Percutaneous computed tomography lymphography in the rabbit by subcutaneously injected nanoparticulates

RATIONALE AND OBJECTIVES: Surgical lymphangiography is infrequently used in staging cancer because of its inherent limitations. Radiopaque nanoparticulates target lymph nodes draining interstitial tissues and could make percutaneous lymphography feasible. METHODS: Experimental nanoparticulate contrast agent formulations were injected subcutaneously in the forepaw or hindpaw of normal rabbits or rabbits with induced reactive nodal hyperplasia. Axillary and popliteal nodes were imaged with thin-section computed tomography (CT) using quantitative methods to measure node enhancement. Dose-response (0.1-2.0 ml) and time course (4 hr to 10 weeks) of enhancement were assessed. RESULTS: Nodal enhancement above 100 Hounsfield units was consistently obtained. Enhancement was significantly related to dose and peaked at 10 hr with slow washout over the observation period. Nodes with reactive hyperplasia were larger and had heterogeneous enhancement patterns distinctly different from normal nodes. CONCLUSION: Percutaneous CT lymphography effectively depicts the macroscopic intranodal architecture in rabbits.     

Characterization of reactive versus tumor-bearing lymph nodes with interstitial magnetic resonance lymphography in an animal model

RATIONALE AND OBJECTIVES: To determine if magnetic resonance lymphography performed with subcutaneously administered AMI-227, a nanoparticulate iron oxide contrast agent, can distinguish reactive from tumor-bearing lymph nodes. MATERIALS AND METHODS: Mature male Copenhagen rats were inoculated with cell suspensions of R3327-MAT-LyLu rat prostate carcinoma (n = 21) or Freund's complete adjuvant (n = 15) in the left footpad to generate ipsilateral popliteal lymph node metastases or lymphadenitis. At 12 to 14 days after inoculation, T1-and T2-weighted magnetic resonance images of bilateral popliteal areas were obtained before and 24 hours after subcutaneous administration of AMI-227. Contrast-to-noise ratios were calculated in precontrast and postcontrast images. Bilateral popliteal nodes were excised for pathologic assessment. RESULTS: AMI-227 resulted in decreased contrast-to-noise ratios in reactive (T1-W = -7.01 +/- 1.13, T2- W = -31.64 +/- 5.35) and normal (T1 - W = -13.56 +/- 1.97, T2 - W = -21.62 +/- 2.51) nodes. Contrast-to-noise ratios were unchanged (T1 - W = -0.22 +/- 1.71, T2 - W = -2.20 +/- 4.19) in tumor-containing nodes. These differences in contrast-to-noise ratio changes between tumor-bearing versus nontumor-bearing nodes were statistically significant (P < 0.05). Histologic analysis showed similar distribution of AMI-227 within normal and reactive nodes, but not in tumor-bearing nodes. CONCLUSIONS: Differences in AMI-227-uptake between tumor- and nontumor-bearing nodes detected with magnetic resonance imaging are helpful for distinguishing the two entities.     

Pulmonary delivery of nanoparticles of insoluble, iodinated CT X-ray contrast agents to lung draining lymph nodes in dogs

Lung cancer continues to be a leading cause of death around the world. Staging of this disease is critically dependent upon the involvement or noninvolvement of the lymph nodes which drain the region of lung containing the lesion/tumor. Palpation, unenhanced CT, and lymph node excision (i.e., mediastinectomy) are currently used to ascertain the status of these regional draining lymph nodes. The work reported herein details the first efforts toward the pulmonary instillation of iodinated nanoparticles for contrast-enhanced CT of lung draining lymph nodes. The data reflect the impact of dose, time post instillation, and formulation (surfactant) upon the observed CT enhancement of the tracheobronchial lymph nodes of beagle dogs. In addition, initial safety is discussed with both macroscopic and microscopic observations. The results indicate that pulmonary instillation of small volumes of iodinated nanoparticles could be successfully used to aid staging of lung cancer by CT imaging.     

