Magnetic Resonance Imaging Findings of Early Spondylodiscitis: Interpretive Challenges and Atypical Findings

Lung adenocarcinoma presenting as miliary lung metastasis on imaging

Intrapulmonary miliary metastasis is a rare presentation of adenocarcinoma of the lung, characterized by the dissemination of cancer cells throughout the lung parenchyma in different patterns. This case report highlights an unusual presentation of adenocarcinoma of the lung with intrapulmonary miliary metastasis, emphasizing the diagnostic challenges and management considerations. Here, we report a case of a 51-year-old female who presented to the emergency department (ED) with a 2-month history of dry cough, which started after a flu illness and was associated with mild shortness of breath, left-sided chest pain, and miliary nodules on chest imaging. During bronchoscopy, a transbronchial biopsy was taken for further pathological assessment. The results showed histopathological evidence of lung adenocarcinoma.

Imaging assessment of spine infection

This article comprehensively reviews current imaging concepts in spinal infection with primary focus on infectious spondylodiscitis (IS) as well as the less common entity of facet joint septic arthritis (FSA). This review encompasses the multimodality imaging appearances (radiographs, CT, MRI, and nuclear imaging) of spinal infection-both at initial presentation and during treatment-to aid the radiologist in guiding diagnosis and successful management. We discuss the pathophysiology of spinal infection in various patient populations (including the non-instrumented and postoperative spine) as well as the role of imaging-guided biopsy. We also highlight several non-infectious entities that can mimic IS (both clinically and radiologically) that should be considered during image interpretation to avoid misdiagnosis. These potential mimics include the following: Modic type 1 degenerative changes, acute Schmorl's node, neuropathic spondyloarthropathy, radiation osteitis, and inflammatory spondyloarthropathy (SAPHO syndrome).

Diagnosis and management of infections related to spinal pain interventions

Although relatively rare, infections related to spinal pain interventions pose significant risks with an increase in the frequency of these procedures. This review investigates the incidence, risk factors, and management of infections following spinal pain interventions, such as epidural steroid injections, nucleoplasty, and facet joint injections. Most of the existing literature comprises case reports and retrospective studies with limited prospective research, owing to the nature of these infections. Our analysis revealed that while the overall infection rate is low, potential complications, such as epidural abscesses and spondylodiscitis, can be severe and life-threatening. The risk factors include advanced age, diabetes, immunosuppression, and multiple spinal procedures. Early diagnosis and timely intervention are critical to prevent long-term morbidity. These findings emphasize the importance of developing standardized diagnostic algorithms and treatment guidelines to support clinicians in managing these infections effectively. Future research should focus on large-scale studies to understand the impact of these infections better and refine clinical management strategies.

Imaging review of the atypical spinal epidural space pathologies

Pathologies affecting the spinal epidural space (SES) comprise various abnormalities. However, they all have the potential to cause thecal sac narrowing or spinal cord compression. In this review, we group these pathologies into degenerative, infective, neoplastic, vascular, traumatic, and others, focusing on their imaging features. Degenerative pathologies of the SES range from disc to facet disease, with a particular emphasis on the less common degenerative pathologies in this review. Infective pathologies affecting the epidural space include spondylodiscitis and associated epidural phlegmon and abscess. Neoplasms arising from typical SES components include neurofibroma, hemangioma, and liposarcoma. MRI is the best modality to assess the anatomy and abnormalities of the epidural space. MRI, combined with computed tomography, or a radiograph, is useful for the evaluation of bones or radiopaque foreign bodies.

Society of skeletal radiology position paper - recommendations for contrast use in musculoskeletal MRI: when is non-contrast imaging enough?

The following White Paper will discuss the appropriateness of gadolinium administration in MRI for musculoskeletal indications. Musculoskeletal radiologists should consider the potential risks involved and practice the judicious use of intravenous contrast, restricting administration to cases where there is demonstrable added value. Specific nuances of when contrast is or is not recommended are discussed in detail and listed in table format. Briefly, contrast is recommended for bone and soft tissue lesions. For infection, contrast is reserved for chronic or complex cases. In rheumatology, contrast is recommended for early detection but not for advanced arthritis. Contrast is not recommended for sports injuries, routine MRI neurography, implants/hardware, or spine imaging, but is helpful in complex and post-operative cases.

Diagnostic performance of metagenomic next-generation sequencing and conventional microbial culture for spinal infection: a retrospective comparative study

PURPOSE

The study evaluated the diagnostic performance of metagenomic next-generation sequencing (mNGS) as a diagnostic test for biopsy samples from patients with suspected spinal infection (SI) and compared the diagnostic performance of mNGS with that of microbial culture.

METHODS

All patients diagnosed with clinical suspicion of SI were enrolled, and data were collected through a retrospective chart review of patient records. Biopsy specimens obtained from each patient were tested via mNGS and microbial culture. Samples were enriched for microbial DNA using the universal DNA extraction kit, whole-genome amplified, and sequenced using MGISEQ-200 instrument. After Low-quality reads removed, the remaining sequences for microbial content were analyzed and aligned using SNAP and kraken2 tools.

RESULTS

A total of 39 patients (19 men and 20 women) were deemed suitable for enrollment. The detection rate for pathogens of mNGS was 71.8% (28/39), which was significantly higher than that of microbial culture (23.1%, p = 0.016). Mycobacterium tuberculosis complex was the most frequently isolated. Using pathologic test as the standard reference for SI, thirty-one cases were classified as infected, and eight cases were considered aseptic. The sensitivity and specificity values for detecting pathogens with mNGS were 87.1% and 87.5%, while these rates were 25.8% and 87.5% with conventional culture. mNGS was able to detect 88.9% (8/9) of pathogens identified by conventional culture, with a genus-level sensitivity of 100% (8/8) and a species-level sensitivity of 87.5% (7/8).

CONCLUSION

The present work suggests that mNGS might be superior to microbial culture for detecting SI pathogens.

