When combined with
bone scan and white blood cell imaging agents, single photon
emission computed tomography and computed tomography displays a clear and
accurate screening of possible infection of the foot for
diabetes patients, according to a study conducted by Sherif
Heiba, MD, associate professor of radiology at Mount Sinai School of Medicine,
and colleagues. Heiba presented his findings at the Society of Nuclear
Medicine’s Annual Meeting in San Antonio, Texas.
According to Heiba, the methodology is a combination of well-known
technology and new technology. White blood cell scanning is not a new method
for looking at an infection.
“The new application is the fact that we are combining these two
methods with a new technique called the single photon emission computed
tomography and computed tomography (SPECT/CT),” Heiba said. “The
combination of the two imaging agents, along with SPECT/CT, has produced
successful imaging.”
Heiba was particularly interested in whether this new protocol would
salvage the lower extremity limb of an infected patient.
“The underlying pathologies and the wide range of possible problems
with the diabetic foot have made diagnosis a challenge over the years,”
Heiba told O&P Business News. “Because we can now
distinguish between the different pathologies in the foot, we can define what
infection is presented. The surgeon would have more information and anatomic
guidelines to manage the patient.”
Combined molecular imaging agents allow for a more accurate and
clinically effective way to detect the presence of foot infection, as well as
the location of any soft tissue or bone infections on the diabetic foot, Heiba
said.
According to the American Diabetes Association, 25.8 million children
and adults in the US have diabetes. More than 60% of non-traumatic lower limb
amputations occur in people with diabetes. By having a more accurate image to
detect and localize possible infection, physicians are more apt to manage the
patient with conservative treatment options, such as debridement or limb
salvage.
“The study showed fewer amputations among the participants because
physicians are not only able to make an accurate diagnosis but they are able to
localize it as well,” Heiba said. “They may be more comfortable
conducting a minor procedure rather than major amputation of the entire
extremity. Major amputation will affect the patient’s survival and quality
of life.”
In a 5-year study, 191 participants have underwent molecular imaging
with bone and white blood cell scan agents with SPECT/CT. A total of 227 scans
were performed. Physicians managed their patients guided by information from
207 of the 227 total scans (94%). The results of the scans indicated 84 cases
of bone infection (osteomyelitis) and 93 softtissue infections; 25 patients had
a combination of both infections and 25 patients were diagnosed with other
pathologies.
“What we concluded from this study is that the dual isotope
SPECT/CT imaging is crucial because it accurately makes the diagnosis and can
distinguish between softtissue and bone infections,” Heiba said. “It
can give the physician an evaluation of where exactly the infection is
presented and the extent of the involvement in the soft tissue or the
bone.”
Of the 207 clinical decisions founded on information from the dual
isotope SPECT/CT, 150 decisions, or 72%, leaned toward conservative management,
such as antibiotics or soft-tissue debridement of the infection around the
diabetic foot. Forty-nine scans (24%) led to partial bony resection or toe
amputations. According to Heiba, partial toe amputations still preserve the
entire foot. Only eight scans led to major amputations, which Heiba defined as
an above-knee or below-knee amputation.
“This has been successful for almost every patient suspected of
infection,” Heiba concluded. “In our medical center, patients undergo
this procedure routinely rather than wasting time with other less accurate
methods.” — by Anthony Calabro
For more information:
American Diabetes Association. Diabetes Statistics. Available at:
http://www.diabetes.org/diabetes-basics/diabetes
statistics/?utm_source=WWW&utm_medium=DropDownDB&utm_content=Statistics&utm_campaign=CON.
Accessed: Aug. 4, 2011.
