Lymphatic Channels Research Articles

Lymphangioma of popliteal fossa masquerading as Baker\u2019s cyst

BackgroundLymphatic malformations are the second most common vascular malformations after venous malformations. These slow-flow lesions occur most often in the paediatric population and seldom in the extremities. We report a case of lymphangioma at the popliteal fossa in an adult who underwent complete surgical resection.Case presentationA 30-year-old male presented to the department of orthopaedics with a swelling in the right calf region. Clinically, it was suspected to be a Baker’s cyst. Ultrasound showed a multiloculated anechoic cystic lesion in the inferior aspect of popliteal fossa along the intermuscular plane with multiple internal septations. Infected Baker’s cyst was considered, and MRI was suggested for further evaluation. On MRI, the lesion measured 7.2 × 4.6 × 5.8 cm, appeared as a low signal on T1 and high signal on STIR and T2, with multiple internal septations and was situated in the inferior aspect of the right popliteal fossa along the intermuscular plane between the lateral head of gastrocnemius and soleus muscles. No obvious synovial extension. A post-contrast study showed minimal peripheral and septal enhancement. Neither internal enhancing solid components nor significant internal derangement of the knee was observed. Diagnosis of lymphangioma was considered based on the imaging features and ruling out the common differentials for cystic lesions around the knee. Wide local excision was performed. Histopathological evaluation showed multiple irregularly dilated lymphatic channels lined by flatted epithelium. The lymphatic channels were seen to be surrounded by thick fibro collagenous cyst wall with scattered congested blood vessels, skeletal muscle fibre and chronic inflammatory cells.ConclusionLymphangioma must be included in the differential diagnosis of any cystic lesion if the lesion appears multiseptated and/or infiltrative. At the popliteal fossa, it presents as a multiseptated cyst with no synovial continuity or internal derangement of the knee.

Lymph-Derived Neutrophils Primarily Locate to the Subcapsular and Medullary Sinuses in Resting and Inflamed Lymph Nodes.

Neutrophils are the first immune cells to be recruited from the blood to the tissue site of an infection or inflammation. It has been suggested that neutrophils are capable of migrating from the infected tissue via lymphatic vessels to the draining lymph nodes. However, it remains elusive as to which areas within the lymph nodes can be reached by such reversely migrating cells. To address this question, we applied a model for adoptive neutrophil transfer into the afferent lymphatic vessel that drains towards the popliteal lymph node in mice. We showed that resting and in vitro-activated neutrophils did not enter the lymph node parenchyma but localized primarily in the subcapsular and medullary sinuses. Within the medulla, neutrophils show random migration and are able to sense laser-induced sterile tissue injury by massively swarming to the damaged tissue site. Co-injected dendritic cells supported the entry of resting neutrophils into the lymph node parenchyma via the subcapsular sinus. In contrast, in vivo-activated adoptively transferred neutrophils were capable of migrating into the interfollicular areas of the lymph node. Collectively, the data presented here give further insights into the functional behavior of neutrophils within the lymph nodes.

Anasarca in an Infant – An Unusual Cause

ObjectivesPrimary intestinal lymphangiectasia is a rare cause of protein losing enteropathy. It is usually seen in children less than 3 years of age. The disease is characterised by dilatation and engorgement of lymphatics in the small bowel due to congenital malformation of lymphatic channel or hypoplasia of lymphatics. MethodsA 10 month old female child was admitted with a h/o persistent diarrhoea and generalised swelling of the body for 15 days. She was exclusively breastfed till 6 months, complementary feeding started thereafter. On examination, both eyelids were edematous with b/l pedal edema and abdominal distension. Investigations showed hypoalbuminemia, hypoproteinemia and thrombocytosis. Urine, stool examination and spot urine protein creatinine ratio were normal. USG abdomen showed mild ascites and edematous bowel loops. UGI endoscopy and biopsy showed multiple fragments of duodenal mucosa with subepithelium showing multiple dilated lymphatic spaces. The child was started on high protein, low fat diet with MCT, vitamin D, zinc and FFP transfusion. Child improved clinically with reduced edema and loose stools, hence discharged. I/v/o persistent thrombocytosis, we considered possibility of a rare syndrome, CHAPLE (Complement hyperactivation, Angiopathic Thrombosis and Protein losing enteropathy). However, CD55 level was normal and hence we also considered further evaluation for non -CHAPLE PIL but genetic work up could not be done. ResultsPIL should be considered as one of the differential diagnosis in a child presenting with anasarca. The main modality of treatment in our case was high protein, low fat diet and MCT supplements. Child was on regular follow up with pediatric gastroenterologist for about 3 months. Mother reported the baby had persistent loose stools and was treated at home and died before reaching a hospital. We have heard in literature about good outcomes in PIL as well as frequent relapses with chronicity. This acute life threatening event in PIL needs to be discussed regarding possibility of any thrombosis secondary to dehydration and thrombocytosis. ConclusionsPIL is a rare condition seen in children less than 3 years. Early diagnosis with endoscopic visualization of the gut and biopsy of the small bowel may play a great role. Mainstay of treatment is high-protein, low fat diet with MCT supplement. Funding SourcesNone.

