• “ Recent software developments enable interactive, real-time axial, 2D and 3D CT display on an iPad by cloud computing from a server for remote rendering. The purpose of this study was to compare radiologists' interpretative performance on the iPad to interpretation on the conventional picture archive and communication system (PACS). Fifty de-identified contrast-enhanced CT exams performed for suspected pulmonary embolism were compiled as an educational tool to prepare our residents for night call. Two junior radiology attendings blindly interpreted the cases twice, one reader used the PACS first, and the other interpreted on the iPad first. After an interval of at least 2 weeks, the cases were reinterpreted in different order using the other display technique. Sensitivity, specificity, and accuracy for identification of pulmonary embolism were compared for each interpretation method. Pulmonary embolism was present in 25 patients, ranging from main pulmonary artery to subsegmental thrombi. Both readers interpreted 98 % of cases correctly regardless of display platform. There was no significant difference in sensitivity (98 vs 100 %, p = 1.0), specificity (98 vs 96 %, p = 1.0), or accuracy (98 vs 98 %, p = 1.0) for interpretation with the iPad vs the PACS, respectively. CT interpretation on an iPad enabled accurate identification of pulmonary embolism, equivalent to display on the PACS. This mobile device has the potential to expand radiologists' availability for consultation and expedite emergency patient management.”
  The iPad as a mobile devise for CT display and interpretation: diagnostic accuracy for identification of pulmonary embolism
  Johnson PT, Zimmerman SL, Heath D, Eng J, Horton KM, Scott WW, Fishman EK
  Emerg Radiol 2012 Mar 27
• “ Recent software developments enable interactive, real-time axial, 2D and 3D CT display on an iPad by cloud computing from a server for remote rendering. The purpose of this study was to compare radiologists' interpretative performance on the iPad to interpretation on the conventional picture archive and communication system (PACS). CT interpretation on an iPad enabled accurate identification of pulmonary embolism, equivalent to display on the PACS. This mobile device has the potential to expand radiologists' availability for consultation and expedite emergency patient management.”
  The iPad as a mobile devise for CT display and interpretation: diagnostic accuracy for identification of pulmonary embolism
  Johnson PT, Zimmerman SL, Heath D, Eng J, Horton KM, Scott WW, Fishman EK
  Emerg Radiol 2012 Mar 27
• “Fifty de-identified contrast-enhanced CT exams performed for suspected pulmonary embolism were compiled as an educational tool to prepare our residents for night call. Two junior radiology attendings blindly interpreted the cases twice, one reader used the PACS first, and the other interpreted on the iPad first. After an interval of at least 2 weeks, the cases were reinterpreted in different order using the other display technique. Sensitivity, specificity, and accuracy for identification of pulmonary embolism were compared for each interpretation method. Pulmonary embolism was present in 25 patients, ranging from main pulmonary artery to subsegmental thrombi. Both readers interpreted 98 % of cases correctly regardless of display platform. There was no significant difference in sensitivity (98 vs 100 %, p = 1.0), specificity (98 vs 96 %, p = 1.0), or accuracy (98 vs 98 %, p = 1.0) for interpretation with the iPad vs the PACS, respectively.”
  The iPad as a mobile devise for CT display and interpretation: diagnostic accuracy for identification of pulmonary embolism
  Johnson PT, Zimmerman SL, Heath D, Eng J, Horton KM, Scott WW, Fishman EK
  Emerg Radiol 2012 Mar 27
• “CT interpretation on an iPad enabled accurate identification of pulmonary embolism, equivalent to display on the PACS. This mobile device has the potential to expand radiologists' availability for consultation and expedite emergency patient management.”
  The iPad as a mobile devise for CT display and interpretation: diagnostic accuracy for identification of pulmonary embolism
  Johnson PT, Zimmerman SL, Heath D, Eng J, Horton KM, Scott WW, Fishman EK
  Emerg Radiol 2012 Mar 27
• “ Recent software developments enable interactive, real-time axial, 2D and 3D CT display on an iPad by cloud computing from a server for remote rendering.”
  The iPad as a mobile devise for CT display and interpretation: diagnostic accuracy for identification of pulmonary embolism
  Johnson PT, Zimmerman SL, Heath D, Eng J, Horton KM, Scott WW, Fishman EK
  Emerg Radiol 2012 Mar 27
  

• "The issue of incidental findings in medical imaging will always be with us. Budoff et al. reminded us of the cost of pursuing unrequested information. Northam et al. found potential benefit. We may debate whether to perform an imaging examination. Once an examination is performed, the noblest approach is to view and evaluate all available data, to apply appropriate judgment, and to proceed in the best interest of the patient and society."

