Editing Medical ultrasound (section)

==Attributes==
As with all imaging modalities, ultrasonography has positive and negative attributes.

===Strengths===
* [[Muscle]], [[soft tissue]], and bone surfaces are imaged very well including the delineation of interfaces between solid and fluid-filled spaces.
* "Live" images can be dynamically selected, permitting diagnosis and documentation often rapidly. Live images also permit ultrasound-guided biopsies or injections, which can be cumbersome with other imaging modalities.
* Organ structure can be demonstrated.
* There are no known long-term side effects when used according to guidelines, and discomfort is minimal.
* Ability to image local variations in the mechanical properties of soft tissue.<ref>{{cite journal | author = Nightingale KR, Soo MS, Nightingale R, Trahey GE | year = 2002 | title = Acoustic radiation force impulse imaging: in vivo demonstration of clinical feasibility | journal = Ultrasound in Medicine & Biology | volume = 28 | issue = 2| pages = 227–235 | doi = 10.1016/s0301-5629(01)00499-9 | pmid = 11937286 }}</ref>
* Equipment is widely available and comparatively flexible.
* Small, easily carried scanners are available which permit bedside examinations.
* Transducers have become relatively inexpensive compared to other modes of investigation, such as [[CT scan|computed X-ray tomography]], [[Dual energy X-ray absorptiometry|DEXA]] or [[magnetic resonance imaging]].
* [[Image resolution#Spatial resolution|Spatial resolution]] is better in high frequency ultrasound transducers than most other imaging modalities.
* Use of an [[ultrasound research interface]] can offer a relatively inexpensive, real-time, and flexible method for capturing data required for specific research purposes of tissue characterization and development of new image processing techniques.

=== Weaknesses ===
[[File:Aorta duplication artifact 131206105958250c.jpg|thumb|Double aorta artifact in sonography due to difference in velocity of sound waves in muscle and fat]]
* Sonographic devices have trouble penetrating [[bone]]. For example, sonography of the adult brain is currently very limited.
* Sonography performs very poorly when there is gas between the transducer and the organ of interest, due to the extreme differences in [[acoustic impedance]]. For example, overlying gas in the gastrointestinal tract often makes ultrasound scanning of the [[pancreas]] difficult. Lung imaging however can be useful in demarcating pleural effusions, detecting [[heart failure]] and pneumonia.<ref>{{cite journal |last1=Llamas-Álvarez |first1=Ana M. |last2=Tenza-Lozano |first2=Eva M. |last3=Latour-Pérez |first3=Jaime |title=Accuracy of Lung Ultrasonography in the Diagnosis of Pneumonia in Adults |journal=Chest |date=February 2017 |volume=151 |issue=2 |pages=374–382 |doi=10.1016/j.chest.2016.10.039 |pmid=27818332 |s2cid=24399240 }}</ref>
* Even in the absence of bone or air, the depth penetration of ultrasound may be limited depending on the frequency of imaging. Consequently, there might be difficulties imaging structures deep in the body, especially in obese patients.
* Image quality and accuracy of diagnosis is limited with obese patients and overlying subcutaneous fat attenuates the sound beam. A lower frequency transducer is required with subsequent lower resolution.
* The method is operator-dependent. Skill and experience is needed to acquire good-quality images and make accurate diagnoses.
* There is no scout image as there is with CT and MRI. Once an image has been acquired there is no exact way to tell which part of the body was imaged.
* 80% of sonographers experience Repetitive Strain Injuries (RSI) or so-called Work-Related Musculoskeletal Disorders (WMSD) because of bad ergonomic positions.