Carcinomatous solitary pulmonary nodules: evaluation of the tumor-bronchi relationship with thin-section CT

Risk assessment of malignancy in solitary pulmonary nodules in lung computed tomography: a multivariable predictive model study

Background:

Computed tomography images are easy to misjudge because of their complexity, especially images of solitary pulmonary nodules, of which diagnosis as benign or malignant is extremely important in lung cancer treatment. Therefore, there is an urgent need for a more effective strategy in lung cancer diagnosis. In our study, we aimed to externally validate and revise the Mayo model, and a new model was established.

Methods:

A total of 1450 patients from three centers with solitary pulmonary nodules who underwent surgery were included in the study and were divided into training, internal validation, and external validation sets (n = 849, 365, and 236, respectively). External verification and recalibration of the Mayo model and establishment of new logistic regression model were performed on the training set. Overall performance of each model was evaluated using area under receiver operating characteristic curve (AUC). Finally, the model validation was completed on the validation data set.

Results:

The AUC of the Mayo model on the training set was 0.653 (95% confidence interval [CI]: 0.613–0.694). After re-estimation of the coefficients of all covariates included in the original Mayo model, the revised Mayo model achieved an AUC of 0.671 (95% CI: 0.635–0.706). We then developed a new model that achieved a higher AUC of 0.891 (95% CI: 0.865–0.917). It had an AUC of 0.888 (95% CI: 0.842–0.934) on the internal validation set, which was significantly higher than that of the revised Mayo model (AUC: 0.577, 95% CI: 0.509–0.646) and the Mayo model (AUC: 0.609, 95% CI, 0.544–0.675) (P < 0.001). The AUC of the new model was 0.876 (95% CI: 0.831–0.920) on the external verification set, which was higher than the corresponding value of the Mayo model (AUC: 0.705, 95% CI: 0.639–0.772) and revised Mayo model (AUC: 0.706, 95% CI: 0.640–0.772) (P < 0.001). Then the prediction model was presented as a nomogram, which is easier to generalize.

Conclusions:

After external verification and recalibration of the Mayo model, the results show that they are not suitable for the prediction of malignant pulmonary nodules in the Chinese population. Therefore, a new model was established by a backward stepwise process. The new model was constructed to rapidly discriminate benign from malignant pulmonary nodules, which could achieve accurate diagnosis of potential patients with lung cancer.

Diagnostic Yield of the Virtual Bronchoscopic Navigation System Guided Sampling of Peripheral Lung Lesions using Ultrathin Bronchoscope and Protected Bronchial Brush

OBJECTIVES

The use of an ultrathin bronchoscope (UB) to diagnose peripheral pulmonary lesions is described. A virtual bronchoscopic navigation system was used to direct the ultrathin scope to the nodule. One of the constraints of this technique was the inability to confirm the target lesion position during biopsy by using a conventional linear endobronchial ultrasound probe, since the probe does not fit into a 1.2 mm working channel of this bronchoscope. The aim of the study was to review our institutional experience with the use of a UB for sampling peripheral pulmonary lesions using the transbronchial brush guided by virtual bronchoscopy. We describe a technique wherein we attempt to brush all the visible bronchial sub-segments once the bronchoscope has reached close to the nodule.

MATERIALS AND METHODS

In total, 52 patients underwent the procedure between 2010 and 2017. A multiplanar computed tomography (CT) scan of the chest was obtained and subsequently uploaded to the Lung Point Virtual bronchoscopy navigation software. The UB was parked close to the lesion. All visible airway branches were then brushed using a protected bronchial brush. The data were retrospectively abstracted from the electronic medical records using standardized forms.

RESULTS

A total of 52 lesions (40 solid, 8 part-solid, 3 cavitary, and 1 ground-glass) were sampled using a transbronchial brush (median, 2; range, 1-8). Twenty-four lesions were under 2 cm in size. The overall success rates were 67.3%. The average diameter of nodules was 2.7±1.01 cm; 65% lesions were in the outer-third of the lungs. The cancer-specific sensitivity was 72.5%. The presence of bronchus sign; location of the lesion; and the characteristics, size, and stage of cancer did not have any impact on the diagnostic yield.

