Differentiation of tuberculosis and metastatic cancer in the spine using dynamic contrast-enhanced MRI

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.

Contrast-enhanced magnetic resonance image segmentation based on improved U-Net and Inception-ResNet in the diagnosis of spinal metastases

Objective

The objective of this study was to investigate the use of contrast-enhanced magnetic resonance imaging (CE-MRI) combined with radiomics and deep learning technology for the identification of spinal metastases and primary malignant spinal bone tumor.

Methods

The region growing algorithm was utilized to segment the lesions, and two parameters were defined based on the region of interest (ROI). Deep learning algorithms were employed: improved U-Net, which utilized CE-MRI parameter maps as input, and used 10 layers of CE images as input. Inception-ResNet model was used to extract relevant features for disease identification and construct a diagnosis classifier.

Results

The diagnostic accuracy of radiomics was 0.74, while the average diagnostic accuracy of improved U-Net was 0.98, respectively. the PA of our model is as high as 98.001%. The findings indicate that CE-MRI based radiomics and deep learning have the potential to assist in the differential diagnosis of spinal metastases and primary malignant spinal bone tumor.

Conclusion

CE-MRI combined with radiomics and deep learning technology can potentially assist in the differential diagnosis of spinal metastases and primary malignant spinal bone tumor, providing a promising approach for clinical diagnosis.

Identification of Origin for Spinal Metastases from MR Images: Comparison Between Radiomics and Deep Learning Methods

OBJECTIVE

To determine whether spinal metastatic lesions originated from lung cancer or from other cancers based on spinal contrast-enhanced T1 (CET1) magnetic resonance (MR) images analyzed using radiomics (RAD) and deep learning (DL) methods.

METHODS

We recruited and retrospectively reviewed 173 patients diagnosed with spinal metastases at two different centers between July 2018 and June 2021. Of these, 68 involved lung cancer and 105 were other types of cancer. They were assigned to an internal cohort of 149 patients, randomly divided into a training set and a validation set, and to an external cohort of 24 patients. All patients underwent CET1-MR imaging before surgery or biopsy. We developed two predictive algorithms: a DL model and a RAD model. We compared performance between models, and against human radiological assessment, via accuracy (ACC) and receiver operating characteristic (ROC) analyses. Furthermore, we analyzed the correlation between RAD and DL features.

RESULTS

The DL model outperformed RAD model across the board, with ACC/ area under the receiver operating characteristic curve (AUC) values of 0.93/0.94 (DL) versus 0.84/0.93 (RAD) when applied to the training set from the internal cohort, 0.74/0.76 versus 0.72/0.75 when applied to the validation set, and 0.72/0.76 versus 0.69/0.72 when applied to the external test cohort. For the validation set, it also outperformed expert radiological assessment (ACC: 0.65, AUC: 0.68). We only found weak correlations between DL and RAD features.

CONCLUSION

The DL algorithm successfully identified the origin of spinal metastases from pre-operative CET1-MR images, outperforming both RAD models and expert assessment by trained radiologists.

Diagnosis and Treatment of Skipped Multifocal Spinal Tuberculosis Lesions

Spinal tuberculosis, also known as Pott's disease or tuberculous spondylitis, is usually secondary to primary infection in the lungs or other systems, and in most instances, is thought to be transmitted via blood. Typical manifestations of infection include narrowing of the intervertebral disc by erosion and bone destruction of adjacent vertebrae. Atypical spinal tuberculosis is a specific type of spinal tuberculosis. It mainly consists of single vertebral lesions, single posterior structure lesions, multiple vertebral lesions, and intra-spinal lesions. Skipped multifocal spinal tuberculosis is one of these types and is characterized by two or more vertebral lesions without the involvement of the adjoining intervertebral discs, regardless of their location. To date, only a few cases have been reported. Upon clinical admission, it can be treated conservatively or surgically, depending on the patient's symptoms. In addition, gene or biological therapies are being investigated. However, because of the exceptional imaging findings and insidious symptoms, it is often misdiagnosed as a neoplastic lesion, osteoporotic fracture, or other infectious spondylitis, increasing the risk of neurological deficit and kyphotic deformity, and delaying the optimal treatment window. In this study, we review the diagnosis and treatment strategies for skipped multifocal spinal tuberculosis lesions and enumerate the common differential diagnoses, to provide reference and guidance for clinical treatment and diagnosis direction.

