Impact of SUSAN Denoising and ComBat Harmonization on Machine Learning Model Performance for Malignant Brain Neoplasms

BACKGROUND AND PURPOSE

Feature variability in radiomics studies due to technical and magnet strength parameters is well known and may be addressed through various pre-processing methods. However, very few studies have evaluated downstream impact of variable pre-processing on model classification performance in a multi-class setting. We sought to evaluate the impact of SUSAN denoising and ComBat harmonization on model classification performance.

MATERIALS AND METHODS

A total of 493 cases (410 internal and 83 external dataset) of glioblastoma (GB), intracranial metastatic disease (IMD) and primary CNS lymphoma (PCNSL) underwent semi-automated 3D-segmentation post baseline image processing (BIP) consisting of resampling, realignment, co-registration, skull stripping and image normalization. Post BIP, two sets were generated, one with and another without SUSAN denoising (SD). Radiomics features were extracted from both datasets and batch corrected to produce four datasets: (a) BIP, (b) BIP with SD, (c) BIP with ComBat and (d) BIP with both SD and ComBat harmonization. Performance was then summarized for models using a combination of six feature selection techniques and six machine learning models across four mask-sequence combinations with features derived from one-three (multi-parametric) MRI sequences.

RESULTS

Most top performing models on the external test set used BIP+SD derived features. Overall, use of SD and ComBat harmonization led to a slight but generally consistent improvement in model performance on the external test set.

CONCLUSIONS

The use of image pre-processing steps such as SD and ComBat harmonization may be more useful in a multiinstitutional setting and improve model generalizability. Models derived from only T1-CE images showed comparable performance to models derived from multiparametric MRI.

High-Grade Astrocytoma with Piloid Features: A Dual Institutional Review of Imaging Findings of a Novel Entity

High-grade astrocytoma with piloid features (HGAP) is a recently identified brain tumor characterized by a distinct DNA methylation profile. Predominantly located in the posterior fossa of adults, HGAP is notably prevalent in individuals with neurofibromatosis type 1. We present an image-centric review of HGAP and explore the association between HGAP and neurofibromatosis type 1. Data were collected from 8 HGAP patients treated at two tertiary care institutions between January 2020 and October 2023. Demographic details, clinical records, management, and tumor molecular profiles were analyzed. Tumor characteristics, including location and imaging features on MR imaging, were reviewed. Clinical or imaging features suggestive of neurofibromatosis 1 or the presence of NF1 gene alteration were documented. The mean age at presentation was 45.5 years (male/female = 5:3). Tumors were midline, localized in the posterior fossa (n = 4), diencephalic/thalamic (n = 2), and spinal cord (n = 2). HGAP lesions were T1 hypointense, T2-hyperintense, mostly without diffusion restriction, predominantly peripheral irregular enhancement with central necrosis (n = 3) followed by mixed heterogeneous enhancement (n = 2). Two NF1 mutation carriers showed signs of neurofibromatosis type 1 before HGAP diagnosis, with one diagnosed during HGAP evaluation, strengthening the HGAP-NF1 link, particularly in patients with posterior fossa masses. All tumors were IDH1 wild-type, often with ATRX, CDKN2A/B, and NF1 gene alteration. Six patients underwent surgical resection followed by adjuvant chemoradiation. Six patients were alive, and two died during the last follow-up. Histone H3 mutations were not detected in our cohort, such as the common H3K27M typically seen in diffuse midline gliomas, linked to aggressive clinical behavior and poor prognosis. HGAP lesions may involve the brain or spine and tend to be midline or paramedian in location. Underlying neurofibromatosis type 1 diagnosis or imaging findings are important diagnostic cues.

Molecular GBM versus Histopathological GBM: Radiology-Pathology-Genetic Correlation and the New WHO 2021 Definition of Glioblastoma

Given the recent advances in molecular pathogenesis of tumors, with better correlation with tumor behavior and prognosis, major changes were made to the new 2021 WHO (CNS5) classification of CNS tumors, including updated criteria for diagnosis of glioblastoma. Diagnosis of GBM now requires absence of isocitrate dehydrogenase and histone 3 mutations (IDH-wildtype and H3-wildtype) as the basic cornerstone, with elimination of the IDH-mutated category. The requirements for diagnosis were conventionally histopathological, based on the presence of pathognomonic features such as microvascular proliferation and necrosis. However, even if these histological features are absent, many lower grade (WHO grade 2/3) diffuse astrocytic gliomas behave clinically similar to GBM (grade 4). The 2021 WHO classification introduced new molecular criteria that can be used to upgrade the diagnosis of such histologically lower-grade, IDH-wildtype, astrocytomas to GBM. The three molecular criteria include: concurrent gain of whole chromosome 7 and loss of whole chromosome 10 (+7/-10); TERT promoter mutation; epidermal growth factor receptor (EGFR) amplification. Given these changes, it is now strongly recommended to have molecular analysis of WHO grade 2/3 diffuse astrocytic, IDH-wildtype, gliomas in adult patients, as identification of any of the above mutations allows for upgrading the tumor to WHO grade 4 ("molecular GBM") with important prognostic implications. Despite at an early stage, there is active ongoing research on the unique MRI features of molecular GBM. This paper highlights the differences between "molecular" and "histopathological" GBM, with the aim of providing a basic understanding about these changes.ABBREVIATIONS: GBM=Glioblastoma; TERT=telomerase reverse transcriptase; EGFR=epidermal growth factor receptor; MGMT= methylguanine-DNA methyltransferase; NGS= next-generation sequencing; IDH= isocitrate dehydrogenase.

Newly Recognized Genetic Tumor Syndromes of the CNS in the 5th WHO Classification: Imaging Overview with Genetic Updates

The nervous system is commonly involved in a wide range of genetic tumor-predisposition syndromes. The classification of genetic tumor syndromes has evolved during the past years; however, it has now become clear that these syndromes can be categorized into a relatively small number of major mechanisms, which form the basis of the new 5th edition of the World Health Organization book (beta online version) on genetic tumor syndromes. For the first time, the World Health Organization has also included a separate chapter on genetic tumor syndromes in the latest edition of all the multisystem tumor series, including the 5th edition of CNS tumors. Our understanding of these syndromes has evolved rapidly since the previous edition (4th edition, 2016) with recognition of 8 new syndromes, including the following: Elongator protein complex-medulloblastoma syndrome, BRCA1-associated protein 1 tumor-predisposition syndrome, DICER1 syndrome, familial paraganglioma syndrome, melanoma-astrocytoma syndrome, Carney complex, Fanconi anemia, and familial retinoblastoma. This review provides a description of these new CNS tumor syndromes with a focus on imaging and genetic characteristics.

Cauda equina neuroendocrine tumors: A single institutional imaging review of cases over two decades

Cauda Equina Neuroendocrine Tumors (CE-NET), previously referred to as paragangliomas are a rare subset of spinal tumors, with limited data on imaging. Herein, we present a retrospective review of clinical and imaging findings of CE-NETs in ten patients who were evaluated at our institution over the past two decades. All patients had well-defined intradural lesions in the lumbar spine which demonstrated slow growth. A review of imaging findings revealed the presence of an eccentric vascular pedicle along the dorsal aspect of the tumor in 8 of the 10 patients (eccentric vessel sign), a distinctive finding that has not previously been reported with this tumor and may help improve the accuracy of imaging-based diagnosis. In all cases, a gross-total resection was performed, with resolution of symptoms in most of the cases.