Surgical treatment of penile cancer: a follow-up report

One hundred and fifteen patients with penile cancer were treated at Roswell Park Memorial Institute from 1952 to 1975. A full follow-up is reported and factors involving the prognosis are analyzed. Although the clinical error of staging was near 30%, the lymphography results suggest that this study may result in added improvement in preoperative staging. Early diagnosis, adequate surgical resection, and lymph node dissection will improve the survival significantly. When dealing with an individual patient the prognosis is poor when any one or more of the follow factors are present: the lesion involves the shaft; there is a positive margin at the surgical resection; total penectomy is necessary to obtain tumor-free margin; lymphography is positive for tumor involvement of lymph nodes; lymph node dissection has not been performed; positive lymph nodes are found on surgical exploration. The good prognostic factors include: a lesion confined to the glans and partial penectomy is sufficient to obtain a tumor-free margin of resection; no clinical evidence (including lymphography) of lymph node invovlement; performance of lymph node dissection. The histological grading of the tumor should not influence the clinical decision for treatment in our opinion at this time, based on our current results. Further prospective studies of different factors involved in etiology, diagnosis, and treatment of penile cancer are suggested.     

Variability in the detection of enlarged mediastinal lymph nodes in staging lung cancer: a comparison of contrast-enhanced and unenhanced CT

OBJECTIVE: Because CT protocols for staging lung cancer vary and little information exists regarding the diagnostic importance of using i.v. contrast material, our intent was to evaluate intra- and interobserver agreement in the detection of enlarged mediastinal lymph nodes, comparing i.v. contrast-enhanced and unenhanced CT. SUBJECTS AND METHODS: Fifty patients with known or suspected bronchogenic carcinoma underwent unenhanced thoracic CT followed by contrast-enhanced CT. Three observers noted enlarged lymph nodes (> 10 mm in the short axis) and assigned the enlarged nodes to American Thoracic Society nodal station designations. Enlarged lymph nodes were grouped two ways: by assigning the exact number of enlarged lymph nodes found (zero, one, two, three, four or more), and by assigning whether at least one, or no, enlarged mediastinal lymph nodes were found at a station ("one or none"). Agreement levels were determined for inter- and intraobserver interpretations using weighted kappa statistics and the McNemar test. RESULTS: The number of enlarged lymph nodes with enhanced CT was 11% higher than on unenhanced studies (418 versus 377; p = .044). Numbers of enlarged lymph nodes were different for five stations; however, the numbers were small except for the right upper paratracheal station (2R) (contrast-enhanced, 68 enlarged lymph nodes; unenhanced, 44 enlarged lymph nodes; p = .014). With regard to all stations together, intraobserver agreement between contrast-enhanced and unenhanced studies was almost perfect (kappa range, .85-.94), and no difference was found for any observer in the proportion of patients with at least one enlarged lymph node. Interobserver agreement was substantial or almost perfect for the total number of enlarged lymph nodes. For specific stations, the lowest kappa value was .48 at 2R. One observer reported more patients with at least one enlarged lymph node with contrast enhancement at station 2R (p = .031). Greater agreement existed between two observers at station 2R with contrast enhancement versus no enhancement (kappa = .85 versus .48; p = .02). Conclusions matched, and calculations of estimated kappa values gave similar results for determination of the specific number of enlarged lymph nodes at a station and the "one or none" category. CONCLUSION: We found high agreement for intra- and interobserver interpretations for contrast-enhanced and unenhanced CT, although contrast-enhanced CT revealed more enlarged lymph nodes, especially at station 2R.     

Age-related changes in localization of injected radiolabelled lymphocytes in the lymph nodes of antigen-stimulated mice

The localization of i.v. injected syngeneic lymph node cells, radiolabelled with 51Cr or 75Se-L-selenomethionine, was studied in male CBA/H mice aged between 3 and 30 months. The following results were obtained. (1) Localization of cells from young adult donors was greater in the s.c. lymph nodes of old than of young recipients, the main increase being between 15 and 17 months of age. Increases in lymph node weight and DNA-synthesis were also seen at this time; but the rise in cell localization was significant even when calculated per unit of tissue weight. Splenic localization either declined slightly with age or, like the liver, showed no significant change. (2) Local antigenic stimulation by a single injection of sheep erythrocytes into one front footpad, 24 hr before lymph node cell injection, resulted in increased localization in the regional lymph nodes of 3-17 month old, but rarely of 24-30 month old mice. (3) No consistent differences in localization were observed between lymph node cells from 4-month and 25-month old donors. Both age-related and antigen-related increases in cell localization were at least partly attributable to an enhanced rate of entry of lymphocytes from the blood to the lymph nodes. Although the changes underlying the decline in antigen-related localization of cells in old recipients have still to be clarified, it is probable that the defective immune responses of old mice result partly from this decline.     

