236. The Comparative Utility Of Metagenomic Next-Generation Sequencing and Universal PCR for Pathogen Detection on Cerebrospinal Fluid: A Retrospective Analysis From a Tertiary Care Center

Background

Many neurologic syndromes are underpinned by infectious etiologies that are difficult to diagnose. Broad-range, universal PCR (uPCR), and metagenomic next-generation sequencing (mNGS) are emerging molecular techniques that may allow for enhanced pathogen detection in challenging cases. To date, their comparative clinical utility for pathogen detection in cerebrospinal fluid (CSF) has not been described.

Methods

We searched the electronic medical record at University of California, San Francisco for all patients who had mNGS and uPCR results available from the same CSF specimen. Using all available clinical information, patients’ clinical episodes were categorized into one of four categories: (1) confirmed central nervous system (CNS) infection, (2) likely CNS infection, (3) confirmed/likely noninfectious etiology, (4) unknown etiology. We also determined whether mNGS and/or uPCR results changed clinical management.

Results

We identified 75 patients with 78 paired mNGS and uPCR results on CSF. 14/78 (17.9%) had a confirmed CNS infection underpinning their clinical presentation, 11 (14.1%) had a likely CNS infection, 33 (42.3%) had a likely noninfectious cause, and 20 (25.6%) had etiologies that could not be determined. Of the 14 patients with confirmed CNS infection, n = 4 (28.6%) were diagnosed by mNGS and n = 1 (7.1%) by uPCR (Table 1). Most diagnoses missed by mNGS and uPCR were made by CSF serology or from sites other than CSF. Overall, mNGS detected a pathogen in n = 10/78 (12.8%) cases, compared with n = 4/78 (5.1%) using uPCR (Table 2). Among those with a positive mNGS result, n = 6/10 represented a true or likely true positive result, while the remaining were likely contaminants. Of those with a positive uPCR result, n = 1/4 represented a true positive result, while n = 3/4 were likely contaminants. Clinical management was changed by the mNGS or uPCR result in two cases (Table 2).

Conclusion

mNGS appears to have superior clinical utility to that of universal PCR for pathogen detection in CSF samples, in large part because of additional ability to detect DNA and RNA viruses. Further studies are required to determine the clinical contexts in which mNGS is likely to have maximal diagnostic yield and to better define the utility of uPCR for CNS infections.

Disclosures

All authors: No reported disclosures.

T3 Induces Both Markers of Maturation and Aging in Pancreatic β-Cells

Previously, we showed that thyroid hormone (TH) triiodothyronine (T₃) enhanced β-cell functional maturation through induction of Mafa High levels of T₃ have been linked to decreased life span in mammals and low levels to lengthened life span, suggesting a relationship between TH and aging. Here, we show that T₃ increased p16^Ink4a (a β-cell senescence marker and effector) mRNA in rodent and human β-cells. The kinetics of Mafa and p16^Ink4a induction suggested both genes as targets of TH via TH receptors (THRs) binding to specific response elements. Using specific agonists CO23 and GC1, we showed that p16^Ink4a expression was controlled by THRA and Mafa by THRB. Using chromatin immunoprecipitation and a transient transfection yielding biotinylated THRB1 or THRA isoforms to achieve specificity, we determined that THRA isoform bound to p16^Ink4a , whereas THRB1 bound to Mafa but not to p16^Ink4a On a cellular level, T₃ treatment accelerated cell senescence as shown by increased number of β-cells with acidic β-galactosidase activity. Our data show that T₃ can simultaneously induce both maturation (Mafa) and aging (p16^Ink4a ) effectors and that these dichotomous effects are mediated through different THR isoforms. These findings may be important for further improving stem cell differentiation protocols to produce functional β-cells for replacement therapies in diabetes.

