Differences in Anatomic Adaptation and Injury Patterns Related to Valgus Extension Overload in Overhead Throwing Athletes

The purpose of our study was to determine differences in adaptative and injury patterns in the elbow related to valgus extension overload (VEO) in overhead throwing athletes by age. A total of 86 overhead throwing athletes and 23 controls underwent MRI or MR arthrography (MRA) of the elbow. Throwing athletes were divided by age into three groups: ≤16 years (26 subjects), 17-19 years (25 subjects), and ≥20 years (35 subjects). Consensus interpretation of each MRI was performed, with measurements of ulnar collateral ligament (UCL) thickness and subchondral sclerosis at the radial head, humeral trochlea, and olecranon process. A higher frequency of apophyseal and stress injuries was seen in adolescent athletes and increased incidence of soft tissue injuries was observed in older athletes. Early adaptive and degenerative changes were observed with high frequency independent of age. Significant differences were observed between athletes and controls for UCL thickness (p < 0.001) and subchondral sclerosis at the radial head (p < 0.001), humeral trochlea (p < 0.001), and olecranon process (p < 0.001). Significant differences based on athlete age were observed for UCL thickness (p < 0.001) and subchondral sclerosis at the olecranon process (p = 0.002). Our study highlights differences in anatomic adaptations related to VEO at the elbow between overhead throwing athletes and control subjects, as well as across age in throwing athletes.

Luminal obstruction in uncomplicated appendicitis: Detection with sonography and potential clinical implications

PURPOSE

To determine the frequency of luminal obstruction on appendiceal graded compression sonography (US) in patients with uncomplicated appendicitis and test the hypothesis that this frequency is similar to the failure rates of primary antibiotic therapy for uncomplicated appendicitis when treatment selection is based on CT findings.

METHODS

Sonograms of 150 consecutive patients with appendicitis diagnosed on ultrasound (US) and proven histopathologically were retrospectively evaluated; 114 (76.0%) had uncomplicated appendicitis, that is, appendicitis without gangrene or perforation, and were evaluated for appendicolithiasis and lymphoid hyperplasia using previously published sonographic criteria, and for luminal obstruction.

RESULTS

Of the 114 patients with uncomplicated appendicitis, US demonstrated no luminal obstruction in 74 (64.9%) and luminal obstruction in 40 (35.1%, P = .018), the latter including 16 (40.0%) with lymphoid hyperplasia and 24 (60.0%, P = .074) with appendicolithiasis.

CONCLUSIONS

US demonstrated luminal obstruction in 35.1% of patients with uncomplicated appendicitis, similar to the published failure rates of antibiotic therapy when treatment selection is based on CT. This confirms the hypothesis, supporting the possibility that undiagnosed luminal obstruction may account for treatment failures when patients are selected by CT for primary antibiotic therapy, and suggests a role for US in selecting patients without luminal obstruction for antibiotic therapy.

Diagnostic Accuracy of Various Imaging Modalities for Suspected Lower Extremity Stress Fractures: A Systematic Review With Evidence-Based Recommendations for Clinical Practice

BACKGROUND

The literature is filled with conflicting findings regarding diagnostic accuracy and protocols for imaging suspected lower extremity stress fractures. The absence of systematic reviews on this topic has limited the development of evidence-based recommendations for appropriate imaging protocols in cases of suspected lower extremity stress fractures.

PURPOSE

To determine the diagnostic accuracy statistics of imaging modalities used to diagnose lower extremity stress fractures and to synthesize evidence-based recommendations for clinical practice.

STUDY DESIGN

Systematic review.

METHODS

A generic search strategy for published studies was performed using multiple databases. A study was eligible for inclusion if it met all of the following criteria: (1) at least 1 diagnostic imaging modality was studied, (2) at least 1 radiological reference standard was used, (3) the study reported or allowed computation of diagnostic accuracy statistics (sensitivity, specificity, positive likelihood ratio, negative likelihood ratio), (4) a full-text version was available, (5) the article was written in English, and (6) the study included lower extremity stress fractures. Studies that examined asymptomatic individuals or patients with fractures due to disease or pharmacologic intervention were excluded.

