Lymphoscintigraphy

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Lymphoscintigraphy

Postby patoco » Tue Jun 27, 2006 11:24 pm

Lymphoscintigraphy

Lymphedema People

http://www.lymphedemapeople.com

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IS THERE A "TEST" FOR LYMPHEDEMA?

Keywords: Lymphoscintigraphy; Lymphoscintography; Lymphedema

There is a question that is asked continuously in the online groups I am a member of is, "Is there a test that can be done to accurately determine whether or not you have lymphedema?"

Yes, there is. It is called lymphoscintigraphy. In this procedure a blue dye called 99mTc-sulfur colloid is injected into the swollen limb. The substance then travels and is tracked until it reaches the lymphatic obstruction.

It is safe because it is minimally invasive. It is accurate and from this test, the lymphedema can be classified by type, hyperplasia, hypoplasia, or absence of lymphatics.

There are only two downsides to the test. It has to be done separately for each limb that is affected and it won't pick up the deeper lymphatics. These deeper lymphatics are responsible for the transport of about 10% of the bodies fluid.

It also needs to be noted that this procedurehas replaced the old test called lymphangiogram. This test was discontinued because of potential complications involved in its oils based tracer dye. No one should be having a lymphangiogram in this day and age.

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What is Lymphoscintigraphy?

Lymphoscintigraphy provides a view of the workings of the lymphatic system, which is a network of small channels, like arteries and veins, that transport the fluid and cells of the immune system through the lymph nodes and throughout the body. This fluid, called lymph, normally flows slowly from the periphery toward the center of the body and into the general circulation. If lymphatic flow is blocked, the areas of drainage that are affected can become swollen.

A scintigram is a type of picture that uses a radiopharmaceutical (a radioactive drug), which is injected or taken orally, that makes the lymphatic system visible to specialized cameras. The study is performed in the Nuclear Medicine section of the hospital, where the radiopharmaceuticals are prepared and the pictures are taken. Lymphoscintigraphy can be helpful for localizing points of blockage and is also important for identifying abnormal lymph nodes and planning a biopsy or surgery for suspicious areas. Generally, the radiation dose is similar to that of a standard x-ray examination.

What are some common uses of the procedure?

Lymphoscintigraphy can assist the physician in diagnosing diseases. It can help detect tumors, infection and other disorders such as the following:

Lymphoscintigraphy can help diagnose lymphedema, a condition in which lymphatic fluid accumulates in soft tissues and may lead to inflammation and obstruction. This nuclear medicine test has all but replaced lymphangiography, a diagnostic x-ray procedure that used an oil-based contrast material that required surgical incisions on both feet to expose and inject the lymphatics directly.

Lymph flow in an arm or leg may be evaluated with lymphoscintigraphy by injecting radioactive material into a web space between the fingers or toes and recording images for 60 minutes. Local anesthesia is not necessary.

When planning surgery for a breast tumor, it is helpful to assess the lymphatic drainage beforehand to identify the sentinel lymph node (the first lymph node that receives lymph drainage from the tumor site) for excisional biopsy. A radiopharmaceutical is injected either just beneath the skin around the areola (nipple); at two to four sites around the tumor; beneath the skin above the tumor; or into the tumor itself on the day of surgery. Imaging usually is completed within 30 minutes, but may take up to one to two hours. Lymphoscintigraphy of the breast is very safe. Side effects are infrequent, and morbidity is much reduced compared with axillary lymph node dissection, which formerly was the routine staging procedure for patients with breast cancer and no obvious spread (metastasis).

Malignant melanoma is an aggressive form of skin cancer that may spread rapidly to distant body sites. Lymphoscintigraphy may be performed preoperatively in order to identify the sentinel lymph node. A tumor-negative sentinel lymph node is strong evidence that there has not been spread of the tumor. This is important for staging the disease and planning treatment management.

How should I prepare for the procedure?

No special preparation is needed for lymphoscintigraphy.

What does the equipment look like?

During lymphoscintigraphy you will lie down on a scanning table. Consequently, the only piece of equipment you may notice is the specialized nuclear imaging camera used during the procedure. It is a large, round device enclosed in a metallic housing and suspended over the examination table. The camera sometimes is located within a large, doughnut-shaped structure similar in appearance to a computed tomography (CT) scanner. A nearby computer console, often in an adjacent room, processes the data from the procedure.

How does the procedure work?

With regular x-ray examinations, an image of the body is made by passing x-rays through the body part from an outside x-ray source. In contrast, with nuclear medicine a radioactive substance called a radiopharmaceutical or radiotracer localizes in a certain body part (or parts) which emits gamma rays that are detected by a gamma camera. The gamma camera sends the information to a computer that develops the image. Scanning times may vary considerably.

