3-Dimensional Computed Tomography Lymphography–Guided Identification of Sentinel Lymph Nodes in Breast Cancer Patients Using Subcutaneous Injection of Nonionic Contrast Medium

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 et al. 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.

Computerized evaluation scheme to detect metastasis in sentinel lymph nodes using contrast-enhanced computed tomography before breast cancer surgery

Sentinel lymph node (SLN) biopsy for evaluating lymph node metastasis during breast cancer surgery is associated with several problems, such as the consequent increase in operation time and the possibility of abrupt changes in the treatment plan during the operation. Although it is desirable to distinguish SLNs with and without cancer metastasis before surgery, there is no established examination for this purpose. This study aimed to develop a computerized scheme for evaluating metastasis in SLNs by analyzing computed tomography lymphography images and the three-dimensional versions of these images. Our database consisted of computed tomography lymphography images from 100 patients with breast cancer. Three subjective features of the nodes were assessed in the three-dimensional images: (1) the shape of the lymphoduct, (2) degree of signal enhancement in the nodes, and (3) shape of the nodes. Six objective features were also assessed in the computed tomography lymphography images: (4) the long axis, (5) area, (6) standard deviation of the signal values, (7) mean signal values, (8) maximum signal value, and (9) minimum signal value. Support vector machines were employed to evaluate cancer metastasis in SLNs. For the input, six of the nine features were selected in a stepwise method. The classification accuracy, sensitivity, and specificity were 98.0% (98/100), 97.8% (44/45), and 98.2% (54/55), respectively. The positive and negative predictive values were 97.8% (44/45) and 98.2% (54/55), respectively. This computerized method exhibited high classification accuracy and will be useful in determining the need for lymph node dissection before breast cancer surgery.

Superparamagnetic iron oxide-enhanced MRI at 3 T for accurate axillary staging in breast cancer

BACKGROUND

The aim of this study was to evaluate whether MRI at 3 T with superparamagnetic iron oxide (SPIO) enhancement is an accurate and useful method for detecting metastases in sentinel nodes identified by CT-lymphography (CT-LG) in patients with breast cancer. The results were compared with those obtained using CT-LG alone and diagnosing metastasis according to size criteria.

METHODS

Patients with clinically node-negative breast cancer were included. Sentinel nodes identified by CT-LG were evaluated prospectively using SPIO-enhanced MRI at 3 T. Sentinel node size was measured on CT-LG, and a node larger than 5 mm in short-axis diameter was considered metastatic. Sentinel nodes localized by CT-LG were removed, and imaging results and histopathological findings were compared.

RESULTS

Sentinel nodes were identified successfully by CT-LG in 69 (99 per cent) of 70 patients. All 19 patients with a finding of metastasis in sentinel nodes at pathology were also shown to have metastases on MRI. Forty-eight of 50 patients with non-metastatic sentinel nodes diagnosed at pathology were classified as having non-metastatic nodes on MRI. On a patient-by-patient basis, the sensitivity, specificity and accuracy of MRI for the diagnosis of sentinel node metastases were 100, 96 and 97 per cent; respective values for CT-LG were 79, 56 and 62 per cent. The specificity and accuracy of MRI were superior to those of CT-LG (P < 0·001 and P = 0·002 respectively).

CONCLUSION

SPIO-enhanced MRI at 3 T is useful for accurate diagnosis of metastatic sentinel nodes, indicating that sentinel node biopsy may be avoided in patients with breast cancer who have non-metastatic sentinel nodes on imaging.

Real-time lymphography by indocyanine green fluorescence: improved navigation for regional lymph node staging

OBJECTIVES

Lymphatic imaging is an important step for the identification of lymphonodal positive disease in solid malignancies. Various methods have been established to detect positive lymph nodes, but the available diagnostic tools leave some inherent drawbacks. The aim of this study was to validate the indocyanine green (ICG) guided approach for transcutaneous and transmesenterial navigation with accurate lymph vessel and node identification for regional lymph node staging in solid malignancies.

METHODS

After institutional review board approval, a planar fluorescence imaging system was applied for lymphography and lymph node detection using ICG. A total of 96 patients were recruited and subject to fluorescence navigation for axillary (n = 46), inguinal (n = 16), and mesenterial (n = 34) visualization to analyze technical and clinical feasibility of the method after regional lymph node dissection and the applicability.

RESULTS

Overall fluorescence imaging identified lymphatic vessels and the SLN in 92 out of 96 patients (detection rate: 96%) after a mean injection of 7 mg ICG. Sensitivity based on fluorescent emission of ICG navigation was 95.6% in 65 out of 68 patients with lymph node dissection. All solid tumors were feasible for fluorescence-guided navigation with a broad spectrum.

