Differentiating Radiation Necrosis and Metastatic Progression in Brain Tumors Using Radiomics and Machine Learning.

OBJECTIVES: Distinguishing between radiation necrosis (RN) and metastatic progression is extremely challenging due to their similarity in conventional imaging. This is crucial from a therapeutic point of view as this determines the outcome of the treatment. This study aims to establish an automated technique to differentiate RN from brain metastasis progression using radiomics with machine learning. METHODS: Eighty-six patients with brain metastasis after they underwent stereotactic radiosurgery as primary treatment were selected. Discrete wavelets transform, Laplacian-of-Gaussian, Gradient, and Square were applied to magnetic resonance post-contrast T1-weighted images to extract radiomics features. After feature selection, dataset was randomly split into train/test (80%/20%) datasets. Random forest classification, logistic regression, and support vector classification were trained and subsequently validated using test set. The classification performance was measured by area under the curve (AUC) value of receiver operating characteristic curve, accuracy, sensitivity, and specificity. RESULTS: The best performance was achieved using random forest classification with a Gradient filter (AUC=0.910±0.047, accuracy 0.8±0.071, sensitivity=0.796±0.055, specificity=0.922±0.059). For, support vector classification the best result obtains using wavelet_HHH with a high AUC of 0.890±0.89, accuracy of 0.777±0.062, sensitivity=0.701±0.084, and specificity=0.85±0.112. Logistic regression using wavelet_HHH provides a poor result with AUC=0.882±0.051, accuracy of 0.753±0.08, sensitivity=0.717±0.208, and specificity=0.816±0.123. CONCLUSION: This type of machine-learning approach can help accurately distinguish RN from recurrence in magnetic resonance imaging, without the need for biopsy. This has the potential to improve the therapeutic outcome.

The relationship between iodinated contrast material temperature and adverse reactions: A meta-analysis of 307,329 injections.

OBJECTIVE: The effect of iodinated contrast material (CM) temperature on injection pressures and viscosity has been well established. However, the effect of extrinsic warming of CM on allergic reactions and extravasations remains unclear. The purpose of this study is to compare the rates of allergic reactions and extravasations between warmed CM to room temperature CM. METHODS: We conducted a comprehensive systematic search using PubMed, Embase, and Web of Science databases for all studies that assess the impact of warmed CM on adverse reactions. The primary outcomes of our study were allergic reaction and extravasation rates. We calculated weighted pooled odds ratios (OR) and 95% confidence intervals (CI) for all outcomes using the random-effects model. A P-value <0.05 was considered statistically significant. We conducted subgroup analyses based on the viscosity of the CM. RESULTS: A total of five studies, including 307,329 CM injections (86,676 at room temperature and 220,653 warmed to 37 °C), were included in the analysis. For high viscosity CM, pre-warming was associated with significantly lower allergic reaction rates (OR: 0.59, 95% CI: 0.49-0.72, P < 0.00001). There was no significant difference in rates of extravasation for high viscosity CM (OR: 0.53, 95% CI: 0.20-1.43, P = 0.21). DISCUSSION: Our meta-analysis suggests that warming CM to 37 °C is a safe and effective approach to reduce the risk of allergic reactions and physiologic reactions during injection of high-viscosity CM. However, there was no significant difference in extravasation rates between warmed and room temperature CM, regardless of viscosity.

Injectable Cell-Laden Nanofibrous Matrix for Treating Annulus Fibrosus Defects in Porcine Model: An Organ Culture Study.

Lower back pain commonly arises from intervertebral disc (IVD) failure, often caused by deteriorating annulus fibrosus (AF) and/or nucleus pulposus (NP) tissue. High socioeconomic cost, quality of life issues, and unsatisfactory surgical options motivate the rapid development of non-invasive, regenerative repair strategies for lower back pain. This study aims to evaluate the AF regenerative capacity of injectable matrix repair strategy in ex vivo porcine organ culturing using collagen type-I and polycaprolactone nanofibers (PNCOL) with encapsulated fibroblast cells. Upon 14 days organ culturing, the porcine IVDs were assessed using gross optical imaging, magnetic resonance imaging (MRI), histological analysis, and Reverse Transcriptase quantitative PCR (RT-qPCR) to determine the regenerative capabilities of the PNCOL matrix at the AF injury. PNCOL-treated AF defects demonstrated a full recovery with increased gene expressions of AF extracellular matrix markers, including Collagen-I, Aggrecan, Scleraxis, and Tenascin, along with anti-inflammatory markers such as CD206 and IL10. The PNCOL treatment effectively regenerates the AF tissue at the injury site contributing to decreased herniation risk and improved surgical outcomes, thus providing effective non-invasive strategies for treating IVD injuries.

Assessment of US Radiology Residency Program Websites in the COVID-19 Era.

OBJECTIVE: To provide an updated evaluation of radiology residency program websites in light of virtual interviewing during the COVID-19 pandemic and encourage programs to improve the quality of their online website presence. METHODS: We evaluated the websites of 197 US radiology residency programs between November and December 2021 for the presence or absence of 30 metrics. The metrics chosen are those considered important by applicants when choosing a program and have been used in other similar papers. RESULTS: Of the 197 programs, 192 (97.5%) had working websites. The average radiology residency website had 16 of 30 (54%) metrics listed on their websites. Five programs did not have accessible websites and were not included in the analysis. The most comprehensive website had 29 of 30 (97%) of metrics listed and the least comprehensive website had 2 of 30 (7%). There is a statistically significant difference in website comprehensiveness between top 20 and non-top 20 radiology program websites. CONCLUSION: Although radiology residency program websites have generally become more comprehensive over time, there is still room for improvement, especially in times of virtual interviews when residency applicants are becoming more and more reliant on program websites to gain essential information about a program. Some key areas to include are diversity and inclusion initiatives, resident wellness, applicant information, program benefits, and showcase of people in the program.