Differentiation Between Glioblastoma and Metastatic Disease on Conventional MRI Imaging Using 3D-Convolutional Neural Networks: Model Development and Validation

RATIONALE AND OBJECTIVES

Imaging-based differentiation between glioblastoma (GB) and brain metastases (BM) remains challenging. Our aim was to evaluate the performance of 3D-convolutional neural networks (CNN) to address this binary classification problem.

MATERIALS AND METHODS

T1-CE, T2WI, and FLAIR 3D-segmented masks of 307 patients (157 GB and 150 BM) were generated post resampling, co-registration normalization and semi-automated 3D-segmentation and used for internal model development. Subsequent external validation was performed on 59 cases (27 GB and 32 BM) from another institution. Four different mask-sequence combinations were evaluated using area under the curve (AUC), precision, recall and F1-scores. Diagnostic performance of a neuroradiologist and a general radiologist, both without and with the model output available, was also assessed.

RESULTS

3D-model using the T1-CE tumor mask (TM) showed the highest performance [AUC 0.93 (95% CI 0.858-0.995)] on the external test set, followed closely by the model using T1-CE TM and FLAIR mask of peri-tumoral region (PTR) [AUC of 0.91 (95% CI 0.834-0.986)]. Models using T2WI masks showed robust performance on the internal dataset but lower performance on the external set. Both neuroradiologist and general radiologist showed improved performance with model output provided [AUC increased from 0.89 to 0.968 (p = 0.06) and from 0.78 to 0.965 (p = 0.007) respectively], the latter being statistically significant.

CONCLUSION

3D-CNNs showed robust performance for differentiating GB from BMs, with T1-CE TM, either alone or combined with FLAIR-PTR masks. Availability of model output significantly improved the accuracy of the general radiologist.

Clinical and Magnetic Resonance Imaging Radiomics-Based Survival Prediction in Glioblastoma Using Multiparametric Magnetic Resonance Imaging

INTRODUCTION

Survival prediction in glioblastoma remains challenging, and identification of robust imaging markers could help with this relevant clinical problem. We evaluated multiparametric magnetic resonance imaging-derived radiomics to assess prediction of overall survival (OS) and progression-free survival (PFS).

METHODOLOGY

A retrospective, institutional review board-approved study was performed. There were 93 eligible patients, of which 55 underwent gross tumor resection and chemoradiation (GTR-CR). Overall survival and PFS were assessed in the entire cohort and the GTR-CR cohort using multiple machine learning pipelines. A model based on multiple clinical variables was also developed. Survival prediction was assessed using the radiomics-only, clinical-only, and the radiomics and clinical combined models.

RESULTS

For all patients combined, the clinical feature-derived model outperformed the best radiomics model for both OS (C-index, 0.706 vs 0.597; P < 0.0001) and PFS prediction (C-index, 0.675 vs 0.588; P < 0.001). Within the GTR-CR cohort, the radiomics model showed nonstatistically improved performance over the clinical model for predicting OS (C-index, 0.638 vs 0.588; P = 0.4). However, the radiomics model outperformed the clinical feature model for predicting PFS in GTR-CR cohort (C-index, 0.641 vs 0.550; P = 0.004). Combined clinical and radiomics model did not yield superior prediction when compared with the best model in each case.

CONCLUSIONS

When considering all patients, regardless of therapy, the radiomics-derived prediction of OS and PFS is inferior to that from a model derived from clinical features alone. However, in patients with GTR-CR, radiomics-only model outperforms clinical feature-derived model for predicting PFS.

Update from the 5th Edition of the WHO Classification of Nasal, Paranasal, and Skull Base Tumors: Imaging Overview with Histopathologic and Genetic Correlation

Sinonasal and skull base tumors are a heterogeneous group of neoplasms with considerable histologic variation and overlapping imaging features. In 2022, the World Health Organization updated the head and neck tumor classification, further emphasizing the importance of molecular data and genetic alterations in sinonasal neoplasms. The changes include the addition of new entities and discussion of emerging entities, as well as changes to the taxonomy and characterization of tumors. The new classification focuses on entities that develop in these sites either exclusively (eg, olfactory neuroblastoma) or most frequently. Another change includes reduction in the number of categories by creating separate category-specific chapters for soft-tissue, hematolymphoid, and neuroectodermal lesions. In this review, we briefly discuss the various categories in the new classification with a more detailed description of the 2 new entities (SWItch/Sucrose Non-Fermentable complex-deficient sinonasal carcinomas and human papillomavirus-related multiphenotypic sinonasal carcinoma). We also highlight the emerging entities including IDH-mutant sinonasal malignancies and DEK-AFF2 carcinoma, presently classified as sinonasal undifferentiated carcinoma and nonkeratinizing squamous cell carcinoma, respectively.

Radiological abnormalities in progressive multifocal leukoencephalopathy: Identifying typical and atypical imaging patterns for early diagnosis and differential considerations

Progressive multifocal leukoencephalopathy (PML) is a rare viral central nervous system (CNS) demyelinating disease primarily associated with a compromised immune system. PML is seen mainly in individuals with human immunodeficiency virus, lymphoproliferative disease, and multiple sclerosis. Patients on immunomodulators, chemotherapy, and solid organ or bone marrow transplants are predisposed to PML. Recognition of various PML-associated typical and atypical imaging abnormalities is critical for early diagnosis and differentiating it from other conditions, especially in high-risk populations. Early PML recognition should expedite efforts at immune-system restoration, allowing for a favorable outcome. This review aims to provide a practical overview of radiological abnormalities in PML patients and address differential considerations.

Unpacking the CNS Manifestations of Epstein-Barr Virus: An Imaging Perspective

Epstein-Barr virus is a ubiquitous herpesvirus that may cause both infective (encephalitis, meningitis, and so forth) and postinfection inflammatory (such as Guillain-Barré syndrome, acute disseminated encephalomyelitis) manifestations in the CNS. Diagnosis of Epstein-Barr virus-related CNS pathologies is often complicated due to a nonspecific clinical presentation and overlap with other infectious and noninfectious causes, both clinically and on imaging. The Epstein-Barr virus is also implicated in several lymphoproliferative disorders in both immunocompromised and immunocompetent hosts. MR imaging is preferred for evaluating the extent of involvement and monitoring therapy response, given its high sensitivity and specificity, though imaging findings may be nonspecific. Herein, we review the imaging spectrum of Epstein-Barr virus-associated CNS disorders.

AI-based classification of three common malignant tumors in neuro-oncology: A multi-institutional comparison of machine learning and deep learning methods

PURPOSE

To determine if machine learning (ML) or deep learning (DL) pipelines perform better in AI-based three-class classification of glioblastoma (GBM), intracranial metastatic disease (IMD) and primary CNS lymphoma (PCNSL).

METHODOLOGY

Retrospective analysis included 502 cases for training (208 GBM, 67 PCNSL and 227 IMD), with external validation on 86 cases (27:27:32). Multiparametric MRI images (T1W, T2W, FLAIR, DWI and T1-CE) were co-registered, resampled, denoised and intensity normalized, followed by semiautomatic 3D segmentation of the enhancing tumor (ET) and peritumoral region (PTR). Model performance was assessed using several ML pipelines and 3D-convolutional neural networks (3D-CNN) using sequence specific masks, as well as combination of masks. All pipelines were trained and evaluated with 5-fold nested cross-validation on internal data followed by external validation using multi-class AUC.