  Incidental Findings on Cardiac CT
  Colletti PM
  AJR 2008; 191:882-884

   

• "Volume analysis revealed that 35.5% of the total chest volume was displayed on dedicated coronary artery MDCT focused on the heart, whereas 70.3% of the chest was visible when MDCT raw data were reconstructed with the maximal field of view."

  Coronary artery imaging with contrast-enhanced MDCT: extracardiac findings
  Haller S et al
  AJR 2006 July; 187(1):105-110

   

• "Extracardiac findings were detected in 41 patients (24.7%). Findings were classified as minor (19.9%) or major (4.8%). Among the major findings, which had an immediate impact on patient management and treatment, were bronchial carcinoma and pulmonary emboli."

  Coronary artery imaging with contrast-enhanced MDCT: extracardiac findings
  Haller S et al
  AJR 2006 July; 187(1):105-110

• "In this study, 7.8% of patients undergoing screening EBCT examinations for coronary artery calcification were found to have important extracardiac pathology requiring additional work-up. Therefore, it is essential that a radiologist review the entire examination."

  Prevalence of Significant Noncardiac Findings on Electron-Beam Computed Tomography Coronary Artery Calcium Screening Examinations
  Horton KM, Post WS, Blumenthal RS, Fishman EK
  Circulation 2002;106:532-534

• Findings 
  103/1326 patients had extracardiac pathology requiring clinical or imaging follow-up
  - 53 patients with noncalcified nodules < 1 cm
  - 12 patients with noncalcified nodules > 1 cm- 24 patients with infiltrates
  - 7 patients with indeterminate liver lesions
  - 2 patients with sclerotic bone lesions
  - 2 patients with breast findings
  - 1 patient with polycystic liver disease
  - 1 patient with esophageal thickening
  - 1 patient with ascites

Prevalence of Significant Noncardiac Findings on Electron-Beam Computed Tomography Coronary Artery Calcium Screening Examinations
Horton KM, Post WS, Blumenthal RS, Fishman EK
Circulation 2002;106:532-534

• - 1326 consecutive patients underwent EBCT coronary artery scoring exams
  - 25 % former or current smokers
  - 2 Board -certified CT radiologists reviewed examinations on a workstation using mediastinal windows, lung windows and bone windows
  - Significant extra-cardiac abnormalities were noted
  - Circulation. 2002;106:532-534
  
  Prevalence of Significant Noncardiac Findings on Electron-Beam Computed Tomography Coronary Artery Calcium Screening Examinations
  Horton KM, Post WS, Blumenthal RS, Fishman EK
  Circulation 2002;106:532-534
  
• Prevalence of Significant Noncardiac Findings on Electron-Beam Computed Tomography Coronary Artery Calcium Screening Examinations

  Karen M. Horton, MD; Wendy S. Post, MD; Roger S. Blumenthal, MD; Elliot K. Fishman, MD

  Background— Screening electron-beam computed tomography (EBCT) examinations for the detection and quantification of coronary artery calcification are being performed throughout the country. In addition to information about the heart, great vessels, and coronary arteries, these examinations include portions of the lungs, bony thorax, and upper abdomen. The purpose of this study was to determine the prevalence of significant noncardiac findings in a series of patients undergoing coronary artery calcification screening studies with EBCT scanning.

  Methods and Results— Between January 1, 2001, and October 1, 2001, 1326 consecutive patients underwent coronary artery calcification screening with EBCT (3-mm-thick slices were obtained at 3-mm intervals). Two board-certified radiologists reviewed the examinations on a workstation using standard mediastinal windows, lung windows, and bone windows. Significant extracardiac abnormalities were noted. Of 1326 patients, 103 (7.8%) had significant extracardiac pathology requiring clinical or imaging follow-up. These included 53 patients with noncalcified lung nodules <1 cm, 12 patients with lung nodules 1 cm, 24 patients with infiltrates, 7 patients with indeterminate liver lesions, 2 patients with sclerotic bone lesions, 2 patients with breast abnormalities, 1 patient with polycystic liver disease, 1 patient with esophageal thickening, and 1 patient with ascites.

  Conclusions— In this study, 7.8% of patients undergoing screening EBCT examinations for coronary artery calcification were found to have important extracardiac pathology requiring additional work-up. Therefore, it is essential that a radiologist review the entire examination.

   

• “RESULTS: Of 966 patients (58 +/- 16 years of age, 55.4% men, >98% outpatients), 401 (41.5%) patients had noncardiac IF. A total of 12 (1.2%) patients had CS findings, and 68 (7.0%) patients had indeterminate findings. At follow-up (18.4 +/- 7.6 months), none of the indeterminate findings became CS. Although 3 patients with indeterminate findings were diagnosed with malignant lesions, they were unrelated to the IF. After adjusting for age, IF were not an independent predictor of noncardiac death.”

