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.

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.

Radiomic Based Machine Learning Performance for a Three Class Problem in Neuro-Oncology: Time to Test the Waters?

Prior radiomics studies have focused on two-class brain tumor classification, which limits generalizability. The performance of radiomics in differentiating the three most common malignant brain tumors (glioblastoma (GBM), primary central nervous system lymphoma (PCNSL), and metastatic disease) is assessed; factors affecting the model performance and usefulness of a single sequence versus multiparametric MRI (MP-MRI) remain largely unaddressed. This retrospective study included 253 patients (120 metastatic (lung and brain), 40 PCNSL, and 93 GBM). Radiomic features were extracted for whole a tumor mask (enhancing plus necrotic) and an edema mask (first pipeline), as well as for separate enhancing and necrotic and edema masks (second pipeline). Model performance was evaluated using MP-MRI, individual sequences, and the T1 contrast enhanced (T1-CE) sequence without the edema mask across 45 model/feature selection combinations. The second pipeline showed significantly high performance across all combinations (Brier score: 0.311-0.325). GBRM fit using the full feature set from the T1-CE sequence was the best model. The majority of the top models were built using a full feature set and inbuilt feature selection. No significant difference was seen between the top-performing models for MP-MRI (AUC 0.910) and T1-CE sequence with (AUC 0.908) and without edema masks (AUC 0.894). T1-CE is the single best sequence with comparable performance to that of multiparametric MRI (MP-MRI). Model performance varies based on tumor subregion and the combination of model/feature selection methods.

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.

"Multimodality imaging of the extrapleural space lesions".

Extrapleural space (EPS) is a potential space between the outer layer of the parietal pleura and the inner layer of the chest wall and the diaphragm. Many different pathologies including chronic inflammatory conditions, infections, trauma, neoplastic disease (both benign and malignant) as well as many infiltrative disorders can involve the EPS. It is one of the frequently overlooked entity on imaging due to relative lack of understanding of the anatomy and the imaging appearances of the diseases localized to this space. The knowledge of the EPS is essential for the radiologists as the pathologies which involve the EPS may require different treatment approach compared to pleural or parenchymal lung disease. Additionally, the EPS involvement may influence the staging and treatment planning for chest malignancies. In this review, we give an overview of the anatomy and various pathologies involving EPS, utility of different imaging modalities in the evaluation of EPS lesions with emphasis on cross sectional imaging and emerging technologies like spectral CT and its role in recognizing the imaging features which enable specific diagnosis of various pathologies.

Asymptomatic COVID-19 Infection Detected on 18F-FDG PET/CT Scan Done for Multiple Myeloma.

A 69-year-old woman with multiple myeloma came to our department for F-FDG PET/CT scan for routine surveillance. The patient denied any history of fever, cough, shortness of breath, or body aches. F-FDG PET/CT scan from vertex to knees was performed. PET/CT images revealed extensive peripheral ground-glass opacities showing intense FDG uptake (SUVmax 12) involving bilateral lower lobes. Possibility of an infective etiology including novel coronavirus (COVID-19) infection was raised. The patient's oropharyngeal swab for COVID-19 by polymerase chain reaction amplification test came back positive for COVID-19 infection. The patient and her husband were advised home quarantine for 14 days.

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.

18F-Fluciclovine-Avid Mediastinal Lymph Node Metastasis of Cutaneous Malignant Melanoma.

ABSTRACT: A 63-year-old man with recent diagnosis of high-risk prostate adenocarcinoma was referred to our Nuclear Medicine Department for 18F-fluciclovine PET/CT to rule out metastasis in the setting of elevated serum prostate-specific antigen levels. The patient had previous history of nodular melanoma of the right cheek treated 6 years back with surgery and adjuvant radiation. Surveillance 18F-FDG PET/CT for melanoma 1 month back had revealed enlarged FDG-avid mediastinal para-aortic lymph nodes, which on endoscopic biopsy had revealed melanoma metastasis. On current fluciclovine PET/CT, the same enlarged para-aortic lymph nodes showed fluciclovine uptake, suggesting false-positive uptake.

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.

Potential False-Positive Meckel's Scan Caused by Umbilical Ornamentation.

An 18-year-old woman presented to the emergency department for bloody stools. A CT scan of the abdomen ruled out intussusception. Meckel's scan was ordered to rule for Meckel's diverticulum before upper endoscopy and colonoscopy. After proper pretreatment with H2 blocker, Tc-pertechnetate Meckel's scan was performed. Dynamic planar imaging revealed a focus of gradual increase in uptake in midabdomen suggestive of Meckel's diverticulum. A SPECT/CT was done to localize the focus of uptake. Surprisingly, the focus of uptake localized to the periumbilical region on SPECT/CT images. The cause of uptake could be due to local inflammation from umbilical ornamentation.

Association of gallbladder hyperkinesia with acalculous chronic cholecystitis: A case-control study.

