Computed Tomography Lymphography Research Articles

The Use of Sentinel Lymph Node Mapping for Canine Mast Cell Tumors.

Cancer is the leading cause of death in companion animals. The evaluation of locoregional lymph nodes, known as lymph node mapping, is a critical process in assessing the stage of various solid tumors, such as mast cell tumors (MCTs), anal gland anal sac adenocarcinoma, melanoma, and mammary gland adenocarcinoma. MCTs are among the most prevalent skin malignancies in dogs. Staging is used to describe the extent of neoplastic disease, provide a framework for rational treatment planning, and evaluate treatment results. The aim of this review is to present the current knowledge on sentinel lymph node (SLN) mapping in canine MCTs, its influence on treatment decisions and prognosis, as well as the advantages and limitations of different SLN techniques currently available in veterinary oncology. A search methodology was adopted using the PubMed, Scopus, and Google Scholar databases. Critical analyses of up-to-date research have shown that lymphoscintigraphy can achieve a lymph node detection rate of between 91 and 100%. This method is becoming increasingly recognized as the gold standard in both human and veterinary medicine. In addition, initial studies on a limited number of animals have shown that computed tomographic lymphography (CTL) is highly effective in the SLN mapping of MCTs, with detection rates between 90 and 100%. The first study on contrast-enhanced ultrasound (CEUS) also revealed that this advanced technique has up to a 95% detection rate in canine MCTs. These methods provide non-ionizing alternatives with high detection capabilities. Furthermore, combining computed tomography and near-infrared fluorescence (NIR/NIR-LND) lymphography is promising as each technique identifies different SLNs. Indirect lymphography with Lipiodol or Iohexol is technically feasible and may be also used to effectively detect SLNs. The integration of these mapping techniques into routine MCT staging is essential for enhancing the precision of MCT staging and potentially improving therapeutic outcomes. However, further clinical trials involving a larger number of animals are necessary to refine these procedures and fully evaluate the clinical benefits of each technique.

CT features of cutaneous and subcutaneous canine mast cell tumors and utility of conventional and indirect lymphography to detect clinically unknown mast cell tumors and to map the sentinel lymph nodes.

Computed tomography is frequently used to stage canine mast cell tumors (MCTs). The aims of this prospective, observational study were to describe the CT features of MCTs, to evaluate the performance of CT in detecting additional or incidental MCTs, to distinguish between cutaneous (cMCT) or subcutaneous (scMCT) MCTs, and to identify one or multiple sentinel lymph nodes (SLNs) by indirect CT lymphography (ICTL). Seventy-two dogs affected by 111 MCTs were included. The recorded parameters were: shape, size, attenuation (Hounsfield units [HU]), location (cutaneous or subcutaneous), and presence of fat stranding. The SLNs were compared with the regional lymph nodes and supplementary MCTs were registered. Mast cell tumors mostly appeared with well-defined margins (89%), round/oval shape (71%), homogeneous enhancement (90%) with a mean postcontrast density of 62.0±23.4 HU and associated with fat stranding (43%). Cutaneous mast cell tumors were more frequently round (P=.003), whereas scMCTs were oval (P=.011) with a larger mean maximal diameter (2.91±1.57cm vs 1.46±1.28cm, P=.002) and more feeding vessels (77% vs 39% P=.044). Compared with histopathology, CT accuracy in differentiating cMCTs and sMCTs was 57%, with an interobserver agreement of 88% (three reviewers). Indirect CT lymphography showed the SLN in 82 of 85 (97%) cases, 32% of them not corresponding to the regional node. CT showed additional or incidental MCTs in 23 of 72 (32%) dogs. In conclusion, the common CT appearance of canine cMCTs and scMCTs is reported with some statistical differences between the two categories. CT is useful in identifying clinically undetected MCTs and SLNs, although it shows low accuracy in distinguishing between cMCT and scMCT.

