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Solitary pulmonary nodule
This document discusses the imaging and characterization of solitary pulmonary nodules (SPNs). It defines an SPN and lists potential benign and malignant causes. Key imaging features that can help differentiate benign from malignant SPNs are described, including size, shape, edge characteristics, internal textures like calcification, fat and cavitation. The roles of CT, MRI, PET and other modalities are outlined. Determining the growth rate over time and performing biopsies are important for indeterminate nodules. Common benign entities like granulomas, hamartomas and infarcts are shown as examples.
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Solitary pulmonary nodule
- 1. IMAGING OF SOLITARY PULMONARYNODULE PRESENTOR : DR.NAVNI
- 2. DEFINITION • A solitarypulmonary nodule (SPN) is a round or oval opacity smallerthan 3 cm in diameter that is completely surrounded by pulmonary parenchyma and is not associated with lymphadenopathy, atelectasis, or pneumonia.
- 3. D/D OF SPN •MALIGNANT NEOPLASMS A. CARCINOMA B. LYMPHOMA C. LYMPHOPROLIFERATIVE DISEASES D. SOLITARY METASTATIC NEOPLASM (MELANOMA,OSTEOSARCOMA,PROSTATE, COLON,BREAST,RCC,TESTICULAR CARCINOMA) E. BRONCHIAL CARCINOID F. SARCOMA
- 4. • BENIGN NEOPLASMAND NEOPLASM LIKE CONDITION A. HAMARTOMA B. ENDOMETRIOMA C. MESENCHYMAL TUMOR
- 5. • INFECTIVE CAUSES A.GRANULOMA B. MYCETOMA C. ASPERGILLOMA D. ECHINOCOCCUS/HYDATID CYST E. FOCAL ROUND PNEUMONIA F. LUNG ABSCESS
- 6. • INFLAMMATORY A. RHEUMATOIDNODULES B. SARCOIDOSIS C. WEGENERS GRANULOMATOSIS
- 7. • AIRWAY ANDINHALATIONAL DISEASE A. MUCOID IMPACTION B. BRONCHIAL ATRESIA C. CYSTIC FIBROSIS D. PROGRESSIVE MASSIVE FIBROSIS E. LIPOID PNEUMONIA
- 8. • VASCULAR LESIONS A.HEMATOMA B. INFARCTION C. PULMONARY ARTERY ANEURYSM D. PULMONARY VEIN VARIX E. ARTERIOVENOUS FISTULA F. SEPTIC EMBOLISM
- 9. • CONGENITAL A. BRONCHOGENICCYST B. CCAM C. INTRAPULMONARY LYMPH NODE D. SEQUESTRATION
- 10. • IDIOPATHIC/MISCELLANEOUS A. AMYLOIDOSIS B.FLUID FILLED BULLA C. ROUND ATELECTASIS
- 11. SPURIOUS LESIONS ONCXR • NIPPLE SHADOW • PLEURAL BASED LESIONS • CHEST WALL LESIONS • SKIN NODULES • ARTIFACTS DUE TO CLOTHING • SCREEN ARTIFACTS Benign granuloma and primary bronchogenic carcinomas account for 80% of cases of SPN
- 12. IMAGING OF SPN •CHEST RADIOGRAPH • CT SCAN • MRI • FDG-PET / SPECT
- 13. MORPHOLOGICAL CHARACTERISTICS OF SPN 1.SIZE Size less than 9mm : difficult to appreciate on CXR but readily seen on CT DIAMETER MALIGNANCY RATE <1 CM 35 % 1-2 CM 50% 2-3CM 80% >3CM 97%
- 14. 2.SHAPE CARCINOMAS : IRREGULAR/LOBULATED/NOTCHED Lobulationoccurs in 25% of benign nodules. BENIGN : ROUND/OVAL/SMOOTH (SCARS/AREAS OF ATELECTASIS MAY APPEAR LINEAR OR ANGULAR)
- 15. 3.LOCATION • CENTRAL TUMORS: SMALL CELL CA, SQUAMOUS CELL CA • PERIPHERAL TUMORS : ADENO CA, LARGE CELL CA • METASTASIS USUALLY BASAL AND SUBPLEURAL • BENIGN LESIONS ARE EQUALLY DISTRIBUTED THROUGHOUT THE LUNG
- 16. 4.EDGE • MALIGNANT : IRREGULAR/SPICULATED/LOBULATED (radial extension of the tumor cells along the lymphatics, small airways or blood vessels) • BENIGN : SMOOTH/SHARP Metastases and carcinoid tumors have sharp, smooth edges 21% of well defined nodules are malignant
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- 19. • CORONA RADIATA/CORONA MALIGNA Presence ofspiculation associated with a nodule or a mass : fine,linear strands extending outward due to fibrosis surrounding the tumor/desmoplastic reaction
