Magnetic Resonance Lymphangiography Research Articles

Magnetic resonance lymphography to localise pelvic lymph nodes for intensity-modulated radiotherapy in gynaecological cancer

5070 Background: Intensity-modulated radiotherapy (IMRT) for gynaecological tumours requires accurate target volume delineation. Pelvic lymph nodes are poorly visualised on CT and MRI. Blood vessels with a 1–2cm margin are currently used as surrogate targets. A significant volume of small bowel is potentially irradiaited due to uncertainty about the exact lymph node position. Ultrasmall superparamagnetic iron oxide (USPIO), a novel MR contrast agent, localises in macrophages causing normal lymph nodes to appear black on MR images. This study used USPIO to determine the position of pelvic lymph nodes in relation to anatomic structures and develop guidelines for nodal irradiation. Methods: 15 patients with endometrial or cervical cancer had a diagnostic MRI (4mm slices) with subsequent USPIO administration and a repeat scan after 24 hours. All common iliac, presacral, external iliac, internal iliac and obturator nodes were outlined. On 10 scans, vessels were expanded by a margin of 15mm, 10mm, 7mm, 5mm and 3mm. The obturator and upper sacral regions were included with a corresponding margin. Nodal contours were overlaid on each expanded volume and analysed for coverage. Small bowel within each planning target volume (PTV) was measured. The resulting nodal irradiation guidelines were applied to the next 5 patients. Results: 836 nodal contours were evaluated. The mean number per patient was 56 (range 29–106). Contours covered by 15mm, 10mm, 7mm, 5mm and 3mm expansion were 99%, 96%, 90%, 77% and 63% respectively. The mean PTV bowel volume was 284, 204, 159, 130 and 102cm3. From these results, volume guidelines using an adjusted 7mm margin were applied to a further 5 patients resulting in 97% nodal coverage. Conclusions: MR lymphography with USPIO is an innovative technique to locate pelvic lymph nodes. Guidelines have been developed from these data for pelvic nodal irradiation with IMRT and conformal radiotherapy. A modified 7mm margin around vessels is recommended. This reduction in the margin reduces the small bowel volume within the PTV by 22% without compromising tumour coverage. No significant financial relationships to disclose.

MR lymphangiography: imaging strategies to optimize the imaging of lymph nodes with ferumoxtran-10.

Detection of local or regional metastases to lymph nodes is clinically important in virtually any type of primary tumor. Current imaging techniques rely heavily on the size criterion for characterization of nodal disease. However, size can be an ineffective parameter for diagnosis of tumor spread to lymph nodes. Magnetic resonance (MR) imaging performed before and after administration of ferumoxtran-10 is a promising technique for characterization of lymph nodes in patients with various primary tumors. Normal homogeneous uptake of ferumoxtran-10 in nonmetastatic nodes shortens the T2 and T2*, turning these nodes dark, whereas malignant nodes lack uptake and remain hyperintense. To optimize acquisition strategies, the following factors should be considered: the timing of contrast material-enhanced imaging, the section thickness, the imaging plane, and the imaging parameters for T2*-weighted sequences. In addition, MR imaging with ferumoxtran-10 allows presurgical mapping of lymph nodes and quantitative estimation of T2*.

Clinical Feasibility of Noncontrast-Enhanced Magnetic Resonance Lymphography of the Thoracic Duct

