and chronic sensorimotor neuropathy. Evidence of irreversible damage can also be seen at MRI, and radiologists should evaluate pelvic nerves that are commonly involved in endometriosis in their search pattern and report template to ensure that this information is incorporated into treatment planning.

Utility of the Diffusion Weighted Sequence in Gynecological Imaging: Review Article

Simple Summary

Diffusion weighted imaging (DWI) is a magnetic resonance imaging sequence with diverse clinical applications in malignant and nonmalignant gynecological conditions. It provides vital supplemental information in the diagnosis and management of various gynecological conditions. Radiologists should be aware of fundamental concepts, clinical applications and pitfalls of DWI. Additionally we briefly discuss potential scope of newer advanced techniques based on DWI including diffusion tensor imaging and diffusion-weighted whole-body imaging with background signal suppression.

Abstract

Functional imaging with diffusion-weighted imaging (DWI) is a complementary tool to conventional diagnostic magnetic resonance imaging sequences. It is being increasingly investigated to predict tumor response and assess tumor recurrence. We elucidate the specific technical modifications of DWI preferred for gynecological imaging, including the different b-values and planes for image acquisition. Additionally, we discuss the problems and potential pitfalls encountered during DWI interpretation and ways to overcome them. DWI has a wide range of clinical applications in malignant and non-malignant gynecological conditions. It provides supplemental information helpful in diagnosing and managing tubo-ovarian abscess, uterine fibroids, endometriosis, adnexal torsion, and dermoid. Similarly, DWI has diverse applications in gynecological oncology in diagnosis, staging, detection of recurrent disease, and tumor response assessment. Quantitative evaluation with apparent diffusion coefficient (ADC) measurement is being increasingly evaluated for correlation with various tumor parameters in managing gynecological malignancies aiding in preoperative treatment planning. Newer advanced DWI techniques of diffusion tensor imaging (DTI) and whole body DWI with background suppression (DWIBS) and their potential uses in pelvic nerve mapping, preoperative planning, and fertility-preserving surgeries are briefly discussed.

MRI in the Diagnosis of Endometriosis and Related Diseases

Endometriosis, a common chronic inflammatory disease in female of reproductive age, is closely related to patient symptoms and fertility. Because of its high contrast resolution and objectivity, MRI can contribute to the early and accurate diagnosis of ovarian endometriotic cysts and deeply infiltrating endometriosis without the need for any invasive procedure or radiation exposure. The ovaries, which are the most frequent site of endometriosis, can be afflicted by multiple related conditions and diseases. For the diagnosis of deeply infiltrating endometriosis and secondary adhesions among pelvic organs, fibrosis around the ectopic endometrial gland is usually found as a T2 hypointense lesion. This review summarizes the MRI findings obtained for ovarian endometriotic cysts and their physiologically and pathologically related conditions. This article also includes the key imaging findings of deeply infiltrating endometriosis.

Indirect and atypical imaging signals of endometriosis: A wide range of manifestations

Background

Whilst some imaging signs of endometriosis are common and widely accepted as ‘typical’, a range of ‘subtle’ signs could be present in imaging studies, presenting an opportunity to the radiologist and the surgeon to aid the diagnosis and facilitate preoperative surgical planning.

Objective

To summarise and analyse the current information related to indirect and atypical signs of endometriosis by ultrasound (US) and magnetic resonance imaging (MRI).

Methods

Through the use of PubMed and Google scholar, we conducted a comprehensive review of available articles related to the diagnosis of indirect signs in transvaginal US and MRI. All abstracts were assessed and the studies were finally selected by two authors.

Results

Transvaginal US is a real time dynamic exploration, that can reach a sensitivity of 79-94% and specificity of 94%. It allows evaluation of normal sliding between structures in different compartments, searching for adhesions or fibrosis.

MRI is an excellent tool that can reach a sensitivity of 94% and specificity of 77% and allows visualisation of the uterus, bowel loop deviation and peritoneal inclusion cysts. It also allows the categorisation and classification of ovarian cysts, rectovaginal and vesicovaginal septum obliteration, and small bowel endometriotic implants.

Conclusion

The use of an adequate mapping protocol with systematic evaluation and the reporting of direct and indirect signs of endometriosis is crucial for detailed and safe surgical planning.