Unmasking the great imitators-noninfectious conditions masquerading as spinal tuberculosis in a developing country: A single-center case series analysis

Background

The diagnosis of spinal tuberculosis often relies on clinical, radiological, and laboratory findings, particularly in resource-constrained settings. However, numerous noninfectious conditions exhibit similar clinical and radiological features to spinal tuberculosis, leading to potential misdiagnosis in the absence of microbiological or histopathological confirmation. This study aims to present a case series from a developing country, highlighting noninfectious conditions that mimic spinal tuberculosis.

Methods

A retrospective analysis was conducted on hospital records and imaging of patients diagnosed with spinal tuberculosis, lacking microbiological or histopathological evidence, and unresponsive to empirical antitubercular treatment. Patients displaying noninfectious conditions resembling spinal tuberculosis upon further investigation were included. Clinical and radiological findings of these patients were thoroughly analyzed.

Results

Among a total of 23 patients observed over a 6-year period (2015-2020), various noninfectious conditions were identified as mimickers of spinal tuberculosis. These conditions included vertebral body haemangioma, ankylosing spondylitis (with or without Andersson lesion), rheumatoid pannus, osteoid osteoma, cystic hygroma, multiple myeloma, vertebral metastasis, malignant small round-cell tumor, pancreatic pseudocyst, esophageal duplication cyst, Modic changes in degenerative disc disease, Paget's disease, and psoas hematoma.

Conclusion

Noninfectious spinal conditions can masquerade as spinal tuberculosis, underscoring the importance of obtaining a definitive tissue diagnosis before initiating antitubercular treatment. Particular attention should be given to features such as central lesions and the absence of soft tissue involvement in suspected cases of spinal tuberculosis, warranting a careful reconsideration of the diagnosis.

Postoperative Lumbar Spondylodiscitis Following Transforaminal Endoscopy and Outcomes of Transforaminal Lumbar Interbody Fusion

Objective: To describe the presentation spectrum of postoperative spondylodiscitis (POS<i>e</i>) following transforaminal endoscopic lumbar discectomy and to report the outcomes of transforaminal lumbar interbody fusion (TLIF).Methods: This study analyzed all patients with the classic features of POS<i>e</i> who underwent index surgery elsewhere and presented to us. They had not responded to conservative care for 3 weeks and were operated further with open TLIF. The treatment response was judged by the declining values of inflammatory markers, improvements in mobility, and decreases in pain. Patients’ outcomes were analyzed using a visual analogue scale (VAS), the Oswestry Disability Index (ODI), and the occurrence of complications. Radiological outcomes were assessed by fusion and implant stability. The spectrum of the demographic presentation was analyzed. PubMed was searched to find the incidence of POS<i>e</i> and the spectrum of organisms involved.Results: Fifteen patients were operated primarily by interventionalists and four by surgeons among 19 POS<i>e</i> patients who finally underwent TLIF at Stavya Spine Hospital & Research Institute. Organism culture positivity was found in 10 and no culture results were present in 9 cases. All TLIF cases had a follow-up of 52.94 ± 13.66 months (range, 28–71 months). The preoperative back pain VAS improved from 9.47 ± 0.61 (8–10) to 0.42 ± 0.50 (0–1). The leg pain VAS improved from 5.78 ± 4.19 (6–10) to 0.52 ± 0.61 (0–1). The preoperative ODI improved from 87.01 ± 7.70 (73.33–97.79) to 7.36 ± 8.14 (0–26.67). No major complications occurred. Cure of infection and stable reconstruction with fusion were achieved in all patients.Conclusion: POS<i>e</i> has a very low reported incidence. Standardization of training and sterilization would further reduce its incidence. However, aggressive early TLIF in patients with nonresponding POS<i>e</i> produces beneficial results.

Site matters: Image-guided percutaneous sampling of intervertebral disc results in increased positive diagnostic yield in spondylodiscitis

Spondylodiscitis is a common referral to spinal on call services. Identification of the causative organism is vital in order to dictate the appropriate antibiotic treatment. In this context, the surgical and interventional radiology team is often asked to perform a diagnostic biopsy. The aim of the present study was to assess whether the sampling location affects the diagnostic yield. Our results suggest that the overall positive diagnostic yield was 35%. When disc material was included in the sample the diagnostic yield significantly improved to 47%. Bone sampling alone had a positive yield of 15%. Age, pre-biopsy CRP, pre-biopsy use of antibiotics did not seem to affect the likelihood of obtaining a positive yield. These results suggests that when performing image guided biopsies for suspected cases of spondylodiscitis the inclusion of disc material is important.

Imaging of Spondylodiscitis: An Update

Spondylodiscitis is an infection of the vertebral body and/or intervertebral disc, which can also involve the epidural space, posterior elements, and paraspinal soft tissues. Due to high morbidity and mortality, prompt diagnosis and treatment of spondylodiscitis is critical. However, diagnosis can be challenging due to nonspecific signs and symptoms. Magnetic resonance imaging with and without contrast is the imaging modality of choice due to high sensitivity and specificity. Intravenous administration of gadolinium contrast can better demonstrate the extent of soft tissue and bone abscesses. However, magnetic resonance imaging is less useful in the evaluation of treatment response. When magnetic resonance imaging cannot be performed or is not diagnostic, radionuclide imaging is a useful alternative. Although bone scintigraphy frequently is used as a screening test, false negative results can occur early in the course of the infection and in the elderly. This test is not useful for detecting the soft tissue infections that often accompany or mimic spondylodiscitis. Gallium-67 citrate improves the specificity of the bone scan, can detect infection earlier than the bone scan, may be more sensitive, especially in elderly patients, and identifies accompanying soft tissue infection. Performing SPECT and SPECT/CT improve accuracy. The 2-3 day delay between radiopharmaceutical administration, poor image quality, and relatively high patient radiation dose are significant disadvantages of gallium-67. Furthermore gallium-67 is no longer as readily available as it once was. ¹⁸F-FDG imaging is the radionuclide test of choice for spondylodiscitis. The procedure, completed in one day, is sensitive, has a high negative predictive value, and reliably differentiates degenerative from infectious vertebral body end-plate abnormalities. ¹⁸F-FDG has outperformed bone and gallium-67 imaging in comparative studies. ¹⁸F-FDG may be able to provide an objective means for monitoring response to treatment. The potential of other agents for diagnosing spondylodiscitis has been studied. Although indium-111biotin accurately diagnoses spondylodiscitis, this radiopharmaceutical has never been commercially available. Gallium-68 citrate and ^99mTc-radiolabeled antimicrobial peptides have been investigated, but their role in the diagnosis of spondylodiscitis has not been established. Labeled leukocyte scintigraphy has no role in the diagnosis of spondylodiscitis.

