Tuberculosis vs. chronic lymphocytic leukaemia in mediastinal lymph nodes using computed tomography

BACKGROUND

The enlarged mediastinal lymph nodes caused by tuberculosis (TB) and chronic lymphocytic leukaemia (CLL) are similar, sometimes resulting in misdiagnosis of the two diseases.

OBJECTIVE

To determine the differential characteristics of enlarged mediastinal lymph nodes caused by TB and CLL using multidetector-row computed tomography (MDCT).

MATERIALS AND METHODS

We conducted a retrospective analysis for the anatomical distribution and enhancement patterns of mediastinal lymph nodes on MDCT in 67 consecutive patients with newly diagnosed untreated TB (58%) and CLL (42%).

RESULTS

Concerning the main anatomic distribution of lymph nodes, TB involved the 4R (n = 32, 82%) and 10R (n = 27, 69%) regions more often than CLL (n = 16, 57%; n = 12, 43%, respectively). Contrast region 1 had a greater tendency to be affected in CLL (n = 16, 57%) than TB (n = 11, 28%). TB showed peripheral enhancement in 28 cases (72%), frequently with a multilocular appearance, compared to CLL, which showed no peripheral enhancement in these cases. Homogeneous enhancement was more commonly seen in CLL than in TB (82% vs. 10%, P < 0.01).

CONCLUSION

The distribution and enhancement pattern of enlarged lymph nodes on MDCT was useful in differentiating TB and CLL.

Differentiation of tuberculosis from lymphomas in neck lymph nodes with multidetector-row computed tomography

BACKGROUND

Tuberculosis (TB) of the cervical lymph nodes may mimic lymphoma.

OBJECTIVE

To evaluate multidetector-row computed tomographic (MDCT) imaging criteria for differentiating between the two diseases.

MATERIALS AND METHODS

We retrospectively reviewed the anatomical distribution and CT enhancement patterns of the nodes in 81 patients, 27 (33%) with untreated TB and 54 (67%) with untreated lymphomas involving cervical lymph nodes. Of the patients with lymphomas, 19 (35%) had Hodgkin's disease and 35 (65%) had non-Hodgkin's lymphoma.

RESULTS

TB predominantly involved the upper cervical nodes. The supraclavicula fossa nodes on MDCT were involved more often in Hodgkin's disease (n = 15, 79%) and non-Hodgkin's lymphoma (n = 25, 71%) than in TB (n = 3, 11%). Tuberculous lymphadenopathy commonly showed peripheral enhancement, frequently with a multilocular appearance. Peripheral enhancement was significantly more frequent in TB (n = 19, 70%) than in Hodgkin's disease (n = 1, 5%) and non-Hodgkin's lymphoma (n = 1, 3%), but homogeneous enhancement was less common in the TB group.

CONCLUSION

Our findings indicate that a specific enhancement pattern of lymphadenopathy seen on MDCT was useful in differentiating between untreated TB and lymphomas of the cervical lymph nodes.

Differentiation between tuberculosis and lymphoma in mediastinal lymph nodes: Evaluation with contrast-enhanced MDCT

AIM

To determine the specific imaging criteria on contrast-enhanced multidetector computed tomography (MDCT) for differentiating between tuberculosis and lymphoma in mediastinal lymph nodes.

MATERIALS AND METHODS

The anatomical distribution and enhancement patterns of mediastinal lymph nodes on contrast-enhanced MDCT were reviewed in 37 patients with tuberculosis and 54 patients with lymphoma. Of the patients with lymphoma, 18 had Hodgkin's disease and 36 had non-Hodgkin's lymphoma.