Effects of Breastfeeding on Endometriosis-Related Pain: A Prospective Observational Study

Endometriosis is a gynecological estrogen-dependent disease whose commonest pain symptoms are dysmenorrhea, dyspareunia, and acyclic chronic pelvic pain (CPP). Hormonal changes occurring during breastfeeding seem to reduce pain and disease recurrence. The aim of this observational prospective study was to assess the effect of breastfeeding on pain and endometriotic lesions in patients with endometriosis and to evaluate a possible correlation between the duration of breastfeeding, postpartum amenorrhea, and pain. Out of 156 pregnant women with endometriosis enrolled, 123 who breastfed were included in the study and were monitored for 2 years after delivery; 96/123 exclusively breastfed for at least 1 month. Mode of delivery, type and duration of breastfeeding, intensity of pain symptoms, and lesion size before pregnancy and during the 24-month follow-up were analyzed. All patients experienced a significant reduction in dysmenorrhea proportional to the duration of breastfeeding. CPP was significantly reduced only in women who exclusively breastfed. No significant improvement in dyspareunia was observed. Ovarian endometriomas were significantly reduced. Therefore, breastfeeding, particularly if exclusive, may cause improvement in dysmenorrhea and CPP proportional to the duration of breastfeeding, as well as a reduction in the size of ovarian endometriomas.

Can New ENZIAN Score 2020 Represent a Staging System Improving MRI Structured Report?

Structured reporting systems for endometriotic disease are gaining a central role in diagnostic imaging: our aim is to evaluate applicability and the feasibility of the recent ENZIAN score (2020) assessed by MRI. A total of 60 patients with suspected tubo–ovarian/deep endometriosis were retrospectively included in our study according to the following criteria: availability of MR examination; histopathological results from laparoscopic or surgical treatment; patients were not assuming estro-progestin or progestin therapy. Three different readers (radiologists with 2-, 5-, and 20-years of experience in pelvic imaging) have separately assigned a score according to the ENZIAN score (revised 2020) for all lesions detected by magnetic resonance imaging (MRI). Our study showed a high interobserver agreement and feasibility of the recent ENZIAN score applied to MRI; on the other hand, our experience highlighted some limitations mainly due to MRI’s inability to assess tubal patency and mobility, as required by the recent score (2020). In view of the limitations which arose from our study, we propose a modified MRI-ENZIAN score that provides a complete structured reporting system, more suitable for MRI. The high interobserver agreement of the recent ENZIAN score applied to MRI confirms its validity as a complete staging system for endometriosis, offering a shared language between radiologists and surgeons.

Modified amino-dextrans as carriers of Gd-chelates for retrograde transport and visualization of peripheral nerves by magnetic resonance imaging (MRI)

Amino-dextrans (AD) conjugated with gadolinium (Gd3+) were developed as neuro-specific contrast agents (CA) for the visualization of the sciatic nerve in rats by magnetic resonance imaging (MRI). AD with 3, 10, and 70 kDa molecular weights were assessed as carrier molecules known to be transported with various speed by axonal microtubules. Detailed spectroscopic characterizations, analyses by Fast Protein Liquid Chromatography (FPLC), Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE), and inductively coupled plasma-mass spectrometry (ICP-MS), were carried out. For MRI, the paramagnetic Gd3+ ion was coupled as a T1 signal enhancer. The well-established linear chelator, diethylenetriaminepentaacetic acid (DTPA), was used and subsequently replaced by the more stable cyclic chelator 1,4,7,10-Tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). In addition, a fluorescently labeled AD-DTPA-Gd was prepared to demonstrate an active transport to the spinal cord by histochemistry. After successful synthesis and characterization, molecular migration of the AD-DTPA-Gd in the sciatic nerve of healthy Sprague Dawley rats was monitored by MRI for up to seven days. Enhancement of nerve structures was evaluated by MRI and correlated with ICP-MS analyses. To investigate the distribution of CA along the neuraxis, all animals were sacrificed after the final MRI monitoring. Nerves, spinal ganglions, and corresponding spinal cord sections were harvested, to determine the localization and concentration of the paramagnetic element. This is the first report that demonstrates the active uptake and transport of AD-Gd conjugates within the sciatic nerve. This new concept may serve as a potential diagnostic tool for the direct visualization and monitoring of the continuity of injured nerves.

Near-infrared intraoperative imaging of pelvic autonomic nerves: a pilot study

BACKGROUND

The pelvic autonomic nerves control and regulate anorectal and urogenital function. The dysfunction of pelvic autonomic nerves lead to disorders of anorectum, bladder and male sex organs. Thus the intraoperative identification of pelvic autonomic nerves could be crucial in complications prevention and diseases treatment. Our clinical trial aims at estimating the effectiveness and validity of intraoperative indocyanine green fluorescence imaging in pelvic autonomic nerves identification.

