Usefulness of concurrent reading using thin-section and thick-section CT images in subcentimetre solitary pulmonary nodules.

AIM: To evaluate the differences in the characterization and recommendation for follow-up of subcentimetre solitary pulmonary nodules (SSPNs) between 5 and 1mm section CT, and to compare the assessments generated by four radiologists MATERIALS AND METHODS: Five hundred and twenty-nine patients who had SSPNs on chest CT reconstructed using both 5 and 1mm sections were enrolled. Two image subsets of 5 and 1mm CT images of each nodule were interpreted independently by four radiologists. Nodule size, consistency (solid, partly solid, non-solid), the presence of calcification, and recommendations for follow-up were evaluated. If a non-calcified solid nodule was confirmed using CT, recommendation for follow-up was based on Fleischner Society guidelines. Data assessed by each radiologist were compared, and interobserver agreements were determined using the intraclass correlation coefficients and kappa value. RESULTS: Using 1mm CT images, the nodule sizes were significantly larger than on 5mm CT images (paired t-test, p<0.01). The presence of calcification and nodule consistency were significantly different between 5 and 1mm CT images (McNemar test for the presence of calcification, p<0.01; Wilcoxon signed test for nodule consistency, p<0.01). On 1mm CT images there was significantly higher agreement regarding nodule consistency than on 5mm CT (kappa=0.78 and 0.67, respectively). CONCLUSIONS: Concurrent use of thin-section and thick-section CT can provide more accurate nodule assessment and higher interobserver agreement in SSPN.

Effect of recruitment and body positioning on lung volume and oxygenation in acute lung injury model.

The mechanism of oxygenation improvement after recruitment manoeuvres or prone positioning in acute lung injury or acute respiratory distress syndrome is still unclear. We tried to determine the mechanism responsible for the effects of recruitment manoeuvres or prone positioning on lung aeration using a whole lung computed tomography scan in an oleic acid induced acute lung injury canine model. Twelve adult mongrel dogs were allocated into either the supine group (n=6) or the prone group (n=6). After the establishment of acute lung injury, three recruitment manoeuvres were performed at one-hour intervals. Haemodynamic and ventilatory variables, arterial blood gas analyses and CT scans of the whole lung were obtained 90 minutes after oleic acid injection and five minutes before and after each recruitment manoeuvre. Recruitment manoeuvres in the supine position improved oxygenation (P=0.025) that correlated with increase of the poorly- and well-aerated dorsal (dependent) lung volume (r=0.436, P=0.016). Prone positioning increased oxygenation (P=0.004) that also correlated with increase of the poorly- and well-aerated dorsal (nondependent) lung volume (r=0.787, P<0.001). However, the recruitment manoeuvre in the prone position had no effect on oxygenation despite an increase in ventral (dependent) lung volume. The increase in PaO2 after recruitment manoeuvres in the supine position or after prone positioning is related to the increase of the poorly- and well-aerated dorsal lung.

Determination of optimal timing window for pulmonary artery MDCT angiography.