Structure and Immune Function of Afferent Lymphatics and Their Mechanistic Contribution to Dendritic Cell and T Cell Trafficking.

Afferent lymphatic vessels (LVs) mediate the transport of antigen and leukocytes to draining lymph nodes (dLNs), thereby serving as immunologic communication highways between peripheral tissues and LNs. The main cell types migrating via this route are antigen-presenting dendritic cells (DCs) and antigen-experienced T cells. While DC migration is important for maintenance of tolerance and for induction of protective immunity, T cell migration through afferent LVs contributes to immune surveillance. In recent years, great progress has been made in elucidating the mechanisms of lymphatic migration. Specifically, time-lapse imaging has revealed that, upon entry into capillaries, both DCs and T cells are not simply flushed away with the lymph flow, but actively crawl and patrol and even interact with each other in this compartment. Detachment and passive transport to the dLN only takes place once the cells have reached the downstream, contracting collecting vessel segments. In this review, we describe how the anatomy of the lymphatic network supports leukocyte trafficking and provide updated knowledge regarding the cellular and molecular mechanisms responsible for lymphatic migration of DCs and T cells. In addition, we discuss the relevance of DC and T cell migration through afferent LVs and its presumed implications on immunity.

Pilot study supporting the existence of novel lymphatic channels within the canine anterior uveal tract using Lyve-1 and CD31.

To demonstrate the existence of lymphatics in the canine anterior uvea using lymphatic-specific markers Lyve-1, Prox-1, and podoplanin, the endothelial cell marker CD31, and basement membrane matrix marker collagen IV. Prospective Study. Eight normal globes from animals euthanized for unrelated health problems. Sagittally cut serial sections of six normal canine eyes were immunofluorescence double-stained with Lyve-1 and CD31 and single-stained with colorimetric Prox-1 and collagen IV. Three serial sections from 2 additional eyes were cut in the coronal plane at the level of the ciliary body and immunofluorescence double-stained with Lyve-1 and CD31 to map lymphatic channel distribution. Lymphatics from normal canine lymph nodes were used for validation of podoplanin. Four of 6 of the sagitally sectioned eyes had Lyve-1-positive lymphatic-like structures that were distinct from CD31-positive blood vessels in the iris base and ciliary body. Both of the coronally sectioned globes had Lyve-1-positive lymphatic-like structures in the ciliary body. The location of these structures was evaluated and found to be diffusely present circumferentially around the ciliary body. These results support the existence of lymphatic channels in the anterior uveal tract of the canine eye. This could indicate the presence of a novel uveolymphatic outflow pathway, which may play a role in aqueous humor outflow. Future studies are needed to confirm the existence and elucidate the role of this proposed uveolymphatic outflow pathway and potentially develop novel treatment options for managing glaucoma.

Cancer microenvironment and genomics: evolution in process.

Cancer heterogeneity is a result of genetic mutations within the cancer cells. Their proliferation is not only driven by autocrine functions but also under the influence of cancer microenvironment, which consists of normal stromal cells such as infiltrating immune cells, cancer-associated fibroblasts, endothelial cells, pericytes, vascular and lymphatic channels. The relationship between cancer cells and cancer microenvironment is a critical one and we are just on the verge to understand it on a molecular level. Cancer microenvironment may serve as a selective force to modulate cancer cells to allow them to evolve into more aggressive clones with ability to invade the lymphatic or vascular channels to spread to regional lymph nodes and distantsites. It is important to understand these steps of cancer evolution within the cancer microenvironment towards invasion so that therapeutic strategies can be developed to control or stop these processes.