Prognostic study of sentinel lymph node biopsy in early-stage oral squamous cell carcinoma with computed tomography lymphography

PurposeOccult metastasis is a prognostic factor for early-stage oral squamous cell carcinoma (OSCC). Sentinel lymph node (SLN) biopsy (SLNB) is a promising method to detect such metastases. The present study aimed to evaluate the diagnostic reliability of SLNB with computed tomography lymphography (CTL) for early-stage OSCC and to clarify patient outcomes after SLNB. MethodsThe medical records of 42 patients with T1 or T2 cN0 OSCC who had undergone CTL the day before surgery were retrospectively collected and statistically analyzed. ResultsSLNs were identified on CTL in 41 of 42 OSCC patients (97.6 %). Micrometastases were detected in 10 of 41 cases (24.4 %) and 11 of 65 SLNs (16.9 %) by intraoperative pathological diagnosis. Three cases showed occult metastasis within a year after the primary operation. Specificity and negative predictive value were 76.9 % and 90.3 %, respectively. The cumulative 5-year regional recurrence-free rate was 89.7 % in 31 SLNB-negative patients. Five-year overall and disease-free survival rates were 86.9 % and 70.1 %, respectively, in the 41 cases with identified SLNs. ConclusionCTL offers acceptable results and appears likely to be effective in treating early-stage OSCC patients with low-invasive surgery. Further investigation is necessary to compare radioisotope-based methods.

Sentinel lypmh node biopsy in early breast cancer: preliminary results of the combined technique of CT lymphography and blue-dye

Aim: The aim of this study was to evaluate the efficacy of CT lymphography in sentinel lymph node biopsy for early stage breast cancer and to investigate its contribution to the conventional blue-dye method.
 Material and Method: A total of 47 patients with early stage breast cancer underwent preoperative CT lymphography for lymph node mapping before sentinel lymph node biopsy with blue-dye method. The lymph nodes identified by CT lymphography and/or blue-dye method were examined for metastatic involvement. The sentinel lymph node detection rates of CT lymphography and blue-dye method were compared using t-tests.
 Results: The sentinel lymph node detection rate with blue-dye method (87.2%) was significantly higher than with CT lymphography (66.0%) (P=0.027). However, the combined method (blue-dye method and/or CT lymphography) increased the detection rate (95.7%) (P=0.267). Benign sentinel lymph nodes were detected more often with CT lymphography (P=0.366), while metastatic sentinel lymph nodes were detected more often with blue-dye method (P=1,000). Upper outer quadrant tumors were detected less successfully with CT lymphography and more successfully with blue-dye method (P=0.220 and P=0.674, respectively). The success rate of CT lymphography in younger patients (less than 50 years old) was higher compared to older patients (P=0.001).
 Conclusion: CT lymphography was found to be insufficient as a standalone method for sentinel lymph node biopsy. However, it could be used as a complementary method to blue-dye method to increase the success of sentinel lymph node detection.

Three-dimensional visual technique based on CT lymphography data combined with methylene blue in endoscopic sentinel lymph node biopsy for breast cancer

BackgroundThe combined application of blue dye and radioisotopes is currently the primary mapping technique used for sentinel lymph node biopsy (SLNB) in breast cancer patients. However, radiocolloid techniques have not been widely adopted, especially in developing countries, given the strict restrictions on radioactive materials. Consequently, we carried out a retrospective study to evaluate the feasibility and accuracy of three-dimensional visualization technique (3DVT) based on computed tomography-lymphography (CT-LG) in endoscopic sentinel lymph node biopsy (ESLNB) for breast cancer.MethodsFrom September 2018 to June 2020, 389 patients who underwent surgical treatment of breast cancer in our department were included in this study. The CT-LG data of these patients were reconstructed into digital 3D models and imported into Smart Vision Works V1.0 to locate the sentinel lymph node (SLN) and for visual simulation surgery. ESLNB and endoscopic axillary lymph node dissection were carried out based on this new technique; the accuracy and clinical value of 3DVT in ESLNB were analyzed.ResultsThe reconstructed 3D models clearly displayed all the structures of breast and axilla, which favors the intraoperative detection of SLNs. The identification rate of biopsied SLNs was 100% (389/389). The accuracy, sensitivity, and false-negative rate were 93.83% (365/389), 93.43% (128/137), and 6.57% (9/137), respectively. Upper limb lymphedema occurred in one patient 3 months after surgery during the 12-month follow-up period.ConclusionsOur 3DVT based on CT-LG data combined with methylene blue in ESLNB ensures a high identification rate of SLNs with low false-negative rates. It, therefore, has the potential to serve as a new method for SLN biopsy in breast cancer cases.

CT Lymphography Using Lipiodol® for Sentinel Lymph Node Biopsy in Early-Stage Oral Cancer.

