New Zealand rickettsia-like organism and Tenacibaculum maritimum vaccine efficacy study

A cohort of Chinook salmon juveniles was vaccinated, with an autogenous bivalent vaccine against New Zealand RLOs (NZ-RLO1) and Tenacibaculum maritimum. A proportion of the cohort was not vaccinated to act as controls. At smoltification, the fish were challenged with NZ-RLO1, NZ-RLO2, or T. maritimum. We found that challenge with T. maritimum by immersion in (7.5 × 105  cfu/mL of water) did not yield any pathology. Challenge with RLOs produced clinical signs that were more or less severe depending on the challenge route, dose or vaccination status. Survival was significantly higher for vaccinated fish within the groups challenged with NZ-RLO1 by intraperitoneal injection with a relative percent survival (RPS) of 48.84%. Survival was not significantly different between vaccinated and non-vaccinated fish for groups challenged with NZ-RLO2 by intraperitoneal injection or by NZ-RLO1 by immersion. Yet, anecdotally the clinical disease presentation (manifesting as haemorrhagic, ulcerative skin lesions) was more severe for the non-vaccinated fish. This study demonstrates that autogenous vaccine against NZ-RLO is protective against severe disease and death by NZ-RLO1 challenge which warrants implementation and further evaluation under field conditions. Yet, this study also highlights the importance of the route of administration and dose when evaluating pathogenicity and vaccine efficacy.

Mycoplasma bovis testing for the screening of semen imported into New Zealand

AIMS

To evaluate the fitness of three PCR assays for the detection of Mycoplasma bovis in dilute (extended) bovine semen, and a reverse transcriptase-PCR (RT-PCR) adaptation as a proxy for viability.

MATERIALS AND METHODS

Four commercial kit-based methods for nucleic acid extraction were compared to test for the presence of PCR inhibitors in nucleic acid extracted from undiluted and diluted semen. Then, analytical sensitivity, analytical specificity, and diagnostic specificity of two real-time PCR and one conventional PCR were evaluated for the detection of M. bovis DNA in semen and compared against microbial culture. Furthermore, an RT-PCR was adapted to detect RNA only and tested on viable and non-viable M. bovis to establish its ability to discriminate between the two.

RESULTS

No significant PCR inhibition was detected from the dilute semen. All DNA extraction methods except one were equivalent, regardless of semen dilution. The analytical sensitivity of the real-time PCR assays was estimated as 45.6 cfu per 200 µL semen straw (2.2 × 10² cfu/mL). The conventional PCR was 10 times less sensitive. No cross-reactivity was observed for the real-time PCR for any of the bacteria tested and the diagnostic specificity was estimated as 100 (95% CI = 94.04-100) %. The RT-PCR was poor in distinguishing between viable and non-viable M. bovis. The mean quantification cycle (Cq) values for RNA extracted from different treatments to kill M. bovis remained unchanged 0-48 hours after inactivation.

CONCLUSION AND CLINICAL RELEVANCE

The real-time PCR were fit for the purpose of screening dilute semen for the detection of M. bovis to prevent incursion via importation of infected semen. The real-time PCR assays can be used interchangeably. The RT-PCR could not reliably indicate the viability of M. bovis. Based on the results from this study, a protocol and guidelines have been produced for laboratories elsewhere that wish to test bovine semen for M. bovis.

Ophthalmological findings in patients with leukaemia in a Colombian population

OBJECTIVE

To report the ocular manifestations in patients with leukaemia.

METHODS

This is a retrospective, descriptive and observational study in patients with ocular manifestations of leukaemia.

RESULTS

A total of 14 eyes were evaluated corresponding to 8 patients (5 women and 3 men) with ocular manifestations of leukaemia. The mean age at diagnosis was 43 years (31-76 years). Six eyes corresponded to patients with acute myeloid leukaemia (AML), four eyes to acute lymphoid leukaemia (ALL), two eyes to chronic myeloid leukaemia (CML), and the remaining two belonged to patients with hairy cell leukaemia (HCL). The primary ocular findings were choroidal invasion in 12 eyes (85.7%), retinal infiltration in 4 eyes (28.6%), and neuro-ophthalmic disorders in 4 eyes (28.6%). The mean visual acuity improved from 0.689 to 0.449 (logMAR) (P=.012) after the systemic and intrathecal chemotherapy. Of the eight patients, four died from systemic complications of the underlying disease.

CONCLUSIONS

This is the first report of multiple ocular manifestations secondary to leukaemia in a Colombian population. It is important to keep in mind that this disease is included within the masquerade syndromes and that the ophthalmological findings that, while subtle, can also be devastating and be signs of a life-threatening disease.

AB0538 PREGNANCY OUTCOMES IN PATIENTS WITH TAKAYASU’S ARTERITIS: CASE SERIES

Background:

Takayasu’s arteritis (TA) is most prevalent in women of childbearing age. Although its activity and risk of relapse are low during pregnancy, up to 40% of patients may have unfavorable obstetric outcomes and therefore it is important to know their clinical behavior.

Objectives:

To describe the clinical features and obstetric outcomes of pregnant women with TA treated in a tertiary center.

Methods:

Retrospective evaluation of medical records of 6 pregnancies in 6 women with TAs treated in a tertiary center in Medellin, Colombia between 2011-2018.

Results:

Six women who were 17.5 (RI 9.25) years old at diagnosis and 24 (RI 8.25) years old at delivery, their disease duration were 5.5 (RI 10.5) years. Three patients had extensive aortic involvement classified as Numano type V, two as type IIB and one as type I. At delivery, three patients were active and required immunosuppressants, five had high blood pressure, one developed preeclampsia in the second trimester, one had severe mitral and tricuspid insufficiency with decreased ejection fraction of the left ventricle; two had aneurysms (left subclavian artery and ascending aorta). There were two fetal deaths, one due to intrauterine growth restriction and placental insufficiency and another of unknown etiology; both patients with disease activity, extensive aortic condition and arterial hypertension; no pregnancy resulted in abortion or preterm birth. Five deliveries were by caesarean section by maternal indication; there was no aortic dissection, aneurismal rupture or cerebral hemorrhage (table).