A novel scoring system concept for de novo spinal infection treatment, the Spinal Infection Treatment Evaluation Score (SITE Score): a proof-of-concept study

OBJECTIVE

De novo infections of the spine are an increasing healthcare problem. The decision for nonsurgical or surgical treatment is often made case by case on the basis of physician experience, specialty, or practice affiliation rather than evidence-based medicine. To create a more systematic foundation for surgical assessments of de novo spinal infections, the authors applied a formal validation process toward developing a spinal infection scoring system using principles gained from other spine severity scoring systems like the Spine Instability Neoplastic Score, Thoracolumbar Injury Classification and Severity Score, and AO Spine classification of thoracolumbar injuries. They utilized an expert panel and literature reviews to develop a severity scale called the "Spinal Infection Treatment Evaluation Score" (SITE Score).

METHODS

The authors conducted an evidence-based process of combining literature reviews, extracting key elements from previous scoring systems, and obtaining iterative expert panel input while following a formal Delphi process. The resulting basic SITE scoring system was tested on selected de novo spinal infection cases and serially refined by an international multidisciplinary expert panel. Intra- and interobserver reliabilities were calculated using the intraclass correlation coefficient (ICC) and Fleiss' and Cohen's kappa, respectively. A receiver operating characteristic analysis was performed for cutoff value analysis. The predictive validity was assessed through cross-tabulation analysis.

RESULTS

The conceptual SITE scoring system combines the key variables of neurological symptoms, infection location, radiological variables for instability and impingement of neural elements, pain, and patient comorbidities. Ten patients formed the first cohort of de novo spinal infections, which was used to validate the conceptual scoring system. A second cohort of 30 patients with de novo spinal infections, including the 10 patients from the first cohort, was utilized to validate the SITE Score. Mean scores of 6.73 ± 1.5 and 6.90 ± 3.61 were found in the first and second cohorts, respectively. The ICCs for the total score were 0.989 (95% CI 0.975-0.997, p < 0.01) in the first round of scoring system validation, 0.992 (95% CI 0.981-0.998, p < 0.01) in the second round, and 0.961 (95% CI 0.929-0.980, p < 0.01) in the third round. The mean intraobserver reliability was 0.851 ± 0.089 in the third validation round. The SITE Score yielded a sensitivity of 97.77% ± 3.87% and a specificity of 95.53% ± 3.87% in the last validation round for the panel treatment decision.

CONCLUSIONS

The SITE scoring concept showed statistically meaningful reliability parameters. Hopefully, this effort will provide a foundation for a future evidence-based decision aid for treating de novo spinal infections. The SITE Score showed promising inter- and intraobserver reliability. It could serve as a helpful tool to guide physicians' therapeutic decisions in managing de novo spinal infections and help in comparison studies to better understand disease severity and outcomes.

Differentiating Magnetic Resonance Images of Pyogenic Spondylitis and Spinal Modic Change Using a Convolutional Neural Network

STUDY DESIGN

A retrospective analysis of magnetic resonance imaging (MRI).

OBJECTIVE

The study aimed to evaluate the performance of a convolutional neural network (CNN) to differentiate spinal pyogenic spondylitis from Modic change on MRI. We compared the performance of CNN to that of four clinicians.

SUMMARY OF BACKGROUND DATA

Discrimination between pyogenic spondylitis and spinal Modic change is crucial in clinical practice. CNN deep-learning approaches for medical imaging are being increasingly utilized.

METHODS

We retrospectively reviewed MRIs from pyogenic spondylitis and spinal Modic change patients. There were 50 patients per group. Sagittal T1-weighted (T1WI), sagittal T2-weighted (T2WI), and short TI inversion recovery (STIR) MRIs were used for CNN training and validation. The deep learning framework Tensorflow was used to construct the CNN architecture. To evaluate CNN performance, we plotted the receiver operating characteristic curve and calculated the area under the curve. We compared the accuracy, sensitivity, and specificity of CNN diagnosis to that of a radiologist, spine surgeon, and two orthopedic surgeons.

RESULTS

The CNN-based area under the curves of the receiver operating characteristic curve from the T1WI, T2WI, and STIR were 0.95, 0.94, and 0.95, respectively. The accuracy of the CNN was significantly greater than that of the four clinicians on T1WI and STIR (P<0.05), and better than a radiologist and one orthopedic surgeon on the T2WI (P<0.05). The sensitivity was significantly better than that of the four clincians on T1WI and STIR (P<0.05), and better than a radiologist and one orthopedic surgeon on the T2WI (P<0.05). The specificity was significantly better than one orthopedic surgeon on T1WI and T2WI (P<0.05) and better than both orthopedic surgeons on STIR (P<0.05).

CONCLUSION

We differentiated between Modic changes and pyogenic spondylitis using a CNN that interprets MRI. The performance of the CNN was comparable to, or better than, that of the four clinicians.