[MRI for monitoring of high intensity focused ultrasound: current developments]

With respect to monitoring of high intensity focused ultrasound (HIFU), synonym focused ultrasound (FUS) treatment, magnetic resonance imaging (MRI) is characterized by several advantageous properties: the precise definition and morphological characterization of the target area (before and after the intervention), the real-time visualization of the treatment effect by thermal imaging (during the intervention) and in the sense of a stereotactic system, the 3-dimensional localization of the target lesion, planning of the target volume and assessment of the achieved ablation volume (before and during the intervention). Non-enhanced T2-weighted multislice MR images are acquired for planning of the intervention. For temperature monitoring (comprising thermometry and thermodosimetry), the temperature-dependent shift of proton resonance frequency (PRFS) is most frequently employed. This method is independent of the treated tissue type or thermally induced tissue changes and facilitates a relative measurement of the temperature change based on a reference value. Future MRI applications include diffusion-weighted MRI (DWI-MRI; for the intrainterventional estimation of treatment efficacy), dynamic contrast-enhanced MRI (DCE-MRI, for the prediction of the potential and assessment of the treatment effect achieved) and motion-corrected temperature monitoring (referenceless and multibaseline thermometry).

Interdisciplinary expert consultation via a teleradiology platform--influence on therapeutic decision-making and patient referral rates to an academic tertiary care center

In addition to teleradiological reporting as a nighthawking or a regular service, teleradiological communication can be used for interdisciplinary expert consultation. We intended to evaluate an interdisciplinary consultation system based on a teleradiology platform with regard to its impact on therapeutic decision-making, directed patient referrals to an academic tertiary care center and the economic benefit for the hospital providing the service. Therefore, consultations from five secondary care centers and consecutive admissions to an academic tertiary care center were prospectively evaluated over a time period of six months. A total of 69 interdisciplinary expert consultations were performed. In 54 % of the cases the patients were consecutively referred to the university hospital for further treatment. In all acutely life-threatening emergencies (n = 9), fast and focused treatment by referral to the academic tertiary care center was achieved (average time to treat 130 min). The admissions to the academic tertiary care center led to improved utilization of its facilities with additional revenue of more than 1,000000 euro p. a. An interdisciplinary expert consultation via a teleradiology platform enables fast and efficient expert care with improved and accelerated patient management and improved utilization of the service providing hospital.

[University clinics as centers of radiologic performance alliances in the ambulatory and inpatient sector]

PROBLEM

Health care delivery in Germany has to face severe challenges that will lead to a closer integration of services for in- and out-patients. University hospitals play an important role due to their activities in research, education and health care delivery. They are requested to promote and evaluate new means and ways for health care delivery.

METHODS

The Institute of Clinical Radiology at the University Hospital of the Ludwig-Maximilians-University started teleradiological services for hospitals and general practices in January 1999 in the framework of the "Imaging services--teleradiological center of excellence". Legal, technical and organizational prerequisites were analyzed.

RESULTS

Networks between university hospitals and general practices are not likely to solve all future problems. They will, however, increase the availability of the knowledge of experts even in rural areas and contribute to a quality ensured health care at the patients home. Future developments may lead to international co-operations and such services may be available to patients abroad.

CONCLUSION

Legal, technical and organizational obstacles have to be overcome to create a framework for high quality telemedical applications. University hospitals will play an important role in promoting and evaluating teleradiological services.

[Time needs in evaluating digital thoracic images on the monitor in comparison with alternator]

PURPOSE

Evaluation of time efficiency in softcopy reading versus hardcopy reading of digital chest x-rays.

MATERIAL AND METHODS

130 normal and pathologic chest x-rays in two plains were analyzed by 4 experienced radiologist at both a digital workstation and the light box. Reading time and switch time between two patient folders were measured as well as the frequency of post-processing at the monitor.

RESULTS

Reading time at the workstation slightly exceeded reading time at the light box; differences were not statistically significant. Post-processing (frequency between 2% and 83%) did not significantly prolong reading time. Mean switch time between two patient folders was 4.3 sec at the workstation and 13.7 sec at the light box.