RESULTS

Two ML models achieved similar performance on test set, one using T2-ET and T2-PTR masks (AUC: 0.885, 95% CI: [0.816, 0.935] and another using T1-CE-ET and FLAIR-PTR mask (AUC: 0.878, CI: [0.804, 0.930]). The best performing DL models achieved an AUC of 0.854, (CI [0.774, 0.914]) on external data using T1-CE-ET and T2-PTR masks, followed by model derived from T1-CE-ET, ADC-ET and FLAIR-PTR masks (AUC: 0.851, CI [0.772, 0.909]).

CONCLUSION

Both ML and DL derived pipelines achieved similar performance. T1-CE mask was used in three of the top four overall models. Additionally, all four models had some mask derived from PTR, either T2WI or FLAIR.

Fibroblast Activation Protein Inhibitor-Based Radionuclide Therapies: Current Status and Future Directions

Metastatic malignancies have limited management strategies and variable treatment responses. Cancer cells develop beside and depend on the complex tumor microenvironment. Cancer-associated fibroblasts, with their complex interaction with tumor and immune cells, are involved in various steps of tumorigenesis, such as growth, invasion, metastasis, and treatment resistance. Prooncogenic cancer-associated fibroblasts emerged as attractive therapeutic targets. However, clinical trials have achieved suboptimal success. Fibroblast activation protein (FAP) inhibitor-based molecular imaging has shown encouraging results in cancer diagnosis, making them innovative targets for FAP inhibitor-based radionuclide therapies. This review summarizes the results of preclinical and clinical FAP-based radionuclide therapies. We will describe advances and FAP molecule modification in this novel therapy, as well as its dosimetry, safety profile, and efficacy. This summary may guide future research directions and optimize clinical decision-making in this emerging field.

Amino Acid Tracer PET MRI in Glioma Management: What a Neuroradiologist Needs to Know

PET with amino acid tracers provides additional insight beyond MR imaging into the biology of gliomas that can be used for initial diagnosis, delineation of tumor margins, planning of surgical and radiation therapy, assessment of residual tumor, and evaluation of posttreatment response. Hybrid PET MR imaging allows the simultaneous acquisition of various PET and MR imaging parameters in a single investigation with reduced scanning time and improved anatomic localization. This review aimed to provide neuroradiologists with a concise overview of the various amino acid tracers and a practical understanding of the clinical applications of amino acid PET MR imaging in glioma management. Future perspectives in newer advances, novel radiotracers, radiomics, and cost-effectiveness are also outlined.

A review of Punarnava’s pharmacological profile focusing on its beneficial and adverse effects

Background:

Punarnava is recognized as an essential remedy because it treats a wide range of health problems. It is commonly known as a rejuvenator. Its chemical constituents are all responsible for pharmacological activity in the body in some ways. There is a lot of evidence that the leaves, stems, and roots can be used as medicine.

Objective:

The morphological, chemical, and pharmacological characteristics of Boerhaavia diffusa are discussed in this article. The purpose of this review is to discuss the pharmacological profile of Punarnava and its chemical elements, as well as the benefits and drawbacks of its steroidal component β-Ecdysone.

Method:

This article compiled information by reviewing a variety of published articles and research papers from several sources, including Research Gate, WJPRT, IJPSM, Elsevier, Taylor & Francis, Springer Nature, and The Journal of Ayurveda and Integrated Medicine.

Result:

It is a widely used remedy for numerous ailments among diverse cultural groups, Ayurvedic, and traditional practitioners. To some extent, it is used in a variety of formulations to treat sciatica, cancer, immunomodulation, obesity, diabetes, jaundice, inflammation, asthma, rheumatism, nephrological difficulties, ascites, anemia, and gynaecological disorders.

Conclusion:

Herbal medications are becoming increasingly popular nowadays. Punarnava is one of the most beneficial herbs available. More analysis is needed to investigate the impacts of each chemical ingredient in Punarnava. β-Ecdysone is a key component of Punarnava, which is both beneficial and detrimental to humans in different ways. Hence, further research is also needed to emphasize the impacts of each Punarnava chemical ingredient.

CT Perfusion Maps Improve Detection of M2-MCA Occlusions in Acute Ischemic Stroke

OBJECTIVES

Middle cerebral artery occlusions, particularly M2 branch occlusions are challenging to identify on CTA. We hypothesized that additional review of the CTP maps will increase large vessel occlusion (LVO) detection accuracy on CTA and reduce interpretation time.

MATERIALS AND METHODS

Two readers (R1 and R2) retrospectively reviewed the CT studies in 99 patients (27 normal, 26 M1-MCA, 46 M2-MCA occlusions) who presented with suspected acute ischemic stroke (AIS). The time of interpretation and final diagnosis were recorded for the CTA images (derived from CTP data), both without and with the CTP maps. The time for analysis for all vascular occlusions was compared using McNemar tests. ROC curve analysis and McNemar tests were performed to assess changes in diagnostic performance with the addition of CTP maps.

RESULTS

With the addition of the CTP maps, both readers showed increased sensitivity (p = 0.01 for R1 and p = 0.04 for R2), and accuracy (p = 0.02 for R1 and p = 0.004 for R2) for M2-MCA occlusions. There was a significant improvement in diagnostic performance for both readers for detection of M2-MCA occlusions (AUC R1 = 0.86 to 0.95, R2 = 0.84 to 0.95; p < 0.05). Both readers showed reduced interpretation time for all cases combined, as well as for normal studies (p < 0.001) when CTP images were reviewed along with CTA. Both readers also showed reduced interpretation time for M2-MCA occlusions, which was significant for one of the readers (p < 0.02).

CONCLUSION

The addition of CTP maps improves accuracy and reduces interpretation time for detecting LVO and M2-MCA occlusions in AIS. Incorporation of CTP in acute stroke imaging protocols may improve detection of more distal occlusions.

Effect of Whole-body [18F]Fluoro-2-deoxy-2-d-glucose Positron Emission Tomography in Patients with Suspected Brain Metastasis

Background and Purpose [18F]Fluoro-2-deoxy-2-d-glucose (FDG) positron emission tomography/computed tomography (PET/CT) has a promising role in the workup and management of carcinoma of unknown primary (CUP). We have evaluated the effect of whole-body FDG PET/CT in assessing the patients presented with suspected brain metastasis (CUP-BM) on brain magnetic resonance imaging (MRI) or computed tomography (CT).

Materials and Methods This retrospective study included FDG PET/CT of 50 patients (24 males, mean: 58 ± 12.2 years old) with a CUP-BM diagnosis based on MRI and CT imaging. The final diagnosis of primary brain neoplasm (BP) or brain metastases (BM) was based on FDG PET/CT findings and/or histopathology (HPE).

Results On FDG PET/CT, 52% (26/50) of patients did not have any systemic lesion apart from a brain lesion. Out of these, 50% (13/26) had HPE confirmation of primary brain neoplasm (BP). FDG PET/CT identified multiple systemic lesions apart from brain lesions in the remaining 48% (24/50) of patients. They were categorized as the brain metastases (BM) group. The primary lesions were located in the lungs (n = 20), kidneys (n = 1), prostate (n = 1), esophagus (n = 1), and tongue (n = 1).