Imaging in the Diagnosis of Nonspecific Pyogenic Spondylodiskitis

The prevalence of nonspecific pyogenic spondylodiskitis, associated with both a high morbidity and a high mortality, has increased in the last few decades. The diagnosis is often delayed because of the nonspecific clinical manifestation at the early stage. The reliability of radiographs is limited, particularly in early stage after the onset of infection. Computed tomography (CT) can reliably assess the bony condition with the possibility of spatial visualization. Contrast enhancement supports the detection of affected soft tissue. Magnetic resonance imaging (MRI) continues to be the gold standard in the diagnosis of spondylodiskitis. Sophisticated investigation protocols supported by gadolinium enhancement secure the diagnosis. MRI has a high resolution without radiation exposure. Different nuclear investigation techniques extend the diagnostic options. Reports of 18F-fluorodeoxyglucose-positron emission tomography (18-FDG-PET) are particularly promising to confirm the diagnosis. The drawback of the reduced image quality with respect to detailed anatomical information can be overcome by a combined simultaneous acquisition of CT or MRI. With respect to one of the greatest challenges, the differentiation between degenerative changes (Modic type 1) and infection at an early stage using differentiated MRI protocols and FDG-PET is promising. This overview presents a concise state-of-the-art look at radiologic investigations in case of suspected nonspecific pyogenic spondylodiskitis with the focus on a pragmatic approach.

Paraspinal soft tissue edema ratio: An accurate marker for early lumbar spine spondylodiscitis on an unenhanced MRI

PURPOSE

MRI is currently the gold standard imaging modality in the diagnosis of lumbar spine discitis/osteomyelitis. However, even with supportive clinical and laboratory data, the accuracy of MRI remains limited by several degenerative and inflammatory mimics, such that it continues to represent a challenge for radiologists. This study reports a new quantitative imaging marker of lumbar paraspinal soft tissue edema which shows significant accuracy for spondylodiscitis.

METHODS

Thirty-five patients with equivocal MRI findings of lumbar discitis/osteomyelitis vs endplate degenerative changes were reviewed over a 24-month period. Patients with a history of surgery, fractures/recent trauma, signs of advanced infection such as abscesses, phlegmon or severe osseous destruction were excluded. Two ABR board certified neuroradiologists who were blinded to the final diagnosis evaluated a new marker; the superior-inferior paraspinal edema ratio (SI-PER). The SI-PER was obtained by measuring the superior-inferior extent of increased signal/edema in the paraspinal soft tissues on the paraspinal inversion recovery images divided by the vertebral body height measured at midpoint. Cases positive for spondylodiscitis were those confirmed by biopsy, aspiration/drainage, surgery, or clinical improvement following antibiotic treatment. The diagnostic sensitivity and specificity of SI-PER were determined by Receiver operating characteristic (ROC) analysis.

RESULTS

In 23/35 (66%) patients, the diagnosis of discitis/osteomyelitis was confirmed. The SI-PER showed a significant association with a positive MRI diagnosis (p = 0.001). Inter-observer correlation for SI-PER was 0.92. ROC analysis showed an area under the curve of 0.84. A SI-PER of 2.5 was 96% sensitive and 75% specific for the diagnosis of discitis/osteomyelitis, with a PPV of 88% and a NPV of 90%.

CONCLUSION

In this study, the superior inferior paraspinal edema ratio (SI-PER), a newly defined MRI marker, was found to have high sensitivity for differentiating spondylodiscitis from endplate degenerative changes on lumbar spine MRI.

A Review of Posteromedial Lesions of the Chest Wall: What Should a Chest Radiologist Know?

A heterogeneous group of tumors can affect the posteromedial chest wall. They form diverse groups of benign and malignant (primary or secondary) pathologies that can arise from different chest wall structures, i.e., fat, muscular, vascular, osseous, or neurogenic tissues. Chest radiography is very nonspecific for the characterization of chest wall lesions. The modality of choice for the initial assessment of the chest wall lesions is computed tomography (CT). More advanced cross-sectional modalities such as magnetic resonance imaging (MRI) and positron emission tomography (PET) with fluorodeoxyglucose are usually used for further characterization, staging, treatment response, and assessment of recurrence. A systematic approach based on age, clinical history, and radiologic findings is required for correct diagnosis. It is essential for radiologists to be familiar with the spectrum of lesions that might affect the posteromedial chest wall and their characteristic imaging features. Although the imaging findings of these tumors can be nonspecific, cross-sectional imaging helps to limit the differential diagnosis and determine the further diagnostic investigation (e.g., image-guided biopsy). Specific imaging findings, e.g., location, mineralization, enhancement pattern, and local invasion, occasionally allow a particular diagnosis. This article reviews the posteromedial chest wall anatomy and different pathologies. We provide a combination of location and imaging features of each pathology. We will also explore the role of imaging and its strengths and limitations for diagnosing posteromedial chest wall lesions.

MRI Features Associated With the Detection of Microbial Pathogens by CT-Guided Biopsy in Septic Spondylodiscitis

OBJECTIVE

The aim of this study was to assess the magnetic resonance imaging (MRI) features associated with microbial pathogen detection by computed tomography (CT)-guided biopsy in patients with suspected septic spondylodiscitis.

METHODS

For the last 10-year period, we analyzed the medical records of patients who underwent MRI and CT-guided biopsy for suspected septic spondylodiscitis. Clinical characteristics were recorded. The following MRI features were assessed: edema or contrast enhancement of the intervertebral disc, adjacent vertebrae, epidural and paravertebral space, presence of abscess, and paravertebral edema size. A positive biopsy was defined by pathogen identification on bacterial analysis or the presence of granuloma on histology. Predictors of a positive biopsy were assessed with a logistic regression model.

RESULTS

We examined data for 61 patients (34 [56%] male; mean age, 59.9 ± 18.0 years); for 35 patients (57%), CT-guided biopsy was positive for a pathogen. The 4 MRI findings significantly associated with a positive biopsy were epiduritis, greater than 50% vertebral endplate edema, loss of intradiscal cleft, and abscess. The size of paravertebral edema was greater with a positive than negative biopsy (median, 15.9 [interquartile range, 11.3-21.3] vs 7.3 [4.6-12.9] mm; p = 0.004). On multivariable analysis, epiduritis was the only independent predictor of a positive biopsy (adjusted odds ratio, 7.4 [95% confidence interval, 1.7-31.4]; p = 0.006).