METHODS

Intraoperative fluorescence imaging using indocyanine green was performed in ten patients and the feasibility was determined. From February 2019 to June 2019, the seven patients undergoing laparoscopic colorectal resection was administrated 4.5 mg/Kg indocyanine green 24 h before surgery. The near-infrared fluorescence imaging was conducted during surgery. A novel white light and near-infrared dual-channel laparoscopic equipment was applied. For each patient, signal-background ratio values for pelvic autonomic nerves were recorded and analyzed.

RESULTS

We confirmed the dose and timing of indocyanine green administration was 4.5 mg/Kg and 24 h before surgery. Using the dual laparoscopic equipment, we could observe the splanchnic plexus, inferior mesenteric artery plexus, and sacral plexus successfully with a high signal background ratio value of 3.18 (standard deviation: 0.48).

CONCLUSION

This pilot trial shows feasibility of intraoperative indocyanine green fluorescence imaging in pelvic autonomic nerves observation. It demonstrates that nerves can be visualized using alternative imaging techniques but it is not ready yet for prime time. This technique might aid observation with white light alone. Registration number: ChiCTR1900025336.

A deep insight into pelvic pain and endometriosis: a review of the literature from pathophysiology to clinical expressions

Endometriosis is a chronic inflammatory disease that affects approximately 10% of women of reproductive age. Its clinical manifestations are highly heterogeneous, but pelvic pain is the most frequent, causing functional disability. Cyclic or acyclic chronic pelvic pain (CPP), dysmenorrhea and dyspareunia are frequent symptoms which often compromise all aspects of the women's quality of life (QoL). The pathophysiology of endometriosis-related pain is extremely complex and not always clear. The aim of this literature review is to focus on recent updates on the clinical presentation, the pathophysiology and the most important mechanisms involved in the pathogenesis of pelvic pain in endometriosis. A literature search in the Cochrane library, PubMed, Scopus and web of Science databases has been performed, identifying articles from January 1995 to November 2020. Several processes seem to be involved in the pathogenesis of pain, but many aspects are still unclear. Scientific evidence has shown that a correlation between pain severity and stage of endometriosis rarely occurs, whereas there is a significant correlation between pain and the presence of deep endometriosis. Onset and intensity of pain may be due to a complex process involving central sensitization and peripheral activation of nociceptive pathways as well as dysfunction of the immune system and of the hypothalamic-pituitary-adrenal (HPA) axis. A deeper understanding of these different pathogenetic mechanisms may improve future treatments in women with painful endometriosis.

Magnetic Resonance Imaging in endometriosis-associated pain

INTRODUCTION

Endometriosis affects 10%-15% of women in reproductive age and may cause no-cyclic chronic pelvic pain, dysmenorrhea, dyspareunia, urinary tract symptoms, and it is frequently associated with infertility. The peak of incidence is between 24 and 29 years old and the clinical diagnosis of endometriosis is generally delayed by 6-7 years. Laparoscopy with surgical biopsies is the "gold standard" for the diagnosis of endometriosis, with histological verification of endometrial ectopic glands and/or stroma. However, nowadays two different non-invasive modalities are routinely used for a presumptive diagnosis: Transvaginal Ultrasound (TVUS) and Magnetic Resonance Imaging (MRI).

EVIDENCE ACQUISITION

A structured search using PubMed was performed starting from October 2020 and including all relevant original and review articles published since 2000. The search used the following key word combinations: "Endometriosis MRI" AND "DIE and MRI" (45); "MRI endometriosis and Pelvic Pain" OR "Endometriosis and MRI technical development" (296). Ultimately, 87 articles were deemed relevant and used as the literature basis of this review.

EVIDENCE SYNTHESIS

TVUS represents the first imaging approach for endometriosis showing a good diagnostic performance but it is highly operator dependent. MRI is a second level examination often used in complex cases indeterminate after TVUS and in pre-operative planning. MRI is considered the best imaging technique for mapping endometriosis since it provides a more reliable map of deep infiltrating endometriosis than physical examination and transvaginal ultrasound. We have analyzed and described the main forms of endometriosis: adnexal endometriosis, adenomyosis, peritoneal implants and deep infiltrating endometriosis, showing their appearance in the two imaging modalities.

CONCLUSIONS

Endometriosis is one of the most common gynecologic disorders correlated to chronic pelvic pain whose treatment is still today complex and controversial. In this context, MRI has become an important additional non-invasive tool to investigate cases of chronic pelvic pain related to deep infiltrating endometriosis (DIE) with or without neural involvement.