- 20. • PLEURAL TAIL Carcinomashave a thin linear opacity extending from the edge of a lung nodule to the pleural surface : due to fibrosis Can be seen in benign lesions too
- 21. • HALO SIGN Haloof ground glass opacity surrounding a nodule Seen in leukemic patients with invasive aspergillosis due to haemorrage, BAC due to lepidic spread of tumor, wegeners granulomatosis, tuberculoma
- 22. INTERNAL CHARACTERISTICS OFSPN 1. CALCIFICATION BENIGN NODULES
- 23. • HOMOGENOUS/UNIFORM/DIFFUSE/SOLID • DENSECENTRAL/BULLS EYE • CONCENTRIC RINGS/LAMINATED/TARGET : Tb, fungal granulomas • POPCORN : Hamartomas, cartilage tumors
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- 27. CALCIFICATION: MALIGNANCY • DYSTROPHIC: in areas of necrosis • DIFFUSE / AMORPHOUS • PSAMMOMATOUS : metastases from mucin secreting tumors such as colon , ovarian cancers • CENTRAL CALCIFICATION IN SPICULATED SPN • STIPPLED/PUNCTATE : due to engulfment of previous calcified lesion • ECCENTRIC DENSE : carcinoids, metastatic osteosarcoma, chondrosarcoma
- 28. Eccentric dense calcificationin right lower lobe carcinoid Amorphous calcification in non small cell ca lung
- 29. 2. FAT HAMARTOMA LIPIOD PNEUMONIA METASTATICLIPOSARCOMA
- 30. AREA OF FATATTENUATION IN NODULE : HAMARTOMA
- 31. 3. CAVITATION • LESIONWITH WALL THICKNESS < 4 mm -LIKELY BENIGN > 16 mm- LIKELY MALIGNANT 4-16 MM – INDETERMINATE • IRREGULAR – LIKELY MALIGNANT • THIN SMOOTH – LIKELY BENIGN
- 32. Benign cavitation Malignantcavitation
- 33. 4. PSEUDOCAVITATION • Desmoplasticreaction to the tumor distorts the airway causing narrowing and/or irregularity of the small bronchi in relation to the tumor • Seen as cystic glandular spaces within the mass
- 34. 5. AIR CRESCENTSIGN • Aspergilloma • Blood clot in a cyst • Complicated hydatid disease • Ca arising in a cyst • Rasmussen aneurysm • Mucus plug in cystic bronchiectasis • Pulmonary gangrene
- 35. 7. AIR FLUIDLEVEL Usually seen in benign lesions like lung abscess, infected cyst or cavity Intracavitary hemorrhage in cavitary carcinoma
- 36. 8. SATELLITE NODULES Smallnodules adjacent to larger nodule or mass Predictor of benign disease like granulomatous diseases Galaxy sign : satellite nodules in sarcoidosis Presence of satellite nodules in lung tumors is considered as locally advanced tumor
- 37. 9. FEEDING VESSELSIGN Small pulmonary artery leading directly to a nodule Seen in AVF, hematogenous metastasis, infarct
- 38. 10. POSITIVE BRONCHUSSIGN • A pulmonary lesion that directly abuts, narrows or occludes bronchial lumen is more likely to be malignant • Also seen in tuberculoma, pulmonary infarcts, Inflammatory masses • This sign helps in whether transbronchial or trans thoracic biopsy helps in histological diagnosis
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- 40. CONTRAST ENHANCEMENT • NODULEENHANCEMENT < 15 HU - S/O BENIGN LESION • NODULE ENHANCEMENT > 15 HU – S/O MALIGNANT LESION • SENSITIVITY - 95 -100% • SPECIFICITY -70 -93 %
- 41. 15 MIN DELAY •Malignant nodules: wash-in of >25 HU washout of 5-31 HU • Benign nodules: wash-in of < 25 H wash-in of >25 HU in combination with a washout of > 31 HU wash-in of > 25 HU and persistent enhancement withoutwashout
- 42. • The vascularsupply of most malignant pulmonary nodules is from the bronchial arterial system. Washout in the malignant nodules takes place via the bronchial veins. In the washout phase from the interstitial space, a near absence or substantial reduction of lymphatic flow is noted in malignant nodules. The retarded flow in the intravascular and interstitial spaces accounts for the retention of contrast medium in malignant nodules.
