CT evaluation of pulmonary metastases: usefulness in comparison with chest radiography

The purpose of this study was to evaluate the usefulness of follow-up CT for screening pulmonary metastases, in comparison with chest radiography (CXR). Two hundred sixty CT examinations performed on 200 patients with known malignancy formed the basis of the study. One hundred sixty-five metastatic nodules were detected from 52 CT examinations in 36 patients. The detectability of these nodules on CXR was relatively good, but it was better on CT, which detected more nodules of smaller size, those overlying the mediastinum or hilus, and those showing ground-glass attenuation. As for the relationship between treatment and pulmonary metastases, pulmonary metastases treated surgically were detected on CXR in all patients. Pulmonary metastases showed a tendency to recur within one year after the initial treatment. The author concluded that routine CT to screen occult lung metastases in every patient with malignancy is not cost-effective. However, CT may be added at the start of the initial treatment and within one year thereafter, particularly for patients with lung cancer.     

Renal involvement in children with lymphoma: comparison of CT with sonography

In order to determine whether real-time sonography or contrast-enhanced CT was better for detecting renal involvement by lymphoma in children, we retrospectively studied 44 patients (6 months to 19 years of age) in whom lymphoma was diagnosed at our hospital during a 5-year period. In no patient was there any clinical evidence of renal disease at the time of presentation. In 39 patients, sonographic and CT findings were similar (normal in 36 patients and showing extrinsic mass effects on the kidneys in three patients). In five patients with non-Hodgkin lymphoma whose contrast-enhanced CT scans showed low-attenuation renal nodules, renal sonography was normal in two, showed renal enlargement in two, and showed a solitary hypoechoic nodule in one patient with multiple, bilateral nodules on CT. Tissue diagnosis of the renal lesions was not obtained, but in the four patients who had follow-up CT, the renal abnormalities resolved after chemotherapy. Our findings suggest that contrast-enhanced CT is superior to sonography for detection of renal lymphoma in children.     

The variable nature of the mediastinal contour lines: CT/chest radiography correlation

Interfacing of the lung with the mediastinum produces a number of mediastinal lines including those due to the innominate veins, left subclavian artery, paratracheal stripe, both anterior and posterior junction lines, the azygo-esophageal recess, descending aorta and paraspinal lines. Displacement or absence of one or more of these lines may be due to an abnormality of mediastinal contour or may indicate a mediastinal mass, but can occur in normal subjects. Correlative findings between chest radiography and chest computed tomography in 50 normal subjects illustrate the variable nature of these lines.     

Asbestos-related pleural disease and asbestosis: a comparison of CT and chest radiography

High-resolution CT (HRCT) has the ability to demonstrate both asbestos-related pleural disease and parenchymal abnormalities consistent with asbestosis. The role of CT in the diagnosis of asbestosis can be defined by comparing it with radiography. We evaluated 60 men who had a history of occupational exposure to asbestos and whose outside chest radiographs were considered abnormal. Chest radiographs (inside films) and HRCT were performed in all patients at our institution and were interpreted independently by experienced radiologists. Outside film results were compiled from the submitted reports. The final conclusion regarding the interpretation of the radiologic examinations was determined by consensus when disagreements existed. Positive predictive values (the likelihood that a positive report is correct) for pleural disease were: outside films 56%, inside films 79%, HRCT 100%. The positive predictive values for parenchymal disease were: outside films 51%, inside films 83%, HRCT 100%. The addition of HRCT to chest radiography is most useful in eliminating false-positive diagnoses of asbestos-related pleural disease caused by subpleural fat and false-positive diagnoses of parenchymal asbestosis in patients with extensive plaques or emphysema obscuring lung detail. The interpretation of chest radiographs in patients exposed to asbestos is often extremely difficult and subjective, and we recommend that positive findings (except calcified plaques) be confirmed with HRCT.     

Value of conventional chest radiography for the detection of coronary calcifications: comparison with MSCT

Purpose

To evaluate if computed tomography (CT) coronary calcium scoring is needed after detection of coronary calcifications on conventional chest radiographs.

