Nonenhanced magnetic resonance lymphoductography: visualization of lymphatic system of the trunk on 3-dimensional heavily T2-weighted image with 2-dimensional prospective acquisition and correction

The cisterna chyli: a systematic review of definition, prevalence, and anatomy

The cisterna chyli is a lymphatic structure found at the caudal end of the thoracic duct that receives lymph draining from the abdominal and pelvic viscera and lower limbs. In addition to being an important landmark in retroperitoneal surgery, it is the key gateway for interventional radiology procedures targeting the thoracic duct. A detailed understanding of its anatomy is required to facilitate more accurate intervention, but an exhaustive summary is lacking. A systematic review was conducted, and 49 published human studies met the inclusion criteria. Studies included both healthy volunteers and patients and were not restricted by language or date. The detectability of the cisterna chyli is highly variable, ranging from 1.7 to 98%, depending on the study method and criteria used. Its anatomy is variable in terms of location (vertebral level of T10 to L3), size (ranging 2-32 mm in maximum diameter and 13-80 mm in maximum length), morphology, and tributaries. The size of the cisterna chyli increases in some disease states, though its utility as a marker of disease is uncertain. The anatomy of the cisterna chyli is highly variable, and it appears to increase in size in some disease states. The lack of well-defined criteria for the structure and the wide variation in reported detection rates prevent accurate estimation of its natural prevalence in humans.

Magnetic Resonance Lymphangiography of the Central Lymphatic System: Technique and Clinical Applications

Magnetic resonance lymphangiography (MRL) is a noninvasive imaging technique that can be used in the management of lymphatic disorders to delineate the central lymphatic system for treatment planning. This article reviews the MRL technique, its advantages, limitations, indications, and impact on patient management. Level of Evidence 5 Technical Efficacy Stage 3 J. MAGN. RESON. IMAGING 2021;53:374-380.

The Visibility of the Terminal Thoracic Duct Into the Venous System Using MR Thoracic Ductography with Balanced Turbo Field Echo Sequence

RATIONALE AND OBJECTIVES

Magnetic resonance thoracic ductography (MRTD) with balanced turbo field echo (bTFE) can visualize both the thoracic duct and its surrounding vessels. This study aimed to investigate the visibility of the terminal thoracic duct into the venous system in the subclavian region using MRTD with bTFE.

MATERIALS AND METHODS

MRTD was performed with bTFE as a preoperative workup comprising respiratory gating on a 1.5-T magnetic resonance system for patients with esophageal cancer. The portion and the number of terminal thoracic ducts into the venous system and preterminal branching in the left subclavian region were assessed using MRTD in 132 patients. The confidence level of the visibility using MRTD was also evaluated.

RESULTS

The most frequent terminal portion of the thoracic duct was the jugulovenous angle (92 patients, 69.7%), followed by the subclavian vein (27 patients, 20.5%) and the internal jugular vein (8 patients, 6.1%). Four patients also exhibited double entry of the thoracic duct into the venous system. The preterminal branching was single in 96 patients (72.7%) and multiple in 36 patients (27.3%). The confidence level of the visibility of the thoracic duct using MRTD was absolutely certain in 112 patients (84.8%) and was somewhat certain in 20 patients (15.2%).

CONCLUSIONS

MRTD with bTFE is a robust imaging modality to visualize the terminal portion of the thoracic duct into the venous system in the subclavian region.

Magnetic resonance thoracic ductography assessment of serial changes in the thoracic duct after the intake of a fatty meal

The thoracic duct, a terminal lymph vessel, is thought to dilate after the intake of a fatty meal. However, this physiological change has not been well explored in vivo. Therefore, the present study aimed to assess serial changes in the thoracic duct after the intake of a fatty meal using magnetic resonance thoracic ductography (MRTD). Eight healthy volunteers were subjected to one MRTD scan before a fatty meal and eight serial MRTD scans every hour thereafter. The cross-sectional areas of the thoracic duct were estimated using MRTD measurements of the diameters of the thoracic duct at the upper edge of the aortic arch, the tracheal bifurcation, the mid-point between the tracheal bifurcation and the left part of the diaphragm and the left part of the diaphragm. The change-rates in these areas were calculated before and after the fatty meal intake, and the maximal change-rate and timing of its achievement were determined for each subject. The summed change-rates in the four portions of the thoracic duct ranged from -40.1 to 81.3%, with maximal change-rates for each subject ranging from 22.8 to 81.3% (mean, 50.4%). Although individual variations were observed, most subjects (88.9%) exhibited a maximal change-rate at 4-6 h after meal intake, with subsequent decreases at 7-8 h. In conclusion, MRTD revealed a tendency toward thoracic duct enlargement at 4-6 h after the intake of a fatty meal, followed by contraction.