CONCLUSION

Virtual bronchoscopy-guided ultrathin bronchoscopy with bronchial brushing is safe and has a diagnostic yield comparable to other described techniques for evaluating peripheral pulmonary nodules.

The value of the air bronchogram sign on CT image in the identification of different solitary pulmonary consolidation lesions

The aim of the present study is to investigate the value of air bronchogram sign on computed tomography (CT) image in the differential diagnosis of solitary pulmonary consolidation lesions (SPLs).A total of 105 patients (including 39 cases of lung cancer, 43 cases of tuberculosis, and 23 cases of pneumonia) with SPLs were evaluated for the CT features of air bronchogram sign in this retrospective study. The shape and lumen of the bronchi with air bronchogram sign, the length of the involved bronchus with air bronchogram sign, the length of lesion on the same plane and direction, and the ratio between the length of the involved bronchus and that of the lesion were evaluated.In total, there were 172 segmental and subsegmental bronchi involved. There were 62 segmental and subsegmental bronchi involved among 39 lung cancer cases, 77 segmental and subsegmental bronchi involved among 43 tuberculosis cases, and 33 segmental and subsegmental bronchi involved among 23 pneumonia cases. The shape of the bronchi with air bronchogram sign was significantly different among lung cancer, tuberculosis, and pneumonia (P < .05). The lumen of the bronchi with air bronchogram sign was also significantly different among the 3 SPLs (P < .05). The length of the involved bronchus with air bronchogram sign and the ratio between the length of the involved bronchus and that of the lesion were significantly different between lung cancer and tuberculosis (P < .05), or between lung cancer and pneumonia (P < .05), but not between tuberculosis and pneumonia (P > .05). No significant difference was found in the length of lesion among the 3 SPLs (P > .05).The shape and lumen of the bronchi with air bronchogram sign can be used to distinguish lung cancer, tuberculosis, and pneumonia. The length of the involved bronchus with air bronchogram sign and the ratio between the length of the involved bronchus and that of the lesion can be used to distinguish lung cancer from tuberculosis and pneumonia.

[Combined use of thin-section CT and 18F-FDG PET/CT for characterization of solitary pulmonary nodules]

OBJECTIVE

To investigate whether fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) combined with thin-section CT improves the diagnostic performance for solitary pulmonary nodules (SPNs).

METHODS

A total of 267 patients underwent examinations with 18F-FDG PET/CT and thin-section CT for evaluating the SPNs with undetermined nature, which was further confirmed by pathological examination or clinical follow-up. The performance of two diagnostic criteria based on findings in PET/CT alone (Criterion 1) and in PET/CT combined with thin-section CT (Criterion 2) were compared.

RESULTS

Thin-section CT provided greater diagnostic information for SPNs in 84.2% of the patients. Compared with Criterion 1, the diagnosis based on Criterion 2 significantly increased the diagnostic sensitivity (80.4% vs 91%, P&lt;0.01) and accuracy (76.4% vs 87.2%, P<0.01) for lung cancer. The lesion size and the CT features including lobulation, air bronchogram, and feeding vessel, but not SUV_max, were all helpful for characterizing non-solid SPNs. Thin-section CT rectified diagnostic errors in 50% (20/40) of the cancerous lesions, which had been diagnosed as benign by PET due to their low metabolism. For non-solid SPNs, Criterion 2 showed a significantly higher diagnostic sensitivity than Criterion 1 (90.0% vs 40.0%, P=0.000) but their diagnostic specificity were comparable (75.2% vs 58.3%, P=0.667). For solid nodules, the use of thin-section CT resulted in no significant improvement in the diagnostic performance (P>0.05).

CONCLUSION

The combination of PET/CT and thin-section CT creates a synergistic effect for the characterization of SPNs, especially non-solid nodules.

