Brant

1
Brant Helms Resident Conference Series
Introduction
Omid Bendavid, M.D. UCI Radiology (lecture
adapted from Bara Mouradi, M.D.)
2
Reading is FUNdamental
3
Purpose and objectives

• For first year residents
• Read an entire general radiology textbook by half
  way thru the 1st year
• Learn to take boards-style cases
• For more senior residents
• Review the core curriculum
• Refresher course for written/oral boards

4
Format

• Didactics 45 minutes
• Hot Seat 10 minutes
• QA 5 minutes

5
Didactic session

• Outline of the assigned chapters and supplement
  where necessary
• Will go very fast (we can all read)
• PowerPoint presentation will be made available
  for review at your leisure
• Spend more time with images

6
Hot seat

• Each first year will get up to 90 seconds per
  case
• The moderator will follow-up with a brief
  discussion of the case
• More senior residents may be called upon to
  discuss cases afterwards

7
How to take a boards-style case

• BRIEF description of technique
• frontal view of the chest demonstrates
• Postgadolinium T1 images through the posterior
  fossa show
• Description of the findings
• a lytic expansile lesion with a narrow zone of
  transition eccentrically located in the proximal
  femoral metaphysis
• Differential diagnosis
• Top 3 usually sufficient
• Most likely diagnosis
• May be asked follow-up pimping questions (e.g.,
  management, recommendations)

8
How to take a boards-style case

• You may or, more likely, may not get a history
• Preferable to state, if the patient has a h/o so
  and so, then (if it makes a difference)
• May ask examiner for history
• You may ask for previous studies if available
• You may (and sometimes should) ask for/suggest
  follow-up study for further work-up
• The ddx for this lesion includes blah blah blah.
  A CT of the chest would be helpful
• Be ready to justify your recommendations (what
  will the CT add?)

9
Brant Helms Conference

• Chapters 12 13

Omid Bendavid, M.D. UCI Radiology (lecture
adapted from Bara Mouradi, M.D.)
10
Lobar segmental anatomy

• RUL
• Apical, posterior, anterior
• RML
• Medial, lateral
• RLL
• Superior
• Basilar anterior, lateral, posterior, medial
• Note most lateral is anterior basal
• LUL
• Apicoposterior, anterior
• Lingular superior, inferior
• LLL
• Superior
• Basilar anteromedial, lateral, posterior
• Note most lateral is anteromedial and most
  medial is posterior

11
Fissures

• Usually complete laterally and incomplete
  medially
• Major fissures have triangular configuration
  inferiorly, containing fat
• Accessory fissures
• Inferior accessory (10-20) most common, sep
  medial basilar from remaining basilar segments
• Azygous (0.5) invagination or right apical
  pleura by azygous vein, ending in azygous
  teardrop.
• Limits RUL consolidation from spread to azygous
  lobe and excludes PTX from apical position

12
Azygous fissure
13
Subsegmental anatomy

• Secondary pulmonary lobule
• Basic unit, visible on HRCT
• Subsegment supplied by 3-5 terminal bronchioles
  and separated from adjacent secondary lobule by
  interlobular septa
• Each terminal bronchiole supplies one pulmonary
  acinus
• (Thus 3-5 acini per secondary lobule)
• Pulmonary arterial branches run with airway
  branches in center of sec pulm lobule
  (bronchovascular bundle)
• Pulmonary veins run in interlobular septa

14
Pneumocytes

• Type I
• 95
• Flat squamous epithelium
• Gas exchange
• Incapable of mitosis
• Type II
• Repair source of new Type I pneumocytes
• Cuboidal cells
• Surfactant producing

15
Lymphatics

• Visceral pleural lymphatics roughly parallel
  margins of SPL (with pul veins)
• Parenchymal lymphatics adjacent to alveolar septa
  (juxta-alveolar lymphatics), course centrally c
  BVB
• 1 2 communicate via obliquely oriented
  lymphatics in central lungs (Kerley A lines)

16
Interstitium

• Peripheral interstitium subpleural interstitium
  interlobular septa
• Path Kerley B on CXR, thickened interlobular
  septa on HRCT
• Axial interstitium extends from mediastinum,
  envelops BVB, continues distally as
  centrilobular interstitium
• Path peribronchial cuffing
• Intralobular interstitium thin fibers bridge
  centrilobular and peripheral
• Path ground-glass opacification

17
Lung-lung interfaces

• Anterior junctional line contact of
  anterosuperior ULs in retrosternal space
• Seen on PA CXR if not a lot of mediastinal fat
• Posterior junctional line contact of
  posterosuperior ULs in retrotracheal space
• Hard to see on PA CXR see on CT
• Inferior posterior junctional line contact of
  azygoesophageal recess of RLL with preaortic
  recess of LLL in retrocardiac space
• Very hard to see on PA CXR see on CT

