Effect of Carpal Tunnel Syndrome on the Ulnar Nerve at the Wrist
Sonographic and Electrophysiologic Studies
Objectives—The aim of this study was to compare the
ulnar nerve at the wrist by sonographicand electrophysiologic studies between
patients with carpal tunnel syndrome and control participants and to verify the
effect of carpal tunnel syndrome of the ulnar nerve at the wrist.
Methods—Forty-two hands of patients with carpal tunnel syndrome and 37
hands of control participants were examined. Electrophysiologic studies of the
ulnar nerve were done in all participants. The cross-sectional areas of the
median and ulnar nerves at the wrist were evaluated by sonography. Fifteen
hands of patients with carpal tunnel syndrome who underwent carpal tunnel
release were also evaluated by sonography after the operation.
Results—The ulnar nerve cross-sectional area of the patients with carpal
tunnel syndrome (mean ± SD, 5.16 ± 1.04 mm2)
was significantly larger than that of the controls (3.56 ± 0.52 mm2; P < .0001). After release of the transverse
carpal ligament, the cross-sectional area of the ulnar nerve was significantly
smaller than the size measured prior to surgery (P < .0001).
The cross-sectional area of the median nerve was significantly correlated with
that of the ulnar nerve (P < .05).
However, no statistically significant difference was found between the patients
with carpal tunnel syndrome and controls in ulnar nerve conduction. There were
no statistically significant differences in nerve conduction study results or
cross-sectional area of the ulnar nerve between patients with carpal tunnel
syndrome with and without extramedian symptoms.
Conclusions—The cross-sectional areas of the ulnar and
median nerves at the wrist are increased in patients with carpal tunnel
syndrome. Also, the cross-sectional area of the ulnar nerve is decreased after
carpal tunnel release.
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Received February 25, 2015.
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Revision received March 31, 2015.
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Accepted April 13, 2015.
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© 2016 by the American Institute of Ultrasound in Medicine
Role of Sonography in Clinically Occult Femoral Hernias
Objectives—The purpose of this article is to evaluate
the diagnostic accuracy of sonography in clinically occult femoral hernias and
to describe our sonographic technique.
Methods—The clinical and imaging data for 93 outpatients referred by
general surgeons, all of whom underwent sonographic evaluation and surgery,
were reviewed retrospectively. Of these, 55 patients who underwent surgical
exploration for groin hernias within 3 months of sonography and met all
inclusion criteria were included in the study. The sonographic technique
involves using the pubic tubercle as an osseous landmark to identify and
appropriately visualize the femoral canal. The Valsalva maneuver is then used
to differentiate the movement of normal fat (a potential pitfall) from true
herniation in the femoral canal. Surgical findings were used as the reference
standard by which sonographic results were judged. Two-by-two contingency
tables were used to calculate the sensitivity, specificity, positive predictive
value, and negative predictive value.
Results—In these 55 patients, surgery revealed 15 femoral hernias. Eight
femoral hernias occurred in women, and 7 occurred in men. For diagnosing
femoral hernias, sonography demonstrated sensitivity of 80%, specificity of
88%, a positive predictive value of 71%, and a negative predictive value of
92%. True-positive cases of femoral hernias have a sonographic appearance of a
hypoechoic sac with speckled internal echoes. When examining during the
Valsalva maneuver, a femoral hernia passes deep to the inguinal ligament,
expands the femoral canal, displacing the normal canal fat, and effaces the
femoral vein.
Conclusions—Sonography can exclude femoral hernias
with high confidence in light of its exceptional negative predictive value.
With attention to technique and imaging criteria, the diagnostic accuracy of
sonography can be enhanced.
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Received February 25, 2015.
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Revision received April 6, 2015.
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Accepted May 6, 2015.
Defining Competencies for Ultrasound-Guided Bedside Procedures
Consensus Opinions From Canadian Physicians
Objectives—This study sought to define the
competencies in ultrasound knowledge and skills that are essential for medical
trainees to master to perform ultrasound-guided central venous catheterization,
thoracentesis, and paracentesis.
Methods—Experts in the 3 procedures were identified by a snowball
technique through 3 Canadian tertiary academic health centers. Experts
completed 2 rounds of surveys, including an 88-item central venous
catheterization survey, a 96-item thoracentesis survey, and an 89-item
paracentesis survey. For each item, experts were asked to determine whether the
knowledge/skill described was essential, important, or marginal. Consensus on
an item was defined as agreement by at least 80% of the experts. For items on
which consensus was not reached during the first round of surveys, a second
survey was created in which the experts were asked to rate the item in a binary
fashion (essential/important versus marginal/unimportant).
