Current use of lymphography for staging lymphomas and genital tumors

Imaging the urologic patient: the utility of intravenous pyelogram in the CT scan era

PURPOSE

An opportunity exists to evaluate the quality of care in patients undergoing intravenous pyelogram (IVP) imaging and to define the role of IVP in the computed tomography scan era.

METHODS

Medical records were reviewed for patient demographics, inpatient versus outpatient setting, indication for IVP, physician/specialty who ordered IVP, and the need for subsequent imaging within a 30-day period in patients who underwent IVP from October 2007 to December 2011. Chi-square test was used to compare the number of additional radiologic examinations ordered within 30 days of the initial IVP across the different specialties ordering IVPs.

RESULTS

Six hundred and eighty patients underwent IVP imaging during the study period. The primary reason to order an IVP was the evaluation of urolithiasis/flank pain (50%), followed by urologic evaluation after surgery (23%). Three hundred and twenty-five patients (48%) subsequently had an additional 547 radiologic studies within 30 days of the IVP to further evaluate their condition. Of the 325 patients undergoing additional imaging studies, 36% had differing or additional diagnostic information noted that could change medical decision-making.

CONCLUSIONS

Inferior imaging of the urologic patient by IVP leads to the acquisition of additional imaging studies to render a diagnosis. IVP has a limited clinical role, and thus, its use should be strictly limited to highly select cases.

Wertigkeit der Bildgebung für die Lymphknotenmetastasierung beim Nierenzell-, Blasen-, Prostata- und Peniskarzinom sowie dem Hodentumor

Computed tomography (CT) imaging is the standard method for the assessment of lymph node metastases in renal cell and testicular cancer. In bladder cancer and prostate cancer the results of CT are not convincing due to a large number of false-negative findings and the prognostic relevance of undetected metastases. For both entities recent studies revealed that MR lymphography using iron oxide particles allows the detection of small metastatic lymph nodes. For penile cancer reliable results for imaging of lymph node metastases do not exist. PET imaging using [(18)F]-fluorodeoxyglucose (FDG) is the modality of choice in therapy control of seminomas but has no defined value in other urological malignancies. PET with [(11)C] choline and [(11)C] acetate offers great potential in staging and restaging of prostate cancer. Further investigations are necessary to determine the role of these new methods.

Lymphography: An Old Technique Retains Its Usefulness

Conventional lymphography has long been the method of choice for imaging the lymphatic system. However, the number of lymphographic studies performed in oncology centers has declined markedly since the introduction of cross-sectional imaging techniques, especially computed tomography (CT). Therefore, levels of expertise in both performing lymphography and interpreting lymphograms are falling. The unique ability of lymphography to demonstrate derangements of the internal architecture of normal-sized lymph nodes can be valuable and makes it more accurate than CT in evaluation of some lymphomas (especially Hodgkin disease) and genitourinary malignancies. In fact, lymphography and CT are complementary rather than mutually exclusive techniques for the staging of some lymphomas and genitourinary malignancies. In addition, lymphography opacifies the lymphatic channels and therefore may be a valuable tool for detection of lymphatic fistulas or lymphatic leakage. Finally, lymphography helps guide subsequent therapy in patients with lymphomas, genitourinary malignancies, or disorders of lymphatic flow.

Is it wise to eliminate lymphography from the staging of Hodgkin's disease?

We believe that lymphography and CT are complementary rather than mutually exclusive techniques for the diagnosis and staging of HD. Unfortunately, it seems that many radiologists and clinicians disregard the ability of lymphography to provide qualitative information on lymph node architecture, which is not available by CT. The use of lymphography is declining in several teaching centers throughout the world. This makes it difficult for young radiologists to acquire the skills needed to perform and interpret lymphographies successfully. In turn, radiologists who have little experience with lymphography are less likely to use the technique. Because most of the treatment-related morbidity in HD is dose-related, and because lymphography helps to avoid over- and undertreatment, we believe that high-quality lymphography continues to have a significant role in the staging of selected HD patients. Moreover. lymphography may reduce both the cost of management and the morbidity rate in many HD patients. One solution would be to continue to use lymphography in a small number of institutions specialized in the management of HD.

Indirect computed tomography lymphography of subdiaphragmatic lymph nodes using iodinated nanoparticles in normal dogs

RATIONALE AND OBJECTIVES

We evaluated the imaging characteristics of an iodinated particulate contrast agent for indirect computed tomography (CT) lymphography of normal subdiaphragmatic lymph nodes in dogs.