RESULTS

Region 10R was involved more often in tuberculosis than in Hodgkin's disease and non-Hodgkin's lymphoma. Region 6 had a higher tendency to be affected in Hodgkin's disease and non-Hodgkin's lymphoma compared with tuberculosis. Tuberculosis showed peripheral enhancement in 78% of cases, frequently with a multilocular appearance, compared to Hodgkin's disease and non-Hodgkin's lymphoma, which showed peripheral enhancement in only 6 and 3% of cases, respectively. Homogeneous enhancement was more commonly seen in lymphoma (83% for Hodgkin's disease, and 83% for non-Hodgkin's lymphoma) than in tuberculosis (8%). In the determination of tuberculosis, results showed that when a peripheral enhancement pattern was seen, sensitivity was 78%, specificity was 96%, and accuracy was 89%. In the determination of lymphoma, results showed that when a homogeneous enhancement pattern was seen, sensitivity was 83%, specificity was 92%, and accuracy was 87%.

CONCLUSION

The findings of the present study indicate that specific anatomical distribution and enhancement patterns of lymphadenopathy shown on contrast-enhanced MDCT can be useful in differentiating tuberculosis from lymphoma of mediastinal lymph nodes.

Time-intensity curve parameters in colorectal tumours measured using double contrast-enhanced ultrasound: correlations with tumour angiogenesis

AIM

The aim of the study was to assess the correlation between time-intensity curve (TIC) parameters and colorectal tumour angiogenesis using double contrast-enhanced ultrasound (DCEUS), in which an intraluminal contrast agent was used in combination with an intravascular contrast agent.

METHOD

Thirty nine patients with colorectal tumours were examined preoperatively. During hydrocolonal examination with the intraluminal contrast agent, an intravascular contrast agent, SonoVue, was used to perform the DCEUS. The parameter arrival time (AT), time to peak (TTP), peak intensity (PI) and area under the curve (AUC) were measured. Postoperative specimens were assessed for microvessel density (MVD) and vascular endothelial growth factor (VEGF). The correlation between TIC parameters and the expression of VEGF or MVD was studied.

RESULTS

The mean values of AT, TTP, PI and AUC of the colorectal tumours were 14.32 ± 11.36 s, 30.61 ± 18.65 s, 20.38 ± 17.45 dB and 221.10 ± 156.09 dB.s, respectively. Both AUC and MVD were significantly higher in colorectal adenocarcinomas than in adenomas (all P < 0.05). A positive linear correlation was found between the AUC and MVD in colorectal tumours (r = 0.686, P = 0.0019). No correlation was found between VEGF and any TIC parameter.

CONCLUSION

DCEUS is a valuable method for evaluating angiogenesis in colorectal tumours in vivo. The AUC has a positive linear correlation with MVD and could form a new index for assessing angiogenesis and the biological behaviour of colorectal tumours.

First-pass perfusion imaging of solitary pulmonary nodules with 64-detector row CT: comparison of perfusion parameters of malignant and benign lesions

The purpose of this study was to determine the usefulness of first-pass whole nodule perfusion imaging in the differentiation of benign and malignant solitary pulmonary nodules (SPNs). 77 patients with non-calcified SPNs (46 malignant, 22 benign and 9 active inflammatory) underwent first-pass perfusion imaging with a 64-detector row CT scanner. Perfusion, peak enhancement intensity (PEI), time to peak (TTP) and blood volume (BV) were measured and statistically compared among different groups. Mean perfusion, PEI and BV for benign SPNs were significantly lower than those for malignant nodules (p<0.05) and active infections (p<0.05), but the differences were not statistically significant between malignant tumours and active infections (p>0.05). Receiver operating characteristic (ROC) curve analysis showed that SPNs with perfusion greater than 30.6 ml min(-1) ml(-1), PEI higher than 23.3 HU or BV larger than 12.2 ml per 100 g were more likely to be malignant. In conclusion, first-pass perfusion imaging with 64-detector row CT is a feasible way of assessing whole nodule perfusion and helpful in differentiating benign from malignant SPNs.