Spiral CT angiography in the diagnosis of central pulmonary embolism: comparison with pulmonary angiography and scintigraphy

PURPOSE: To evaluate the accuracy of spiral CT angiography in the diagnosis of central pulmonary embolism (PE). MATERIAL AND METHODS: A retrospective study was undertaken in a population of 90 patients who were evaluated with spiral CT angiography (acquisition: 12 to 24 s with or without strict apnea; injection of 90 cm3 of 12, 20 or 30% contrast material at a rate of 4 to 7 cm3, selective pulmonary angiography of each lung (n = 55) and/or ventilation-perfusion (VP) scanning (n = 35). RESULTS: Among the 55 patients evaluated with both spiral CT and angiography, central pulmonary embolism was excluded in 19 patients (34%), assessed in 29 patients (53%) whereas CT examination was considered as inconclusive in 7 patients (13%) due to interpretive difficulties at the level of obliquely oriented arteries and/or presence of hilar lymph nodes (sensitivity: 90.5%; specificity: 82.6%). With spiral CT, the finding of 95 central emboli (3 main, 61 lobar and 31 segmental) corresponded exactly to the angiographic findings; spiral CT enabled direct visualization of intraluminal filling defects (n = 95) whereas the angiographic recognition of PE was based on direct (n = 57) and indirect (n = 38) signs. Spiral CT angiography was more sensitive and specific than VP scanning. CONCLUSION: Spiral CT angiography appears as a sensitive and specific noninvasive method for the diagnosis of central PE.     

Antistaphylococcal and antistreptococcal killing kinetics of ciprofloxacin, ofloxacin, sparfloxacin, and trovafloxacin

BACKGROUND: Use of blood culture studies for early diagnosis of Mycobacterium avium complex (MAC) infection has become important due to the recent development of effective antibiotic therapy for this condition. This study assessed the abdominal computed tomography (CT) findings in patients with AIDS who presented with bacteraemic MAC infection. METHODS: A retrospective analysis of abdominal CT scans was performed in 24 patients who presented with MAC-positive blood culture. CT images were reviewed specifically to evaluate for lymph node enlargement and attenuation, hepatomegaly, splenomegaly, bowel wall abnormality and for any other pathological changes. Comparison was made to prior reports of the CT findings in this disease process. RESULT: Enlarged intra-abdominal mesenteric and/or retroperitoneal lymph nodes were found in 10 patients (42%). These nodes were characterized by homogeneous, soft-tissue attenuation in eight of the 10 patients. Hepatomegaly, splenomegaly and small bowel wall thickening were noted in 12 (50%), 11 (46%) and four (14%) patients, respectively. CT findings were evaluated as normal in six (25%) patients. CONCLUSIONS: Enlarged mesenteric and/or retroperitoneal lymph nodes in AIDS patients with bacteraemic MAC were observed much less frequently on CT than previously reported in AIDS patient populations. Normal abdominal CT findings do not exclude this diagnosis and may reflect a trend towards earlier detection of MAC disease.     

Effect of sublethal X-irradiation on follicular trapping of immune complexes in the mouse lymph node

In one set of experiments, the effect of sublethal X-irradiation on the 24 h localization of subcutaneously injected immune complexes in the lymph node follicles was studied in mice which were given HRP-anti-HRP complexes into the rear footpad at 1-3 weeks after irradiation and killed 1 day later. The 24 h follicular localization of injected immune complexes in draining popliteal nodes was severely impaired at 7 days after irradiation, at which time residual follicles were markedly depleted of B lymphocytes. In following weeks, residual follicles began to be repopulated, and the 24 h follicular localization of immune complexes became restored. Follicular dendritic cells (FDC), as was detected by the in vitro trapping assay and/or by the immunostaining for complement receptors CR1, were present in lymph nodes at any time after irradiation. Another group of mice were given HRP-anti-HRP complexes at 6 days of X-irradiation and killed from 15 min to 24 h later. Following the injection, complexes localized in residual follicles in draining nodes within 15 min but soon diminished in density and finally disappeared by 24 h after injection. It is obvious that sublethal irradiation affect neither transport of immune complexes to lymph node follicles nor their localization in these follicles. Rather rapid disappearance after temporal localization of immune complexes in residual follicles irradiated mice indicates that persisting FDC were unable effectively to trap immune complexes which were transported and localized in residual follicles. Ineffective trapping by FDC of immune complexes temporally localized in residual follicles is discussed in relation to the depletion of follicular B lymphocytes due to X-irradiation.     

