December 30, 2009

2009 Non-Small Cell Lung Cancer Staging System (3)

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As a radiologist, it may be easier to memorize "T" classification based on imaging appearance. The scheme below may be used as a guidance to stage these tumors, however a full text of the New Staging System should be reviewed for comprehensiveness.
  1. Peripheral mass abutting chest wall or diaphragm --- see if there is evidence of invasion of chest wall or diaphragm (T3)
  2. Peripheral mass, distal to lobar bronchus, completely surrounded by lung --- measuring size (less than 3cm = T1, 3-7cm = T2, more than 7cm = T3)
  3. Mass distal to 2 cm from the carina but proximal to lobar bronchus --- T2 by definition
  4. Endobronchial mass: distal to 2 cm from the carina = T2; within 2 cm from the carina = T3
  5. Central mass with postobstructive pneumonitis or atelectasis: lobar or segmental = T2;entire lung = T3
  6. Central mass abutting the mediastinum: invade mediastinal pleura, parietal pericardium = T3; diaphramatic paralysis (phrenic nerve involvement) = T3; invade heart, great vessels, trachea, esophagus, carina, vertebral body = T4
  7. Additional malignant lung nodules: same lobe = T3; ipsilateral different lobe = T4; contralateral = M1a
  8. Malignant pleural effusion or pleural nodule = M1a
Detterbeck FC, Boffa DJ, Tanoue LT. The new lung cancer staging system. Chest 2009:136;260-271.

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December 27, 2009

2009 Non-Small Cell Lung Cancer Staging System (2)

Axial CT images show a large mass (stars) in the left lower lobe with a large left pleural effusion with focal pleural thickening (arrowheads). The lung mass is better seen on a post-thoracentesis image. Transbronchial biopsy revealed adenocarcioma and pleural fluid cytology confirmed the presence of malignant cells. Based on the new staging system, this patient has at least M1a disease.

Based on multiple data sources and available clinical outcome (overall survival), additional schemes to stage NSCLC are implemented in this 7th edition. The subgroups and staging grouping are based on the overall survival as a major determinant. For example, overall survival of patients with "satellite nodule in the same lobe" is similar to those with T3 -- therefore it is classified as T3.

What Have Changed in the New Edition?
  • Additional "satellite nodule in the same lobe" now classified as T3 (previously T4)
  • Additional "satellite nodule in the different ipsilateral lobe" now classified as T4 (previously M1)
  • No change in N staging, but a new node map has been developed to address the issue of boundaries between different nodal stations
  • M staging is now subdivided into M1a and M1b to address significantly different prognosis: "contralateral pulmonary nodule (malignant)" and "pleural dissemination" now classified as M1a; distant metastasis as M1b
Detterbeck FC, Boffa DJ, Tanoue LT. The new lung cancer staging system. Chest 2009;136:260-271.

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December 24, 2009

2009 Non-Small Cell Lung Cancer Staging System (1)

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The latest (7th edition) version has been accepted by the UICC (Union Internationale Contre le Cancer) and the AJCC (American Joint Committee on Cancer) and was published earlier this year.

Non-Small Cell Lung Cancer (NSCLC) Staging System
  • Based solely on anatomic extent of disease (clinical symptoms or molecular behavior of tumors not included)
  • T = tumor; increasing T meaning larger tumor or invasive into more peripheral or central structures
  • N = lymph node location (not number)
  • M = metastasis
  • Two methods of staging = clinical (c) and pathological (p); clinical staging includes all information available PRIOR to any treatment (including invasive staging technique); pathological staging include information AFTER a resection
Sources of Data for the 7th Edition
  • 81,015 included cases from 45 sources in 20 countries
  • Only NSCLC included
  • Major determinant is the overall survival
Detterbeck FC, Boffa DJ, Tanoue LT. The new lung cancer staging system. Chest 2009;136:260-271.

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December 21, 2009

Peer Review in Radiology (2)

Scoring Language for Peer Review

By the American College of Radiology's RADPEER
  1. Score 1 = concur with interpretation
  2. Score 2 = discrepancy in interpretation/not ordinarily expected to be made (understandable miss)
  3. Score 3 = discrepancy in interpretation/should be made most of the time
  4. Score 4 = discrepancy in interpretation/should be made almost every time - misinterpretation of finding

How These Could Be Utilized?

  • For individual radiologists: maintenance of certification, ongoing quality improvement in diagnostic accuracy, opportunity for education
  • For institution: monitoring of radiologist performance as an individual and a group, tracking data over time, monitoring trends, conforming with requirements of several controlling agencies

Ideal Peer Review
  • Reveals opportunity for quality improvement
  • Ensures radiologist competence
  • Improves individual radiologist outcome
  • Should be unbiased, fair, balanced, timely, ongoing and nonpunitive
  • Should allow easy participation
  • Should have minimal effect on work flow
The most popular system in use at present is the American College eRADPEER

Mahgerefteh S, Kruskal JB, Yam CS, et al. Peer review in diagnostic radiology: current state and a vision for the future. Radiographics 2009;29:1221-1231.
2. Jackson VP, Cushing T, Abujudeh HH, et al. RADPEER scoring white paper. J Am Coll Radiol 2009;6:21-25.