Quantitative assessment of first-pass perfusion of oesophageal squamous cell carcinoma using 64-section MDCT: initial observation

AIM

To clarify the feasibility of first-pass perfusion computed tomography (CT) using 64-section multidetector CT (MDCT) for tumour microcirculation of oesophageal squamous cell carcinoma, and to determine the threshold value of first-pass perfusion values for the discrimination between the microcirculation of the tumour and normal oesophagus.

MATERIALS AND METHODS

Forty-one patients with pathologically confirmed oesophageal squamous cell carcinomas served as the test group, which was subdivided into subgroups according to the pathological grades or the status of lymph node metastasis. Forty patients with a normal oesophagus served as controls. All patients underwent volume-based perfusion imaging using 64-section MDCT. Perfusion parameters including perfusion (PF), peak enhancement (PE), blood volume (BV), and time to peak (TTP) were measured. The differences in perfusion parameters between the test and control groups, and between the subgroups were compared statistically. The cut-off values were obtained statistically to discriminate microcirculation between the tumour and normal oesophagus.

RESULTS

Mean values for the BV and TTP of the tumour were 12.57+/-5.15 ml/100g (range 2.9-25.6) and 33.71+/-14.12 s (range 6-65), respectively. Mean values for the BV and TTP of the normal oesophagus were 4.33+/-3.6 ml/100 g (range 0.3-11.7) and 24.15+/-11.67 s (range 6-48), respectively. The BV and TTP were statistically higher in the test group than in the control group (p<0.05), but no statistical differences in the PF and PE were found between the test and control groups (p>0.05). There were no statistical differences in all parameters between the subgroups of pathological grades, and between subgroups with and without lymph-node metastases (p>0.05). For the discrimination of microcirculation of the tumour from that of the normal oesophagus, a threshold BV value of 6.65 ml/100g was determined and achieved a sensitivity of 95.1%, and specificity of 90%.

CONCLUSION

The first-pass perfusion technique using 64-section MDCT could be valuable to assess the microcirculation of oesophageal squamous cell carcinomas.

Adenosquamous carcinoma of the lung: CT—pathological correlation

AIM

To correlate CT morphological features and histopathological findings of adenosquamous carcinoma of the lung.

MATERIALS AND METHODS

In all, 29 patients underwent contrast-enhanced CT of an adenosquamous carcinoma of the lung, followed by resection of the cancer. Correlations between CT morphological and histopathological features were evaluated, including location, characteristics of margins, attenuation and the presence of necrosis.

RESULTS

The tumour was peripheral in 21 (72%) and central in 8 (28%) cases. The tumours varied in size from 1.1cm to 11.0cm (mean 3.8cm); 20 (69%) appeared as heterogeneous masses and 9 (31%) as homogeneous masses. The most common CT features were lobulation in 27 (93%), pleural tail in 22 (76%), spiculation in 17 (59%), necrosis in 15 (52%) and vessel convergence in 13 (45%). Among the 21 peripheral tumours, 14 (67%) showed intratumoural necrosis and 17 (81%) were heterogeneous. Among the 8 central tumours, only 1 (12.5%) showed intratumoural necrosis and 5 (62.5%) were homogeneous. These CT features corresponded mainly to solid tumour growth, which was composed of both squamous cell carcinomatous and adenocarcinomatous tissue.

CONCLUSION

Adenosquamous carcinoma of the lung is shown to be characteristically a solid, lobulated nodule or mass, more commonly peripheral than central. After intravenous injection of positive contrast medium, CT shows that the peripheral lesions are usually of heterogeneous soft-tissue attenuation.

[Effect of Astragalus saponin on vascular endothelial cell and its function in burn patients]

OBJECTIVE

To study the protective effect of Astragalus saponin (AS) on vascular endothelial cell (VEC) in burn patients.

METHODS

Eighty burn patients were divided randomly into 2 groups, the AS group and the burn control group. Blood level of circulatory endothelial cell (CEC), endothelin (ET), nitric oxide (NO), lactate dehydrogenase (LDH) and alanine transaminase (ALT) were determined before treatment and 1 day, 5, 10 and 21 days after treatment, and compared with those in 10 healthy persons as a normal control group.

