An analysis of the left top pulmonary vein and comparison with the right top pulmonary vein for lung resection by three-dimensional CT angiography and thin-section images.

PURPOSE: The right top pulmonary vein (RTPV) is defined as an anomalous branch of the right superior PV (SPV) draining into the PV or left atrium (LA). Several previous reports have described the RTPV, but only a few have mentioned the left top PV (LTPV). The present study aimed to evaluate the branching patterns of the RTPV and LTPV using thin-section CT images and three-dimensional CT angiography (3D-CTA). MATERIALS AND METHODS: This study included 1437 consecutive patients for evaluation of the right side and 1454 consecutive patients for the left side who were suspected of lung cancer and underwent CTA. We assessed the presence of each RTPV and LTPV and their branching patterns on the CTA images. When the RTPV or LTPV was identified, the maximum short-axis diameter was measured. RESULTS: RTPV was found in 9.1% (131/1437), whereas LTPV was found in 2.9% (42/1454) of the patients. RTPV was also observed in 17.1% (7/41) of LTPV cases, except for one case in which the right side could not be evaluated. The most common RTPV inflow site was the right inferior PV (IPV) in 64.9% (85/131) of the patients, whereas that of the LTPV was the left IPV in 100.0% (42/42) of the patients. The mean diameter of the RTPV and LTPV was 3.3 mm (range, 1.3-7.5 mm) and 2.4 mm (range, 0.9-6.3 mm), respectively (P < 0.01). CONCLUSION: The top PV branching pattern variations can be evaluated using thin-section CT and 3D-CTA images. RTPV is not a rare finding, and LTPV should also be identified in lung cancer cases scheduled for resection.

An analysis of anatomical variations of the left pulmonary artery of the interlobar portion for lung resection by three-dimensional CT pulmonary angiography and thin-section images.

PURPOSE: The purpose of the present study was to analyze the left pulmonary artery (LPA) branching pattern of the interlobar portion using three-dimensional CT pulmonary angiography (3D-CTPA) and thin-section CT images, and to attempt to diagrammatize these patterns. MATERIALS AND METHODS: The study included 320 patients suspected of having lung cancer of the left upper/lower lobe who underwent CTPA. The number and origin of the LPA branches of the interlobar portion, A1 + 2c, A6, and lingular artery from pars interlobaris (PI), were identified meticulously using 3D-CTPA and thin-section images. We then diagrammatized the identified LPA branching patterns of the interlobar portion. RESULTS: The diagrammatized LPA branching patterns of the interlobar portion were broadly classified into seven types in the order of bifurcation from proximal to distal. Type 1 was the most frequent (120/320, 37.5%). PI originated from the lower portion, that is, from A8 or the common trunk of A8 and A9 in 95 cases (29.7%). We could also precisely diagrammatize the LPA branching patterns of the interlobar portion into 85 types in all 320 patients. CONCLUSION: 3D-CTPA and thin-section images provided precise preoperative information regarding the LPA branching patterns of the interlobar portion.

Preoperative Evaluation of the Right Upper Lobe Pulmonary Artery by 3D-CT Pulmonary Angiography vs. Thin-Section Multiplanar Reconstruction Images Obtained by Contrast-Enhanced Multidetector-Row CT.

We compared the effectiveness of 3-dimensional computed tomography pulmonary angiography (3D-CTPA) and thin-section multiplanar reconstruction (MPR) images obtained using contrast-enhanced multidetector row CT (MDCT), in the evaluation of pulmonary artery (PA) branches of the right upper lobe. We studied 127 patients suspected of having lung cancer of the right upper lobe who underwent contrast-enhanced MDCT scans and a right upper lobectomy. We compared the intraoperative findings of the PA branches of the right upper lobe obtained with 3D-CTPA and thin-section MPR images. In 125 (97.7%) patients, one or more PA branches arose from arteries other than the superior trunk. Among 10 (7.9%) patients, a PA branch arose from the middle lobe in one patient and from the superior segment of the lower lobe in the other 9 patients. According to the intraoperative findings, 97.2% and 99.7% of the PA branches were identified by 3D-CTPA and thin-section MPR images, respectively (p ＜ 0.03). The single branch missed by both imaging modalities was 1.0mm in dia. The 8 branches missed only by 3D-CTPA were ＜ 1.4mm in dia. Both the 3D-CTPA and thin-section MPR images provided precise preoperative information regarding PA branches of the right upper lobe. However, the thin-section MPR images appeared to contribute more to the evaluation of smaller PA branches.