Advances in Bone Marrow Imaging: Strengths and Limitations from a Clinical Perspective

Conventional magnetic resonance imaging (MRI) remains the modality of choice to image bone marrow. However, the last few decades have witnessed the emergence and development of novel MRI techniques, such as chemical shift imaging, diffusion-weighted imaging, dynamic contrast-enhanced MRI, and whole-body MRI, as well as spectral computed tomography and nuclear medicine techniques. We summarize the technical bases behind these methods, in relation to the common physiologic and pathologic processes involving the bone marrow. We present the strengths and limitations of these imaging methods and consider their added value compared with conventional imaging in assessing non-neoplastic disorders like septic, rheumatologic, traumatic, and metabolic conditions. The potential usefulness of these methods to differentiate between benign and malignant bone marrow lesions is discussed. Finally, we consider the limitations hampering a more widespread use of these techniques in clinical practice.

Early diagnosis of spinal tuberculosis by magnetic resonance: perfusion weighted imaging in a rabbit model

BACKGROUND

This study aimed to analyze the application value of magnetic resonance (MR)-perfusion weighted imaging (PWI) in the early imaging diagnosis of rabbit spinal tuberculosis.

METHODS

Spinal tuberculosis model was established using ATCC25177 Mycobacterium tuberculosis strain in the lumbar spine of rabbits. Forty rabbits were divided into 2 groups: rabbits in the experiment group were injected with 0.2 ml of 5.0 mg/ml tuberculosis suspension (n = 30) and those in the control group were injected with 0.2 ml of normal saline (n = 10) after vertebrae drilling surgery. Routine MRI and MR-PWI were performed at 4, 6, and 8 weeks after surgery. The statistical difference in terms of perfusion parameter values in the early MR-PWI scan of spinal tuberculosis between two groups was analyzed. The receiver operating characteristic (ROC) curve analysis was conducted for the accuracy of MR-PWI parameters in the early diagnosis of spinal tuberculosis.

RESULTS

Except time to peak, the other perfusion parameters in the experiment group were all increased with time. In addition, the difference between the two groups, as well as the differences at each time point was statistically significant (all P < 0.05). First-pass enhancement rate (Efirst), early enhancement rate (Ee), peak height (PH), maximum slope of increase (MSI), maximum signal enhancement rate (Emax) and signal enhancement rate (SER) showed high values in early diagnosing spinal tuberculosis.

CONCLUSION

The parameters including Efirst, Ee, PH, MSI, Emax and SER may provide valuable imaging evidence for the early diagnosis of spinal tuberculosis in clinical application.

Imaging update in spinal tuberculosis

Tuberculosis is ancient disease known to mankind. Diagnosis and management of spinal tuberculosis has immensely improved in last few decades. Imaging, particularly MRI, plays important role in diagnosis of spinal tuberculosis and its complications. Four common imaging patterns of spinal tuberculosis include paradiscal type, central type, Anterior subligamentous type, and posterior type. Imaging also plays important role in differentiation of spinal tuberculosis from its mimics, particularly pyogenic spondylitis, and metastasis. Radiological interventions, such as CT guided vertebral biopsy, and percutaneous drainage of cold abscess, are commonly used in management of spinal tuberculosis. Monitoring of therapeutic response is often based on clinical evaluation and imaging. MRI is most common imaging modality used. Signs of healing include bony ankylosis, resolution of marrow edema, decrease in contrast enhancement, and fatty change with in bone marrow. PET CT is recently evaluated for response assessment with promising results. This review summarizes pathophysiology, clinical presentation, imaging features, radiological interventions, and response assessment in spinal tuberculosis.

Dynamic contrast-enhanced magnetic resonance perfusion volumetrics can differentiate tuberculosis of the spine and vertebral malignancy

BACKGROUND

There is considerable overlap in radiologic features of tubercular and malignant spinal lesions on conventional magnetic resonance imaging (MRI).

PURPOSE

To evaluate the role of dynamic contrast-enhanced (DCE) MRI perfusion parameters in differentiating vertebral malignancy from spinal tuberculosis.

MATERIAL AND METHODS

This was a prospective study and we enrolled consecutive patients presenting with a clinical/radiologic evidence of vertebral lesions. DCE-MRI of the spine was performed using 3D volume interpolated breath-hold examination (VIBE) sequence after intravenously injecting 0.1 mmol/kg body weight of gadopentetate dimeglumine. We used Tofts model to calculate DCE parameters that included K^trans (transfer constant), k_ep (rate constant), v_e (fractional volume of extracellular extravascular space), and iAUC (initial area under the curve). We compared the mean value of each perfusion parameter by type of lesion (tubercular/malignant) at 0.05 significance level and performed receiver operating characteristic curve analysis.

RESULTS

We could confirm histologic/cytologic diagnosis in 35 of the 45 patients recruited. Of these, 19 were tubercular and 16 were malignant lesions. The mean (± standard deviation) of k_ep (min^-1) was significantly higher (2.89 ± 3.3) in malignant compared to tubercular lesions (0.81 ± 0.19), whereas v_e was significantly lower in malignant (0.27 ± 0.13 mL/g) compared to benign lesions (0.47 ± 0.12 mL/g) at 0.05 significance level. k_ep cutoff of ≥1.17 min^-1 had a sensitivity of 93.8% and specificity of 100% with a diagnostic accuracy of 94.4% in detecting malignant disease.