  Potential clinical and economic consequences of noncardiac incidental findings on cardiac computed tomography.
  Machaalany J et al.
  J Am Coll Cardiol 2009 Oct 13;54(16):1533-1541

   

• "RESULTS: Of 966 patients (58 +/- 16 years of age, 55.4% men, >98% outpatients), 401 (41.5%) patients had noncardiac IF. A total of 12 (1.2%) patients had CS findings, and 68 (7.0%) patients had indeterminate findings. At follow-up (18.4 +/- 7.6 months), none of the indeterminate findings became CS. Although 3 patients with indeterminate findings were diagnosed with malignant lesions, they were unrelated to the IF. After adjusting for age, IF were not an independent predictor of noncardiac death. Noncardiac death and cancer death in patients with and without IF were not statistically different. One patient suffered a major complication related to the investigation of an IF. The total direct cost associated with investigating IF was Canadian $57,596 (U.S. $83,035).”

  Potential clinical and economic consequences of noncardiac incidental findings on cardiac computed tomography.
  Machaalany J et al.
  J Am Coll Cardiol 2009 Oct 13;54(16):1533-1541

   

• CONCLUSIONS: Although noncardiac IF are common, clinically significant or indeterminate IF are less prevalent. Rates of death were similar in patients with and without IF, and IF was not an independent predictor of noncardiac death. The investigation of IF is not without cost or risk. Larger studies are required to assess the potential mortality benefit of identifying IF.”Potential clinical and economic consequences of noncardiac incidental findings on cardiac computed tomography.

  Machaalany J et al.
  J Am Coll Cardiol 2009
  Oct 13;54(16):1533-1541

• "MacHaalany et al. examined the costs of further diagnostic workup and followup in the cases of 966 patients who underwent cardiac CT. The total cost of further diagnostic steps was $83,035, $39,597 of which was attributed to care of a single patient with complicatios from alung biopsy. The average cost was $86 per patient and the median cost closer to $45; the authors cautioned that these figures were likely underestimates because costs incurred later were not included."
• What is needed in the best interest of the patient?
  - Review of the entire CT dataset by a qualified radiologist
  - Any findings that need immediate action or followup should be sent to the responsible referring physician
  - The radiologist may need to make certain that the recommendations are considered and followed up in a reasonable time frame
  - Lack of follow-up by ignoring the radiology report is not an accepted treatment arm
• "In the focused viewing scheme, 90.9% of the findings necessitating therapy, 64.1% necessitating workup, and 51.2% necessitating follow-up were missed. Use of the focused approach resulted in fewer false positive diagnosis but 5 malignant tumors of the breast, 88 lung infiltrates, 43 cases of lymphadenopathy, 2 cases of polycystic kidney, one breast abscess and one case of splenic flexure diverticulitis were missed."

• J Am Coll Cardiol, 2009; 54:1533-1541,

  Potential Clinical and Economic Consequences of Noncardiac Incidental Findings on Cardiac Computed Tomography

  Jimmy MacHaalany, MD, Yeung Yam, BSc, Terrence D. Ruddy, MD, Arun Abraham, MBBS, Li Chen, MSc, Rob S. Beanlands, MD, and Benjamin J.W. Chow, MD

  Objectives: We sought to determine the incidence, clinical significance, and potential financial impact of noncardiac incidental findings (IF) identified with cardiac computed tomography (CT).

  Background: Cardiac CT is gaining acceptance and may lead to the frequent discovery of extracardiac IF.

  Methods: Consecutive patients undergoing cardiac CT had noncardiac structures evaluated after full field of view (32 to 50 cm) reconstruction. IF were categorized as clinically significant (CS), indeterminate, or clinically insignificant. Patient follow-up was performed by telephone, and verified with hospital records and/or communication with physicians.

  Results: Of 966 patients (58 ± 16 years of age, 55.4% men, >98% outpatients), 401 (41.5%) patients had noncardiac IF. A total of 12 (1.2%) patients had CS findings, and 68 (7.0%) patients had indeterminate findings. At follow-up (18.4 ± 7.6 months), none of the indeterminate findings became CS. Although 3 patients with indeterminate findings were diagnosed with malignant lesions, they were unrelated to the IF. After adjusting for age, IF were not an independent predictor of noncardiac death. Noncardiac death and cancer death in patients with and without IF were not statistically different. One patient suffered a major complication related to the investigation of an IF. The total direct cost associated with investigating IF was Canadian $57,596 (U.S. $83,035).

  Conclusions: Although noncardiac IF are common, clinically significant or indeterminate IF are less prevalent. Rates of death were similar in patients with and without IF, and IF was not an independent predictor of noncardiac death. The investigation of IF is not without cost or risk. Larger studies are required to assess the potential mortality benefit of identifying IF.