LN-Derived Fibroblastic Reticular Cells and Their Impact on T Cell Response-A Systematic Review.

Fibroblastic reticular cells (FRCs), usually found and isolated from the T cell zone of lymph nodes, have recently been described as much more than simple structural cells. Originally, these cells were described to form a conduit system called the “reticular fiber network” and for being responsible for transferring the lymph fluid drained from tissues through afferent lymphatic vessels to the T cell zone. However, nowadays, these cells are described as being capable of secreting several cytokines and chemokines and possessing the ability to interfere with the immune response, improving it, and also controlling lymphocyte proliferation. Here, we performed a systematic review of the several methods employed to investigate the mechanisms used by fibroblastic reticular cells to control the immune response, as well as their ability in determining the fate of T cells. We searched articles indexed and published in the last five years, between 2016 and 2020, in PubMed, Scopus, and Cochrane, following the PRISMA guidelines. We found 175 articles published in the literature using our searching strategies, but only 24 articles fulfilled our inclusion criteria and are discussed here. Other articles important in the built knowledge of FRCs were included in the introduction and discussion. The studies selected for this review used different strategies in order to access the contribution of FRCs to different mechanisms involved in the immune response: 21% evaluated viral infection in this context, 13% used a model of autoimmunity, 8% used a model of GvHD or cancer, 4% used a model of Ischemic-reperfusion injury (IRI). Another four studies just targeted a particular signaling pathway, such as MHC II expression, FRC microvesicles, FRC secretion of IL-15, FRC network, or ablation of the lysophosphatidic acid (LPA)-producing ectoenzyme autotaxin. In conclusion, our review shows the strategies used by several studies to isolate and culture fibroblastic reticular cells, the models chosen by each one, and dissects their main findings and implications in homeostasis and disease.

Papillary Thyroid Carcinoma With Axillary Lymph Node Metastasis

Papillary thyroid carcinoma (PTC) is typically known to be a non-aggressive form of thyroid follicular epithelial-derived cancer. It is characterized histologically by classic and variant forms. Metastases are uncommon and spread mainly via lymphatic channels to cervical lymph nodes and less commonly via hematogenous spread to lungs and bone. Axillary lymph node (ALN) metastasis is a rare sequela of disease presentation. A 59-year-old female presented for evaluation of shortness of breath and chest pain for one week. She had a longstanding history of hypothyroidism due to chronic lymphocytic thyroiditis which was stable on levothyroxine. Her physical exam revealed a firm mass on the inferior aspect of the left neck. Computed tomography (CT) angiogram ruled out pulmonary embolism but noted a superior mediastinal mass and significant left axillary and subpectoral adenopathy. Mammogram was negative for breast malignancy. Left axillary ultrasound showed a 1.1 x 1.8 x 1.9 cm enlarged lymph node. Thyroid ultrasound showed a 3 mm nodule on the left lower pole and a 3.7 x 2.9 x 2.1 cm heterogeneous and irregular mass in the left neck. Positron emission tomography/CT showed increased uptake in left lower paratracheal, left supraclavicular and axillary lymph nodes. Fine needle aspiration of the left neck mass and left ALN confirmed metastatic papillary carcinoma. She underwent total thyroidectomy, left modified neck, central neck, and left ALN dissection along with partial esophageal wall excision. Intraoperatively, she was found to have a multifocal tumor in the left thyroid lobe with the largest dimension of 1 cm. Surgical pathology noted that the primary tumor in the left thyroid was classic type of papillary carcinoma, and the metastatic tumor in the lymph nodes was of tall cell variant. I-123 thyroid uptake and scan after surgery showed low residual thyroid uptake of 0.6%. She underwent adjuvant ablation with 155 millicuries (mCi) of radioiodine (RAI or I-131) following levothyroxine withdrawal protocol. Post ablation therapy thyroid uptake and scan showed no radiotracer uptake within the thyroidectomy bed. According to the American thyroid association (ATA) risk stratification system, she was categorized as high risk. This case illustrates that PTC may exceptionally spread to axillary lymph nodes. Physiologic flow is centripetal to the jugulosubclavian junction and there is no communication between cervical and axillary lymphatics. However malignant tumors can alter and partially block lymphatic pathways, resulting in ALN metastasis in a retrograde direction. This case also demonstrates that PTC can be transformed into aggressive forms associated with worse prognosis such as tall cell variant. Further comprehensive monitoring and management approaches are needed to plan treatment and gauge prognosis of patients with PTC who present with ALN metastasis.

