October 30, 2009

FDG-PET and Multiple Myeloma

Figure 1: A radiograph of the right humerus (a part of skeletal survey) shows no abnormality in a 69-year-old man recently diagnosed with multiple myeloma.
Figure 2: FDG-PET shows multiple areas of hypermetabolism, including in the right humerus where the radiograph was negative. The majority of lesions in the ribs, scapulae and spine are not visualized on the skeletal survey.

Facts: Multiple Myeloma Staging (Durie-Salmon system)
  • Based on 4 factors: Hemoglobin, serum calcium, x-ray abnormality and amount of abnormal monoclonal immunoglobulin in blood or urine
  • Stage I: slightly decreased Hb, normal serum Ca, normal x-ray or only one area of bone damage, relatively small monoclonal immunoglobulin
  • Stage II: between I and III
  • Stage III: Hb <> 12 mg/dL, three or more areas of bone damage, large amount of monoclonal immunoglobulin
Multiple Myeloma Imaging Staging
  • Staging and monitoring is very important to management decision.
  • Studies of the National Oncologic PET Registry with 1300 myeloma patients showed that 36.5% of the time, treating physicians changed the intended management on the basis of PET/CT results
  • Traditional radiologic staging is to use skeletal survey but it can underestimate extent and magnitude of disease. Bone scan and gallium scan are unreliable.
  • Whole-body MRI has been used but it can be difficult to differentiate active disease from scar tissue, necrosis, fracture or benign disease
  • Several studies performed to assess the utility of FDG PET in staging and monitoring of multiple myeloma: they found that FDG PET is useful and superior to radiography in staging of newly diagnosed non-secretory myeloma (PET can upstage disease, can show bone/bone marrow abnormality in the absence of radiographic bone damage, can show sites of extramedullary disease), restaging and monitoring of non-secretory myeloma
  • FDG PET also can help differentiating multiple myeloma from monoclonal gammopathy of uncertain significance (MGUS)
FDG-PET has recently been approved for reimbursement by the U.S. Medicare & Medicaid Services.

1. Durie BGM, Waxman AD, D'Agnolo A, Williams CM. Whole-body 18-F-FDG PET identifies high-risk myeloma. J Nucl Med 2002;43:1457-1463
2. Dimopoulos M, Moulopoulos LA, Terpos E. A new pet for myeloma. Blood 2009;114:2007-2008.
3. The American Cancer Society. How is multiple myeloma staged? Link

October 27, 2009

Double Aortic Arch

A scout CT image of a 70-year-old woman shows subtle prominence of the right paratracheal soft tissue. There is slight narrowing the trachea at the level of the left aortic arch. The patient also has a large hiatal hernia.
Coronal reformatted CT image shows a double aortic arch, in which the right-sided arch is approximately about the same size as the left.

Facts: Double Aortic Arch
  • Most common symptomatic vascular ring
  • Ascending aorta divides anterior to the trachea into left and right arches; right arch typically is larger and more superiorly located than the left arch and passes posterior to the esophagus joining the descending aorta
  • Complete ring around trachea and esophagus may cause compression
  • Usually not associated with congenital heart disease (if it is, tetralogy of Fallot predominates)
  • Rarely presents in adulthood (as in our case)
  • Diagnosis often suggests by the presence of right sided aortic arch on radiography
  • Barium esophagography shows bilateral indentations of the esophagus in AP view
  • CT and MRI confirms the diagnosis. The size of each arch, degree of atresia (if present), branching patterns and degree of compression should be reported.

1. McMillan JA, et al. Oski's pediatrics: principles & practice, 4th ed, 2006.
2. Moss AJ, et al. Moss and Adam's heart disease in infants, children, and adolescents, 7th ed, 2007.

October 24, 2009

Buckle (Torus) Fracture of the Distal Forearm

Radiographs of the wrist of an 11-year-old girl following a fall show a subtle buckle fracture of the distal radius (arrows), clearly visible on the lateral view.

  • Common locations = wrist and ankle
  • 2nd most common fractures in infancy and childhood after epiphyseal-metaphyseal fractures
  • Falls on outstretched extremity

Imaging Features:
  • Rule -- cortex of a normal bone is always smooth and gently curving (always trace each cortex individually in all available views)
  • Buckle fractures can be a focal cortical slope, angle, kink, bump or break
  • Usually clearly visible on one view than another
  • When healed, sclerosis develops along the fracture line

1. Swischuk LE. Emergency imaging of the acutely ill or injured child. 4th ed, 2000.

2. Swischuk LE. Imaging of the newborn, infant, and young child. 5th ed, 2004.

October 21, 2009

Tubo-ovarian Abscess

Axial CT image of a young woman with left pelvic pain shows an enhancing, thick walled fluid collection in the left adnexa (arrows) inseparable from the left ovary. The right ovary is marked with an arrowhead.