The Usefulness of Diffusion Tensor Tractography in Diagnosing Neuropathic Pain: A Narrative Review

Diffusion tensor tractography (DTT) is derived from diffusion tensor imaging. It has allowed visualization and estimation of neural tract injury, which may be associated with the pathogenesis of neuropathic pain (NP). The aim of the present study was to review DTT studies that demonstrated the relationship between neural injuries and NP and to describe the potential use of DTT in the evaluation of neural injuries that are involved in the pathophysiological process of NP. A PubMed search was conducted for articles published until July 3, 2020, which used DTT to investigate the association between neural injuries and NP. The key search phrase for identifying potentially relevant articles was (diffusion tensor tractography AND pain). The following inclusion criteria were applied for article selection: (1) studies involving patients with NP and (2) studies in which DTT was applied for the evaluation of NP. Review articles were excluded. Altogether, 108 potentially relevant articles were identified. After reading the titles and abstracts and assessment of eligibility based on the full-text articles, 46 publications were finally included in our review. The results of the included studies suggested that DTT may be beneficial in identifying the pathophysiological mechanism of NP of various origins including central pain caused by brain injuries, trigeminal neuralgia, sciatica, and some types of headache. Further studies are needed to validate the efficacy of DTT in investigating the pathophysiology of other types of NP.

Mapping the rest of the human connectome: Atlasing the spinal cord and peripheral nervous system

The emergence of diffusion, structural, and functional neuroimaging methods has enabled major multi-site efforts to map the human connectome, which has heretofore been defined as containing all neural connections in the central nervous system (CNS). However, these efforts are not structured to examine the richness and complexity of the peripheral nervous system (PNS), which arguably forms the (neglected) rest of the connectome. Despite increasing interest in an atlas of the spinal cord (SC) and PNS which is simultaneously stereotactic, interactive, electronically dissectible, scalable, population-based and deformable, little attention has thus far been devoted to this task of critical importance. Nevertheless, the atlasing of these complete neural structures is essential for neurosurgical planning, neurological localization, and for mapping those components of the human connectome located outside of the CNS. Here we recommend a modification to the definition of the human connectome to include the SC and PNS, and argue for the creation of an inclusive atlas to complement current efforts to map the brain's human connectome, to enhance clinical education, and to assist progress in neuroscience research. In addition to providing a critical overview of existing neuroimaging techniques, image processing methodologies and algorithmic advances which can be combined for the creation of a full connectome atlas, we outline a blueprint for ultimately mapping the entire human nervous system and, thereby, for filling a critical gap in our scientific knowledge of neural connectivity.

Sciatic endometriosis: A narrative review of an unusual neurogynecologic condition

Endometriosis is a condition in which there is an ectopic growth of endometrial tissue. Sciatic endometriosis, otherwise known as catamenial sciatica, is a rare but exceedingly significant presentation of endometriosis. Symptoms include cyclic sciatic pain that peaks during the menstrual period; additionally, paresthesia, paresis, and areflexia may occur with this condition. Sciatic endometriosis can be presumptively diagnosed in response to empiric treatment (e.g. gonadotropin-releasing hormone analogs) or imaging studies, but a definitive diagnosis of sciatic endometriosis may occur from examining tissue obtained during surgery. Surgical removal of endometriosis from the sciatic nerve root can potentially eliminate symptoms while maintaining normal reproductive function, though poses particular surgical risks. Familiarity with this rare condition is paramount to making this diagnosis and the initiation of earlier treatment.

MRI for the diagnosis and staging of deeply infiltrating endometriosis: a national survey of BSGE accredited endometriosis centres and review of the literature

OBJECTIVES

Our objective was to establish the primary mode of imaging and MR protocols utilised in the preoperative staging of deeply infiltrating endometriosis in centres accredited by the British Society of Gynaecological Endoscopy (BSGE).

METHODS

The lead consultant radiologist in each centre was invited to complete an online survey detailing their protocols.

RESULTS

Out of 49 centres, 32 (65%) responded to the survey. Two centres performed transvaginal ultrasound as the primary method for preoperative staging of deeply infiltrating endometriosis and the remainder performed MRI. 21/25 centres did not recommend a period of fasting prior to MRI and 22/25 administered hyoscine butylbromide. None of the centres routinely offered bowel preparation or recommended a specific pre-procedure diet. 21/25 centres did not time imaging according to the woman's menstrual cycle, and instructions regarding bladder filling were varied. Rectal and vaginal opacification methods were infrequently utilised. All centres preferentially performed MRI in the supine position - six used an abdominal strap and four could facilitate prone imaging. Just under half of centres used pelvic-phased array coils and three centres used gadolinium contrast agents routinely. All centres performed T1W with fat-suppression and T2W without fat-suppression sequences. There was significant variation relating to other MR sequences depending on the unit.