Diagnostic performance of convex probe EBUS-TBNA in patients with mediastinal and coexistent endobronchial or peripheral lesions

To compare the performance of convex probe endobronchial ultrasound guided transbronchial needle aspiration (EBUS-TBNA) with conventional endobronchial biopsy (EBB) or transbronchial lung biopsy (TBLB) in patients with mediastinal, and coexisting endobronchial or peripheral lesions.Retrospective review of records of patients undergoing diagnostic EBUS-TBNA and conventional bronchoscopy in 2014.A total of 74 patients had mediastinal, and coexisting endobronchial or peripheral lesions. The detection rate of EBUS-TBNA for mediastinal lesion >1 cm in short axis, EBB for visible exophytic type of endobronchial lesion, and TBLB for peripheral lesion with bronchus sign were 71%, 75%, and 86%, respectively. In contrast, the detection rate of EBUS-TBNA for mediastinal lesion ≤1 cm in short axis, EBB for mucosal hyperemia type of endobronchial lesion, and TBLB for peripheral lesion without bronchus sign were 25%, 63%, and 38%, and improved to 63%, 88%, and 62% respectively by adding EBB or TBLB to EBUS-TBNA, and EBUS-TBNA to EBB or TBLB. Postprocedure bleeding was significantly more common in patients undergoing EBB and TBLB 8 (40%) versus convex probe EBUS-TBNA 2 patients (2.7%, P = 0.0004).EBUS-TBNA is a safer single diagnostic technique compared with EBB or TBLB in patients with mediastinal lesion of >1 cm in size, and coexisting exophytic type of endobronchial lesion, or peripheral lesion with bronchus sign. However, it requires combining with EBB or TBLB and vice versa to optimize yield when mediastinal lesion is ≤1 cm in size, and coexisting endobronchial and peripheral lesions lack exophytic nature, and bronchus sign, respectively.

Using air bronchograms on multi-detector CT to predict the invasiveness of small lung adenocarcinoma

PURPOSE

To investigate the prevalence of multidetector CT (MDCT) air bronchograms and their value in predicting the invasiveness of lung adenocarcinomas.

METHODS

MDCT scans of 606 nodules in 582 patients with a lung adenocarcinoma less than 2cm in diameter confirmed by surgery and pathology were reviewed. Air bronchograms were classified into three patterns: type I, bronchus with intact lumen; type II, bronchus with dilated or tortuous lumen; and type III, bronchus with obstructed lumen.

RESULTS

Air bronchograms were demonstrated on MDCT in 210 of 606 (34.7%) lung adenocarcinomas with 16.6% (35/211) preinvasive lesions (PL), 30.5% (50/164) minimally invasive adenocarcinoma (MIA), and 54.1% (125/231) invasive adenocarcinoma (IAC) (P=0.000); 18.3% (44/240) pure ground-glass nodules (GGNs), 44.2% (137/310) mixed GGNs, and 51.8% (29/56) solid nodules (P=0.000). Type I was slightly more common in MIA (36/164, 22.0%) than IAC (40/231, 17.3%) and PL (30/211, 14.2%) but without differences among them (P=0.147). Type II (PL: 5/211, 2.4%; MIA: 13/164, 7.9%; IAC: 53/231, 22.9%) and type III (PL: 0/211; MIA: 1/164, 0.6%; IAC: 32/231, 13.9%) were observed more frequently with increasing lung adenocarcinoma invasiveness (both P=0.000).

CONCLUSIONS

The prevalence and patterns of air bronchograms on MDCT can predict the invasiveness of small lung adenocarcinomas.

Cost-effectiveness analysis of transbronchial needle aspiration of pulmonary lesions without endobronchial affectation

Transbronchial needle aspiration (TBNA) of pulmonary lesions without endobronchial affectation in combination with transbronchial biopsy (TBB) has been shown to increase diagnostic performance. The objective of this present study was to analyze whether the combination of TBNA with conventional TBB is a cost-effective approach.

METHODOLOGY

Ours is a prospective study that included patients with lung nodules or masses with no evidence of endobronchial lesions after flexible bronchoscopy in whom both TBNA and TBB were performed. We analyzed the additional diagnostic value, the impact of TBNA on the cost of the diagnosis and the minimum level of sensitivity required in order for TBNA combined with TBB to be considered a cost-effective diagnostic approach.

RESULTS

Thirty-six patients were included in the study, 25 of whom were males. TBB reached a histologic diagnosis in 39% of the cases, and its combination with TBNA diagnosed 47%. The mean diameter of the lesions was significantly greater in the positive TBNA cases compared with the negative cases (31 vs. 23mm; p=0,034). The cost analysis did not show the additional TBNA to be more cost-effective, despite demonstrating greater diagnostic sensitivity. The minimum sensitivity required for TBNA combined with TBB to be considered a cost-effective approach was 88%.

