Epipericardial Fat Pad Necrosis-A Rare Cause of Chest Pain in an Adolescent

ABSTRACT

Epipericardial fat necrosis is a rare cause of acute pleuritic chest pain reported in approximately 40 cases. This diagnosis mimics a myocardial infarction, pulmonary embolism, or pericarditis; however, the cardiac enzymes and electrocardiogram are usually normal. We present the first reported case of epipericardial fat necrosis in an adolescent.

Diagnostic performance and role of the contrast enema for low intestinal obstruction in neonates

PURPOSE

We aim to evaluate the diagnostic performance and relationship between clinical characteristics, imaging findings, and final diagnosis for the neonatal contrast enema (CE).

METHODS

Retrospective 10-year review of all neonatal CEs including imaging findings, clinical information, indication, and final diagnosis from discharge summaries, surgical reports, and pathology (reference standard). Two blinded pediatric radiologists reinterpreted 366 CEs for obstruction, microcolon, rectosigmoid index (RSI), serrations, meconium, ileal cut-off, transition zone, diagnosis, and level of confidence. CE diagnostic performance was calculated versus reference standard.

RESULTS

Diagnoses included Hirschsprung disease (HD) (15.8%), small left colon syndrome (14.8%), small intestinal atresia/colonic atresia (SIA/CA) (12.6%), meconium ileus (MI) (4.4%), and normal (48.9%). CE had a moderate specificity (87.7%) and low sensitivity (65.5%) for HD; abnormal RSI and serrations showed high specificities (90.3%, 97.4%) but low sensitivities (46.6%, 17.2%). CE showed high specificity (97.4%) and low sensitivity (56.3%) for MI blinded to cystic fibrosis status. Microcolon was specific (96.6%) but not sensitive (68.8%) for MI. CE showed highest PPV (73.1%) (specificity 95.6%, sensitivity 82.6%) for SIA/CA. Microcolon with an abrupt cut-off was specific (99.1%) but not sensitive (41.3%) for atresias.

CONCLUSION

Neonatal CE demonstrates high specificities and low to moderate sensitivities across all diagnoses, with lowest performance in HD.

CLINICAL TRIAL REGISTRATION

None.

Chondroid lipoma: multimodality imaging in a 9-year-old female

Chondroid lipomas are rare, benign lipomatous tumors that occur most frequently in adults during the fourth decade of life. While a female predominance was observed in the initial series of 20 cases described in 1993, the subsequent 49 reported cases do not support a strong gender predilection. We report a case of a chondroid lipoma presenting in a 9-year-old female as a painless, enlarging, left gluteal mass. This is the second case to be reported in the first decade of life and the fourth pediatric case reported in the literature (age < 21). We review the imaging and pathology findings as well as present a comprehensive review of the current literature.

Clinical Significance of US Artifacts

Artifacts are frequently encountered at clinical US, and while some are unwanted, others may reveal valuable information related to the structure and composition of the underlying tissue. They are essential in making ultrasonography (US) a clinically useful imaging modality but also can lead to errors in image interpretation and can obscure diagnoses. Many of these artifacts can be understood as deviations from the assumptions made in generating the image. Therefore, understanding the physical basis of US image formation is critical to understanding US artifacts and thus proper image interpretation. This review is limited to gray-scale artifacts and is organized into discussions of beam- and resolution-related, location-related (ie, path and speed), and attenuation-related artifacts. Specifically, artifacts discussed include those related to physical mechanisms of spatial resolution, speckle, secondary lobes, reflection and reverberation, refraction, speed of sound, and attenuation. The underlying physical mechanisms and appearances are discussed, followed by real-world strategies to mitigate or accentuate these artifacts, depending on the clinical application. Relatively new US modes, such as spatial compounding, tissue harmonic imaging, and speckle reduction imaging, are now often standard in many imaging protocols; the effects of these modes on US artifacts are discussed. The ability of a radiologist to understand the fundamental physics of ultrasound, recognize common US artifacts, and provide recommendations for altering the imaging technique is essential for proper image interpretation, troubleshooting, and utilization of the full potential of this modality. ^©RSNA, 2017.

Multi-parametric MR imaging of the anterior fibromuscular stroma and its differentiation from prostate cancer

PURPOSE

To describe MP-MRI features of the normal anterior fibromuscular stroma (AFMS) and identify MR imaging findings that can differentiate it from anterior prostate cancer.

METHODS

We reviewed MP-MR images and histopathology of patients who underwent pre-operative MRI and prostatectomy between October 2012 and August 2014. Thirty-seven patients with anterior prostate cancer larger than 5 mm and 40 patients with no anterior cancer were included in this study. After correlation with histology and MR images, the size, symmetry, T2, DWI characteristics, and enhancement pattern of normal AFMS and anterior prostate cancer were compared.