Conclusion FDG PET/CT could suggest a diagnosis of BM based on the presence of systemic lesions. It also provides an easily accessible peripheral site for biopsy and systemic disease burden in a single scan. FDG PET/CT's up-front use in suspected CUP-BM on CT and/or MRI could differentiate the BM from BP in most cases and avoid brain biopsy in the BM group.

Long-term performance of untreated fresh autologous pericardium as a valve substitute in pulmonary position

Background:

Pulmonary regurgitation is imminent after transannular patch (TAP). We analyze the long-term performance of untreated autologous pericardium (UAP) as valve substitute at pulmonary position in patients requiring TAP.

Material and Methods:

This cross-sectional study include patients operated between 2007 and 2012 (n = 92). A sample of 19 patients was selected for this study which had a follow-up of more than 3 years. This includes patients with no TAP (n = 4) and with TAP and valve substitute, a monocusp (n = 11) or a tricuspid valve (n = 4) at neopulmonary annulus. Patients underwent echocardiography for assessment of right ventricle function and 18 fluoro-deoxyglucose PET CT scan for measurements of valve substitute at neopulmonary annulus. The target to blood ratio (TBR) of uptake of glucose by monocusp was measured at the cooptation edge of the neopulmonary valve.

Results:

The median age of the patients is 14 (9 – 37). RV function is preserved (TAPSE 18.9 (10.6 – 22.8)) at a mean follow-up of 4 years (3-9). The measurements of monocusp shows a shrinkage in height of the cusp by 35.5% (70% – 1.0%) and length by 7% (-44% - +104%). There was less shrinkage observed in patients below 15 years of age. The TBR of monocusp was 0.945 (0.17 – 3.35) with a strong correlation between the TBR values of aortic valve leaflet and monocusp leaflet of same patient.

Conclusion:

The UAP is functional and successful as a valve substitute at neo pulmonary annulus at long-term follow-up. It has resisted calcification and has shown uptake of glucose in physiological limits.

Multimodality imaging in a case of multiple pulmonary hyalinizing granulomas - A decade follow-up

A 44-year-old male was referred to our clinic (2015) to evaluate multiple lung nodules with increasing fatigue, dyspnea, and weight loss. He was being assessed to an outside hospital for the same since 2010. The X-ray and computed-tomography (CT)-chest showed numerous pulmonary nodules and bilateral hilar adenopathy. Imaging workup at our institute (2015) redemonstrated extensive calcified pulmonary nodules. 18fluoro-2-deoxy-d-glucose positron emission tomographyCT showed widespread pulmonary nodules with low-grade uptake. Video-assisted thoracic surgery lung biopsy revealed pulmonary hyalinizing granuloma (PHG). Recently because of increasing symptoms, he is being evaluated for a lung transplant. This case represents a rare diagnosis of PHG with a decade follow-up.

Vascular Involvement in Neurosarcoidosis: Early Experiences From Intracranial Vessel Wall Imaging

BACKGROUND AND OBJECTIVES

Cerebrovascular manifestations in neurosarcoidosis (NS) were previously considered rare but are being increasingly recognized. We report our preliminary experience in patients with NS who underwent high-resolution vessel wall imaging (VWI).

METHODS

A total of 13 consecutive patients with NS underwent VWI. Images were analyzed by 2 neuroradiologists in consensus. The assessment included segment-wise evaluation of larger- and medium-sized vessels (internal carotid artery, M1-M3 middle cerebral artery; A1-A3 anterior cerebral artery; V4 segments of vertebral arteries; basilar artery; and P1-P3 posterior cerebral artery), lenticulostriate perforator vessels, and medullary and deep cerebral veins. Cortical veins were not assessed due to flow-related artifacts. Brain biopsy findings were available in 6 cases and were also reviewed.

RESULTS

Mean patient age was 54.9 years (33-71 years) with an M:F of 8:5. Mean duration between initial diagnosis and VWI study was 18 months. Overall, 9/13 (69%) patients had vascular abnormalities. Circumferential large vessel enhancement was seen in 3/13 (23%) patients, whereas perforator vessel involvement was seen in 6/13 (46%) patients. Medullary and deep vein involvement was also seen in 6/13 patients. In addition, 7/13 (54%) patients had microhemorrhages in susceptibility-weighted imaging, and 4/13 (31%) had chronic infarcts. On biopsy, 5/6 cases showed perivascular granulomas with vessel wall involvement in all 5 cases.

DISCUSSION

Our preliminary findings suggest that involvement of intracranial vascular structures may be a common finding in patients with NS and should be routinely looked for. These findings appear concordant with previously reported autopsy literature and need to be validated on a larger scale.

Role of FDG PET/CT for detection of primary tumor in patients with extracervical metastases from carcinoma of unknown primary

AIM

To explore the diagnostic performance of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) to detect the primary tumor site in patients with extracervical metastases from carcinoma of unknown primary (CUP). We evaluated patient outcomes as overall survival (OS).

MATERIALS AND METHODS

In a single-center, retrospective study (2005-2019), patients with extracervical metastases from CUP underwent FDG PET/CT to detect primary tumor sites. The final diagnosis was based on histopathology/or clinical follow-up of at least 12 months.

RESULTS

A total of 83 patients [Male 41 (49%), mean age 59 ± 14 years, range: 32-83 years] fulfilled the inclusion/exclusion criteria and were enrolled for analysis. The primary tumor was detected in 36 out of 83 (43%) patients based on histopathology/or clinical follow-up. PET/CT suggested the primary tumor site in 39 (47%) patients with diagnostic accuracy of 87%, sensitivity 89%, specificity 85%, PPV 82%, NPV 91% and detection rate 39%. Patients with oligometastases (<3) (2.16 years, 1.04-2.54) and primary unidentified (1 year, 0.34-2.14) had longer median survival time compared to the patients with multiple metastases (0.67 years, 0.17-1.58, p = 0.009) and primary identified (0.67 years,0.16-1.33, p = 0.002). The SUVmax of the primary or metastatic lesions with maximum uptake was not significantly related to survival.

CONCLUSIONS

PET/CT could reveal the primary tumor site in 39% of the patients. It demonstrated the metastatic disease burden and distribution in patients with 'primary obscured', which directs management. Patients with multiple metastases and primary identified had a poorer prognosis. In patients with primary unidentified after PET/CT, a further search was futile.

Machine learning based differentiation of glioblastoma from brain metastasis using MRI derived radiomics

Few studies have addressed radiomics based differentiation of Glioblastoma (GBM) and intracranial metastatic disease (IMD). However, the effect of different tumor masks, comparison of single versus multiparametric MRI (mp-MRI) or select combination of sequences remains undefined. We cross-compared multiple radiomics based machine learning (ML) models using mp-MRI to determine optimized configurations. Our retrospective study included 60 GBM and 60 IMD patients. Forty-five combinations of ML models and feature reduction strategies were assessed for features extracted from whole tumor and edema masks using mp-MRI [T1W, T2W, T1-contrast enhanced (T1-CE), ADC, FLAIR], individual MRI sequences and combined T1-CE and FLAIR sequences. Model performance was assessed using receiver operating characteristic curve. For mp-MRI, the best model was LASSO model fit using full feature set (AUC 0.953). FLAIR was the best individual sequence (LASSO-full feature set, AUC 0.951). For combined T1-CE/FLAIR sequence, adaBoost-full feature set was the best performer (AUC 0.951). No significant difference was seen between top models across all scenarios, including models using FLAIR only, mp-MRI and combined T1-CE/FLAIR sequence. Top features were extracted from both the whole tumor and edema masks. Shape sphericity is an important discriminating feature.