Indicator measurement in tissues: CT with iohexol versus storage-phosphor autoradiography with carbon-14-labeled inulin

RATIONALE AND OBJECTIVES: Computed tomography (CT) provides accurate measurement of blood iodine concentration in vivo, as well as in phantoms simulating tissue; however, its ability to measure radiopaque agents in biologic tissues in comparison with a standard technique does not seem to have been demonstrated. To validate the performance of CT imaging for quantification of contrast media in a variety of biologic tissues in vivo, a comparison between CT imaging with an iodinated contrast agent (iohexol) and the reference tracer quantification technique (storage-phosphor autoradiography with carbon-14-labeled inulin) was performed. MATERIALS AND METHODS: Six New Zealand White rabbits were injected intravenously with a cocktail of iohexol and C-14-labeled inulin at different dose ratios and sacrificed shortly after injection to arrest blood flow at different stages of tissue tracer distribution. One rabbit received no iohexol-inulin mixture and provided baseline data. Liver, spleen, kidneys, testis, and heart were excised and rapidly frozen. Each organ was scanned with CT (1-mm contiguous sections) to determine tissue iodine distribution. Twenty-micrometer tissue slices were made in the same planes in which the CT images had been acquired, and storage-phosphor screen autoradiography was performed to quantify C-14-labeled inulin distribution. RESULTS: Digital image analysis of CT images and autoradiograms was performed on spatially matched regions, and resultant tracer concentrations were compared. Tracer concentrations were highly correlated, with resultant R2 values exceeding 0.9 in all tissues. CONCLUSION: The highly correlated results for iodinated tracer quantification in tissues for CT versus those obtained with the reference technique validate the performance of CT as an accurate means of measuring concentration of radiopaque agent in tissue, independent of tracer dose.     

Computed tomography, ultrasound and lymphography in the diagnosis of malignant lymphoma

Lymphographic findings were compared with the results at histopathology in 42 laparotomized patients with malignant lymphoma. Of 12 patients with lymphographically suggested lesions in normal-sized lymph nodes, only one had pathologic changes at histologic examination. Computed tomography gave a better idea of the extent of the disease than lymphography. Moreover, CT had an equal diagnostic accuracy as lymphography for demonstrating enlarged para-aortic lymph nodes. CT should therefore be able to replace lymphography in examination of malignant lymphoma. Ultrasound had the same diagnostic accuracy as CT regarding the upper and middle abdomen but not in the lower abdomen. Ultrasound is of special value in thin patients and when guided needle biopsy is required.     

Optimizing contrast enhancement during helical CT of the liver: a comparison of two bolus tracking techniques

OBJECTIVE: The purpose of this study was to evaluate a recently developed hardware and software system for CT scanning that generates images in real time and switches to helical CT scanning by either a visual cue or a region of interest (ROI) amplitude threshold. SUBJECTS AND METHODS: We randomly and prospectively divided 120 abdominal CT examinations into three groups. Two groups received 75 ml of contrast agent at 1.5 ml/sec. Helical CT scanning began after visualization of the contrast bolus arrival in the hepatic veins (visual cue triggering) (39 patients) or after reaching an ROI threshold (automated ROI threshold triggering) (39 patients). A third group served as a control group (42 patients) and received 150 ml of contrast agent at 1 ml/sec. Quality of hepatic enhancement was assessed objectively and subjectively. Comparisons were made after stratifying each group into three weight classes. RESULTS: Errors occurred in 12 (31%) of 39 examinations in the group with automated ROI threshold triggering. In that group, we found a significantly (p < .04) lower mean hepatic enhancement in two of three weight categories, and a significantly (p < .04) lower mean subjective scan quality in one of three weight categories, than we found in the group with visual cue triggering. CONCLUSION: Optimizing portal venous phase helical CT of the liver after a low-volume bolus of contrast agent and an injection rate of 1.5 ml/sec is best achieved by initiating helical CT scanning after visualizing the contrast bolus arrival within the liver rather than after reaching a preset attenuation threshold.     