This study evaluated sentinel lymph node (SLN) identification with CT lymphography (CTL) following peritumoral administration of Lipiodol® relative to conventional 99mTc-nanocolloid lymphoscintigraphy (including SPECT/CT) in 10 early-stage oral cancer patients undergoing SLN biopsy. Patients first underwent early dynamic and static scintigraphy after peritumoral administration of 99mTc-nanocolloid. Subsequently, Lipiodol® was administered at the same injection sites, followed by fluoroscopy and CT acquisition. Finally, late scintigraphy and SPECT/CT were conducted, enabling the fusion of late CTL and SPECT imaging. The next day, designated SLNs were harvested, radiographically examined for Lipiodol® uptake and histopathologically assessed. Corresponding images of CT, 99mTc-nanocolloid lymphoscintigraphy and SPECT/late CTL fusion were evaluated. 99mTc-nanocolloid lymphoscintigraphy identified 21 SLNs, of which 7 were identified with CTL (33%). CTL identified no additional SLNs and failed to identify any SLNs in four patients (40%). Out of six histopathologically positive SLNs, two were identified by CTL (33%). Radiographic examination confirmed Lipiodol® uptake in seven harvested SLNs (24%), of which five were depicted by CTL. CTL using Lipiodol® reached a sensitivity of 50% and a negative predictive value (NPV) of 75% (median follow-up: 12.3 months). These results suggest that CTL using Lipiodol® is not a reliable technique for SLN mapping in early-stage oral cancer.

Imaging features of sentinel lymph node mapped by multidetector-row computed tomography lymphography in predicting axillary lymph node metastasis

IntroductionAccurately assessing axillary lymph node (ALN) status in breast cancer is vital for clinical decision making and prognosis. The purpose of this study was to evaluate the predictive value of sentinel lymph node (SLN) mapped by multidetector-row computed tomography lymphography (MDCT-LG) for ALN metastasis in breast cancer patients.Methods112 patients with breast cancer who underwent preoperative MDCT-LG examination were included in the study. Long-axis diameter, short-axis diameter, ratio of long-/short-axis and cortical thickness were measured. Logistic regression analysis was performed to evaluate independent predictors associated with ALN metastasis. The prediction of ALN metastasis was determined with related variables of SLN using receiver operating characteristic (ROC) curve analysis.ResultsAmong the 112 cases, 35 (30.8%) cases had ALN metastasis. The cortical thickness in metastatic ALN group was significantly thicker than that in non-metastatic ALN group (4.0 ± 1.2 mm vs. 2.4 ± 0.7 mm, P < 0.001). Multi-logistic regression analysis indicated that cortical thickness of > 3.3 mm (OR 24.53, 95% CI 6.58–91.48, P < 0.001) had higher risk for ALN metastasis. The best sensitivity, specificity, negative predictive value(NPV) and AUC of MDCT-LG for ALN metastasis prediction based on the single variable of cortical thickness were 76.2%, 88.5%, 90.2% and 0.872 (95% CI 0.773–0.939, P < 0.001), respectively.ConclusionALN status can be predicted using the imaging features of SLN which was mapped on MDCT-LG in breast cancer patients. Besides, it may be helpful to select true negative lymph nodes in patients with early breast cancer, and SLN biopsy can be avoided in clinically and radiographically negative axilla.

Evaluating the Feasibility and Efficacy of a Dual-Modality Nanoparticle Contrast Agent (Nanotrast-CF800) for Image-Guided Sentinel Lymph Node Mapping in the Oral Cavity of Healthy Dogs.

A combination of pre and intraoperative sentinel lymph node (SLN) mapping techniques have been suggested to optimize SLN detection. A novel liposomal nanoparticle, Nanotrast-CF800 (CF800), utilizes computed tomography lymphography (CTL) and near infrared fluorescence imaging (NIRF) for image-guided surgery and SLN mapping. This novel tracer agent has not been evaluated in companion animals. The objective of this study was to evaluate the feasibility and efficacy of CF800 for SLN mapping in the oral cavity of healthy dogs and to report any local adverse effects. Six healthy adult purpose-bred research dogs randomly received either 1 mL (group 1) or 2 mL (group 2) of CF800 injected into the submucosa at the level of the right canine maxillary tooth. CTL and percutaneous NIRF were performed at 1, 3, and 10 min, then 1, 2, 4, 7, and 10 days post-injection (p.i). Overall, both CTL and NIRF identified SLNs in all dogs. The overall peak mean contrast enhancement of the SLNs was 73.98 HU (range 63.45–86.27 HU) at 2 days p.i. Peak fluorescence of the SLN occurred at 1 day p.i. The agent was retained within the SLN for at least 7 days for CTL and 4 days for percutaneous NIRF. No adverse effects were observed. Local administration of CF800 was simple and feasible for the detection of SLNs using CTL+NIRF in the head and neck of healthy dogs and was not associated with significant local adverse events.