- 43. • In benignnodules, the outflow of contrast medium( washout) through the intravascular space in inflammatory processes takes place through relatively straight vessels with normal configuration and washout of contrast medium from the interstital space is accelerated by active lymphatic flow. Persistent enhancement is seen in some cases due to abundant degree of fibrosis as contrast remains in fibrotic portion for long time.
- 44. • Net enhancementof > 25 HU • Washout of 5-31 HU
- 45. • FALSE NEGATIVE Centralnecrosis Mucin producing tumors
- 46. GROWTH RATE ASSESSMENT •Volume doubling time is the time required for a lesion to double its volume VDT = t * log2 log Vt/Vo t= time difference Vt= volume at time t Vo= initial volume 1 VDT = 26% increase in the diameter of the nodule
- 47. • Absence ofgrowth over at least 2 yrs period : reliable Indicator of benignity • DT less than 1 month – Infection, infarction, lymphoma • DT 1 -18 months : bronchial carcinoma • DT more than 18 months : Granuloma, Hamartoma, Bronchial carcinoids • Doubling time for adeno , undifferentiated , Squamous cell CA is 7.3 , 4.1 , 4.2 months respectively.
- 48. • Slowest growingBACs have VDT of more than 3 years • Mets from testicular tumors and sarcomas have VDT of less than a month
- 49. COMPUTER AIDED DIAGNOSIS •Integrated computer system that supports nodule identification, analysis of nodule size, morphology and textural analysis of internal structure of nodule by analysis of high resolution CT data. • The CAD system recognizes opacity lesions surrounded by lung parenchymal attenuation as nodules. Therefore, nodules in the subpleural, fissural and costophrenic angle areas might be missed.
- 50. • Not helpfulto pick up lesions less than 4mm • Cannot replace the radiologist ; only supporting tool
- 51. ROLE OF DUALENERGY CT IN SPN • DECT can decompose enhanced structures into soft tissue and iodine • Allows for differentiation of calcification from enhancing tissue by subtraction of iodine component • By single scanning after iodine injection, we can measure the degree of enhancement without an additional non enhanced CT
- 52. ROLE OF CONTRASTENHANCED DYNAMIC MRI IN SPN • Dynamic contrast-enhanced MRI is helpful in differentiating benign from malignant solitary pulmonary nodules • Absence of significant enhancement is a strong predictor that a lesion is benign. • Presence of rim enhancement –granuloma , network or rim enhancement –hamartoma • Presence of homogeneous/heterogenous enhancement : malignancy
- 53. Network enhancement :hamartoma
- 54. • Primary lungcancers, time atmaximum enhancement ratio was 4 minutes or less • For all tuberculomas and hamartomas, time at maximum enhancement ratio was greater than 4 minutes or gradual enhancement occurred without a peaktime
- 55. Maximum relative enhancementratio of • >0.15 is the adopted threshold for a positive differentiation between malignant and benign SPN ( >0.15 = malignant ) • 0.80 is the adopted threshold between malignant and infective SPN ( <0.80 = Malignant )
- 56. • Dynamic MRIhas been used to assess tumor vascularity (microvesselcounts) and interstitium (degree of elastic and collagen fibers)
- 57. ROLE OF DW-MRIIN SPN SCALE ( study by Satoh et al ) 1. Nearly no signal intensity 2. Signal intensity between 1 and 3 3. Signal intensity almost equal to the spinal cord at thorasic spine 4. Higher signal than spinal cord SCORE OF 3 IS THRESHOLD FOR DIFFERENTIATING BENIGN AND MALIGNANT NODULES
- 58. Disadvantages of MRI •Poor resolution • Cardiac and respiratory motion artifacts • Difficulty in detecting lesion < 1 cm lesion • Not useful in peripheral SPN due to signal loss
- 59. ROLE OF FDG-PET •Malignant cells have upregulated metabolisms and proliferate rapidly.This results in marked uptake of FDG • False negative results due to - Carcinoids , BAC , Adeno with BAC component , SPN < 10 mm • False positive results are due to –Active TB , Histoplasmosis , Rhematoid nodules ,Aspergillosis , wegeners granulomatosis • Possibility of malignancy with negative FDG-PET is <5%
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- 61. FOLLOW UP (fleischner society and American family physicians )
- 63. ROLE OF SPECTIN SPN • The diagnostic ability of 201Thallium SPECT has been reported, with sensitivity, specificity, and accuracy of 85to 100%, 90 to 100%, and 85 to 100%, respectively. • Diagnostic accuracy for the pulmonary nodules over 2 cm in size between 201Tl SPECT and FDG-PET is almost the same.