RESULTS

All the parameters determined in the AS group were significantly higher than those in the normal control group. But as compared with the burn control group, the parameters in the AS group after treatment were all lower significantly.

CONCLUSION

AS has definite protective effect on VEC from injury by burn, it could also improve the function of myocardial and liver cell, alleviate the general inflammatory response simultaneously.

A study on pathogenicity of hepatitis G virus

AIM: To study the pathogenicity of hepatitis G virus (HGV) and observe the genesis and pathological process of hepatitis G.

METHODS: HGV-RNA in serum was detected by RT-PCR assay. The immunohistochemical assays of liver tissue were performed with HGV monocoloned antibody (McAb) expressed from the region of HGV NS5 nucleic acid sequence. The clinical and pathological data of 52 patients with hepatitis G were discussed. In animal experiment, the Chinese Rhesus monkeys were infected with the serum of a patient with HGV infection. And the dynamic changes in serology and liver histology of animals were observed.

RESULTS: One hundred and fifty-four patients with HGV-RNA positive were selected from 1552 patients with various kinds of hepatitis. Of 154 patients with HGV infection, 52 were infected with HGV only, which accounted for 33.8% (52/154) and 102 with positive HGV-RNA were super-infected with other hepatitis viruses, which accounted for 66.2% (102/154). The clinical and pathological observation showed that the acute and chronic hepatitis could be induced by HGV. The slight abnormality of transaminases ALT and AST in serum of monkeys lasted nearly 12 months and histological results showed a series of pathological changes.

CONCLUSION: HGV is a hepatotropic virus and has pathogenicty.

High-resolution CT analysis of small peripheral lung adenocarcinomas revealed on screening helical CT

OBJECTIVE

The purpose of this study was to determine the correlation between high-resolution CT morphologic features of small peripheral lung adenocarcinomas and tumor growth patterns.

MATERIALS AND METHODS

We examined high-resolution CT morphologic features of 59 small, surgically resected peripheral lung adenocarcinomas (diameter, 6-20 mm) that were detected on screening for lung cancer using low-dose helical CT. Among these adenocarcinomas, 14 (24%) were visible and 45 (76%) were invisible on conventional chest radiography. The correlation between high-resolution CT morphologic features and tumor growth patterns was analyzed.

RESULTS

Sixteen (94%) of 17 type A (Noguchi's classification) adenocarcinomas appeared as nodules of pure ground-glass attenuation (high-resolution CT type I). Ten (71%) of 14 type B tumors appeared as heterogeneous, low-attenuation nodules (type II). Seven (29%) of 24 type C tumors appeared as nodules with ground-glass attenuation in the periphery and a high-density central zone (type III), and 12 (50%) of 24 type C tumors appeared as homogeneous nodules with soft-tissue density (type IV). Among tumors with a replacement growth pattern, the size and CT values of type C tumors were larger than those of type A or type B tumors (p < 0.05), whereas the percentage of ground-glass attenuation and retained air space in type C tumors was smaller than those in type A or type B tumors (p < 0.01). All (100%) four type D tumors appeared to be homogeneous nodules with soft-tissue density (type IV).

CONCLUSION

Small peripheral lung adenocarcinomas shown on CT exhibit four high-resolution CT patterns that corresponded to the histopathologic findings of different tumor growth patterns.

Atypical adenomatous hyperplasia of the lung: correlation between high-resolution CT findings and histopathologic features

We describe herein the CT features of atypical adenomatous hyperplasia (AAH) of the lung and its histopathological characteristics. Among 17,919 individuals screened for lung cancer by CT scanning, ten AAH nodules were detected in nine asymptomatic subjects. On high-resolution CT, the lesions measured from 6 x 6 mm to 15 x 17 mm and their CT number ranged from -500 to -760 HU. The AAHs appeared as round nodules with smooth and distinct borders and showed a ground-glass opacity. Plain chest radiographs failed to identify all lesions. Histopathologically, AAH lesions showed atypical epithelial cell proliferation along slightly thickened alveolar septa. Whereas it is often easy to differentiate these nodules from inflammatory and benign lung lesions, histopathological examination remains at present the only method to differentiate AAH from lung cancers.

