Advertisement

The Scout Film

  • Mary M. Salvatore
  • Ronaldo Collo Go
  • Monica A. Pernia M.
Chapter

Abstract

Six to eleven percent of important findings are excluded in the CT FOV, and 2% of these can be seen on the scout film, thus highlighting its importance [Johnson et al., AJR Am J Roentgenol. 202:1256–1263, 2014]. Leonard Berlin’s article, reviewing the CT scout view: medicolegal and ethical considerations, admits that the scout film is unlikely to demonstrate a significant abnormality; however, because 85 million CT scans are performed a year, the scout film could help to identify nearly 2.5 million abnormalities not included on the CT scan FOV [Berlin, AJR Am J Roentgenol. 202:1264–1266, 2014]. The value of the scout film cannot be overstated; it provides an overview of the patient’s condition. Review of the scout film helps you to identify lines and tubes that you may otherwise have ignored. Orthopedic hardware assessment is facilitated on the scout film as is foreign body recognition. Scoliosis can be measured on the scout film [Ho et al., Spine (Phila PA 1976). 17:771–774, 1992]. Diaphragmatic elevation can be quantified on this view.

Keywords

Chest tube Central line Endotracheal tube Feeding tube Sternal wires 

Six to eleven percent of important findings are excluded in the CT FOV, and 2% of these can be seen on the scout film, thus highlighting its importance [1]. Leonard Berlin’s article, reviewing the CT scout view: medicolegal and ethical considerations, admits that the scout film is unlikely to demonstrate a significant abnormality; however, because 85 million CT scans are performed a year, the scout film could help to identify nearly 2.5 million abnormalities not included on the CT scan FOV [2]. The value of the scout film cannot be overstated; it provides an overview of the patient’s condition. Review of the scout film helps you to identify lines and tubes that you may otherwise have ignored. Orthopedic hardware assessment is facilitated on the scout film as is foreign body recognition. Scoliosis can be measured on the scout film [3]. Diaphragmatic elevation can be quantified on this view. Let’s review some examples.

2.1 Lines and Tubes Visible on the Scout Film

Endotracheal tubes are ideally positioned 2.5 cm above the carina. This is difficult because when we look at the endotracheal tube, we do not know the position of the head which may cause the endotracheal tube position to change. There is an expression, “as goes the nose, so goes the hose.” When the neck is flexed, the ET tube moves inferiorly, and when the neck is extended, the tube moves superiorly [4]. When judging the location of the tube, it should not project above the clavicles or at the level of the carina (Fig. 2.1).
Fig. 2.1

Endotracheal tube in correct position on scout film

Feeding tube needs to be positioned with its tip below the diaphragm to assure that it is not in the lung, ideally, 10 cm beyond the gastroesophageal junction [5]. The distal tip of the tube does not need to be included on the film to say that it is well-positioned to use (Fig. 2.2). If a feeding tube does not extend below the diaphragm, one cannot be sure if it is in the esophagus and it needs to be repositioned.
Fig. 2.2

Feeding tube in correct position on scout film

Central lines are either subclavian or internal jugular lines. The important thing to remember is that all right-sided catheters should stay on the right and left-sided catheters should cross to the right. If the catheter does not, it may be located in an artery, and a blood gas should be obtained from catheter blood to ensure location in a vein and not an artery. Ideally most catheters should terminate at SVC/right atrial junction [6] unless they are being used for high flow and then they may be situated in the right atrium (Figs. 2.3 and 2.4).
Fig. 2.3

Right IJ catheter with tip in SVC/right atrial junction

Fig. 2.4

Left internal jugular catheter with tip in right atrium. Mitral valve prosthesis and partially imaged IVC filter

Chest tubes have a discontinuous line that identifies the last side hole. This area of discontinuity must project over the hemithorax, or there will be an air leak. Typically the tip of a chest tube is placed superiorly in a pneumothorax in an upright patient and anteriorly in a supine patient. A chest tube is ideally placed inferiorly to treat a pleural effusion in an upright patient and posteriorly in a supine patient [7] (Fig. 2.5).
Fig. 2.5