CONCLUSION

The contribution of TBNA to TBB in the diagnosis of lung nodules or masses without associated endobronchial lesions does not seem to justify the additional economic cost.

Echoic features as predictors of diagnostic yield of endobronchial ultrasound-guided transbronchial lung biopsy in peripheral pulmonary lesions

The endobronchial ultrasound (EBUS) features of peripheral pulmonary lesions (PPLs) are associated with histopathologic presentation. Certain histologic and radiologic characteristics of peripheral pulmonary lesions affect the diagnostic yield of transbronchial lung biopsies (TBLB). This study aimed to assess the feasibility of EBUS echoic features as predictors of diagnostic yield of TBLB. Four hundred and eight patients with PPLs underwent TBLB. The yields of TBLB in lesions with characteristic EBUS features were compared with those without such features. The overall diagnostic yield of TBLB was 64.2%. Lesion diameter (≥3 cm vs. <3 cm; 69.1% vs. 58.5%, p < 0.05), location of the EBUS probe (within vs. adjacent to lesions; 73.2% vs. 46.3%, p < 0.01) and lesion echogenicity (heterogeneous vs. homogeneous; 76.7% vs. 52.0%, p < 0.01) were associated with higher TBLB yields. In malignant PPLs, the echoic features associated with higher TBLB yields were lesion diameter (≥3 cm vs. <3 cm; 74.4% vs. 62.5%, p < 0.05), location of the EBUS probe (within vs. adjacent to lesions; 78.7% vs. 47.4%, p < 0.01), echoic feature of the margin (noncontinuous vs. continuous; 77.0% vs. 62.4%, p < 0.01) and lesion echogenicity (heterogeneous vs. homogeneous; 77.7% vs. 53.9%, p < 0.01). EBUS probe location, echoic feature of the margin and lesion echogenicity were independent predictors according to the results of multivariate analysis. In conclusion, EBUS features are feasible predictors of diagnostic yield of TBLB in peripheral lung lesions.

Relationship between peripheral lung cancer and the surrounding bronchi, pulmonary arteries, pulmonary veins: a multidetector CT observation

AIM

This study aimed to investigate the relationship between peripheral lung cancer and the surrounding pulmonary vessels and bronchi using contrast-enhanced multidetector computed tomography (MDCT) and to analyze associated factors such as pathology types, stage, size, density, and location of peripheral lung cancer.

MATERIALS AND METHODS

A total of 93 patients with solitary peripheral lung cancers underwent contrast-enhanced MDCT before thoracotomy were enrolled. Multiplanar reconstruction, maximal intensity projection, and volume rendering were used for demonstrating the patterns of the tumor-bronchi (Br), tumor-pulmonary artery (PA) and tumor-pulmonary vein (PV) relationship, respectively. Five subtypes were identified: Type1 (Br1, PA1 and PV1), Br, PA, or PV was erupted at the edge of nodule; Type2 (Br2, PA2, and PV2), erupted at the center of nodule; Type3 (Br3, PA3 and PV3), penetrated through the nodule; Type4, (Br4, PA4 and PV4), contacting the nodule but stretched or encased; Type5 (Br5, PA5, and PV5), contacting the nodule but smoothly compressed.

RESULTS

Both bronchi and PA were interrupted in 70 (Type 1+2); both narrowed in 9 (Type 3+4). The bronchi and PA changes surrounding the lung cancer had positive relations (χ(2)=12.3918, r=0.7524, P<.01). Br1 and PA1 were more often seen in the group of solid, ≥2.0 cm, and Stage II-IV focal lesions, while Br2 and PA2, more often in the group of part-solid, non-solid, <2.0 cm, and Stage I focal lesions. PV2 was more often seen in the part-solid and non-solid focal lesions group, while PV (4+5), more often in solid focal lesions group.

CONCLUSION

MDCT can demonstrate and subtype relationships among peripheral lung cancer and the bronchi, pulmonary arteries and pulmonary veins. This can be the basis for further clinical research and differential diagnosis.

