Measuring Radiologist Productivity

What is Productivity?

• "Hourly worker output"
• Productivity in physician practice reflects efficiency with which work is performed
• Productivity gain closely correlates with health of overall economy, rising living standards and growth of real wages

Why Measuring Productivity?

• Practice of radiologists has changed from traditional, small (less than 10 members) group to larger groups with subspecialization.
• Increase employment of part-time radiologists
• These factors result in difference in case mix, on-call demands and increased difficulty of informal monitoring of each radiologist's work

How?

• Several methods exist including using revenue, hours worked, volume of examination and Relative Value Units (RVUs)
• Because RVUs combine many facets of other methods (volumes, hours) and easily/timely availability, it is most widely used as an indicator of radiologist productivity
• RVUs are work component of professional Resource-Based Relative Value Scale per time period. Each Current Procedural Terminology (CPT) code is assigned an RVU for physician work (wRVU) as well as RVU for practice and malpractice expenses.
• wRVUs are intended to reflect time and effort expended by radiologists to perform services

Reference Authors' Recommendations

• Quoted from the below reference, authors are from Mass. General Hospital in Boston and Sloan School of Management at MIT
• RVUs seem to be the most reasonable means to evaluate radiologist productivity, however practices may elect to monitor more than one productivity measures because no single measure is perfect
• Authors recommend measuring "team-based" RVUs rather than individual's. This is to value members who perform duties with lower RVU assignment or no RVUs (i.e., consultation, conference participation, administration, teaching)
• Productivity measures reporting should be coupled with quality metrics

Reference:

Ding A, Saini S, Berndt ER. Radiologist productivity: what, why, and how. JACR 2009;6:824-827.

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CT Radiation Exposure in Real Clinical Practice and Cancer Risk Estimation

Two recent studies published in the Archives of Internal Medicine in December 2009 could serve as an eye opener for every physicians ordering CT scans as well as radiologists.

Smith-Bindman et al collected CT dose data of 11 most common CT study types performed in 4 hospitals in San Francisco Bay Area. They found that there were wide variations in dose within each study type and between different types. For example, routine chest CT dose ranged from 2 to 24 mSv, routine abdomen-pelvis CT with IV contrast dose ranged from 4-45 mSv. Median effective doses for each exam were higher than they were commonly quoted in the literature, for example, 8-10 mSv is common quote for a chest CT examination. They also estimated the risk of developing cancer related to CT in several patient groups according to patient's age at the time of CT. Based on their calculation, 1 in every 80 women who undergo a chest CT for suspected pulmonary embolism at age 20 will develop cancer. Similarly, 1 in every 270 women who undergo coronary CT angiography at age 40 will develop cancer.

Berrington de Gonzalez et al utilized Medicare claim data and IMV Medical Information Division survey to project estimated age-specific cancer risk from CT studies performed in the U.S. in 2007. Excluding CT studies done for cancer diagnosis and within the last 5 years of life, 2% (29,000) excess cancers caused by CT scans in 2007 were predicted.

What is needed?

1. Optimization and standardization of CT protocols and techniques to limit radiation
2. Reduction of number of CT scans
3. Collection of dose information at patient level to educate patients and health care providers about radiation exposure

References

1. Smith-Bindman R et al. Radiation dose associated with common computed tomography examinations and the associated lifetime attributable risk of cancer. Arch Intern Med 2009; 169:2078. PubMed abstract

2. Berrington de González A et al. Projected cancer risks from computed tomographic scans performed in the United States in 2007. Arch Intern Med 2009; 169:2071. PubMed abstract

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Adrenal Mass Characterization

Fig 1: Precontrast axial CT image shows a 3-cm left adrenal mass with an attenuation of 1.3 HU, indicating a lipid-rich adenoma.
Fig. 2: Precontrast axial CT image of a different patient shows a right adrenal mass with an attenuation of 20.8 HU, which is indeterminate. Note that the region of interest (ROI) measurement should cover at least half the size of the mass.