Multiparametric magnetic resonance imaging and positron emission tomography findings in neurodegenerative diseases: Current status and future directions

Neurodegenerative diseases (NDDs) are characterized by progressive neuronal loss, leading to dementia and movement disorders. NDDs broadly include Alzheimer's disease, frontotemporal lobar degeneration, parkinsonian syndromes, and prion diseases. There is an ever-increasing prevalence of mild cognitive impairment and dementia, with an accompanying immense economic impact, prompting efforts aimed at early identification and effective interventions. Neuroimaging is an essential tool for the early diagnosis of NDDs in both clinical and research settings. Structural, functional, and metabolic imaging modalities, including magnetic resonance imaging (MRI) and positron emission tomography (PET), are widely available. They show encouraging results for diagnosis, monitoring, and treatment response evaluation. The current review focuses on the complementary role of various imaging modalities in relation to NDDs, the qualitative and quantitative utility of newer MRI techniques, novel radiopharmaceuticals, and integrated PET/MRI in the setting of NDDs.

Glioblastoma and primary central nervous system lymphoma: differentiation using MRI derived first-order texture analysis - a machine learning study

OBJECTIVES

To evaluate the diagnostic performance of multiple machine learning classifier models derived from first-order histogram texture parameters extracted from T1-weighted contrast-enhanced images in differentiating glioblastoma and primary central nervous system lymphoma.

METHODS

Retrospective study with 97 glioblastoma and 46 primary central nervous system lymphoma patients. Thirty-six different combinations of classifier models and feature selection techniques were evaluated. Five-fold nested cross-validation was performed. Model performance was assessed for whole tumour and largest single slice using receiver operating characteristic curve.

RESULTS

The cross-validated model performance was relatively similar for the top performing models for both whole tumour and largest single slice (area under the curve 0.909-0.924). However, there was a considerable difference between the worst performing model (logistic regression with full feature set, area under the curve 0.737) and the highest performing model for whole tumour (least absolute shrinkage and selection operator model with correlation filter, area under the curve 0.924). For single slice, the multilayer perceptron model with correlation filter had the highest performance (area under the curve 0.914). No significant difference was seen between the diagnostic performance of the top performing model for both whole tumour and largest single slice.

CONCLUSIONS

T1 contrast-enhanced derived first-order texture analysis can differentiate between glioblastoma and primary central nervous system lymphoma with good diagnostic performance. The machine learning performance can vary significantly depending on the model and feature selection methods. Largest single slice and whole tumour analysis show comparable diagnostic performance.

Bartonella osteomyelitis versus vertebral sarcoidosis: A tale of two cases

BACKGROUND

Osteomyelitis is an uncommon manifestation of Bartonella henselae. Similarly, bony involvement may occur with sarcoidosis. Even though these are pathologically distinct entities, they can have overlapping imaging manifestations and therefore mimic one another. This is further complicated by the fact that both entities show non-caseating granulomatous inflammation on histopathology. We present two cases with similar imaging findings, with one case eventually diagnosed as Bartonella osteomyelitis, while the other proved to be vertebral sarcoidosis. Both patients exhibited vertebral involvement in common, and improved clinically and radiographically following antibiotics and steroids treatment, respectively. Given the overlapping pathological and imaging manifestations, and the non-specific clinical presentation, these entities may be considered in the differential consideration of each other. The presence of associated findings in such cases may be helpful.

FDG PET/CT in Neurolymphomatosis

Online supplemental material is available for this article.

Diagnostic Performance of PET and Perfusion-Weighted Imaging in Differentiating Tumor Recurrence or Progression from Radiation Necrosis in Posttreatment Gliomas: A Review of Literature

Tumor resection followed by chemoradiation remains the current criterion standard treatment for high-grade gliomas. Regardless of aggressive treatment, tumor recurrence and radiation necrosis are 2 different outcomes. Differentiation of tumor recurrence from radiation necrosis remains a critical problem in these patients because of considerable overlap in clinical and imaging presentations. Contrast-enhanced MR imaging is the universal imaging technique for diagnosis, treatment evaluation, and detection of recurrence of high-grade gliomas. PWI and PET with novel radiotracers have an evolving role for monitoring treatment response in high-grade gliomas. In the literature, there is no clear consensus on the superiority of either technique or their complementary information. This review aims to elucidate the diagnostic performance of individual and combined use of functional (PWI) and metabolic (PET) imaging modalities to distinguish recurrence from posttreatment changes in gliomas.

Repeat Head CT for Neurologically Stable Patients With Mild Traumatic Subarachnoid Hemorrhage During Interfacility Transfer and Follow-Up Does Not Alter Patient Care [Formula: see text]

PURPOSE

To evaluate the impact of repeat head computed tomography (CT) during (1) interfacility transfer and (2) inpatient and/or outpatient follow-up on management, cost-effectiveness, and radiation dose in neurologically stable patients with mild traumatic subarachnoid hemorrhage (tSAH).

MATERIAL AND METHODS

This is a single-center retrospective study evaluating patients with mild tSAH presenting between January 2017 and July 2019. A total of 101 and 140 patients met the eligibility criteria for the first and second subgroups, respectively. Common inclusion criteria were isolated mild tSAH, Glasgow Coma Scale between 13 and 15, and neurological stability. Additional inclusion criteria for the first subgroup were availability of brain imaging at the outside institution prior to transfer and the second subgroup was the availability of follow-up imaging.

RESULTS

In the first subgroup, 76.20% of patients had stable SAH, 18.80% had reduced SAH, while 5% had an interval increase in SAH. None required any surgical intervention. Additional per-patient mean radiation exposure was 1.77 ± 0.26 mSv. In the second subgroup, all 140 patients had complete resolution of tSAH. One patient had a new tiny subdural hemorrhage, which subsequently resolved on follow-up. The additional mean radiation exposure was 2.47 ± 1.29 mSv. A total of 256 avoidable CT scans were performed resulting in excess health care costs of about US$531 696.

CONCLUSION

In neurologically stable isolated tSAH patients, repeat brain imaging during interfacility transfer and inpatient and/or outpatient follow-up do not alter patient management despite increased health care costs and radiation burden.

Retrospective, dual-centre review of imaging findings in neurosarcoidosis at presentation: prevalence and imaging sub-types

AIM

To assess the prevalence of various imaging manifestations in neurosarcoidosis (NS) patients at presentation and to explore if specific imaging findings may cluster in different sub-groups.

MATERIALS AND METHODS

A retrospective, dual-institution, systematic imaging review was undertaken of the magnetic resonance imaging (MRI) findings in 100 consecutive NS patients who presented over a 15-year period. Clustering analysis (k-mode) was performed to evaluate co-occurrence of imaging findings.

