Who Should Get CT Screening for Lung Cancer? USPSTF Reveals

Who Should Get CT Screening for Lung Cancer?

• Adults 55-80 years with a 30 pack-year smoking history AND currently smoke
• Adults 55-80 years with a 30 pack-year smoking history AND have quit within the past 15 years

Screening Should Be Discontinued If:

• Once a person has not smoked for 15 years
• Once a person develops a health problem that substantially limits life expectancy or ability/willingness to have curative lung surgery

Reference:

Moyer VA on behalf of the U.S. Preventive Services Task Force. 

Moyer VA et al. Screening for lung cancer: U.S. Preventive Services Task Force Recommendation Statement. Ann Intern Med 2013 Dec 31; [e-pub ahead of print]. 

Updated Nomenclature of Vasculitides

A sagittal-curved-reformatted CT image of the aorta of a 31-year-old man demonstrate extensively calcified intima and focal narrowing of the mid/distal thoracic aorta, consistent with Takayasu arteritis.

Very recently, the international consensus conference addressed the revision of the nomenclature of systemic vasculitides as follows:

• LARGE-vessel vasculitis: Takayasu arteritis and giant cell arteritis
• MEDIUM-vessel vasculitis: polyarteritis nodosa, Kawasaki disease
• SMALL-vessel vasculitis: ANCA-associated vasculitis (microscopic polyangiitis, Wegener, Churg-Strauss), immune complex vasculitis 
• VARIABLE-vessel vasculitis: Behcet disease, Cogan syndrome
• SINGLE-ORGAN vascuiltis: cutaneous leukocytoclastic angiitis, primary CNS vasculitis, and others
• Vasculitis associated with systemic diseases such as lupus, rheumatoid arthritis and sarcoid
• Vasculitis associated with probable etiology (e.g., associated with viral hepatitis, drugs) 

Categorization by vessel size reflects the arteries those are predominantly affected. Vasculitis in each category can affect any size artery. 

Reference:

Jennette JC, et al. 2012 revised international chapel hill consensus conference nomenclature of vasculitides. Arthritis Rheum 2013;65:1-11.

Superficial Femoral Vein: Misleading Medical Nomenclature

Anatomy and Definition of Superficial Femoral Vein (SFV)

• SFV, as understood by vascular surgeons and radiologists, is a continuation of the popliteal vein. After joining the deep femoral vein, it becomes common femoral vein
• Superficial femoral vein is actually a "deep" vein

The Problem

• Most vascular surgeons and radiologists understand that SFV is a deep vein, but many physicians in other specialty or general practitioners do not
• Based on a survey of multispecialty groups, only 24% of physicians would give anticoagulants to patients having "acute thrombosis of the superficial femoral vein". There is a misperception of many physicians that SFV is superficial vein, therefore it would not be treated as deep vein thrombosis

Recommendations: Don't Use "Superficial Femoral Vein". Use "Femoral Vein"

• Current consensus developed by experts in phlebology officially established “femoral vein” as the vein that originates from the popliteal vein and courses in the femoral canal and bluntly discarded “superficial femoral vein” as an “unauthorized term" … because it is a deep vein 
• SFV is not in the official Terminologica Anatomica
• The other vein is "deep femoral vein" or "profunda femoris vein"
• Supported by International Interdisciplinary Consensus Committee on Venous Anatomical Terminology convened on September 8–9, 2001 (Nomenclature of the veins of the lower limbs: an international interdisciplinary consensus statement. J Vasc Surg 2002; 36:416-422)
•  Supported by Society of Interventional Radiology

Reference:
Hammond I. The superficial femoral vein. Radiology 2003;229;604-666 (link)

Nephrogenic Systemic Fibrosis Disappeared After Restrictive Use of Gadolinium?