CONCLUSIONS

Epiduritis and the size of paravertebral edema on MRI are associated with detection of a microbial pathogen in suspected septic spondylodiscitis. For patients without these MRI signs, the need for further investigations such as enriched or prolonged cultures, a second CT-guided biopsy, or even surgical biopsy need to be discussed.

Proton Density Fat Fraction Spine MRI for Differentiation of Erosive Vertebral Endplate Degeneration and Infectious Spondylitis

Vertebral Modic type 1 (MT1) degeneration may mimic infectious disease on conventional spine magnetic resonance imaging (MRI), potentially leading to additional costly and invasive investigations. This study evaluated the diagnostic performance of the proton density fat fraction (PDFF) for distinguishing MT1 degenerative endplate changes from infectious spondylitis. A total of 31 and 22 patients with equivocal diagnosis of MT1 degeneration and infectious spondylitis, respectively, were retrospectively enrolled in this IRB-approved retrospective study and examined with a chemical-shift encoding (CSE)-based water-fat 3D six-echo modified Dixon sequence in addition to routine clinical spine MRI. Diagnostic reference standard was established according to histopathology or clinical and imaging follow-up. Intravertebral PDFF [%] and PDFFratio (i.e., vertebral endplate PDFF/normal vertebrae PDFF) were calculated voxel-wise within the single most prominent edematous bone marrow lesion per patient and examined for differences between MT1 degeneration and infectious spondylitis. Mean PDFF and PDFFratio of infectious spondylitis were significantly lower compared to MT1 degenerative changes (mean PDFF, 4.28 ± 3.12% vs. 35.29 ± 17.15% [p < 0.001]; PDFFratio, 0.09 ± 0.06 vs. 0.67 ± 0.37 [p < 0.001]). The areas under the curve (AUC) and diagnostic accuracies were 0.977 (p < 0.001) and 98.1% (cut-off at 12.9%) for PDFF and 0.971 (p < 0.001) and 98.1% (cut-off at 0.27) for PDFFratio. Our data suggest that quantitative evaluation of vertebral PDFF can provide a high diagnostic accuracy for differentiating erosive MT1 endplate changes from infectious spondylitis.

Clinicoradiographic predictors of percutaneous bone biopsy results among patients with suspected thoracolumbar spine infection

BACKGROUND

Image-guided percutaneous thoracolumbar spine biopsy is frequently performed in the setting of suspected septic facet arthritis or discitis osteomyelitis (DOM). There are limited data regarding factors associated with a positive biopsy result among these patients.

MATERIALS AND METHODS

Patients with suspected DOM who underwent spine biopsy were identified. Samples yielding a positive culture and/or histopathology suggestive of acute osteomyelitis were considered positive. The associations between selected medical comorbidities, laboratory values, pre-biopsy antibiotic administration, imaging findings and biopsy results were investigated.

RESULTS

121 patients underwent percutaneous biopsy with 35.5% yielding positive results. Biopsy results showed no correlation with comorbidities. The only laboratory value that correlated with a positive biopsy yield was blood culture positivity (p = 0.03). The imaging findings that correlated with a positive biopsy yield were the presence of a paraspinal fluid collection or epidural abscess (p = 0.003 and 0.018, respectively). Sampling paraspinal fluid collections, when present, resulted in a higher rate of a positive biopsy yield compared to sampling of bone or disc (p = 0.006). Patients who received antibiotics had a higher rate of a positive biopsy yield (p = 0.014). In those with positive blood cultures, biopsy yielded the same antimicrobial susceptibility profile in 13/14 cases.

CONCLUSION

The presence of a paraspinal fluid collection or epidural abscess is correlated with positive biopsy yield, and paraspinal fluid collections should be targeted for biopsy. Other imaging findings did not correlate with biopsy yield. Biopsy may not offer additional information for patients with positive blood cultures.

Management of Pyogenic Spondylodiscitis Following Nonspinal Surgeries: A Tertiary Care Center Experience

BACKGROUND

The literature is lacking on the incidence and management of pyogenic spondylodiscitis (PS) following routine elective surgical procedures. This study aimed to analyze the presentation and treatment outcome in patients with PS following nonspinal surgeries at a tertiary care center with a minimum follow-up of 12 months.

METHODS

The demographic, clinical-radiologic features, and treatment outcomes in 40 patients with a diagnosis of PS following nonspinal surgical procedures were retrospectively reviewed and analyzed.

RESULTS

The mean age at presentation was 36.4 ± 11.8 years, with 80% of patients being female. The common surgical procedures associated with PS were cesarean delivery (30%), gastric sleeve surgery (12.5%), and dilatation and curettage (12.5%). The tissue biopsy culture was positive in 82.5% of patients. A total of 26 patients (65%) were treated with conservative management and 14 patients (35%) were treated surgically. The mean pretreatment Core Outcome Measure Index score significantly decreased at 12 months (P < .0001) after treatment. The mean pretreatment erythrocyte sedimentation rate (P < .0001) and C-reactive protein (P < .0001) levels significantly decreased at 12 months after treatment.

CONCLUSIONS

With most patients with PS following nonspinal surgeries treated with conservative management, excellent clinical outcomes were achieved in all patients at 12 months after treatment. The diagnosis of PS should be considered in patients presenting with low back pain (LBP) with a recent history of undergoing a nonspinal surgical procedure. Patients who undergo surgical procedures are an important "at-risk" patient population, and early diagnosis and treatment can help achieve excellent clinical outcomes. Further studies are required to determine risk factors and possible perioperative precautions that can be taken to prevent PS in patients who undergo nonspine surgeries.

LEVEL OF EVIDENCE

3.

CLINICAL RELEVANCE

Pyogenic spondylodiscitis should be suspected in patients presenting with LBP after a recent non-spinal surgical procedure. Early diagnosis and treatment can help achieve excellent clinical outcomes in these patients.