CONCLUSION

High k_ep is the single best predictor of malignant vertebral lesions. We recommend k_ep cutoff value of ≥1.17 min^-1 that has high diagnostic accuracy in identifying malignant lesions.

Cervical spine TB - Current concepts in management

OBJECTIVE

Cervical tubercular disease (CTB) is a rare pathology and constitutes 3-5% of all spinal TB. It includes atlantoaxial TB and sub-axial TB. As the literature evidence on this subject is scarce, majority of issues concerning CTB are still controversial. The current narrative review comprehensively discusses the various aspects related to CTB. Literature search: An elaborate search was made using keywords cervical tuberculosis, atlantoaxial tuberculosis, sub-axial tuberculosis, and cervico-thoracic tuberculosis, on pubmed and google (scholar.google.com) databases on 2 December 2020. We identified crucial questions regarding CTB and included relevant articles pertaining to them.

RESULTS

The initial search using keywords cervical tuberculosis, atlantoaxial tuberculosis, sub-axial tuberculosis, and cervico-thoracic tuberculosis yielded 4128, 76, 3 and 9 articles on 'pubmed' database, respectively. A similar search using the aforementioned keywords yielded 1,96,000, 2130, 117 and 728 articles on 'google scholar' database. The initial screening resulted in the identification of 178 articles. Full manuscripts were obtained for these articles and thoroughly scrutinised at the second stage. Review articles, randomised controlled trials and level 1 studies were given preference. Overall, 41 articles were included.

CONCLUSION

AATB and SACTB constitute 0.3 to 1% and 3% of spinal TB, respectively. The incidence of neuro-deficit in CTB is significantly more than other spinal TB. The general principles of management of CTB are similar to spinal TB elsewhere and medical therapy remains the cornerstone. Surgery is advocated in specific scenarios involving gross neuro-deficit, later stages of disease with significant bony/ligamentous disruptions, altered sagittal balance, drug resistance, and poor response to medications. The surgical approaches for AATB include anterior-alone, posterior-alone and combined approaches, although posterior access is the most preferred. Most of the studies on SACTB have supported the role of anterior approach. Additionally, posterior stabilisation may be necessary in specific scenarios. The overall long-term outcome in CTB is favourable.

[CT spectral curve in differentiating spinal tumor metastasis and infections]

OBJECTIVE

To evaluate the value of CT spectral curve in differentiating spinal tumor metastasis (STM) from spinal infections (SI).

METHODS

In the study, 29 STM and 18 SI patients proved pathologically and clinically were examined by dual energy spectral CT (DESCT). The monochromatic images and CT spectral curves were generated automatically by GSI Viewer software. The attenuation values at different energy levels (40-140 keV, every 10 keV), the attenuation values of the lesions on the conventional polychromatic CT images and the gradients of the curve were calculated and compared between STM and SI.

RESULTS

The median age of STM and SI (58 years vs. 64 years) were not significantly different (U=171, P=0.4). The attenuation values of STM at 40-100 keV were 281.79 (143.67, 446.19) HU, 199.68 (100.04, 321.49) HU, 151.54 (81.47, 243.49) HU, (122.64±27.72) HU, (99.90±23.88) HU, (85.82±21.61) HU, and (75.94±20.27) HU, respectively, which were significantly higher than SI: 185.29 (164.19, 277.03) HU, 138.44 (124.98, 238.56) HU, 105.46 (92.94, 169.53) HU, (93.77±15.55) HU, (79.15±12.84) HU, (68.99±11.75) HU, and (62.22±11.71) HU (all P < 0.05). The attenuation values at 110-140 keV and the attenuation value on the conventional CT images were not significantly different between STM and SI. The gradient of CT spectral curve of STM was 2.43±0.58, which was higher than the value of 1.50±0.40 for SI (P < 0.001). Using 1.72 and 248.80 HU as the threshold value for CT spectral curve slope and the attenuation value at 40 keV, could obtain the area under receiver operating characteristic (ROC) curve of 0.905 and 0.892, sensitivity of 88.0% and 80.0%, and specificity of 76.9% and 92.3%.

CONCLUSION

CT spectral curve provides valuable semi-quantitative information for the differential diagnosis of STM and SI, which can be used as a supplement to traditional CT imaging.