Facts: Pelvic Inflammatory Disease
  • Young, sexually active, reproductive-aged women
  • Chlamydia trachomatis, Neisseria gonorrhoeae are the most common causative organisms
  • Risk factors include sexual activity at a younger age, several sexual partners, nonuse of barrier contraception
  • Complications include tubo-ovarian abscess (TOA; up to 30% of hospitalized patients with PID), perihepatitis
Clinical Diagnosis of PID
Abdominal tenderness, cervical motion tenderness and bilateral adnexal tenderness with at least one minor diagnostic criteria:
  • Documented cervical infection with C trachomatis or N gonorrhoeae
  • Mucopurulent cervicitis
  • Temperature > 38.3 C
  • Elevated erythrocyte sedimentation rate or C-reactive protein
  • Presence of an inflammatory mass on pelvic sonography
Imaging of TOA
  • Mass inseparable from the tube and ovary
  • Complex mass, fluid attenuation, thickened and irregular enhancing wall
  • Anterior displacement of the broad ligament may allow differentiation from pelvic abscesses from other sources (i.e. appendix, colon)
1. Lareau SM, Beigi RH. Pelvic inflammatory disease and tubo-ovarian abscess. Infect Dis Clin N Am 2008;22:693-708.

2. Potter AW, Chandrasekhar CA. US and CT evaluation of acute pelvic pain of gynecologic origin in nonpregnant premenopausal patients. Radiographics 2008;28:1645-1659.

October 18, 2009

Peer Review in Radiology (1)

What is Peer Review?

  • Most common method to assess performance of medical and clinical knowledge among radiologists
  • An assessment of adherence to standard of care of radiologists, typically involve diagnostic accuracy
  • Degree of interpretative agreement between radiologists is often used (perceived diagnostic features, correct interpretation and reporting)
Why Peer Review?
  • Ongoing quality assurance of diagnostic accuracy is important in radiology
  • It is also one of several crucial aspects in the maintenance of certification
  • It may ensure adherence to standard of care within an institution
  • It helps identifying opportunities for additional education, error reduction and self improvement
How to Peer Review?
  • In general, there are two methods: proactive or reactive
  • Proactive is to assign routine double reading of imaging studies by separate radiologists and compare the results
  • Reactive is by using discrepancy reporting, or by re-reviewing a previously read study during routine interpretation of a current study to evaluate the previous radiologist's interpretation.
  • Scoring is given for different degrees of discrepancy

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.

October 15, 2009

Climate Change and A Radiologist

Since today is a Blog Action Day and the theme of this year is 'Climate Change', we at RiTradiology.com are requested to discuss about this topic. If you happen to visit any other blogs today, you probably will notice that everyone is talking about the climate change. Don't get bored yet, it is only a day.

How did I get materials for today's post? I began by googling 'radiologist green' and found several links of Drs. Green who are radiologists. I won't blame google for this and won't try Bing (because it's not google) either. I changed my keywords to 'radiologist climate change'. The article in Radiology Business Journal came up "The Invisible Radiologist Meets the New Math, Climate Change and Business 101". You can click the link to view the full online article; it talks about the medical/radiologic climate change with a new healthcare bill on its way to change the face of healthcare in the United States. I'm sorry I'm not going to touch on this.

Let's get back to our business, what do you do - as a radiologist - to make the world around you greener? Here are my suggestions. [please note that these are not professional recommendations by any means]
  • Change to digital imaging (filmless environment helps keep our planet green, no more printing!)
  • Dimming the light in the reading rooms (less energy consumption, also following a good practice)
  • Image more appropriately (picking the right examination for the right clinical question) and less frequently
  • Give less radiation to our patients (also saving energy consumption of CT scanners)
You are welcome to add your thoughts in the comment section below.

Have a good day!

RiTradiology.com team

October 12, 2009

Nuss Procedure for Pectus Excavatum

PA and lateral chest radiographs show a retrosternal Nuss bar in a patient following Nuss procedure. Note the retrosternal location (arrow) and the intercostal attachments (arrowheads) of the bar.

Facts: Nuss Procedure
  • New approach to repair pectus excavatum
  • Simple technique with better cosmetic results; aiming to elevate the deepest part of the depression
  • Done by placing a retrosternal metallic bar through small incisions in the intercostal space. The bar penetrates the pleural cavity at the hinge point at either side.
  • Several types of bars available to choose depending on the morphology of pectus excavatum
  • It is important for surgeon to elevate the deepest part of the depression, which is not necessarily the center of the sternum!
  • Most common = pneumothorax
  • Followed by: bar displacement, seroma, pleural effusion, pericardial effusion
  • Bar displacement can be: 1) flipping (most common), 2) lateral sliding, 3) backward shift
Park et al. The Nuss procedure for pectus excavatum: evolution of techniques and early results on 322 patients. Ann Thorac Surg 2004;77:289-295.

October 11, 2009

Updated ACR Appropriateness Criteria

The American College of Radiology (ACR) Appropriateness Criteria has recently been updated and published online on September 30, 2009.

The "Appropriateness Criteria" is evidence-based guidelines for physicians and providers to help making the most appropriate imaging or treatment decision for a given clinical condition. This latest release include 167 topics with over 800 variants addressing various radiology subspecialty, including radiation oncology.