Metastatic Adenocarcinoma of the Lung Mimicking Miliary Tuberculosis and Pott's Disease

Tuberculous spondylitis (Pott’s disease) is among the frequent extra-pulmonary presentations of tuberculosis (TB). The global incidence of lung adenocarcinoma is on the rise, and it is a rare differential diagnosis of miliary shadows on chest imaging. It has a predilection to metastasize to ribs and spine in particular. There is a very close clinical and radiological resemblance in the presentation of spinal metastasis of lung cancer and Potts’s disease. It poses a diagnostic challenge to clinicians particularly in TB endemic areas to arrive at an accurate diagnosis, leading to disease progression and poor outcome. We report a 54-year-old female patient presented with constitutional symptoms of on and off fever and back pain. Her chest X-ray revealed miliary shadows, and acid-fast bacilli (AFB) sputum smear and TB polymerase chain reaction (PCR) test came negative; radiological diagnosis of tuberculous spondylitis was done on computerized tomography (CT) chest and magnetic resonance imaging (MRI) spine. Subsequent bronchoscopy and bronchoalveolar lavage (BAL) cytology showed malignant cells and CT-guided lung biopsy confirmed lung adenocarcinoma with spinal and brain metastasis. Despite being started on chemo-immunotherapy and radiotherapy her outcome was poor due to advanced metastatic disease. This case highlights the significance of considering metastatic adenocarcinoma of the lung a rare but ominous possibility in the differential diagnosis of miliary shadows on chest imaging. Early bronchoscopy and biopsy must be considered in all patients presenting with miliary pulmonary lesions and spinal lesions to make a correct diagnosis, preventing an unnecessary delay in starting proper treatment and poor outcome. It also emphasizes the importance of better understanding the different radiographic features of the two common mimics, spinal tuberculosis, and metastatic spinal tumors.

Pathophysiology and MRI Findings of Infectious Spondylitis and the Differential Diagnosis

MRI에서 추간판의 이상 신호와 위, 아래 척추체 종판의 파괴, 종판 주변의 골수부종 등은 감염성 척추염의 전형적인 소견으로 여겨지나 퇴행성 척추질환, acute Schmorl's node, 척추관절병증, synovitis, acne, pustulosis, hyperostosis, and osteitis (SAPHO)/chronic recurrent multifocal osteomyelitis, 척추신경관절병증, calcium pyrophosphate dehydrate 결절침착질환 등 다양한 비감염성 척추질환에서도 나타날 수 있다. MRI에서 이러한 비감염성 척추질환과 감별되는 감염성 척추염의 영상 소견은 추간판의 고신호와 농양, 척추 연부조직의 농양, 그리고 T1 강조영상에서 저신호로 보이는 종판의 경계가 불명확해지는 점 등이다. 그러나 이러한 감별점이 항상 적용되는 것은 아니며 감염성, 비감염성 질환의 영상 소견에 유사점이 많기 때문에 정확한 진단을 위해서는 감염성 척추염뿐만 아니라 감염과 감별해야 하는 다양한 질환의 병태생리와 연관된 영상학적 특징을 아는 것이 중요하다.

Nontraumatic Spinal Cord Compression: MRI Primer for Emergency Department Radiologists

The occurrence of acute myelopathy in a nontrauma setting constitutes a medical emergency for which spinal MRI is frequently ordered as the first step in the patient's workup. The emergency department radiologist should be familiar with the common differential diagnoses of acute myelopathy and be able to differentiate compressive from noncompressive causes. The degree of spinal cord compression and presence of an intramedullary T2-hyperintense signal suggestive of an acute cord edema are critical findings for subsequent urgent care such as surgical decompression. Importantly, a delay in diagnosis may lead to permanent disability. In the spinal canal, compressive myelopathy can be localized to the epidural, intradural extramedullary, or intramedullary anatomic spaces. Effacement of the epidural fat and the lesion's relation to the thecal sac help to distinguish an epidural lesion from an intradural lesion. Noncompressive myelopathy manifests as an intramedullary T2-hyperintense signal without an underlying mass and has a wide range of vascular, metabolic, inflammatory, infectious, and demyelinating causes with seemingly overlapping imaging appearances. The differential diagnosis can be refined by considering the location of the abnormal signal intensity within the cord, the longitudinal extent of the disease, and the clinical history and laboratory findings. Use of a compartmental spinal MRI approach in patients with suspected nontraumatic spinal cord injury helps to localize the abnormality to an epidural, intradural extramedullary, or intramedullary space, and when combined with clinical and laboratory findings, aids in refining the diagnosis and determining the appropriate surgical or nonsurgical management.Online supplemental material is available for this article.^©RSNA, 2019.

Lumbosacral discitis as a rare complication of laparoscopic sacrocolpopexy

INTRODUCTION AND HYPOTHESIS

Sacrocolpopexy is considered to be the gold-standard procedure for apical compartment prolapse. However, complications such as sacral hemorrhage, small bowel obstruction, port site herniation, mesh erosion, mesh exposure, and occasionally discitis may occur. The aim of this study is to show laparoscopic treatment of L5-S1 discitis 3 months following laparoscopic sacrocolpopexy.

METHODS

Two surgical interventions of a case with narrated video footage is presented.

RESULTS

Laparoscopic sacrocolpopexy following hysterectomy in the first part and re-laparoscopy because of a diagnosis of discitis refractory to medical treatment, and removal of mesh along with anterior L5-S1 discectomy for curative debridement in the second part is demonstrated.

CONCLUSION

Frequency of postoperative discitis has been increased by the widespread use of a laparoscopic approach. In order to reduce the complication rate, surgical technique allowing the needle to penetrate only the depth of the anterior longitudinal ligament and usage of monofilament suture for mesh attachment is recommended. In treatment, removal of the sacral mesh, and even extensive tissue debridement, may be necessary.

