Biopsy of CT-Occult Bone Lesions Using Anatomic Landmarks for CT Guidance.

OBJECTIVE: The purpose of this study is to evaluate the histopathologic diagnostic yield, sample size, procedural time, and dose-length product (DLP) for the biopsy of CT-occult lesions found at MRI or PET or both. MATERIALS AND METHODS: A retrospective review of our radiology information system for biopsies of CT-occult lesions using CT guidance from January 1, 2010, through December 31, 2014, was performed and compared with a selection of CT-guided biopsies of CT-evident bone lesions during the same period. The data were then evaluated for diagnostic yield of histopathologic diagnosis, procedural time, use of sedation medication, DLP, and size of specimens obtained. RESULTS: A total of 30 CT-occult biopsies met the inclusion criteria. Twenty-seven of those biopsies had results that were concordant with the patient's primary histopathologic diagnosis, imaging findings, and clinical course. In the CT-evident lesion group, concordant histopathologic abnormalities were identified in 27 of 30 patients. There was a statistically significant increase in number of samples obtained for the CT-evident lesions compared with CT-occult lesions. There was no statistically significant difference in total specimen length, DLP, number of CT scans, procedural time, or use of sedation medication between the CT-occult and CT-evident biopsy groups. CONCLUSION: Biopsy of CT-occult lesions using anatomic landmarks achieves diagnostic yields similar to those for CT-guided biopsy of CT-evident lesions.

Proliferative myositis: expanding the differential diagnosis of a soft tissue mass in infancy.

Proliferative myositis, a pseudosarcomatous lesion of skeletal muscle, is quite rare in the pediatric population. While benign, it is not always recognized as such, and may be treated with an extensive resection that can result in permanent disfigurement. We report a case of an infant with the diagnosis of proliferative myositis, who to our knowledge is the youngest patient to be evaluated with magnetic resonance imaging (MRI). Although the MRI findings are non-specific, we highlight the importance of considering proliferative myositis in the differential diagnosis of a soft tissue mass, which ultimately might prevent an overly aggressive resection in a child.

EMG and MRI are independently related to shoulder external rotation function in neonatal brachial plexus palsy.

BACKGROUND: Few studies exist with regard to the ability of electromyography (EMG) and volumetric magnetic resonance imaging (MRI) of the infraspinatus muscle to complement the physical assessment of active global shoulder external rotation (GER) in the neonatal brachial plexus palsy (NBPP) population. Therefore, the purpose of this study was to evaluate the relationships of EMG and MRI with active GER based on analysis of the infraspinatus muscle. METHODS: Seventy-four NBPP patients (mean age, 5 y 1 m; range, 1 y 1 m to 13 y 3 m) who had undergone physical examination of the shoulder, EMG evaluation of the infraspinatus muscle, and shoulder MRI were included in this study. The outcome variable active GER was dichotomized into <0 degree active GER (poor) and ≥0 degree active GER (good). The interference pattern on EMG of the infraspinatus muscle was graded on a 6-point scale and dichotomized into ≤4 and ≥5. On shoulder MRI, infraspinatus muscle volume was measured. The infraspinatus muscle interference pattern and volume were compared with active GER. RESULTS: Interference pattern on EMG of the infraspinatus muscle was significantly related to the Mallet Score (P=0.0022), with a poor interference pattern associated with an approximately 7 times higher likelihood [odds ratio=7.391; 95% confidence interval (2.054, 26.588)] of poor active GER. Infraspinatus muscle volume decrease on MRI was also significantly related to active GER (P=0.0413), with each percent volume decrease corresponding to an increase of 0.094 in the odds of having a poor Mallet Score for active GER [odds ratio=1.094; 95% confidence interval (1.004, 1.193)]. CONCLUSIONS: The interference pattern of the infraspinatus muscle on EMG and the infraspinatus muscle volume on MRI are strongly related to active GER as assessed by the Mallet Score. Integrating clinical assessment with electrophysiological and imaging findings may improve the accuracy in evaluating shoulder dysfunction in NBPP and provide improved guidance in selecting interventions specific to the patient's pattern of deficits. LEVEL OF EVIDENCE: Diagnostic study, level II.

Photoacoustic discrimination of viable and thermally coagulated blood using a two-wavelength method for burn injury monitoring.

Discriminating viable from thermally coagulated blood in a burn wound can be used to profile burn depth, thus aiding the removal of necrotic tissue. In this study, we used a two-wavelength photoacoustic imaging method to discriminate coagulated and non-coagulated blood in a dermal burn phantom. Differences in the optical absorption spectra of coagulated and non-coagulated blood produce different values of the ratio of peak photoacoustic amplitude at 543 and 633 nm. The absorption values obtained from spectroscopic measurements indicate that the ratio of photoacoustic pressure for 543 and 633 nm for non-coagulated blood was 15.7:1 and 1.6:1 for coagulated blood. Using planar blood layers, we found the photoacoustic ratios to be 13.5:1 and 1.6:1, respectively. Using the differences in the ratios of coagulated and non-coagulated blood, we propose a scheme using statistical classification analysis to identify the different blood samples. Based upon these distinctly different ratios, we identified the planar blood samples with an error rate of 0%. Using a burn phantom with cylindrical vessels containing coagulated and non-coagulated blood, we achieved an error rate of 11.4%. These results have shown that photoacoustic imaging could prove to be a valuable tool in the diagnosis of burns.