Comparison of chest computed tomography features in the acute phase of cardiogenic pulmonary edema and acute respiratory distress syndrome on arrival at the emergency department.

PURPOSE: Discriminating cardiogenic pulmonary edema (CPE) from acute respiratory distress syndrome (ARDS) is a serious problem in emergency departments, and the ability of chest radiographs to differentiate between these 2 entities is limited. We compared the chest computed tomography (CT) findings in the acute phase of CPE with those of ARDS. MATERIALS AND METHODS: Outpatients with acute respiratory failure presenting to emergency departments with bilateral pulmonary opacities were enrolled. The patients included not only those who visited our hospital first but also those referred from other hospitals. Two intensivists who were blinded to the results of the chest imaging studies reviewed the patients' clinical records independently in order to determine a diagnosis of CPE or ARDS, and the chest CT findings were independently evaluated by 2 radiologists who were unaware of the patients' clinical information. The positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of the statistically different findings were calculated using standard definitions. RESULTS: Forty-one patients with CPE and 20 patients with ARDS were assessed. Upper-lobe-predominant ground-glass attenuation, central-predominant ground-glass attenuation, and central airspace consolidation were associated with high PPVs (95.2%, 92.3%, and 92.0%, respectively) and moderate NPVs (47.5%, 51.4%, and 50.0%, respectively) to diagnose as CPE. Left-dominant pleural effusion and small ill-defined opacities revealed relatively high PPVs (71.4% and 58.3%, respectively) and NPVs (72.2% and 73.5%, respectively) to diagnose as ARDS. The overall accuracy of the diagnosis by chest CT was 88.5% (54/61). CONCLUSIONS: Chest CT may be a useful tool for differentiating CPE from ARDS in the emergency department setting.

Relationship between CT findings and the plasma levels of brain natriuretic peptide in 29 patients with acute cardiogenic pulmonary edema.

RATIONALE AND OBJECTIVES: Brain natriuretic peptide (BNP) is a useful biomarker for the assessment of cardiogenic pulmonary edema. This study evaluated the relationship between computed tomography (CT) findings and plasma BNP levels in patients with cardiogenic pulmonary edema. MATERIALS AND METHODS: Twenty-nine consecutive outpatients with severe respiratory failure from cardiogenic edema presenting to emergency departments were enrolled. They underwent chest CT and plasma BNP levels were measured in the emergency room. CT findings were independently evaluated by two radiologists who were unaware of the patients' clinical information. RESULTS: The plasma BNP levels only correlated with the volume of pleural effusion in each side (right: r(s) = 0.519, P = .004; left: r(s) = 0.460, P = .012). No significant correlation was observed between the BNP levels and the findings of lung parenchyma or cardiovascular enlargement. CONCLUSION: Estimating the pleural effusion volume with CT may be a feasible method as well as measuring the plasma BNP level in the assessment of acute cardiogenic pulmonary edema.

[New parameters "average flow" and "acceleration wave": comparison with current parameters in the flow volume curve].

AIM: The flow volume curve is an essential test method for diagnosis and treatment of the respiratory diseases. However, this curve depends on patient's continuous effort toward optimal expiration and it has been reported that differences in this effort may possibly result in error in flow speed. To overcome the potential error, we devised the "average flow" and the "acceleration wave" that comprehends the overall data of the expiration flow speed, and have done comparative analysis with the current parameters. METHODS: The average flow is derived by taking the integration from the beginning of the expiration to the end, and divides the integrated value by the number of data counts. Additionally, the acceleration wave is derived by taking the second degree derivative of the flow volume curve. RESULTS: The average flow showed strong correlation among healthy male and healthy female V50, obstructive index and criteria for COPD severity patients. Also, we were able to obtain the maximum acceleration from the acceleration wave. Significantly, this value showed strong correlation with the COPD patient's peak flow and average flow/peak flow. CONCLUSIONS: If the ratio of the average flow and the peak flow is below a fixed criterion, it is an obstructive lung disease, if it is above, it is possible to detect restrictive lung disease. Since the maximum acceleration rate of the acceleration wave is derived by the start of the expiration nearly up to 100 ml, it is especially possible to detect minute changes of the flow speed in large respiratory tract.