Development and Validation of a Scoring System for Differential Diagnosis of Tuberculosis and Metastatic Tumor in the Spine

Purpose

Spinal tuberculosis (TB) and metastatic tumor (MT) are common diseases with similar manifestations. Although pathological evaluation is the gold standard to confirm diagnosis, performing biopsies in all patients is not feasible. This study is aimed to create a scoring system to facilitate the differential diagnosis of spinal TB and MT before invasive procedures.

Methods

Altogether, 447 patients with spinal TB (n=198) and MT (n=249) were retrospectively analyzed. Patients were randomly assigned at 2:1 ratio to a training cohort and a validation cohort. Clinical, laboratory, and radiological diagnostic factors were identified by χ² and multiple logistic regression analyses. The scoring system was then established based on the identified independent diagnostic factors scored by regression coefficient β value, with the cut-off value being determined by ROC curve. The sensitivity and specificity of the system was calculated by comparing the predicted diagnosis with their actual pathological diagnosis.

Results

This scoring system was composed of 5 items: pain worsens at night (0 or 2 points), CRP value (0 or 3 points), tumor marker values (0 or 2 points), skip lesions (0 or 3 points), and intervertebral space destruction (0 or 3 points). Patients scoring higher than 7.5 could be diagnosed as spinal TB, otherwise, MT. According to the internal validation, the sensitivity and specificity of the system were 87.9% and 91.6%, respectively.

Conclusion

This study established and validated a scoring system which could be used to differentiate spinal TB from MT, thus helping clinicians in quick and accurate differential diagnosis.

Rapid-kilovoltage-switching dual-energy computed tomography (CT) for differentiating spinal osteolytic metastases from spinal infections

Background

Rapid-kilovoltage-switching dual-energy computed tomography (RDECT) is a non-invasive, alternative technique for quantitative diagnosis. This study aimed to investigate the value of RDECT for differentiating spinal osteolytic metastases (SOM) from spinal infections (SIs).

Methods

RDECT was performed on 29 patients with SOM and 18 patients with SIs. Both iodine-based and water-based material decomposition images were generated from the spectral CT scan. The iodine/water densities of lesions on iodine/water material-decomposition images and the CT attenuation values on traditional CT images were measured three times at different image levels, and the averages were calculated. The lesion-to-muscle ratio (LMR) and lesion-to-artery ratio (LAR) for iodine density measurements were calculated. All parameters were compared between the two groups using the two-tailed Student's t-test. A P value <0.05 was considered statistically significant. The sensitivity and specificity for differentiating SOM from SIs were determined using receiver operating characteristic curves (ROC).

Results

Iodine density, LMR, and LAR during the arterial phase (AP) and venous phase (VP) were all significantly higher for SOM than for SIs (all P<0.05). The water densities and traditional CT attenuation values during the AP and VP were not significantly different between the two groups. For ROC analysis, LAR during the VP (LAR_VP) showed the best diagnostic performance, with an area under the ROC curve (AUC) value of 0.862. When the LARVP was 0.54, the sensitivity was 82.80% and the specificity was 77.80% for differentiating SOM from SIs.

Conclusions

RDECT can provide additional information that may be useful for differentiating atypical SOM from SIs.

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.

Evaluate the characteristics and clinical significance of "toxic twin-leaf" sign in spinal epidural metastases before percutaneous vertebroplasty

Objective

Our study aimed to analyze morphological features of spinal epidural metastases using magnetic resonance imaging (MRI) and investigate the formation mechanism and clinical significance of the “toxic twin-leaf” sign in spinal epidural metastasis.

Materials and methods

We retrospectively studied 108 patients with spinal epidural metastases who underwent MRI. Patients were divided into “toxic twin-leaf” sign group (group A) and irregular group (group B). Chi-square test was used to analyze data on sex, vertebra location, presence of fracture in the corresponding vertebral body, involvement of the corresponding pedicle, and the primary tumor. Further, group data were analyzed using the rank sum test; p ​< ​0.05 was considered significant.

Results

The “twin-leaf” sign was noted in 88 cases with 136 epidural masses and 20 cases of irregular shape in 108 patients; the “toxic twin-leaf” sign accounted for 87.18% of spinal epidural metastases. A difference between groups in the vertebra location (p ​< ​0.01) was observed, but no differences were found in sex, presence of fractures in the corresponding vertebral body, involvement of the corresponding pedicle, and primary tumor (p ​> ​0.05). Intergroup differences in the rate of spinal stenosis on axial and sagittal images were significant.

Conclusions

MRI axial sequences clearly revealed the morphology of spinal epidural metastases. Detection of the “toxic twin-leaf” sign in spinal epidural metastases was of great clinical significance. Furthermore, determining the degree of spinal stenosis in the axial sequence provided a more accurate evaluation of patients’ condition compared to the sagittal sequence.

