Page 90 - JSOM Summer 2018

a 2- to 3-month delay in surgery and further deconditioning of diagnosis using MRI results was correct 72% of the time, com-
the Operator, which would require even more time to recover. pared with 64% for ultrasound. A similar study looked at the
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Also, there were instances where rest, not PT, is indicated, to accuracy rate of MRI and physical examination in detecting
decrease the chance of worsening an injury. knee injury compared with definitive arthroscopic findings.
Detection via MRI of knee injury occurred with an accuracy
Of the total MRIs performed, injuries attributed to various rate of 84.21% compared with 63.14% for physical examina-
MOIs except overuse (45.7%) and military training (31.4%) tion within the respective study group. Hodgson et al. noted
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accounted for the majority (77.1%). The most common im- that MRI is valuable for assessing tendon and ligament disease
aging sites were the knee (10% to 28.6%) and shoulder (9% throughout the body and has good sensitivity and specificity
to 25.7%). compared with the gold standard of open orthopedic surgery.
As noted, the shoulder was the second most commonly im-
The most prevalent diagnoses were ligament and tendon in- aged joint; MRI has remarkable sensitivity (92%) and spec-
juries, which accounted for 51.4% (n = 18) of the total MRIs ificity (93%) for full-thickness tears of the rotator cuff when
conducted and which would have not been diagnosed if im- validated by open surgery, as well as diagnosing tears of the
aged via conventional radiography. Three MRIs revealed three Achilles, posterior tibial, and biceps tendons; and the lateral
bone contusions, which, in the judgment of the radiologist, epicondyle. 9
would not have been likely to show on radiograph. Only two
documented cases (5.7%) showed pure bone abnormalities Although MRIs are better suited to soft-tissue injuries, radio-
(distal clavicular osteolysis) that potentially would have ap- graphs have been used as the primary diagnostic tool for mus-
peared on conventional radiographs. culoskeletal injuries since their invention in 1895 by Wilhelm
Roentgen. As noted by Sir Joseph Lister in 1896, “If the skin is
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Of the total number of MRIs conducted, 11 images (31.4%) long exposed to [the X-rays’] action, it becomes very much ir-
resulted in the need for surgical intervention to correct the un- ritated, affected with a sort of aggravated sun burning.” Now,
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derlying injury for eight Operators (44.4% of those imaged; nearly two-thirds of the 5 billion diagnostic imaging cases
17.7% total in the squadron). If the lumbar spine is excluded, yearly use IR technologies. However, these cases should strive
for which MRIs were conducted due to low back pain without to keep exposure levels as low as reasonably achievable (known
neurologic symptoms and for which no surgical intervention as the ALARA [As Low As Reasonably Achievable] principle).
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was required, this would result in 53.3% of the Operators im- From 1956 to the present, epidemiologic studies have linked di-
aged requiring surgical intervention. With such high numbers agnostic X-rays with an increase in cancer rates among patients
of those imaged requiring surgical intervention, it would sub- who had undergone imaging. Like other issues in medicine,
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sequently follow that rapid examination by MRI would be the X-rays should be used as indicated, and it should be taken into
most effective diagnostic tool to return Operators to full-duty account that the benefits outweigh the risks. Since X-rays are
status in a timely manner. not used to aid diagnosis of ligament, tendon, and cartilage
injuries in patients with this injury pattern and because there is
This high number of positive studies, as well as the referral a risk in exposing patients of this age to X-rays, X-rays should
rate for surgery, speaks to the selectivity for imaging these Op- be avoided in this setting and become a thing of the past.
erators. This is a function of both the Operators not present-
ing without real pain or dysfunction and the threshold held by In his address to the Ulster County Medical Society in 2012,
the medical team about who to actually image. Dr Spence, in consideration of wider transition to MRI, said,
“With the advances in imaging, and CT in particular, and the
Many articles have been published showing the effectiveness exponential increase in use, we must remain conscious of the
of MRI as a diagnostic tool. Several sources compare radio- possible long-term adverse effects such as cancer. . . [with] bet-
logical findings using both MRI and other imaging modalities ter information for patients and clinicians.” 3
and conclude that MRI is more beneficial. Even for bone pa-
thology in arthritis, MRI shows a clear advantage for identify- The increase in cancer rates can be attributed to the ionizing
ing the stages and types of osteoarthritis compared with plane radiation of X-rays having the ability to damage DNA, which
radiography. Plane radiographs are effective in helping iden- occurs via two mechanisms: (1) direct hit of a target where the
tify the erosive effects that appear late in joint osteoarthritis; nuclear DNA is the major target molecule and (2) nontargeted
however, MRI can show the early inflammatory signs of this effects or indirect actions of radiation. Radiation injury can
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disease, which occur much earlier. From a qualitative perspec- result in early (e.g., burns, local necrosis, nausea and vomit-
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tive, MRI distinctly displays evidence of traumatic orthopedic ing, cardiac pathologies, brain edema, and, in extreme cases,
injury when compared with CT, the fastest growing source of death) and late effects (e.g., cancer, genetic defects). Such
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medical IR. One study showed posterior wall lengths assessed early effects would result from overdoses of acute exposures.
by CT in multiple dislocated and intact acetabula were lower Cancerous and hereditary effects are not identified in the short
than all measurements taken by MRI. This indicated the se- term after the imaging; rather, they are due to the genetic mu-
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verity of injury to the joint was more clearly shown by MRI. tations, which are extremely complex and take decades to
In addition, MRI results were able to show soft-tissue injury manifest. IR can break the DNA directly and can create free
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not evident by CT scan. 5 radicals, which can contribute to an increase of and prolong
DNA damage. Thus, imaging examinations that do not re-
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Conventional radiography does not image the soft tissues. quire IR exposure and are as good as or better than IR exam-
MRI has become the diagnostic tool of choice when identify- inations should be preferred, especially for younger patients. 10
ing soft-tissue injury. In a study comparing the radiological
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findings of MRI and other imaging modalities, notably ultra- Finally, 68% of MRIs, excluding lumbosacral MRIs, were posi-
sound, compared with clinical findings of acute groin injury, tive, indicating that the studies were not frivolously performed.

88 | JSOM Volume 18, Edition 2/Summer 2018