CT assessment of subtypes of pulmonary emphysema in females.

We performed a retrospective study examining the prevalence and subtypes of pulmonary emphysema (PE) identified by computed tomography (CT) in females. We reviewed the records of 1,687 female subjects who had undergone CT. They were divided into the following 2 age groups:group A (＜50 years) and group B (≥50 years). PE was diagnosed by the presence of low-attenuation areas using visual assessment (grades 0-3) on CT images. Two subtypes of PE were observed:centrilobular emphysema (CLE) and paraseptal emphysema (PSE). PE was divided into the following 3 categories:I (CLE or CLE-predominant);II (CLE and PSE of equal extent);and III (PSE or PSE-predominant). PE was found in 64 of 274 smokers (23.3%) and 54 of 1,413 non-smokers (3.8%). In smoking subjects, when grades 1 and 2 were grouped together as mild PE, the mean age for CT grade 3 (severe PE) was significantly higher than that for mild PE. In group A, category III predominated, whereas category I was more prevalent in group B, in both smoking and non-smoking subjects. A high incidence of PE was found in smoking subjects as compared with non-smoking subjects. PSE predominated in younger subjects, whereas CLE predominated in older subjects.

A novel method for determining adjacent lung segments with infrared thoracoscopy.

OBJECTIVES: We investigated a new technique for identifying the lung intersegmental line using infrared thoracoscopy with intravenous injection of indocyanine green. METHODS: This was an experimental animal study, and target segments were established preoperatively. Six adult beagle dogs underwent thoracotomy. After the corresponding pulmonary artery of the target segment had been ligated, indocyanine green was administered intravenously during infrared thoracoscopy. The lung was separated into 2 areas, white and blue, according to the blood flow on the monitor. We marked the visceral pleura with electrocautery along the transition zone showing a change in color from blue to white. The experimental lung was removed and subjected to pathologic and radiologic analysis. RESULTS: After injection of indocyanine green, infrared thoracoscopy showed that the area of normal perfusion changed to blue, whereas the area at which perfusion was absent remained white. The transition zone between colors was distinct, and the blue stain remained visible during the marking procedure. Three-dimensional computed tomographic analysis indicated that the marking separated the target segmental bronchus from the adjacent one. Detailed macroscopic and microscopic study confirmed that the marking corresponded to the intersegmental line. CONCLUSION: By using infrared thoracoscopy with indocyanine green, it is possible to detect the intersegmental line without inflating the lung.

Evaluation of subsubsegmental pulmonary arteries of the posterior and anterior segments of the right upper lobe using multidetector row computed tomography with multiplanar reconstruction images.

PURPOSE: We evaluated the patterns of subsubsegmental pulmonary arteries of the right upper lobe (posterior segment: S2; anterior segment: S3) with multiplanar reconstruction (MPR) images by multidetector row computed tomography (MDCT). MATERIALS AND METHODS: A total of 64 patients who had undergone MDCT scans were included in the study. The subsubsegmental arteries were named by adding "i" or "ii" as the superior or the inferior branch, respectively, of the subsegmental arteries. The subsubsegmental arteries of S2 (A2ai, A2aii, A2bi, A2bii) and S3 (A3ai, A3aii, A3bi, A3bii) were evaluated as arising from either the recurrent artery (RA) or the ascending artery (AA). RESULTS: A2ai originated from the RA and AA in 43 and 21 patients, respectively. The corresponding numbers were 32 each for A2aii; 28 and 36 for A2bi; 23 and 41 for A2bii; 60 and 4 for A3ai; 43 and 21 for A3aii; 59 and 5 for A3bi; and 54 and 10 for A3bii. CONCLUSION: The branching pattern of the subsubsegmental pulmonary arteries in the right upper lobe (S2 and S3) could be visualized using MDCT with MPR images.

[18F]fluorodeoxyglucose positron emission tomography imaging in a case of relapsing polychondritis.

Relapsing polychondritis is a rare multisystemic disease that is characterized by recurrent inflammation of the cartilaginous structures of the external ear, nose, joint, larynx, and tracheobronchial tree. Airway involvement is present in up to 50% of patients with the disease and is a major cause of morbidity and mortality. We describe a patient with relapsing polychondritis presenting with tracheal and bronchial abnormalities that were identified by an increased uptake on [18F]fluorodeoxyglucose positron emission tomography.