Table

Patient’s characteristics

PatientAge at diagnosisAge at deliveryClinical featuresHata-Numano classificationMaternal outcomeFetal outcome1617HT, absence of left brachial and radial pulses, L carotid and subclavian murmurs, LVEF 47%VHT, C-sectionTerm delivery, SGA22226HT, abscence of L brachial and radial pulses, L carotid and subclavian murmurs, dyspnea, anginaV(plus pulmonary)HT, vaginal birthPlacental insufficiency, IUGR, fetal death31438HT, abscence of L brachial and radial pulses, L carotid and subclavian murmurs, intermittent claudication, dyspnea, aortic regurgitationIIBHT, C-sectionTerm delivery, SGA41824HT, malaise,, abscence of L brachial and radial pulses, intermittent claudication, arthralgiaIIBPreeclampsia, C-sectionTerm delivery, SGA51722Fever, malaise, intermittent claudication, arthralgiaIC-sectionTerm delivery, SGA62124HT, abscense of bilateral femoral, popliteal, tibial and pedial pulses, headache, dizziness, amaurosisVHT, C-sectionFetal death

HT: hypertension; L: left; LVEF: left ventricular ejection fraction; C-section: cesarean section; SGA: small for gestational age; IUGR: intrauterine growth restriction

Conclusion:

Pregnant women with active disease and extensive aortic condition presented unfavorable obstetric results, suggesting that an inadequate control of vasculitis may lead to greater maternal-fetal complications.

References:

[1]Assad APL, da Silva TF, Bonfa E, Pereira RMR. Maternal and Neonatal Outcomes in 89 Patients with Takayasu Arteritis (TA): Comparison Before and After the TA Diagnosis. J Rheumatol. 2015 Oct;42(10):1861–4.

[2]Hidaka N, Yamanaka Y, Fujita Y, Fukushima K, Wake N. Clinical manifestations of pregnancy in patients with Takayasu arteritis: experience from a single tertiary center. Arch Gynecol Obstet. 2012 Feb;285(2):377–85.

Disclosure of Interests:

None declared

AB0535 ARE THE NEUTROPHIL/LYMPHOCYTE RATIO (NLR) AND PLATELET/LYMPHOCYTE RATIO (PLR) USEFUL TO COMPARED WITH ACUTE PHASE REACTANTS (ESR/CRP) FOR DIAGNOSIS AND PROGNOSIS OF PATIENTS WITH ACTIVE TAKAYASU’S ARTERITIS (TAK)?: AN ANALYSIS BASED ON ROC AND KAPLAN-MEIER CURVES IN A LATIN AMERICAN POPULATION

Background:

The NIH criteria are the main measure to determine activity in TAK. NLR and PLR appear promising to predict disease activity(1). TAK is one of the most frequent vasculitis in Colombia with a prevalence of 13.3%; however, in more recent years the information is sparse about TAK clinical behavior in our region, which leads to a late diagnosis. Although survival has improved with immunosuppressive treatment, relapses remain high especially in the first year of diagnosis

Objectives:

Compare NLR and PLR with ESR/CRP to predict TAK activity

Show survival and relapse in patients with TAK followed to 7 y

Methods:

Retrospective cohort of 43 patients with TAK between 2011-2018 with prospective follow-up of relapses and mortality. 88% fulfilled the ACR 1990 criteria. The disease activity was determined according to NIH criteria: active disease (n=34) and inactive disease (n=9). Through bivariate analysis, we compared the clinical and radiologic characteristics between age groups (table 1) using the Pearson test and Wilcoxon range test. Value of p <0.05 was statistically significant. Survival and relapse analysis were performed using Kaplan-Meier plots. Sensitivity (Sn), specificity (Sp) and area under the curve (AUC) were determined for NLR, PLR, ESR and CRP by receiver-operating curves (ROC) compared to NIH criteria.

Table 1.

Comparison of Clinical Features in Patients with TAK

No (%) of PatientsAge at diagnosis≤40 y (n=32)Age at diagnosis≥40 y(n=11)P valueFemale30 (94)11 (100)0.39Age at symptom onset (years), median: (Interquartile range –IQR-)20 (17-25)52 (47-57)0.110Time from symptom onset to diagnosis (months) median (IQR)9.5 (2-15)36 (1.5-24)0.774Smoking2 (6)6 (54)0.002Dyslipidemia7 (22)6 (54)0.042ACR Criteria 1990Claudication of extremities14 (43)5 (45)0.922Upper extremities blood pressure discrepancy > 10 mmHg19 (59)6 (54)0.779Decreased brachial artery pulse24 (75)9 (82)0.644Subclavian artery or aorta bruit19 (59)6 (54)0.774Arteriographic abnormality27/27 (100)11/11 (100)1.0ESR (mm/h), median (IQR)56 (23-115)38 (33-76)0.011CRP (mg/dL), median (IQR)1.35 (0.4-3.4)3 (1.49-18.5)0.020Creatinine (mg/dL), median (IQR)0.72 (0.6-0.83)0.84 (0.75-1)0.007Hata-Numano classification I15%18% IIa6%9% IIb6% III6% IV3%9% V59%64%

Results:

41 patients were women (96%) with a median age at diagnosis of 22 y and an interval from the onset of disease to diagnosis of 12 months (IR:1-168 m). The population over 40 years had a greater comorbidities burden (54% had history of smoking and dyslipidemia) and a major interval between the onset of disease and the diagnosis (36 months vs 9.5 months). Most frequent vascular phenotypes were types V (62%) and I (16%). NLR and PLR showed poor performance to predict activity compared with CRP; NLR level of 1.74 showed to be the predictive cut-off value for active TAK (Sn: 85.3%, Sp: 37.5%, AUC = 0.563). PLR level of 112.5 was found to be the predictive cut-off value for active TAK (Sn: 76.5%, Sp: 50%, AUC = 0.517). The CRP was the most accurate biomarker (Sn: 79.4%, Sp: 75%, AUC = 0.761) while the ESR was lower to predict activity (Sn: 63.6%, Sp: 75%, AUC = 0.598) (figure 1). At 5 years, survival was 83% and 50% of patients had presented at least one relapse (figure 2)