OBJECTIVE: The purpose of our study was to determine the optimal timing window for pulmonary artery MDCT angiography. SUBJECTS AND METHODS: We prospectively studied 150 patients. Routine chest CT scans were acquired using 1.3 mL/kg of contrast medium (370 mg I/mL) that was injected at a fixed injection duration of 30 seconds, followed by a 10-second saline chase. To measure early contrast enhancement, sequential monitoring scans were obtained every 2 seconds over a fixed level of the main pulmonary artery 5 seconds after the start of the injection. Then helical diagnostic scans were obtained at three different predetermined scanning delays (group A, 25 seconds; group B, 35 seconds; and group C, 45 seconds after the start of the injection). Time-enhancement curves; time to reach 100 H, 200 H, and peak enhancement; and enhancement duration greater than 200 H of the pulmonary artery were measured from the monitoring scan. Contrast enhancements of the pulmonary artery and descending aorta and vascular artifacts were assessed from the diagnostic scan. RESULTS: Times to reach 100 H and 200 H at the pulmonary artery were mean 11 +/- 2.5 (SD) seconds and 16 +/- 3.0 seconds, respectively. Pulmonary artery enhancement duration of greater than 200 H was 25 +/- 2.7 seconds (only obtained in group C). Mean time to peak enhancement (335 +/- 62 H) at the pulmonary artery was 37 seconds. Mean enhancement measured on the diagnostic scan was 294 +/- 43 H, group A; 208 +/- 48 H, group B; and 157 +/- 15 H, group C for the pulmonary artery, and 240 +/- 42 H, group A; 277 +/- 49 H, group B; and 172 +/- 29 H, group C for the aorta (p < 0.01). Artifacts were noted in the superior vena cava (group A, 96.7%; group B, 18.3%; and group C, 0%) and in the subclavian vein (group A, 93.5%; group B, 38.7%; and group C, 0%), (p < 0.05). CONCLUSION: With our study protocol of a 30-second injection and 10-second saline flush, the optimal temporal window to achieve pulmonary artery enhancement greater than 200 H was from 16 seconds to 41 seconds after the start of the injection.

Chronic tuberculous empyema: relationships between preoperative CT findings and postoperative improvement measured by pulmonary function testing.

AIMS: To evaluate whether preoperative computed tomography (CT) findings correlate with postoperative improvements in forced vital capacity (FVC) and forced expiratory volume during 1s (FEV1) in persons who have undergone unilateral decortication because of unilateral chronic tuberculous empyema. METHODS: A retrospective study was carried out of 67 individuals who had undergone decortication because of chronic tuberculous empyema between January 1996 and December 2000. Of these, 13 subjects who had had preoperative chest CT and preoperative and postoperative pulmonary function tests (PFTs) were included in the investigation. On preoperative CT, the degree of volume reduction of the affected side was compared with that of the contralateral normal lung. The relative volume of empyema was calculated by dividing the volume occupied by the empyema by the sum of the total volume of the ipsilateral lung and the empyema volume. The thicknesses of pleura and extrapleural fat in the involved hemithorax were measured by CT at their thickest points, and the degree of atelectasis adjacent to the empyema in the diseased lung was assessed and classified. These five CT parameters and the ages of the patients were compared with preoperative and postoperative FVC and FEV1 changes. RESULTS: A significant negative correlation was found between FVC changes and the relative volume of the affected lung (FVC: p = 0.039, RS = -0.58). FVC and FEV1 were found to be significantly and positively correlated with the relative volume of the empyema (FVC: p = 0.005, RS = 0.72; FEV1: p = 0.014, RS = 0.66) and the degree of atelectasis (FVC: p = 0.007, RS = 0.71; FEV1: p = 0.029, RS = 0.60) by Spearman's nonparametric correlation test. Other CT parameters and the ages of the patients were not found to be correlated with PFT changes. CONCLUSION: The relative volume of the affected side, the relative volume of empyema and the degree of atelectasis can predict improvements in FVC and FEV1 after decortication in patients with chronic tuberculous empyema.

Comparison of contrast-enhanced ct angiography and gadolinium-enhanced MR angiography in the detection of subsegmental-sized pulmonary embolism. An experimental study in a pig model.

PURPOSE: To compare contrast-enhanced CT angiography (CTA) and gadolinium-enhanced MR angiography (MRA) for the detection of subsegmental-sized pulmonary emboli in a pig model. MATERIAL AND METHODS: In 5 anesthetized pigs, 3-mm diameter embolic materials made of Konjac, a semisolid food, were introduced through the internal jugular vein into pulmonary arteries. After embolization, CTA and MRA images were obtained. Respiration was suspended during CTA and MRA image acquisition. Two readers reviewed the CTA and MRA images to detect emboli. The pigs were sacrificed, and sliced specimens of inflated lung served as the gold standard. RESULTS: Thirty-six emboli were detected within peripheral arteries. The sensitivity (and 95% confidence intervals) of CTA for the two readers were 57% (39-74%) and 66% (48-81%), and 88% (69-98%) and 92% (74-94%) for MRA. The specificity of CTA was 95% (91-97%) and 98% (96-99%), and that of MRA was 85% (74-93%) and 90% (80-96%). Interobserver agreement was higher for MRA (kappa 0.898) than CTA (kappa 0.574). CONCLUSION: For the detection of subsegmental pulmonary emboli, MRA was superior to CTA, with a higher sensitivity and interobserver agreement by demonstrating perfusion deficits.