RESULTS

Normal AFMS was hypointense and symmetric on T2-weighted images (37/40, 93%), whereas anterior prostate cancers, while also hypointense on T2-weighted images, were predominantly asymmetric (6/37, 16%) (P < 0.001). On high b-value DWI, AFMS was predominantly hypointense (36/40, 90%), whereas anterior prostate cancers were predominantly hyperintense (30/37, 81%) compared to the normal peripheral zone (P < 0.001). The mean ADC and tenth percentile ADC values of anterior prostate cancers were lower than normal AFMS (7.14 vs. 8.33 (10^-4 mm²/s), P < 0.01) and (5.73 vs. 6.95 (10^-4 mm²/s), P < 0.01), respectively. On DCE-MR images, AFMS demonstrated a type 1 enhancement curve (35/39, 90%), whereas anterior prostate cancers demonstrated only either a type 3 (23/37, 62%) or type 2 enhancement curve (14/37, 38%) (P < 0.001).

CONCLUSIONS

Symmetric T2 appearance, hypointense high b-value DWI signal, relatively higher ADC values, and Type 1 enhancement pattern of the AFMS can be helpful in its differentiation from anterior prostate cancers.

Effect of comfort pads and incubator design on neonatal radiography

BACKGROUND

There has been increasing interest in patient dose reduction in neonatal intensive care units. Removing comfort pads for radiography has been identified as a potential means to decrease patient dose.

OBJECTIVE

To assess the effect of comfort pads and support trays on detector entrance exposure (DEE) and image quality for neonatal radiography, and its implication for patient dose.

MATERIALS AND METHODS

Comfort pads and support trays from three incubator and warmer systems were examined. The attenuation of the primary beam by these structures was measured using a narrow beam geometry. Their effect on DEE and image quality was then assessed using typical neonatal chest radiography techniques with three configurations: 1) both the comfort pad and support included in the beam, 2) only the support tray included and 3) both the comfort pad and support tray removed.

RESULTS

Comfort pads and support trays were found to attenuate the primary beam by 6-15%. Eliminating these structures from the X-ray beam's path was found to increase the detector entrance exposure by 28-36% and increase contrast-to-noise ratio by more than 21%, suggesting room for patient dose reduction when the same image quality is maintained.

CONCLUSION

Comfort pads and tray support devices can have a considerable effect on DEE and image quality, with large variations among different incubator designs. Positioning the image detector directly underneath neonatal patients for radiography is a potential means for patient dose reduction. However, such benefit should be weighed against the risks of moving the patient.

Dynamic contact mechanics of radial tears of the lateral meniscus: implications for treatment

PURPOSE

To characterize the effect of radial tears (RTs) of the lateral meniscus and their subsequent treatment (inside-out repair, partial meniscectomy) on joint contact mechanics during simulated gait.

METHODS

Six human cadaveric knees were mounted on a simulator programmed to mimic human gait. A sensor was inserted below the lateral meniscus to measure peak joint contact pressure location, magnitude, and contact area. The following conditions were compared: intact meniscus, 30% RT (at the popliteal hiatus), 60% RT, 90% RT, repair, and partial meniscectomy. Data were analyzed in the midstance phase of gait (14% and 45%) when axial force was at its highest (2,100 N).

RESULTS

Intact knees had peak contact pressures of 5.9 ± 0.9 MPa and 6.4 ± 1.1 MPa at 14% and 45% of gait, respectively. RTs of up to and including 60% had no effect on pressure magnitude or location. RTs of 90% resulted in significantly increased peak pressure (8.4 ± 1.1 MPa) in the postero-peripheral aspect of the tibial plateau and reduced contact area versus the intact knee, at 45% of gait. Repair resulted in a significant decrease in peak pressure (7.7 ± 1.0 MPa) relative to 90% RT but had no effect on contact area. Partial lateral meniscectomy resulted in areas and pressures that were not significantly different from 90% tears (8.7 ± 1.5 MPa).

CONCLUSIONS

Simulated large RTs of the lateral meniscus in the region of the popliteal hiatus show unfavorable dynamic contact mechanics that are not significantly different from those resulting from a partial lateral meniscectomy. Pressure was significantly reduced with inside-out repair but was not affected by partial meniscectomy; contact area was not restored to that of the intact condition for either procedure.

CLINICAL RELEVANCE

Large RTs in the region of the popliteal hiatus show unfavorable dynamic contact mechanics.