Re-mediastinoscopy in the assessment of resectability of lung cancer

OBJECTIVE: Thirty-one patients underwent re-mediastinoscopy in the diagnostic assessment of lung cancer. The reason for a repeat mediastinoscopy was either a negative result at the first operation in spite of CT indication of enlarged nodes or an incomplete first mediastinoscopy. METHODS: All patients underwent a conventional mediastinoscopy. RESULTS: In 22 patients with enlarged mediastinal lymph nodes at computed tomography, 10 had a positive lymph node histology at re-mediastinoscopy, while 12 were negative. In 9 patients with no enlarged mediastinal nodes at CT scan, but incomplete biopsies at the first mediastinoscopy, 1 patient had lymph node metastases. The median duration from the first to the second mediastinoscopy was 43 days. No major complications occurred. The staging of the patients was greatly affected by the re-mediastinoscopy. Of 31 patients judged as operable according to the initial mediastinoscopy only 60% were found to be operable following the second mediastinoscopy. CONCLUSION: This study has demonstrated the value of re-mediastinoscopy in assessment of resectability of lung cancer.     

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INTRODUCTION: High-resolution computed tomography (HRCT) with iodinated contrast material has been used by many authors to study solitary pulmonary nodules (SPNs). The degree of enhancement was correlated with the nodule malignancy. MATERIAL AND METHODS: Forty adult patients were examined, before and after contrast agent administration, with incremental dynamic CT. We selected 22 patients with SPNs (3-30 mm phi, except one with 40 mm phi). The CT numbers of the inner nodule were calculated before and 1, 2 and 3 minutes after the i.v. administration of a weight-related dose (1.5 mL/kg/min) of nonionic iodinated contrast agent. A dose of 100 mL contrast agent was used in the first 6 patients. The difference in CT numbers between unenhanced images and the images with maximum enhancement (max. attenuation) was also calculated. RESULTS: Histologic diagnoses included 4 tuberculomas, 3 hamartomas and 15 malignant tumors (9 adenocarcinomas, 5 squamous cell carcinomas and 1 non-Hodgkin lymphoma). The CT numbers (in Hounsfield units, HU) of malignant nodules ranged 12-31 HU (mean: 21.5 HU) before contrast agent administration; the "long-standing" tuberculomas ranged 11-22 HU (mean: 16.5 HU) and the hamartomas had a mean density of 10.5 HU. We excluded for the study two "fresh" tuberculomas, one of which was surrounded by a low-attenuation infiltrate (the halo sign). We selected a threshold value of 20 HU on enhanced CT images to distinguish malignant (> or = 20 HU) from benign (< or = 20 HU) nodules. All lung cancers had complete enhancement (mean density: 35.5 HU). With 20 HU as the threshold value for a positive test, sensitivity was 100%, specificity 85.7%, positive predictive value 93.8% and negative predictive value 100%; test bias was 1.067. CONCLUSION: Positron emission tomography (PET) with 2-[fluorine-18] fluoro-2-deoxy-D glucose is reported to be as accurate as enhanced HRCT, but it does not provide accurate morphological information, is not widely available and it is quite expensive: therefore, in our opinion, CT should be preferred. After examining over 100 patients, we may use our results in the decision analysis comparing surgical risk with cancer risk.     

Localization of tumor-reactive lymph node lymphocytes in vivo using radiolabeled monoclonal antibody

BACKGROUND: Lymph node lymphocytes vary in their responsiveness to tumor. A technique has been developed that uses radiolabeled monoclonal antibody (MoAb) against the tumor-associated mucin, TAG-72, and a gamma-detecting probe by which lymph nodes containing microscopic tumor and/or shed TAG-72 can be identified in vivo. The immunologic characteristics of these lymph nodes were examined. METHODS: Patients with colon cancer received 125I-labeled MoAb CC49 by intravenous injection preoperatively. During laparotomy lymph nodes that appeared normal on inspection and palpation but which contained radiolabeled MoAb were identified using a hand-held gamma-detecting probe. These lymph nodes and other lymph node and tumor specimens were resected for analysis. RESULTS: Lymph nodes identified by the probe were found by immunohistochemical studies to contain microscopic tumor and/or shed antigen associated with germinal centers. They were characterized by greater CD4+:CD8+ ratios, rates of expansion, and cytolytic activity compared with lymphocytes from lymph nodes with macroscopic tumor, noninvolved lymph nodes, and tumors. All lymph node lymphocytes identified by the probe demonstrated significant proliferative responses to autologous tumor and, in contrast to lymphocytes from noninvolved lymph nodes, significant proliferative responses to allogeneic TAG-72+ tumor cells and to soluble TAG-72+ mucin. CONCLUSIONS: By locating lymph nodes with microscopic tumor and/or shed antigen, the use of radiolabeled MoAb in vivo can be used to reproducibly identify tumor-reactive lymph node lymphocytes. This technique may be useful in identifying cells for use in adoptive immunotherapy programs and in studying the regulation of immune responses in vivo.     