Using Computed Tomography Lymphography for Mapping of Sentinel Lymph Nodes in Patients with Breast Cancer.

Objectives:In breast cancer surgery, the combined use of the dye method and radioisotope (RI) method is recommended for identifying sentinel lymph nodes. However, the RI method is difficult to license, expensive, and difficult to introduce. Thus, we introduced computed tomography lymphography (CTLG) and investigated the characteristics and usefulness of CTLG.Material and Methods:Among breast cancer patients who underwent surgery during a 6-year period from January 2013 to December 2018, CTLG was performed on 141 patients with clinically negative lymph node metastasis. These cases were then retrospectively investigated. The number and location of lymph vessel, true sentinel lymph nodes, and the positional relationships with surrounding muscles and blood vessels were confirmed from the constructed 3D images. The actual surgeries were then performed using a dye method with indigo carmine based on images obtained using CTLG.Results:CTLG was able to identify lymph vessels and true sentinel lymph nodes in 131 of the 141 cases (92.91%). There were 97 patients in whom the first true sentinel lymph node reached from the breast was one node, 30 with two nodes, and 4 with three nodes. Moreover, there were three cases in which sentinel lymph nodes were present at Level II. During surgery, sentinel lymph nodes were identified in 131 patients (92.91%) using dye.Conclusion:CTLG has a high identification rate in sentinel lymph nodes, and it is considered a convenient and useful examination method because a lot of information, such as the number and position of sentinel lymph nodes, can be obtained.

Diversity of lymphatic flow in patients with lung cancer revealed by computed tomography lymphography

This study was conducted to verify the optimal extent of lymph node dissection or sampling during lung cancer surgery based on the sentinel node (SN) map created by computed tomography (CT) lymphography. From April 2010 to January 2015, patients with clinical stage I non-small-cell lung cancer, who were candidates for lobectomy or segmentectomy with standard hilar and mediastinal lymph node dissection, and in whom bronchus reached the tumour, were enrolled. An ultrathin bronchoscope was inserted to the target bronchus under the guidance of virtual bronchoscopic navigation images. CT images of the chest were obtained 30 s after 2.5 ml of iopamidol was injected. SNs were identified when the maximum CT attenuation value of the lymph nodes on postcontrast CT images increased by 30 Hounsfield units or more compared with the precontrast images. Patients underwent lobectomy with standard lymph node dissection. SNs were identified in 36 (87.8%) of the 41 patients. The average number of SNs was 1.6 (range, 1-4). There was 1 false negative case; therefore, the accuracy of SN identification was 97.2% (35/36). In 5 (13.9%) of 36 patients, SNs were outside the lobe-specific lymph node station range (#11i from right S1, #7 from right S1, #4R from right S8, #12u from right S8, #7 and #12l from left S1 + 2). CT lymphography demonstrated the diversity of lymphatic spreading patterns and there were cases in which lymph flows are found outside the lymph node dissection range.

Thoracoscopic detection of thoracic ducts after ultrasound-guided intrahepatic injection of indocyanine green detected by near-infrared fluorescence and methylene blue in dogs.

To describe and compare onset and intensity of thoracic duct (TD) coloration in healthy dogs after intrahepatic injection of either indocyanine green (ICG) visualized by intraoperative near-infrared fluorescence lymphography (NIRFL) or direct thoracoscopic visualization of methylene blue dye (MB). Prospective study. Healthy adult Beagle dogs (n=5). All dogs had biochemical panels and complete blood counts preoperatively. Computed tomography lymphography (CTL) was performed prior to a standard 3-port thoracoscopic approach. A mixture of MB and ICG was injected by ultrasound-guided percutaneous injection into right or left-sided hepatic lobes. Data collected included dose of contrast agent (MB vs. ICG), injection site, timing, and quality of operative TD identification. Potential hepatic injury was assessed by repeat laboratory evaluation and abdominal ultrasound 14 days postoperatively. Preoperative CTL provided a diagnostic study in 5/5 dogs. After intrahepatic injection of combined dyes, NIRFL allowed visualization of TDs in 5/5 dogs, but MB did not result in visible TD coloration in any dog. Intrahepatic injection of ICG achieved successful NIRFL in a median time of 6minutes and persisted for the 20 minute observation period in all five dogs. All dogs recovered without complication and were subsequently adopted. NIRFL of the TD can be achieved with intraoperative hepatic injection of ICG. Intrahepatic injection of MB did not result in visible TD coloration. Hepatic intra-parenchymal injection is a reliable alternative portal into the TD system for intraoperative visualization of TD anatomy using ICG in dogs.