CONCLUSION

Fluorescence-guided real-time lymphography with navigation to regional lymph nodes enables accurate visualization for a broad spectrum of different solid tumors with potential lymphonodal spread. In addition, the technique can be applied for lymphography in non-malignant diseases. With reference to the broad application spectrum, institutional investment in camera equipment can be justified.

Breast sentinel lymph node navigation with three-dimensional computed tomography-lymphography: a 12-year study

PURPOSE

To evaluate the utility of three-dimensional (3D) computed tomography (CT)-lymphography (LG) breast sentinel lymph node navigation in our institute.

PATIENTS AND METHODS

Between 2002 and 2013, we preoperatively identified sentinel lymph nodes (SLNs) in 576 clinically node-negative breast cancer patients with T1 and T2 breast cancer using 3D CT-LG method. SLN biopsy (SLNB) was performed in 557 of 576 patients using both the images of 3D CT-LG for guidance and the blue dye method.

RESULTS

Using 3D CT-LG, SLNs were visualized in 569 (99%) of 576 patients. Of 569 patients, both lymphatic draining ducts and SLNs from the peritumoral and periareolar areas were visualized in 549 (96%) patients. Only SLNs without lymphatic draining ducts were visualized in 20 patients. Drainage lymphatic pathways visualized with 3D CT-LG (549 cases) were classified into four patterns: single route/single SLN (355 cases, 65%), multiple routes/single SLN (59 cases, 11%) single route/multiple SLNs (62 cases, 11%) and multiple routes/multiple SLNs (73 cases, 13%). SLNs were detected in 556 (99.8%) of 557 patients during SLNB.

CONCLUSION

CT-LG is useful for preoperative visualization of SLNs and breast lymphatic draining routes. This preoperative method should contribute greatly to the easy detection of SLNs during SLNB.

Sentinel node mapping of VX2 carcinoma in rabbit thigh with CT lymphography using ethiodized oil

OBJECTIVE

To assess the feasibility of computed tomography (CT) lymphography using ethiodized oil for sentinel node mapping in experimentally induced VX2 carcinoma in the rabbit thigh.

MATERIALS AND METHODS

This experiment received approval from the institutional animal use and care administrative advisory committee. Twenty-three rabbits with VX2 carcinoma in the thigh underwent CT before and after (1 hour, 2 hour) peritumoral injection of 2 mL ethiodized oil. After the CT examination, sentinel nodes were identified by peritumoral injection of methylene blue and subsequently removed. The retrieved sentinel and non-sentinel lymph nodes were investigated with radiographic and pathologic examinations. Based on the comparison of CT findings with those of radiographic and pathologic examinations, the diagnostic performance of CT for sentinel node identification was assessed.

RESULTS

All 23 rabbits showed 53 ethiodized oil retention nodes on post-injection CT and specimen radiography, and 52 methylene blue-stained nodes at the right femoroiliac area. Of the 52 blue-stained sentinel nodes, 50 nodes demonstrated ethiodized oil retention. Thus, the sentinel node detection rate of CT was 96% (50 of 52). On pathologic examination, 28 sentinel nodes in 17 rabbits (nodes/rabbit, mean ± standard deviation, 1.7 ± 0.6) harbored metastasis. Twenty seven of the 28 metastatic sentinel nodes were found to have ethiodized oil retention.

CONCLUSION

Computed tomography lymphography using ethiodized oil may be feasible for sentinel node mapping in experimentally induced VX2 carcinoma in the rabbit thigh.

MR lymphangiography with intradermal gadofosveset and human serum albumin in mice and primates

PURPOSE

To investigate MR lymphangiography in mice and primates with intradermal Gadofosveset and human serum albumin. Gadofosveset is a US FDA approved small molecule Gadolinium (Gd) chelate (957 Da) which reversibly binds serum albumin and temporally behaves as a macromolecule. As the structure of albumin varies among species, the affinity of Gadofosveset is optimized for human albumin. In this study, Gadofosveset premixed with 10% human serum albumin (HSA) was injected intradermally in mice and monkeys, and then MR lymphangiography was performed on a 3.0 Tesla clinical scanner.

MATERIALS AND METHODS

Twenty microliters of each agent was injected intradermally at both sides of the front and back paws using a 30-gauge needle into female athymic nude mice (6-8 weeks old, n = 3 mice in each group). The performance of Gadofosveset-HSA was compared with Gd-labeled dendrimers (G4: 6 nm, G6: 10 nm) or Gd-DTPA. The target-to-muscle ratio (TMR = target signal intensity (SI)/muscle SI) was calculated at each time point. The TMRs were compared with a one-way analysis of variance followed by a Bonferroni multiple comparison test.