The dilatation of the thoracic duct was previously demonstrated in liver cirrhosis by lymphangiography, endoscopic ultrasound, and at autopsy. The evaluation of the morphologic change of the thoracic duct may be important in assessing the altered lymphodynamics in liver cirrhosis. The objectives of this study were to determine which combination of posture and breathing phase during noncontrast-enhanced magnetic resonance lymphography (MRL) provided the clearest images, and to evaluate the morphologic changes in the thoracic duct in healthy volunteers and patients with liver disease and malignancy. Prospective study. Community general hospital. Twenty-three healthy volunteers and 113 patients underwent the MRL examination using a three-dimensional, half-Fourier, fast spin echo sequence on a 1.5-T, whole-body magnetic resonance system. The appropriate posture and breathing phase of MRL to obtain the best visualization was first determined by trial on 14 healthy volunteers. Morphologic changes of the thoracic ducts were evaluated in 23 healthy volunteers including the 14 healthy volunteers for the first trial and 113 patients using this appropriate method. The width of the thoracic ducts in both patients and volunteers was measured. MRL with respiratory gating in the supine position depicted the thoracic duct well and was the most comfortable for the subjects. In 82 of 113 patients (72.6%), the thoracic ducts were entirely visualized from the diaphragm level to the subclavian region. The remaining 31 patients had ducts that could not be entirely visualized due to sections or short lengths that were obscured. The maximum diameter was 3.74 +/- 0.81 mm in all healthy volunteers, 6.98 +/- 2.77 mm in alcoholic cirrhosis, 4.12 +/- 1.51 mm in nonalcoholic cirrhosis, 3.76 +/- 1.10 mm in malignancy, and 3.60 +/- 0.80 mm in chronic hepatitis (mean +/- SD). The diameter in alcoholic cirrhosis was significantly greater than in other groups (p < 0.01). Respiratory gating in the supine position is the best MRL method for acquiring the clearest images. This may be a good method of detecting morphologic changes in the thoracic duct. The patients with alcoholic cirrhosis showed a greater thoracic duct diameter than other groups.

Potential of magnetic resonance lymphography with intrapulmonary injection of gadopentetate dimeglumine for visualization of the pulmonary lymphatic basin in dogs: preliminary results.

To evaluate a new approach of magnetic resonance (MR) lymphography with intraalveolar injection of a conventional extracellular contrast agent (gadopentetate dimeglumine) for imaging lymphatic basin draining from specific portions of the lung. Three-dimensional T1-weighted spoiled gradient-recalled echo MR sequence images were acquired serially before and for 40 minutes after intraalveolar injection of gadopentetate dimeglumine in a total of 14 anesthetized beagle dogs. Six of these dogs received 1 mL undiluted and low-concentration (75%) contrast agent into the same portion of the right caudal lobe during a 7-day interval. In all dogs, including these 6 dogs, MR lymphography was repeated with injection of the low-concentration contrast agent into different lung regions at 7-day intervals to evaluate the differences of the visualized draining lymphatic station. Lymphatic enhancement was quantified by percent increases of signal intensity against precontrast. Postmortem examination of the lymphatic anatomy was performed in 7 of these animals. In all dogs, the lymphatic station draining from the injection sites was visualized within 5 minutes after contrast injection. The maximum percent increase of signal intensity of the same middle tracheobronchial lymph nodes was significantly greater with a low-concentration (75%) contrast agent than with an undiluted one in the same 6 dogs (n = 6, 247.6 +/- 30.5% vs. 204.2 +/- 33.8%; P < 0.01). Different lymphatic stations draining from the different injection sites were visualized in all dogs. In a total of 12 MR studies that showed extended nodal enhancement after injection of the low-concentration contrast agent, the enhancement peak of the most proximal nodes (n = 12) from the injection sites appeared earlier than that of their distant nodes (n = 12), with a maximum percent increase of signal intensity of 249.8 +/- 42.4%. The visualized lymph nodes were found in the appropriate locations postmortem, with significant correlation for nodal sizes (r = 0.965; P < 0.0001). MR lymphography with low-concentration gadopentetate dimeglumine can quickly and sufficiently visualize the drainage lymphatic station from specific lung portions, and may have the potential of sentinel node mapping in lung cancer.