Determining agreement between preoperative computed tomography lymphography and indocyanine green near infrared fluorescence intraoperative imaging for sentinel lymph node mapping in dogs with oral tumours.

Determining agreement between preoperative computed tomography lymphography and indocyanine green near infrared fluorescence intraoperative imaging for sentinel lymph node mapping in dogs with oral tumours.

Sentinel lymph node biopsy in breast cancer guided by CT lymphography; History, evolution and current applications.

Sentinel lymph node biopsy (SLNB) has efficiently replaced axillary lymph node dissection (ALND) in axillary staging in node-negative breast cancer patients. Dual sentinel lymph node (SLN) localization using radioisotopes and blue dye is the standard technique for SLN mapping. Yet, nuclear medicine facilities are not widely available worldwide. In Japan, Computed tomography lymphography (CTLG) is presented as an SLN mapping technique which was first suggested in 2003 by Suga etal. Multiple subsequent studies confirmed the efficacy of CTLG in SLN mapping in breast cancer. Further applications of the technique followed; such as prediction of SLN metastasis using CTLG, the use of CTLG guided SLN biopsy after neoadjuvant therapy, video-assisted CTLG guided SLN biopsy, the use of real-time virtual sonography with 3-D CTLG, and preoperative localization of the CTLG mapped SLN using either real-time virtual sonography (RVS) guided Indocyanine green (ICG) injection or its marking using liquid charcoal and silver wire and the use of SPIO enhanced magnetic resonance imaging (MRI) for prediction of metastasis in SLNs detected by CTLG. This efficacy and variable applications open the door for conducting wide-scale randomized controlled trials to suggest using CTLG as an efficient alternative for the use of radioisotopes in SLN mapping in breast cancer patients, especially in low and middle-income countries.

Application of preoperative computed tomographic lymphography for precise sentinel lymph node biopsy in breast cancer patients

BackgroundIn light of the extensive application of sentinel lymph node biopsy (SLNB) in clinically node-negative breast cancer patients and the recently investigated failure of SLNB after lumpectomy, it has become important to explore methods for preoperative mapping of sentinel lymph nodes (SLNs) and their lymphatics to direct precise SLNB and improve the identification rate of SLNs.MethodsTwenty-seven patients with suspected breast cancer based on the results of the clinical examination and imaging were enrolled in the study. Computed tomographic lymphography (CTLG) followed by CT three-dimensional reconstruction was performed to determine the localization of SLNs and lymphatics on the body surface preoperatively. Intraoperatively combined staining with methylene blue and indocyanine green was used to evaluate the accuracy and feasibility of CTLG.ResultsSLNs and lymphatics from the breast were identified using CTLG in all patients, and preoperative SLNs and lymphatics localization on the body surface showed a significant role in the selection of operative incision and injection points. The accuracy rate of SLN and lymphatic detection by CTLG was 92.6% compared with intraoperatively combined staining. Moreover, preoperative CTLG performed well in SLN number detection, and the accuracy rate was 95.2%.ConclusionWe evaluate the procedure and application of preoperative CTLG in the superficial localization of SLNs and lymphatics, which may lead to a decreased incidence of cutting off the lymphatics of SLNs and consequently more rapid and accurate SLN detection. This method promotes personalized SLN mapping, providing detailed information about the number and anatomical location of SLNs and lymphatics for adequate surgical planning for breast cancer patients.

Canine idiopathic chylothorax: Anatomic characterization of the pre- and postoperative thoracic duct using computed tomography lymphography.