RESULTS

Images taken as early as 2.5 min after intradermal (id) injection depicted enhanced lymph nodes using Gadofosveset-HSA (2.41 ± 0.20). Up to 7.5 min after injection, TMRs of Gadofosveset-HSA were greater than those of dendrimers (G4 or G6-Gd-DTPA: 2.24 ± 0.10, 2.12 ± 0.11, respectively). By 15 min postinjection, TMRs of Gadofosveset-HSA (2.18 ± 0.19) were comparable to Gd-labeled dendrimers (G4-Gd-DTPA: 2.37 ± 0.15, G6-Gd-DTPA: 2.25 ± 0.18). Gadofosveset-HSA and Gd labeled dendrimers resulted in satisfactory MR lymphography in mice and monkeys.

CONCLUSION

Because both Gadofosveset and HSA are approved for human use and Gadofosveset clears rapidly through the kidneys, this method has advantages over Gd-dendrimers and could be used for visualizing lymphatic drainage and detecting lymph nodes.

Early gastric cancer: feasibility of CT lymphography with ethiodized oil for sentinel node mapping

PURPOSE

To evaluate the feasibility of CT lymphography with ethiodized oil for sentinel node mapping in porcine stomachs and in patients with early gastric cancer.

MATERIALS AND METHODS

Approval for the animal study was obtained from the authors' institutional animal use and care administrative advisory committee, the clinical study was approved by the institutional review board, and informed consent was obtained from each participant. Five pigs underwent CT lymphography 1 hour after gastric subserosal injection of 1 mL ethiodized oil and sentinel node mapping with injection of 1 mL methylene blue. Ethiodized oil retention nodes were identified on the radiographic images of the gastric specimen and removed for histopathologic examination. In addition, 10 patients with early gastric cancer underwent CT lymphography with peritumoral injection of 1 mL ethiodized oil, followed by sentinel basin extirpation with CT and routine nodal dissection. The removed sentinel basins were examined by radiography. Histopathologic examination was performed for dissected nodes, including sentinel nodes.

RESULTS

In each of the five pigs, CT showed one perigastric ethiodized oil retention node. After harvesting the ethiodized oil retention node, blue-stained areas were identified in the five removed nodes and intranodal ethiodized oil was detected on histopathologic examination. In all 10 patients, CT lymphography with ethiodized oil successfully defined the sentinel basin with ethiodized oil retention nodes. CT lymphography revealed 20 ethiodized oil retention nodes. After basin extirpation, 28 and 46 nodes were detected on radiographic and histopathologic examinations. Histopathologic examination revealed that one patient had micrometastases at two sentinel nodes and another patient had isolated tumor cells at one sentinel node. No patient had metastasis in nonsentinel nodes.

CONCLUSION

CT lymphography with ethiodized oil may be a feasible method for sentinel node mapping in patients with early gastric cancer.

High rate of solitary sentinel node metastases identification by fluorescence-guided lymphatic imaging in breast cancer

BACKGROUND

The lymph node status was shown to be an important prognostic factor for breast cancer, but controversial issues remain. There has been increased focus on optimizing the visualization of lymph nodes for an accurate and selective approach to axillary lymph nodes. Fluorescence-guided lymphatic imaging is a potential candidate for further research on remaining controversies.

METHODS

Forty-seven patients were subject to injection of indocyanine green for navigation to the SLN based on fluorescent dye retention detection. In two groups, patients either received intended axillary lymph node dissection (ALND) and sentinel lymph node biopsy (SLNB) for superstaging or isolated SLNB for minimal-invasive staging. The prospective study was designed to evaluate the technical feasibility with focus on solitary positive SLN.

RESULTS

Visualization of lymphatic vessels with bright fluorescence of the SLN was feasible in 46 of 47 patients. Eighteen of 19 nodal positive patients were correctly identified with a sensitivity of 94.7% in all patients after ALND. After immunohistochemistry, in 19 of 25 overall nodal positive patients (76%) the SLN was the only positive lymph node.

CONCLUSION

Fluorescence-guided imaging using fluorescence retention detection allows transcutaneous navigation with a high rate of solitary positive SLN identification as an alternative technique for further research.

Nanoparticles in sentinel lymph node mapping

The lymph nodes and lymphatic vessels are more difficult to access than most vascular structures. Interstitial injection of imaging agents is often necessary to opacify the lymphatics. Traditionally, radionuclide methods of sentinel node imaging have dominated this field, however, limitations in resolution and exposure to radiation have encouraged the development of newer imaging methods. Among these are magnetic resonance lymphography in which a Gadolinium labeled nanoparticle is injected and imaged providing superior anatomic resolution and assessment of lymphatic dynamics. Optical imaging employing various nanoparticles including quantum dots also provide the capability of mapping each lymphatic basin in another "color". Taken together this "toolbox" of lymphatic imaging agents is poised to improve our understanding of the lymphatic system.