Efficacy of local hyaluronidase administration in guided bone regeneration surgery: a randomized controlled trial.

ObjectivesHyaluronoglucosaminidase (hyaluronidase) increases the local intercellular permeability of the peripheral lymphatic channel and capillaries, which may help reduce edema. In the present study, the effects of hyaluronidase on postoperative edema and pain reduction were evaluated.Materials and MethodsThe study included 38 patients who underwent guided bone regeneration (GBR) surgery before implantation. Patients were randomly assigned to either the control group (n=20) or the test group (n=18). Hyaluronidase was injected into the GBR site of subjects in the test group. Postoperative edema was evaluated by measuring the distance between specific facial landmarks immediately after surgery (T1) and 2-4 days after surgery (T2). The degree of pain at T2 and at 10-14 days after surgery (T3) was assessed.ResultsIn the test group, the degree of swelling was lower than in the control group, however, only two measurements, from the tragus to the mouth corner and from the outer canthus to the mouth corner, showed statistically significant differences (P=0.012 and P=0.001, respectively). The anti-edema effect of hyaluronidase was more effective in the maxilla than in the mandible. In the maxilla, the percentage of facial swelling was significant for three measurements. However, in the mandible, the percentage of facial swelling was significant for only one measurement. Low levels of pain that were similar at T2 and T3 were reported in both groups.ConclusionThe results indicate the degree of swelling was lower in the test group and hyaluronidase appeared to be more effective in the maxilla. The degree of pain reduction was similar between groups. Further in vivo and randomized controlled trials with larger sample sizes are warranted.

Starch based hydrogel NPs loaded by anthocyanins might treat glycogen storage at cardiomyopathy in animal fibrotic model

Many reports have been published recently confirmed the limitation of cargo molecules delivered into the heart. This failure is mostly associated with lymphatic or vascular channels washing or to the immune system recognition. Delivery of anthocyanins by encapsulation may augment it retention in the heart at early time points as the capsules are too large to wash out by lymphatic or venous channels and the physical structure of the capsule may shield the anthocyanins from immunoglobulins and cellular components of the immune system. In the current study, the cardiac dysfunction was induced by using carbon tetrachloride and then animal were treated orally by using anthocyanins incorporated into hydrogel NPs twice time /week for 4 weeks. The results showed anthocyanin loaded hydrogel NPs has ability to re-maintain the glycogen content in the liver and heart tissues of fibrotic group (13 ± 1.4 and 5 ± 0.7 μmol glucose/g tissue). Additionally, MDA and hydroxyproline were significantly reduced. PAS stain showed depletion of glycogen granules from heart tissue. It is concluded that starch based hydrogel loaded by anthocyanins can improve histological cardiac functions after their injury .

Ultrasound lymphatic imaging for the diagnosis of metastatic central lymph nodes in papillary thyroid cancer.