Subphrenic bronchogenic cyst mimicking a juxtahepatic solid lesion.

Most bronchogenic cysts occur in the mediastinum. However, they may be found near any organ derived from the embryonic foregut, even in the extrathoracic region. We report a case of subphrenic bronchogenic cyst that was initially confused with a solid lesion because of its unusual location and atypical appearance on ultrasonography, computed tomography, and magnetic resonance imaging.

Foreign bodies in the chest: how come they are seen in adults?

The radiologic and clinical findings of foreign bodies in the chest of children are well recognized. Foreign bodies in adults are infrequent, however, and the radiologic findings of these unusual circumstances have rarely been described. We classified various thoracic foreign bodies into three types according to their cause: Type I, Aspiration, Type II, Trauma or Accident; Type III, Iatrogenic. This pictorial essay will illustrate the radiologic findings and consequences of thoracic foreign bodies in adults, which have rarely been described in the radiologic literature. The clinical significance of thoracic foreign bodies will be also be discussed.

Coexisting bronchogenic carcinoma and pulmonary tuberculosis in the same lobe: radiologic findings and clinical significance.

OBJECTIVE: Bronchogenic carcinoma can mimic or be masked by pulmonary tuberculosis (TB), and the aim of this study was to describe the radiologic findings and clinical significance of bronchogenic carcinoma and pulmonary TB which coexist in the same lobe. MATERIALS AND METHODS: The findings of 51 patients (48 males and three females, aged 48-79 years) in whom pulmonary TB and bronchogenic carcinoma coexisted in the same lobe were analyzed. The morphologic characteristics of a tumor, such as its diameter and margin, the presence of calcification or cavitation, and mediastinal lymphadenopathy, as seen at CT, were retrospectively assessed, and the clinical stage of the lung cancer was also determined. Using the serial chest radiographs available for 21 patients, the possible causes of delay in the diagnosis of lung cancer were analyzed. RESULTS: Lung cancers with coexisting pulmonary TB were located predominantly in the upper lobes (82.4%). The mean diameter of the mass was 5.3 cm, and most tumors (n=42, 82.4%) had a lobulated border. Calcification within the tumor was seen in 20 patients (39.2%), and cavitation in five (9.8%). Forty-two (82.4%) had mediastinal lymphadenopathy, and more than half the tumors (60.8%) were at an advanced stage [IIIB (n=11) or IV (n=20)]. The average delay in diagnosing lung cancer was 11.7 (range, 1-24) months, and the causes of this were failure to observe new nodules masked by coexisting stable TB lesions (n=8), misinterpretation of new lesions as aggravation of TB (n=5), misinterpretation of lung cancer as tuberculoma at initial radiography (n=4), masking of the nodule by an active TB lesion (n=3), and subtleness of the lesion (n=1). CONCLUSION: Most cancers concurrent with TB are large, lobulated masses with mediastinal lymphadenopathy, indicating that the morphologic characteristics of lung cancer with coexisting pulmonary TB are similar to those of lung cancer without TB. The diagnosis of lung cancer is delayed mainly because of masking by a tuberculous lesion, and this suggests that in patients in whom a predominant or growing nodule is present and who show little improvement of symptoms despite antituberculous or other medical therapy, coexisting cancer should be suspected.

Idiopathic multilocular thymic cyst: CT features with clinical and histopathologic correlation.