Multivariate study of predictive factors for clearly defined lung lesions without visible endobronchial lesions in transbronchial biopsy

BACKGROUND

Although the diagnostic validity and predictive factors for the diagnostic yield of transbronchial biopsy (TBB) of clearly defined pulmonary lesions with no visible endobronchial lesion have been analyzed in numerous studies, very few have used multivariate analysis techniques to evaluate the validity of TBB as a diagnostic tool or to analyze the independent influence of clearly dependent variables, such as the bronchus sign and lesion size.

METHODS

We retrospectively analyzed all cases in which this type of lesion underwent TBB under fluoroscopic control between 2006 and 2008. The analyzed variables included lesion size, localization, the presence of the bronchus sign, and the final result obtained. We performed a descriptive analysis of the TBB results and a multivariate analysis of the predictive factors for the results using logistic regression techniques.

RESULTS

A total of 273 patients (206 males, 75.5%) were included in the study. The average lesion diameter was 34 (± 16) mm, with 24% 2 cm or smaller. Twenty-eight percent of the lesions were localized in the lower lobes and 32% in the peripheral third of the lung. The bronchus sign was present in 28% of the patients. Seventy-eight percent of the patients had primary or metastatic malignant lung lesions, the rest were benign lesions of diverse etiology. TBB was diagnostic in 45.4% of cases. In the multivariate analysis, the only independent predictors of outcome were malignant etiology (OR = 4.8; 95% CI = 2.210.4), diameter >20 mm (OR = 3.6; 95% CI = 1.8-7.3), and the presence of the bronchus sign (OR = 2.4; 95% CI = 1.3-4.3).

CONCLUSIONS

TBB of lesions clearly delimited without an endobronchial lesion can lead to diagnosis in almost half of the patients. The nature of the lesion, diameter >20 mm, and the presence of the bronchus sign are independent predictors of outcome.

Value of multiplanar reconstruction in MSCT in demonstrating the relationship between solitary pulmonary nodule and bronchus

In this report, we studied the value of the solitary pulmonary nodule (SPN)-bronchus relationship in determining the nature of SPN by multiplanar reconstruction (MPR) in multislice spiral computed tomography (MSCT). One hundred forty-eight SPN cases were enrolled. CT was performed in all cases using MSCT. Images were then transferred to a processing workstation for MPR. The results showed that MPR is a valuable tool for visualizing the SPN-bronchus relationship and that the SPN-bronchus relationship is useful in determining the nature and the degree of differentiation of SPN.

Factors Related to Diagnostic Yield of Transbronchial Biopsy Using Endobronchial Ultrasonography With a Guide Sheath in Small Peripheral Pulmonary Lesions

STUDY OBJECTIVES

To evaluate factors predicting the diagnostic yield of transbronchial biopsy (TBB) using endobronchial ultrasonography with a guide sheath (EBUS-GS) in small peripheral pulmonary lesions (PPLs) </= 30 mm in mean diameter.

DESIGN

Retrospective analysis.

PATIENTS AND METHODS

One hundred fifty-five consecutive patients with 158 small PPLs underwent TBB using EBUS-GS.

RESULTS

A definitive diagnosis was established by TBB using EBUS-GS in 106 PPLs (67%). The diagnostic yield of PPLs </= 15 mm in mean diameter (40%) was significantly lower than that of PPLs > 15 mm and </= 30 mm in mean diameter (76%; p < 0.001). PPLs in which the probe was positioned within the PPL on the endobronchial ultrasonography (EBUS) image had a higher diagnostic yield (83%) than PPLs in which the probe was positioned adjacent to the PPL (61%) or outside the PPL (4%; p < 0.001). There were no significant differences in diagnostic yield for underlying disease, location, CT scan bronchus sign, operator, or type of EBUS probe. In the multivariate analysis, only the position of the probe (within or adjacent to the PPL when judged against outside the PPL) was determined to be a significant factor predicting diagnostic yield. On the other hand, a pathologic diagnosis was established with the first, second, third, fourth, and fifth biopsy specimens in 65%, 80%, 87%, 91%, and 97% of PPLs, respectively.

CONCLUSIONS

The position of the probe (ie, within or adjacent to the PPL) is a significant factor in predicting the diagnostic yield of TBB using EBUS-GS for small PPLs; the optimum number of biopsy specimens is at least five.