CONCLUSIONS

There was significant inconsistency between centres in terms of MR protocols, patient preparation and the sequences performed. Many practices were out of line with current published evidence.

ADVANCES IN KNOWLEDGE

Our survey demonstrates a need for evidence-based standardisation of imaging in BSGE accredited endometriosis centres.

Irritable Bowel Syndrome-Like Disorders in Endometriosis: Prevalence of Nickel Sensitivity and Effects of a Low-Nickel Diet. An Open-Label Pilot Study

Alimentary nickel (Ni) may result in allergic contact mucositis (ACM), whose prevalence is >30% and may present with IBS-like and extra-intestinal symptoms. These symptoms are also frequent in endometriosis, and Ni allergic contact dermatitis has already been observed in endometriosis. Therefore, intestinal and extra-intestinal symptoms in endometriosis may depend on a Ni ACM, and a low-Ni diet could improve symptoms. We studied the prevalence of Ni ACM in endometriosis and focused on the effects of a low-Ni diet on gastrointestinal, extra-intestinal, and gynecological symptoms. We recruited 84 women with endometriosis, symptomatic for gastrointestinal disorders. Thirty-one out of 84 patients completed the study. They underwent Ni oral mucosa patch test (omPT), questionnaire for intestinal/extra-intestinal/gynecological symptoms, and a low-Ni diet. Clinical evaluation was performed at baseline (T0) and after three months (T1). Twenty-eight out 31 (90.3%) patients showed Ni omPT positive results, with Ni ACM diagnosis, whereas three out of 31 (9.7%) patients showed negative Ni omPT. After three months of low-Ni diet, all gastrointestinal, extra-intestinal and gynecological symptoms showed a statistically significant reduction. Ni ACM has a high prevalence in endometriosis and a low-Ni diet may be recommended in this condition to reduce gastrointestinal, extra-intestinal and gynecological symptoms.

Extrapelvic Sciatic Nerve Endometriosis, the Role of Magnetic Resonance Imaging: Case Report and Systematic Review

Endometriosis (EN) is a common gynecological condition characterized by the presence of functional endometrium located outside the uterine cavity. Sciatic nerve (SN) is rarely affected by EN. Magnetic resonance imaging allows a direct visualization of the spinal and SN, and it is the modality of choice for the study of SN involvement in extrapelvic EN. We report a case of an endometrioma located in the right SN with a systematic review of the literature.

Fractalkine/CX3CR1 Contributes to Endometriosis-Induced Neuropathic Pain and Mechanical Hypersensitivity in Rats

Pain is the most severe and common symptom of endometriosis. Its underlying pathogenetic mechanism is poorly understood. Nerve sensitization is a particular research challenge, due to the limitations of general endometriosis models and sampling nerve tissue from patients. The chemokine fractalkine (FKN) has been demonstrated to play a key role in various forms of neuropathic pain, while its role in endometriotic pain is unknown. Our study was designed to explore the function of FKN in the development and maintenance of peripheral hyperalgesia and central sensitization in endometriosis using a novel endometriosis animal model developed in our laboratory. After modeling, behavioral tests were carried out and the optimal time for molecular changes was obtained. We extracted ectopic tissues and L4-6 spinal cords to detect peripheral and central roles for FKN, respectively. To assess morphologic characteristics of endometriosis-like lesions-as well as expression and location of FKN/CX3CR1-we performed H&E staining, immunostaining, and western blotting analyses. Furthermore, inhibition of FKN expression in the spinal cord was achieved by intrathecal administration of an FKN-neutralizing antibody to demonstrate its function. Our results showed that implanted autologous uterine tissue around the sciatic nerve induced endometriosis-like lesions and produced mechanical hyperalgesia and allodynia. FKN was highly expressed on macrophages, whereas its receptor CX3CR1 was overexpressed in the myelin sheath of sciatic nerve fibers. Overexpressed FKN was also observed in neurons. CX3CR1/pp38-MAPK was upregulated in activated microglia in the spinal dorsal horn. Intrathecal administration of FKN-neutralizing antibody not only reversed the established mechanical hyperalgesia and allodynia, but also inhibited the expression of CX3CR1/pp38-MAPK in activated microglia, which was essential for the persistence of central sensitization. We concluded that the FKN/CX3CR1 signaling pathway might be one of the mechanisms of peripheral hyperalgesia in endometriosis, which requires further studies. Spinal FKN is important for the development and maintenance of central sensitization in endometriosis, and it may further serve as a novel therapeutic target to relieve persistent pain associated with endometriosis.