Materials and methods

One hundred and five patients (67 men; 57.2 ± 12.8 years) with suspected coronary artery disease underwent conventional chest radiography and non-enhanced, retrospectively ECG-gated multislice spiral CT (MSCT) of the heart (4 mm × 2.5 mm, 120 kV, 133 mAs_eff.). Chest radiographs were assessed independently by two radiologists. Detection of coronary calcifications was compared between both methods. Sensitivity, specificity, negative and positive predictive values, median, 25% and 75% percentiles for the detection of coronary calcifications were calculated. Receiver operating characteristics (ROC) analyses were computed.

Results

In 90 patients, MSCT revealed coronary calcifications. The mean coronary calcium score was 526.2 (0–4784.5). On chest radiographs, coronary calcifications were correctly detected in 46 (61) patients by observer 1 (observer 2). The corresponding sensitivity was 51.1% in observer 1 and 67.8% in observer 2. Median of detected coronary calcifications was 361.9 (426.4) for observer 1 (observer 2). Corresponding 25% und 75% percentiles were 109.6 (109.6) and 798.5 (898.5). The area under the ROC curve was 0.636 for observer 1 and 0.715 for observer 2. There was no correlation between image quality and the detection of coronary calcifications on plain film radiographs.

Conclusion

As coronary calcifications of various extents are inconsistently detected on plain chest radiographs, CT calcium scoring may not be omitted even if coronary artery calcifications were detected on conventional chest radiographs.     

Intrafissural fat: CT correlation with chest radiography

A small collection of supradiaphragmatic fat is occasionally present invaginating into the inferior aspect of the major interlobar fissure. In a review of 212 computed tomography (CT) scans obtained in the immediate supradiaphragmatic region, 39 cases demonstrated some degree of this intrafissural fat collection either unilaterally or bilaterally. On lateral chest radiographs, the intrafissural fat corresponded to a sharply marginated triangular density, the base of which abutted the anterior diaphragmatic surface and the apex of which tapered into the major fissure. The triangular density seen on the chest radiographs was superimposed over the heart and cardiac fat pad but was always easy to distinguish from these owing to the continuity of the density with the oblique fissure.     

Mediastinal tumors: sensitivity of detection with sonography compared with CT and radiography

The purpose of this prospective study was to evaluate the sensitivity of mediastinal sonography compared with computed tomography (CT) and chest radiography in the detection of mediastinal tumors. The sonograms, CT scans, and chest radiographs of 182 patients were interpreted blindly by three observers, and the results were compared. The proportion of diagnostic sonographic examinations varied for the different mediastinal compartments from 85% (subcarinal region) to 96% (supraaortic region). The sensitivities of sonography and chest radiography, respectively, for each compartment, with CT as the reference method, were as follows: supraaortic region, 98% and 67%; paratracheal region, 89% and 69%; aorticopulmonary window, 81% and 62%; prevascular region, 92% and 46%; subcarinal region, 69% and 31%; pericardial region, 100% and 67%; posterior mediastinum, 6% and 6%; and paravertebral region, 11% and 44%. These results show that sonography is superior to chest radiography in the diagnosis of mediastinal tumors. In certain mediastinal regions (supraaortic, pericardial, prevascular, and paratracheal), sonography is so sensitive that CT and magnetic resonance examinations may be obviated in patients with equivocal radiographic findings.     

气管-支气管结核的胸部X线与CT诊断

目的 了解气管-支气管结核的胸部X线与CT征象及其诊断价值。方法 36例气管-支气管结核患，其中临床证实16例，手术病理证实20例，均经胸部X线与CT检查，对全部患的胸部X线与CT表现进行了回顾性分析。结果 36例患中，胸部X线显示肺段叶及全肺不张12例，两肺结核性病灶18例，其中有陈旧性结核灶，粟粒播散灶，浸润灶及肺门淋巴结肿大。病变支气管表现有完全性支气管阻塞10例，支气管肺内结节状突起5例；胸部CT扫描显示支气管管腔变窄伴管壁增厚25例，管腔表面凹凸不平5例。管腔内有结节状突起6例，纵隔淋巴结肿大及钙化15例。结论 对气管-支气管结核的胸部X线与CT表现进行综合分析。大大有助于提高其诊断准确性。     

Chronic diffuse infiltrative lung disease: comparison of diagnostic accuracy of CT and chest radiography