Facts:

• Lipid-rich adenomas contain intracellular fat (microscopic level) that can be shown on CT as low attenuation
• Adenomas wash out contrast more rapidly than malignant masses
• Extension into IVC suggests malignancy, particularly adrenocortical carcinoma

Adrenal Mass: Adenoma Vs. Others

1. Size: can not be definitively used to distinguish benign from malignant adrenal masses. In general, patients without known malignancy and a mass greater than 5 cm, surgical resection is advised
2. Precontrast attenuation: less than 10 HU (sensitivity 70%, specificity 98%)
3. Postcontrast (venous phase) attenuation: at 60-70 second delay after contrast injection, absolute enhancement of a mass of > 110-120 HU likely pheochromocytoma
4. Delayed postcontrast attenuation: used to calculate absolute and relative percentage washout. Absolute Percentage Washout (APW) >60% or Relative Percentage Washout (RPW) >40% suggests an adenoma.

Our cases: Both cases are adrenal adenomas, the first is a lipid-rich adenoma and the second is a lipid-poor adenoma (confirmed with dynamic scans, not shown).

Reference:

Johnson PT, Horton KM, Fishman EK. Adrenal imaging with multidetector CT: evidence-based protocol optimization and interpretative practice. RadioGraphics 2009;29:1319-1331.

Ductal Carcinoma in Situ

Magnification mammography shows two separate foci of pleomorphic microcalcifications (arrows) in the left breast. There is no associated mass, architectoral distortion or lymphadenopathy.

Facts: Malignant Calcifications on Mammography

• Small -- less than 0.5 mm
• Clustered, segmental
• Character -- fine granular, fine linear, branching (casting) or pleomorphic

Ductal Carcinoma in Situ (DCIS)

• Malignant ductal epithelium without disruption of the underlying basement membrane; normal ductal architecture is preserved.
• Pathological distinguishing feature from lobular CIS is the presence of intercellular cohesion
• Thought to represent early stage of breast cancer
• Several types: comedo, solid, cribiform, clinging (flat-type), mixed
• Grading based on nuclear atypia and necrosis is predictive of prognosis
• Patients are usually asymptomatic

Mammographic Findings

• Cluster(s) of malignant microcalcifications
• If an area of calcifications is larger than 2.5 cm, high likelihood of microinvasion
• If seen with a mass, it could be an intraductal component of an invasive cancer that may require surgical removal and specimen radiography to ensure complete removal
• Mammography should be thoroughly evaluated for multicentric (tumors in different breast quadrants) and multifocal (same quadrant) disease

Our case: Ductal carcinoma in situ, multifocal disease

References:

1. Kopans DB. Breast imaging, 3rd ed, 2007.

2. Conant EF, Brennecke CM. Breast imaging case review series, 2nd ed, 2006.

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Ectopic Origin of Right Coronary Artery

Axial CT image shows an ectopic origin of the right coronary artery (arrow) arising from the left cusp and passes between the ascending aorta and the right ventricular outflow tract in the "intraseptal" course.

Coronary Artery Anomalies

• 1% of all patients undergoing cardiac catheterization
• Three types: ectopic origin from a coronary cusp (like our case), absent coronary artery, ectopic origin from a main pulmonary artery
• 20% causes life threatening symptoms such as arrhythmias, syncope, myocardial infarction or sudden death
• MDCT can clearly show the origin and course of several forms of anomalous coronary artery.

Anomalous Coronary Crossing Between Aorta and Main Pulmonary Artery/RV Outflow

• Either left coronary originating from the right cusp (sinus) or right coronary arising from the left cusp (sinus), if it courses between the aorta and MPA -- it is called "intervascular course" and is associated with poor outcome.
• If it courses between the aorta and RV outflow tract inferior to the plane of the pulmonic valve, it is "intraseptal course" and considered "comparatively benign"

Reference:

Datta J, White CS, Gilkeson RC, et al. Anomalous coronary arteries in adults: depiction at multi-detector row CT angiography. Radiology 2005;235:812-818.

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