RESULTS

Reported sensitivity and specificity (95% CI) were as follows: For conventional radiography, sensitivity ranged from 12% (0%-29%) to 56% (39%-72%) and specificity ranged from 88% (55%-100%) to 96% (87%-100%). For nuclear scintigraphy (NS), sensitivity ranged from 50% (23%-77%) to 97% (90%-100%) and specificity from 33% (12%-53%) to 98% (93%-100%). For magnetic resonance imaging (MRI), sensitivity ranged from 68% (45%-90%) to 99% (95%-100%) and specificity from 4% (0%-11%) to 97% (88%-100%). For computed tomography, sensitivity ranged from 32% (8%-57%) to 38% (16%-59%) and specificity from 88% (55%-100%) to 98% (91%-100%). For ultrasound, sensitivity ranged from 43% (26%-61%) to 99% (95%-100%) and specificity from 13% (0%-45%) to 79% (61%-96%).

CONCLUSION

MRI was identified as the most sensitive and specific imaging test for diagnosing stress fractures of the lower extremity. When MRI is available, NS is not recommended because of its low specificity, high dosage of ionizing radiation, and other limitations. Conventional radiographs are likely to result in false negatives upon initial presentation, particularly in the early stages of stress fracture, and in some cases may not reveal an existing stress fracture at any time. A diagnostic imaging algorithm was developed with specific recommendations for cost-efficient imaging of low-risk and high-risk suspected stress fractures.

Comparative Diagnostic Utility of Low-Dose Breast-Specific Gamma Imaging to Current Clinical Standard

To retrospectively compare low-dose (7-10 mCi) to high-dose (15-30 mCi) breast-specific gamma imaging (BSGI) in the detection of breast cancer. A retrospective review of 223 consecutive women who underwent BSGI exam between February 2011 and August 2013 with subsequent pathologic analysis was performed. Women were divided into low-dose and high-dose groups. The results of BSGI and pathology were compared, and the sensitivity, positive predictive value (PPV), and negative predictive value (NPV) were determined. A subgroup analysis was performed to evaluate specificity using benign follow-up imaging to establish true-negative results. There were 223 women who met inclusion criteria with 109 patients with 153 lesions in the low-dose group and 114 patients with 145 lesions in the high-dose group. Pathologic correlation demonstrates sensitivities of 97.6% (95% CI = 90.9-99.6%) and 94.6% (95% CI = 84.2-98.6%; p = 0.093), PPVs of 62.1% (95% CI = 53.2-70.3%) and 50.5% (95% CI = 40.6-60.3%, p = 0.089), and NPVs of 90.5% (95% CI = 68.2-98.3%) and 92.5% (95% CI = 78.5-98.0%, p = 0.781) in the low-dose and high-dose groups, respectively. Subgroup analysis included 72 patients with 98 lesions in the low-dose group and 116 patients with 132 lesions in the high-dose group, with a specificity of 53.7% (95% CI = 39.7-67.1%) and 66.3% (95% CI = 56.2-75.2%%, p = 0.143), respectively. Low-dose BSGI demonstrated high sensitivity and NPV in the detection of breast cancer comparable to the current standard dose BSGI, with moderate specificity and PPV in a limited subgroup analysis, which was associated with a substantial number of false-positives.

A renewable-reagent fiber-optic sensor for measurement of high acidities

A renewable-reagent fiber-optic HNO(3) sensor was developed for HNO(3) measurement in the 0.1-10.0 M range. The HNO(3) sensor employs a tubular Nafion cation-exchange membrane to extract acid species from an external HNO(3) sample into an internal flowing reagent solution. In high-concentration HNO(3) samples, incomplete HNO(3) dissociation results in a significant concentration of neutral HNO(3) species in addition to protons. As both neutrals and protons are potentially membrane-permeable species, various reagent compositions were tested to examine the contributions of both acid transfer mechanisms. Continuous reagent flow limited internal acid accumulation and transferred reagent to the sensor optical detection cell. All reagent compositions included cresol red as a colorimetric indicator, which was measured within the sensor detection cell. Careful fiber-optic alignment provided sufficient light throughput in a backscatter illumination mode to allow use of a photodiode array detector for visible spectral acquisition. The use of Ca(2+) as a reagent countercation produced notable reductions in HNO(3) sensor response to interferent cations and temperature changes. Sensor measurement of HNO(3) samples in the tested concentration range produced average relative standard deviations of less than 0.4%. Control over reagent flow rate should allow for extension of the HNO(3) sensor measurement range to 16.0 M HNO(3).