Factors Related to Diagnostic Sensitivity Using an Ultrathin Bronchoscope Under CT Guidance

BACKGROUND

We investigated factors related to the diagnostic sensitivity of CT-guided transbronchial biopsy (TBB) using an ultrathin bronchoscope and virtual bronchoscopy (VB) navigation for small peripheral pulmonary lesions.

METHOD

We have performed this procedure on 83 patients with 85 small peripheral pulmonary lesions (< 20 mm in diameter). We analyzed the relationship between the diagnostic sensitivity and the location of the lesions, the bronchial generation to which an ultrathin bronchoscope was inserted, and the lesion-bronchial and lesion-pulmonary arterial relationships on high-resolution CT.

RESULTS

Fifty-six of the 85 lesions (66%) were diagnosed following CT-guided TBB using an ultrathin bronchoscope with VB navigation. The lesions located in the left superior segment of the lower lobe (S6) had a significantly low diagnostic sensitivity compared to other locations (p < 0.01). When an ultrathin bronchoscope could be inserted to the fifth or greater bronchial generation, the yield was above the average diagnostic sensitivity of 66%. Moreover, not only the patients with the presence of a bronchus leading directly to a lesion (CT-bronchus sign), but also the patients with the presence of a pulmonary artery leading to a lesion (CT-artery sign), had high diagnostic sensitivity (p < 0.01). Multivariate analysis revealed that the location of lesion was an independent predictor of diagnostic sensitivity (p < 0.05).

CONCLUSIONS

The location of the lesion, the bronchial generation to which an ultrathin bronchoscope was inserted, and the presence of a bronchus as well as a pulmonary artery leading to the lesion were valuable for predicting successful CT-guided TBB using an ultrathin bronchoscope with VB navigation.

Management of an incidentally discovered pulmonary nodule

The incidental finding of a pulmonary nodule on computed tomography (CT) is becoming an increasingly frequent event. The discovery of such a nodule should evoke the possibility of a small bronchogenic carcinoma, for which excision is indicated without delay. However, invasive diagnostic procedures should be avoided in the case of a benign lesion. The objectives of this review article are: (1) to analyze the CT criteria defining benign nodules, nodules of high suspicion of malignancy and indeterminate nodules, (2) to analyze the diagnostic performances and limitations of complementary investigations requested to characterize indeterminate lung nodules, (3) to review the criteria permitting to assess the probability of malignancy of indeterminate nodules and (4) to report on the new guidelines provided by the Fleischner Society for the management of small indeterminate pulmonary nodules, according to their prior probability of malignancy.

The relationship between solitary pulmonary nodules and bronchi: multi-slice CT-pathological correlation

AIM

To investigate the relationship between solitary pulmonary nodules (SPN) and bronchi and its value in predicting the nature of the SPN.

MATERIALS AND METHODS

We performed volumetric targeted scans of 0.5 mm collimation with multi-slice computed tomography (MSCT), reconstructing multiplanar reconstructions (MPR), curved multiplanar reconstructions (CMPR) and surface-shaded display (SSD) images of bronchi in 78 consecutive patients with SPN (53 malignant and 25 benign) and correlated the findings with those of macroscopic and microscopic specimens.

RESULTS

With this CT protocol, the third to seventh-order bronchi were shown continuously and very clearly in all patients. CT findings were consistent with those of specimens. CT demonstrated the relationship between the SPN and bronchi in 46 (86.8%) malignant and 18 (75.0%) benign nodules. Five types of tumour-bronchus relationships were identified with MSCT. Type I: the bronchus was obstructed abruptly by the SPN; type II: the bronchus penetrated into the SPN with tapered narrowing and interruption; type III: the bronchial lumen shown within the SPN was patent and intact; type IV: the bronchus ran around the periphery of the SPN with intact lumen; type V: the bronchus was displaced, compressed and narrowed by the SPN. Malignant nodules were most commonly of type I (58.5%), secondly of type IV (26.4%) and rarely of type V (1.9%). Benign nodules were most often of type V (36.0%), followed by type III (20.0%), type I (16.0%), and there were no type II. Types I, II and IV were more common in malignant nodules, whereas type V was seen more frequently seen in benign nodules (p<0.05). There was no statistically significant difference between the two groups regarding type III.