Misoperation of CT automatic tube current modulation systems with inappropriate patient centering: phantom studies

OBJECTIVE

Inappropriate patient centering on the gantry changes the size of the localizer radiographs used for CT examinations, influencing the operation of CT automatic tube current modulation because tube current is controlled with information from localizer radiographs. The purpose of this study was to examine the influence of inappropriate patient centering on the gantry isocenter on automatic tube current modulation.

MATERIALS AND METHODS

An elliptical phantom was scanned with four automatic tube current modulation techniques after acquisition of localizer radiographs in the horizontal and vertical directions with the phantom center shifted from the gantry isocenter in the vertical direction. After scanning, the magnification rate of the frontal localizer radiographs, tube current-time product, and image noise were examined.

RESULTS

On phantom studies, the magnification rate of localizer radiographs showed a linear relation to the vertical deviation of the phantom from the gantry isocenter. From 50 mm above to 50 mm below the gantry isocenter, tube current-time products ranged from 75% to 141% compared with those at the gantry isocenter. In addition, increases and decreases in the amount of image noise related to changes in tube current-time product were confirmed.

CONCLUSION

Inappropriate patient centering causes misoperation of automatic tube current modulation systems, in which tube current is controlled with information from localizer radiographs, and thus causes increases in tube current or image noise.

Evaluation of breast lymphatic pathways with indocyanine green fluorescence imaging in patients with breast cancer

BACKGROUND

In patients with early breast cancer, sentinel lymph node biopsy (SLNB) has been emerging as a new standard of care. The use of SLNB with a blue dye is convenient and safe, but it requires a high level of technical skill. Recently, an instrument that can provide fluorescence imaging of lymphatic flow has been introduced. In the present study, we analyzed breast lymphatic pathways and discussed its potential as a modality to complement the use of SLNB with a blue dye.

METHODS

Thirty-seven consecutive patients with breast cancer were examined. To obtain fluorescence imaging, an invisible near-infrared fluorescence imaging system was used. After indocyanine green was subdermally injected in the subareolar site and at two sites around the tumor, the subcutaneous lymphatic drainage pathway (LDP) was observed.

RESULTS

In 27 (72.9%) of the patients, the number of LDP from the periareolar area was one or two. In 21(63.6%) of 33 patients with subdermal injection around the tumor, no LDP was observed from the peritumoral area. Lymphatic connection between the peritumoral area and the periareolar area was observed very frequently (91.7%). In 26 (70.3%) of the patients, multiple routes joined together and only one route was ultimately directed to the axilla. Significant correlation was seen between body mass index (BMI) and the transit time to the axilla after injection (p = 0.0038). Additionally, a significant correlation was seen between the number of LPD from the periareolar area and the distance between detected SLNs and the fluorescence line-disappearing point (p = 0.034).

CONCLUSIONS

This instrument can provide some important information, and can be an available and reliable navigator for SLNB with a blue dye.

Clinical efficacy and problems with CT lymphography in identifying the sentinel node in breast cancer

BACKGROUND

Combining a radioisotope with a dye-guided method is the best method for identification of the sentinel lymph nodes (SNs) in breast cancer. However, some institutions are limited to use of a dye-guided method alone. Recently, computed tomographic lymphography (CTLG) employing a nonionic contrast medium has achieved SN identification.

PATIENTS AND METHODS

218 patients with primary breast cancer and no clinical evidence of lymph node metastasis were studied. SN identification was performed by CTLG and a dye-guided method. The SN identification rate was analyzed for correlations with the clinicopathological findings.

RESULTS

The SN identification rates were 96% with CTLG, 92% with the dye-guided method and 99% with both methods combined. The identification rates with CTLG and the combined method were significantly lower in node-positive patients compared to node-negative patients, and significantly lower with the combined method in vascular invasion-positive patients compared to negative patients. In addition, the SN identification rate with the dye-guided method was significantly lower in patients with a body mass index (BMI) of > or = 25, whereas the BMI did not affect the identification rate with CTLG or the combined method. Multiple SNs were detected in approximately 20% of the patients.

CONCLUSION

Combined performance of CTLG and a dye-guided method enables identification of SNs prior to breast cancer surgery. That SN identification is easier compared with by the dye-guided method alone, and the identification rate is improved compared with either method alone. The combination of methods was especially useful in obese patients. For patients with multiple SNs, the combination has the further advantage of enabling accurate SN biopsy. CTLG may yield false-negative findings in node-positive patients and patients with lymph vessel obstruction.

Evaluation of sentinel lymph node metastasis alone guided by three-dimensional computed tomographic lymphography in video-assisted breast surgery

BACKGROUND

Detailed relations between lymph nodes and lymph flow can be clarified by three-dimensional computed tomographic (3D-CT) lymphangiography. Systematic collection of lymph nodes based on 3D-CT lymphangiography can decrease unnecessary lymph node dissection and attendant complications.