The most commonly used radiopharmaceutical in the United States for lymphoscintigraphy is called technetium-99m sulfur colloid. It typically loses its radioactivity in less than 24 hours.

How is the procedure performed?

You will be asked to lie face up beneath or next to a gamma camera. When assessing lymph drainage to identify the sentinel lymph node, as in patients with melanoma, three to five injections of radiopharmaceutical are given into the skin surrounding the site of the melanoma. For breast cancer, the injections are given through the skin near the tumor or around the areola. All injections are made using a very small needle.

In lymphoscintigraphy performed for leg or arm edema, the radiopharmaceutical is injected into the skin between the first and second fingers or toes of each hand or foot.

Imaging begins immediately after injection and is repeated at five-minute intervals for 45 to 60 minutes. Often, both sides are studied so that the normal and abnormal sides can be compared. You may also be asked to exercise lightly for about 10 minutes, either by walking for leg exams or by doing handgrip or lifting exercises for arm exams. Images are acquired after exercise and, in some cases, delayed images are needed at one- to two-hour intervals for up to six hours, or even up to 24 hours.

For patients with breast cancer, images will be made of the underarm regions and breast/chest. For melanoma patients, images will be made of the underarms, head, neck and both groins. In most melanoma patients, imaging will take three to four hours. Markings are made on the skin to show where lymph nodes are located.

What will I experience during the procedure?

Lymphoscintigraphy is an outpatient procedure. No anesthesia is needed unless a lymph node biopsy is performed in the operating room immediately following lymphoscintigraphy in order to detect involvement by melanoma or breast cancer. It is important that you avoid moving while the images are recorded.

Most patients can resume regular activities immediately after the procedure. The small amount of radioactivity in your body will decrease due to the natural process of radioactive decay over several hours.

Who interprets the results and how do I get them?

Most patients undergo lymphoscintigraphy because their primary care physician or surgeon has recommended it. A radiologist, a physician who has specialized training in nuclear medicine and other medical imaging procedures, will interpret the images and forward a report to your physician.

What are the benefits vs. risks?

Benefits

The functional information provided by nuclear medicine examinations such as lymphoscintigraphy is unique and currently unattainable by using other imaging procedures. For many diseases, nuclear medicine studies yield the most useful information needed to make a diagnosis and to determine appropriate treatment, if any.

Sentinel lymph node biopsy following lymphoscintigraphy is a useful means of diagnosing and staging melanoma and learning whether the disease has spread from its primary site.

Lymphoscintigraphy and sentinel lymph node biopsy are less traumatic than the alternatives of staging breast cancer or melanoma by surgical lymph node dissections.

Computers are involved in the generation of images, making it possible to measure function and quantify it in addition to identifying abnormalities.
Because lymphoscintigraphy is generally performed according to standardized protocols, the type of examination done at one hospital is likely to be similar to that performed at other hospitals, making the information easy to understand and easy to transfer to all doctors who may be involved in your care.

Risks

Because the doses of radiopharmaceutical administered are small, nuclear medicine procedures such as lymphoscintigraphy result in minimal radiation exposure. Nuclear medicine has been used for more than five decades, and there are no known long-term adverse effects from such low-dose exposure.

As with all radiological procedures, it is important that you inform your physician and the radiological technologist if you are pregnant. In general, exposure to radiation during pregnancy should be kept to a minimum. Allergic reactions to radiopharmaceuticals may occur but are extremely rare.

Injection of the radiopharmaceutical may cause slight pain and redness.

What are the limitations of Lymphoscintigraphy?

Nuclear medicine procedures such as lymphoscintigraphy are time-consuming. They involve administration of a radiopharmaceutical, acquisition of images, and interpretation of the results. Imaging can take up to an hour and sometimes longer to perform.

This procedure is reviewed by a physician with expertise in the area presented and is further reviewed by committees from the American College of Radiology (ACR) and the Radiological Society of North America (RSNA), comprising physicians with expertise in several radiologic areas.

RadiologyInfo

http://www.radiologyinfo.org/en/info.cf ... pho&bhcp=1

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Additional Article and Studies

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Lymphoscintigraphy in Lymphedema Evaluation
How to achieve reliable results -


Introduction

Lymphostatic diseases (lymphedema) can be diagnosed with clinical methods. Imaging methods are only required in doubtful cases such as subclinical diseases, combination forms, early stages of edema or artificial lymphedema.