Diagnosis of spinal lesions using perfusion parameters measured by DCE-MRI and metabolism parameters measured by PET/CT

PURPOSE

To investigate the correlation of parameters measured by dynamic-contrast-enhanced MRI (DCE-MRI) and ¹⁸F-FDG PET/CT in spinal tumors, and their role in differential diagnosis.

METHODS

A total of 49 patients with pathologically confirmed spinal tumors, including 38 malignant, six benign and five borderline tumors, were analyzed. The MRI and PET/CT were done within 3 days, before biopsy. On MRI, the ROI was manually placed on area showing the strongest enhancement to measure pharmacokinetic parameters K^trans and k_ep. On PET, the maximum standardized uptake value SUV_max was measured. The parameters in different histological groups were compared. ROC was performed to differentiate between the two largest subtypes, metastases and plasmacytomas. Spearman rank correlation was performed to compare DCE-MRI and PET/CT parameters.

RESULTS

The K^trans, k_ep and SUV_max were not statistically different among malignant, benign and borderline groups (P = 0.95, 0.50, 0.11). There was no significant correlation between K^trans and SUV_max (r = - 0.20, P = 0.18), or between k_ep and SUV_max (r = - 0.16, P = 0.28). The k_ep was significantly higher in plasmacytoma than in metastasis (0.78 ± 0.17 vs. 0.61 ± 0.18, P = 0.02); in contrast, the SUV_max was significantly lower in plasmacytoma than in metastasis (5.58 ± 2.16 vs. 9.37 ± 4.26, P = 0.03). In differential diagnosis, the AUC of k_ep and SUV_max was 0.79 and 0.78, respectively.

CONCLUSIONS

The vascular parameters measured by DCE-MRI and glucose metabolism measured by PET/CT from the most aggressive tumor area did not show a significant correlation. The results suggest they provide complementary information reflecting different aspects of the tumor, which may aid in diagnosis of spinal lesions. These slides can be retrieved under Electronic Supplementary Material.

Imaging of the spine: Where do we stand?

The number of patients presenting with spine-related problems has globally increased, with an enormous growing demand for the use of medical imaging to address this problem. The last three decades witnessed great leaps for diagnostic imaging modalities, including those exploited for imaging the spine. These developments improved our diagnostic capabilities in different spinal pathologies, especially with multi-detector computed tomography and magnetic resonance imaging, via both hardware and software improvisations. Nowadays, imaging may depict subtle spinal instability caused by various osseous and ligamentous failures, and could elucidate dynamic instabilities. Consequently, recent diagnostic modalities can discern clinically relevant spinal canal stenosis. Likewise, improvement in diagnostic imaging capabilities revolutionized our understanding of spinal degenerative diseases via quantitative biomarkers rather than mere subjective perspectives. Furthermore, prognostication of spinal cord injury has become feasible, and this is expected to be translated into better effective patient tailoring to management plans with better clinical outcomes. Meanwhile, our confidence in diagnosing spinal infections and assessing the different spinal instrumentation has greatly improved over the past few last decades. Overall, revolutions in diagnostic imaging over the past few decades have upgraded spinal imaging from simple subjective and qualitative indices into a more sophisticated yet precise era of objective metrics via deploying quantitative imaging biomarkers.

Differentiation of spinal metastases originated from lung and other cancers using radiomics and deep learning based on DCE-MRI

PURPOSE

To differentiate metastatic lesions in the spine originated from primary lung cancer and other cancers using radiomics and deep learning, compared to traditional hot-spot ROI analysis.

METHODS

In a retrospective review of clinical spinal MRI database with a dynamic contrast enhanced (DCE) sequence, a total of 61 patients without prior cancer diagnosis and later confirmed to have metastases (30 lung; 31 non-lung cancers) were identified. For hot-spot analysis, a manual ROI was placed to calculate three heuristic parameters from the wash-in, maximum, and wash-out phases in the DCE kinetics. For each case, the 3D tumor mask was generated by using the normalized-cut algorithm. Radiomics analysis was performed to extract histogram and texture features from three DCE parametric maps. Deep learning was performed using these maps as inputs into a conventional convolutional neural network (CNN), as well as using all 12 sets of DCE images into a convolutional long short term memory (CLSTM) network.

RESULTS

For hot-spot ROI analysis, mean wash-out slope was 0.25 ± 10% for lung metastases and -9.8 ± 12.9% for other tumors. CHAID classification using a wash-out slope of -6.6% followed by wash-in enhancement ratio of 98% achieved a diagnostic accuracy of 0.79. Radiomics analysis using features representing tumor heterogeneity only reached the highest accuracy of 0.71. Classification using CNN achieved a mean accuracy of 0.71 ± 0.043, whereas a CLSTM improved accuracy to 0.81 ± 0.034.

CONCLUSIONS

DCE-MRI machine-learning analysis methods have potential to predict lung cancer metastases in the spine, which may be used to guide subsequent workup for confirmed diagnosis.