METHODS

To mark the sentinel lymph node (SLN) on the skin, 3D-CT lymphangiography was performed the day before the surgery. Iopamiron 300 (2 ml) was injected subcutaneously. A 16-channel multidetector-row helical CT scan image was reconstructed to produce a 3D image of lymph ducts and lymph nodes. Biopsy of SLN was performed by a dye-staining method using Visiport-aided endoscopy. Stained lymph nodes were located by following the dye in the lymph ducts on a video monitor. For SLN-metastasis-positive patients, standard axillary lymph node dissection (levels 1 and 2) was performed with video assistance.

RESULTS

Since December 2001, video-assisted breast surgery has been performed for 180 patients, SLN biopsy for 150 patients, and 3D-CT lymphangiography for 110 patients. Findings show that SLN-positive metastasis (n = 31) was accompanied by SLN metastasis alone in 14 patients. One-node metastasis, except for SLN, was observed in seven patients, two-node metastasis in three patients, and metastasis involving more than three nodes in seven patients. Review of the lymphoid path using 3D-CT lymphangiography confirmed that metastasis occurred in order of lymph flow.

CONCLUSIONS

Absence of metastasis in the second and third SLNs, even in patients with SLN metastasis, obviates the need for dissection of more nodes.

Impact of Operator-Selected Image Noise Index and Reconstruction Slice Thickness on Patient Radiation Dose in 64-MDCT

OBJECTIVE

Our objective was to develop a better understanding of the complex interrelationship between image noise, reconstruction slice thickness, and patient radiation dose on a 64-MDCT scanner that uses automated tube current modulation.

MATERIALS AND METHODS

We reviewed physics theory and performed phantom dose measurements on a 64-MDCT scanner while altering operator-selectable image noise and reconstruction slice thickness.

RESULTS

Using phantom dose measurements to adjust theoretic predictions, we constructed both a spreadsheet and a graph that visually display the interrelationships between operator-selected image noise and reconstruction slice thickness and the resulting patient dose.

CONCLUSION

This table and graph may help operators understand the trade-offs when prospectively trying to minimize dose and optimize image noise for selected reconstruction slice thicknesses on this type of 64-MDCT scanner.

Video-assisted breast surgery and sentinel lymph node biopsy guided by three-dimensional computed tomographic lymphography

BACKGROUND

Video-assisted breast surgery (VABS) is a less invasive and aesthetically better option for benign and malignant breast diseases and for sentinel lymph node biopsy (SLNB). The authors have performed 150 VABS procedures since December 2001. They have examined the usefulness of three-dimensional computed tomographic (3D-CT) lymphography for detecting sentinel lymph nodes (SLNs) precisely, as well as the cosmetic and treatment results of VABS.

METHODS

In this study, VABS was performed with a 2.5-cm skin incision in the axilla or periareola (1 cm in the axilla for SLNB), using a retraction method, for mammary gland resection, SLNB, axillary lymph node dissection, and breast reconstruction under video assistance. On the day before the surgery, 3D-CT lymphography was performed to mark SLN on the skin. Above the tumor and near the areola, 2 ml of Iopamiron 300 was injected subcutaneously. A 16-channnel multidetector-row helical CT scan image was taken after 1 min and reconstructed to produce a 3D image. Sentinel lymph node biopsy was performed by the VABS technique using the Visiport.

RESULTS

The VABS procedure was performed for 19 benign and 131 malignant diseases, and 115 SLNBs (74 with 3D-CT) were performed. The SLNs were shown precisely by 3D-CT lymphography, as proved by a case of lymph node metastasis, in which accurate relationships between lymph ducts and SLNs were shown. These were classified into four patterns: a single duct to single node (40 cases), multiple ducts to a single node (13 cases), a single duct to multiple nodes (1 case), and multiple ducts to multiple nodes (12 cases). The SLNB procedure can be performed safely by 3D-CT lymphography and less invasively by VABS.

CONCLUSIONS

The findings show that 3D-CT lymphography is useful for performing precise SLNB using VABS.

