| OBJECTIVE:To evaluate the CT features of typical PFN,atypical PFN and non perifissural nodules(PFN),and to describe the discriminating features to distinguish them.MATERIALS AND METHODS:This study included the CT scan for 148 patients who had fulfilled the CT criteria for typical PFN,atypical PFN and Non PFN.These Perifissural nodules were categorized according to location(lobar and segmental),shape(triangular,oval,round,polygonal and rectangular),manualy measuring long axis diameter in cm,margin(smooth or irregular),appearance(homogeneous and inhomogeneous),relationship with fissure,presence and absence of feeding vessel,air component and septal connection.For scanning we namely used SIEMENS SOMATOTOM definition&sensation Flash CT with 120kVp,100-200 mAs pitch of 0.85-1.4 and slice thickness of 1-2.5mm.CT parameters such as window width and window level also varied from 1000-1200HU and-600 to-700HU respectively.For statistical analysis,the level of significance was considered to be p value less than 0.05.RESULTS:In retrospective analysis of 148 patients revealed 199 Perifissural nodules,out of which 175 were typical nodules and 13 were atypical nodules and 11 were non-PFN.67 males;mean age of 64.20years ± 11.50 standard deviation,age range:40-88 years and 57 females mean age of 62.72 years ± 11.02 standard deviation and age range of 34-81 had Typical PFN.7 males mean age of 71.01 years ± 18.17 standard deviation and age range of 34-88 years and 6 females mean age of 70.09 years± 12.01 standard deviation and age range of 54-88 years had Atypical PFN(out of the 7 males,4 males had atypical nodules together with typical nodules).3 males mean age of 49.44 years ± 12.00 standard deviation,age range of 25-55 years and 8 females of mean age of 58.11 years ± 13.01 standard deviation and age range of 33-74 was detected in Non PFN.The mean size of the typical PFN is 0.45cm ±0.16cm standard deviation,mean size of atypical PFN is 0.42cm ± 0.14 cm standard deviation,and mean size of Non PFN is 0.64cm ± 0.16cm standard deviation.The mean size of the 11 Non PFN(0.64cm P<.001)was larger than that of the 11 atypical PFN(0.42cm)and 175 typical PFN(0.45cm).73/199(37.03%)typical nodules were located at right oblique fissure,19/199(10.04%)typical PFN were located at right horizontal fissure and 83/199(42.01%)typical nodules were located at left oblique fissure.41/175(23.42%)typical PFN were most commonly located at the middle part of left oblique fissure.There is also significant association between shape and Perifissural nodules(p<0.001).For typical and atypical PFN an oval shape(P<0.015)and a triangular shape(P<0.014)showed an significant association.For typical and atypical nodules there was also significant association with presence of septal connection(P<0.001).Round shape(P?0.001)and presence of air component(P?0.001)showed a significance association with Non-PFN.Multiple logistic regression analysis showed septal connection as the discriminating feature between typical PFN,atypical PFN and Non PFN.CONCLUSION:In conclusion,PFNs are frequently encountered in lung cancer screening or as in incidental findings.We found that most of the PFN are located below the level of carina.And especially in bilateral oblique fissure and the middle part of left oblique fissure.Typical and atypical PFNs are mostly triangular and oval shape and have smooth margins and they are most likely to be benign and represent intrapulmonary lymph nodes.Non-PFN is mostly round in shape and has irregular margins with speculations and they most likely represent malignancy.Finally we found out that the most discriminating feature between typical and atypical PFN and Non PFN is the presence of septal connection. |
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