Up to 40% of papillary thyroid cancer (PTC) patients have lymph node metastasis, a condition that implies persistent, recurrent, or progressive disease. However, the American Joint Committee on Cancer Manual states that there is no reliable examination for adequate lymph node staging. Therefore, our aim is to develop a lymphatic imaging technique using ultrasonography to address this challenge. We consecutively enrolled PTC patients who underwent ultrasound (US) lymphatic imaging via the peritumoral injection of contrast media. Identification of the sentinel lymph nodes and the targeted sentinel lymph nodes was separately based on the lymphatic drainage pathway and the enhancement patterns. Every identified targeted node was assigned a score, according to the features on conventional US and enhancement patterns, and was referred for ultrasound-guided fine-needle aspiration. Cytological and histopathologic results represented the statuses of the targeted lymph nodes and overall central lymph nodes, respectively, which were applied to evaluate the diagnostic performance of US lymphatic imaging. In total, 100 PTC patients were included. On the basis of the cytological results, the sensitivity (97.1%, 95% confidence interval [CI]: 84.7-99.9%) of detecting positive targeted nodes by US lymphatic imaging significantly increased by 45.5% at a threshold of 4 or higher (p = 0.0001), without loss of specificity (p = 1.0000). The surgical results showed that the metastatic degree was positively correlated with an increase in the score (τ: 0.671, p < 0.001). Ultrasound lymphatic imaging has a high diagnostic performance, and its corresponding scoring system facilitates grading of the nodal burden in the central compartment. • Ultrasound neck lymphatic imaging is an effective contrast-enhanced ultrasound (CEUS) technique (applied after the peritumoral injection of contrast media) for identifying sentinel lymph nodes in the central compartment by tracing the imaged afferent lymphatic vessel. • Lack of enhancement or perfusion defects is the typical enhancement pattern for recognizing the involved central lymph nodes. • Ultrasound lymphatic imaging for identification of positive central lymph nodes before surgery may effectively avoid complications associated with the surgical sentinel node procedure.

Peritumoral lymph nodes in pancreatic cancer revisited; is it truly equivalent to lymph node metastasis?

Lymph node (LN) metastasis is a well-known poor prognostic factor of pancreatic cancer. LN metastasis, through direct invasion of tumor cell to peritumoral lymph nodes (PTLN), is treated as the same as those which spread through lymphatic channels. This study aimed to evaluate the impact of PTLN invasion on the oncologic outcome of pancreatic cancer. Five hundred and six patients who underwent operation for pancreatic ductal adenocarcinoma from 2012 to 2018 were reviewed. PTLN invasion was defined as direct invasion of tumor cells in contact with main tumor. Among the 506 patients, 112 patients (22.1%) had PTLN invasion. PTLN invasion group (PTLNI) showed better disease-free survival than regional LN metastasis group (RLNM) and combined LN metastasis group (CLNM) (PTLNI 21 vs RLNM 11 vs CLNM 12months, P=.003). There was no significant difference between N0 and PTLNI (PTLNI 21 vs N0 23months, P=.999). In multivariate analysis, conventional LN metastasis was a significant factor compared to N0, but PTLN invasion was not (hazard ratio 0.786 [0.507-1.220], P=.283). Because PTLN invasion does not adversely affect survival in the same way as LN metastasis does, pancreatic cancer-may be overstaged if PTLN invasion were dealt in the same manner as a metastatic LN. Therefore, PTLN invasion should be disregarded from current nodal staging system.

A Case-control Analysis of the Knight's Move Technique in a Chicken Wing Microsurgery Model: Video Article.

A Case-control Analysis of the Knight's Move Technique in a Chicken Wing Microsurgery Model: Video Article.

The Potential of Artificial Intelligence to Detect Lymphovascular Invasion in Testicular Cancer.

Simple SummaryTesticular cancer predominantly affects young adult men and is the most common cancer affecting this demographic. An important prognostic factor for early-stage disease is the presence of tumours within blood vessels or lymphatic channels, which is termed lymphovascular invasion. This is identified by careful microscopic examination of the tumour after orchidectomy, which is frequently challenging and time-consuming. We trained a proof-of-concept deep learning artificial intelligence algorithm to automatically identify areas suspicious for lymphovascular invasion in digital whole slide images from testicular tumours. Our study demonstrates that automated detection of areas suspicious for lymphovascular invasion by artificial intelligence algorithms is feasible and may prove useful in the context of a decision support tool.Testicular cancer is the most common cancer in men aged from 15 to 34 years. Lymphovascular invasion refers to the presence of tumours within endothelial-lined lymphatic or vascular channels, and has been shown to have prognostic significance in testicular germ cell tumours. In non-seminomatous tumours, lymphovascular invasion is the most powerful prognostic factor for stage 1 disease. For the pathologist, searching multiple slides for lymphovascular invasion can be highly time-consuming. The aim of this retrospective study was to develop and assess an artificial intelligence algorithm that can identify areas suspicious for lymphovascular invasion in histological digital whole slide images. Areas of possible lymphovascular invasion were annotated in a total of 184 whole slide images of haematoxylin and eosin (H&E) stained tissue from 19 patients with testicular germ cell tumours, including a mixture of seminoma and non-seminomatous cases. Following consensus review by specialist uropathologists, we trained a deep learning classifier for automatic segmentation of areas suspicious for lymphovascular invasion. The classifier identified 34 areas within a validation set of 118 whole slide images from 10 patients, each of which was reviewed by three expert pathologists to form a majority consensus. The precision was 0.68 for areas which were considered to be appropriate to flag, and 0.56 for areas considered to be definite lymphovascular invasion. An artificial intelligence tool which highlights areas of possible lymphovascular invasion to reporting pathologists, who then make a final judgement on its presence or absence, has been demonstrated as feasible in this proof-of-concept study. Further development is required before clinical deployment.