The Role of Magnetic Resonance Imaging-Diffusion Tensor Imaging in Predicting Pain Related to Endometriosis: A Preliminary Study

OBJECTIVES

To evaluate the sacral nerve root features by the means of magnetic resonance imaging-diffusion tensor imaging (MRI-DTI) tractography in women with endometriosis and/or adenomyosis, and to analyze the correlations among DTI abnormalities, pain symptoms, and endometriotic lesions found at surgery.

DESIGN

A cross-sectional, observational study (Canadian Task Force classification II-2).

SETTING

University hospital.

PATIENTS

Women (n = 76) with clinical suspicion of endometriosis.

INTERVENTIONS

Before surgery, dysmenorrhea, deep dyspareunia, and noncyclic pelvic pain (NCPP) were assessed using a 10-point visual analog scale. MRI enabled a 3-dimensional reconstruction of S1, S2, and S3. Fractional anisotropy was calculated for each root. Laparoscopic treatment of endometriosis was performed in 56 patients.

MEASUREMENTS AND MAIN RESULTS

Our findings revealed correlations among sacral root reconstruction by MRI-DTI, pain symptoms, and laparoscopic findings. DTI of sacral roots revealed a regular and homogeneous appearance in 17 patients (25.8%) and abnormalities in microstructure reconstruction, with fiber irregularities and disorganization and loss of the simple unidirectional course, in 44 patients (66.7%). At laparoscopy, ovarian endometriomas were found in 82.1% of the patients, and deeply infiltrating endometriosis (DIE) were found in 57.1%. Endometriosis was staged according to the revised American Society for Reproductive Medicine classification. Pathological DTI findings were significantly associated with the severity of dysmenorrhea and NCPP, pain duration, presence of tubo-ovarian and cul-de-sac adhesions, and DIE.

CONCLUSION

The presence of pathological DTI findings of the sacral nerve roots correlates with the type of pain, adhesions, and DIE. At present, DTI can be useful for providing a better understanding of pain; however, DTI could become a useful tool in therapeutic planning for patients with endometriosis.

Shining light in a dark landscape: MRI evaluation of unusual localization of endometriosis

Endometriosis is a disease distinguished by the presence of endometrial tissue outside the uterine cavity with intralesional recurrent bleeding and resulting fibrosis. The most common locations for endometriosis are the ovaries, pelvic peritoneum, uterosacral ligaments, and torus uterinus. Typical symptoms are secondary dysmenorrhea and cyclic or chronic pelvic pain. Unusual sites of endometriosis may be associated with specific symptoms depending on the localization. Atypical pelvic endometriosis localizations can occur in the cervix, vagina, round ligaments, ureter, and nerves. Moreover, rare extrapelvic endometriosis implants can be localized in the upper abdomen, subphrenic fold, or in the abdominal wall. Magnetic resonance imaging (MRI) represents a problem-solving tool among other imaging modalities. MRI is an advantageous technique, because of its multiplanarity, high contrast resolution, and lack of ionizing radiation. Our purpose is to remind the radiologists the possibility of atypical pelvic and extrapelvic endometriosis localizations and to illustrate the specific MRI findings. Endometriotic tissue with hemorrhagic content can be distinguished from adherences and fibrosis on MRI imaging. Radiologists should keep in mind these atypical localizations in patients with suspected endometriosis, in order to achieve the diagnosis and to help the clinicians in planning a correct and complete treatment strategy.

Pudendal nerve and branch neuropathy: magnetic resonance neurography evaluation

Pudendal neuralgia is being increasingly recognized as a cause of chronic pelvic pain, which may be related to nerve injury or entrapment. Due to its complex anatomy and branching patterns, the pudendal nerve abnormalities are challenging to illustrate. High resolution 3 T magnetic resonance neurography is a promising technique for the evaluation of peripheral neuropathies. In this article, the authors discuss the normal pudendal nerve anatomy and its variations, technical considerations of pudendal nerve imaging, and highlight the normal and abnormal appearances of the pudendal nerve and its branches with illustrative case examples.

Research Priorities for Endometriosis

The 3rd International Consensus Workshop on Research Priorities in Endometriosis was held in São Paulo on May 4, 2014, following the 12th World Congress on Endometriosis. The workshop was attended by 60 participants from 19 countries and was divided into 5 main sessions covering pathogenesis/pathophysiology, symptoms, diagnosis/classification/prognosis, disease/symptom management, and research policy. This research priorities consensus statement builds on earlier efforts to develop research directions for endometriosis. Of the 56 research recommendations from the 2011 meeting in Montpellier, a total of 41 remained unchanged, 13 were updated, and 2 were deemed to be completed. Fifty-three new research recommendations were made at the 2014 meeting in Sao Paulo, which in addition to the 13 updated recommendations resulted in a total of 66 new recommendations for research. The research recommendations published herein, as well as those from the 2 previous papers from international consensus workshops, are an attempt to promote high-quality research in endometriosis by identifying and agreeing on key issues that require investigation. New areas included in the 2014 recommendations include infertility, patient stratification, and research in emerging nations, in addition to an increased focus on translational research. A revised and updated set of research priorities that builds on this document will be developed at the 13th World Congress on Endometriosis to be held on May 17-20, 2017, in Vancouver, British Columbia, Canada.