Surgical treatment has improved the prognosis of canine idiopathic chylothorax, although a recurrence of the disease occurs occasionally after the procedure. An improved understanding of possible causes for this recurrence would be helpful for prognosis and treatment planning in affected patients. In this retrospective case series study, we described the detailed pre- and postoperative computed tomographic lymphography (CTLG) imaging characteristics for a group of dogs with surgically confirmed idiopathic chylothorax. Preoperative CTLG was performed in 12 of 14 dogs diagnosed with idiopathic chylothorax. Thoracic ducts were present on the right side in 10 dogs, left side in one dog, and bilaterally in one dog. All the 14 dogs received a combination therapy of pericardiectomy and thoracic duct ligation (TDL) by video-assisted thoracoscopic surgery. One week after surgery, a postoperative CTLG was performed, and the thoracic ducts were apparent in seven of 14 dogs. Three dogs had an unchanged course of the thoracic duct, which could have resulted from a missed duct. Four dogs were identified as having a bypass formation: the oblique duct originated at the ligation site and connected to the duct on the other side. Our findings indicated that one of the possible causes for postoperative recurrence of chylothorax in dogs could be "invisible or sleeping" fine ducts that are collapsed and not visible in preoperative CTLG scans. After TDL causes a change in the pressure of lymphatic flow, these fine thoracic ducts may become apparent using postoperative CTLG.

Determining agreement between preoperative computed tomography lymphography and indocyanine green near infrared fluorescence intraoperative imaging for sentinel lymph node mapping in dogs with oral tumours.

Lymphatic drainage from the head and neck is variable with significant crossover, therefore sentinel lymph node (SLN) mapping can help ensure the appropriate lymph node(s) are sampled. To improve sensitivity, SLN mapping utilizing multiple modalities and a combination of preoperative computed tomography lymphography (CTL) and intraoperative near infrared fluorescence imaging (NIRF) with indocyanine green (ICG) +/- methylene blue (MB) dye has been suggested. The aim of this study was to describe a method for intraoperative ICG lymphography and determine agreement for SLN detection using preoperative CTL and intraoperative ICG NIRF + MB lymphography (IOL) in dogs with oral tumours. Fourteen client-owned dogs were included. All dogs had preoperative CTL with iodinated contrast and intraoperative IOL with an exoscope. Lymph nodes with CTL contrast-enhancement, blue staining or fluorescence were considered sentinel. The overall SLN identification rate was 100% when CTL and IOL were combined. A total of 57 SLNs were identified. Indocyanine green NIRF identified a greater proportion of SLNs (91%; 52/57) compared with MB (50.8%; 29/57) and CTL (42.1%; 24/57). Eighteen SLNs were identified by all three modalities with a fair level of agreement using Fleiss kappa. These findings suggest a combination of preoperative CTL with intraoperative SLN mapping techniques may greatly improve the ability to accurately detect the SLN in dogs with oral tumours.

MR lymphography with superparamagnetic iron oxide for sentinel lymph node mapping of N0 early oral cancer: A pilot study.

The purpose of this pilot study was to evaluate the usefulness of magnetic resonance lymphography (MRL) with superparamagnetic iron oxide (SPIO) in sentinel lymph node (SLN) mapping of clinically N0 early oral cancer, and to conduct a comparative study of this MRL with CT lymphography (CTL). CTL and MRL were performed for SLN mapping before surgery for 20 patients with clinically N0 early oral cancer. The detection rate, number, and location of SLNs in CTL and MRL were evaluated. Furthermore, optimal scanning/imaging timing in MRL was examined. SLNs were detected by CTL in 18 (90%) patients, and the total and mean number of SLN were 35 and 1.8, respectively. All SLNs could be detected 2 min and 3.5-5 min after contrast medium injection. In all patients, SLNs were detected by MRL at 10 min after SPIO injection, and the total and mean number of SLN was 53 and 2.7, respectively. MRL at 30 min after the injection showed additional 18 secondary lymph nodes. MRL with SPIO is safe and useful imaging for the detection of SLNs in clinically N0 early oral cancer, and the optimal imaging timing is 10 min after SPIO injection.

New Developments in Imaging for Sentinel Lymph Node Biopsy in Early-Stage Oral Cavity Squamous Cell Carcinoma.