The accuracies of chest radiography and computed tomography (CT) in the prediction of specific diagnoses in 118 consecutive patients with chronic diffuse infiltrative lung disease (DILD) were compared. The radiographs and CT scans were independently assessed by three observers without knowledge of clinical or pathologic data. The observers listed the three most likely diagnoses in order of probability and recorded the degree of confidence they felt in their first-choice diagnosis on a three-point scale. Confidence level 1 (definite) was reached with 23% of radiographic and 49% of CT scan readings, and the correct diagnosis was made with 77% and 93% of those readings, respectively (P less than .001). The correct first-choice diagnosis regardless of the level of confidence was made with 57% of radiographic and 76% of CT scan readings (P less than .001). The CT scan interpretations were most accurate in silicosis (93%), usual interstitial pneumonia (89%), lymphangitic carcinomatosis (85%), and sarcoidosis (77%). Observers correctly predicted whether a transbronchial or open lung biopsy was indicated with 65% of radiographs and 87% of CT scans (P less than .001). It is recommended that CT be performed before lung biopsy in all patients with chronic DILD.     

Is chest CT sufficient for follow-up of primary mediastinal B-cell lymphoma in remission?

OBJECTIVE: We aimed to evaluate whether chest CT alone is sufficient for follow-up assessment of patients with primary mediastinal B-cell lymphoma that is in remission. MATERIALS AND METHODS: A retrospective review of medical records and CT examinations of patients who received a diagnosis of primary mediastinal B-cell lymphoma between January 1989 and January 2000 was performed. The first-year follow-up comprised examinations at 3-month intervals of the neck, chest, abdomen, and pelvis, with the examination modality alternating between CT and gallium scintigraphy. Patients who achieved complete remission underwent the same CT protocol twice the following year and then once a year during sequential follow-up. RESULTS: Fifty-three patients with primary mediastinal B-cell lymphoma at presentation--31 females and 22 males, ranging in age from 17 to 61 years (average age at diagnosis, 34 years)--were studied. The follow-up time ranged from 6 to 143 months (average follow-up time, 42.4 months). Although 11 of the patients had only a partial remission, 42 patients (79%) achieved complete remission, with one patient lost to follow-up and thus excluded from study. Recurrence was diagnosed in six of these 42 patients. All six had mediastinal recurrence with additional involvement of the lungs, chest wall, pericardium, and pleura. One patient also had bone marrow involvement at recurrence. CONCLUSION: Recurrence of primary mediastinal B-cell lymphoma in patients who achieve complete remission appears to be confined to the chest. Consequently, chest CT alone is sufficient for routine follow-up of these patients.     

Efficacy of digital radiography for the detection of pneumothorax: comparison with conventional chest radiography.

As part of our continuing evaluation of the clinical applicability of digital radiography, we compared the abilities of radiologists to detect pneumothoraces on conventional chest radiographs with their performances when using three formats of digitally obtained images. Twenty-three frontal-view chest radiographs with pneumothoraces and 22 other chest radiographs, either normal or showing miscellaneous abnormalities, were interpreted by five experienced radiologists in each of four formats: conventional film-screen chest radiographs, small-format (17.8 x 21.6 cm) computed radiographs, large-format (35.6 x 43.1 cm) computed radiographs, and digital images viewed on an interactive electronic workstation. The receiver-operating-characteristic curve areas for each observer for the four types of images were compared by a z test on a critical ratio, and the mean sensitivity and specificity values were compared by the sign rank test. The mean areas under the receiver-operating-characteristic curves ranged from 0.869 for the digital workstation to 0.915 for film-screen images. The differences observed among formats were not statistically significant. Mean specificities also were not significantly different, ranging from 0.90 for large-format computed radiographs to 0.96 for the digital workstation. Mean sensitivity ranged from 0.65 for the digital workstation to 0.82 for film-screen images. Radiologists interpreting digital workstation images were significantly less sensitive in detecting pneumothoraces than with film-screen and small-format computed images (p = .06). In this study, radiologists detected pneumothoraces equally well on conventional film-screen radiographs and digital images printed on film; however, they detected pneumothoraces less well on electronic viewing consoles. This latter finding reflects an important practical difference in the working behavior of radiologists interacting with a digital workstation.     

