Influence of patient rotational malpositioning on pelvic parameters assessed on lateral radiographs

Aim: To estimate the effect of patients' axial rotation (AR) during pelvic radiograph acquisition, on the reliability and validity of sagittal pelvic parameters. Materials and methods: Lateral digitally reconstructed radiographs (LDRRs) were obtained from the pelvic computed tomography (CT) scans of eight children and nine adults. Then, the AR of the pelvis was simulated and the corresponding LDRRs were reconstructed at 5°, 10°, 15°, and 20° of the AR. Pelvic parameters were measured digitally on each radiograph. Intra- and interobserver variability were evaluated at each AR position (three operators repeated the measurements three times each). The bias on each clinical parameter, in each AR position, was calculated relatively to the 0° position. Results: Interobserver variability increased similarly in children and adults with AR. It reached 4.4° for pelvic incidence and 4.7° for the sacral slope at 20° of AR. Biases on radiological parameters increased with AR and exceeded the acceptable threshold of errors when AR reached 10°. A linear regression was established (R2=0.834, p<0.0001) in order to estimate the AR of a patient on a lateral pelvic radiograph based on the measurement of the bifemoral distance normalized to the sagittal pelvic thickness. Conclusions: AR of patients during radiograph acquisition can be estimated in clinical practice, which would allow physicians to discard any radiographs where the calculated AR exceeded 10°

Positive Predictive Values of Lumbar Spine Magnetic Resonance Imaging Findings for Provocative Discography

Purpose The purpose of this study was to calculate the positive predictive value (PPV) of lumbar spine magnetic resonance imaging (MRI) findings for a painful disc using provocative discography. Materials and Methods Lumbar spine discography records and prediscography MRIs of 736 patients (2457 discs) who underwent discography for diagnostic purposes from 2003 to 2007 were retrospectively reviewed in an Institutional Review Board-exempt and Health Insurance Portability and Accountability Act-compliant protocol. Each level was identified as having high-intensity zone (HIZ) disc, disc protrusion, disc extrusion, or combination (any herniation type), disc bulge, disc degeneration, and spondylolisthesis. Statistical analysis used a 2 x 2 contingency table of significant discography results for each of the MRI variables to calculate P value and PPV with a confidence interval from a binomial distribution. Results An HIZ disc has a PPV of 0.71 (0.65-0.76, P = 4.31E - 44) for a provocative discography. A disc protrusion has a PPV of 0.79 (0.73-0.83, P = 2.68E - 53). A disc extrusion has a PPV of 0.93 (0.79-0.98, P = 1.34E - 14), a bulge of 0.43 (0.37-0.48, P = 0.002), and a degenerative disc of 0.32 (0.28-0.35, P = 0.08), and spondylolisthesis has a PPV of 0.67 (0.59-0.73, P = 1.70E - 20). A herniation of either type (extrusion or protrusion) has a PPV of 0.80 (0.75-0.84, P = 5.86E - 69). Conclusions Disc herniations and HIZ discs have high predictive value in identifying a pain generator. An extruded disc herniation has the highest PPV for discogenic pain

MRI findings associated with microscopic residual tumor following unplanned excision of soft tissue sarcomas in the extremities

MRI is often used to determine the presence of residual disease following unplanned excisions (UPE) of soft tissue sarcomas (STS). We sought to identify MRI features associated with histologic evidence of residual disease after TBE. This was an IRB-approved retrospective review of 27 patients with R1-type UPE of STS over a 32-month period, with subsequent MRI and TBE. MRI studies were retrospectively evaluated to determine depth of tissue involvement, presence of nodular enhancement, and maximum length of soft tissue edema normalized to extremity size. MRI findings were correlated with histology from unplanned excision and TBE. Among the 21 subjects, there were 13 males and 8 females, mean age 58. Eighteen of 21 STS were grade 2 or 3. Deep compartments were involved in 5/21 cases. Original margins were positive in 17/21 UPE, with inadequate margin assessment in the remaining 4 cases. Residual tumor was present at TBE in 11/21 cases; it was found in 4/6 cases with nodular enhancement and 7/15 cases without nodular enhancement (sensitivity = 0.36; specificity = 0.80; PPV = 0.67; NPV = 0.53). Increased extent of soft tissue edema increased the likelihood of residual tumor at TBE (OR = 35.0; 95% CI = 1.6 to 752.7; p = 0.023). Nodular enhancement is neither sensitive nor specific in predicting residual microscopic tumor in TBE following UPE. Extensive soft tissue edema on MRI after UPE increases the likelihood of finding a residual microscopic tumor, justifying ample margins at TBE and consideration of adjuvant therapy

Does Vasopressin Exacerbate Cerebral Edema in Patients with Severe Traumatic Brain Injury?

Arginine vasopressin (AVP) is often used as an alternative pressor to catecholamines (CATs). However, unlike CATs, AVP is a powerful antidiuretic that could promote edema. We tested the hypothesis that AVP promoted cerebral edema and/or increased requirements for osmotherapy, relative to those who received CATs, for cerebral perfusion pressure (CPP) management after traumatic brain injury (TBI). This is a retrospective review of 286 consecutive TBI patients with intracranial pressure monitoring at a single institution from September 2008 to January 2015. Cerebral edema was quantitated using CT attenuation in prespecified areas of gray and white matter. To maintain CPP >60 mm Hg, 205 patients required no vasopressors, 41 received a single CAT, 12 received AVP, and 28 required both. Those who required no pressors were generally less injured; required less hyperosmolar therapy and less total fluid; and had lower plasma Na, lower intracranial pressure, less edema, and lower mortality (all P < 0.05). Edema; daily mean, minimum, and maximum Na levels; and mortality were similar with AVP versus CATs, but the daily requirement of mannitol and 3 per cent NaCl were reduced by 45 and 35 per cent (both P < 0.05). In patients with TBI who required CPP therapy, AVP reduced the requirements for hyperosmolar therapy and did not delay resolution or increase cerebral edema compared with CATs