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- 65. INDETERMINATE SPN • Transthoracicneedle aspiration biopsy for peripheral nodules • Fibreoptic bronchoscopy with transbronchial biopsy for endobronchial lesions • Video assisted thoracic surgery
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- 67. GRANULOMA • Commonest areTuberculomas • Single , 1-3 cm in diameter , well defined , smooth , regular outline • Commonest location close to pleural surface • Calcification - laminar , fleck like ,concentric, • Cavitation – rare • Satellite lesions sometimes seen • Commonly seen in upper lobes
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- 69. PULMONARY HAMARTOMA • Benignpulmonary mass containing connective tissue , cartilage , fat , smooth muscle , marrow , and bone • Most common location – periphery of the lung • X ray chest – spherical ,lobulated , well defined nodule • Popcorn like calcification • Fat density within the mass is a diagnostic feature
- 71. AVM • X ray– well circumscribed lesion with lobulated outline • X ray/CT - Feeding vessels and draining vein can be seen • It can be confirmed on CT • PULMONARY ANGIOGRAPHY RARELY INDICATED
- 72. AVM Lobulated,well marginated nodule inthe lower lobe Feeding artery (arrow) and an enlarged draining vein (arrowhead).
- 73. Nidus of malformation Pulmonaryangiogram helps confirm arteriovenous malformation. Note the early draining vein (arrows)
- 74. ROUND PNEUMONIA • Inflammatorypseudotumour • Some times pneumonic consolidation assumes a shape And density similar to pulmonary neoplasm • Careful study reveals irregular margin and air bronchogram • Common in children • May persists after recovery from infection
- 75. INFARCT • poorly marginated noduleperipherally in the lower lobe
- 76. VANISHING TUMOR • Sharplymarginated collection of pleural fluid contained either within an interlobar pulmonary fissure or in a subpleural location adjacent to a fissure • Can occur on minor fissure , oblique fissure • Most of them are < 4 cms
- 77. BRONCHIAL CARCINOID • Typicaltriad – Well defined ,round lobulated , lesion At the bifurcation Eccentric calcification
- 78. Nodule with eccentric calcifications(arrow) obstructing the posterior segmental bronchus of the right upper lobe. High-resolution CT scan shows a well-defined, round, partially endobronchial nodule (arrow) in the lateral subsegmental branch of the anterior segmental bronchus of the left upper lobe.
- 79. On a contrast-enhancedCT scan (mediastinal windowing), the nodule demonstrates marked contrast enhancement and mimics a vascular structure On a contrast-enhanced CT scan (mediastinal windowing), the nodule demonstrates marked contrast enhancement and mimics a vascular structure
- 80. ROUND ATELECTASIS • FOLDEDLUNG • Chronic atelectasis that resembles mass • X ray and ct – Peripherily located , wedge shaped opacity • Based against focally thickened pleura , commonly at lung base • Crow feet / comet tail of vesssels sweeping into the margin of this opacity • A rapidly forming pleural effusion produces an adjacent area of passive atelectasis • A groove of visceral pleura may infold into the area of atelectasis and come to surround a part of it
- 81. • Conventional tomographic scanof the chest in a lateral projection shows a large subpleural mass (arrowhead) in the right lower lobe of the lung. A curvilinear opacity (arrow), the comet tail sign, arises from the inferior pole of the mass and courses toward the hilum.
- 82. BIBLIOGRAPHY • LEARNING RADIOLOGY •Evaluation of solitary pulmonary nodule :RADIOGRAPHICS • TEXTBOOK OF RADIOLOGY AND IMAGING BY DAVID SUTTON • DIAGNOSTIC RADIOLOGY BY MANORAMA BERRY • Evaluation of solitary pulmonary nodule detected during computed tomography examination : POLISH JOURNAL OF RADIOLOGY • Evaluation of the Solitary Pulmonary Nodule : AMERICAN FAMILY PHYSICIANS • Solitary pulmonary nodule: A diagnostic algorithm in the light of current imaging technique : AVICENNA JOURNAL OF RADIOLOGY • Usefulness of the CAD System for Detecting Pulmonary Nodule in Real Clinical Practice: KOREAN JOURNAL OF RADIOLOGY • Dynamic MRI of Solitary Pulmonary Nodules: Comparison of Enhancement Patterns of Malignant and Benign Small Peripheral Lung Lesions: AJR
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