European society of urogenital radiology (ESUR) guidelines: MR imaging of pelvic endometriosis

Abstract

Endometriosis is a common gynaecological condition of unknown aetiology that primarily affects women of reproductive age. The accepted first-line imaging modality is pelvic ultrasound. However, magnetic resonance imaging (MRI) is increasingly performed as an additional investigation in complex cases and for surgical planning. There is currently no international consensus regarding patient preparation, MRI protocols or reporting criteria. Our aim was to develop clinical guidelines for MRI evaluation of pelvic endometriosis based on literature evidence and consensus expert opinion. This work was performed by a group of radiologists from the European Society of Urogenital Radiology (ESUR), experts in gynaecological imaging and a gynaecologist expert in methodology. The group discussed indications for MRI, technical requirements, patient preparation, MRI protocols and criteria for the diagnosis of pelvic endometriosis on MRI. The expert panel proposed a final recommendation for each criterion using Oxford Centre for Evidence Based Medicine (OCEBM) 2011 levels of evidence.

Key Points

• This report provides guidelines for MRI in endometriosis.

• Minimal and optimal MRI acquisition protocols are provided.

• Recommendations are proposed for patient preparation, best MRI sequences and reporting criteria.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-016-4673-z) contains supplementary material, which is available to authorized users.

Magnetic Resonance Neurography of the Pelvic Nerves

Chronic pelvic pain syndrome is commonly caused by nerve injury, inflammation, or entrapment. Owing to the complex anatomy and branching patterns of pelvic nerves, pelvic neuropathies are often difficult to illustrate and diagnose. High-resolution 3-T magnetic resonance neurography is a promising technique for the evaluation of peripheral neuropathy. In this article, the authors discuss the normal anatomy of major pelvic nerves, technical considerations of high-resolution imaging, and normal and abnormal imaging appearances with relevant case examples.

Evaluation of the sacral nerve plexus in pelvic endometriosis by three-dimensional MR neurography

PURPOSE

To investigate the feasibility of three-dimensional MR neurography (3D MRN) for the sacral plexus using sampling perfection with application-optimized contrasts using different flip angle evolution (SPACE) sequences, and to demonstrate structural abnormalities in the pelvic nerve of women with pelvic endometriosis.

MATERIALS AND METHODS

Twenty patients with pelvic endometriosis and 20 healthy controls were examined by contrast-enhanced 3D short time inversion recovery T2-weighted imaging (CE 3D STIR T2WI) SPACE sequences on 3 Tesla MRI. Image quality and diagnostic confidence of the sequences in identifying abnormalities of the sacral plexus were analyzed and compared with conventional three-plane images of 2D turbo-spin echo T2-weighted images (2D TSE T2WI). The changes in the sacral plexus caused by endometrial lesions were evaluated.

RESULTS

The sacral plexus was clearly revealed in both healthy controls and patients with endometriosis on 3D STIR SPACE images. A good agreement was reached in the evaluation of both imaging quality (Kappa value [κ] = 0.73-1.00) and diagnostic confidence (κ = 0.66-0.81) when compared between the two independent readers. Abnormalities caused by endometriosis were identified in 17 patients, unilaterally in 10 patients, and bilaterally in 7 patients. Nerve fiber abnormalities of lumbar 5 (L5) were detected in 11 patients, of sacral 1 (S1) in 14 patients and of sacral 2 (S2) in 9 patients.

CONCLUSION

CE 3D STIR SPACE sequences demonstrate its significant capacity to investigate and map the sacral plexus, and reveal the compression and adhesion of the sacral plexus nerve as a result of ectopic lesions.

LEVEL OF EVIDENCE

3 J. Magn. Reson. Imaging 2017;45:1225-1231.

Microstructural Changes in Compressed Nerve Roots Are Consistent With Clinical Symptoms and Symptom Duration in Patients With Lumbar Disc Herniation

STUDY DESIGN

A prospective study.

OBJECTIVE

To investigate the association between microstructural nerve roots changes on diffusion tensor imaging (DTI) and clinical symptoms and their duration in patients with lumbar disc herniation.