• "Among 6920 patients, 1642 (23.7%) had one or more extracardiac findings for a total of 1,901 findings in the broad viewing scheme. Of the 6.920 patients, 16.2% had a finding necessitating therapy, workup or followup."

  Extracardiac Findings on Coronary CT Angiograms: Limited Versus Complete Image Review
  Johnson KM et al.
  AJR 2010; 195:143-148

• "Because minor findings far outnumber major findings, the ability to differentiate the two will be a crucial factor in determining the overall cost to benefit analysis"

  Extracardiac Findings on Coronary CT Angiograms: Limited Versus Complete Image Review
  Johnson KM et al.
  AJR 2010; 195:143-148

• "Almost one fourth of all patients who underwent diagnostic coronary CT angiography in this study had extracardiac findings. Several serious diagnoses were missed with the limited viewing approach, but use of the broad viewing approach led to more workup and follow-up imaging."

  Extracardiac Findings on Coronary CT Angiograms: Limited Versus Complete Image Review
  Johnson KM et al.
  AJR 2010; 195:143-148

• Large field of view vs Small field of view
  - Large field of view was 35-40 cm and review was of soft tissue and lung windows
  - Small field of view was 25 cm to include the heart and was reviewed at soft tissue windows only

• "A few cardiologists have suggested that the field of interpretation be restricted to avoid false positive diagnosis. Radiologists generally favor a comprehensive review to avoid false negative findings. The purpose of this study was to examine the tradeoff by comparing broad and focused approaches with viewing coronary CT angiograms."

  Extracardiac Findings on Coronary CT Angiograms: Limited Versus Complete Image Review
  Johnson KM et al.
  AJR 2010; 195:143-148

• "Primary interpretation of thoracic MDCT is less sensitive and more time consuming using 5 mm thick coronal reformations as compared with transverse images."
  
  Primary Interpretation of Thoracic MDCT Images Using Coronal Reformations
  Kwan SW et al.
  AJR 2005; 185:1500-1508
• "Images were then reconstructed with a high spatial frequency reconstruction kernel into contiguous 1.5 mm thick transverse sections. These sections were reformatted into 5 mm thick sections at an interval of 3.5 mm in the transverse and coronal planes. (4 slice MDCT scanner)â€"
  
  Primary Interpretation of Thoracic MDCT Images Using Coronal Reformations
  Kwan SW et al.
  AJR 2005; 185:1500-1508
• "Venous collateral pathways caused by the thoracic central venous obstruction from a complex network of venous drainage and can be simplified by application of 3-dimensional techniques that merge the tortuous vessels."
  
  Collateral Pathways in Thoracic Central Venous Obstruction: three Dimensional Display Using Direct Spiral Computed Tomography Venography
  Kim HC et al
  J Comput Assist Tomogr 2004; 28:24-33
• CT of the Thoracic Aorta: Causes of Study Failures
  
  - Injection technique faulty (too slow,contrast extravasation, etc.)
  - Poor scan timing (data acquisition to contrast delivery)
  - Ascending aorta
  - Patient motion during study
• CT of the Thoracic Aorta: Pitfalls
  
  - Artifacts off venous structures tend to be worse for left sided injections and create problems with the arch vessels as well as the ascending aorta
  - Possible solutions: saline chaser, caudal-cranial scanning
• CT of the Thoracic Aorta: Pitfalls
  
  - Aortic pulsation is an issue in the aortic root and ascending aorta and can result in false positive studies
  - Possible solutions: faster scanners (4-16-64), cardiac gating, partial scan data reconstruction (half scan reconstruction)
• MDCT vs. MR vs. TEE
  
  - Alternative diagnosis best defined on CT study
  - Pulmonary embolism
  - Mediastinal mass
  - Coronary artery occlusion
• "Given the advantage of volume rendering for representing the entire dataset and given the lower radiation dose and better 3D image quality of nongated acquisition, volume rendering performed on nongated MDCT is the method of choice for 3D visualization of the bronchial tree."
  
  Effects of ECG Gating and Postprocessing techniques on 3D MDCT of the Bronchial Tree
  Schertler T et al.
  AJR 2004;183:83-89
• "Multidetector CT virtual bronchoscopy is a reliable noninvasive method that allows accurate grading of tracheobronchial stenosis. However, it should be combined with the interpretation of axial CT images and multiplanar reformatted images for evaluation of surrounding structures and optimal spatial orientation."
  
  Multidetector CT Virtual Bronchoscopy to Grade Tracheobronchial Stenosis
  Hoppe H
  AJR 2002;178:1195-2000