Indirect magnetic resonance lymphangiography of the head and neck: applications to conformal radiotherapy planning

Indirect magnetic resonance lymphangiography of the head and neck: applications to conformal radiotherapy planning

Visualization of Normal and Interrupted Lymphatic Drainage in Dog Legs With Interstitial MR Lymphography Using an Extracellular MR Contrast Agent, Gadopentetate Dimeglumine

The capability of the interstitial magnetic resonance lymphography (MR-LG) using a widely available extracellular contrast agent, gadopentetate dimeglumine, for the visualization of normal and interrupted lymphatic drainage was tested in dog legs. With a 7-day interval, 1 mL and 2 mL undiluted gadopentetate dimeglumine were injected intradermally into the dorsal foot of both hind legs of 12 dogs. T1-weighted 3-dimensional (3D) spoiled gradient-echo (repetition time/echo time = 6.7/1.6 ms) and maximum intensity projection (MIP) images covering the legs and pelvic region were acquired at 1.5 T for 10 minutes after 30 seconds gentle massage at the injection sites. These dogs also underwent the MR-LG with 2 mL of this contrast agent 7 days after surgical ligation of the popliteal lymphatic vessels. In the normal dogs, the interstitial MR-LG quickly and consistently visualized the direct connection of the lymphatic vessels and lymph nodes draining from the injection sites up to the inguinal region, without any late adverse effects. The enhancement effect was significantly greater with a 2-mL dose than with a 1-mL dose. After lymphatic obstruction, the MR-LG clearly revealed the anatomic compromises of the lymphatics, such as poor enhancement of the affected lymphatic vessels and lymph nodes, collateral lymphatic vessels, abnormal soft-tissue enhancement, and delayed lymphatic migration of the contrast agent. The topographic 3D images provided a comprehensive anatomy of these normal and compromised lymphatic drainage. Although gadopentetate dimeglumine is not lymphotropic, the interstitial MR-LG using this T1-contrast agent appears to have potential for quick and sufficient mapping of the lymphatic drainage from the injection sites and for the characterization of interrupted lymph flow.

Evaluation of retroperitoneal and pelvic lymph node metastases with MRI and MR lymphangiography.

Local, regional lymph node involvement is an essential prognostic factor and an important determinant of treatment choices for patients with retroperitoneal and pelvic cancer. Current cross-sectional imaging modalities, including computed tomography and magnetic resonance (MR) imaging, use the nonspecific criterion of size and are limited in their ability to differentiate benign from malignant lymph nodes. MR lymphography is a promising imaging modality in differentiating benign from metastatic lymph nodes and provides information on lymph node morphology and function. Ultrasmall superparamagnetic iron oxide (USPIO) particles with a long plasma circulation time are suitable as an MR contrast agent for intravenous MR lymphography. They are taken up by macrophages in normally functioning nodes and reduce the signal intensity of tissue in which they accumulate because of T2 and susceptibility effects of iron oxide. In metastatic nodes, macrophages are replaced by cancer cells, which lack reticuloendothelial activity and cannot take up USPIO. The main mechanisms that might explain a heterogeneous node appearance after USPIO injection are discussed. In published reports, USPIO has shown high degrees of sensitivity and specificity for characterizing lymph nodes in cancer patients. We review the development of USPIO compounds, their imaging characteristics, and our clinical experience.

Combined MR lymphangiography and MR imaging-guided needle localization of sentinel lymph nodes using Gadomer-17.

The goals of our study were to determine the technical feasibility of dynamic MR lymphangiography for detecting sentinel lymph nodes using Gadomer-17 contrast material to compare these results to the clinically standardized blue dye contrast agent, and to show MR imaging-guided needle localization marking of the sentinel nodes. Six anesthetized swine underwent MR imaging before and for 1 hr after interstitial injection of Gadomer-17 in the posterior tongue and intradermally in the stifle (knee). Using MR imaging guidance, we percutaneously placed a histology needle into the sentinel node or nodes. A standardized intraoperative sentinel node detection procedure was then performed using isosulfan blue contrast agent. Sentinel nodes identified on the MR images were compared with and matched to those identified by biopsy needle localization and the isosulfan blue contrast agent. RESULTS. Interstitial and intradermal injection of Gadomer-17 resulted in a lasting, increased MR signal in the regional lymph nodes. Seven sentinel nodes were identified in both the neck and the groin, with one pig showing two sentinel nodes in the neck and another showing two sentinel nodes in the groin. In all cases, the isosulfan blue contrast agent agreed with the location of the sentinel node determined by Gadomer-17 and marked with the needle. In this large animal model, dynamic MR angiography of sentinel lymph nodes is technically feasible using a contrast agent (Gadomer-17) and can be easily combined with MR imaging-guided needle localization.