Evidence for disseminated tumor cells in lymphatic vessels afferent to sentinel lymph nodes in patients diagnosed with cervical cancer

BackgroundIn patients diagnosed with cervical cancer, the purpose of lymphadenectomy is the removal of lymph nodes for diagnosis and potential treatment of metastasized tumor cells. It is unclear if afferent lymphatic vessels harbor tumor cells and, thus, may pose additional risk for recurrence or progression if not removed.AimIn this feasibility study, we analyzed the lymphatic vessels afferent to sentinel lymph node (SLN) using a highly sensitive and specific molecular marker for cervical cancer cells.Methods and ResultsTwenty patients diagnosed with cervical cancer of FIGO stage IA1 to IIB2 underwent laparoscopic SLN removal. Labeling was done using patent blue and the afferent lymphatic vessels were harvested from the parametric tissue and frozen at −80°C. HPV DNA type was evaluated in the primary tumor. Lymphatic vessels afferent to the sentinel lymph nodes were analyzed for the presence of viral oncogene transcripts of the respective HPV type. In one of 18 patients, all with tumor stage ≤IBI and pN0 by conventional histopathology, HPV mRNA could be detected in two of four lymphatic vessels, whereas at least one of the lymphatic vessel biopsies of both patients with tumors ˃4 cm and pN1 status was HPV mRNA positive. No clinical correlation with recurrence after a median follow‐up of 9 years was noticed.ConclusionHPV mRNA indicative of disseminated tumor cells could be detected in lymphatic vessels. The relevance of harvesting lymphatic vessels afferent to SLN in order to increase oncologic safety will have to be investigated in a future prospective study.

Dendritic cell entry to lymphatic capillaries is orchestrated by CD44 and the hyaluronan glycocalyx

DCs play a vital role in immunity by conveying antigens from peripheral tissues to draining lymph nodes, through afferent lymphatic vessels. Critical to the process is initial docking to the lymphatic endothelial receptor LYVE-1 via its ligand hyaluronan on the DC surface. How this relatively weak binding polymer is configured for specific adhesion to LYVE-1, however, is unknown. Here, we show that hyaluronan is anchored and spatially organized into a 400-500 nm dense glycocalyx by the leukocyte receptor CD44. Using gene knockout and by modulating CD44-hyaluronan interactions with monoclonal antibodies in vitro and in a mouse model of oxazolone-induced skin inflammation, we demonstrate that CD44 is required for DC adhesion and transmigration across lymphatic endothelium. In addition, we present evidence that CD44 can dynamically control the density of the hyaluronan glycocalyx, regulating the efficiency of DC trafficking to lymph nodes. Our findings define a previously unrecognized role for CD44 in lymphatic trafficking and highlight the importance of the CD44:HA:LYVE-1 axis in its regulation.

Huge Vulval Elephantiasis of Filarial Origin: Diagnosis by Exclusion

Background: Elephantiasis is a rare disorder involving lymphatic channels of the affected part of the body. It is characterized by huge enlargement of the particular body part and likely to affect limbs, scrotum, and trunk. Genital elephantiasis, also known as esthiomene, is a rare dramatic end result of lymphatic obstruction. Although mainly associated with filariasis and sexually transmitted diseases such as lymphogranuloma venereum and donovanosis, it could also be an uncommon complication of tubercular lymphadenitis. Case: A 40-year-old multiparous woman presented with progressively increasing vulval swelling over a period of 3–4 years. The swelling was soft and huge. She was managed successfully by surgical excision with vulvoplasty. Other possible differential diagnoses were excluded, and ancillary tests were performed to reach a conclusive diagnosis of vulval elephantiasis on histopathology. Conclusion: Vulval elephantiasis due to filariasis is rare and diagnosis on histopathology is more often by exclusion.