An Institutional Review of Tuberculosis Spine Mimics on MR Imaging: Cases of Mistaken Identity

Although MRI has a spectrum of findings which help in the diagnosis of tuberculosis (TB) spine, a broad spectrum of spine pathologies resemble Pott's spine on MRI and are often missed due to inadequate clinical details. As a result, patients are often subject to unnecessary biopsy. A blinded radiologist may misdiagnose such mimic cases as TB. Our aim is to enable the reader to learn the main criteria that differentiate spine TB from other spine etiologies that mimic TB. A retrospective search was done and authors collected only MRI spine reports that showed a differential diagnosis or diagnosis of TB spine from the computer-based data records of the institution over a four-year period. This revealed 306 cases of TB spine out of which 78 cases with an alternate diagnosis that resembled TB spine were included. We describe a single institute review of 78 such cases that resemble and mimic Pott's spine on MRI. The cases being: (n = 15) pyogenic spondylitis, (n = 1) brucellar spondylodiscitis, (n = 12) rheumatoid arthritis, (n = 12) metastases, (n = 8) lymphoma, (n = 5) post-trauma fractures, (n = 10) degenerative disc disease, (n = 2) Baastrup's disease, (n = 9) osteoporotic fracture, (n = 3) spinal neuropathic arthritis, and (n = 1) case of Rosai-Dorfman disease. The clinical and radiological findings of all these cases were correlated with lab findings and histopathology wherever necessary. Appropriate recognition of these entities that resemble and mimic TB spine on MRI is important for optimal patient care. This paper exposes radiologists to a variety of spine pathologies for which biopsy is not indicated, and highlights key imaging findings of these entities to facilitate greater diagnostic accuracy in clinical practice.

CORRELATION BETWEEN FINDINGS IN MAGNETIC RESONANCE AND BIOPSY IN THE DIAGNOSIS OF SPONDYLODISCITIS

ABSTRACT Objective To correlate magnetic resonance imaging (MRI) findings with the microbiological and anatomopathological diagnosis of spinal infection. Methods A retrospective, cohort review of online medical records (laboratory, anatomopathology and diagnostic imaging sector) of patients diagnosed with spondylodiscitis, who underwent a full spine MR scan between January 2014 and July 2018 at the Department of Orthopedics and Traumatology of the Universidade Federal de São Paulo. Results Staphylococcus aureus was the most commonly found etiological agent (57%). Blood culture was positive in 76% of cases and 82% of the patients who underwent biopsy had a spondylodiscitis diagnosis. Pain was the most prevalent clinical symptom and the lumbosacral spine was the most frequent site of infection. T1 hyposignal, T2/STIR hypersignal, and terminal plate destruction were verified in almost all MR scans. Conclusions No direct correlation was found between MR findings and any specific etiological agent. Blood culture and biopsy are important diagnostic tools that should be used for accurate diagnosis of the infectious agent . Level of evidence IV; Diagnostic Study.

Vertebral Bone Marrow and Endplate Assessment on MR Imaging for the Differentiation of Modic Type 1 Endplate Changes and Infectious Spondylodiscitis

On magnetic resonance (MR) imaging, Modic type 1 (MT1) endplate changes and infectious spondylodiscitis share similar findings. Therefore, this study investigated vertebral bone marrow and endplate changes to enable their differentiation. The lumbar spine MR examinations of 91 adult patients were retrospectively included: 39 with MT1; 19 with early spondylodiscitis without abscess; and 33 with advanced spondylodiscitis with abscess. The assessment included percentage of bone marrow edema on sagittal short tau inversion recovery images, and the signal ratio of edema to unaffected bone and endplate contour (normal; irregular, yet intact; blurred; destructive) on sagittal unenhanced T1-weighted images. Differences were tested for statistical significance by Chi-square test and mixed model analysis of variance. The MR diagnostic accuracy in differentiating MT1 and spondylodiscitis was assessed by cross-tabulation and receiver-operating characteristic analysis. The endplate contours, edema extents, and T1-signal ratios of MT1 (extent, 31.96%; ratio, 0.83) were significantly different (p < 0.001) from early spondylodiscitis (56.42%; 0.60), and advanced spondylodiscitis (91.84%; 0.61). The highest diagnostic accuracy (sensitivity, 94.87%; specificity, 94.23%; accuracy, 94.51%) in identifying MT1 was provided by an irregular, yet intact endplate contour. This may be a useful MR feature for the differentiation between MT1 and spondylodiscitis, particularly in its early stage.

Postoperative Lumbar Pyogenic Spondylodiscitis: An Institutional Review

Background   Postoperative discitis (POD) remains a dreaded complication in the present era of asepsis. The treatment has been traditionally conservative, but the safety of spinal implants in infective settings has prompted the surgeons to provide rigid immobilization for promoting healing. A major concern in a country like ours is huge patient inflow and long waiting list added to the woe of patient's refusal for a second operative intervention after a first undesirable outcome. Objectives  The aim of the study was to evaluate the functional and radiological outcome of conservative management of POD and determine the methods of prevention. Settings and Design   A retrospective case study series in a tertiary-level hospital. Materials and Methods   Between January 2015 and 2017, 12 cases of POD (10 own and 2 referred) were managed and followed up clinically, radiologically, and with laboratory investigation. Two cases were managed surgically-one with kyphotic deformity and the other with discharging pus. Rest were managed conservatively with analgesics and intravenously followed by oral antibiotics. At 1-year follow-up, patient satisfaction was evaluated using the MacNab outcome assessment. Statistical Analysis   The descriptive data were analyzed mainly by descriptive statistics using mean, median, standard deviation, and interquartile range. Results   Mean follow-up in our series was 15.2 months. Except for two operated cases, we did not go for the invasive procedure for isolation of organism in any of our cases. The total duration of antibiotic in our series was for the mean of 7.3 weeks. Visual analog scale score returned from8 initially to baseline and at final follow-up-4 excellent, 6 good, and 2 had fair outcome. There was no adverse outcome. Conclusions   The majority of POD can be managed conservatively. Surgery is reserved only for special cases. Magnetic resonance imaging is the investigation of choice for diagnosing discitis. Intraoperative use of gentamicin-mixed normal saline wash reduces the incidence of discitis.