Correlation between high-resolution computed tomographic, magnetic resonance and pathological findings in cases with non-cancerous but suspicious lung nodules

Computed tomography scans, including thin-section high-resolution computed tomography (HRCT), occasionally fail to differentiate between small non-cancerous nodules from lung cancers. We describe nine such lesions ( < 20 mm in diameter) initially identified through our screening program for lung cancer using CT scanning. Pathological diagnoses included nodular fibrosis (n = 4), granuloma (n = 1), cryptococcoma (n = 1), localised organising pneumonia (n = 1), inflammatory pseudo-tumour (n = 1) and sclerosing haemangioma (n = 1). High-resolution CT findings, together with MRI findings with contrast-enhanced dynamic studies, were retrospectively evaluated. Additional cases should be identified and radiologically characterised in order to reduce the number of non-cancerous tumours that are treated by unnecessary surgery.

Visibility of small peripheral lung cancers on chest radiographs: influence of densitometric parameters, CT values and tumour type

The purpose of this study was to determine the effects of tumour density and tumour type on the visibility of small peripheral lung cancers on chest radiographs. We retrospectively evaluated the visibility of 63 small (< or = 20 mm) peripheral lung cancers on chest radiographs. 48 (76%) were detected in our low dose CT screening for lung cancer and 15 (24%) in routine clinical examination. Analysis was based on tumour optical contrast, gradient at the tumour margin, CT values and tumour type. There were 31 (49%) visible cancers and 32 (51%) invisible cancers on chest radiographs. Visible tumours had an optical density of 0.1-0.3 OD and a gradient of 0.03-0.11 OD mm-1. The mean size of visible tumour (14.3 mm) was larger than that of invisible tumour (11.1 mm; p < 0.001). The mean CT value (-140 HU) of visible tumour was higher than that of invisible tumour (-490 HU; p < 0.001). The detection rates of adenocarcinomas with lepidic growth (0% for type A, 29% for type B and 68% for type C) were less than those with hilic growth (100% for types D-F). All squamous and small cell carcinomas with hilic growth were visible on chest radiographs, but the numbers of each were small. In summary, tumour type influenced the contrast, gradient, CT values and margin of the tumour. Small adenocarcinomas with a lepidic tumour growth were less well seen on chest radiographs compared with small lung cancers with hilic tumour growth.

Results of three-year mass screening programme for lung cancer using mobile low-dose spiral computed tomography scanner

The aim of this study was to evaluate the usefulness of annual screening for lung cancer by low-dose computed tomography (CT) and the characteristics of identified lung cancers. Subjects consisted of 5483 general population aged 40-74 years, who received initial CT scans in 1996, followed by repeat annual scans for most subjects in 1997 and 1998, with a total of 13 786 scans taken during 1996-1998. Work-up examinations for patients with suspicious lesions were conducted using diagnostic CTs. The initial screening in 1996 detected suspicious nodules in 279 (5.1%) of 5483 subjects, and 22 (8%) were confirmed surgically to have lung cancer. Corresponding figures in 1997 and 1998 screening studies were 173 (3.9%) of 4425 and 25 (14%) of 173, and 136 (3.5%) of 3878 and 9 (7%) of 136, respectively. The sensitivity and specificity of detecting surgically confirmed lung cancer were 55% (22/40) and 95% (4960/5199) in 1996 and 83% (25/30) and 97% (4113/4252) in 1997 screening, respectively. 88% (55/60) of lung cancers identified on screening and surgically confirmed were AJCC stage IA. Our trial allowed detection of nearly 11 times the expected annual number of early lung cancers. Repeat CT allowed the detection of more aggressive, rapidly growing lung cancers, compared to those in the initial screening.