Interstitial Magnetic Resonance Lymphography with Gadobutrol in Rats

To evaluate the contrast kinetics of gadobutrol for interstitial MR lymphography. In 11 rats, 0.5 mL undiluted gadobutrol was injected subcutaneously into the hind paw. Contrast kinetics were measured in lymph nodes, kidney, liver, muscle, and blood of six animals using a time-resolved 2D GRE sequence. Additionally, high-resolution 3D T1-weighted data sets were obtained in five animals. Immediately after injection, a pronounced signal intensity loss was observed in popliteal, inguinal and aorto-iliac lymph nodes, followed by a continuous signal intensity increase. From the data peak concentrations of up to 78 mmol/L were estimated for selected lymph nodes. A contrast enhancement was also observed in kidneys, liver, muscle, and blood. Regional lymphatic vessels, the thoracic duct, as well as popliteal, inguinal, aorto-iliac, and axillary lymph node groups could be visualized with the high-resolution 3D MRI. Gadobutrol is suitable for interstitial MR lymphography, as it rapidly appears in the lymphatic system. Based on estimates of local tissue concentrations future studies have to assess the optimal contrast agent dosage. Furthermore, the investigation of metastatic lymph nodes is required to evaluate the further potential of gadobutrol for interstitial MR lymphography.

MR Lymphangiography for Detection of Minimal Nodal Disease in Patients with Prostate Cancer