Infectious Spondylitis Mimics: Mechanisms of Disease and Imaging Findings

Infectious processes of the spine are on the rise; in this scenario recognition of entities imitating infection is very important. The discovertebral unit is regarded as one of the most important and active sites in the spine. Importantly, the vertebral bony rim and the anterior corners of the vertebral bodies have significant vascularization, they are the last regions to ossify in the developmental process and suffer mechanical forces. Early septic or aseptic discitis-osteomyelitis, properly called spondylitis, involves these anterior regions. Early degeneration is characterized by disc desiccation; however, there is preferential involvement for the corners of the vertebral bodies as well. Many entities to include degenerative changes, inflammatory spondyloarthropathies, neuropathic spine, or pseudo arthrosis, among others, affect the discovertebral unit and can imitate infection. With some exceptions, important imaging findings for the identification of an infectious mimic include the absence of soft tissue enhancement or fluid collections in the paraspinal or epidural regions, and the involvement of multiple levels or the posterior elements. We review developmental, anatomical, and pathologic concepts correlating with imaging clues. Overall, our goal is to increase awareness and to improve recognition of mimicking entities.

Performance of the deep convolutional neural network based magnetic resonance image scoring algorithm for differentiating between tuberculous and pyogenic spondylitis

The purpose of this study was to evaluate the performance of the deep convolutional neural network (DCNN) in differentiating between tuberculous and pyogenic spondylitis on magnetic resonance (MR) imaging, compared to the performance of three skilled radiologists. This clinical retrospective study used spine MR images of 80 patients with tuberculous spondylitis and 81 patients with pyogenic spondylitis that was bacteriologically and/or histologically confirmed from January 2007 to December 2016. Supervised training and validation of the DCNN classifier was performed with four-fold cross validation on a patient-level independent split. The object detection and classification model was implemented as a DCNN and was designed to calculate the deep-learning scores of individual patients to reach a conclusion. Three musculoskeletal radiologists blindly interpreted the images. The diagnostic performances of the DCNN classifier and of the three radiologists were expressed as receiver operating characteristic (ROC) curves, and the areas under the ROC curves (AUCs) were compared using a bootstrap resampling procedure. When comparing the AUC value of the DCNN classifier (0.802) with the pooled AUC value of the three readers (0.729), there was no significant difference (P = 0.079). In differentiating between tuberculous and pyogenic spondylitis using MR images, the performance of the DCNN classifier was comparable to that of three skilled radiologists.

Lumbar Vertebral Endplate Defects on Magnetic Resonance Images: Classification, Distribution Patterns, and Associations with Modic Changes and Disc Degeneration

STUDY DESIGN

A cross-sectional magnetic resonance (MR) imaging study.

OBJECTIVE

To classify and characterize endplate defects using routine lumbar MR images and to determine associations of endplate defects with Modic changes (MCs) and disc degeneration.

SUMMARY OF BACKGROUND DATA

Previously, a cadaveric study revealed that endplate lesions were common and associated with back pain history. New in vivo approaches appropriate for clinical studies are needed to further this potentially important line of research on the clinical significance of endplate lesions, including their relation with MCs, disc degeneration, and back pain.

METHODS

Using a MRI archive, 1564 endplates of 133 subjects (59 men and 74 women, mean age 58.9 ± 11.9 years) with the presence of MCs were retrospectively collected from April of 2014 to June of 2015. On the basis of morphological characteristics, a protocol was proposed to identify three distinct types of endplate defects, including focal, corner, and erosive defects. The location, size, and distribution patterns of various endplate lesions were characterized. MCs and disc degeneration were measured to examine their associations with endplate defects.

RESULTS

Endplate defects were observed in 27.8% of endplates studied. Greater age was associated with the presence of endplate defects. Focal defects were the most common (13.5%), followed by erosive defects (11.1%) and corner defects (3.2%). Defect types also differed in size and distribution patterns. Endplate defects and MCs had similar distribution patterns in the lumbar spine. The presence of endplate defects were associated with the presence of MCs (odds ratio = 4.29, P < 0.001), and associated with less disc signal intensity and disc height, and greater disc bulging (P < 0.05).

CONCLUSION

The three endplate defects identified on routine MR images appear to represent different pathologies and may play a key role in the pathogenesis of MCs. This classification system may facilitate clinical studies on endplate defects.

LEVEL OF EVIDENCE

4.

Imaging of Spondylodiscitis

Spondylodiscitis is an infection of the vertebral body or disc and may also involve the epidural space, posterior elements, and paraspinal soft tissues. It is a cause of morbidity and mortality, and warrants early diagnosis and prompt treatment. Diagnosis can be difficult because of nonspecific signs and symptoms. Magnetic resonance imaging is sensitive and specific and is the imaging modality of choice for spondylodiscitis. Gadolinium contrast can show the extent of soft tissue and bone phlegmon and abscess. The test is less useful for evaluating treatment response. When magnetic resonance imaging cannot be performed or is not diagnostic, radionuclide imaging is a useful alternative. Although bone scintigraphy frequently is used as a screening test, false-negative results can occur, especially in the elderly. This test is not useful for detecting soft tissue infections that accompany or mimic spondylodiscitis. Gallium-67 citrate improves the specificity of the bone scan, can detect infection earlier than the bone scan, may be more sensitive, especially in elderly patients, and identifies accompanying soft tissue infection. Performing SPECT and SPECT/CT improves accuracy. The 2- to 3-day delay between radiopharmaceutical administration and the relatively poor image quality are significant disadvantages of gallium-67. Indium-111 biotin, alone or in combination with streptavidin, accurately diagnoses spondylodiscitis; unfortunately, this agent is not widely available. Currently, ¹⁸F-FDG imaging is the radionuclide test of choice for spondylodiscitis. The procedure, which is completed in a single session, is sensitive, has a high negative predictive value, and reliably differentiates degenerative from infectious vertebral body end plate abnormalities. In comparative investigations, ¹⁸F-FDG has outperformed bone and gallium-67 imaging. Preliminary data suggest that ¹⁸F-FDG may be able to provide an objective means to measure response to treatment. Gallium-68 citrate and 99mTc-radiolabeled antimicrobial peptides have been investigated, but their role in spondylodiscitis has yet to be established.