CONCLUSION

As compared to hardcopy reading, softcopy reading of digital chest x-rays does not significantly increase reading time. Switch time between patient folders can be reduced at the workstation by a factor of two to four.

[Reconstruction methods in postprocessing of CT- and MR-angiography of the aorta]

The aim of the study was to investigate the use of 2D and 3D reconstructions in examinations of the aorta with CT and MRI. Postprocessing of 5 data sets including 2D MPR reconstructions, 3D MIP reconstructions and 3D volume rendering reconstructions acquired with contrast enhanced CTA and 5 data sets acquired with contrast enhanced MRA were performed. The luminal diameter, the length of the aneurysm and the detection of dissection was assessed for the reconstructions and the source images. Aneurysms and dissections of the aorta were correctly identified on source images. 2D MPR reconstructions and source images allow for a clear and easy image analysis including cases with high signal intensity or density of surrounding tissue and complex anatomical structures. The diameter and length of pathological findings can be determined correctly wit 2D MPR reconstructions, even when the vessel orientation is not exactly inplane or throughplane in relation to the source images. MIP reconstructions are suitable for contrast enhanced MRA data sets with high C/N ratio and volume rendering reconstructions are suitable for contrast enhanced CTA data sets, where calcifications and bone have also high density. For 3D visualization of large volumes MIP reconstructions are the method of choice for MRA and volume rendering reconstructions for CTA, respectively. In addition, 2D MPR can be necessary to determine the diameter and length of pathological findings.

[Chronic infections of the skeletal system. Their imaging diagnosis]

The diagnosis of chronic osteomyelitis is made on the basis of clinical, radiologic and histologic findings. The role of imaging in patients with known chronic osteomyelitis is to detect and to delineate areas of active infection. To correctly interpret the imaging findings, it is essential to take both the individual clinical findings and previous imaging studies into account. Reliable signs of active infection are bone marrow abscess, sequestra and sinus tract formation. Only the combined evaluation of bony changes together with alterations of the adjacent soft tissues provides good diagnostic accuracy. Projection radiography gives an overview of the condition of the bone, which provides the basis for follow-up and the selection of further imaging modalities. Computed tomography can be used to evaluate even discrete or complex bony alterations and to guide percutaneous biopsy or drainage. Magnetic resonance imaging achieves the best diagnostic sensitivity and specificity and provides superior contrast as well as anatomical resolution in both bone marrow and soft tissues. In this paper the features and clinical relevance of imaging in primary chronic osteomyelitis, posttraumatic osteomyelitis, tuberculous spondylitis and osteomyelitis of the diabetic foot are reviewed, with particular respect to MRI.

Partial rupture of the distal biceps tendon

Partial rupture of the distal biceps tendon is a relatively rare event, and various degrees of partial tendon tears have been reported. In the current study four patients with partial atraumatic distal biceps tendon tears (mean age, 59 years; range, 40-82 years) are reported. In all four patients, a common clinical pattern emerged. Pain at the insertion of the distal biceps tendon in the radius unrelated to any traumatic event was the main symptom. In all patients the diagnosis was based on magnetic resonance imaging or computed tomography imaging. In three of four patients the partial rupture of the tendon caused a significant bursalike lesion. The typical appearance was a partially ruptured biceps tendon, with contrast enhancement signaling the degree of degeneration, tenosynovitis, and soft tissue swelling extending along the tendon semicircular to the proximal radius. In three patients, conservative treatment was successful. Only one patient needed surgery, with reinsertion of the tendon resulting in total functional recovery.

[Spondylolysis in the developmental stage: diagnostic contribution of MRI]

PURPOSE

To assess the value of MR imaging in demonstrating ongoing spondylolysis in adolescents.

METHODS

MRI was performed in 9 juvenile patients (3 female, 6 male aged 8-16 years; mean 12.5 y) with pain during hyperextension. In 6 patients a CT scan and in 5 a plain film was available.