Imaging of the lymphatic system: new horizons

The lymphatic system is a complex network of lymph vessels, lymphatic organs and lymph nodes. Traditionally, imaging of the lymphatic system has been based on conventional imaging methods like computed tomography (CT) and magnetic resonance imaging (MRI), whereby enlargement of lymph nodes is considered the primary diagnostic criterion for disease. This is particularly true in oncology, where nodal enlargement can be indicative of nodal metastases or lymphoma. CT and MRI on their own are, however, anatomical imaging methods. Newer imaging methods such as positron emission tomography (PET), dynamic contrast-enhanced MRI (DCE-MRI) and color Doppler ultrasound (CDUS) provide a functional assessment of node status. None of these techniques is capable of detecting flow within the lymphatics and, thus, several intra-lymphatic imaging methods have been developed. Direct lymphangiography is an all-but-extinct method of visualizing the lymphatic drainage from an extremity using oil-based iodine contrast agents. More recently, interstitially injected intra-lymphatic imaging, such as lymphoscintigraphy, has been used for lymphedema assessment and sentinel node detection. Nevertheless, radionuclide-based imaging has the disadvantage of poor resolution. This has lead to the development of novel systemic and interstitial imaging techniques which are minimally invasive and have the potential to provide both structural and functional information; this is a particular advantage for cancer imaging, where anatomical depiction alone often provides insufficient information. At present the respective role each modality plays remains to be determined. Indeed, multi-modal imaging may be more appropriate for certain lymphatic disorders. The field of lymphatic imaging is ever evolving, and technological advances, combined with the development of new contrast agents, continue to improve diagnostic accuracy.

Endoscopic video-assisted breast surgery: procedures and short-term results

BACKGROUND

We devised a new endoscopic operation for breast diseases. We report the aesthetic and treatment results of this procedure.

METHODS

A 2.5-cm axillary skin incision was made for a single approaching port, and a working space was created by retraction. Under video assistance, we resected the mammary gland partially or totally, and in the case of malignant diseases we also performed a sentinel lymph node biopsy and dissected axillary lymph nodes (levels I and II).

RESULTS

From December 2001 through April 2005, we performed endoscopic video-assisted breast surgery (VABS) in 100 patients with breast diseases. The diseases were benign in 18 patients and malignant in 82 patients. Of the malignant diseases, 80 underwent breast-conserving surgery and 2 underwent skin-sparing mastectomy. There was no significant difference in operation time, blood loss, or blood examinations related with the acute phase reaction between VABS and conventional breast-conserving procedures. All surgical margins were negative on examination of permanent histological preparations. The wounds healed without noticeable scarring. The original shapes of the breast were preserved. All patients expressed their great satisfaction with VABS.

CONCLUSIONS

VABS can be considered as a surgical option and can provide aesthetic advantages for patients with breast disease.

Early breast cancer

Breast cancer remains a common disease throughout the world. Here we review new knowledge about early breast cancer obtained during the past 5 years. The prognosis of early breast cancer is generally favorable. Especially, ductal carcinoma in situ has been regarded as a non-life-threatening disease. Therefore, early diagnosis and early onset of the treatment has been important. Early age at menarche, late age at first birth, and late age at menopause are related to breast cancer risk. Examination by mammography and ultrasonography is still the most effective means of detection for premenopausal and postmenopausal women, respectively. Additionally, there have been important advances in MRI, sentinel lymph node biopsy, breast-conserving surgery, partial breast irradiation, neoadjuvant systemic therapy, and adjuvant systemic therapy. Another approach to keeping the disease under control is the elucidation of breast cancer's molecular biological features. Assessment of potential molecular targets can lead to early diagnosis and molecular targeted treatment.

Radiation Dose Associated with Unenhanced CT for Suspected Renal Colic: Impact of Repetitive Studies

OBJECTIVE

The purpose of our study was to assess the dose of ionizing radiation delivered through the use of unenhanced CT for suspected renal colic by determining the incidence of repeated unenhanced CT examinations and the cumulative radiation dose delivered.

MATERIALS AND METHODS

All unenhanced CT examinations for suspected renal colic performed at our institution over a 6-year period were included, and patient age, sex, and multiplicity of examinations were determined. For the adult patient, this protocol prescribes a fixed tube current of 200 mA, 140 kVp, and a nominal slice width of 5 mm. The dose-length product (DLP) was estimated for 15 randomly chosen single-detector CT (SDCT) and MDCT adult flank pain examinations using manufacturer's software. The mean DLPs for SDCT and MDCT were computed and converted to effective doses. Total effective doses were calculated for patients who underwent more than three examinations, and values were compared with established standards.

RESULTS

A total of 5,564 examinations were performed on 4,562 patients. Of these patients, 2,795 (61%) were women (mean age, 45.5 +/- 16.2 [SD] years) and 1,731 (38%) were men (mean age, 44.7 +/- 16.4 years), with 144 patients (3%) of pediatric age. The mean effective doses for a single study were 6.5 mSv for SDCT and 8.5 mSv for MDCT. A subset of 176 patients (4%) had three or more examinations, with estimated effective doses ranging from 19.5 to 153.7 mSv. All patients with multiple examinations had a known history of nephrolithiasis.

CONCLUSION

Patients with a history of nephrolithiasis and flank pain are at increased risk for serial CT with potentially high cumulative effective doses.