Chest radiography and computed tomography in the evaluation of mediastinal adenopathy in lymphoma

Thoracic computed tomography (CT) in 232 patients with either primary staging of new or suggested relapsing lymphoma was compared with conventional chest radiography and both were correlated with clinical staging. Particular attention was given to the possibility of reducing routine thoracic CT, which is the current method used in this hospital in all patients with suggested lymphoma. Mediastinal lymphoma was detected by CT in 95 per cent of patients with clinically active mediastinal lymphoma, and by conventional chest radiography in 56 per cent. CT was found to be less reliable in evaluation of the hilar region than in that of other mediastinal areas. No areas of particular difficulty were found with chest radiography. CT also provided additional information concerning extra-mediastinal lymph adenopathy and involvement of the thoracic wall and pericardium. Routine thoracic CT examination was considered justifiable in all patients with suggested lymphoma.     

350 kVp chest radiography: review and comparison with 120 kVp.

High kilovoltage radiography had its beginning with super-voltage technique and is presently accomplished with the 350 KV chest x-ray system. The physical reasons to explain the improved visibility with this technique are: (1) absorption coefficients of bone and soft tissue, (2) more uniform bone visibility, (3) x-ray spectrum, (4) visual responses, and (5) depth resolution. In this study, 350 kV and 120 kV chest x-ray techniques were compared by evaluating 15 parameters. Based on our data and the results of previous large clinical studies, a list of disadvantages and advantages is offered. The entrance dose for an average 350 kV posteroanterior chest radiograph is 8 mR, or about one-third that with 90 kV technique.     

Portable chest radiography in intensive care: a comparison of computed and conventional radiography.

A prospective study was performed comparing computed and conventional radiography for the detection and visibility of cardiovascular devices in intensive care unit patients. Computed images were obtained using a commercially available 2K x 2K, 12-bit storage phosphor plate system. Image sets from 50 patients were assessed independently by three observers. A significant difference between the types of image was found for the detection of mediastinal drainage tubes and prosthetic valves. Computed images allowed greater confidence in the identification of courses and tips of lines. This advantage was most marked with edge-enhanced computed images.     

Digital chest radiography with a large-area flat-panel silicon X-ray detector: clinical comparison with conventional radiography

This was a radiologists' preference study to compare a digital chest radiography system that utilizes a large-area silicon flat-panel detector with conventional radiography for visualizing anatomic regions of the chest. Conventional and digital posteroanterior (PA) and lateral chest radiographs were obtained in 115 patients. The PA and lateral image pairs were compared independently by three radiologists rating the overall appearance, 11 anatomic regions in the PA, and 9 in the lateral views. Statistical analysis was performed with the Wilcoxon signed-rank test with Bonferroni-Holm adjustment (p=0.05). For the PA view, the digital system performed significantly better for the overall appearance and for all anatomic regions except for the peripheral pulmonary vasculature and hilum, where no significant difference was found. For the lateral digital images, the regions trachea, costodiaphragmatic recess, and hilum were rated significantly worse. The regions retrosternal and retrocardiac lung were rated significantly better. The other regions and the overall appearance showed no significant differences. The described digital chest radiography system showed statistically superior visualization of anatomic regions for PA and an ambiguous performance for lateral images as compared with conventional radiography. After changing some image processing parameters for the lateral view, this system may be suitable for digitalization of chest radiography.     

PET/CT in initial staging and therapy response assessment of early mediastinal lymphoma

Objective

To detect accuracy of PET/CT in the initial staging, response after the first line and end of treatment in early mediastinal lymphoma patients compared to contrast CT.

Materials and methods

We studied 50 patients with pathologically proven lymphoma with a mean age = 27.5. All patients were at early stage. All patients performed CT and PET/CT for initial staging, after the first course of chemotherapy (after 4–6 weeks) and at the end of treatment (after 2–4 months).

Results

PET/CT upstaged 5 cases. At first line of treatment, PET/CT and CECT were agreeable in 32% of cases. PET/CT showed 100% sensitivity, 96.7% specificity, 95% positive predictive value and 100% negative predictive value. At the end of treatment both methods showed a 46% agreement. PET/CT was statistically significant in the follow up of hilar and axillary lymph nodes. PET/CT showed 100% sensitivity and specificity; compared to 62.5% sensitivity and 97.6% specificity for CECT in detection of extra-nodal disease sites.

Conclusion

PET/CT proved higher sensitivity and specificity over CECT. The major strength of PET/CT over CECT was its higher ability for detection of extra-nodal sites of lymphoma and excluding active disease in residual nodal mass lesions on follow up.