Conclusion:

Our data does not support the use of NLR or PLR to differentiate relapse and remission in TAK. CRP had better diagnostic performance than ESR in the prediction of activity compared to NIH criteria. The 5-year survival in this cohort is below that reported after 1985 (reported survival: 90-96%)(2)

References :

[1]Pan L, et al. Platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio associated with disease activity in patients with Takayasu’s arteritis: a case-control study. BMJ Open 2017; 7: e014451

[2]Schmidt J, et al. Diagnostic features, treatment, and outcomes of Takayasu arteritis in a US cohort of 126 patients, Mayo Clin Proc. 2013; 88(8): 822-30

Disclosure of Interests:

None declared

Tuberculous sacroiliitis in a patient with systemic lupus erythematosus: a case report and literature review

Systemic lupus erythematosus (SLE) patients are at higher risk of developing opportunistic infections such as tuberculosis (TB), especially extrapulmonary forms like osteoarticular TB, compared to the general population. However, tuberculous sacroiliitis has been scarcely reported in these patients. We present a 34-year-old woman with SLE who developed articular tuberculosis simultaneously affecting the right sacroiliac joint and the left knee. The patient was successfully treated with antituberculosis therapy for nine months. In this case, in addition to the immunological abnormalities of lupus, the long-term glucocorticoid therapy at high dosages was the main risk factor for the development of osteoarticular tuberculosis.

Age dependency of nervous necrosis virus infection in barramundi Lates calcarifer (Bloch)

Age-dependent susceptibility to nervous necrosis virus (NNV) was demonstrated for barramundi (Lates calcarifer). The experiment used juvenile barramundi produced from a single spawning that were challenged consecutively by immersion with a redspotted grouper nervous necrosis virus (RGNNV) isolate. The dose and environmental conditions (35 ppt salinity and 30 °C) were constant. Fish and water were sampled longitudinally for histopathology and RT-qPCR analysis to examine the evolution of the disease, virus replication, immune response and release of virus into water. Viral nervous necrosis (VNN) disease occurred in barramundi challenged at 3 and 4 weeks of age while fish challenged at 5, 7 and 9 weeks of age developed subclinical infection. Replication of NNV occurred faster and the concentration of virus reached higher concentrations in the younger fish with clinical disease. Virus isolation and qPCR tests indicated that infectious NNV was released from carcasses into water when fish were affected with clinical disease but not when NNV infection was subclinical. Based on these observations, we consider that carcasses from clinically infected fish have a potentially important role in the horizontal transmission of NNV, and barramundi juveniles should be protected from exposure to NNV until they are 5 weeks of age and reach the disease resistance threshold.

A mass resolved, high resolution neutral particle analyzer for C-2U

C-2U is a high-confinement, advanced beam driven field-reversed configuration plasma experiment which sustains the configuration for >5 ms, in excess of typical MHD and fast particle instability times, as well as fast particle slowing down times. Fast particle dynamics are critical to C-2U performance and several diagnostics have been deployed to characterize the fast particle population, including neutron and proton detectors. To increase our understanding of fast particle behavior and supplement existing diagnostics, an E ∥ B neutral particle analyzer was installed, which simultaneously measures H⁰ and D⁰ flux with large dynamic range and high energy resolution. Here we report the commissioning of the E ∥ B analyzer, confirm the instrument has energy resolution ΔE/E≲0.1 and a dynamic range E_max/E_min∼30, and present measurements of initial testing on C-2U.

The effects of iPod and text-messaging use on driver distraction: a bio-behavioral analysis

This study was designed to empirically examine the effects of iPod device and text-messaging activities on driver distraction. Sixty participants were asked to perform a driving simulation task while searching for songs using an iPod device or text messaging. Driving errors as measured by lane deviations were recorded and analyzed as a function of the distracters. Physiological measures (EEG) were also recorded during the driving phases in order to measure participant levels of cortical arousal. It was hypothesized that iPod use and text messaging would result in a profound effect on driving ability. The results showed a significant effect of iPod use and text-messaging on driving performance. Increased numbers of driving errors were recorded during the iPod and text-messaging phases than the pre- and post-allocation phases. Higher levels of Theta activity were also observed during the iPod and Text-messaging phase than the pre- and post-allocation phases. Implications for in-vehicle systems design, training, and safety are also discussed.

Acetabular changes associated with avascularnecrosis of the femoral head in a piglet model

Objectives

An experimental piglet model induces avascular necrosis (AVN) and deformation of the femoral head but its secondary effects on the developing acetabulum have not been studied. The aim of this study was to assess the development of secondary acetabular deformation following femoral head ischemia.

Methods

Intracapsular circumferential ligation at the base of the femoral neck and sectioning of the ligamentum teres were performed in three week old piglets. MRI was then used for qualitative and quantitative studies of the acetabula in operated and non-operated hips in eight piglets from 48 hours to eight weeks post-surgery. Specimen photographs and histological sections of the acetabula were done at the end of the study.

Results

The operated-side acetabula were wider, shallower and misshapen, with flattened labral edges. At eight weeks, increased acetabular cartilage thickness characterised the operated sides compared with non-operated sides (p < 0.001, ANOVA). The mean acetabular width on the operated side was increased (p = 0.015) while acetabular depth was decreased anteriorly (p = 0.007) and posteriorly (p = 0.44). The cartilage was thicker, with delayed acetabular bone formation, and showed increased vascularisation with fibrosis laterally and focal degenerative changes involving chondrocyte hypocellularity, chondrocyte cloning, peripheral pannus formation and surface fibrillation.

Conclusions

We demonstrate that femoral head AVN in the young growing piglet also induced, and was coupled with, secondary malformation in acetabular shape affecting both articular and adjacent pelvic cartilage structure, and acetabular bone. The femoral head model inducing AVN can also be applied to studies of acetabular maldevelopment, which is less well understood in terms of developing hip malformation.