Evaluation of acute cervical spine imaging based on ACR Appropriateness Criteria®

The objectives of this study were to determine the rate of acute blunt cervical spine injury at an academic urban level 1 trauma center and to evaluate the utilization of cervical spine imaging based on the established American College of Radiology (ACR) Appropriateness Criteria®. We retrospectively reviewed all radiography and CT imaging of the cervical spine performed over a year period in adult patients presenting with acute blunt cervical spine trauma. Exclusion criteria were children ≤17 years, non-acute trauma of ≥72 h, and penetrating trauma. Any fracture, dislocation, or ligamentous instability demonstrated by diagnostic imaging and requiring stabilization or specialized follow-up was defined as clinically significant cervical spine injury. A total of 1,325 cervical spine studies were reviewed in 1,245 patients; 32.7% (433/1,325) were cervical spine radiographs and 67.3% (892/1,325) were CT examinations. Approximately 1.5% (19/1,245) of the patients demonstrated clinically significant acute cervical spine injury. There were 6.4% (80/1,245) patients who received both cervical spine radiographs and CT as imaging evaluation. Based on the ACR Appropriateness Criteria®, all of the cervical spine radiographs performed (433) were determined to be "inappropriate" imaging in the setting of acute cervical spine injury.

Dynamic contact mechanics of the medial meniscus as a function of radial tear, repair, and partial meniscectomy

BACKGROUND

The menisci are integral to normal knee function. The purpose of this study was to measure the contact pressures transmitted to the medial tibial plateau under physiological loads as a function of the percentage of the meniscus involved by the radial tear or repair. Our hypotheses were that (1) there is a threshold size of radial tears above which contact mechanics are adversely affected, and (2) partial meniscectomy results in increased contact pressure compared with that found after meniscal repair.

METHODS

A knee simulator was used to apply physiological multidirectional dynamic gait loads across human cadaver knees. A sensor inserted below the medial meniscus recorded contact pressures in association with (1) an intact meniscus, (2) a radial tear involving 30% of the meniscal rim width, (3) a radial tear involving 60% of the width, (4) a radial tear involving 90% of the width, (5) an inside-out repair with horizontal mattress sutures, and (6) a partial meniscectomy. The effects of these different types of meniscal manipulation on the magnitude and location of the peak contact pressure were assessed at 14% and 45% of the gait cycle.

RESULTS

The peak tibial contact pressure in the intact knees was 6 +/- 0.5 MPa and 7.4 +/- 0.6 MPa at 14% and 45% of the gait cycle, respectively. The magnitude and location of the peak contact pressure were not affected by radial tears involving up to 60% of the meniscal rim width. Radial tears involving 90% resulted in a posterocentral shift in peak-pressure location manifested by an increase in pressure in that quadrant of 1.3 +/- 0.5 MPa at 14% of the gait cycle relative to the intact condition. Inside-out mattress suture repair of a 90% tear did not restore the location of the pressure peak to that of the intact knee. Partial meniscectomy led to a further increase in contact pressure in the posterocentral quadrant of 1.4 +/- 0.7 MPa at 14% of the gait cycle.

CONCLUSIONS

Large radial tears of the medial meniscus are not functionally equivalent to meniscectomies; the residual meniscus continues to provide some load transmission and distribution functions across the joint.

Enhanced survival of the LINCL mouse following CLN2 gene transfer using the rh.10 rhesus macaque-derived adeno-associated virus vector

Late infantile neuronal ceroid lipofuscinosis (LINCL) is a lysosomal storage disorder caused by mutations in the CLN2 gene and a deficiency of tripeptidyl peptidase I (TPP-I). Prior studies with adeno-associated virus (AAV) serotype 2 or 5 mediated transfer of the CLN2 complementary DNA to the central nervous system (CNS) of CLN2(-/-) mice cleared CNS storage granules, but provided no improvement in the phenotype or survival of this model of LINCL. In this study, AAV serotypes (AAV2, AAV5, AAV8, and AAVrh.10) were compared for the delivery of the same CLN2 expression cassette. AAVrh.10, derived from rhesus macaque, provided the highest TPP-I level and maximum spread beyond the site of injection. The AAVrh.10-based vector functioned equally well in naive rats and in rats previously immunized against human serotypes of AAV. When administered to the CNS of CLN2(-/-) mice, the AAVrh.10CLN2 vector provided widespread TPP-I activity comparable to that in the wild-type mice. Importantly, the AAVrh.10CLN2-treated CLN2(-/-) mice had significant reduction in CNS storage granules and demonstrated improvement in gait, nest-making abilities, seizures, balance beam function, and grip strength, as well as having a survival advantage.