Diagnostic value of kinetic analysis using dynamic FDG PET in immunocompetent patients with primary CNS lymphoma.

PURPOSE: The purpose of this study was to investigate the accumulation of FDG in immunocompetent patients with primary central nervous system (CNS) lymphoma using qualitative and quantitative PET images and to compare baseline with follow-up PET after therapy. METHODS: Twelve immunocompetent patients with CNS lymphoma were examined. Dynamic emission data were acquired for 60 min immediately following injection of FDG. In seven patients, repeated PET studies were performed after treatment. Applying a three-compartment five-parameter model, K (1), k (2), k (3), k (4), vascular fraction (V ( B )) and cerebral metabolic rate of glucose (CMR(Glc)) were obtained. We evaluated the FDG uptake visually using qualitative and parametric images and quantitatively using parametric images. RESULTS: A total of 12 lesions were identified in ten patients with newly diagnosed CNS lymphoma. On visual analysis, ten lesions showed an increase on qualitative images, eight showed an increase on K (1) images, 12 showed an increase on k (3) images and ten showed an increase on CMR(Glc) images. On quantitative analysis, k (2), k (3) and CMR(Glc) values of the lesion were significantly different from those of the normal grey matter (p<0.02-0.0005). A total of three lesions were identified in two patients with recurrent tumour. All three lesions showed an increase on qualitative, k (3) and CMR(Glc) images. The K (1), k (2), k (3) and CMR(Glc) values after treatment were significantly different from those obtained before treatment (p<0.04-0.008). CONCLUSION: Kinetic analysis, especially with respect to k (3), using dynamic FDG PET might be helpful for diagnosis of CNS lymphoma and for monitoring therapeutic assessment.

Usefulness of 99mTc-Technegas and 133Xe dynamic SPECT in ventilatory impairment.

AIM: To assess the usefulness of SPECT images using (99m)Tc-Technegas (Technegas) and (133)Xe dynamic single photon emission computed tomography (SPECT) (Xe gas) and high-resolution computed tomography (HRCT), as compared with pathological assessment in the detection of small-airway disease including pulmonary emphysema. METHODS: Seventeen patients with lung cancer were studied. All patients who had undergone both Technegas and Xe gas and CT prior to surgery were examined. SPECT and HRCT results were compared with the results of pathological findings. Histopathological analysis was performed in an area distant from cancer in lobectomy specimens obtained at surgery. Pathological analysis was performed in relation to bronchitis, bronchiolitis, fibrosis of the alveoli and disruption in walls of the alveoli. RESULTS: Pathological abnormality (mild-to-moderate abnormal change) was seen in all 17 cases. Three patients showed low attenuation areas on CT, and abnormal patterns in SPECT images. In 11 of 14 patients who showed normal findings on CT, SPECT imaging depicted abnormal findings. The remaining three patients had no abnormal findings on CT and both SPECT imaging. CONCLUSION: Technegas and (133)Xe SPECT imaging is useful for evaluating small-airway disease including pulmonary emphysema. Furthermore, SPECT imaging is more useful than morphological HRCT imaging in the evaluation of small-airway disease including pulmonary emphysema.

Comparative evaluation of 18F-FDG PET and 67Ga scintigraphy in patients with sarcoidosis.