Passive transfer of experimental hypersensitivity pneumonitis with lymphoid cells in the rabbit

Although precipitating antibody is associated with human hypersensitivity pneumonitis, there is evidence that cell-mediated hypersensitivity may be involved in disease pathogenesis. In this study, interstitial, and peribronchial lesions were produced by respiratory challenge of rabbits passively sensitized with ovalbumin-sensitive lymph node cells. Ovalbumin sensitivity of donor rabbits and lymph node cells was demonstrated by skin testing, migration inhibition factor (MIF) production using alveolar wash cells as migrating cells, and lymphocyte stimulation. Passive cell transfer was accomplished by intraperitoneal injection with all lymph node cells obtained from one donor transferred to one recipient. Recipients were challenged by aerosol or intratracheal injection of antigen immediately or 24 hr after passive sensitization and were killed 48 hr after challenge. Lesions in rabbits passively sensitized by lymph node cells and challenged with antigen by intratracheal inoculation consisted of focal pneumonitis with intra-alveolar edema and infiltrates of mononuclear cells in alveoli and alveoli septa. Aerosol challenge of passively sensitized animals produced similar changes, but peribronchial tissue containing macrophages and germinal centers was prominent in this group. Antiovalbumin serum recipients challenged by intratracheal injection demonstrated only mild peribronchial mononuclear cell infiltrates, without pneumonitis. Control animals receiving lymph node cells only or challenge only demonstrated no changes in lung histology.     

US case of the day. Diffuse large B-cell lymphoma (posttransplant lymphoproliferative disorder [PTLD])

OBJECTIVE: We describe two new CT findings of congestive heart failure (CHF): enlarged mediastinal lymph nodes and hazy heterogeneous mediastinal fat. MATERIALS AND METHODS: Forty-six patients were retrospectively identified who had major and minor clinical signs of congestive heart failure and had undergone chest CT during their symptomatic period. Two radiologists reviewed the CT studies and by consensus documented the presence or absence of imaging findings of CHF, including interstitial abnormalities, vascular redistribution, axial thickening, pleural effusions, cardiac enlargement, and mediastinal abnormalities. RESULTS: Smooth septal thickening, bilateral pleural effusions, vascular redistribution, and cardiac enlargement were the most common CT findings in patients with CHF. Enlarged mediastinal lymph nodes and hazy mediastinal fat were seen in 55% and 33% of cases, respectively. In a cohort of 17 patients with elevated pressures in the pulmonary capillary wedge documented within 24 hr of CT, CT scans revealed lymphadenopathy in 14 patients (82%) and inhomogeneous fat in 10 patients (59%). CONCLUSION: Enlarged mediastinal lymph nodes and hazy mediastinal fat occur in patients with CHF and are revealed by CT. Lymphadenopathy in patients with CHF does not necessarily indicate malignancy or an infectious process.     

Mediastinal lymph node metastasis from esophageal carcinoma: CT assessment with pathologic correlation