Cite this article: Bone Joint Res 2014;3:130–8.

Evaluation of a nonthermal plasma needle to eliminate ex vivo biofilms in root canals of extracted human teeth

AIM

To evaluate the efficacy of a nonthermal plasma (NTP) at atmospheric pressure on ex vivo biofilm in root canals of extracted teeth.

METHODOLOGY

Intracanal contents from three teeth with root canal infections were collected, pooled and grown in thirty-five microCT-mapped root canals of extracted and instrumented human teeth. One group of teeth was treated with NTP, another with 6% NaOCl and one set was left untreated. The intracanal contents from twenty-seven teeth (nine teeth in each group) were plated on agar and colony forming units were determined. Parametric test of one-way analysis of variance (anova) was used to analyse statistical significance. The remaining teeth were cut open, stained with LIVE/DEAD(®) and examined with confocal laser scanning microscopy.

RESULTS

The untreated root canals were covered with biofilm of varying thickness. Treatment with nonthermal plasma decreased the number of viable bacteria in biofilms by one order of magnitude, whilst the NaOCl control achieved a reduction of more than four magnitudes. Both the NTP and the NaOCl treatment results were significantly different from the negative control (P < 0.05).

CONCLUSION

The nonthermal plasma displayed antimicrobial activity against endodontic biofilms in root canals, but was not as effective as the use of 6% NaOCl.

Diagnostic criteria for schwannomatosis

The neurofibromatoses are a diverse group of genetic conditions that share a predisposition to the development of tumors of the nerve sheath. Schwannomatosis is a recently recognized third major form of neurofibromatosis (NF) that causes multiple schwannomas without vestibular tumors diagnostic of NF2. Patients with schwannomatosis represent 2.4 to 5% of all patients requiring schwannoma resection and approximately one third of patients with schwannomatosis have anatomically localized disease with tumors limited to a single limb or segment of spine. Epidemiologic studies suggest that schwannomatosis is as common as NF2, but that familial occurrence is inexplicably rare. Patients with schwannomatosis overwhelmingly present with pain, and pain remains the primary clinical problem and indication for surgery. Diagnostic criteria for schwannomatosis are needed for both clinicians and researchers, but final diagnostic certainly will await the identification of the schwannomatosis locus itself.

Sensitivity of a clinical examination to predict need for radiography in children with ankle injuries: a prospective study

BACKGROUND

Radiographs are ordered routinely for children with ankle trauma. We assessed the predictive value of a clinical examination to identify a predefined group of low-risk injuries, management of which would not be affected by absence of a radiograph. We aimed to show that no more than 1% of children with low-risk examinations (signs restricted to the distal fibula) would have high-risk fractures (all fractures except avulsion, buckle, and non-displaced Salter-Harris I and II fractures of the distal fibula), and to compare the potential reduction in radiography in children with low-risk examinations with that obtained by application of the Ottawa ankle rules (OAR).

METHODS

Standard clinical examinations and subsequent radiographs were prospectively and independently evaluated in two tertiary-care paediatric emergency departments in North America. Eligible participants were healthy children aged 3-16 years with acute ankle injuries. Sample size, negative and positive predictive values, sensitivity, and specificity were calculated. McNemar's test was used to compare differences in the potential reduction in radiographs between the low-risk examination and the OAR.

FINDINGS

607 children were enrolled; 581 (95.7%) received follow-up. None of the 381 children with low-risk examinations had a high-risk fracture (negative predictive value 100% [95% CI 99.2-100]; sensitivity 100% [93.3-100]). Radiographs could be omitted in 62.8% of children with low-risk examinations, compared with only 12.0% reduction obtained by application of the OAR (p<0.0001).

INTERPRETATION

A low-risk clinical examination in children with ankle injuries identifies 100% of high-risk diagnoses and may result in greater reduction of radiographic referrals than the OAR.

Fast three-point dixon MR imaging using low-resolution images for phase correction: a comparison with chemical shift selective fat suppression for pediatric musculoskeletal imaging

OBJECTIVE

The purpose of this study is to describe and to implement a new fast three-point Dixon MR imaging sequence with online image reconstruction, and to compare this sequence with conventional chemical shift selective (CHESS) suppression of fat in pediatric musculoskeletal imaging.

SUBJECTS AND METHODS

A three-point Dixon technique using a fast spin-echo sequence with a new phase-correction algorithm providing online image reconstruction was implemented on a 1.5-T scanner. Twelve pediatric patients and young adults were imaged with both the new three-point Dixon and conventional CHESS sequences. Three radiologists un-aware of imaging parameters and clinical information independently scored the homogeneity of fat suppression and conspicuity of abnormality using a four-point system. An additional comparison between the two techniques was made using a phantom.

RESULTS

The three-point Dixon method showed superior fat suppression and lesion conspicuity (p < 0.001), particularly in the hands and feet, where CHESS is prone to inconsistent fat suppression. The phantom study showed no significant difference in the ratio of suppressed fat signal to background noise and more homogeneous fat suppression using the three-point Dixon method.

CONCLUSION

Compared with CHESS, the new fast three-point Dixon sequence with online image reconstruction provides superior fat suppression and lesion conspicuity and can be routinely used in pediatric musculoskeletal imaging.

Sub-ppt detection limits for copper ions with Gly-Gly-His modified electrodes

An electrochemical metal ion sensor has been developed with a detection limit of less than 0.2 ppt by the covalent attachment of the tripeptide Gly-Gly-His as a recognition element to a 3-mercaptopropionic acid modified gold electrode.

Aggressive multimodal treatment of pleuropulmonary blastoma

Pleuropulmonary blastoma is a rare intrathoracic neoplasm almost solely confined to childhood. Survival is poor. The authors report 2 children with extensive intrathoracic disease who are long term survivors after multimodal therapy. Both children received multiagent neoadjuvant chemotherapy, followed by surgical resection to remove all gross tumor. Postoperative chemotherapy was given to both children; radiotherapy was also given in the second case because of a question of positive tumor margins. Experience supports the use of multimodal therapy, including an aggressive surgical approach in the potentially curative treatment of this tumor.