As prostate cancer is the second leading cause of cancer death in men in the USA, the clinical challenge is to develop methods that allow early diagnosis, accurate staging and precise treatment. Metastases to local and distant lymph nodes play a major role in the choice of therapy and in predicting outcome of these patients ( 1 Wilkinson BA Hamdy FC State-of-the-art staging in prostate cancer. BJU International. 2001; 87: 423-430 Crossref PubMed Google Scholar ). Clinical examination to detect lymph node metastases alone is inadequate and surgical dissection and serial histologic examinations are currently accepted “yardsticks”. In the past years, there has been debate about the pros and cons of total lymph node resection, particularly because of its morbidity, lengthiness of the surgical procedure and the resources necessary for complete pathologic evaluation of harvested nodes ( 2 Paul DB Loening SA Narayana AS Culp DA Morbidity from pelvic lymphadenectomy in staging carcinoma of the prostate. J Urol. 1983; 129: 1141-1144 Abstract Full Text PDF PubMed Scopus (71) Google Scholar ). Non-invasive imaging techniques for the detection of lymph node metastases would be of great help and a potential cost savings (imaging study vs. surgical lymphadenectomy) in the evaluation and re-staging of cancer patients. All current cross sectional imaging techniques (US, CT and MRI) have a relatively low sensitivity in detecting nodal metastases primarily because detection relies on insensitive size criteria (>10 mm short axis) ( 3 Rorvik J Halvorsen O Espeland A Haukaas S Inability of refined CT to assess local extent of prostatic cancer. Acta Radiol. 1993; : 39-42 Crossref PubMed Google Scholar ). Ultrasmall superparamagnetic iron oxide (USPIO) is a relatively new RES targeted MR contrast agent that is known for lymph node uptake ( 4 Anzai Y McLachlan S Morris M Saxton R Lufkin R Dextran-coated superparamagnetic iron oxide, an MR contrast agent for assessing lymph nodes in the head and neck. AJNR Am J Neuroradiol. 1994; 15: 87-94 PubMed Google Scholar , 5 Anzai Y Prince M Iron oxide-enhanced MR lymphography: the evaluation of cervical lymph node metastases in head and neck cancer. J Magn Reson Imaging. 1997; 7: 75-81 Crossref PubMed Scopus (86) Google Scholar , 6 Harisinghani M Saini S Slater G Schnall M Rifkin M MR imaging of pelvic lymph nodes in primary pelvic cancer with USPIO (Combidex). 1997 Contrast Medical Research Conference. Acad Radiol, Kyoto, Japan1997 Google Scholar , 7 Harisinghani MG Saini S Weissleder R et al. MR lymphangiography using ultrasmall superparamagnetic iron oxide in patients with primary abdominal and pelvic malignancies: radiographic-pathologic correlation. AJR Am J Roentgenol. 1999; 172: 1347-1351 Crossref PubMed Scopus (154) Google Scholar , 8 Harisinghani MG Saini S Hahn PF Weissleder R Mueller PR MR imaging of lymph nodes in patients with primary abdominal and pelvic malignancies using ultrasmall superparamagnetic iron oxide (Combidex). Acad Radiol. 1998; 5 (discussion S183–164): S167-169 Abstract Full Text PDF PubMed Google Scholar , 9 Bellin MF Roy C Kinkel K et al. Lymph node metastases: safety and effectiveness of MR imaging with ultrasmall superparamagnetic iron oxide particles—initial clinical experience. Radiology. 1998; 207: 799-808 PubMed Google Scholar , 10 Bellin R, Kinkel K, Challier E, et al. MR lymphography with ultrasmall iron oxide particles in patients with urologic and pelvic cancer. European Congress of Radiology. Vienna, 1997 Google Scholar , 11 Weissleder R Elizondo G Wittenberg J Lee A Josephson L Brady T Ultrasmall superparamagnetic iron oxide: an intravenous contrast agent for assesing lymph nodes with MR imaging. Radiology. 1990; 175: 494-498 PubMed Google Scholar , 12 Weissleder R Heautot J Schaefer B et al. MR lymphography: Study of a high-efficiency lymphotrophic agent. Radiology. 1994; 191: 225-230 PubMed Google Scholar , 13 Weissleder R Elizondo G Wittenberg J Rabito C Bengele H Josephson L Ultrasmall superparamagnetic iron oxide: Characterization of a new class of contrast agents for MR imaging. Radiology. 1990; 175: 489-493 PubMed Google Scholar ). The purpose of this study was to evaluate the utility of USPIO (Combidex™ Sinerem®) induced signal intensity changes in lymph nodes for staging patients with prostate cancer. Also assessed was the utility of postcontrast images alone in characterizing lymph nodes.

Interstitial MR lymphangiography for the detection of sentinel lymph nodes

The challenge for implementation of sentinel lymph node biopsy is to develop a reliable minimally invasive technique that identifies all possible sentinel nodes with high temporal and spatial resolution. This study evaluated the use of a magnetic resonance imaging (MRI) contrast agent (USPIO) for preoperative sentinel node detection. Anesthetized pigs received interstitial or intradermal injections of ultra small superparamagnetic of iron oxide (USPIO) (0.2 or 5 mg Fe) in the L/R posterior tongue and stifles (knee) respectively. MRI was done before, during injection and at 0.25, 0.5, 1, 2, 4, 6, 24, and 48 hr after which isosulfan blue sentinel node mapping was done. In the tongue, both doses of USPIO identified the sentinel node in the early images. No additional nodes were detected by MR at 24 or 48 hr. In the hind limb, sentinel nodes identified on the early MR images were also identified by the isosulfan blue. In both locations, the higher dose also identified secondary nodes some of which were also identified by the isosulfan blue. All sentinel nodes that were identified by USPIO on MRI were noted to be stained brown at the time of dissection. Interstitial MR lymphangiography is a useful technique for the detection of sentinel lymph nodes. This method provides excellent simultaneous temporal and spatial resolution, is minimally invasive, and can be performed preoperatively.