Differentiation of breast tuberculosis and breast cancer using diffusion-weighted, T2-weighted and dynamic contrast-enhanced magnetic resonance imaging

Background

The use of multi-parametric magnetic resonance imaging (MRI) in the evaluation of breast tuberculosis (BTB).

Objectives

To evaluate the value of diffusion-weighted imaging (DWI), T2-weighted (T2W) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiating breast cancer (BCA) from BTB.

Method

We retrospectively studied images of 17 patients with BCA who had undergone pre-operative MRI and 6 patients with pathologically proven BTB who underwent DCE-MRI during January 2014 to January 2015.

Results

All patients were female, with the age range of BTB patients being 23–43 years and the BCA patients being 31–74 years. Breast cancer patients had a statistically significant lower mean apparent diffusion coefficient (ADC) value (1072.10 ± 365.14), compared to the BTB group (1690.77 ± 624.05, p = 0.006). The mean T2-weighted signal intensity (T2SI) was lower for the BCA group (521.56 ± 233.73) than the BTB group (787.74 ± 196.04, p = 0.020). An ADC mean cut-off value of 1558.79 yielded 66% sensitivity and 94% specificity, whilst the T2SI cut-off value of 790.20 yielded 83% sensitivity and 83% specificity for differentiating between BTB and BCA. The homogeneous internal enhancement for focal mass was seen in BCA patients only.

Conclusion

Multi-parametric MRI incorporating the DWI, T2W and DCE-MRI may be a useful tool to differentiate BCA from BTB.

Dynamic contrast-enhanced magnetic resonance imaging for differentiating osteomyelitis from acute neuropathic arthropathy in the complicated diabetic foot

OBJECTIVE

The main purpose of this study was to investigate the diagnostic value of dynamic contrast-enhanced MRI (DCE-MRI) in differentiating osteomyelitis from acute neuropathic arthropathy in the diabetic foot.

MATERIALS AND METHODS

This prospective study was carried out on 30 diabetic foot patients, with a mean age of 51 years. The patients all underwent clinical examinations, laboratory examinations and DCE-MRI. The DCE-MRI parameters (K^trans, K_ep and V_e) of the regions of acute neuropathic arthropathy and osteomyelitis were calculated. Receiver operating characteristic curves (ROCs) were used to identify the DCE-MRI parameters that showed the highest accuracy in differentiating the acute neuropathic arthropathy from the osteomyelitic regions. Pearson correlation coefficients were used to assess the correlations among the DCE-MRI parameters, the level of C-reactive protein (CRP) and the erythrocyte sedimentation rate (ESR).

RESULTS

The K^trans, K_ep and V_e values of the osteomyelitic regions were higher than those of the acute neuropathic arthropathy regions, and significant differences were found between the two groups (P = 0.000, P = 0.000, P = 0.000). The ROC analysis showed that K^trans and V_e performed best in differentiating osteomyelitis from acute neuropathic arthropathy, both with an area under the curve of 0.938. The Pearson correlation coefficients showed that the DCE-MRI parameters correlated significantly with the level of CRP and ESR (P = 0.000, P = 0.014, P = 0.000; P = 0.000, P = 0.000, P = 0.013).

CONCLUSIONS

Our results showed that DCE-MRI may provide reproducible parameters that can reliably differentiate osteomyelitis from acute neuropathic arthropathy.

Role of percutaneous transpedicular biopsy in diagnosis of spinal tuberculosis and its correlation with the clinico-radiological features

INTRODUCTION

Tuberculosis (TB) has long been an important cause of destructive lesions of spine in India. However the scenario is fast changing with atypical presentations and increasing reports of non-tubercular conditions. This poses a great diagnostic dilemma.

AIM

The present study is aimed at evaluating the diagnostic efficacy of percutaneous transpedicular needle biopsy and the correlation of the histology with clinico-radiological features.

METHODS

Forty-one patients diagnosed of TB spine by magnetic resonance imaging (MRI) were revaluated of their clinical presentations, radiological and MRI features and underwent transpedicular needle biopsy under fluoroscopic guidance. Quality of the sample and radiological/MRI features between the tubercular and non-tubercular lesions were studied.

RESULTS

A good sample obtained in 92.7% patients. Of these 28 patients had TB, 3 non-specific inflammatory lesion and 7 with other non-tubercular conditions (3 pyogenic, 3 metastasis, 1 multiple myeloma). Statistically there is no significant difference among the TB and non-TB groups in terms of vertebral involvement and MRI features. However risk of presentation with cord compression, cord changes and neurodeficit are higher with TB spine.