Growth rate of small lung cancers detected on mass CT screening

CT has recently been used in mass screening for lung cancer. Small cancers have been identified but the growth characteristics of these lesions are not fully understood. We identified 82 primary cancers in our 3-year mass CT screening programme, of which 61 were examined in the present study. The volume doubling time (VDT) was calculated based on the exponential model using successive annual CT images or follow-up CT images. All cases were also examined in the hospital by high resolution CT (HRCT). Lesions were divided into three types based on HRCT characteristics: type G (n = 19), ground glass opacity (GGO); type GS (n = 19), focal GGO with a solid central component; and type S (n = 23), solid nodule. 18 (95%) lesions of type G, 18 (95%) of type GS and 7 (30%) of type S were invisible on conventional chest radiographs. The mean size of the tumour was 10 mm, 11 mm and 16 mm for type G, type GS and type S, respectively. Most tumours (80%) were adenocarcinomas; 78% of these were GGO (type G and GS). Mean VDT values were 813 days, 457 days and 149 days for type G, type GS and type S, respectively; these are significantly different from each other (p < 0.05). Our results show that annual mass screening CT for 3 successive years resulted in the identification of a large number of slowly growing adenocarcinomas that were not visible on chest radiographs.

Rapidly growing small peripheral lung cancers detected by screening CT: correlation between radiological appearance and pathological features

12 peripheral small lung cancers (< 20 mm) of rapid growth (volume doubling time < 150 days), detected by repeated low dose CT screening, were evaluated to examine their CT features and to correlate such features with histopathological findings. Each patient's CT images, including follow-up and thin section CT images, were studied retrospectively to determine tumour growth rate and CT morphological features. Nine of the tumours exhibited a solid tumour growth pattern: seven of these showed a well defined, homogeneous, soft tissue density with spicular or lobulated margin. These seven tumours included small cell lung cancer (n = 3), moderately differentiated adenocarcinoma (n = 2), poorly differentiated adenocarcinoma (n = 1) and squamous cell carcinoma (n = 1). The other two tumours, a moderately differentiated adenocarcinoma and a well differentiated adenocarcinoma, appeared as irregular, soft tissue density nodules with poorly defined margins. The latter exhibited an air bronchogram pattern and a small cavity. The remaining three tumours exhibited a lepidic tumour growth pattern. They showed ground glass opacity or ground glass opacity with a higher density central zone on CT images and were well differentiated adenocarcinomas. In conclusion, most peripheral small lung cancers of rapid growth were adenocarcinomas. They also included small cell lung cancer and squamous cell carcinoma. The majority showed solid tumour growth pattern and lacked an air bronchogram and/or small air spaces in the nodule. Some well differentiated adenocarcinomas with lepidic tumour growth pattern also showed rapid growth.

Effect of CT digital image compression on detection of coronary artery calcification

PURPOSE

To test the effect of digital compression of CT images on the detection of small linear or spotted high attenuation lesions such as coronary artery calcification (CAC).

MATERIAL AND METHODS

Fifty cases with and 50 without CAC were randomly selected from a population that had undergone spiral CT of the thorax for screening lung cancer. CT image data were compressed using JPEG (Joint Photographic Experts Group) or wavelet algorithms at ratios of 10:1, 20:1 or 40:1. Five radiologists reviewed the uncompressed and compressed images on a cathode-ray-tube. Observer performance was evaluated with receiver operating characteristic analysis.

RESULTS

CT images compressed at a ratio as high as 20:1 were acceptable for primary diagnosis of CAC. There was no significant difference in the detection accuracy for CAC between JPEG and wavelet algorithms at the compression ratios up to 20:1. CT images were more vulnerable to image blurring on the wavelet compression at relatively lower ratios, and "blocking" artifacts occurred on the JPEG compression at relatively higher ratios.