Visualization of brain microvasculature and blood flow in vivo: Feasibility study using confocal laser endomicroscopy.

Qualitative and quantitative analyses of blood flow in normal and pathologic brain and spinal cord microvasculature were performed using confocal laser endomicroscopy (CLE). Blood flow in cortical, dural, and spinal cord microvasculature was assessed in vivo in swine. We assessed microvasculature under normal conditions and after vessel occlusion, brain injury due to cold or surgical trauma, and cardiac arrest. Tumor-associated microvasculature was assessed in vivo and ex vivo in 20 patients with gliomas. We observed erythrocyte flow in vessels 5-500µm in diameter. Thrombosis, flow arrest and redistribution, flow velocity changes, agglutination, and cells rolling were assessed in normal and injured brain tissue. Microvasculature in in vivo CLE images of gliomas was classified as normal in 68% and abnormal in 32% of vessels on the basis of morphological appearance. Dural lymphatic channels were discriminated from blood vessels. Microvasculature CLE imaging was possible for up to 30minutes after a 1mg/kg intravenous dose of fluorescein. CLE imaging allows assessment of cerebral and tumor microvasculature and blood flow alterations with subcellular resolution intraoperative imaging demonstrating precise details of real-time cell movements. Research and clinical scenarios may benefit from this novel intraoperative in vivo microscopic fluorescence imaging modality.

Changes of lymphatic flow caused by core needle biopsy of axillary sentinel lymph node in a rabbit model.

Core needle biopsy (CNB) plays an important role in the preoperative axillary lymph node (ALN) assessment in breast cancer (BC) patients with the development of treatment, but little is known about the axillary lymph flow after CNB of ALNs. This study aimed to investigate the changes of lymphatic flow after CNB of sentinel lymph node (SLN) in a rabbit model. The axillary SLN was biopsied in a rabbit model, and the changes of sentinel lymph flow were observed by methylthioninium chloride imaging at 1 and 12 days after the biopsy. Furthermore, the afferent lymphatic vessel was ligated and imaged once every 3 days to assess the changes of lymphatic flow. The SLN biopsied was characterized by disorganized medullary sinus containing erythrocytes, whereas clean medullary sinus containing a normal population of circulating lymphoid cells was observed in the contralateral normal SLN. At 1 day after biopsy, the sentinel lymphatic drainage was blocked. At 12 days after biopsy, the sentinel lymphatic flow was reconstructed or repaired. Ligation of afferent lymphatic vessel further confirmed the reconstruction of lymphatic flow. The sentinel lymphatic flow changes after CNB in a rabbit model, but it can be reconstructed or repaired.

NON-CONTRAST MR LYMPHOGRAPHY OF RARE LYMPHATIC ABNORMALITIES

Detailed imaging of the lymphatic system often requires direct injection of contrast into lymph nodes which can be technically challenging, time consuming, and produce painful stimuli. We sought to describe the use of non-contrast MR lymphography (NCMRL) for normal controls and patients with a variety of rare disorders associated with lymphatic pathologies. Two control subjects and five affected patients (decompensated Fontan circulation, central conducting lymphatic abnormality, familial lymphedema and two with Gorham-Stout disease) were studied. NCMRL images were segmented in a semiautomated fashion and the major lymphatic channels and thoracic duct (TD) highlighted for identification. Adequate imaging was available for both controls and 4/5 affected patients; the youngest patient could not be imaged given patient motion. For the two controls, the TD was seen in the expected anatomic location. For the decompensated Fontan patient, there were numerous tortuous lymphatic channels, predominantly in the upper chest and neck. For the familial lymphedema patient, a TD was not identified; instead, peripheral lymphatic collaterals near the lateral chest walls. For the first Gorham- Stout patient, the TD was enlarged with large intrathoracic lymph collections. For the second Gorham-Stout patient, there were bilateral TD with lymph collections in vertebral bodies. Using NCMRL, we were able to image normal and abnormal lymphatic systems. An important learning point is the potential need for sedation for younger patients due to long image acquisition times and fine resolution of the structures of interest.