According to a large (50 000+) retrospective cohort of patients who underwent contrast-enhanced MR examinations at a single academic institution pre- and post-adoption of strict gadolinium guidelines:-

• No new cases of nephrogenic systemic fibrosis (NSF) were diagnosed
• During the pre-guidelines adoption and transitional period, the incidence of NSF was 3 cases per 10,000 contrast-enhanced MRI
• After the adoption of guidelines, the incidence was 0 per all examinations

The Guidelines for Imaging Adult Patients

• Based on renal disease severity
• eGFR 60 or greater - GBCA can be administered as indicated
• eGFR 30-59 - weight-based dose of GBCA (0.2 mL/kg) can be administered with maximal dose of 20 mL allowed within 24 hours
• eGFR less than 30 - GBCA cannot be administered except in cases of medical necessity; informed consent required; nephrology consultation required; hemodialysis should be considered
• Very rarely that any patients with eGFR less than 30 would get contrast-enhanced MR exams (36 in 52 954 exams; 0.07%)

eGFR = estimated glomerular filtration rate; GBCA = gadolinium-based contrast agent

Reference:

Wang Y, Alkasab TK, Narin O, et al. Incidence of nephrogenic systemic fibrosis after adoption of restrictive gadolinium-based contrast agent guidelines. Radiology 2011; 260:105-111.

Predictors of Cervical Spine Fractures and Fracture Risk

Flow diagram (originally published by Blackmore CC, et al, Radiology 1999) demonstrating a prediction rule for determination of risk of cervical spine fracture in blunt trauma patients. Percentages indicate the risk of fracture for each group with 95% CIs. Area under the ROC curve = 0.87

Facts:

• Three common options exist to "clear" cervical spine in trauma patients: clinical evaluation, radiography or CT
• Canadian C-spine Rule (CCR) or NEXUS criteria are generally used by emergency physicians and trauma surgeons to determine which patients require imaging clearance
• Among patients who, based on CCR or NEXUS, need imaging clearance: an issue exists whether to choose x-ray vs. CT
• In general, CT is preferred for patients with moderate or high likelihood of having C-spine injury given its higher accuracy, cost-effectiveness and ease of performance. However, C-spine CT has not been tested as cost-effective among patients with low likelihood of C-spine injury - practice has been different from one place to another

According to Blackmore CC, et al

• We can stratify patients into groups of different fracture probabilities by using 4 predictors: severe head injury, high-energy cause, age and focal neurologic deficit
• Definition of severe head injury = intracranial hematoma, brain contusion, skull fracture or unconsciousness
• Definition of high-energy cause = high-speed MVC (greater than 30 mph), pedestrian struck by car
• Definition of moderate-energy cause = low-speed MVC, MVC at unknown speed, bicycle accident, motorcycle accident or fall
• Definition of focal deficit = those that could be in a spinal cord or spinal nerve distribution

Reference:

Blackmore CC, Emerson SS, Mann FA, Koepsell TD. Cervical spine imaging in patients with trauma: determination of fracture risk to optimize use. Radiology 1999; 211:759-765.

False Positives in the National Lung Screening Trial (NLST)

The tables show data from the NLST, with true and false positive screens at screening round #1, 2 and 3.

• NLST is a randomized control trial studying the effect of low-dose CT screening vs. CXR in reduction of lung cancer-specific mortality. The interim result had been announced in October 2010, which showed a 20% reduction in mortality of those who had screened with low-dose CT.
• Overall positivity rates (non-calcified nodule 4 mm or greater in size and other findings potentially related to lung cancer) for the NLST are 24.2% at low-dose CT, and 6.9% at CXR
• Of all positives, only 2-5% (at CT) and 4-7% (at CXR) of cases are truly lung cancer.
• Number of false positives are relatively high.
• To reduce false positives, systematic and multidisciplinary approach in establishing the regimen for low-dose CT lung cancer screening is needed.

Reference:

Gierada DS. RSNA 2010

ACR-Proposed Premedication Regimen to Reduce Contrast Reactions

According to the version #7 (2010) ACR Manual on Contrast Media, the following regimens are recommended for premedication of patients at risk for developing contrast reaction.