Normal MR imaging anatomy of the ankle and foot in the pediatric population

MR imaging demonstrates the cartilaginous primordia of the bones of the foot and ankle. Ossification of the round bones begins in a single center and extends along the length of the bone. There is a difference between the orientation of the ossification center and that of the main cartilaginous structure. MR imaging can show the zones of the cartilage and the changes that precede ossification. The changes in the cartilage and marrow at different ages are illustrated for the ankle, hindfoot, and midfoot.

Imaging of sports injuries in children and adolescents

Imaging plays an important role in the diagnosis and management of sports injuries of childhood and adolescence. The injuries discussed are typical of those seen in the skeletally immature athlete. Imaging specialists must be able to apply the full range of imaging modalities when evaluating the injured young athlete.

Imaging of growth disturbance in children

Growth disturbance of the long bones in children is frequently post-traumatic but also occurs because of physeal, epiphyseal, or metaphyseal ischemia. The imaging features of growth arrest depend more on the anatomic site involved than on the cause. The physes of the distal tibia and femur and proximal tibia are disproportionately at risk because of their complex geometry. The central undulation in the distal femur and the bump in the anteromedial physis (Kump's bump) in the distal tibia are the sites of initial physiologic closure and the most frequent areas of premature fusion. The MR imaging features of growth disturbance are characteristic. T1-weighted images show low signal intensity GRL and variable signal intensity bony bridges. On GRE sequences, a bridge appears as low signal intensity interruption in the otherwise high signal intensity physeal cartilage. Physeal widening on GRE and T2-weighted images implies physeal dysfunction without bridge formation. Proton density and T2-weighted images best reveal associated metaphyseal and soft tissue changes. Regardless of the cause, MR imaging exquisitely depicts cartilaginous pathology at the physis. MR evaluation should be considered in patients at high risk for growth disturbance including young children with extensive residual growth potential; those with involvement of particularly vulnerable growth plates; and those with severe, complex fractures.

Protocol issues for delayed Gd(DTPA)(2-)-enhanced MRI (dGEMRIC) for clinical evaluation of articular cartilage

Biochemical and histologic data have validated the technique of delayed gadolinium-enhanced MRI, in which the T(1) values of cartilage after penetration of Gd(DTPA)2-allow assessment of the glycosaminoglycan (GAG) component of articular cartilage. This work describes the factors that have been found to be important for the practical implementation of the technique: 1) Exercise immediately after intravenous contrast administration was necessary for effective penetration of the contrast into the articular cartilage; 2) double-dose contrast was better than single-dose; 3) after contrast administration, a time window of 30-90 min for the hip, and 2-3 hr for all compartments of the knee proved to be appropriate for assessing articular cartilage; and 4) in some cases of hypointensities in the subchondral patellar bone, decreased penetration of the contrast agent into cartilage from bone was found. With the protocol described, ROIs on T(1) images were reproducible within 15% on two separate imaging sessions, and initial clinical studies demonstrated the possible applications of the technique. Magn Reson Med 45:36-41, 2001.

Protocol issues for delayed Gd(DTPA)(2-)-enhanced MRI (dGEMRIC) for clinical evaluation of articular cartilage

Biochemical and histologic data have validated the technique of delayed gadolinium-enhanced MRI, in which the T(1) values of cartilage after penetration of Gd(DTPA)2-allow assessment of the glycosaminoglycan (GAG) component of articular cartilage. This work describes the factors that have been found to be important for the practical implementation of the technique: 1) Exercise immediately after intravenous contrast administration was necessary for effective penetration of the contrast into the articular cartilage; 2) double-dose contrast was better than single-dose; 3) after contrast administration, a time window of 30-90 min for the hip, and 2-3 hr for all compartments of the knee proved to be appropriate for assessing articular cartilage; and 4) in some cases of hypointensities in the subchondral patellar bone, decreased penetration of the contrast agent into cartilage from bone was found. With the protocol described, ROIs on T(1) images were reproducible within 15% on two separate imaging sessions, and initial clinical studies demonstrated the possible applications of the technique. Magn Reson Med 45:36-41, 2001.

Cartilaginous path of physeal fracture-separations: evaluation with MR imaging--an experimental study with histologic correlation in rabbits

PURPOSE

To define the transverse levels of intracartilaginous fractures by using magnetic resonance (MR) imaging and histologic analysis in experimental physeal fracture-separations.

MATERIALS AND METHODS

Physeal fracture-separations were evaluated with MR imaging in 28 distal femurs and 28 proximal tibias of 22 immature rabbits. The intraphyseal transverse level of injury was graded as juxtaepiphyseal (germinal or proliferative zones) or juxtametaphyseal (hypertrophic zone or zone of provisional calcification). Histologic sections from 23 specimens were studied to assess correlations. We assessed nonenhanced and gadolinium-enhanced T1-weighted, intermediate-weighted, T2-weighted, and spoiled gradient-recalled-echo T1-weighted images.

RESULTS

In all MR studies, the injury was visible as a cleft of signal intensity lower than the signal intensity of the physeal cartilage. Juxtaepiphyseal extension, seen in 18 (64%) of 28 fractures, was more frequent in the undulating central part of the distal femoral physis than in the flatter proximal tibial physis (P =.008). In 20 of 23 specimens, MR imaging and histologic findings had excellent correlation for the detection of fracture level and morphology.

CONCLUSION

The course and level of injury within the cartilage in physeal fracture-separations can be defined with MR imaging. Extension into the juxtaepiphyseal physis, a potential risk factor for growth arrest, is detectable with MR imaging; MR imaging and histologic findings correlate well.

Intraosseus teratoma of the iliac bone

We present a 4-year-old child with a large iliac bone mass incidentally discovered in a plain abdominal radiograph. The pathological examination revealed a benign mature teratoma. To the best of our knowledge, the occurrence of intraosseous mature teratoma has not been previously reported. The child had had an immature teratoma of the neck discovered in a fetal ultrasound, and resected on day 6 of life. The neck teratoma recurred twice, at 16 months and at 3.5 years of age. In these two recurrences the lesion appeared progressively more mature. At the time of discovery of the iliac bone teratoma there was no evidence of residual neck disease. The radiological and pathological characteristics, differential diagnosis, and clinical course are discussed.