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December 18, 2009

Posterior Acoustic Features of Breast Mass

Transverse ultrasound image of the breast shows an irregularly shaped hypoechoic mass (between calipers) with posterior attenuation of the acoustic transmission ("shadowing"). The shadowing obscures the posterior margin of the mass.

Posterior Acoustic Features
  • Attenuation characteristics of a mass with respect to its acoustic transmission
  • Four patterns: no posterior acoustic features, enhancement, shadowing and combined
Posterior Shadowing
  • Attenuation of sound beam deeper to a mass
  • Associated with fibrosis, with or without underlying carcinoma
  • DDx: scars, fibrous mastopathy and cancer with desmoplastic response
  • Helpful feature when present (suggesting above diagnoses)
  • Should be distinguished from "refraction or edge shadowing" which is a thin shadow seen at the edges of curved masses that is of no significance
Our case: invasive ductal carcinoma

Madjar H, Mendelson EB. The practice of breast ultrasound, 2nd edition, 2008.

December 15, 2009

Insall-Salvati Ratio for Assessment of Patella Height

Lateral view of the knee shows a method of measuring patella height in this patient who fell and was unable to extend the knee.

Facts: Insall-Salvati Method
  • Patella height expressed as a ratio of patellar tendon length (LT) to greatest diagonal length of the patella (LP)
  • Most commonly used method to assess patellar height in all degrees of flexion
  • LT = length of tendon = tendon origin at inferior patella to its insertion at the tibial tubercle
  • LP = length of patella = diagonal length of the patella
  • Normal = LT roughly is equal to LP, any variation more than 20% considered abnormal
  • LT:LP more than 1.2 = patella alta
  • LT:LP less than 0.8 = patella infera

Our case: LT:LP is greater than 2, this is patella alta due to traumatic complete patellar tendon rupture.

Scuderi GR. The Patella, 1995.

December 12, 2009

Acute Exacerbation of Idiopathic Pulmonary Fibrosis

Figure 1: Baseline chest radiograph of a patient with known idiopathic pulmonary fibrosis (IPF) shows bibasilar coarse reticular opacities, traction bronchiectasis and subpleural opacities.
Figure 2: Chest radiograph performed 3 months later when the patient developed acute dyspnea and hypoxemia shows new groundglass opacities superimposed on areas of pre-existing IPF.

Facts: IPF
  • Most common form of idiopathic interstitial pneumonias
  • Gradually progressive disease with steady worsening of symptoms, lung function and gas exchange
  • Median survival 3 years, no current treatment proven effective
Facts: Acute Exacerbation of IPF
  • Some patients with IPF develops acute respiratory deterioration, which is an unusual natural course of diseases
  • Idiopathic, no identifiable cause (infection, heart failure or pulmonary embolism)
  • This can occur at anytime during the disease course, and can be a presenting symptom of IPF
  • More common in men
  • Acute to subacute worsening of dyspnea, generally within 30 days, fever, cough, flulike symptoms, severe hypoxemia, respiratory failure requiring mechanical ventilation, low PaO2/FiO2 ratio
Imaging Features
  • Bilateral groundglass opacities with or without consolidation, superimposed on pre-existing IPF
  • Groundglass opacities can be peripheral, multifocal or diffuse (pathology from surgical lung biopsy usually shows diffuse alveolar damage)
  • Differential diagnosis on imaging: pulmonary edema, pneumonia superimposed on IPF
Diagnostic Criteria
  • Previous or concurrent diagnosis of IPF
  • Unexplained worsening or development of dyspnea within 30 days
  • HRCT with new bilateral groundglass abnormality and/or consolidation superimposed on a background reticular or honeycomb patter consistent with IPF
  • No evidence of pulmonary infection by endotracheal aspirate or bronchoalveolar lavage
  • Exclusion of alternative causes, including the following: left heart failure, PE, identifiable cause of acute lung injury
Collard HR, Moore BB, Flaherty KR, et al. Acute exacerbations of idiopathic pulmonary fibrosis. Am J Respir Crit Care Med 2007;176:636-643.

December 9, 2009


Figure 1: Lateral chest radiograph of a 76-year-old man with back pain shows destruction of mid-thoracic disc space (star).
Figure 2: Sagittal reformatted CT image (myelogram) shows destruction (star) of the disk space, opposing endplates and epidural extension of soft tissue (arrowheads) seen as filling defect on this myelographic study.

