Diffrentiate between PA and AP chest x- ray

Posted on Updated on

Normally PA view is preferred. The clavicles won’t project too high into the  apices or thrown above the apices. The heart won’t be magnified over the  mediastinum. The ribs will not appear distorted or unnaturally horizontal like  in lordotic chests. However pediatric chests normally employ AP recumbant or  upright views because the infants or toddlers can take full inspirations and  their body won’t be so thick that anatomy will matter much in PA vs AP views.

BY EMAIL:

“Most differences in appearance are due to magnification differences and to changes in the alignment of the x-ray beam to the patient (mainly involving the “divergence of the beam” from its nearly “point source” to its pyramidal shape as it leaves the tube).

We usually like to perform chest x-rays with the patient in the erect or upright PA or (postero)anterior position–i.e., with the anterior surface nearest the film or image-receptor–and with the distance from the source, target or focal spot (on the anode) of the tube to the image receptor, that distance being called the “SID” (or FFD, AFD, TFD), preferably 72″ or so.

1. The erect position allows the diaphragm to descend more during (usually) suspended full inspiration, allowing the lungs to expand more, and the organs–including the heart–to be less “distorted” and “compressed” (as well as allowing gravity to help move abdominal organs downward and “out of the way”).

2. When the patient is facing the film, the heart–which is more anteriorly situated in the thorax–is nearer the image receptor, resulting in less magnification, and thus more “sharpness”, or recorded detail, than would be present were the patient in the AP position. Also, if done AP, patients tend to lean backward, causing what is called in radiology a “lordotic” appearance to the chest, with the clavicles appearing higher than normal, relative to the rib cage, and with the ribs themselves taking on a more “horizontal” appearance.

3. With a large SID, there is also less magnification (and more sharpness) of the image, compared to what would be obtained at lesser distances. In addition (or, related to this), the more central portion of the useful beam we will utilize at greater SID’s will exhibit less “divergence”
than one would note if using short SID’s (as we’d have to use more of the outer edges of the beam in order to cover the image receptor); this should mean, for the larger SID’s, there will also be less “shape distortion” than one would find with smaller distances.

The posterior ribs will appear more magnified, and the anterior less so, on a PA projection than on an AP. And the diaphragm (because the higher anterior portions are closer to the film when the patient is PA) may also appear differently than it will on an AP.

So, particularly if the patient is done not only AP but supine (lying on his back), and at a shorter SID (say, 40″ or so), the resulting image may be greatly different from that obtained with the usual PA erect CXR done at 72″:

* The chest (ribs and lungs) may appear broader and shallower
* The heart will appear larger and “flatter” (more distorted)
* The clavicles may appear higher than normally seen on a PA, and the sternoclavicular joints may appear “farther apart”
* The anterior ribs may look “wider” (and farther from the midline, due to the DOB, particularly with shorter SID’s), while the posterior ribs may look narrower and “sharper” (because they’re closer to the film), and all ribs may appear to be more horizontally directed (especially if the patient is leaning backward some)
* One might note fewer ribs visible above the diaphragm, partly due to the magnification differences and partly–for the supine patient–due to the increased difficulty in taking in a deep breath and to the “loss” of the benefits of gravity in displacing the abdominal contents downward
* In addition, when done AP, patients may tend to depress rather than to elevate the chin, which could cause it to be superimposed over the apices of the lungs (and which also may make it harder for the patient to take in a deep breath)
* The scapulae are less likely to be drawn laterally (out of the lung fields) when the patient is AP than when PA, and will also be closer to the film, so their edges will be even sharper than is normally seen”

Advertisements

24 thoughts on “Diffrentiate between PA and AP chest x- ray

    vijay nand chaudhary said:
    April 4, 2015 at 3:43 am

    I like reading the books
    so sent me a knowledge book but medical line

    Kandle Video Analysis Software | Game said:
    January 17, 2015 at 8:57 pm

    […] Diffrentiate between PA and AP chest x- ray | Medical … – 23/11/2011 · Software Provides Data Analytics to Teleradiology Program By Medimaging International staff writers Posted on 23 Nov 2011 A data analytics system …… […]

    snow plowing Valparaiso, Indiana said:
    August 14, 2014 at 6:22 am

    Major thanks for the article.Thanks Again. Fantastic.
    snow plowing Valparaiso, Indiana

    snow plowing Valparaiso, In said:
    August 12, 2014 at 7:57 am

    A round of applause for your article post.Much thanks again. Cool.
    snow plowing Valparaiso, Indiana