Right chest tube for pleural effusion

Sternotomy wires can be circular or in a figure eight configuration depending on the surgeon’s preference. Discontinuous wires suggest the possibility of sternal infection and should be noted [8] (Fig. 2.6).
Fig. 2.6

Dehiscent sternal wires in patient with sternal infection

Pacemakers are common and can stop working if wires are fractured which happens when people “twiddle” with the device under their skin. One can suspect “Twiddler’s syndrome” if the wires appear stretched and redundant [9] (Fig. 2.7).
Fig. 2.7

Intact left-sided pacemaker

2.2 Orthopedic Hardware Assessment

Shoulder prosthesis can be readily identified on the scout film. Evaluation of prosthesis on axial images is limited by beam-hardening artifact [10] (Fig. 2.8).
Fig. 2.8

Right shoulder prosthesis

Spinal fixation devices are frequent, and alignment can often be better judged on the scout film than on the axial images because of beam-hardening artifacts (Fig. 2.9).
Fig. 2.9

Cervical spine fixation

Pectus correction apparatus is used when patients have a Haller index of greater than 2.5. Haller index is a measure of transverse diameter over narrowest AP diameter. The larger the number, the greater the deformity [11] (Fig. 2.10).
Fig. 2.10

Pectus correction device

2.3 Foreign Body

Retained catheter fragments can be difficult to appreciate on the axial images especially if contrast is used, so the scout film allows an opportunity to identify the object. Shrapnel can occur anywhere in the chest, and recognizing the appearance of shrapnel is important so as not to confuse it for other diseases (Fig. 2.11).
Fig. 2.11

Shrapnel

2.4 Spine Deformity

Scoliosis is quantified on X-ray by measuring the Cobb angle at the location of most severe curvature [12] (Fig. 2.12).
Fig. 2.12

Scoliosis

Kyphosis is common with aging. It is often accelerated when a patient develops a wedge-shaped anterior compression fracture [13]. Compression fractures are often treated with vertebroplasty in order to regain the normal alignment of the spine (Fig. 2.13).
Fig. 2.13

Vertebroplasty for treatment of compression fracture

2.5 Diaphragm

Apparent elevation of the diaphragm can occur when there is a tear in the diagram and the abdominal organs herniate through the tear (Fig. 2.14). Injuries to the right hemidiaphragm are three times more common than injuries to the left hemidiaphragm following blunt injury. Injuries to the left hemidiaphragm are more frequently missed than injuries to the right hemidiaphragm. The “collar sign” is a waist-like constriction of the herniating hollow viscous at the site of the diaphragmatic tear [14].
Fig. 2.14

Herniated bowel above the diaphragm

Phrenic nerve paralysis can happen because of mediastinal cancer invading the nerve or secondary to surgery where the nerve is injured. Preoperative chest X-rays where the diaphragm is normal followed by postoperative chest X-ray where it is elevated will suggest the later diagnosis [15] (Fig. 2.15).
Fig. 2.15

Phrenic nerve paralysis

Eventration or mammillation of the hemidiaphragm is common and caused by focal weakness allowing abdominal contents to bulge superiorly [16] (Fig. 2.16).
Fig. 2.16