Simple SummaryIn early-stage (cT1-2N0) oral cancer, occult lymph node metastases are present in 20–30% of patients. Accordingly, accurate staging of the clinically negative cervical nodal basin is warranted in these patients. Sentinel lymph node biopsy has proven to reliably stage the clinically negative cervical nodal basin in early-stage oral cancer. However, due to the limited resolution of conventional sentinel lymph node imaging, occult lymph node metastasis may be missed in particular circumstances. Therefore, technical developments are necessary to bring the diagnostic accuracy of sentinel lymph node biopsy, in early-stage oral cancer, to a higher level. This review evaluates novel sentinel lymph node imaging techniques for early-stage oral cancer, such as MR lymphography, CT lymphography, PET lymphoscintigraphy and contrast-enhanced lymphosonography. Their reported diagnostic accuracy is described and their relative merits, disadvantages and potential applications are outlined.Sentinel lymph node biopsy (SLNB) is a diagnostic staging procedure that aims to identify the first draining lymph node(s) from the primary tumor, the sentinel lymph nodes (SLN), as their histopathological status reflects the histopathological status of the rest of the nodal basin. The routine SLNB procedure consists of peritumoral injections with a technetium-99m [99mTc]-labelled radiotracer followed by lymphoscintigraphy and SPECT-CT imaging. Based on these imaging results, the identified SLNs are marked for surgical extirpation and are subjected to histopathological assessment. The routine SLNB procedure has proven to reliably stage the clinically negative neck in early-stage oral squamous cell carcinoma (OSCC). However, an infamous limitation arises in situations where SLNs are located in close vicinity of the tracer injection site. In these cases, the hotspot of the injection site can hide adjacent SLNs and hamper the discrimination between tracer injection site and SLNs (shine-through phenomenon). Therefore, technical developments are needed to bring the diagnostic accuracy of SLNB for early-stage OSCC to a higher level. This review evaluates novel SLNB imaging techniques for early-stage OSCC: MR lymphography, CT lymphography, PET lymphoscintigraphy and contrast-enhanced lymphosonography. Furthermore, their reported diagnostic accuracy is described and their relative merits, disadvantages and potential applications are outlined.

Patients Radiation Risks from Computed Tomography Lymphography.

Objectives:This study aims to first measure patient doses during computed tomography (CT) chest, abdomen, and extremities procedures for evaluation lymphedema, and second to estimate the radiation dose-related risks during the procedures.Material and Methods:Radiation effective doses from CT lymphography procedures quantified using CT machines from different vendors. After the calibration of CT systems, the data collected for a total of 28 CT lymphography procedures. Effective and organ doses extrapolated using national radiological protection software based on Monte Carlo simulation.Results:The mean patient doses for chest and abdomen procedures in term of CTDIvol (mGy) and DLP (mGy.cm) are 10.0 ± 3 and 425 ± 222 and 24 ± 12 and 1118 ± 812 for CT 128 and CT 16 slice, respectively. The mean DLP (mGy.cm) for extremities was 320 ± 140 and 424 ± 212 for CT 128 and CT 16 slice, in that order.Conclusion:Patients’ dose showed significant differences due to variation in the scan length and clinical indication. Organs lay in the primary beam received high radiation doses especially in the chest region which increases the probability of radiation-induced cancer. The current patient’s doses are higher compared to the previous studies.

Sentinel lymph node mapping of clinically N0 early oral cancer: a diagnostic pitfall on CT lymphography.

The purpose of this study was to reevaluate preoperative computed tomography lymphography (CTL) and enhanced CT images during follow-up to clarify whether SLNs enhanced by CTL were identified accurately before primary surgery with sentinel lymph node biopsy (SLNB) for clinically N0 early oral cancer. Thirty two early oral cancer patients without cervical lymph node metastasis were enrolled in this study. To clarify whether SLNs enhanced by CTL were identified accurately before primary surgery with SLNB, we reevaluated preoperative CTL and enhanced CT images during follow-up in all patients. SLNs were detected by CTL in 31 of 32 patients (96.9%). During follow-up after primary surgery with SLNB, 4 of 27 patients without SLN metastasis had occult neck metastasis. Of the 4 patients, only 1 patient with cancer of floor of the mouth had overlooking of SLN, and the overlooking rate of SLN was 3.1%. The overlooked small SLN (2.9 × 3.3 × 3.1mm) was located at contralateral level IB. The CT numbers before, 2, 5, 10min after iopamidol injection, were 33 HU, 37 HU, 62 HU, 52 HU, respectively. The CT numbers of overlooked SLN 5 and 10min after the injection was higher than CT images scanned before the iopamidol injection. The enhancement of SLNs in CTL images after iopamidol injection should be compared sufficiently with CT images before iopamidol injection to avoid overlooking of SLNs in N0 early oral cancer.