RESULTS

Non-enhancing white matter (NEWM) lesions were the most common imaging abnormality (56%), followed by leptomeningeal (47%) and pachymeningeal (32%) involvement. Other common manifestations included cranial nerve involvement (30%), parenchymal granulomas (27%), hypothalamic-pituitary-adrenal axis involvement (26%), and hydrocephalus (14%). Additionally, a higher prevalence of perivascular enhancement (23%), cerebrovascular events (including ischaemic and haemorrhagic events; 17%), and ependymal involvement (20%) were noted than recognised previously. Additional k-mode analysis was performed to explore underlying disease sub-clusters. This was evaluated for clusters varying between two though five (k=2-5). For k=4, the analysis revealed that the imaging findings may possibly be divided into disease sub-sets of four groups, each with varying distribution of imaging manifestations and clinical manifestations.

CONCLUSION

Overall, NEWM lesions and meningeal involvement are the most common imaging manifestations of NS. The prevalence of perivascular enhancement, cerebrovascular events, and ependymal involvement is likely higher than reported previously. Additionally, different imaging findings in NS may cluster together and imaging subtypes in NS possibly exist.

Expression of MTNR1A, steroid (ERα, ERβ, and PR) receptor gene transcripts, and the concentration of melatonin and steroid hormones in the ovarian follicles of buffalo

High ambient temperature exhibits a retrograde effect on buffalo reproduction because of heat stress. Moreover, melatonin is known to regulate reproductive changes in seasonally reproductive animals by binding to high affinity, G protein-coupled receptors. The MTNR1A gene is a prime receptor, mediating the effect of melatonin at the neuroendocrine level to control seasonal reproduction. In sheep, the role of melatonin is well known; however, studies have not been conducted in buffalo to determine its effect during favorable and unfavorable breeding seasons. Therefore, the present study aimed to (1) determine the expression of MTNR1A, ERα, ERβ, and PR gene transcripts in the ovarian follicles of buffalo during the summer and winter seasons and (2) analyze melatonin, 17β-estradiol, and progesterone concentrations in the follicular fluid of buffalo during both seasons. Murrah buffalo ovaries were collected during both the summer (May-June) and winter (December-January) seasons. All visible ovarian follicles were allocated into one of three groups: (1) small (8-9.9 mm); (2) medium (10-11.9 mm); and (3) large (12-14 mm). Follicular fluid was aspirated from each group of follicles for hormone analyses. The granulosa cells were processed for RNA extraction. Furthermore, they were subjected to real-time quantitative PCR to analyze the expression (relative quantification) of MTNR1A, ERα, ERβ, and PR in each follicular group. The expression of MTNR1A gene transcript decreased with the increasing size of the follicle and intrafollicular melatonin concentration. Expression of ERα and PR remained unaffected by the season and was similar (P > 0.05) in all groups. Expression of ERβ was higher (P < 0.05) in summer than winter; nevertheless, small-sized follicles from the summer exhibited higher (P < 0.05) expressions than medium- and large-sized follicles. The overall intrafollicular melatonin concentration was positively correlated (P < 0.05) with 17β-estradiol and progesterone concentrations. In conclusion, the decreased expression of MTNR1A and increased concentration of intrafollicular melatonin with the increasing size of the follicle indicates a probable role in folliculogenesis and ovulation in buffalo.

Cerebral computed tomographic angiography using third-generation reconstruction algorithm provides improved image quality with lower contrast and radiation dose

PURPOSE

We hypothesized that cerebral CT angiogram performed using third-generation reconstruction algorithm and lower contrast dose-low-kVp technique (LD-CTA) will provide better image quality when compared with regular contrast dose CTA at 120 kVp using a sinogram-affirmed iterative reconstruction algorithm (ND-CTA).

METHODS

Retrospective imaging review of 100 consecutive patients (50 each in LD- and ND-CTA groups). Two readers independently assessed the subjective image quality across multiple vascular segments on a Likert-like scale. Differences in contrast dose, CT dose index (CTDI), and dose length product (DLP) were compared using Mann-Whitney U test. Fisher's exact test was used to compare subjective image quality. Similarly, contrast- and signal-to-noise ratios (CNR and SNR) were compared in the mid-M1 MCA vessels bilaterally and the mid-basilar artery using Mann-Whitney U test. Interclass correlation coefficient (ICC) was calculated for the SNR/CNR values.

RESULTS

Both observers showed excellent correlation in subjective image quality (mean percentage agreement of 95.2% for group 1 versus 89.2% for group 2). LD-CTA group showed better SNR and CNR (p < 0.0001) for both MCA vessels and the mid-basilar artery. Interclass correlation coefficient showed moderate correlation (0.51-0.63) between readers. LD-CTA group also used lower contrast (49 cc versus 97 cc in ND-CTA) and had lower radiation exposure (DLP/CTDI for both groups 268.3/80.7 vs 519.5/36.08, both < 0.0001).

CONCLUSION

Next-generation reconstruction algorithm and low-kV scanning significantly improved image quality on cerebral CTA images despite lower contrast dose and, in addition, have lower radiation exposure.

Cerebrovascular complications in tuberculous meningitis-A magnetic resonance imaging study in 90 patients from a tertiary care hospital

BACKGROUND

Cerebrovascular complications of tuberculous meningitis (TBM) are associated with increased morbidity and mortality. We retrospectively reviewed clinicoradiological findings of 90 TBM patients who presented to a tertiary care hospital, with emphasis on frequency and distribution of infarcts on diffusion imaging and pattern of vascular involvement on magnetic resonance (MR) angiography (MRA).

MATERIALS AND METHODS

MR images of 90 TBM patients at presentation (2012-2018) were coanalyzed by two radiologists for tuberculomas, leptomeningeal enhancement (LM), hydrocephalus, infarct and vascular abnormalities. Infarcts were categorized based on location ("tubercular" (TB) or "ischemic" zones) and arterial supply (perforators and cortical branches). Clinical and laboratory findings were correlated with imaging data.

RESULTS

Ninety TBM patients (age 10-82 years) were enlisted after application of inclusion criteria. Tuberculomas were most common (100%) followed by LM (84.4%), cerebral infarcts (57.7%) and hydrocephalus (29%). Location-wise, 35% infarcts were in ischemic, 13% in TB and 15% in both zones. According to arterial supply, infarcts equally (50%) involved perforators from the lateral lenticulostriate and posterior cerebral (PCA)/basilar artery (BA) followed by medial lenticulostriate arteries (23%). MRA was available in 74.4% and abnormal in 43.2%. The middle cerebral artery was frequently involved (76%) followed by the anterior cerebral artery (38%), internal carotid artery (31%), PCA and BA. Six had diffuse narrowing with a paucity of distal vessels. Cerebral infarction was associated with hydrocephalus (p = .0019) and vasculitis (p < .001).

CONCLUSION

In TBM, strokes are common and mainly involve the perforators and cortical branches. MR is the imaging modality of choice for early diagnosis and timely management.

Abstract WP72: Low kV Computed Tomography Cerebral Angiogram Using Third-Generation Reconstruction Algorithm Provides Significantly Improved Image Quality With Lower Contrast and Radiation Exposure

Introduction/Aim: We aimed to determine if CTA imaging using third generation reconstruction algorithm and lower contrast dose-low kVp technique (LD-CTA) was comparable to regular contrast dose CTA at 120 kVp using a sinogram affirmed iterative reconstruction algorithm (ND-CTA).