Delivery of gadolinium-labeled nanoparticles to the sentinel lymph node: comparison of the sentinel node visualization and estimations of intra-nodal gadolinium concentration by the magnetic resonance imaging

Sentinel node imaging is commonly performed prior to surgery for breast cancer and melanoma. While current methods are based on radio-lymphoscintigraphy, MR lymphangiography (MRL) offers the benefits of better spatial resolution without ionizing radiation. However, the optimal nanoparticle for imaging the sentinel nodes remains unclear. Gadolinium-labeled (Gd) contrast agents ranging in diameter from <1 to 12 nm were evaluated to determine which size provides the most rapid and most concentrated delivery of contrast agent to the lymph nodes in a mouse model of lymphatic metastases. Specifically, PAMAM-G2, -G4, -G6 and -G8, and DAB-G5 Gd-dendrimer agents, as well as Gadomer-17 and Gd-DTPA, were compared. Among these agents, the G6 Gd dendrimer depicted the lymphatics and lymph nodes with the highest peak concentrations and this occurred 24-36 min post-injection (p<0.01; all except G8). Based on ex vivo concentration phantoms, high accumulations of Gd(III) ions occurred within lymph nodes (1.7-4.4 mM Gd/270-680 ppm Gd) with high target to background ratios (>100). These concentrations are sufficient to contemplate the use of Gd-neutron capture therapy of regional lymph nodes. Thus, when injected interstitially, the PAMAM-G6 Gd dendrimer not only provides excellent opacification of sentinel lymph nodes, but also provides the potential for targeted therapy of sentinel lymph nodes.

Lymphatic drainage from esophagogastric tract: feasibility of endoscopic CT lymphography for direct visualization of pathways

PURPOSE

To evaluate the feasibility of an endoscopic computed tomographic (CT) lymphography technique with submucosal injection of iopamidol for direct visualization of lymphatic drainage pathways in dogs and in patients with operable esophageal cancer.

MATERIALS AND METHODS

With institutional animal committee approval, a total of 2 mL of undiluted iopamidol was injected into the esophageal (n = 6) or gastric (n = 3) submucosa in nine dogs by using a flexible endoscope. Multi-detector row CT images (section thickness, 1.25 mm) were obtained before contrast material injection and during the 10 minutes after injection. The animals were euthanized so that their lymphatic anatomy could be examined. With ethical committee approval and patient informed consent, nine patients with esophageal cancer also underwent CT lymphography with peritumoral injection of 2 mL of iopamidol, followed by esophagectomy and regional lymph node dissection with CT lymphographic guidance. The histopathologic features of dissected nodes, including sentinel lymph nodes (SLNs), were examined.

RESULTS

CT lymphography depicted the direct connection of lymphatic drainage vessels with enhanced and/or unenhanced nodes (ie, SLNs) as early as within 5 minutes after contrast material injection in all subjects. All 13 SLNs in dogs (1.4 nodes per animal) and 18 SLNs in patients (two nodes per patient) were found and dissected at the correct location by using CT lymphographic guidance. In patients, histopathologic examination revealed the high predictive value of CT lymphographic-guided SLN biopsy: Only one of the preoperatively identified SLNs in three patients and both SLNs and adjacent nodes in two patients were positive for metastasis; all resected nodes in the remaining four patients were negative.

CONCLUSION

Endoscopic CT lymphography is a feasible method for visualizing the direct connection between and the accurate anatomic location of SLNs and lymphatic drainage vessels.

Video-Assisted Breast Surgery: Reconstruction after Resection of More than 33% of the Breast

BACKGROUND

Improvements in reconstructive mammoplasty methods have made it possible to resect more of the mammary gland while achieving good esthetic results in breast-conserving surgery. We report the esthetic results of extended wide resection of the breast with reconstruction procedures.

METHODS

Breast-conserving surgery was performed using a video-assisted breast surgery (VABS) technique. Breast reconstruction was simultaneously performed using the following three methods: mobilization of the remnant mammary gland, transplantation of the lateral tissue flap, and filling with an absorbent synthetic fiber mesh or cotton. The cosmetic results were evaluated with an original five-item-by-four-step scoring system: ABNSW-assessing asymmetry, breast shape, nipple shape, skin condition, and wound scar.

RESULTS

From December 2001 through March 2006, we performed endoscopic VABS in 130 patients with breast diseases. The candidates were 29 patients with breast cancer who required resection of more than 33% of the mammary gland because of ductal carcinoma in situ (1 patient), multiple cancers (6 patients), widely extended lesions (20 patients), and lesions after preoperative systemic therapy (2 patients). Twenty-one patients underwent resection of 33% to 50% of the breast, and 8 underwent resection of more than 50% of the breast. All surgical margins were negative on examination of permanent histological preparations. The original shape of the breast was preserved. There was no local recurrence after follow-up times of 33 months (maximum) and 19 months (average).