Normal maturation of the distal femoral epiphyseal cartilage: age-related changes at MR imaging

PURPOSE

To determine how signal intensity in the cartilaginous distal part of the femoral epiphysis varies with (a) age, (b) sex, and (c) distribution to the medial or lateral condyle on magnetic resonance (MR) images.

MATERIALS AND METHODS

Sixty-six sagittal T2-weighted or inversion-recovery MR images of the distal femoral epiphysis in children aged 2 months to 5 years 5 months were evaluated. Epiphyses were categorized into five types on the basis of progressive signal intensity changes within the epiphyseal cartilage along the weight-bearing region and posterior condyles. Epiphyseal type was compared with age, sex, and distribution of signal intensity changes within the condyle.

RESULTS

In early infancy, epiphyseal cartilage was homogeneous. During the 2nd year, signal intensity along the weight-bearing region decreased. With further advancing age, signal intensity in the posterior femoral condyles increased and became progressively more focal. The increase in epiphyseal grade correlated with age for both the medial and the lateral femoral condyles (r = 0.71 and r = 0.77, respectively; P < .001). There was no significant difference in epiphyseal changes between boys and girls or between medial and lateral condyles.

CONCLUSION

There is normal age-related variation in MR imaging signal intensity within the cartilaginous epiphysis of the distal femur. This may be related to weight bearing and epiphyseal maturation and should not be confused with disease.

Magnetic resonance imaging measurements of bone density and cross-sectional geometry

Magnetic resonance imaging (MRI) is commonly used in the assessment of the musculoskeletal system and associated pathology. The ability of MRI to measure the signals from water and lipid protons enables quantitative measurements of bone porosity. The goal of this investigation was to demonstrate that the density and cross-sectional geometry of whole bones can be noninvasively measured using MRI. Ten trabecular specimens cored from whale vertebrae were used to compare apparent bone density measured directly, and using a quantitative MRI algorithm. Bone density and several cross-sectional geometric properties were also measured using MRI in the distal tibia of 14 volunteers. The MRI measurements were compared with measurements made using quantitative-computed tomography (QCT). A proton density sequence was used for all MRI studies. A porosity phantom was included in the MRI examinations and used to convert the MRI signal intensity to bone volume fraction. Bone density and cross-sectional bone geometry were calculated from the bone volume fractions by assuming constant tissue properties. The apparent density of trabecular bone cores measured directly and using quantitative MRI were linearly related (r(2) = 0.959; P < 0. 01). A strong linear relation also existed between MRI and QCT measurements of ash density (r(2) = 0.923; P < 0.01) and cross-sectional geometric properties (r(2) = 0.976-0.992; P < 0.01). MRI data can be used to measure bone density and cross-sectional geometry of whole bones if a proton density sequence is used to homogenize differences in marrow composition and a porosity phantom is used for slice-specific volume fraction calibration.

Spin-Echo planar spectroscopic imaging for fast lipid characterization in bone marrow

Lipid characterization of bone marrow in vivo with proton magnetic resonance spectroscopy was performed using Spin-Echo Planar Spectroscopic Imaging sequences. The methods are shown capable of rapidly generating two-dimensional chemical shift imaging data sets suitable for measuring lipid indices that reflect unsaturation levels among triglycerides, as demonstrated in oil phantoms and bone marrow from a healthy volunteer. The volume coverage, spatial resolution, acquisition speed, and spectral characteristics of Spin-Echo Planar Spectroscopic Imaging should make it attractive for clinical studies of diseases affecting normal lipid chemical composition.

Rickets on MR images

BACKGROUND

The pathologic changes at the physis in patients with rickets have been well demonstrated histologically. Radiographs can depict only the associated osseous abnormalities.

PATIENTS AND METHODS

We report two children in whom MR imaging demonstrated rachitic changes in the physeal cartilage beyond the well-recognized bony features.

RESULTS

The striking appearance of the physes and the physes of the secondary ossification centers confirm that MR imaging can successfully evaluate the cartilaginous structures of the developing skeleton.

CONCLUSION

Though MR imaging is clearly unnecessary for the diagnosis of rickets, it is important that the typical features are not misinterpreted as other pathology.

Legg-Calvé-Perthes disease: MR imaging evaluation during manual positioning of the hip--comparison with conventional arthrography

PURPOSE

To evaluate the use of magnetic resonance (MR) imaging during manual positioning of the hip, or multipositional MR imaging, in an open-magnet configuration to study femoral head containment, articular congruency, and femoral head deformity in Legg-Calvé-Perthes disease.

MATERIALS AND METHODS

In 12 children with advanced Legg-Calvé-Perthes disease, multipositional MR imaging and conventional arthrography were compared in the assessment of containment, femoroacetabular congruency, and femoral head deformity. Images of the hips in several positions were compared subjectively and objectively.

RESULTS

MR imging correlated well with arthrography for overall subjective assessment of severity of disease (r = 0.71, P = .01), with good interobserver agreement (kappa = 0.65, P < .001). MR images demonstrated all cases of hinge abduction shown arthrographically. However, MR imaging failed to depict one case of femoral head flattening. MR imaging correlated well with arthrography in the objective evaluation of joint fluid and lateral subluxation (r = 0.80, P < .01). MR imaging correlated poorly with arthrography in the measurement of sphericity of the femoral head.

CONCLUSION

Multipositional MR imaging with an open-magnet configuration was comparable to arthrography for demonstration of femoral head containment and congruency of the articular surfaces of the hip. In the evaluation of deformity, it performed less well.

