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.

References:

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

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)

Imaging

• 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.

References:

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.

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.

Facts:

• 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

References:

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.

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)

References:

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.

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

Reference:

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.