      Bunga said:
      November 30, 2016 at 9:21 am

      Hi! I would like to know why we use SID 40″ for AP supine chest as we known that shorter SID will increase the magnification of heart. Tq

    wakeupnow said:
    August 11, 2014 at 2:32 pm

    A big thank you for your article post.Much thanks again. Want more.
    wake up now review

    customerss said:
    August 11, 2014 at 8:54 am

    Thanks for sharing, this is a fantastic post.Really thank you! Awesome.
    marketing strategy

    computer repair lexington sc said:
    August 9, 2014 at 6:43 am

    I cannot thank you enough for the article.Much thanks again. Want more.
    computer store in columbia sc

    tenancy cleaning clapham said:
    August 8, 2014 at 5:05 am

    wow, awesome blog article. Cool.
    clapham cleaning

    detoxification said:
    August 7, 2014 at 12:36 pm

    I really like and appreciate your article post.Really thank you! Keep writing.
    detox foot pads

    wireless presentation system said:
    August 7, 2014 at 6:19 am

    I think this is a real great post.Really thank you! Fantastic.
    wireless interactive presentation system

    how do i get rid of spots said:
    August 6, 2014 at 3:17 am

    A round of applause for your blog post.Really thank you! Really Cool.
    how do i get rid of spots

    cpa marketing said:
    August 5, 2014 at 5:48 am

    Im obliged for the article.Really thank you! Awesome.
    more money with cpa

    Chinese tuition said:
    August 4, 2014 at 1:39 pm

    I value the blog article.Really thank you! Great.
    improve chinese subjects

    personal budget software said:
    August 4, 2014 at 2:26 am

    Very informative blog article.Really thank you!
    personal budget software

    orologi replica said:
    August 1, 2014 at 10:18 am

    Major thankies for the article post.Really looking forward to read more. Will read on…
    orologi replica

    best 10 inch tablet said:
    July 30, 2014 at 10:06 pm

    This is one awesome blog post. Really Cool.
    best 10 inch tablet

    bogwcrn said:
    July 27, 2014 at 7:07 pm

    zMGU0r aoazbxvvubxl, [url=http://ozqtxunixzyq.com/]ozqtxunixzyq[/url], [link=http://fzwdsonocemi.com/]fzwdsonocemi[/link], http://jjwfvdyxycbo.com/

    WW85 said:
    May 14, 2014 at 12:39 am

    So sorry you are going to skip the workshop!

    harmonioustew said:
    February 17, 2014 at 8:28 pm

    now you’re speaking my language.

    Lesley Zizzo said:
    February 11, 2014 at 10:27 am

    Robert, they vary. It’s up on the authors. Many in the letters coming up are handwritten, or hand-notated, it’s about half and half. Though most on the first letters were typed. The fourth letter was a comic.

    Creative said:
    December 15, 2011 at 6:24 pm

    I want to transfer to a college that focuses on English and have a good Creative Writing program. I want to major in creative writing but don’t know what college to transfer to..

    Blaxabacy said:
    December 11, 2011 at 3:43 am

    Flight reader could be the company name that each from on the number of or possibly even longer sites on the net may possibly go by. You probably know a lot of flight protection is actually, although in the event you don’t let’s explain this blend of the two of these phrases together with get them inside wording. A journey scanner is solely an element by the use of you access travel arrangements with several, typically 100s, involving aircraft, fit access and costs, for virtually any choice. The following will be your meaning associated with a specialized airline ticket scanner blog. Nonetheless, wish site is not really a devoted airline ticket scanner, inside extensive feeling with the phrase, the application doesn’t means that the application can’t be described as a flight reader.

    Teleradiology said:
    November 23, 2011 at 7:01 pm

    Software Provides Data Analytics to Teleradiology Program
    By Medimaging International staff writers
    Posted on 23 Nov 2011
    A data analytics system provides users the ability to correlate data across healthcare information technology (IT) applications and act upon the analytics, which is critical to maintaining quality of care provided by the healthcare community to its growing customer base.

    The US Veterans Health Administration’s (Washington DC, USA) National Teleradiology Program (VA-NTP) recently awarded a multiyear contract for comprehensive data analysis and reporting platform to Health Level, Inc. (Mountain View, CA, USA). The VA-NTP serves more than 30 VA Medical Centers across the United States and has a waiting list for its effective radiology diagnostic services.

    With this new capability, VA-NTP staff and management can direct questions and visualize correlations between diverse parameters such as staffing levels, case mix, critical cases, revenue, and seasonal patterns. The project scope includes clinical, operational, and financial data for all staffing locations and customer sites across multiple time zones. Service performance reports for VA Medical Centers as well as staff metrics can be distributed confidentially and securely. This capability simplifies reporting, improves transparency, and continually ensures collaborative decisions between VA-NTP customers and staff.

    “This selection by VA-NTP demonstrates the commitment to improve efficiency, outcomes, and financial performance through fact-based analytics to drive informed decisions,” according to Parag Paranjpe, chief executive officer of Health Level, Inc. “As the data set grows, VA-NTP will be able to mine the data for continuous quality improvement. This data set will also be available to all VA-NTP customers across the system for real-time analytics integrated with large volume of historical insight.”

    VHA National Teleradiology Program (NTP) is a US clinical entity, established by the recommendation of the Teleradiology Workgroup and the chief consultant for diagnostic services to address the radiologist staffing shortage across the VA system, and to utilize the existing radiology workforce. The program is hosted by the VA Palo Alto HCS (PAHCS; CA, USA) and is currently headquartered in Menlo Park (CA, USA) with reading centers in three time zones.

    Health Level is the industry’s first integrated real-time and multiyear correlation platform for clinical, operational, and financial data. Focusing on data analytics and reporting for hospitals and healthcare systems, Health Level’s goal to empower staff through user-friendly data analysis to improve transparency and efficiency.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s