Facts: Spinal Infections
  • A spectrum of diseases - osteomyelitis (spondylitis), discitis, discitis-osteomyelitis, epidural abscess
  • Of all osteomyelitis, spine accounts for 2% - 4% of anatomic sites
  • When spinal infection involves thoracic spine, neurologic compromise is a concern
  • Patients at risk include diabetes, IV drug user, chronic delibitating disease, immunosuppression, recent vertebral surgery
  • Most common clinical presentation = axial back pain, constant, not relieved by rest (night pain is a red flag for infection or neoplasm)
  • Most spinal infections are due to bacterial infection (>50%, S. aureus); definitive diagnosis made by culture from blood or biopsy

  • Plain radiography: disc space narrowing (2-3 weeks of infection) --> endplate sclerosis (8-12 weeks) --> bony lysis --> vertebral body collapse resulting in localized kyphosis
  • CT: more bony details, with myelography it can delineate the degree of spinal canal encroachment
  • MRI: best imaging method to assess spinal infection; high sensitivity/specificity/accuracy (more than 90%)
  • Features: disc destruction (narrowing, signal change), endplate destruction, abscess, epidural extension, posterior element involvement
  • Think of TB if: late clinical presentation, extensive paravertebral abscess, relative preservation of disc, subligamentous spread
Our case: Discitis-osteomyelitis from Staphylococcus aureus.

1. An HS, Seldomridge JA. Spinal infections diagnostic tests and imaging studies. Clin Orthop Rel Res 2006;444:27-33

December 8, 2009

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Above picture: Singapore's Flyer by Paithoon Wichiwaniwate, M.D.

December 6, 2009

Zygomaticomaxillary Complex (ZMC) Fracture

Figures 1 & 2: Axial CT images show displaced fractures of the anterior and posterior walls of the right maxillary sinus (arrows), subtle fracture of the right zygomatic arch (short arrow) and a slightly angulated fracture of the lateral wall of the orbit (arrowhead).
Figure 3: 3D CT image shows a complete look of a ZMC fracture, including the fracture of the maxillary walls, zygomatic arch (arrow) and lateral orbital wall at the zygomaticosphenoid suture (arrowheads).

Facts: ZMC Anatomy
  • The zygomaticomaxillary complex is a quadrupled structure, meaning that it relates to 4 different bones of the skull: temporal bone, maxilla, frontal bone and skull base
  • Paired zygomas each have two attachments to the cranium and two to the maxilla.
  • Two major 'buttresses' of the ZMC are: upper transverse maxillary (across zygomaticomaxillary and zygomaticotemporal sutures) and lateral vertical maxillary (across zygomaticomaxillary and zygomaticofrontal sutures).
  • In fact, zygoma also relates posteriorly with the sphenoid bone of the skull base
Facts: ZMC Fractures
  • Fractures involving this quadrupled structures: anterior maxillary wall, posterolateral maxillary wall, zygomatic arch and lateral orbital wall
  • If fracture at the lateral orbital wall is angulated, it often increases orbital volume resulting in enophthalmos)
  • If fracture at the zygoma is comminuted, it often requires fixation via a scalp incision to fix the loss of cheek projection and increase facial width
  • Frequently missed ZMC fracture is at the temporal bone portion
Imaging Descriptions
  • Describe alignment of the zygoma and sphenoid at the lateral orbital wall fracture; angulation here reflects rotation deformity and increased orbital volume that needs to be fixed
  • Describe if the fracture along the zygomaticomaxillary suture traverses the infraorbital nerve foramen
  • Degree of comminution of zygomatic arch
  • Don't forget to look at the temporal bone portion of the ZMC for a fracture
Hopper RA, Salemy S, Sze RW. Diagnosis of midface fractures with CT: what the surgeon needs to know. Radiographics 2006;26:783-793.

December 3, 2009

H1N1 (Swine Flu) Pneumonia

Chest radiograph shows patchy airspace opacities in bilateral mid to lower lung zones in a patient infected with H1N1 virus (lab confirmed), admitted to the ICU. Subsequent CT (not shown) reveals similar findings without pleural effusions or lymphadenopathy.

  • First reported in Mexico in April 2009
  • Fatality rate 0.45%
  • Confirmed case = a person with an influenza-like illness with laboratory confirmed novel influenza A (H1N1) virus infection by one or more of the following tests: real-time RT-PCR, viral culture
  • Influenza-like symptoms = fever, cough, sore throat, body aches, headache, chills, fatigue
Radiographic Appearance
  • Initial exam is normal in nearly half of cases who had radiography
  • When initial exam is abnormal, the abnormality is patchy consolidation (50%), groundglass opacity or groundglass opacity with consolidation (25%)
  • Predominant location: lower lung zones (70%), diffuse (25%)
  • Pleural effusion not common (less than 10%)
  • Lymphadenopathy uncommon
Based on a single, uncontrolled study:
  • Patients with abnormal initial radiograph were associated with admission and severe disease
  • H1N1 infection was associated with a high rate of pulmonary embolism (36%) among patients admitted to the ICU

Agarwal PP, Cinti S, Kazerooni EA. Chest radiographic and CT findings in novel swine-origin influenza A (H1N1) virus (S-OIV) infection. AJR 2009;193:1488-1493.