Interstitial MR lymphography with gadoterate meglumine: initial experience in humans.

Magnetic resonance (MR) lymphography was performed in five healthy volunteers and three patients (two adults and one infant). Subcutaneous administration of gadoterate meglumine in the foot allowed visualization of draining lymph vessels and nodes. In one patient, an inguinal fluid collection could be characterized as a lymphocele. In the infant, a chylothorax was diagnosed. The authors conclude that interstitial MR lymphography with commercially available compounds is feasible.

Interstitial MR lymphography with a conventional extracellular gadolinium-based agent: assessment in rabbits.

To evaluate gadoterate meglumine as a contrast agent for interstitial magnetic resonance (MR) lymphography in combination with an adapted fast three-dimensional (3D) MR sequence. In 12 New Zealand White rabbits, 0.5 mL of undiluted gadoterate meglumine was injected subcutaneously into the dorsal foot pad (n = 9) or the foreleg (n = 3) bilaterally. Immediately after administration, a slight massage was performed at the injection site. Imaging was performed with a 3D spoiled gradient-recalled echo sequence (6.7/1.6 [repetition time msec/echo time msec]; field of view, 28.0 x 19.6; two signals acquired) similar to that used for 3D MR angiography. Thus, 3D maximum intensity projection images could be obtained. Images were obtained before injection and 5, 15, 30, 60, and 120 minutes after injection. In the hind legs, as many as four successive lymph node groups were depicted with maximum enhancement after 5-15 minutes for the popliteal lymph node group, 15-30 minutes for the inguinal lymph group, and 30-60 minutes for the iliac-paraaortal lymph node group; the iliac-paraaortal lymph node group was not consistently enhanced. In the forelegs, four successive lymph node groups, including axillary and mediastinal lymph node groups, showed marked gadolinium uptake, with maximum enhancement 5-15 minutes after injection. As a widely tested positive-enhancing T1 contrast agent with favorable safety features, gadoterate meglumine allows the depiction of three to four successive lymph node groups early after subcutaneous injection. With the sequence used, 3D MR lymphangiograms can be obtained.

Magnetic resonance lymphography of profundus lymph nodes with liposomal gadolinium-diethylenetriamine pentaacetic acid.

Lymphography, especially imaging of profundus lymph nodes, is a useful tool for diagnosis of cancer metastases in lymph nodes. However, positive enhancement agents for magnetic resonance lymphography (MRL) have not been available, since the positive imaging agents so far introduced are low-molecular-weight materials that are not trapped in lymph nodes. For the purpose of improved positive enhanced MRL, we employed liposomes as carriers of a positive enhancer, gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA). Magnetic resonance (MR) imaging was performed after subcutaneous injection of Gd-liposomes into the hind feet of rabbits which had reactive enlarged retroperitoneal lymph nodes. As a result, not only popliteal but also profundus retroperitoneal lymph nodes were positively enhanced by Gd-liposomes, especially after 20 min massage of the injected sites. Gd-Liposomes containing dipalmitoylphosphatidylglycerol were more effective than Gd-liposomes containing palmityl-D-glucuronide, a type of long-circulating liposomes, suggesting that liposomal accumulation in lymph node is, at least partly, mediated by the trapping of liposomes by macrophages. These data show that liposomes modified with Gd-DTPA are effective for positive enhancement of both regional and profundus lymph nodes in MR lymphography.

Distribution of iron oxide nanoparticles in rat lymph nodes studied using electron energy loss spectroscopy (EELS) and electron spectroscopic imaging (ESI).