Results—Of the 27 experts invited to complete each survey, 25 (93%)
completed the central venous catheterization survey; 22 (81%) completed the
thoracentesis survey; and 23 (85%) completed the paracentesis survey. The
experts represented 8 specialties from 8 cities within Canada. A total of 22,
32, and 28 items were determined to be essential competencies for central
venous catheterization, thoracentesis, and paracentesis, respectively, whereas
47, 38, and 42 competencies were determined to be important, and 8, 13, and 10
were determined to be marginal. The ability to perform real-time direct
ultrasound guidance was considered essential only for the performance of
central venous catheterization insertion.
Conclusions—Our study presents expert
consensus-derived ultrasound competencies that should be considered during the
design and implementation of procedural skills training for learners.
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Received February 25, 2015.
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Revision received March 27, 2015.
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Accepted May 8, 2015.
B-Lines on Pediatric Lung Sonography
Comparison With Computed Tomography
Objectives—Sonographic artifacts known as B-lines can
been used to estimate alterations of lung parenchyma. Multiple B-lines on
sonography are seen in congestive heart disease, interstitial lung disease,
respiratory infections, and neonates. The aim of this study was to compare the
amount of B-lines on sonography to the extent of parenchymal changes on
computed tomography (CT) in children.
Methods—Lung sonography was performed on 60 patients aged 18 years and
younger referred for chest CT at our institution. B-lines were counted from 5
anterolateral intercostal spaces bilaterally. The CT findings were documented
and graded as absent, minimal, partial, or complete.
Results—The number of B-lines on sonography increased consistently with
the growing extent of parenchymal changes on CT. The differences in the B-line
counts between the patients grouped according to the extent of parenchymal
changes on CT were statistically significant except between patients with
minimal and no changes (P < .01
Kruskal-Wallis and Tukey tests).
Conclusions—The number of B-lines on sonography
correlates with the extent of parenchymal changes on CT. Various parenchymal
changes were seen in patients with B-lines on sonography. B-lines were more
frequently seen in patients with no changes on CT when imaged during general
anesthesia.
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Received April 2, 2015.
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Revision received April 24, 2015.
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Accepted May 14, 2015.
Quantitative Ultrasound Elastography With an Acoustic Coupler
for Achilles Tendon Elasticity
Measurement Repeatability and Normative Values
Objectives—The purposes of this study were to measure
intraobserver and interobserver repeatability of quantitative elastography
using an acoustic coupler for the Achilles tendon, to compare elastographic
values among different age groups, and to assess the correlation between
quantitative and conventional qualitative measurements.
Methods—One hundred asymptomatic Achilles tendons of 50 volunteers were
examined. For quantitative elastography, the strain value of the tendon was
divided by that of the acoustic coupler with a known Young modulus, and the
strain ratio was calculated. B-mode image assessment and qualitative
elastography were also performed. Intraobserver repeatability and interobserver
repeatability of strain ratio measurements were calculated. The strain ratios
were compared among age groups by the Kruskal-Wallis test. Additionally, strain
ratios for each B-mode grade and qualitative elastographic grade were compared
by the Wilcoxon signed rank test.
Results—Intraobserver repeatability intraclass correlation coefficient
(1, 3) values were 0.87 and 0.93, respectively. The correlation coefficient
between the observers’ measurements was 0.61. The strain ratio for the 30s age
group was 0.27, which was significantly lower than the values for the other age
groups (P < .001). Although 97 of 100 tendons were
normal on B-mode evaluations, 36 of the 97 tendons were degenerated on
qualitative elastography and also had higher strain ratio values than normal
tendons.
Conclusions—Quantitative elastography using an
acoustic coupler is a reproducible technique for measuring the elasticity of
the Achilles tendon. It may detect early tendon degeneration that is not
depicted on B-mode imaging.
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Received January 10, 2015.
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Revision received February 14, 2015.
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Accepted May 15, 2015.
Sonography of Abdominal Wall Masses and Masslike Lesions
Correlation With Computed Tomography and Magnetic Resonance
Imaging
Sonography is usually regarded as a first-line imaging modality
for masses and masslike lesions in the abdominal wall. A dynamic study focusing
on a painful area or palpable mass and the possibility of ultrasound-guided
aspiration or biopsy are the major advantages of sonography. On the other hand,
cross-sectional imaging clearly shows anatomy of the abdominal wall; thereby,
it is valuable for diagnosing and evaluating the extent of diseases.
Cross-sectional imaging can help differentiate neoplastic lesions from
non-neoplastic lesions. This pictorial essay focuses on sonographic findings of
abdominal wall lesions compared with computed tomographic and magnetic
resonance imaging findings.
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Received March 11, 2015.
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Revision received April 27, 2015.
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Accepted May 2, 2015.