18
Lung-mediastinal interfaces

• Right side
• R paraesophageal
• SVC
• R paratracheal stripe
• Ant arch of azygous vein
• R paraspinal
• Azygoesophageal recess
• Lat margin of RA
• Confluence of R pulm veins (right border of LA)
• Lat margin of IVC

19
Lung-mediastinal interface

• Left side
• Lat margin of L subclavian artery
• Transverse aortic arch
• L sup intercostal vein (aortic nipple)
• AP window
• Lat margin of main PA
• Preaortic recess
• L paraspinal
• LA appendage
• LV
• Epicardial fat pad

20
Hilar anatomy
21
Chest Compartmentalization

• Most common method done anatomically
• Superior Thoracic Inlet area above a line
  drawn from the sternal angle anteriorly to the
  4th intervertebral disc space posteriorly
• Inferior further divided into
• Anterior Mediastinum Prevascular Space
  between the sternum but anterior to the heart,
  great vessels, trachea and esophagus
• Middle Mediastinum Vascular Space includes
  heart, great vessels/arch, trachea/main bronchi
• Posterior Mediastinum Postvascular Space
  behind the heart, to anterior to the spine,
  including the thoracic duct, hemi/azygous veins,
  desc aorta, neurovascular bundles

22
Thoracic inlet masses

• Thyroid
• Goiter, CA, etc.
• 80 anterior to trachea
• Parathyroid
• Can be ectopic in anterior mediastinum
• Lymphangioma
• Extension from neck

23
Thyroid goiter
24
Thyroid goiter
25
Anterior mediastinum

• The 4 Ts Mnemonic
• Thyroid see thoracic inlet masses
• Thymic tumors
• Teratoma, et al. (germ cell tumors)
• Terrible lymphoma
• Dont say T-cell lymphomathat is simply not
  correct!!!
• Mesenchymal tumors

26
Thymic tumors

• Thymoma
• 2nd most common ant med mass in adults
• 30-55 of pts c thymoma have myasthenia gravis
  10-20 of pts c myasthenia have thymoma
• May have cystic areas
• Ca in 25
• 30-50 malignant (i.e., beyond capsule)
• Other thymic tumors
• Thymic cyst, thymolipoma, thymic carcinoid,
  thymic hyperplasia, thymic CA, thymic lymphoma

27
Encapsulated Thymoma
28
Lymphoma

• Most common primary med mass in adults
• NHL or Hodgkins
• In Hodgkins, med is most frequent site of
  localized nodal mass in fact, if localized dz
  outside med/hila, suggest alternative dx
• Only 25 of Hodgkins is limited to med
• Untreated lymphoma almost never Ca
• Not mentioned in BH FDG-PET has revolutionized
  oncological imaging in general (lymphoma in
  particular). Modality of choice for detecting
  recurrence (more sensitive, specific, and
  accurate than CT)

29
Hodgkins Lymphoma
30
Germ cell tumors

• Teratoma
• Most common is cystic mature teratoma
• Solid teratoma usually malignant
• 10 in post mediastinum
• Ca in 30-50 (may be specific if tooth-like)
• Other GCTs
• ChorioCA, endodermal sinus tumor, embryonal cell
  CA, seminoma
• Seminoma most common malignant GCT
• Must exclude gonadal tumor to make dx of primary
  GCT look for retroperitoneal nodes

31
Mature teratoma
32
Mesenchymal tumors

• Lipoma
• Liposarcoma
• Leiomyoma
• Hemangioma (look for phleboliths)

33
Hemangioma
34
Middle mediastinum

• Lymphadenopathy
• Most common MM mass
• Majority malignant (bronch CAgtextrathoracic,
  lymphoma)
• Lymphoma 20 of med neoplasms in adults
• Usually bilateral but asymmetric
• In some pts c bronch CA (esp small cell), the
  primary CA is inconspicuous within nodal mass
• Written boards question re bx of med LNs
• Subcarinal transcarinal Wang needle bx
• Pretracheal mediastinoscopy

35
Middle mediastinum

• Benign LAN
• Sarcoid bilateral, symmetric, lobulated,
  discrete (LNs do not coalesce)
• TB/fungal usually also parenchymal dz, but may
  be isolated nodal esp in children
• Bacterial anthrax, bubonic plague, tularemia
• Castlemans (angiofollicular LN hyperplasia)
  middle and post med (and axillary) nodes that
  enhance intensely