Superparamagnetic iron nanoparticles have been developed as contrast agents for magnetic resonance lymphography. The kinetics of uptake of these particles has not yet been accurately determined. We have therefore monitored the distribution of individual iron particles (ferumoxtran, AMI-227, Sinerem) in rat lymph nodes 1.5, 3, 6, 12, and 24 hours after i.v. injection (two rats per time point). The ultrastructural distribution of the iron was determined by energy-filtered transmission electron microscopy (EFTEM). This method allows the identification of elements using element-specific energy-loss electrons. Iron was identified by the Fe-L(2,3) edge (EELS), and iron maps were obtained using iron-specific electrons for imaging (ESI). The background was calculated by simplex optimization (EELS) and by the two-window method (ESI). Ferumoxtran particles were regularly observed at the periphery of the lymph nodes but not in their centers. Isolated iron particles were seen extracellularly within lymph vessels and, 3 hours after injection, as small dots in phagocytic cells. Numerous dense clusters appeared within the cells at later times (6 and 12 hours after injection). These results suggest that the contrast agent moves rapidly across the capillary wall to the lymph and is then taken up by phagocytic cells. J. Magn. Reson. Imaging 2000;12:505-509.

Thoracic duct: visualization at nonenhanced MR lymphography--initial experience.

In six healthy volunteers, the thoracic duct was examined at magnetic resonance (MR) lymphography without contrast agent. With a 1.5-T clinical imager, a short echo spacing, three-dimensional, half-Fourier fast spin-echo sequence with electrocardiographic gating was employed to depict the thoracic duct along the thoracic aorta. The images clearly depicted the main duct in the region of the thoracic aorta in all six volunteers, drainage into the left subclavian region in four, and the cisterna chyli in one.

Anatomic study of the pelvis in carcinoma of the uterine cervix as related to the box technique

Purpose: To review the radiation therapy “box” technique for cancer of the cervix by means of magnetic resonance imaging (MRI), lymphangiography, and anatomic studies on cadavers. Methods and Materials: From 1993 to 1996, the anatomic borders of the “box” technique used at our Radiation Oncology Department—the superior border of the AP-PA fields at the inferior edge of L4; the inferior border at the inferior edge of the ischium; the lateral borders placed 2.5 cm outside of the bony pelvis rim; the anterior border of the lateral fields over the anterior edge of the pubic symphysis; and the posterior at the S2–S3 interspace—were reviewed in 35 sagittal MRI and 10 lymphangiographies of patients with FIGO IB (6), IIA (6), IIB (19), IIIB (3), and IVA (1). An anatomic revision was conducted on 30 cadavers to identify aortic bifurcation, lymphatic nodes, and uterus flexion. Results: In 50% of the patients with FIGO IB, the posterior border of the lateral field was inadequate to encompass the planning target volume (PTV), and in 67% with Stage IIA. In IIB, the anterior border was inadequate in 1 patient, and the posterior in 8 (42%). In IIB and IVA patients, the PTV was not encompassed. When correlating the anterior and posterior borders of the lateral field and the treatment volume in the 35 sagittal MRIs, the posterior border of the lateral field was inadequate in 49%, and the anterior border in 9% of the cases. According to the lymphangiography, the portals encompassed the external iliac nodes. Dissected female pelvises revealed that the aortic bifurcation occurred at the level of the inferior L4 edge in 80% of the cadavers. There was no correlation between uterus flexion in MRIs and in cadavers. Conclusion: The design of the lateral fields of the four-field technique for the irradiation of the uterine cervix based on anatomic bone references failed to encompass the planning-target volume in a significant number of patients.

Interstitial MR and CT lymphography with Gd-DTPA-co-α, ω-diaminoPEG(1450) and Gd-DTPA-co-1,6-diaminohexane polymers: Preliminary experience