UNLABELLED: 67Ga scintigraphy has been used for years in sarcoidosis for diagnosis and the extent of the disease. However, little information is available on the comparison of 18F-FDG PET and 67Ga scintigraphy in the assessment of sarcoidosis. The purpose of this study was to compare the uptake of 18F-FDG and 67Ga in the evaluation of pulmonary and extrapulmonary involvement in patients with sarcoidosis. METHODS: Eighteen patients with sarcoidosis were examined. 18F-FDG PET was performed at 1 h after injection of 185-200 MBq 18F-FDG. 67Ga whole-body planar and thoracic SPECT images were acquired 72 h after injection of 111 MBq 67Ga. We evaluated 18F-FDG and 67Ga uptake visually and semiquantitatively using standardized uptake values (SUVs) and the ratio of lesion to normal lumbar spine (L/N ratio), respectively. The presence of pulmonary and extrapulmonary lesions was evaluated histopathologically or by the radiologic findings. RESULTS: Five patients had only pulmonary lesions, 12 patients had both pulmonary and extrapulmonary lesions, and 1 patient had only an extrapulmonary lesion. Both 67Ga planar and SPECT images detected 17 of 21 (81%) clinically observed pulmonary sites. The mean +/- SD of the L/N ratio was 1.97 +/- 1.09. 67Ga planar images detected 15 of 31 (48%) clinically observed extrapulmonary sites. The mean +/- SD of the L/N ratio was 1.17 +/- 0.33. 18F-FDG PET detected all 21 (100%) clinically observed pulmonary sites. The mean +/- SD of the SUV was 7.40 +/- 2.48. 18F-FDG PET detected 28 of 31 (90%) clinically observed extrapulmonary sites. The mean +/- SD of the SUV was 5.90 +/- 2.75. CONCLUSION: The results of this clinical study suggest that 18F-FDG PET can detect pulmonary lesions to a similar degree as 67Ga scintigraphy. However, 18F-FDG PET appears to be more accurate and contributes to a better evaluation of extrapulmonary involvement in sarcoidosis patients.

Bifid intrathoracic rib: a case report and classification of intrathoracic ribs.

Bifid intrathoracic rib is a very rare anomaly of the ribs that is characterized by an osseous prominence of a rib into the thoracic cavity. We report a 21-year-old woman with bifid intrathoracic rib arising from the anterior-lateral portion of a depressed 4th rib, based on findings from chest radiography and computed tomography (CT). This is only the second reported case of this type of intrathoracic rib worldwide. We discuss differential diagnoses for this case and suggest a classification of intrathoracic rib from the perspective of morphology and developmental biology.

A case of non-hodgkin's lymphoma of the ovary: usefulness of 18F-FDG PET for staging and assessment of the therapeutic response.

Primary ovarian lymphoma as the initial manifestation is rare. A 27-year-old woman presented to our hospital with the symptoms of lower abdominal fullness and pollakisuria. CT scan and MRI revealed bilateral ovarian tumors, which showed heterogeneous masses. 18F-FDG PET revealed strong uptake by the abdominal masses, and the maximum standardized uptake value (SUVmax) was 12.5. Abnormal uptake was not shown by other regions. An exploratory laparotomy was performed. Histological findings revealed diffuse large B-cell lymphoma. The clinical stage was IV according to the Ann Arbor system. International prognostic index (IPI) was 3 (high-intermediate risk). Chemotherapy was administered consisting of three courses of an R-CHOP regimen, and 18F-FDG PET and CT scan revealed no signs of involvement 3 months after initiation of the chemotherapy. 18F-FDG PET was a useful method for staging and assessment of the therapeutic response in primary ovarian lymphoma.

Dual-time-point 18F-FDG PET for the evaluation of gallbladder carcinoma.

UNLABELLED: Conventional imaging techniques such as ultrasonography, CT, and MRI are able to detect gallbladder abnormalities but are not always able to differentiate a malignancy from other disease processes such as cholecystitis. The purpose of the present study was to evaluate the efficacy of dual-time-point (18)F-FDG PET for differentiating malignant from benign gallbladder disease. METHODS: The study evaluated 32 patients who were suspected of having gallbladder tumors. (18)F-FDG PET (whole body) was performed at 62 +/- 8 min (early) after (18)F-FDG injection and was repeated 146 +/- 14 min (delayed) after injection only in the abdominal region. We evaluated the (18)F-FDG uptake both visually and semiquantitatively. Semiquantitative analysis using the standardized uptake value (SUV) was performed for both early and delayed images (SUV(early) and SUV(delayed), respectively). The retention index (RI) was calculated according to the equation (SUV(delayed) - SUV(early)) x 100/SUV(early). The tumor-to-liver ratio was also calculated. RESULTS: The final diagnosis was gallbladder carcinoma in 23 patients and benign disease in 9 patients. For visual analysis of gallbladder carcinoma, delayed (18)F-FDG PET images improved the specificity of diagnosis in 2 patients. When an SUV(early) of 4.5, SUV(delayed) of 2.9, and RI of -8 were chosen as arbitrary cutoffs for differentiating between malignant and benign conditions, sensitivity increased from 82.6% to 95.7% and 100% for delayed imaging and combined early and delayed imaging (i.e., RI), respectively. With the same criteria, specificity decreased from 55.6% to 44.4% for delayed imaging and combined early and delayed imaging, respectively. The specificity of (18)F-FDG PET improved to 80% in the group with a normal level of C-reactive protein (CRP) and decreased to 0% in the group with an elevated CRP level. For gallbladder carcinoma, both SUV and tumor-to-liver ratios derived from delayed images were significantly higher than the ratios derived from early images (P < 0.0001). CONCLUSION: Delayed (18)F-FDG PET is more helpful than early (18)F-FDG PET for evaluating malignant lesions because of increased lesion uptake and increased lesion-to-background contrast. However, the diagnostic performance of (18)F-FDG PET depends on CRP levels.