Non-enhanced MR lymphography of the thoracic duct: improved visualization following ingestion of a high fat meal-initial experience

PURPOSE

The objective of this study was to compare the clarity of magnetic resonance lymphography (MRL) images of the thoracic duct (TD) obtained from subjects following an overnight fast with those obtained from the same subjects after ingestion of a high fat meal.

METHODS

Nineteen healthy volunteers were included in this study. TD images were acquired on a 3·0T MRI system with the imaging sequence of magnetic resonance cholangiopancreatography. TD MRL images were obtained from subjects following an overnight fast and from the same subjects 3-4 h after ingestion of a high fat meal. Images were displayed in maximum intensity projection format and degree of visualization was evaluated using a scoring system.

RESULTS

The mean TD score obtained following an overnight fast was significantly lower than the mean TD score obtained 3-4 h after ingestion of a high fat meal (P<0·05).

CONCLUSION

The clarity of TD MRL images is improved if subjects have ingested a high fat meal 3-4 h prior to examination.

Balanced Turbo Field Echo with Extended k-space Sampling: A Fast Technique for the Thoracic Ductography

We evaluated the visibility of the thoracic duct by fast balanced turbo field echo with extended k-space sampling (bTFEe). The thoracic duct of 10 healthy volunteers was scanned by bTFEe using a 1.5-T magnetic resonance imaging (MRI), which was acquired in approximately 2 minutes. Three-dimensional (3D) turbo spin-echo (TSE) was obtained for comparison. The thoracic duct including draining location of the venous system was overall well visualized on bTFEe, compared to TSE.

Bridging the divide between pathogenesis and detection in lymphedema

While our understanding of the lymphatic system has improved substantially in the past few decades, the translation of this knowledge into improved healthcare solutions for patients suffering from secondary lymphedema has been severely limited. The challenge facing clinicians is two-fold. First, there is no reliable, affordable, diagnostic capable of detecting the disease before symptoms of the lymphedema develop and the efficacy of treatment options becomes limited. Second, our understanding of the disease pathogenesis, its risk factors, and the underlying physiologic mechanisms is still in its infancy. These two challenges go hand in hand as limited diagnostic options have hindered our ability to understand lymphedema progression, and the lack of known underlying mechanisms involved in the disease prohibits the development of new diagnostic targets. This review serves to discuss the recent developments in clinical and lab research settings of both lymphedema diagnostic technologies and our understanding of the mechanisms driving disease risk and progression. We will show how these two lines of research are synergistically working with the ultimate goal of improving patient outcomes for those suffering from this horrible disease, identifying key areas of further research that are warranted to move the field forward and provide clinical relief for this neglected patient population.

Breast and gynecologic cancer-related extremity lymphedema: a review of diagnostic modalities and management options

Lymphedema remains a poorly understood entity that can occur after lymphadenectomy. Herein, we will review the pathogenesis of lymphedema, diagnostic modalities and the natural history of extremity involvement. We will review the incidence of upper extremity lymphedema in patients treated for breast malignancies and lower extremity lymphedema in those treated for gynecologic malignancy. Finally, we will review traditional treatment modalities for lymphedema, as well as introduce new surgical treatment modalities that are under active investigation.

Thoracic duct and cisterna chyli: evaluation with multidetector row CT

OBJECTIVES

The aim of this study was to evaluate the normal anatomy of the thoracic duct and cisterna chyli obtained by axial and multiplanar reformation (MPR) images of 1 mm slice thickness using multidetector row CT (MDCT).

METHODS

We evaluated the ability of MDCT to examine the normal anatomy of the thoracic duct and cisterna chyli. The axial and coronal images of thoracoabdominal MDCT images obtained in 50 patients (20 females and 30 males; mean age, 63.5 years; range, 32-81 years) were reviewed between January and October 2005. We excluded patients with malignant neoplasms, inflammation or vascular diseases (e.g. aortic aneurysm, aortic dissection) and those with a history of thoracoabdominal surgery. The thoracic duct was divided into three anatomical sections: the upper, middle and lower. We evaluated the degree of visualisation and the maximum size of the thoracic duct. We also evaluated the degree of visualisation, maximum size, configuration and location of the cisterna chyli.

RESULTS

Visualisation of the thoracic duct and cisterna chyli was almost 100% on axial and coronal images. The lower section of the thoracic duct was most clearly visualised among the three sections. There was little difference in the maximum size of the thoracic duct among the three sections. The cisterna chyli was most frequently located at the Th12 or L1 level, and the most common type was the "straight thin tube type".

CONCLUSION

Axial and MPR images of 1 mm slice thickness using MDCT can clearly depict the thoracic duct and cisterna chyli.