CONCLUSIONS

The newly devised reconstruction methods with VABS can markedly increase the mammary gland resection volume while achieving a good esthetic outcome, ensuring a precise disease-free surgical margin, and expanding the indications for breast-conserving therapy.

Breast Sentinel Lymph Node Navigation With Three-Dimensional Interstitial Multidetector-Row Computed Tomographic Lymphography

OBJECTIVE

Three-dimensional multidetector-row computed tomographic lymphography (3D MDCT-LG) with interstitial injection of a widely available nonionic monometric contrast medium iopamidol was used for navigation of breast sentinel lymph node (SLN) biopsy.

METHODS

3D MDCT-LG was obtained after massage of the interstitially injection sites of a total of 4-5 mL undiluted iopamidol at periareolar and peritumoral areas in 68 consecutive patients with early-stage breast cancer, using a 4 detector-row CT scanner. Drainage lymphatic patterns and SLN anatomy were assessed on 3D MDCT-LG images. 3D MDCT-LG-navigated SLN biopsy with combined use of blue dye was followed by backup axillary lymph node dissection to evaluate accuracy of SLN biopsy.

RESULTS

The 3D MDCT-LG images clearly localized primary SLNs by visualizing the direct connection between these nodes and their afferent lymphatic vessels on detailed anatomy of the surrounding structures in all patients. Drainage lymphatic pathways on these images were classified into 4 patterns: single route/single SLN (39 cases, 57%), multiple routes/multiple SLNs (10 cases, 15%), single route/multiple SLNs (9 cases, 13%), and multiple routes/single SLN (10 cases, 15%). Under 3D MDCT-LG navigation, SLNs was found at the accurate location in all patients. With backup axillary lymph node dissection, metastasis was found in 14 (20%) patients, and 8 of these patients had metastasis only in the preoperatively identified SLNs. In other 5 positive patients, metastasis was found both in the SLN and non-SLNs. However, micrometastasis eventually was found only in non-SLN in an elderly patient. Overall, the sensitivity, false-negative rate, and accuracy of 3D CT-L-navigated SLN biopsy were 92% (13/14 patients), 7% (1/14 patients), and 98% (67/68 patients), respectively.

CONCLUSIONS

Topographic 3D interstitial MDCT-LG can be a widely available and reliable navigator for breast SLN biopsy.

Detection of Urinary Tract Stones at Low-Radiation-Dose CT with Z-Axis Automatic Tube Current Modulation: Phantom and Clinical Studies

PURPOSE

To evaluate depiction of urinary tract calculi at computed tomography (CT) with a z-axis modulation technique at various noise indexes to reduce radiation dose and preserve image quality.

MATERIALS AND METHODS

Sixteen radiopaque kidney stones (2.5-19.2 mm in diameter) were embedded in the collecting systems of two bovine kidneys immersed in a water bath. A kidney phantom was made by placing the kidneys in an elliptical Plexiglas phantom (32 x 20 x 20 cm) filled with physiologic saline. The phantom was scanned at 16-detector row CT with a fixed tube current (300 mA) and z-axis modulation at noise indexes of 14, 20, 25, 35, and 50; remaining imaging parameters were held constant. Two abdominal radiologists reviewed images from most to least noisy. Images were evaluated for presence of stones and size, site, and attenuation value of each stone. Readers also graded conspicuity and margins of each stone on a five-point scale. In addition, follow-up studies of 22 patients (mean age, 46 years; range, 26-57 years; male-female ratio, 14:8) with kidney and ureteral stones who underwent CT with z-axis modulation (noise index, 14 and 20) were evaluated in the same manner. Statistical analysis was performed with the Student t test, Wilcoxon signed rank test, and kappa test of interobserver agreement. Institutional review board approval was obtained, and informed consent was not needed.

RESULTS

In the phantom study, all 16 stones were identified on images obtained with a fixed tube current and z-axis modulation at noise indexes of 14, 20, and 25 (with a reduction in radiation dose of up to 77% compared with that of fixed tube current scanning). Three stones (<5 mm) were not visualized with z-axis modulation at noise indexes of 35 and 50. No significant difference was shown for conspicuity of kidney stones in 22 patients who underwent CT with z-axis modulation (with a 43%-66% reduction in radiation dose) when compared with results of previous fixed tube current studies (P > .05).

CONCLUSION

Kidney stones (< or =2.5 mm) can be adequately depicted with the z-axis modulation technique, with a 56%-77% reduction in radiation dose. In patients with urinary tract stones, the technique results in a 43%-66% reduction in radiation dose at noise indexes of 14 and 20 without compromising stone depiction.