Methods: Retrospective imaging review of 100 consecutive patients (50 each in LD- and ND-CTA groups). Two readers independently assessed the subjective image quality across multiple vascular segments on a Likert-like scale. Contrast- and signal-to-noise ratios (CNR/ SNR) were compared for the mid-M1-MCA vessels bilaterally and the mid-basilar artery. Fisher’s exact test was used to compare subjective image quality. Interclass correlation coefficient (ICC) was calculated for the SNR/CNR values. Finally differences in contrast dose, CT-dose index (CTDI) and dose length product (DLP) were compared using Mann-Whitney U test.

Results: Both observers showed excellent correlation in subjective image quality (mean percentage agreement of 95.2% (84-100%) for group-1 versus 89.2% (82%-98%) for group-2). The subjective scores were not statistically different in the anterior circulation but showed significantly better image quality for the basilar artery. LD-CTA group showed significantly better SNR and CNR (p < 0.0001) for both MCA vessels and the basilar artery. ICC showed moderate correlation (0.51-0.63) between the observers. Student paired t-test did not show any significant difference between the observers. LD-CTA group also used lower contrast (49 cc versus 103 cc in ND-CTA) and had lower radiation exposure (DLP/ CTDI for both groups 268.3/12.42 vs 519.5/ 25.15, both < 0.0001).

Conclusion: Next-generation reconstruction algorithm and low-Kv scanning significantly improved image quality on cerebral CTA images despite lower contrast dose, and in addition, have lower radiation exposure.

Survival after reoperation for recurrent glioblastoma

Determining which patients will benefit from reoperation for recurrent glioblastoma remains difficult and the impact of the volume of FLAIR signal hyperintensity is not well known. The primary purpose of this study is to analyze the impact of preoperative volume of FLAIR hyperintensity on prognosis. 37 patients who underwent a reoperation for recurrent glioblastoma after initial gross total resection followed by standard chemoradiation were retrospectively reviewed. Volumetric analysis of preoperative MR images from the initial and second surgery was performed and correlated with clinical data. Survival probabilities were estimated using the Kaplan-Meier method and Cox regression to assess the effect of risk factors on time to reoperation (TTR), progression-free survival (PFS) after reoperation, and overall survival (OS). The volumes of FLAIR signal hyperintensity prior to the initial surgery and reoperation were not associated with prognosis. TTR and OS were significantly affected by the preoperative enhancement volume at the initial surgery, with increasing volumes yielding poorer prognosis. Patients with tumor in critical/eloquent areas were found to have a worse prognosis. Median TTR was 11 months, median PFS after reoperation was 3 months, and OS in patients undergoing a reoperation was 21 months. The results suggest FLAIR signal change seen in patients with glioblastoma does not influence time to reoperation, progression-free survival, or overall survival. These findings suggest the amount of FLAIR signal change should not greatly influence a surgeon's decision to perform a second surgical resection compare to other factors, and when appropriate, aggressive surgical intervention should be considered.

Right ventricular dysfunction in rheumatic heart valve disease: A clinicopathological evaluation

Background

. Dysfunction of the right ventricle (RV) in rheumatic heart disease (RHD) is a poor prognostic factor. We planned to observe the clinicopathological changes in the RV of patients with RHD.

Methods

. We defined RV dysfunction by a myocardial performance index value of >0.4 on transthoracic echo-cardiography and included patients with isolated severe mitral stenosis in sinus rhythm with normal left ventricular (LV) function from April 2014 to April 2016. The patients were divided into two groups based on the absence (group I, n=21) and presence (group II, n=22) of RV dysfunction. RV muscle biopsy was evaluated for the presence of apoptosis, fibrosis and fat deposition apart from other clinical and echocardiography parameters.

Results

. Patients in both the groups had a similar demographic profile and LV dimensions and function. The age of the patients in the two groups was the only clinical parameter that was significantly different; older patients were in group II. A higher value for RV systolic pressure (RVSP) and the grade of tricuspid regurgitation was seen in group II. Though there was no significant difference in the presence of fibrosis and intensity of apoptosis in the RV biopsy samples, the deposition of fat in the interstitial spaces was decreased in group II. Age at presentation had no significant difference or correlation with the deposition of fibrosis or fat in the RV myocardial biopsy.

Conclusions

. Patients with RV dysfunction were older in age and their RVSP was raised at operation, suggesting that earlier intervention may help in preserving RV function.

Case of anomalous origin of right coronary artery from pulmonary artery associated with interrupted aortic arch type A, diagnosed by multidetector computed tomography angiography

Anomalous origin of the right coronary artery from pulmonary artery (ARCAPA) is a rare congenital anomaly of the coronary circulation, which can be easily missed by echocardiography. Interrupted aortic arch (IAA) is another rare congenital cardiac abnormality that typically presents in the first few weeks of life. We present a case of ARCAPA associated with IAA diagnosed with the help of multidetector computed tomography angiography, in a 7-year-old boy.

Perfusion MR imaging of enhancing brain tumors: Comparison of arterial spin labeling technique with dynamic susceptibility contrast technique

OBJECTIVE

Arterial spin labeling (ASL) magnetic resonance (MR) perfusion is a noninvasive and repeatable method for quantitatively measuring cerebral blood flow (CBF). This study aims to compare measurements of ASL-derived CBF with dynamic susceptibility contrast (DSC) MRI in the assessment of enhancing brain tumors (primary and metastatic), with an aim to use ASL as an alternative to DSC.

MATERIALS AND METHODS

Thirty patients with newly diagnosed brain tumors (16 meningiomas, 6 gliomas, 3 metastases, 2 cerebellopontine angle schwannoma, 1 central neurocytoma, and 2 low-grade gliomas) were examined using a 3T MR scanner. Values of CBF, regional cerebral blood flow (rCBF), and regional cerebral blood volume (rCBV) were determined in the tumor (T) as well as in the contralateral normal gray matter (GM) and white matter (WM). Tumor-to-GM or WM CBF, rCBF, and rCBV ratios were calculated to estimate normalized perfusion values (i.e., ASL normalized tumor blood flow [nTBF], DSC nTBF, and DSC normalized tumor blood volume [nTBV]) from the ASL and DSC techniques. ASL and DSC MRI derived perfusion parameters were compared using paired t-test and correlated using Pearson correlation coefficient.

RESULTS

Mean values for ASL nTBF and DSC nTBF using contralateral GM as the reference point were 2.98 ± 1.67and 2.91 ± 1.43, respectively. A very strong correlation coefficient was found between ASL nTBF and DSC nTBF with contralateral GM as the reference region (r = 0.903; R2= 0.813). Mean DSC nTBF and DSC nTBV also showed strong correlation (r = 0.83; R2= 0.701).

CONCLUSION

Our study results suggested that measurement of CBF from ASL possesses the potential for a noninvasive assessment of blood flow in intracranial tumors as an alternate to DSC MRI, in those patients requiring multiple follow-up imaging and in patients with impaired renal functions.

Texture Analysis in Cerebral Gliomas: A Review of the Literature

Texture analysis is a continuously evolving, noninvasive radiomics technique to quantify macroscopic tissue heterogeneity indirectly linked to microscopic tissue heterogeneity beyond human visual perception. In recent years, systemic oncologic applications of texture analysis have been increasingly explored. Here we discuss the basic concepts and methodologies of texture analysis, along with a review of various MR imaging texture analysis applications in glioma imaging. We also discuss MR imaging texture analysis limitations and the technical challenges that impede its widespread clinical implementation. With continued advancement in computational processing, MR imaging texture analysis could potentially develop into a valuable clinical tool in routine oncologic imaging.