CONCLUSION

It is very difficult to differentiate between tubercular and non-tubercular pathology of spine on the basis of most of the clinical and MRI features. It is more difficult in early cases without any neurodeficit. Thus histopathological confirmation is must for further management and percutaneous needle biopsy is the best option considering the simplicity and minimally invasive nature of the procedure.

Differential study of DCE-MRI parameters in spinal metastatic tumors, brucellar spondylitis and spinal tuberculosis

Objective

In the present study, spinal metastatic tumors, brucellar spondylitis and spinal tuberculosis were quantitatively analyzed using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) to assess the value of DCE-MRI in the differential diagnosis of these diseases.

Methods

Patients with brucellar spondylitis, spinal tuberculosis or a spinal metastatic tumor (30 cases of each) received conventional MRI and DCE-MRI examination. The volume transfer constant (K^trans), rate constant (K_ep), extravascular extracellular volume fraction (V_e) and plasma volume fraction (V_p) of the diseased vertebral bodies were measured on the perfusion parameter map, and the differences in these parameters between the patients were compared.

Results

For pathological vertebrae in cases of spinal metastatic tumor, brucellar spondylitis and spinal tuberculosis, respectively, the K^trans values (median ± quartile pitch) were 0.989±0.014, 0.720±0.011 and 0.317±0.005 min^–1; the K_ep values were 2.898±0.055, 1.327±0.017 and 0.748±0.006 min^–1; the V_e values were 0.339±0.008, 0.542±0.013 and 0.428±0.018; the V_p values were 0.048±0.008, 0.035±0.004 and 0.028±0.009; the corresponding H values were 50.25 (for K^trans), 52.47 (for K_ep), 48.33 (for V_e) and 46.56 (for V_p), and all differences were statistically significant (two-sided P<0.05).

Conclusions

The quantitative analysis of DCE-MRI has a certain value in the differential diagnosis of spinal metastatic tumor, brucellar spondylitis and spinal tuberculosis.

MRI protocol optimization for quantitative DCE-MRI of the spine

PURPOSE

In this study we systematically investigated different Dynamic Contrast Enhancement (DCE)-MRI protocols in the spine, with the goal of finding an optimal protocol that provides data suitable for quantitative pharmacokinetic modelling (PKM).

MATERIALS AND METHODS

In 13 patients referred for MRI of the spine, DCE-MRI of the spine was performed with 2D and 3D MRI protocols on a 3T Philips Ingenuity MR system. A standard bolus of contrast agent (Dotarem - 0.2ml/kg body weight) was injected intravenously at a speed of 3ml/s. Different techniques for acceleration and motion compensation were tested: parallel imaging, partial-Fourier imaging and flow compensation. The quality of the DCE MRI images was scored on the basis of SNR, motion artefacts due to flow and respiration, signal enhancement, quality of the T₁ map and of the arterial input function, and quality of pharmacokinetic model fitting to the extended Tofts model.

RESULTS

Sagittal 3D sequences are to be preferred for PKM of the spine. Acceleration techniques were unsuccessful due to increased flow or motion artefacts. Motion compensating gradients failed to improve the DCE scans due to the longer echo time and the T₂* decay which becomes more dominant and leads to signal loss, especially in the aorta. The quality scoring revealed that the best method was a conventional 3D gradient-echo acquisition without any acceleration or motion compensation technique. The priority in the choice of sequence parameters should be given to reducing echo time and keeping the dynamic temporal resolution below 5s. Increasing the number of acquisition, when possible, helps towards reducing flow artefacts. In our setting we achieved this with a sagittal 3D slab with 5 slices with a thickness of 4.5mm and two acquisitions.

CONCLUSION

The proposed DCE protocol, encompassing the spine and the descending aorta, produces a realistic arterial input function and dynamic data suitable for PKM.

Assessment of paraspinal neurogenic tumors with diffusion-weighted MR imaging

PURPOSE

To assess paraspinal neurogenic tumors with diffusion-weighted MR imaging.

METHODS

Retrospective analysis was done upon 34 patients with paraspinal neurogenic tumors that underwent diffusion-weighted MR imaging. The ADC values of the mediastinal neurogenic tumors were calculated and correlated with biopsy results.

RESULTS

The ADC of benign paraspinal neurogenic tumors (1.5 ± 0.28 × 10^-3 mm²/s) was significantly higher (P = 0.001) than that of malignant peripheral nerve sheath tumors (0.995 ± 0.198 × 10^-3 mm²/s). Selection of 1.15 × 10^-3 mm²/s as a cut-off point for differentiating malignant from benign neurogenic tumors revealed an area under the curve of 0.885, an accuracy of 91.1%, a sensitivity of 90.9%, and specificity of 91.3%. There was significant difference (P = 0.04) in the ADC of schwannomas (1.55 ± 0.29 × 10^-3 mm²/s) from neurofibromas (1.33 ± 0.08 × 10^-3 mm²/s). The cut-off ADC value of 1.44 × 10^-3 mm²/s was used to differentiate schwannomas and neurofibromas with an area under the curve of 0.86, an accuracy of 82.6%, a sensitivity of 100%, and a specificity of 76.5%.