CONCLUSION

Ultra-thin section with MSCT and MPR, CMPR and SSD reconstruction can improve the demonstration of the patterns of tumour-bronchus relationships, which can reflect the pathological changes of the nodules to some extent and help differentiate malignant from benign tumours.

Solitary pulmonary nodules: potential role of dynamic MR imaging in management initial experience

PURPOSE

To evaluate the utility of dynamic magnetic resonance (MR) imaging in the management of solitary pulmonary nodules (SPNs).

MATERIALS AND METHODS

Fifty-eight patients with 58 pathologic analysis-proved SPNs (diameter < 30 mm) underwent dynamic 1.5-T MR imaging. The 58 SPNs were classified into three groups at pathologic analysis: malignant SPNs (n = 38), active infections (n = 10), or benign SPNs (n = 10). From signal intensity-time curves generated after the bolus injection of contrast material, the maximum relative enhancement ratio and slope of enhancement were calculated and statistically compared among the three groups. Threshold values of these two dynamic MR indexes were determined on the basis of positive differentiations.

RESULTS

The mean relative enhancement ratio and mean slope of enhancement for the malignant SPN group were significantly higher than those for the benign SPN group and significantly lower than those for the active infection group (P <.05). With 0.15 as the threshold maximum relative enhancement ratio for distinguishing the malignant SPN and active infection groups from the benign SPN group, the sensitivity, specificity, and accuracy were 100%, 70%, and 95%, respectively. With 0.025/sec as the threshold slope of enhancement, all SPNs with malignancy and active infection were clearly distinguished from benign SPNs.

CONCLUSION

Dynamic MR indexes were useful in the differentiation between SPNs that necessitated further evaluation or treatment (malignancy and active infection) and SPNs that did not necessitate further evaluation or treatment (benign nodules).

Bronchoscopy and needle biopsy techniques for diagnosis and staging of lung cancer

Lung cancer is the leading cause of cancer deaths in the United States. The individual therapeutic approach and prognosis depends on accurate diagnosis and staging. Flexible bronchoscopy (FB) and transthoracic needle biopsy (TNB) are the most widely used techniques for this purpose. This article provides a critical overview of indications, diagnostic yield, and limitations of bronchoscopy and TNB in the diagnosis of lung cancer.

An evaluation of computed tomography as an aid to diagnosis in patients undergoing bronchoscopy for suspected bronchial carcinoma

AIM

To determine whether computed tomography (CT) can predict the likelihood of obtaining a positive tissue diagnosis at fibreoptic bronchoscopy (FOB), or demonstrate an alternative means of achieving a tissue diagnosis, in patients presenting with a high clinical suspicion of primary bronchogenic carcinoma and an abnormal chest radiograph (CXR).

MATERIALS AND METHODS

Sixty-two patients presenting with a high clinical suspicion of carcinoma and an abnormal CXR had chest and liver CT and FOB performed. All patients subsequently had histocytological confirmation of malignancy. Features recorded from the CTs included: the site and characteristics of a mass if present, and its relationship to adjacent airways; the presence of presumed metastatic disease; and a CT prediction of the likelihood of positive FOB was made.

RESULTS

Of the patients, 41/62 (66%) had inoperable stage IIIb/IV disease. Fibreoptic biopsy yielded positive tissue diagnoses in 38/62 (61%). Computed tomography features predicting a positive FOB in this group included: ill-definition of the mass (12/15, 80%); a mass <4 cm from the origin of the nearest lobar bronchus (36/53, 68%); an endobronchial component of mass (22/24, 92%); a segmental or larger airway leading to the mass (30/35, 86%). Overall, CT had positive and negative predictive values for positive FOB of 85% and 78% respectively. The accuracy of the overall CT prediction of positive FOB was better than the accuracy of any of the individual factors. Seventeen of 62 (27%) patients had presumed metastatic disease suitable for percutaneous biopsy.

CONCLUSION

Computed tomography is useful in predicting the likelihood of achieving positive histocytology at FOB. The overall CT prediction is superior to any of the individual CT features taken alone.Bungay, H. K. (2000). Clinical Radiology 55, 554-560.