CONCLUSION

JPEG and wavelet algorithms allow compression of CT images without compromising their diagnostic value at ratios up to 20:1 in detecting small linear or spotted high attenuation lesions such as CAC, and there was no difference between the two algorithms in diagnostic accuracy.

Characteristics of small lung cancers invisible on conventional chest radiography and detected by population based screening using spiral CT

Conventional chest radiography (CXR) is a poor diagnostic tool for detecting lung cancers at a surgically curable stage. To determine the visibility of peripheral small lung cancers on CXR, we retrospectively examined the usefulness of CXR using a consecutive series of 44 cases detected on CT screening and later confirmed by histopathology. All cases had been detected by low dose CT during a population based screening trial for lung cancer. The control group consisted of 48 chest radiographs of normal subjects. Tumour diameters ranged from 6 mm to 45 mm, with 95% (42/44) < or = 20 mm, and 5% (2/44) > 20 mm. CXR failed to detect 77% (34/44) of all cancers, including 79% (33/42) < or = 20 mm and 50% (1/2) > 20 mm. Of the 42 lung cancers < or = 20 mm, 74% (31/42) were located in the well penetrated lung zones and 71% (22/31) of these were missed on CXR. 26% (11/42) were concealed by hilar vessels, mediastinum, heart or diaphragm, and all (11/11) of these were missed on CXR. 93% (39/42) of the lung cancers < or = 20 mm were adenocarcinomas and 79% (31/39) of these were missed on CXR. 7% (3/42) were epidermoid carcinomas or small cell carcinomas and 66% (2/3) of these were missed on CXR. The overall accuracy of interpretation on CXR for lung cancers was 61%, sensitivity was 23% and specificity 96%. Although there was an association between presence of lung cancer and positive reading of CXR (chi 2 test of association, p < 0.05), the percentage of positive readings was only 23%. Thus, CXR was poor at visualizing CT detectable lung cancers of < or = 20 mm diameter, which are usually of very low density, and cannot be relied upon for detection of surgically curable small lung cancer.

Detection of small peripheral lung cancer by digital chest radiography. Performance of unprocessed versus unsharp mask-processed images

PURPOSE

To clarify whether processed digital chest radiography can improve the detection rate for small peripheral lung cancer.

MATERIAL AND METHODS

Five radiologists independently interpreted 54 digitized chest radiographs of 18 patients with small peripheral lung cancers measuring less than 20 mm, which were displayed following 3 types of digital processing: 1) an original version; 2) unsharp mask processing with a type 1 filter (very low-frequency-enhancing, mid-frequency-suppressing, and high-frequency-enhancing filter); and 3) unsharp mask processing with a type 2 filter (very low- and high-frequency-enhancing filter). A total of 1,620 pooled observations were evaluated by receiver operating characteristic (ROC) analysis.

RESULTS

The mean area under the ROC curves was 0.68 for the type 1 filter, 0.68 for the type 2 filter, and 0.65 for the unprocessed (original) image. There were no statistically significant differences among these 3 kinds of image processing (p>0.05). In all types of images, the small lung cancer with an alveolar lining tumor growth was less visible than a solid tumor growth (p<0.01); the sensitivity increased with tumor size when the 3 groups of cancers, those measuring less than 10 mm, 11-15 mm, and 16-20 mm, were compared (p<0.01).

CONCLUSION

Unsharp mask-image processing of digital chest radiography will not improve the detection rate of small peripheral lung cancer, probably due to a substantial drawback: the limited conspicuity of cancer lesions in the surrounding lung and superposition of structures.

Tuberculosis versus lymphomas in the abdominal lymph nodes: evaluation with contrast-enhanced CT

OBJECTIVE

Tuberculosis in the abdominal lymph nodes may be difficult to distinguish from lymphomas. This study evaluated specific CT imaging criteria for differentiating these entities.