METHODS

Four milliliters of a 15% (wt/vol) iodinated nanoparticle suspension was injected into the gastric, colonic, rectal, or cervical submucosa, loose paraprostatic fascia, or metatarsal subcutaneous tissues in 10 healthy beagles. Endoscopic, CT, or ultrasound guidance was used when necessary to facilitate contrast agent delivery. CT and radiographic images were obtained prior to contrast administration and at 4 hr, 24 hr, and 7 days postcontrast injection. Postmortem examinations were then conducted.

RESULTS

CT images showed enhancement of regional lymph nodes draining the various injection sites. The mean attenuation of opacified nodes was 678 +/- 463 Hounsfield units 24 hr after injection and remained elevated 7 days later. Lymph node opacification on CT images correlated well with the node location observed on postmortem examinations.

CONCLUSION

Subdiaphragmatic lymph nodes can be effectively opacified using an iodinated nanoparticle contrast agent for indirect CT lymphography.

Has lymphography a role in early stage testicular germ cell tumours?

A retrospective study was performed of 183 newly diagnosed seminoma cases and 73 newly diagnosed non-seminomatous germ cell tumours (NSGCT) presenting from 1985 to 1989 to a tertiary referral cancer hospital. The purpose was to assess the contribution of bipedal lymphography (LG) to the management of these patients. As the main value of LG is in detecting small retroperitoneal lymph node (LN) metastases, analysis concentrated upon early stage disease, specifically N0 and N1a LN disease. Comparison between LG results, abdominopelvic computed tomography (APCT), final clinical stage and treatment outcome was performed. We found that with the LG and APCT criteria used (filling defects > 2 mm and LN diameter > 20 mm, respectively), LG was much more sensitive in disease detection. However, with modern techniques APCT can reliably detect disease 10 mm or greater. In addition, tumour marker status, primary tumour vascular invasion status and initial clinical examination were each more important in staging NSGCT disease than LG alone. Thus, LG is now rarely used in our institution but we will have to monitor our excellent survival data to confirm that this change in policy is warranted.

Iodinated nanoparticles for indirect computed tomography lymphography of the craniocervical and thoracic lymph nodes in normal dogs

RATIONALE AND OBJECTIVES

We evaluated the imaging characteristics of an interstitially or intraperitoneally delivered iodinated particulate contrast agent for computed tomography (CT) lymphography of the craniocervical and thoracic lymph nodes.

METHODS

We injected 2-4 ml of 15% wt/vol iodinated nanoparticle suspension subcutaneously, submucosally, or intraperitoneally in eight normal dogs. CT and plain radiographic images were obtained prior to contrast administration and 4 hr, 24 hr, and 7 days after injection. Correlation was made to detailed postmortem assessment.

RESULTS

CT images showed enhancement of regional nodes draining injection sites. Mean attenuation of opacified nodes was 313 +/- 297 (mean +/- standard deviation), 536 +/- 453, and 492 +/- 372 Hounsfield units at 4 hr, 24 hr, and 7 days postinjection, respectively. Lymph node opacification on CT images correlated well with node location found at postmortem.

CONCLUSION

Craniocervical and thoracic lymph nodes can be effectively opacified from interstitial or intraperitoneal delivery of this iodinated nanoparticulate contrast agent.

Role of bipedal lymphangiogram in radiation treatment planning for cervix cancer

PURPOSE

The role of bipedal lymphangiogram in tailoring radiation portals in radical radiation therapy for Stages II or III cervix cancer is investigated.

METHODS AND MATERIALS

The records and simulation films of 87 patients with Stage II or III carcinoma of the cervix treated with radical radiation therapy alone have been retrospectively reviewed.

RESULTS

Sixty-two percent of patients who had a bipedal lymphangiogram, subsequently had their radiation fields altered from a "standard portal." The most frequently altered fields were the lateral margin of the postero anterior field and the anterior margin of the lateral fields. In order to cover the lymphatic channels in the pelvis in 90% of cases as outlined by the bipedal lymphangiogram, the lateral margins of the postero anterior fields would need to be 2.5 cm lateral to the pelvic brim and the anterior border of the lateral field, 0.5 cm anterior to the pubic symphysis.

CONCLUSION

"Standard" fields adequately cover the median distribution of lymphatics, but may result in a geographic miss in some patients. Bipedal lymphangiograms allow a more accurate tailoring of pelvic lymphatic fields.