Computed tomographic (CT) scans were performed in 179 patients with esophageal carcinoma to evaluate mediastinal lymph node metastasis. Histopathologic findings were compared with CT findings in a total of 7,218 resected lymph nodes. First, the criterion for lymph node metastasis on CT scans was 10 mm or more in long transverse diameter. The overall sensitivity and positive predictive value (PPV) were 19% (60 of 317 nodes) and 33% (60 of 180 nodes), respectively. Analysis of each of the eight subgroups of mediastinal nodes revealed that the PPV was more than 70% in node Nos. 105, 108, 110, and 112. In other subgroups, however, the PPV was less than 60%. Sensitivity was less than 50% in all eight subgroups. Second, the criterion for metastasis was 10 mm or more in short transverse diameter. The overall sensitivity and PPV were 8% (26 of 317 nodes) and 63% (26 of 41 nodes), respectively. Analysis of subgroups showed that the PPV in No. 106 nodes increased to 92%. In No. 106 nodes, use of a 5 mm criterion in long transverse diameter increased sensitivity to only 55%. Of the 317 histopathologically proven metastatic lymph nodes, 90 nodes (28%) were 10 mm or more in size, 112 (35%) were 5-10 mm, and 115 (36%) were less than 5 mm. Of the 6,901 non-metastatic lymph nodes, 473 nodes (7%) were 10 mm or more in size. Small (less than 5 mm in size) metastatic nodes were present in all eight subgroups. Among No. 107 and 109 nodes, large (10 mm or more in size) nonmetastatic nodes were prominent, resulting in low sensitivity and PPV. We conclude that CT does not provide an accurate assessment of metastatic versus non-metastatic mediastinal lymph nodes in patients with esophageal carcinoma.     

Small lymph nodes of the abdomen, pelvis, and retroperitoneum: usefulness of sonographically guided biopsy

PURPOSE: To evaluate the usefulness of sonographically guided percutaneous biopsy of small lymph nodes in the abdomen, retroperitoneum, and pelvis. MATERIALS AND METHODS: From May 1995 through January 1997, 35 sonographically guided lymph node biopsies were performed in 34 patients. All biopsies were performed with a 20- (n = 18) or 22-gauge (n = 10) self-aspirating needle alone or in combination (n = 7). To determine the amount of compression achieved with the transducer, the skin-to-lesion distance on reference computed tomographic (CT) scans was compared with that on sonograms. A biopsy was considered successful if a specific benign or malignant diagnosis was rendered by the pathologist. RESULTS: Of 35 sonographically guided biopsies, 30 (86%) were successful. Diagnoses included 26 (74%) cases of carcinoma, three (9%) cases of benign reactive lymphocytosis confirmed at open biopsy, and one (3%) case of a lymph node with a positive acid-fast bacilli stain. The average lymph node diameter was 2.1 cm (range, 0.9-4.3 cm). With sonography, a mean of 2.5 needle passes (range, 1-5) were made per biopsy. Transducer compression reduced the skin-to-lesion distance from an average of 8.8 cm (at CT) to 4.5 cm. CONCLUSION: Sonographic guidance seems to provide a reasonable alternative to CT in biopsy of small abdominal, pelvic and retroperitoneal lymph nodes.     

Distribution and contrast enhanced CT appearance of abdominal tuberculous lymphadenopathy

PURPOSE: To clarify the contrast enhanced CT features and anatomic distribution of the disseminated vs non-disseminated tuberculosis (TB) involving abdominal lymph nodes. MATERIALS AND METHODS: The contrast enhanced CT findings of abdominal lymphadenopathy in 25 patients, including disseminated TB associated with miliary TB of the lung (n = 5) and non-disseminated TB (n = 20), were retrospectively evaluated in a blind review to assess our criteria of morphology, density and location of the involved lymphadenopathy. RESULTS: The enhancement patterns of disseminated TB were not different from those of non-disseminated TB. Ninety-six percent of the patients had peripheral rim enhancement, and 60% showed a multilocular appearance. The enlarged lymph nodes of TB were less than 4 cm in diameter. Lymphadenopathy caused by hematogenous dissemination often accompanied splenic involvement showing multiple low-density foci in the spleen. The predominant sites of lymphadenopathy of disseminated TB were hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric, and both upper and lower portions of the retroperitoneal lymph nodes, whereas non-disseminated TB mainly involved hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric and upper retroperitoneal lymph nodes, excluding the lower retroperitoneal lymph nodes. By combining contrast enhancement patterns and the anatomic distribution of lymphadenopathy shown on the contrast enhanced CT images, reviewers made a correct diagnoses of tuberculosis in 94%, of cases, with a specificity of 95% and sensitivity of 92%. CONCLUSION: Contrast enhanced CT patterns correlate well with the pathologic features of tuberculous lymphadenopathy. A different anatomic distribution between disseminated and non-disseminated TB involving the lower retropentoneal lymph nodes was recognized in this study.