Diaphragmatic eventration

References

  1. 1.
    Johnson PT, Scott WW, Gayler BW, Lewin JS, Fishman EK. The CT scout view: does it need to be routinely reviewed as part of the CT interpretation? AJR Am J Roentgenol. 2014;202:1256–63.CrossRefPubMedGoogle Scholar
  2. 2.
    Berlin L. Reviewing the CT scout view: medicolegal and ethical considerations. AJR Am J Roentgenol. 2014;202(6):1264–6.CrossRefPubMedGoogle Scholar
  3. 3.
    Ho EK, Upadhyay SS, Ferris L, Chan FL, Bacon-Shone J, Hsu LC, Leong JC. A comparative study of computed tomographic and plain radiographic methods to measure vertebral rotation in adolescent idiopathic scoliosis. Spine (Phila PA 1976). 1992;17(7):771–4.CrossRefGoogle Scholar
  4. 4.
    Goodman LR, Conrardy PA, Laing F, Singer MM. Radiographic evaluation of endotracheal tube position. AJR Am J Roentgenol. 1976;127(3):433–4.CrossRefPubMedGoogle Scholar
  5. 5.
    Pillai JB, Vegas A, Brister S. Thoracic complications of nasogastric tube: review of safe practice. Interact Cardiovasc Thorac Surg. 2005;4(5):429–33.CrossRefPubMedGoogle Scholar
  6. 6.
    Funaki B. Central venous access: a primer for the diagnostic radiologist. AJR Am J Roentgenol. 2002;179(2):309–18.CrossRefPubMedGoogle Scholar
  7. 7.
    Godoy MC, Leitman BS, de Groot PM, Vlahos I, Naidich DP. Chest radiography in the ICU: part 1, evaluation of airway, enteric, and pleural tubes. AJR Am J Roentgenol. 2012;198(3):563–71.CrossRefPubMedGoogle Scholar
  8. 8.
    Schimmer C, Reents W, Elert O. Primary closure of median sternotomy: a survey of all German surgical heart centers and a review of the literature concerning sternal closure technique. Thorac Cardiovasc Surg. 2006;54(6):408–13.CrossRefPubMedGoogle Scholar
  9. 9.
    Sharifi M, Inbar S, Neckels B, Shook H. Twiddling to the extreme: development of twiddler syndrome in an implanted cardioverter-defibrillator. J Invasive Cardiol. 2005;17(3):195–6.PubMedGoogle Scholar
  10. 10.
    Yian EH, Werner CM, Nyffeler RW, Pfirrmann CW, Ramappa A, Sukthankar A, Gerber C. Radiographic and computed tomography analysis of cemented pegged polyethylene glenoid components in total shoulder replacement. J Bone Joint Surg Am. 2005;87(9):1928–36.CrossRefPubMedGoogle Scholar
  11. 11.
    Rao AG. Haller index in patients with pectus excavatum. AJR Am J Roentgenol. 2012;199(5):W665. author reply W666.CrossRefPubMedGoogle Scholar
  12. 12.
    Langensiepen S, Semler O, Sobottke R, Fricke O, Franklin J, Schönau E, Eysel P. Measuring procedures to determine the Cobb angle in idiopathic scoliosis: a systematic review. Eur Spine J. 2013;22(11):2360–71.CrossRefPubMedPubMedCentralGoogle Scholar
  13. 13.
    Katzman WB, Wanek L, Shepherd JA, Sellmeyer DE. Age-related hyperkyphosis: its causes, consequences, and management. J Orthop Sports Phys Ther. 2010;40(6):352–60.CrossRefPubMedPubMedCentralGoogle Scholar
  14. 14.
    Iochum S, Ludig T, Walter F, Sebbag H, Grosdidier G, Blum AG. Imaging of diaphragmatic injury: a diagnostic challenge. Radiographics. 2002;22:S103–16.CrossRefPubMedGoogle Scholar
  15. 15.
    Gaissert H, Wilcox SR. Diaphragmatic dysfunction after thoracic operations. Thorac Cardiovasc Surg. 2016;64(8):621–30.CrossRefPubMedGoogle Scholar
  16. 16.
    Verhey PT, Gosselin MV, Primack SL, Kraemer AC. Differentiating diaphragmatic paralysis and eventration. Acad Radiol. 2007;14(4):420–5.CrossRefPubMedGoogle Scholar

Copyright information

© Springer International Publishing AG, part of Springer Nature 2018

Authors and Affiliations

  • Mary M. Salvatore
    • 1
  • Ronaldo Collo Go
    • 2
  • Monica A. Pernia M.
    • 3
  1. 1.RadiologyIcahn School of Medicine at Mount SinaiNew YorkUSA
  2. 2.Division of Pulmonary, Critical Care, and Sleep MedicineCrystal Run Health CareMiddletownUSA
  3. 3.Internal MedicineNew York Medical College - Metropolitan Hospital ProgramNew YorkUSA

Personalised recommendations