OBJECTIVE: We performed this study to describe the CT features of idiopathic multilocular thymic cysts with clinical and histopathologic correlation. CONCLUSION: Multilocular thymic cysts typically manifest on CT as unilocular or multilocular cystic thymic masses, often with soft-tissue attenuation components. CT cannot be used to distinguish neoplastic from nonneoplastic soft-tissue components.

Systemic arterial supply to the lungs in adults: spiral CT findings.

Systemic arterial supply to the lungs can be congenital or due to acquired disease. Congenital diseases encompass bronchopulmonary sequestration and congenital pulmonary venolobar syndrome, in which the involved lung parenchyma is supplied by the aberrant systemic arteries. An anomalous systemic artery can also supply an area of otherwise normal lung parenchyma. In acquired diseases, hypertrophied normal systemic arteries supply the lungs. Hypertrophied systemic arteries include the bronchial arteries, intercostal arteries, internal mammary arteries, inferior phrenic arteries, branches of the thyrocervical trunk, branches of the hepatic arteries, and branches of the abdominal aorta. Hypertrophy of normal systemic arteries is encountered in patients with bronchiectasis, pulmonary tuberculosis, other pulmonary infections, pulmonary thromboembolism, or chronic obstructive pulmonary disease. These systemic arteries are considered to supply the lungs by means of anastomoses between bronchial and pulmonary arteries within the lung parenchyma or transpleural systemic-pulmonary artery anastomoses. In most cases, the correct diagnosis and treatment plan can be determined by identification of the systemic arteries on computed tomographic scans.

Atypical pulmonary metastases: spectrum of radiologic findings.

Typical radiologic findings of a pulmonary metastasis include multiple round variable-sized nodules and diffuse thickening of interstitium. In daily practice, however, atypical radiologic features of metastases are often encountered that make distinction of metastases from other nonmalignant pulmonary diseases difficult. A detailed knowledge of the atypical radiologic features of a pulmonary metastasis with a good understanding of the histopathologic background is essential for correct diagnosis. Squamous cell carcinoma is regarded as the most common cell type of a cavitating metastasis, but metastatic nodules from adenocarcinomas and sarcomas also cavitate occasionally. Calcification can occur in a metastatic sarcoma or adenocarcinoma, which makes differentiation from a benign granuloma or hamartoma difficult. Peritumoral hemorrhage results in areas of nodular attenuation surrounded by a halo of ground-glass opacity. Pneumothorax commonly occurs in metastases from an osteosarcoma. Air-space consolidation is often seen in cases of metastases from gastrointestinal tract malignancies. Even though tumor emboli in pulmonary arteries can be seen at computed tomography, diagnosis is difficult because they are located in small or medium arteries. A common radiologic appearance of an endobronchial metastasis is an atelectasis. In cases of an endobronchial or a solitary pulmonary metastasis, differentiation between bronchogenic carcinoma and metastasis is difficult. Dilated vascular structures within the mass can be seen in metastatic sarcomas. A sterilized metastasis after chemotherapy is radiologically indistinguishable from a residual viable tumor. Benign tumors such as uterine leiomyomas and giant cell tumors of the bone rarely metastasize to the lung.

US of mammographically detected clustered microcalcifications.

PURPOSE: To determine whether ultrasonography (US) can depict breast masses associated with mammographically detected clustered microcalcifications and whether the visibility at US is different between benign and malignant lesions. MATERIALS AND METHODS: Ninety-four patients with 100 mammographically detected microcalcification clusters prospectively underwent US with a 10- or 12-MHz transducer before mammographically guided presurgical hook-wire localization. The visibility of breast masses at US was correlated with histologic and mammographic findings. RESULTS: Surgical biopsy revealed 62 benign lesions, 30 intraductal cancers, and eight invasive cancers. At US, breast masses associated with microcalcifications were seen in 45 (45%) of 100 cases. US depicted more breast masses associated with malignant (31 [82%] of 38) than with benign (14 [23%] of 62) microcalcifications (P: <.001). In malignant microcalcification clusters larger than 10 mm, US depicted associated breast masses in all 25 cases. There was no statistically significant difference in shape and distribution of calcific particles, as well as in breast composition, at mammography between US visible and invisible groups. CONCLUSION: Given a known mammographic location, US with a high-frequency transducer can depict breast masses associated with malignant microcalcifications, particularly clusters larger than 10 mm. US can be used to visualize large clusters of microcalcifications that have a very high suspicion of malignancy.