The authors assessed the efficacy of two gadolinium-based polymers used as lymphotrophic contrast media for computed tomography (CT) and magnetic resonance (MR) imaging. Two gadolinium-based polymers, gadolinium diethylenetriaminepentaacetic acid (DTPA)-co-1,6-diaminohexane (NC 22181) and Gd-DTPA-co-alpha, omega-diamino-polyethylene glycol(1450) (NC-66368), were formulated at a concentration of 80 mmol/L gadolinium. Doses of 0.1, 0.25, 1.0, or 2.0 mL per paw were administered subcutaneously into the hindpaws of normal rabbits. Spin-echo T1-weighted MR imaging (1.5 T) of rabbit popliteal and iliac nodes was performed before and immediately, 10 minutes, 2-3 hours, and 24 hours after injection. CT was performed 2-3 hours after injection of the high doses only. MR imaging revealed prompt enhancement of the popliteal nodes with both polymers at doses of 0.25 mL and above. For doses of 1.0 mL or less per paw, nodal percentage enhancement was maximal at 2 hours and then declined at 24 hours. At the highest doses, however, a reservoir of subcutaneous contrast material remained at the injection site and resulted in peak enhancement at 24 hours. At CT, popliteal node enhancement was faintly visible 2-3 hours after the administration of NC 22181. At lower doses, no enhancement was appreciable at CT. At 80 mmol/L formulations, the two gadolinium-based polymers provide excellent popliteal nodal enhancement on MR images. In addition, high doses of one polymer (NC 22181) were sufficiently concentrated in popliteal nodes to be visible on CT scans. Thus, this agent may be useful for both CT and MR lymphography.

MR lymphangiography in infants, children, and young adults.

Our objective was to offer a preliminary description of MR lymphangiography; its uses and limitations; and its findings in infants, children, and young adults. Twenty-nine patients underwent 32 MR lymphangiographic examinations for evaluation of vascular malformations, other masses, soft-tissue swelling, gigantism, fluid accumulation, or pain. MR lymphangiography was based on a heavily T2-weighted fast spin-echo sequence and a maximum-intensity-projection algorithm. We assessed the axial and off-axial lymphatic channels in conjunction with MR venography to help differentiate veins from lymphatics. Correlation was made with published lymphangiograms and anatomic diagrams to assist interpretation and (when available) with histologic specimens (n = 11) for validation. Presumed lymphatic channels were seen universally, although 14 examinations showed incomplete venous signal suppression. Lymphatic channels appeared normal in eight children and in 20 of the 21 asymptomatic contralateral limbs. Ten patients had an increased number and size of off-axial channels, including seven children with large, diffuse low-flow vascular malformations. Enlarged axial and off-axial channels were seen in five patients, four of whom had Klippel-Trénaunay syndrome. Six patients, each with an extensive hemangioendothelioma, Klippel-Trénaunay syndrome, Gorham syndrome, or unilateral body edema, showed absence or interruption of axial channels. MR lymphangiography appears to be a useful noninvasive technique to study superficial and deep lymphatic channels in children with local or diffuse vascular lesions or swelling of extremities. Its limitations notwithstanding, the technique may offer further insight into the nature of vascular anomalies, may direct therapy, and may predict prognosis.

A modular lymphographic magnetic resonance imaging contrast agent: contrast enhancement with DNA transfection potential.

A gadolinium-chelated liposomal contrast agent has been prepared, and magnetic resonance imaging (MRI) efficacy has been examined by indirect magnetic resonance lymphography. A lipidic N,N'-dimethylethylenediamine derivative (4) containing a 10,12-diyne-diacyl domain was treated with DTPA anhydride followed by GdCl3 complexation. The complex was confirmed using MALDI spectrometry. An equimolar mixture of the Gd-chelate lipid and a commercially available diyne-PE was formulated as a liposome suspension and irradiated with UV light prior to imaging experiments. Subcutaneous injection of the liposomal gadolinium agent and subsequent MRI of rabbit axillary and popliteal lymph nodes revealed significant contrast enhancement up to 4 h postinjection. To explore the possibility of imaging a DNA transfection event, the gadolinium contrast mixture was formulated with the cationic transfection lipid DOTAP and complexed with the reporter gene encoding luciferase. DNA transfection studies on the NIH3T3 cell line confirmed the transfection activity of the dual-purpose contrast agent and exemplified the potential toward development of an imaging and DNA delivery vehicle.