CT for acute stage of closed head injury.

Brain damage after head injury can be classified by its time course. Primary damage that includes acute subdural hematoma (SDH), acute epidural hematoma (EDH), and intraaxial lesions that include contusions, diffuse axonal injury (DAI), and intracranial hemorrhage (ICH), occurs at the moment of impact and is thought to be irreversible. Secondary damage that includes herniations, diffuse cerebral swelling, and secondary infarction and hemorrhage, evolves hours or days after injury as a consequence of systemic or intracranial complications. The duration and severity of secondary damage influence outcome. Head injury management is focused on preventing, detecting, and correcting such secondary damage. CT has been widely used for the neuromonitoring of head trauma. CT is the gold standard for the detection of intracranial abnormalities and is a safe method for survey. While MRI is more sensitive and accurate in diagnosing cerebral pathology, CT is considered the most critical imaging technique for the management of closed head-injured patients in the acute stage. In this article, we review the imaging findings and literature of various lesions of closed head injury in the acute stage.

Contribution of whole body FDG-PET to the detection of distant metastasis in pancreatic cancer.

OBJECTIVE: Accurate baseline staging is necessary to appropriately treat pancreatic cancer. The present study was undertaken to evaluate the clinical contribution of whole body FDG-PET to the detection of distant metastasis in pancreatic cancer. METHODS: A total of consecutive 42 patients with previously untreated pancreatic cancer were examined. Whole body FDG-PET imaging for initial staging was performed with a 3D acquisition and iterative reconstruction on Siemens ECAT HR+ scanner at 1 hour post 185-200 MBq 18F-FDG injection. PET findings were correlated with clinical and radiological data to determine the impact of PET on staging. RESULTS: In 16 patients, there were one or more sites of metastasis based on clinical data. FDG-PET correctly identified the presence of metastasis in 13 of 16 patients and its absence in 23 of the remaining 26 patients. Thus, FDG-PET missed 4 metastatic sites in 4 patients (liver and lung metastasis). FDG-PET correctly identified 8 metastatic sites in 7 patients (peritoneal dissemination and liver, bone and supraclavicular lymph node metastasis), which were missed on CT imaging. Based on whole body FDG-PET, the clinical stage was changed in 5 of 42 patients (11.9%). CONCLUSIONS: These results suggest that FDG-PET and CT appear to have a complementary role in the detection of distant metastasis in patients with pancreatic cancer.

Effect of gravitation for detection of bronchioloalveolar carcinoma on computed tomography.

A 64-year-old female was found to have localized ground-glass opacity (GGO) in the middle lobe on a chest computed tomography (CT) for screening. Middle lobectomy with video-assisted thoracoscopic surgery (VATS) was undertaken, and pathological diagnosis was a bronchioloalveolar carcinoma (BAC) in stage IA. A follow-up CT a year following the surgery revealed localized GGO in area S6 of the left lung. However, it disappeared during the gravitation-dependent gradient in the observation period. The patient was scanned again under prone position to exclude the gravitational effect, resulting in definite detection of the GGO. Left extended S6 segmentectomy with VATS was performed, and pathological diagnosis was a BAC in stage IA. As GGO existing in a gravitation-dependent area may be masked by the gravitation-dependent density, a change of the scanning position may lead to a proper detection of the tumor for the diagnosis of BAC.

Multiple rheumatoid nodules with rapid thin-walled cavity formation producing pneumothorax.

We report a rare case of multiple rheumatoid nodules that on chest CT demonstrated peripheral location with thin-walled cavity formation, rapid increase in size within several months, and complicating pneumothorax, pneumomediastinum, and subcutaneous emphysema due to bronchopleural fistula formation.