Radiographic appearance of the normal distal tibiofibular syndesmosis in children

In adults, a tibiofibular clear space (i.e., distance from the incisura fibularis to the medial fibula) of > or = 6 mm or a loss of tibiofibular overlap has been reported to correlate with injury to the distal tibiofibular syndesmosis. We reviewed anteroposterior (AP), lateral, and mortise ankle radiographs from 106 children (50 boys, 56 girls) aged 1-15 years in an attempt to assess whether these criteria are applicable to children. The incisura was detectable at a mean age of 8.2 years for girls and 11.2 years for boys. The range of tibiofibular clear space among the 48 children with a detectable incisura was 2-8 mm; seven (23%) of these 48 children had a clear space of > or = 6 mm in one or more views. The mean age at which the tibiofibular overlap began to appear on the AP view was 5 years for both genders, whereas on the mortise view, it was 10 years for girls and 16 years for boys. The criteria used to evaluate the integrity of the distal tibiofibular syndesmosis in adults do not apply to children in this normal study population.

Growth cartilage: normal appearance, variants and abnormalities

The cartilaginous structures in the growing ends of the bone have a complex anatomy. MR imaging allows exquisite depiction of these structures. The normal anatomy and biochemical features of the zones of cartilage are reviewed. Based on an analysis of signal characteristics, it is possible to optimize the use of pulse sequences to study the normal structures and abnormalities of growing bone.

Musculoskeletal trauma in children

MR imaging has facilitated the study of pediatric injuries by demonstrating the extraosseous and cartilaginous component of these lesions. In injuries to the epiphysis and physis, osteochondral injuries and avulsion injuries, the cartilaginous component is usually the most important part of the lesion. Stress fractures and other injuries to the marrow also can be demonstrated with MR imaging. In the context of musculoskeletal injuries in children, MR imaging is most valuable in demonstrating the extent of injuries to radiographically occult areas.

Hip arthrography, aspiration, block, and bursography

Hip arthrography in children with Legg-Calvé-Perthes disease is used to determine the optimal position of the femoral head for immobilization during the process of epiphyseal healing and in developmental dysplasia of the hip as a guide to operative treatment. In adult hips, arthrography and aspiration are useful techniques for demonstration of prosthetic implant loosening and infection. Aspiration of the hip joint and culture of aspirated fluid helps to diagnose septic arthritis. Anesthetic hip arthrography helps to distinguish between pain originating from the hip and radicular pain from the spine. Iliopsoas bursography may be used to diagnose bursal enlargement and its cause.

Glenohumeral deformity secondary to brachial plexus birth palsy

Ninety-four patients who had brachial plexus birth palsy were entered into a prospective study to evaluate the association between persistent palsy, age-related musculoskeletal deformity, and functional limitations. Of these patients, forty-two had either computerized tomography or magnetic resonance imaging to assess the presence and degree of incongruity of the glenohumeral joint, deformity of the humeral head, and hypoplasia of the glenoid as part of the preoperative planning for a reconstructive operation. Functional ability was rated with use of the classification of Mallet, on a scale of 1 to 5. The mean glenoscapular angle (the degree of retroversion of the glenoid) on the affected side was -25.7 degrees compared with -5.5 degrees on the unaffected side. Twenty-six (62 per cent) of the forty-two shoulders had evidence of posterior subluxation of the humeral head, with a mean of only 25 per cent (range, 0 to 50 per cent) of the head being intersected by the scapular line. Progressive deformity was found with increasing age (p < 0.001). The natural history of untreated brachial plexus birth palsy with residual weakness is progressive glenohumeral deformity due to persistent muscle imbalance. The status of the glenohumeral joint must be addressed when the choice between tendon transfer and humeral derotation osteotomy for reconstruction of the shoulder is considered for these patients.

Developing epiphysis: MR imaging characteristics and histologic correlation in the newborn lamb

PURPOSE

To correlate magnetic resonance (MR) signal characteristics of developing regions at the ends of bones with the histologic findings.

MATERIALS AND METHODS

In 36 newborn lamb epiphyses (including cartilage of the epiphysis and physis, and bone of the secondary ossification center and juxtaphyseal metaphysis), signal intensity and thickness of cartilaginous regions seen on MR images were correlated with architecture and thickness of zones shown in corresponding histologic sections. Possible effects of T2, magnetization transfer, fat or water content, chemical shift, and anisotropy on differences in regional signal intensity were evaluated.

RESULTS

MR imaging depicted five regions between the secondary ossification center and the metaphysis corresponding histologically to (a) zone of provisional calcification of the secondary ossification center, (b) physis of the secondary ossification center, (c) epiphyseal cartilage, (d) physis, and (e) zone of provisional calcification. The thickness of regions shown on T1- and T2-weighted images correlated with that of histologic zones (r = .9). T2 signal intensity and relaxation time were greater in physeal than in epiphyseal cartilage (P < .01). No regional differences due to fat or water content, magnetization transfer, chemical shift, or anisotropy were found.

CONCLUSION

MR imaging findings differentiate epiphyseal and physeal regions and correlate with histologic findings. T2 is slower in physeal than in epiphyseal cartilage, probably reflecting differences in water binding.

Gadolinium-enhanced MR imaging of pediatric patients after reduction of dysplastic hips: assessment of femoral head position, factors impeding reduction, and femoral head ischemia

OBJECTIVE

We describe gadolinium-enhanced MR imaging of position and vascular enhancement of the femoral head in pediatric patients who have undergone reduction of hip dislocation.

SUBJECTS AND METHODS

Within 24 hr of hip reduction and spica casting, we performed 25 gadolinium-enhanced MR studies in 18 infants and young children (15 girls, three boys) with 23 dysplastic hips. All but two patients underwent closed reductions. We evaluated intraoperative arthrograms for obstacles to reduction and subsequent radiographs for avascular necrosis.

RESULTS

MR images showed that all femoral heads were in their respective acetabula, but several structures interfered with concentric reduction. Obstacles to reduction included a pulvinar (n = 16), infolding of the capsule (n = 9), interposition of the labrum (n = 2), and a hypertrophied ligamentum teres and transverse ligament (n = 2). All 50 femoral heads showed enhancement: 35 normally, 10 homogeneously but less than on the contralateral femoral head or the ipsilateral greater trochanter, and five with areas of focally decreased enhancement. Hips that showed decreased enhancement had undergone greater degrees of abduction (r = .38, p < .01).