Thoracic duct visualization: combined use of multidetector-row computed tomography and magnetic resonance imaging

PURPOSE

The objective of the study was to assess the ability of magnetic resonance imaging (MRI) and helical multidetector-row computed tomography (MDCT) to visualize the thoracic duct in esophageal cancer patients.

METHODS

Sixty esophageal cancer patients underwent preoperative MDCT and MRI using 3-dimensional balanced turbo-field-echo sequence. The visualization grades by MDCT, MRI, and a combination of MDCT and MRI were scored in 4 segments of the thoracic duct (cervical, upper, middle, and lower).

RESULTS

In the cervical, middle, and lower segments, MRI provided significantly higher visualization grades than MDCT. In all segments, combined MDCT and MRI resulted in higher grades than MDCT alone. In addition, combined MDCT and MRI successfully allowed visualization of the cervical, upper, middle, and lower segments of the thoracic duct in 46 (76.7%), 50 (83.3%), 58 (96.7%), and 60 (100%) patients, respectively.

CONCLUSIONS

Combination of MDCT and MRI allows noninvasive thoracic duct visualization, providing 3-dimensional information on other thoracic structures.

Morphological features and clinical feasibility of thoracic duct: detection with nonenhanced magnetic resonance imaging at 3.0 T

PURPOSE

To evaluate the detection of the thoracic duct using nonenhanced magnetic resonance imaging (MRI) and to determine the influence of some related disorders on the lymphatic duct.

MATERIALS AND METHODS

Highly fluid-sensitive sequence and fat-suppressed T2-weighted imaging (FS-T2WI) were performed in a total of 139 cases. The axial and coronal images were used to locate the thoracic duct and the measurement and evaluation of its dimensions were performed using a 3D maximum intensity projection (MIP) reconstruction image. The differences in the dimensions among control, portal hypertension, and common bile duct obstruction groups were compared using one-way analysis of variance.

RESULTS

The cisterna chyli was shown in 91% of cases on FS-T2WI, while the thoracic duct appeared in 70% of the MIP images. The common configuration of the cisterna chyli was tubular or saccular in 73%. Eighty thoracic ducts had a slight turn declining to the left at the level of T8-10. There was a significant difference in the transverse diameter of the thoracic duct between the portal hypertension group and other groups (F = 5.638, P = 0.005).

CONCLUSION

Nonenhanced MRI is feasible for locating and depicting the morphological features of the thoracic duct. Portal hypertension may influence the dimension of the thoracic duct.

Diagnosis and management of lymphatic vascular disease

The lymphatic vasculature is comprised of a network of vessels that is essential both to fluid homeostasis and to the mediation of regional immune responses. In health, the lymphatic vasculature possesses the requisite transport capacity to accommodate the fluid load placed upon it. The most readily recognizable attribute of lymphatic vascular incompetence is the presence of the characteristic swelling of tissues, called lymphedema, which arises as a consequence of insufficient lymph transport. The diagnosis of lymphatic vascular disease relies heavily upon the physical examination. If the diagnosis remains in question, the presence of lymphatic vascular insufficiency can be ascertained through imaging, including indirect radionuclide lymphoscintigraphy. Beyond lymphoscintigraphy, clinically-relevant imaging modalities include magnetic resonance imaging and computerized axial tomography. The state-of-the-art therapeutic approach to lymphatic edema relies upon physiotherapeutic techniques. Complex decongestive physiotherapy is an empirically-derived, effective, multicomponent technique designed to reduce limb volume and maintain the health of the skin and supporting structures. The application of pharmacological therapies has been notably absent from the management strategies for lymphatic vascular insufficiency states. In general, drug-based approaches have been controversial at best. Surgical approaches to improve lymphatic flow through vascular reanastomosis have been, in large part, unsuccessful, but controlled liposuction affords lasting benefit in selected patients. In the future, specifically engineered molecular therapeutics may be designed to facilitate the controlled regrowth of damaged, dysfunctional, or obliterated lymphatic vasculature in order to circumvent or mitigate the vascular insufficiency that leads to edema and tissue destruction.

New horizons for imaging lymphatic function

In this review, we provide a comprehensive summary of noninvasive imaging modalities used clinically for the diagnosis of lymphatic diseases, new imaging agents for assessing lymphatic architecture and cancer status of lymph nodes, and emerging near-infrared (NIR) fluorescent optical imaging technologies and agents for functional lymphatic imaging. Given the promise of NIR optical imaging, we provide example results of functional lymphatic imaging in mice, swine, and humans, showing the ability of this technology to quantify lymph velocity and frequencies of propulsion resulting from the contractility of lymphatic structures.