Managing the Small Pulmonary Nodule Discovered by CT

OBJECTIVES

To review the Early Lung Cancer Action Project experience and the medical literature from 1993 to 2003 on detection of the small, noncalcified pulmonary nodule by CT in order to formulate a management algorithm for these nodules.

DESIGN

Prospective noncomparative study of smokers without prior malignancy and a review of the medical literature of CT screening of lung cancer.

INTERVENTIONS

Chest CT and, where appropriate, CT observation for nodule growth, antibiotics, CT-guided fine-needle aspiration (FNA) biopsy, fiberoptic bronchoscopy, and video-assisted thoracoscopic surgery (VATS).

RESULTS

The following factors influence the probability of malignancy in a CT-detected, small, noncalcified pulmonary nodule: size, change in size, age, smoking history, density, number of nodules, gender, circumstance of the CT, spirometry, occupational history, and endemic granulomatous disease. The two diagnostic techniques most useful in evaluating the CT-detected, small, noncalcified nodule are short-term observation of nodule growth by CT and CT-guided FNA. Due to small nodule size and the frequent finding of nonsolid or part-solid nodules, positron emission tomography, fiberoptic bronchoscopy, and VATS were less useful.

CONCLUSIONS

Pulmonologists are frequently asked to evaluate the CT-detected, small, noncalcified nodule invisible on standard chest radiography. Immediate biopsy is justified if the likelihood of cancer is high, but if that likelihood is low or intermediate, a period of observation by CT is appropriate. VATS or thoracotomy are rarely necessary for a diagnosis of lung cancer in the CT-detected small pulmonary nodule.

Aspiration cytology of elastofibroma dorsi: case report with ultrastructural and immunohistochemical findings

Elastofibroma is a well-recognized tumor-like process which typically occurs in the soft tissue of the shoulder. Although fine-needle aspiration (FNA) represents a quick and simple method for definitive diagnosis, the possibility of a false-negative diagnosis is high due to the hypocellularity of the smears. However, a high index of suspicion based on the clinical presentation of a firm mass in a typical location in an elderly person, usually female, aids in the diagnosis. We describe the FNA findings of elastofibroma dorsi in an 89-yr-old woman which, although hypocellular, contained diagnostic aggregates of petaloid globules within a collagenous matrix. The cytologic material showed a green-yellow autofluorescence of the altered elastic fibers with ultraviolet light. Transmission electron microscopy revealed an elongated beaded appearance with small electron densities and obliteration of the central elastin core. The presence of a hypocellular aspirate with autofluorescent elastic fibers should suggest the possibility of elastofibroma dorsi.

Two-dimensional multi-criterion segmentation of pulmonary nodules on helical CT images

A multi-criterion algorithm for automatic delineation of small pulmonary nodules on helical CT images has been developed. In a slice-by-slice manner, the algorithm uses density, gradient strength, and a shape constraint of the nodule to automatically control segmentation process. The multiple criteria applied to separation of the nodule from its surrounding structures in lung are based on the fact that typical small pulmonary nodules on CT images have high densities, show a distinct difference in density at the boundary, and tend to be compact in shape. Prior to the segmentation, a region-of-interest containing the nodule is manually selected on the CT images. Then the segmentation process begins with a high density threshold that is decreased stepwise, resulting in expansion of the area of nodule candidates. This progressive region growing approach is terminated when subsequent thresholds provide either a diminished gradient strength of the nodule contour or significant changes of nodule shape from the compact form. The shape criterion added to the algorithm can effectively prevent the high density surrounding structures (e.g., blood vessels) from being falsely segmented as nodule, which occurs frequently when only the gradient strength criterion is applied. This has been demonstrated by examples given in the Results section. The algorithm's accuracy has been compared with that of radiologist's manual segmentation, and no statistically significant difference has been found between the nodule areas delineated by radiologist and those obtained by the multi-criterion algorithm. The improved nodule boundary allows for more accurate assessment of nodule size and hence nodule growth over a short time period, and for better characterization of nodule edges. This information is useful in determining malignancy status of a nodule at an early stage and thus provides significant guidance for further clinical management.

Massive hiatal hernias: the anatomic basis of repair

OBJECTIVES

In the repair of giant hiatal hernias, controversy persists as to whether an antireflux repair is required and whether a Collis gastroplasty is necessary. This study was undertaken to determine the location of the gastroesophageal junction in giant hiatal hernias with an intrathoracic stomach, as well as the outcome after repair without a Collis gastroplasty.

METHODS

Fifty-two patients were evaluated for a giant hiatal hernia, of whom 47 underwent surgical correction. Preoperative evaluation included esophagoscopy (n = 45), gastrointestinal series (n = 40), esophageal manometry (n = 20), and 24-hour pH testing (n = 13). The dominant clinical features were acute chest or abdominal pain (72%), heartburn (53%), and gastrointestinal bleeding (49%). The gastroesophageal junction was located in the mediastinum in 77% of patients, in the abdomen in 17%, and was not determined in 6%. Twenty-eight patients (59%) had clinical or objective evidence of reflux. Reduction with an antireflux repair without a gastroplasty was done in 47 (Belsey, n = 28; Nissen, n = 19). An excellent or good result was achieved in 38 patients (90%) with a median follow-up of 45 months.

CONCLUSIONS

These results, obtained without a Collis gastroplasty, are equivalent to those obtained by an antireflux repair with an esophageal lengthening procedure. The frequent location of the gastroesophageal junction in the mediastinum suggests that these massive hernias often are the result of progressive enlargement of a sliding component. An antireflux repair is therefore necessary in the majority of patients.

Torsion of the upper lobe in pneumothorax

A rounded density is occasionally seen hanging down from the hilus in the presence of a large pneumothorax. To find an explanation for this appearance, the authors obtained a right-sided bronchogram on a baboon, after which they induced pneumothorax on the same side. This experiment demonstrated that the rounded density is formed by a twisted and atelectatic upper lobe.

Right phrenic nerve: anatomy, CT appearance, and differentiation from the pulmonary ligament

The pulmonary ligament appears on computed tomographic (CT) sections as a thin, high-attenuation line, frequently seen above or at the level of the diaphragm and usually extending from the region of the esophagus. However, another line coursing laterally from the midportion of the inferior vena cava has also been identified as the pulmonary ligament. The authors examined sections from eight cadavers and 80 chest CT examinations to more clearly delineate the pulmonary ligament from this second structure. Anatomic and CT correlation proves that the line seen at the midportion of the inferior vena cava represents the right phrenic nerve and that the right pulmonary ligament is located posterior to it.