CONCLUSION

Gadolinium-enhanced MR imaging can reveal abnormalities of hip position and proximal femoral epiphyseal and physeal vascularity that can occur after hip reduction. Abnormalities of enhancement were more frequent in patients who had greater femoral abduction. The effect of decreased epiphyseal vascular enhancement is still uncertain.

Glenohumeral deformity secondary to brachial plexus birth palsy

Ninety-four patients who had brachial plexus birth palsy were entered into a prospective study to evaluate the association between persistent palsy, age-related musculoskeletal deformity, and functional limitations. Of these patients, forty-two had either computerized tomography or magnetic resonance imaging to assess the presence and degree of incongruity of the glenohumeral joint, deformity of the humeral head, and hypoplasia of the glenoid as part of the preoperative planning for a reconstructive operation. Functional ability was rated with use of the classification of Mallet, on a scale of 1 to 5. The mean glenoscapular angle (the degree of retroversion of the glenoid) on the affected side was -25.7 degrees compared with -5.5 degrees on the unaffected side. Twenty-six (62 per cent) of the forty-two shoulders had evidence of posterior subluxation of the humeral head, with a mean of only 25 per cent (range, 0 to 50 per cent) of the head being intersected by the scapular line. Progressive deformity was found with increasing age (p < 0.001). The natural history of untreated brachial plexus birth palsy with residual weakness is progressive glenohumeral deformity due to persistent muscle imbalance. The status of the glenohumeral joint must be addressed when the choice between tendon transfer and humeral derotation osteotomy for reconstruction of the shoulder is considered for these patients.

In vivo bone marrow lipid characterization with line scan Carr-Purcell-Meiboom-Gill proton spectroscopic imaging

Line scan Carr-Purcell-Meiboom-Gill spectroscopic imaging sequences have been used to extract lipid chemical composition indices in healthy adult bone marrow in the knee at 1.5 T. Since several spectroscopic echo readouts follow each excitation, the information acquired reflects a balance between spectral T2 decay processes and spectral resolution. To examine this balance in detail, data sets with two different echo spacings and spectral resolutions have been acquired to compare the information available from each in studies of bone marrow. Oils for which high field (7 T) proton spectra were recorded were used to evaluate the accuracy of lipid chemical composition indices extracted from the line scan Carr-Purcell-Meiboom-Gill spectroscopic imaging methods at 1.5 T. The extension of the method to fast spectroscopic imaging of bone marrow with multiple echoes is demonstrated.

Chronic physeal fractures in myelodysplasia: magnetic resonance analysis, histologic description, treatment, and outcome

Thirteen myelodysplastic children with 19 chronic physeal fractures were treated. All were treated with prolonged immobilization (average, 5.8 months; range, 3-18 months) in either braces or casts; four of the fractures required operative fixation to facilitate healing. All were healed at 4.8-years follow-up but, in four of the fractures, the growth plate closed prematurely. Three of the children underwent magnetic resonance imaging (MRI) of the injured physes, and one underwent physeal biopsy as part of her operative epiphysiodesis. Histologic analysis revealed three distinct zones of physeal pathoanatomy: a normal zone of proliferation; a thickened, disorganized zone of hypertrophy; and a vascularized zone of fibrous tissue adjacent to the metaphysis. On MRI, there was thickening of the physis and irregularity of the zone of provisional calcification. The physeal cartilage and the juxtametaphyseal fibrovascular tissue enhanced with gadolinium. These findings corroborate earlier mechanistic proposals for physeal injury in myelodysplasia: chronic stress or trauma to the poorly sensate limb produces micromotion at the zone of hypertrophy, yielding a widened, disorganized physis, and leading to fracture, displacement, and delayed union.

Postreduction computed tomography in developmental dislocation of the hip: part I: analysis of measurement reliability

Twenty computed tomographic (CT) scans of infants in spica casts after closed or open reduction for developmental hip dislocation (DDH) were analyzed for intra- and interrater reliability. Ten measurements of infant hip anatomy were assessed by three raters by using standard statistical analysis. All six measurements of acetabular anteversion and lateral or posterior displacement of the femoral metaphysis from the acetabulum or from a modified Shenton's line drawn from the pubic rami demonstrated both intra- and interrater reliability. All four measurements of acetabular structure could not be reliably measured either within or between observers. We also introduced a new measurement based on the principle of Shenton's line to aid in the assessment of femoral-head location after reduction in patients with DDH; this was reliably determined both within and among observers.

MRI demonstration of occult purely chondral fractures of the tibia: a potential mimic of meniscal tears

We report the case of a 12-year-old boy with bilateral, purely chondral fractures of the tibia. The patient had Crohn's disease treated with systemic corticosteroids. MR images of the knee were initially interpreted to show a bucket-handle tear of the lateral meniscus. However, arthroscopic evaluation revealed purely chondral fractures of the tibial plateau without meniscal damage. Re-evaluation of the MR study identified the chondral fracture of the lateral tibial articular cartilage detected arthroscopically. This purely chondral fracture of the tibial plateau represented a rare finding in the symptomatic knee that mimicked a meniscal tear by history, physical exam, and MR imaging.

Postreduction computed tomography in developmental dislocation of the hip: part II: predictive value for outcome

Computed tomographic (CT) scans were performed after closed reduction of 68 dislocated hips in 53 infants in spica casts with developmental hip dislocation (DDH). Ten measurements were made on the CT scans including acetabular indices and anteversion, hip-abduction angle, lateral and posterior displacement of the femur from the acetabulum, and femoral displacement from a modified Shenton's line drawn from the pubic rami. By using analysis of variance, the correlation of each variable with outcome after reduction was determined, including the development of avascular necrosis or the need for further surgery because of residual dysplasia. None of the variables was predictive of the outcome of persistent hip dysplasia. The subsequent development of avascular necrosis was statistically associated with hip-abduction angles >55 degrees as measured on postreduction CT scans, with 20% of the involved hips developing avascular necrosis on subsequent follow-up.