36
Castlemans disease
37
Foregut and mesothelial cysts

• Congenital bronchogenic cyst
• Wall lined by resp epithelium. Diff to
  distinguish from enteric cysts on imaging
  (therefore, foregut cyst)
• 80-90 mediastinal close to carina
• Usually asx occ compress esoph or trach or
  secondarily infected or hemorrhage
• Pericardial cyst
• Most common in anterior cardiophrenic angle, RL
  21.
• 20 in superior mediastinum

38
Bronchogenic cyst
39
Middle mediastinum

• Pseudomasses
• Diaphragmatic hernias
• Vascular lesions

40
Posterior mediastinum

• Neurogenic tumors
• Schwannoma, neurofibroma, ganglioneuroma,
  ganglioneuroblastoma, neuroblastoma,
  paragangliomas (pheochromocytoma, chemodectoma)
• Esophageal lesions
• Enteric duplication cyst, diverticula, neoplasm,
  esoph dilatation, hiatal hernia
• Foregut cysts (Enteric neurenteric cysts)
• Enteric cyst is lined by enteric epithelium. When
  persistent comm c spinal canal (via canal of
  Kovalevski) assoc vertebral anomalies (ant
  spina bifida, etc.) neurenteric cyst

41
Ganglioneuroma
42
Posterior mediastinum

• Vertebral lesions
• Extramedullary hematopoesis, paraspinal hematoma,
  abscess, tumors

43
Diffuse mediastinal disease

• Acute mediastinitis
• Bacterial infection
• Etiologies esoph perf, CT surgery gt extension
  (neck, lung, pleura, pericard, spine)
• CXR wide sup med (66), pleural eff (50)
• Specific findings med air or AFL (uncommon)
• CT extraluminal gas, ST infilt of med fat,
  bulging of med contour
• Look for venous thromb, PTX, empyema
• DDx post-op changes if h/o CT surgery

44
Diffuse mediastinal disease

• Chronic sclerosing (fibrosing) mediastinitis
• Most commonly sec to Histoplasmosis
• Others TB, XRT, methysergide, idiopathic
• Most comm affected structure SVC (75)
• Most serious is obst of pul veins (pul edema)
• Less common manifestations tracheobronch tree,
  esophagus, pulm arteries
• CXR asym lobulated wide sup med (usually to
  right) if Histo, Ca LNs
• CT most com finding is enlarged Ca LNs ST
  density replaces med fat pos SVC syndrome

45
Fibrosing mediastinitis / SVC syndrome
46
Diffuse mediastinal disease

• Mediastinal hemorrhage
• CXR Med widening, pleural effusion
• CT ST (blood) density in mediastinum
• Mediastinal lipomatosis
• CXR smooth symmetric widening
• CT is definitive
• Pneumomediastinum
• Most common cause alveolar rupture
• Common in high pressure vent (ARDS/RDS)
• Clue may be air in neck
• Continuous diaphragm sign on CXR

47
Mediastinal hemorrhage / Traumatic aortic
pseudoaneurysm
48
Pneumomediastinum RMB rupture
49
Mediastinal lipomatosis
50
Unilateral hilar enlargement

• Malignant LAN bronch CA gt mets
• Infection LAN prim TB, postprimary TB in severe
  AIDS, fungal, bact (anthrax, plague, tularemia),
  viral (mononucleosis, measles)
• PA enlargement
• poststenotic dil from valvular or postvalvular
  pulmonic stenosis
• PA aneurysm, thrombus, tumor
• Bronchogenic cyst (unusual location)

51
Bilateral hilar enlargement

• Malig mets uncommon
• Most com solid tumors small cell, melanoma
• Lymphoma
• Leukemia (lymphocytic gtgt myelogenous)
• Infection
• TB/fungus (asymmetric)
• Anthrax Bil hilar/med LAN /- LL patchy airspace
  dz
• Sarcoidosis
• Usually symmetric
• 1-2-3 sign R paratracheal, R hilar, L hilar
• But on CT, usually other med nodes also
• Ca in 20 (punctate gt eggshell)

52
Bilateral hilar enlargement

• Silicosis / Berylliosis
• May be indistinguishable from sarcoid
• If eggshell Ca, suggest silicosis (less commonly
  seen in sarcoid, amyloid, Histo)
• Pulmonary arteries
• PAH (primary and secondary causes)

53
Sarcoidosis
54
Quiz

• If you dont know the answer, just say the
  mediastinum looks funny

55
Case 1
Invasive thymoma with pleural mets
56
Case 2
Extramedullary hematopoesis (Thalassemia)
57
Case 3
Pericardial cyst
58
Case 4
Thymolipoma
59
Case 5
Neuroblastoma
60
Case 6
Histoplasmosis, fibrosing mediastinitis, SVC
syndrome