BACKGROUND: This is the first case-control study investigating an association between gallbladder hyperkinesia and symptomatic acalculous chronic cholecystitis. METHODS: This retrospective study in a single academic center compared resolution of biliary pain in adults with gallbladder hyperkinesia, defined as a hepatobiliary iminodiacetic acid scan ejection fraction ≥80%, undergoing cholecystectomy (study group) with those treated medically without cholecystectomy (control group). Of 1,477 hepatobiliary iminodiacetic acid scans done between 2013 and 2018, a total of 296 adults without gallstones had an ejection fraction ≥80%, of whom 46 patients met predetermined eligibility criteria. Demographic data, hepatobiliary iminodiacetic acid scan ejection fraction, chronicity of pain, and resolution of pain were compared between groups. RESULTS: Demographics (mean ± standard deviation) in the control group (n = 25) and in the study group (n = 21) were, respectively, age 40 y ± 16 y and 39 y ± 14 y, body mass index 28.9 ± 5.2 and 29.1 ± 7.1 kg/m2, with 15 (60%) and 18 (86%) females in each. Resolution of pain after cholecystectomy occurred in 18 of 21 patients (86%); however, pain persisted in 20 of 25 patients (80%) treated medically after mean follow-up of 36 ± 28 months (range 10-120 months) (P < .01). Pain resolution with cholecystectomy was independent of demographic variables, hepatobiliary iminodiacetic acid scan ejection fraction, and chronicity of pain. The odds of pain resolution was 19.7 times greater with cholecystectomy than without (odds ratio, 19.7; 95% confidence interval, 4.34, 89.43; P < .01), and remained robust even with the odds adjusted for each covariate. Gallbladder histopathology confirmed chronic cholecystitis in all 21 cholecystectomy specimens. CONCLUSION: Symptomatic gallbladder hyperkinesia could be a new indication for cholecystectomy in adults.

Emergency Imaging in Pregnancy and Lactation [Formula: see text].

The use of diagnostic imaging studies in the emergency setting has increased dramatically over the past couple of decades. The emergency imaging of pregnant and lactating patients poses unique challenges and calls upon the crucial role of radiologists as consultants to the referring physician to guide appropriate use of imaging tests, minimize risk, ensure timely management, and occasionally alleviate unwarranted trepidation. A clear understanding of the risks and benefits involved with various imaging tests in this patient population is vital to achieve this. This review discusses the different safety and appropriateness issues that could arise with the use of ionizing radiation, iodinated-, and gadolinium-based contrast media and radiopharmaceuticals in pregnant and lactating patients. Special considerations such as trauma imaging, safety concerns with magnetic resonance imaging and ultrasound, management of claustrophobia, contrast extravasation, and allergic reactions are also reviewed. The consent process for these examinations has also been described.

Fishing in muddy waters- co-existing dual intracranial pathology in PRES: A case series and review of literature.

Posterior reversible encephalopathy syndrome (PRES) is a neurotoxic state often characterized by altered mental state and is seen in various clinical settings. Although it is often reversible, it may result in long term sequelae. The typical and atypical neuroimaging findings seen in PRES have been previously well-described in the literature. However, the presence of other co-existing intracranial lesions along with PRES can occasionally confound the imaging findings and poses a diagnostic challenge. Herein, the authors report four cases of PRES with etiologically different co-existing intracranial lesions confounding the clinical and imaging manifestations. When presented with atypical imaging findings in PRES, the possibility of a co-existing intracranial pathology with superimposed imaging findings should be considered.

Giant vertebral hemangioma masquerading as aggressive tumor: Tc-99m tagged RBC scan can help to solve the diagnostic conundrum!

Hemangiomas are the most common benign lesions involving the spine. Metastasis is the most common malignant condition. The diagnosis of typical hemangiomas on conventional CT and MRI imaging is straightforward. However, when the hemangiomas are very large they may have atypical features making their diagnosis on these conventional imaging modalities inconclusive. In such cases nuclear medicine techniques such as Tc-99m RBC may aid in resolving the diagnostic conundrum. Awareness and use of proper diagnostic modality can prevent unnecessary biopsy. In this case report we try to highlight the added value of Tc-99m RBC scan to conventional imaging techniques in differentiating giant vertebral hemangioma from more aggressive malignant tumors.

Imaging findings in spinal sarcoidosis: a report of 18 cases and review of the current literature.

PURPOSE: Spinal sarcoidosis, referring to involvement of the spine in sarcoidosis, is relatively rare and may mimic other neurological disease affecting the spine. The authors present a clinic radiological review of 18 spinal sarcoidosis patients who presented to a tertiary hospital, with emphasis on initial imaging and radiological response to treatment. MATERIALS AND METHODS: We retrospectively reviewed our departmental imaging archives over a 15-year period and found 49 cases of neurosarcoidosis out of which 18 patients had spinal magnetic resonance imaging. RESULTS: Approximately 72% (13/18) of the neurosarcoidosis patients showed some form of spinal involvement. The clinical, epidemiological and imaging data were reviewed for these 13 patients at presentation and follow-up. The findings on magnetic resonance imaging included leptomeningeal enhancement (61%), pachymeningeal (23%), intramedullary enhancing lesions (38%) and bony involvement (15%). The cervical segment was most frequently involved followed by the thoracic segment. Involvement was often long segment (4.2 spinal segments) with proclivity for the dorsal cord. Mean follow-up was 23.2 months. A complete or near-complete radiological response occurred in 66% while partial response was seen in 25% patients. Four patients had isolated central nervous system involvement including one with isolated spinal cord involvement. On diffusion-weighted imaging, the apparent diffusion coefficient of intramedullary lesions was increased compared to normal-appearing cord on baseline and subsequent follow-up scans. CONCLUSIONS: Spinal sarcoidosis was previously considered uncommon but is being increasingly recognized with widespread use of magnetic resonance imaging. Proclivity for dorsal surface involvement is characteristic, although not necessarily pathognomonic. Also, quantitative diffusion studies may serve as a biomarker for the disease activity and parenchymal injury.

An unusual location of juvenile angiofibroma: a case report and review of the literature.

A 10-year-old boy presented with left-sided nasal obstruction and epistaxis. Endoscopic evaluation revealed a polypoid mass in the vestibule arising from the lateral wall of the nasal cavity anteroinferior to the left inferior turbinate. Computed tomography (CT) scan showed a soft tissue opacity in the vestibule of the left nasal cavity. After the endoscopic excision of the mass, postoperative and histopathological analyses confirmed the diagnosis of an angiofibroma.