Renal and pulmonary lymphangioleiomyomatosis: a case report.

Lymphangioleiomyomatosis (LAM) is a rare disease that most commonly involves the lung. However, extrapulmonary lymphangioleiomyomatosis rarely occurs with or without subsequent involvement of the lung. We report a case of incidentally found renal and pulmonary lymphangioleiomyomatosis in a patient who had no stigmata of tuberous sclerosis.

Nonpalpable breast lesions: evaluation with power Doppler US and a microbubble contrast agent-initial experience.

PURPOSE: To evaluate power Doppler ultrasonography (US) performed with a microbubble US contrast agent in the differentiation of nonpalpable breast lesions. MATERIALS AND METHODS: Fifty nonpalpable breast lesions in 50 patients were prospectively evaluated with power Doppler US before and after injection of the contrast agent SH U 508A. Lesion vascularity and the morphology of vessels on US scans were analyzed and were correlated with histologic results. RESULTS: Surgical excision revealed 22 cancers and 28 benign lesions. At nonenhanced power Doppler US, eight (36%) of 22 cancers and four (14%) of 28 benign lesions were vascular. At contrast agent-enhanced power Doppler US, 21 (95%) cancers and six (21%) benign lesions were vascular (P <.001). Irregular vessels were seen in three cancers and one benign lesion at nonenhanced power Doppler US and in 11 cancers and one benign lesion at contrast-enhanced power Doppler US. By using the presence of vascularity in the mass as the diagnostic criterion for malignancy, the sensitivity, specificity, and positive and negative predictive values of power Doppler US changed from 36%, 86%, 67%, and 63%, respectively, to 95%, 79%, 78%, and 96% after contrast agent injection. CONCLUSION: Contrast-enhanced power Doppler US was superior to nonenhanced power Doppler US in the demonstration and characterization of tumor vascularity in nonpalpable breast lesions. Contrast-enhanced power Doppler US may be useful for the differentiation between nonpalpable breast cancers and benign tumors.

Digital chest radiography with a selenium-based flat-panel detector versus a storage phosphor system: comparison of soft-copy images.

OBJECTIVE: We compared the soft-copy images produced by a digital chest radiography system that uses a flat-panel X-ray detector based on amorphous selenium with images produced by a storage phosphor radiography system for the visualization of anatomic regions of the chest. MATERIALS AND METHODS: Two chest radiologists and two residents analyzed 46 pairs of posteroanterior chest radiographs on high-resolution video monitors (2560 x 2048 x 8 bits). In each pair, one radiograph was obtained with a storage phosphor radiography system, and the other radiograph was obtained with a selenium-based flat-panel detector radiography system. Each pair of radiographs was obtained at the same exposure settings. The interpreter rated the visibility and radiographic quality of 11 different anatomic regions. Each pair of images was ranked on a five-point scale (1 = prefer image A, 3 = no preference, 5 = prefer image B) for preference of technique. Statistical significance of preference was determined using the Wilcoxon's signed rank test. RESULTS: The interpreters had a statistically significant preference for the selenium-based radiography system in six (unobscured lung, hilum, rib, minor fissure, heart border, and overall appearance) of 11 anatomic regions (p<0.001) and for the storage phosphor system in two regions (proximal airway and thoracic spine) (p<0.05). Chest radiologists strongly preferred selenium-based images in eight regions, and they did not prefer storage phosphor images in any region. CONCLUSION: The soft-copy images produced by the selenium-based radiography system were perceived as equal or superior to those produced by the storage phosphor system in most but not all anatomic regions.