MATERIALS AND METHODS

We retrospectively reviewed the anatomic distribution and CT enhancement patterns of disease in 69 patients, 26 (38%) with tuberculosis and 43 (62%) with untreated lymphomas involving abdominal lymph nodes. Of the patients with tuberculosis, five (19%) had disseminated disease and 21 (81%) had nondisseminated disease. Of the patients with lymphomas, 16 (37%) had Hodgkin's disease and 27 (63%) had non-Hodgkin's lymphoma.

RESULTS

Disseminated and nondisseminated tuberculosis involved predominantly lesser omental, mesenteric, anterior pararenal, and upper paraaortic lymph nodes. Lower paraaortic lymph nodes were involved more often in Hodgkin's disease (15 patients [94%]), non-Hodgkin's lymphoma (24 patients [89%]), and disseminated tuberculosis (five patients [100%]) than in nondisseminated tuberculosis (one patient [5%]). Mesenteric lymph nodes were involved more often in disseminated tuberculosis (four patients [80%]) and nondisseminated tuberculosis (11 patients [52%]) than in Hodgkin's disease (one patient [6%]) (p < .01). Anatomic distribution was not different between disseminated tuberculosis and non-Hodgkin's lymphoma. Tuberculous lymphadenopathy commonly showed peripheral enhancement, frequently with a multilocular appearance, whereas lymphomatous adenopathy characteristically showed homogeneous attenuation (14 patients [87.5%] with Hodgkin's disease and 19 patients [70%] with non-Hodgkin's lymphoma [p < .01]).

CONCLUSION

Our findings indicate that the anatomic distribution and specific enhancement patterns of lymphadenopathy seen on contrast-enhanced CT can be useful in differentiating between tuberculosis and untreated lymphomas of the abdominal lymph nodes.

[An epidemiological study on influenza pandemic]

A cross-sectional epidemiological study on "the relationship between five variables [Fish, Pig, Duck, Chicken and Integrated Fish Farming (IFF)] and influenza pandemic" was carried out in 697 disease surveillance spots in the rural areas of Shandong & Henan provides. Results suggested that ducks might have played an important role in the ecology of influenza. Pigs did not seem to be a greater culprit in ecology of influenza but gave the inconsistent view with the hypothesis that IFF could lead to human influenza pandemic.

[The relationship between integrated fish farming and human influenza pandemic]

The study was carried out for reviewing the hypothesis on the relationship between integrated fish farming (IFF) and human influenza A pandemic using study methods of longitudinal epidemiology, ecology and serology. Four rural villages with IFF, non-IFF and non-fish farming, selected from two provinces (Henan and Shandong of PRC) were investigated for the status about human influenza A epidemic and infections with human, duck, swine influenaz A viruses in those communities. The results put forward views on that there is no relation between IFF and the increase of incidence rate, infection rate and antibodies level to human influenza A virus. Duck may play an important role in the increase of infection rate to human influenza A viruses among human communities. Pigs seem not to play obvious role in the increase of infection rate to human influenza A viruses among human communities. Human, duck, swine influenza A viruses may spread among human duck and pigs communities interchangably.

Peritoneal reflections of left perihepatic region: radiologic-anatomic study

To clarify the anatomy of the peritoneal reflections of the left perihepatic region, the authors examined 95 cadavers. Thirty-eight were studied radiographically, 37 with sagittal dissection, and 20 with transverse dissection. In over 80% of the cadavers, the left triangular ligament of the liver separated the left suprahepatic space into anterior and posterior sections. The lesser omentum extended to the diaphragm, where its anterior layer reflected and continued as the posterior layer of the left triangular ligament. Thus, the posterior left suprahepatic space and the lesser sac were clearly separated by the lesser omentum and the stomach and over-lapped each other in three dimensions. The posterior left suprahepatic space was located anterosuperior to the lesser sac and in turn was continuous with the gastrohepatic space inferiorly. Carefully researched diagrams of both the midline sagittal and left parasagittal perihepatic spaces were developed. This information has clinical value when the radiologist is called on to drain a left perihepatic abscess.