Quantitative lymphoscintigraphy is also described as a lymphoscintigraphic function test. It is a non-invasive, low risk, nuclear-medicine imaging method that is used primarily to assess dynamic processes in superficial and deep lymphatic areas of the upper and lower extremities.

Quantitative lymphoscintigraphy is considered the only functional test of the lymphatic system that provides accurate information about lymph transport in lymphedema patients.

Functional assessment of the peripheral lymphatic system is based on the time the radioactive substance requires for transport from the point of injection to the respective lymph node (arrival time in minutes) and the storage capacity of the regional lymph nodes (uptake in %)

Facts

In order to avoid misinterpretation and achieve highly reproducible data all parts of the examination should be standardized. Based on our experiences (1098 patients) using different protocols, reliable and comparable results can only be achieved by considering the following standards:

1.Evaluation using both static and dynamic examinations. The static part is based on individual total body images and is a part of the lymphoscintigraphic function test. It can provide important additional information but it is not sufficient for assessment of lymph transport function.

2.The dynamic examination lasting 60 minutes requires active physical exercise (treadmill, 25 watt) under standardized conditions because lymph flow is very slow in the resting patient. Additionally, insufficient exercise during the examination can lead to misinterpretation.

3.Attenuation correction (correction of reduced radioactive values caused by the thickness of tissue layer between the regional lymph nodes and skin surface) is essential when performing functional lymphoscintigraphy. Without it, unreliable results may ensue.

4.Single subcutaneous tracer injection.

5.Tracer: 99m-Tc-nanocolloid (in Germany)

6.Correction of physical decay of the radionucleotide

7.In addition standardization must include the volume injected, the amount of the injected radioactive material as well as the injection site.

Conclusion

1. Qualified diagnosis is not possible without standardization.

2. There is no doubt that the lymphoscintigraphic function test is a very useful diagnostic modality but its limitations should not be forgotten. For example, classification of findings is problematic following removal of axillary and inguino-pelvic lymph nodes. The usefulness of lymph node uptake values is limited in these circumstances.

3. It has been shown that systematic errors can be greatly reduced by using a developed, optimized protocol.

References:
W.J. Brauer, Lymphoscintigraphic function test: standardization versus nonstandardization. In E.Földi, M.Földi, M.H.Witte ed. Progress in Lymphology XIX, Lymphology 2004; 37 (Suppl):603-612

H. Weissleder, Quantitative Lymphoscintigraphy. In H. Weissleder, Ch. Schuchhardt ed. Lymphedema-Diagnosis and Therapy, Köln Viavital 2001:70-77
20.3.05
For further and more detailed information, physicians may contact: W.J. Brauer M.D.
E-Mail: wolfgang.brauer@gmx.net

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Evaluation of lymphoscintigraphic studies – Transport index versus region of interest technique

M. Weiss, R. Santos, RGH. Baumeister, LymphForsch 2005;9(2):78-84

Summary
The objective of this study was to discuss whether visual interpretation of lymphoscintigraphy combined with semi-quantitative evaluation by means of a numeric transport index is suitable to describe lymphatic function (baseline / follow-up studies of therapeutic procedures) or, whether region-of-interest-analysis of the lymph node uptake leads to a greater amount of relevant clinical information in daily routine. A total of 190 lymposcintigraphic investigations (n= 160 studies of patients presenting with peripheral lymphedema, n = 30 lymphoscintigraphies performed in Sprague-Dawley-rats) were included in the study.

For visual / semi-quantitative evaluation of lymphatic drainage in patients, a numerical index was used, as described before. This index is based on five visually assessed criteria: lymphatic kinetics, distribution pattern of the radiopharmaceutical, time to appearance at the lymph nodes, visualisation of lymph nodes and of lymph vessels.

Distribution of radioactivity was examined in Sprague-Dawley-rats by lymphoscintigraphy; the maxi-mum uptake (count-rate) of the whole body and in lymph nodes was analyzed by regions-of-interest technique. Additionally, for characterization of lymphatic and extra lymphatic tracer uptake an individ-ual relative count-rate ratio of the liver, lung, kidneys, and spleen has been calculated as described previously.

Lymphoscintigraphy is based on the physiological transport of radiotracers and permits the assess-ment of relative changes in lymphatic flow agent. Lymphoscintigraphy is an easily performed, reliable, and readily available method to assess lymphatic function. Our clinical results prove that lymphoscin-tigraphy combined with an evaluation by the numeric transport index as described, is well correlated to clinical findings and therefore provides sufficient information about lymph drainage in routine clini-cal diagnostics. Any additionally quantitative measurement of the lymph node uptake by means of re-gion-of-interest-technique has to be performed under absolute standardized conditions.