Not Every Fat-Containing Lesion on Mammogram is a Benign Finding: Case Report and Review of Breast Malignant Phyllodes Tumor with Heterologous Liposarcomatous Differentiation

Phyllodes tumors (PTs) are a rare fibroepithelial tumor of the breast. Histopathological confirmation of stromal and epithelial component is required for making the diagnosis of PT, and stromal component carries an increased risk of sarcomatous transformation. We present imaging findings of a histologically proven case of malignant PT with heterologous liposarcomatous transformation of the breast.

Hand function outcome in closed small bone fractures treated by open reduction and internal fixation by mini plate or closed crossed pinning: a randomized controlled trail

PURPOSE

No study in literature clearly gives advantage of one method of surgical fixation of fracture over the other in metacarpal and phalangeal bones of hand comparing wider outcome measures.

MATERIALS AND METHODS

A randomized controlled trial between closed reduction and percutaneous Kirschner wire fixation or open reduction and internal fixation with mini fragment plates was conducted. A total of 32 patients with 16 in each group were taken in tertiary-level teaching hospital from 2014 to 2016. Four patients lost to follow-up apart from 32 studied. Inclusion criteria were age group 16-60 years, fresh (3 days) closed shaft fractures of metacarpal and phalanges. Outcome evaluated were time to union of fracture, degree of strength achieved measured with dynamometer, DASH scoring, range of motion of hand and each digit.

RESULTS

Both groups were comparable in terms of return to full hand function, union and total range of motion. K wire fixation results were slightly better than plating group in terms of early DASH score and grip strength after fixation.

CONCLUSION

No modality was found to be superior for fixation of small bone fractures of hand. But K wire being cheaper and without inherent complication of plating like scar and tendon irritation, K wire fixation is preferred over plating in shaft fractures of metacarpal and phalanges.

LEVEL OF EVIDENCE

Level I Therapeutic study.

In vitro accuracy and inter-observer reliability of CT angiography in detecting intracranial aneurysm enlargement

BACKGROUND AND PURPOSE

To evaluate the accuracy and inter-observer variability when CT angiography is used to identify unruptured intracranial aneurysm growth.

METHODS

Two silicone phantom models were used in this study. Each phantom had eight aneurysms of variable size. The size and location of aneurysms in phantom 1 were representative of real patient aneurysms who presented to our institution. Phantom 2 contained aneurysms in the same locations, but with enlargement in various directions. Three blinded board-certified neuroradiologists were asked to identify the size of each aneurysm in three dimensions using CT angiography. The individual enlargement detection rates and inter-observer agreement rates of aneurysm enlargement among the three experts were calculated.

RESULTS

The detection rate of aneurysm enlargement in one dimension was 58.3% among the three observers. Accurate detection of enlargement in all dimensions was 12.5% among the three observers. Detection accuracy was not related to the size of enlargement. Significant inter-observer measurement variability was present.

CONCLUSION

The use of CT angiography was associated with a poor ability to identify aneurysm enlargementaccurately. Further human studies are required to confirm our findings.

Magnetic resonance texture analysis utility in differentiating intraparenchymal neurosarcoidosis from primary central nervous system lymphoma: a preliminary analysis

PURPOSE

Neurosarcoidosis and primary central nervous system lymphomas, although distinct disease entities, can both have overlapping neuroimaging findings. The purpose of our preliminary study was to assess if magnetic resonance texture analysis can differentiate parenchymal mass-like neurosarcoidosis granulomas from primary central nervous system lymphomas.

METHODS

A total of nine patients was evaluated, four with parenchymal neurosarcoidosis granulomas and five with primary central nervous system lymphomas. Magnetic resonance texture analysis was performed with commercial software using a filtration histogram technique. Texture features of different sizes and variations in signal intensity were extracted at six different spatial scale filters, followed by feature quantification using statistical and histogram parameters and 36 features were analysed for each sequence (T1-weighted, T2-weighted, fluid-attenuated inversion recovery, diffusion-weighted, apparent diffusion coefficient, T1-post contrast). The non-parametric Mann-Whitney test was used to evaluate the differences between different texture parameters.

RESULTS

The differences in distribution of entropy on T2-weighted imaging, apparent diffusion coefficient and T1-weighted post-contrast images were statistically significant on all spatial scale filters. Magnetic resonance texture analysis using medium and coarse spatial scale filters was especially useful in discriminating neurosarcoidosis from primary central nervous system lymphomas for mean, mean positive pixels, kurtosis, and skewness on diffusion-weighted imaging ( P < 0.004-0.030). At spatial scale filter 5, entropy on T2-weighted imaging ( P = 0.001) was the most useful discriminator with a cut-off value of 6.12 ( P = 0.001, area under the curve (AUC)-1, sensitivity (Sn)-100%, specificity (Sp)-100%), followed by kurtosis and skewness on diffusion-weighted imaging with a cut-off value of -0.565 ( P = 0.011, AUC-0.97, Sn-100%, Sp-83%) and-0.365 ( P = 0.008, AUC-0.98, Sn-100%, Sp-100%) respectively.

CONCLUSION

Filtration histogram-based magnetic resonance texture analysis appears to be a promising modality to distinguish parenchymal neurosarcoidosis granulomas from primary central nervous system lymphomas.

Genotype of MTNR1A gene regulates the conception rate following melatonin treatment in water buffalo

Buffaloes have tendency to show seasonal reproduction and remain in anestrus due to limited ovarian activity during summer. The seasonal reproductive behavior is ascribed the effect of melatonin related to photoperiod. Treating animals with melatonin could be a possible strategy to overcome the problem. The role of MTNR1A gene has not been fully explained in the buffalo. Therefore, we conducted a study on 114 buffalo heifers to detect the polymorphic site in MTNR1A gene and further treated them with melatonin implants to investigate the role of most frequent genotype following melatonin treatment on pregnancy. The present investigation is the first to investigate the association between melatonin treated different MTNR1A genotype buffalo and pregnancy. We confirmed SNP at position 72 in 812 bp fragment exon II of MTNR1A gene. RFLP of PCR products with Hpa I enzyme resulted in three genotypes: TT (812bp), CT (812, 743, 69bp) and CC (743, 69bp). Next, buffaloes of each genotype (TT, CC, CT; n = 28 for each) were treated with melatonin implants to compare the conception rate with their corresponding untreated control (n = 10 for each genotype). Melatonin concentrations were higher (P < 0.05) for the treatment groups of all genotypes compared to their respective untreated control from day 1-28. The pregnancy rate was significantly associated with the MTNR1A genotype. The conception rate was higher (P < 0.05) for TT genotype than for the other genotypes of buffaloes treated with melatonin. Furthermore, buffaloes of TT genotype treated with melatonin started exhibiting estrus activity soon from second week of melatonin treatment (14.1 ± 2.1; range: 10-17 days) and were found to be 7.8 times more likely to become pregnant compared to other genotypes following melatonin treatment. In conclusion, TT genotype of MTNR1A gene is more sensitive to melatonin treatment that favours pregnancy in buffaloes during summer.