SUMMARY OF BACKGROUND DATA

The ability to identify microstructural properties of the nervous system with DTI has been demonstrated in many studies. However, there are no data regarding the association between microstructural changes evaluated using DTI and symptoms assessed with the Oswestry Disability Index (ODI) and their duration.

METHODS

Forty consecutive patients with foraminal disc herniation affecting unilateral sacral 1 (S1) nerve roots were enrolled in this study. DTI with tractography was performed on the S1 nerve roots. Clinical symptoms were evaluated using an ODI questionnaire for each patient, and the duration of clinical symptoms was noted based on the earliest instance of leg pain and numbness. Mean fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values were calculated from tractography images.

RESULTS

The mean FA value of the compressed lumbar nerve roots was significantly lower than the FA of the contralateral nerve roots (P < 0.001). No notable difference in ADC was observed between compressed nerve roots and contralateral nerve roots (P = 0.517). In the compressed nerve roots, a significant negative association was observed between FA values and ODI and symptom duration. However, an obvious positive association was observed between ODI and ADC values and duration on the compressed side.

CONCLUSION

Significant changes in diffusion parameters were found in the compressed sacral nerves in patients with lumbar disc herniation and leg pain, indicating that the microstructure of the nerve root has been damaged.

LEVEL OF EVIDENCE

3.

Noninvasive imaging of peripheral nerves

Recent developments in the field of peripheral nerve imaging extend the capabilities of imaging modalities to assist in the diagnosis and treatment of patients with peripheral nerve maladies. Methods such as magnetic resonance imaging (MRI) and its derivative diffusion tensor imaging (DTI), ultrasound (US) and positron emission tomography (PET) are capable of assessing nerve structure and function following injury and relating the state of the nerve to electrophysiological and histological analysis. Of the imaging methods surveyed here, each offered unique and interesting advantages related to the field. MRI offered the opportunity to visualize immune activity on the injured nerve throughout the course of the regeneration process, and DTI offered numerical characterization of the injury and the ability to develop statistical bases for diagnosing injury. US extends imaging to the treatment phase by enabling more precise analgesic applications following surgery, and PET represents a novel method of assessing nerve injury through analysis of relative metabolism rates in injured and healthy tissue. Exciting new possibilities to enhance and extend the abilities of imaging methods are also discussed, including innovative contrast agents, some of which enable multimodal imaging approaches and present opportunities for treatment application.

Increased dose single-agent gemcitabine in platinum-taxane resistant metastatic ovarian cancer

CONCLUSION

In platinum–taxane resistant epithelial ovarian cancer (EOC), we aimed to determine the effectiveness.

PATIENTS AND METHODS

Between 2004 and 2013, patients afflicted with platinum–taxane resistant EOC and who were administered a 30-minute i.v. infusion of single-agent gemcitabine at a dose of 1,250 mg/m2 on the 1st, 8th and 15th days, every 28 days, were examined retrospectively.

RESULTS

Twenty-six patients with platinum–taxane resistant EOC were included in the study. The overall survival (OS) was 48 months. The median survival after becoming platinum–taxane resistant was 16 months for the study population. Median time to progression (TTP) and median survival after becoming platinum–taxane resistant for patients who received second-line treatment were 3.3 months and 16 months, respectively; for patients who received third-line treatment with gemcitabine, these were 3.7 months and 19 months, respectively. Administration of gemcitabine as second- and third-line chemotherapy in platinum–taxane resistant EOC, provides similar TTP and OS outcomes (p = 0.4, p = 0.9) with a similar response and toxicity rate.

CONCLUSIONS

Second- and third-line gemcitabine at a dose of 1,250 mg/m2 on days 1, 8 and 15 every 28 days as a 30-minute i.v. infusion in platinum–taxane resistant EOC is an effective treatment option with a tolerable and manageable toxicity.

Completing the Pain Circuit: Recent Advances in Imaging Pain and Inflammation beyond the Central Nervous System

This review describes some of the recent developments in imaging aspects of pain in the periphery. It is now possible to image nerves in the cornea non-invasively, to image receptor level expression and inflammatory processes in injured tissue, to image nerves and alterations in nerve properties, to image astrocyte and glial roles in neuroinflammatory processes, and to image pain conduction functionally in the trigeminal ganglion. These advances will ultimately allow us to describe the pain pathway, from injury site to behavioral consequence, in a quantitative manner. Such a development could lead to diagnostics determining the source of pain (peripheral or central), objective monitoring of treatment progression, and, hopefully, objective biomarkers of pain.