RESULTS

In all patients bone marrow edema was found in the pars interarticularis and the pedicle, which was bilateral in 4 patients. In 7/9 cases the L5 vertebra was affected, in 2/9 cases spondylolysis was found in L4. In 3 cases the edema reached the middle third of the vertebral body and a tumor was suspected. In all CT scans a bilateral incomplete or complete cleft in the pars inter-articularis was found. In 4/6 CT-scans a sclerosis was seen in the area of the bone marrow edema. Only in 1/5 plain films was there a suspicion for a spondylolysis, four examinations were completely normal.

CONCLUSIONS

To eliminate underlying causal conditions of spondylolysis and to install specific therapy, early diagnosis is mandatory. MR imaging should be the first and only imaging modality in young patients with low back pain during and after exercise and pain with hyperextension. Bone scans and CT scans should be avoided due to irradiation, plain films usually do not reveal pathological findings in developing sponylolysis.

[Filmless documentation and image distribution to referring physicians exemplified by a radiologic community practice]

In healthcare, cost effectiveness as well as the quality of examinations and procedures are subjected to quickly increasing expectations and demands: we like to demonstrate how the resulting challenges and problems can be met with implementation of modern information technology. Analysing the respective demands (pattern of quantities) and choosing the adequate technical solution/technical approach, we found filmless reading and the usage of digital image distribution to communicate with referring physicians to be cost effective as well as of higher quality. Special attention should be paid to the rigorous maintenance of data security and access. Today's information technology allows individual adjustment to the respective size and requirements of a radiological department or practice for filmless reading and digital image distribution. Working with the systems as a matter of routine and using all of the expanding technological possibilities, an important improvement of service and quality can be achieved. Amortisation will be obtained despite high investments, due to the subsequent savings in personal- and enterprise costs.

Usefulness of morphological characteristics for the differentiation of benign from malignant solitary pulmonary lesions using HRCT

The aim of this study was to analyze different characteristics on high-resolution computed tomography (HRCT) that help differentiate benign solitary pulmonary lesions (BSPLs) from malignant solitary pulmonary lesions (MSPLs). High-resolution computed tomography was performed on 104 consecutive patients with SPLs. The whole lesion was examined with a slice thickness of 1 mm and a 12-cm field of view. All lesions were surgically excised within 24 h of the CT examination. Satellite nodules, cavitations, and necrosis were found only in MSPLs. Useful characteristics for the differentiation of BSPLs from MSPLs were the presence of spicules (p < 0.00005), spicules extending to the visceral pleura (p < 0.0005), the vessel sign (p < 0.0005), pleural retraction (p < 0.001), circumscribed pleural thickening (p < 0.001), the bronchus sign (p < 0.005), the presence of ground-glass attenuation adjacent to the SPL (p < 0.01), the density of the lesion (p < 0.05), and the length of spicules (p < 0.05). Using the significant characteristics p < 0.01 for the identification of MSPLs, a sensitivity of 91.4 % and a specificity of 56.5 % (accuracy of 83.7 %) was found. A precise morphological assessment of the periphery of the pulmonary lesion is necessary. The HRCT technique is useful in differentiation of BSPLs from MSPLs. However, metastases strongly resembled benign lesions in terms of size and edge type, and chronic inflammatory pseudotumors as a group mimic MSPLs.

Hospitalized children of substance-abusing parents and physically and sexually abused children: a comparison

The symptoms and diagnoses of 58 psychiatrically hospitalized children aged 12 or under who were children of substance abusing parents (COSAPs) were compared with a matched group of 51 children who were not COSAPs. These two groups were further subdivided according to history or lack of history of physical and/or sexual abuse. Symptoms and diagnoses of COSAPs and physically and/or sexually abused (P/SAs) children differed significantly from the hospitalized group who were neither COSAPs nor P/SAs. Being a COSAP and/or P/SA are strong correlates of psychiatric hospitalization for the children studied. Both high-risk groups should be awarded special diagnostic and treatment consideration that would include their systematic identification and focused treatment.