Key words: Lymphedema, Lymphoscintigraphy, Quantification
E-Mail: mayo.weiss@med.uni-muenchen.de

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Imaging of lymphatic vessels in breast cancer-related lymphedema: intradermal versus subcutaneous injection of 99mTc-immunoglobulin.

May 2006

O'Mahony S, Solanki CK, Barber RW, Mortimer PS, Purushotham AD, Peters AM.

Cambridge Breast Unit, Addenbrooke's Hospital, Cambridge, UK.

OBJECTIVE: The disordered physiology that results from axillary lymph node clearance surgery for breast cancer and that leads to breast cancer-related lymphedema is poorly understood. Rerouting of lymph around the axilla or through new pathways in the axilla may protect women from breast cancer-related lymphedema. The aim of the study was to compare intradermal with subcutaneous injection of technetium-99m ((99m)Tc)-labeled human polyclonal IgG (HIG) with respect to lymphatic vessel imaging.

MATERIALS AND METHODS: Six women with breast cancer-related lymphedema underwent unilateral upper limb lymphoscintigraphy, using a web space injection of (99m)Tc-labeled HIG, after intradermal and subcutaneous injections on separate occasions. Multiple sequential images were obtained of the affected upper limb and torso over 3 hr on each occasion. Accumulation of activity in blood was quantified from venous blood samples taken from the opposite arm.

RESULTS: Imaging after intradermal injection clearly showed discrete lymphatic vessels in five of six patients, in contrast to imaging after subcutaneous injection, which did not show any discrete vessels in any patient. Intradermal injection resulted in more rapid visualization of cutaneous lymph rerouting than subcutaneous injection in six of six patients. Recovery of injected (99m)Tc-labeled HIG in venous blood was greater after intradermal injection in six of six patients.

CONCLUSION: In patients with breast cancer-related lymphedema, lymphatic vessels are more clearly depicted after intradermal than subcutaneous injection as a result of direct access of radiotracer to dermal lymphatics. This finding has implications for imaging lymphatic vessel regeneration and lymph rerouting.

PMID: 16632730 [PubMed - in process]

http://www.ncbi.nlm.nih.gov/entrez/quer ... med_docsum

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Noncontrast three-dimensional magnetic resonance imaging vs lymphoscintigraphy in the evaluation of lymph circulation disorders: A comparative study.

Liu N, Wang C, Sun M.

Department of Plastic & Reconstructive Surgery, Shanghai9th People's Hospital, Shanghai Second Medical University, 639 Zhi Zao Ju Rd, Shanghai 200011, China. Liun2002@yahoo.com

BACKGROUND: Visualization of the lymphatic vessels is a challenge in patients with disorders of the lymphatic circulation. In an effort to improve the diagnostic scope of lymphatic imaging, we compared traditional lymphoscintigraphy (LSG) with three-dimensional magnetic resonance imaging (3D MRI). METHODS: From October 1, 2002, to May 30, 2004, 39 patients (27 males and 12 females) with lower extremity lymphedema and/or skin lymphorrhea in the abdominal wall or the external genitalia underwent LSG and 3D MRI. Patients' ages ranged from 3 to 71 years. Assessment of the imaging studies included the degree and quality of visualization of the malformations of the lymphatic collectors, lymphatic trunks, lymph nodes, and tissue edema.

RESULTS: In patients with lymphedema, chylous reflux syndrome, or both, LSG depicted the enlarged lymphatics and nodes as a fused band or mass. In 3D MRI, the dilated superficial lymphatic collectors and deep lymphatic trunks, as well as the accumulation of chyle and node enlargements, were clearly visualized. In patients with hypoplasia or aplasia of the lymphatics, LSG usually displayed the pattern of dermal backflow in the form of radiotracer filling of the dermal lymphatics or stagnation of the isotope at the injection point. The images obtained by 3D MRI were able to demonstrate the extent of tissue fluid accumulation and distinguish edema fluid from subcutaneous fat.

CONCLUSIONS: In patients with peripheral and central lymphatic malformations, LSG provided images representative of the function of the lymphatic vessels but failed to give detailed information regarding its anatomy. 3D MRI provided extensive information on the anatomy of the lymph stagnated vasculature as well as on the effects of lymphatic dysfunction on local structures and tissue composition.

PMID: 15696047 [PubMed - indexed for MEDLINE]

http://www.ncbi.nlm.nih.gov/entrez/quer ... med_docsum
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