Elective Premedication

1. Prednisolone: 50 mg PO at 13 hours, 7 hours and 1 hour before contrast media injection, PLUS Diphenhydramine 50 mg IV, IM or PO 1 hour before contrast medium OR
2. Methylprednisolone 32 mg PO 12 hours and 2 hours before contrast media injection. An anti-histamine (as in option 1) can be added. If unable to take oral medication, use hydrocortisone 200 mg IV instead

Emergency Premedication

1. Methylprednisolone 40 mg or hydrocortisone 200 mg IV every 4 hours until contrast study required PLUS Diphenhydramine 50 mg IV 1 hour prior to contrast injection OR
2. Dexamethasone 7.5 mg or betamethasone 6 mg IV every 4 hours until contrast study PLUS diphenhydramine 50 mg IV 1 hour prior to contrast injection OR
3. Omit steroid entirely and give diphenhydramine 50 mg IV

"IV steroids have not been shown to be effective when administered less than 4 to 6 hours prior to contrast injection."

Reference:

ACR Manual on Contrast Media (7th version, 2010)

National Lung Screening Trial (NLST) Initial Results

What is the NLST?

• A multicenter, randomized controlled trial (RCT) comparing low-dose helical CT with standard chest radiography in the screening of men and women at risk for lung cancer
• Sponsored by the National Cancer Institute
• Starting in August 2002, the trial enrolled more than 53,000 participants, current or former heavy smokers, ages 55 to 74, at 33 sites over a 20 month period
• Participants were randomly assigned to received 3 annual screens with either low-dose helical CT or standard chest radiograph. Endpoint = death from lung cancer
• "Heavy smoker" = at least 30 pack-years and were either current or former smokers without signs, symptoms or history of lung cancer
• "Low-dose CT" = helical CT with 120-140 kVp, 40-80 mAs, detector collimation equal to or less than 2.5 mm

Findings To Date

• 354 deaths from lung cancer among participants in the CT arm of the study, v.s. 442 lung cancer deaths in the chest radiograph arm. 20% reduction in lung cancer mortality among participants screened with low-dose helical CT.
• All-cause mortality (deaths due to any factor) was 7% lower in those screened with low-dose CT than in those with chest radiograph

Reference:

National Lung Screening Trial Research Team. The National Lung Screening Trial: overview and study design. Radiology 2010, published online before print on November 2, 2010.

Radiologists Need to See Patients

The followings are summarized from the article "The Constantly Changing Field of Radiology: Maintaining Professionalism in an Era of Electronic Communication" by Alexander R. Margulis, MD.

PACS: Disruptive Innovation

• Good: streamlining imaging process, allowing almost instant availability of images and of reports, eliminating film loss, speeding up patient care
• Bad: reducing personal contact between radiologists and referring physicians, and radiologists and patients, making possible image interpretation from remote sites without any personal contact with treating physicians and little or no clinical information

The Problem

• "These developments threaten to change radiology into a commodity and radiologists, in patients' eyes, into nonparticipants in their care."
• Radiologists are not known by (or exist to) patients
• The notion endangers the role of radiologist as a physician, and the existence of radiology specialty

Suggestions

• See patients. "Radiologists need to see patients before imaging examinations to make it clear that they are supervising and will later interpret the examinations."
• "If possible and appropriate, they should even give patients preliminary readings."
• This can start in teaching centers, where faculty, fellows and/or residents take turns as "officer of the day" greet patients, determine examination protocols, and participate when the cases are reviewed

At the end of the article, Dr. Margulis predicts that "the radiologists of tomorrow will return to playing their full role as physicians. They will not only sit in front of PACS monitors interpreting images, but will see patients and remain continuously in touch with their clinical colleagues."

Reference

Margulis AR. The constantly changing field of radiology: maintaining professionalism in an era of electronic communication. Radiology 2010; 257:22-23.

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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