Click here to go to the ACR Appropriateness Criteria page.

October 9, 2009

Pectus Excavatum

An axial CT image shows a measurement of Haller index (A = transverse diameter, B = anteroposterior diameter of the inner chest wall), which is approximately 3.4 indicating severe pectus excavatum.

Facts: Pectus Excavatum
  • Congenital chest wall deformity "caved-in" or concave appearance in the anterior chest wall
  • Most common type of congenital chest wall deformity (90% of all), followed by pectus carinatum (approximately 5%)
  • Most cases are diagnosed within the first year of life
  • Worsening during rapid bone growth (early teenage)

  • Easy to make on a clinical ground
  • Radiography and chest CT performed to determine the need of surgery, and for surgical planning
  • Haller index is used to grade the severity (Haller index = transverse chest diameter divided by anteroposterior diameter)
  • Haller index > 3.2 correlates with severe deformity that requires surgery
  • Two morphologic classifications of pectus excavatum: 1) symmetric (center of the sternum is the same as the center of depression 2) asymmetric (center of the depression is off to one side i.e. not at the same location as the center of the sternum). Chest CT is best used to show the morphology and for surgical planning
1. Park HJ, Lee SY, Lee CS, et al. The Nuss procedure for pectus excavatum: evolution of techniques and early results on 322 patients. Ann Thorac Surg 2004;77:289-295.
2. Hebra A. Pectus excavatum. In: E-medicine, updated Sep 21, 2009.

October 6, 2009

Retroperitoneal Lymphadenopathy

Axial and coronal reformatted CT images show bulky retroperitoneal lymph nodes (arrows) and mesenteric lymph nodes (arrowheads). The lymph nodes are homogeneously enhanced and appear to surround the vessels.

Facts: Retroperitoneal Lymphadenopathy
  • Diagnosed on CT or MRI by nodal enlargement that may be accompanied by displacement of adjacent structures
  • Upper limit of normal at this location = 10 mm
  • 8-10 "multiple" lymph nodes should be viewed with suspicion
  • Large differential possibilities, including infection/inflammation and neoplasm.
  • Generally, benign conditions do not exhibit massive conglomeration of lymph nodes
Differential Diagnosis:
  • Infection: TB, MAI
  • Inflammation: sarcoidosis, Castleman disease, bulky form of retroperitoneal fibrosis
  • Neoplasm: lymphoma, metastasis
  • Imaging features can significantly overlapped and it can be difficult to tell one way of the other. Biopsy is usually required for definitive diagnosis.
Potential Clues:
  • Immunocompromised patients -- think of mycobacterial infection, lymphoma, Kaposi's sarcoma (esp. if there is cutaneous tumor), progressive generalized lymphadenopathy syndrome (lymphadenopathy in other locations)
  • Multiple lymph node stations, homogeneous nodes, hepatosplenomegaly -- think of lymphoma
  • Hyperenhancing -- think of hypervascular metastasis or Castleman disease
Our case: Retroperitoneal lymphadenopathy due to squamous cell carcinoma metastasis from head and neck cancer.

1. Warshauer DM, Lee JKT, Patel H. Retroperitoneum. In: Lee JKT et al (eds), computed body tomography with MRI correlation, 4th edition, 2006.
2. Chapman S, Nakielny R. Aids to radiological differential diagnosis, 4th ed, 2003.

October 3, 2009

Posterior Reversible Encephalopathy Syndrome (PRES)

Fig. 1: Axial non-contrast CT image in a 57-year-old hypertensive man shows ill-defined areas of low attenuation in the posterior occipital lobe (arrows).
Fig. 2: Axial FLAIR MR image confirms the abnormality in cortical and subcortical white matter of the posterior aspect of the occipital lobes (arrows), relative sparing of the paramedian occipital regions. There is no contrast enhancement or restricted diffusion.

Facts: Posterior Reversible Encephalopathy Syndrome (PRES)
  • Usually reversible neurologic syndrome presenting with reversible headache, altered consciousness or vision loss accompanied by reversible imaging abnormalities
  • Related to hypertension, eclampsia and preeclampsia and immunosuppressive medication (and several other causes have been described)
  • Believed to be due to hyperperfusion state with blood brain barrier breakthrough
Typical Imaging Appearances
  • CT is often abnormal at the time of presentation. MRI shows more lesions and extent.
  • Cortical or subcortical edema
  • Preferential involvement of posterior aspect of the lobes, particularly parieto-occipital lobes (gradient effect present)
  • Sparing of calcarine and paramedian occipital lobe structures
  • Usually bilateral
Our case: PRES (typical imaging appearance)

1. Hinghey J, Chaves C, Appignani B, et al. A reversible posterior leukoencephalopathy syndrome. New Eng J Med 1996;334:494-500.
2. McKinney AM, Short J, Truwit CL, et al. Posterior reversible encephalopathy syndrome: incidence of atypical regions of involvement and imaging findings. AJR 2007;189:904-912.