Pseudochylous pleural effusion with fat-fluid levels: report of six cases.

The authors report the clinical and computed tomographic (CT) findings in six patients with chyliform pleural effusion. All six patients had a medical history of pleurisy before presentation; five of them had tuberculous pleural effusion. The CT scans of all six patients showed variable amounts of pleural fluid collection with a layering of fat at the nondependent site.

Pulmonary tuberculoma evaluated by means of FDG PET: findings in 10 cases.

PURPOSE: To describe findings of pulmonary tuberculoma at 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET). MATERIALS AND METHODS: Ten consecutive patients who underwent PET and subsequently were proved to have pulmonary tuberculoma were analyzed. Tuberculosis was proved histopathologically in eight by means of wedge resection or lobectomy (n = 7) or needle biopsy (n = 1) and in two by means of clinical follow-up for more than 2 years. PET scans were evaluated by using peak standardized uptake values. Computed tomographic (CT) and histopathologic findings also were reviewed. RESULTS: Nine of 10 tuberculomas showed FDG uptake at PET, and the mean peak standardized uptake value was 4.2 +/- 2.2 (SD). FDG uptake (range, 1. 9-3.7) in lesions adjacent to main abnormalities was demonstrated in four patients. On CT scans, the mean of the longest nodule diameters was 21 mm +/- 8, and there were some areas of branching linear opacities or satellite nodules that suggested pulmonary tuberculosis in seven patients. Histopathologic findings were chronic granulomatous inflammation with caseation necrosis (n = 7) and healed tuberculosis with aspergilloma (n = 1). CONCLUSION: Pulmonary tuberculoma commonly causes an increase in FDG uptake. These results suggest that in geographic regions with a high prevalence of granulomatous lesions, positive FDG PET results should be interpreted with caution in differentiating benign from malignant pulmonary abnormalities.

Dynamic contrast-enhanced MR imaging of bacterial abscess and VX2 carcinoma in rabbits: comparison of gadopentetate dimeglumine and a macromolecular contrast agent.

OBJECTIVE: The objective of this study was to compare enhancement patterns of a blood-pool contrast agent, Gadomer-17, with those of gadopentetate dimeglumine in bacterial abscesses and VX2 carcinoma in rabbits. MATERIALS AND METHODS: Fourteen rabbits with experimentally induced bacterial abscesses and VX2 carcinoma in both thighs underwent dynamic contrast-enhanced MR imaging with Gadomer-17 and gadopentetate dimeglumine at a 24-hr interval. The enhancement ratios (postcontrast to precontrast signal intensities) of lesions in the same animal were assessed and correlated with microvessel density. RESULTS: For Gadomer-17, the enhancement ratio of the abscesses (1.66 +/- 0.39) peaked 15 min after the injection, while that of the carcinoma (2.05 +/- 0.16) peaked at 10 min. The enhancement ratios of the carcinoma were consistently higher than those of the abscesses up to 30 min. For gadopentetate dimeglumine, peak enhancement ratio of the abscesses (2.30 +/- 0.75) was seen 5 min after the injection, while that of the carcinoma (2.32 +/- 0.51) was seen at 3 min. The enhancement ratios of the carcinomas were significantly higher at 1 min, but significantly lower at 20-30 min, compared with those of the abscesses, as a result of rapid decrease of enhancement ratios in the carcinomas. The microvessel density was 9.8 +/- 5.2 vessels per field of view for the abscesses and 36.3 +/- 9.5 vessels per field of view for the carcinoma (p < 0.001). CONCLUSION: Delayed peak enhancement and slow decay were found in both bacterial abscess and VX2 carcinoma with Gadomer-17, whereas early peak enhancement and rapid decay were found especially in VX2 carcinoma with gadopentetate dimeglumine. Enhancement ratios on MR imaging with a blood-pool contrast agent correlated well with the microvessel density in bacterial abscess and VX2 carcinoma.