Role of computed tomographic scanning of the thorax prior to bronchoscopy in the investigation of suspected lung cancer

BACKGROUND

Fibreoptic bronchoscopy (FOB) is the usual initial investigation of choice in patients with suspected endobronchial carcinoma, but it is often non-diagnostic. Once a positive diagnosis has been made, many patients undergo staging by computed tomographic (CT) scanning to assess the extent of the disease and its suitability for radical treatment. To determine whether initial CT scanning before FOB is a cost effective way of reducing subsequent unnecessary or unhelpful invasive diagnostic procedures, a study was undertaken in 171 patients with suspected endobronchial carcinoma.

METHODS

A randomised two group study was performed with all patients undergoing an initial CT staging scan. In group A the CT scans were reviewed before FOB, allowing cancellation or a change to an alternative invasive procedure if considered appropriate. In group B all patients proceeded to FOB with the bronchoscopist blinded to the result of the CT scan until after the procedure.

RESULTS

In group A six of 90 patients (7%) required no further investigations as the CT scan was either normal, consistent with benign disease, or consistent with widespread metastatic disease. Of the remainder, bronchoscopy was diagnostic in 50 of 68 (73%) in group A compared with 44 of 81 (54%) in group B (p = 0.015). Overall, a positive diagnosis was made after a single invasive investigation in 64 of 84 patients (76%) in group A compared with only 45 of 81 patients (55%) in group B (p = 0.005). Only seven of 90 patients (8%) in group A required more than one invasive investigation compared with 15 of 81 patients (18.5%) in group B. In patients with malignancy, bronchoscopy was more likely to be diagnostic in group A (50 of 56 patients (89%)) than in group B (44 of 62 (71%); p = 0. 012), and the diagnosis was more frequently made on the initial invasive investigation (group A, 63 of 70 (90%); group B, 44 of 62 (71%); p = 0.004). Because of the lower number of invasive procedures performed in group A than in group B, the cost of performing CT scans before FOB in all patients in group A would have equated to a projected cost of performing CT scans in 60% of patients after FOB in group B.

CONCLUSIONS

Performing initial CT thoracic scans before bronchoscopy in patients with suspected endobronchial malignancy is a cost effective way of improving diagnostic yield from invasive diagnostic procedures and occasionally may obviate the need for any further investigation.

Lung carcinoma

Lung cancer is the leading cause of cancer mortality in the United States. Imaging is helpful in the diagnosis of peripheral lung cancers and in the staging of lung neoplasms. CT may establish the benign nature of a solitary pulmonary nodule by detecting either benign types of calcification or fat. Contrast enhancement is a new and innovative method that can be used to distinguish benign from malignant peripheral lung lesions. Both CT and MR play important roles in the preoperative staging of lung carcinoma. Both have significant limitations, however, and surgical staging is often required.

Evaluation of the air bronchogram sign on CT in solitary pulmonary lesions

PURPOSE

Our goal was to evaluate the presence and the significance of the air bronchogram sign in solitary pulmonary lesions (SPL) on CT.

METHOD

One hundred thirty-two patients with SPL who underwent chest CT scans and had histological diagnosis were studied retrospectively. We reviewed all chest CT scans to assess for the presence of the air bronchogram sign in the SPL and recorded the distribution of this sign in malignant and benign lesions. The morphology of the aerated bronchi in the lesion and its significance in differential diagnosis were also evaluated.

RESULTS

Of 17 cases of benign lesions, only 1 (5.9%) had an air bronchogram; of 115 lung cancers, 33 (28.7%) had this sign (p < 0.05). The encased bronchi exhibited four morphologic patterns: normal, tortuous, ectatic, and cut-off. The morphology of the bronchus in the benign lesion was normal. However, bronchi in malignant lesions displayed all four types of morphology. The air bronchogram sign was seen in all histologic types of lung cancer (squamous cell 10, adenocarcinoma 9, bronchioloalveolar cell 12, small cell 1, non-small cell 1). Lesions of different sizes were noted to have air bronchograms, including those < 2 cm in diameter.

CONCLUSION

The CT air bronchogram sign in SPL is significantly more common in malignant than in benign lesions. The sign is seen in all lung cancer cell types and demonstrates varied bronchial morphology.