CONCLUSION

Diffusion-weighted MR imaging is imaging parameter that can be used for differentiation of benign from malignant paraspinal neurogenic tumors.

Diagnosis of Spinal Lesions Using Heuristic and Pharmacokinetic Parameters Measured by Dynamic Contrast-Enhanced MRI

RATIONALE AND OBJECTIVES

This study aimed to evaluate the diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in differentiation of four spinal lesions by using heuristic and pharmacokinetic parameters analyzed from DCE signal intensity time course.

MATERIALS AND METHODS

DCE-MRI of 62 subjects with confirmed myeloma (n = 9), metastatic cancer (n = 22), lymphoma (n = 7), and inflammatory tuberculosis (TB) (n = 24) in the spine were analyzed retrospectively. The region of interest was placed on strongly enhanced tissues. The DCE time course was categorized as the "wash-out," "plateau," or "persistent enhancement" pattern. The maximum enhancement, steepest wash-in enhancement, and wash-out slope using the signal intensity at 67 seconds after contrast injection as reference were measured. The Tofts 2-compartmental pharmacokinetic model was applied to obtain K^trans and k_ep. Pearson correlation between heuristic and pharmacokinetic parameters was evaluated, and receiver operating characteristic curve analysis was performed for pairwise group differentiation.

RESULTS

The mean wash-out slope was -22% ± 10% for myeloma, 1% ± 0.4% for metastatic cancer, 3% ± 3% for lymphoma, and 7% ± 10% for TB, and it could significantly distinguish myeloma from metastasis (area under the curve [AUC] = 0.884), lymphoma (AUC = 1.0), and TB (AUC = 1.0) with P = .001, and distinguish metastasis from TB (AUC = 0.741) with P = .005. The k_ep and wash-out slope were highly correlated (r = 0.92), and they showed a similar diagnostic performance. The K^trans was significantly correlated with the maximum enhancement (r = 0.71) and the steepest wash-in enhancement (r = 0.85), but they had inferior diagnostic performance compared to the wash-out slope.

CONCLUSIONS

DCE-MRI may provide additional diagnostic information, and a simple wash-out slope had the best diagnostic performance. The heuristic and pharmacokinetic parameters were highly correlated.

Morphological and dynamic contrast enhanced MR imaging features for the differentiation of chordoma and giant cell tumors in the Axial Skeleton

PURPOSE

To characterize the morphological and dynamic-contrast-enhanced (DCE) MRI features of chordoma and giant cell tumor (GCT) of bone occurring in the axial skeleton.

MATERIALS AND METHODS

A total of 13 patients with chordoma and 26 patients with GCT who received conventional T1, T2, and DCE-MRI on 3 Tesla MR scanners were retrospectively identified and analyzed. Two radiologists evaluated morphological features independently, including the lesion location, expansile bone changes, vertebral compression, presence of paraspinal soft tissue mass, fibrous septa, and the signal intensity on T1WI and T2WI. The inter-observer agreement was evaluated by kappa test. The DCE kinetics was measured to obtain the initial area under curve (IAUC) and the wash-out slope; also the two-compartmental pharmacokinetic model was applied to obtain K^trans and k_ep . The diagnostic accuracy was evaluated by CHAID decision tree and ROC analysis.

RESULTS

Chordomas were more likely to show soft tissue mass than GCTs (13/13 = 100% versus 15/26 = 58%; P = 0.007), as well as fibrous septa (9/13 = 69% versus 0; P < 0.001). In decision tree analysis, presence of fibrous septa and lesion location yield 31/39 = 79% accuracy. The DCE-MRI pharmacokinetic parameters K^trans and k_ep of GCTs were significantly higher than those of chordomas, 0.13 ± 0.65 versus 0.06 ± 0.04 (1/min) for K^trans , 0.62 ± 0.22 versus 0.17 ± 0.12 (1/min) for k_ep , P < 0.001 for both. If using kep = 0.43/min as the cut-off value, it achieved 100% sensitivity and 92% specificity to differentiate chordoma from GCT, with an overall accuracy of 37/39 = 95%. The IAUC was highly correlated with K^trans (r = 0.94), and the slope was highly correlated with k_ep (r = 0.95).

CONCLUSION

Several morphological features were significantly different between chordoma and GCT, but their diagnostic performance was inferior to that of DCE-MRI.

LEVEL OF EVIDENCE

4 J. Magn. Reson. Imaging 2017;45:1068-1075.