Proteus-Like Syndrome: A Rare Phenotype of Phosphatase and Tensin Homolog Hamartoma Tumor Syndrome.

The phosphatase and tensin homolog (PTEN) hamartoma tumor syndrome (PHTS) is a collection of diseases stemming from mutations in the PTEN tumor suppressor gene and is characterized by variable expressivity and abnormal overgrowth in multiple body systems. Its clinical manifestations include, but are not limited to, lipomas, limb overgrowth, dermatologic lesions, and malignancy. The infrequency of occurrence and broadness of clinical presentation has made the diagnosis and differentiation of different subtypes of PHTS challenging. This case report describes a five-year-old patient with a history of autism and macrocephaly who presented to the emergency department with right lower quadrant (RLQ) pain concerning for appendicitis. A physical exam was significant for right leg hemihypertrophy. Imaging ruled out appendicitis but diagnosed two large right-sided abdominal lipomas. The patient was discharged with the recommendation to pursue genetic testing given the physical exam findings and history. Following confirmation of a PTEN tumor suppressor gene mutation, the patient continued to have increased frequency of abdominal pain, developed vision changes, and was diagnosed with a benign follicular thyroid nodule. Hemihypertrophy, recurrent unilateral lipomas, and a confirmed PTEN mutation are consistent with a diagnosis of Proteus-like syndrome, a rare subtype of PHTS.

Acing the Fundamentals of Radiology: An Online Series for Medical Students and Interns.

PURPOSE: The current undergraduate radiology education predominantly integrates radiology with other disciplines during preclerkship years and is often taught by nonradiologists. Early exposure to radiology and profound understanding of scientific fundamentals of imaging modalities and techniques are essential for a better understanding and interest in the specialty. Furthermore, the COVID-19 pandemic-related impact on in-person medical education aggravated the need for alternative virtual teaching initiatives to provide essential knowledge to medical students. METHODS: The authors designed an online 7-session course on the principles of imaging modalities for medical students and fresh graduates in the United States and abroad. The course was delivered online and taught by radiologists from different US institutions. Pretests and posttests were delivered before and after each session, respectively, to assess change in knowledge. At the end of the course, a survey was distributed among students to collect their assessment and feedback. RESULTS: A total of 162 students and interns initially enrolled in the program by completing a sign-up interest form. An average of 65 participants attended each live session, with the highest attendance being 93 live attendees. An average of 44 attendees completed both the pretest and posttest for each session. There was a statistically significant increase in posttest scores compared with pretest scores ( P < 0.01) for each session; on average, the posttest scores were 48% higher than the pretest scores. A total of 84 participants answered the end-of-course survey. A total of 11% of the respondents described themselves as first year, 17% as second year, 18% as third year, 21% as fourth year, and 33% as "other." Attendees were enrolled in medical schools across 21 different countries with 35% of the respondents studying medicine in the United States. More than 76% of the respondents stated that they "strongly agree" that the program increased their understanding of radiology, increased their interest in radiology, and would be useful in their clinical practice in the future. Eighty-three percent of the respondents stated that they "strongly agree" that "this course was a worthwhile experience." Particularly, more than 84% of the respondents stated that among the most important components in enhancing their understanding of radiology were "the interpretation of normal imaging" and "interpretation of clinical cases." Ninety-two percent of the respondents stated that "the amount of effort to complete the requirements for this program was just right." Participants were also asked to rate each of the 8 sessions using the following scale: poor = 1 point, fair = 2, good = 3, and excellent = 4. The average rating for all 8 sessions was 3.61 points (SD = 0.55), which translates to 96% of the sessions being rated good or excellent. Eighty percent of the participants reported that the topics presented in the program were "excellent and clinically important to learn," and 20% of the participants reported that the topics presented were "good and somewhat important to learn." The participants were asked to evaluate their confidence regarding basic radiology skills before and after the program using the following scale: not confident at all = 1 point, somewhat confident = 2, moderately confident = 3, and very confident = 4. Figure 2 summarizes the responses of the participants. CONCLUSIONS: An online course to teach the fundamentals of imaging modalities could be delivered through a webinar format to medical students and interns in several countries to address the potential gaps in radiology education, therefore increasing their understanding of the different imaging modalities and their proper use in medicine.

Electrical Stimulation-Mediated Tissue Healing in Porcine Intervertebral Disc Under Mechanically Dynamic Organ Culture Conditions.

STUDY DESIGN: Porcine intervertebral discs (IVDs) were excised and then drilled to simulate degeneration before being electrically stimulated for 21 days while undergoing mechanical loading. The discs were then analyzed for gene expression and morphology to assess regeneration. OBJECTIVE: The purpose of this study was to investigate the effectiveness of the electrical stimulation of IVD treatment as an early intervention method in halting the progression of degenerative disc disease using an ex-vivo porcine model. SUMMARY OF BACKGROUND DATA: Treatments for degenerative disc disease are limited in their efficacy and tend to treat the symptoms of the disease rather than repairing the degenerated disc itself. There is a dire need for an early intervention treatment that not only halts the progression of the disease but contributes to reviving the degenerated disc. METHODS: Lumbar IVDs were extracted from a mature pig within 1 hour of death and were drilled with a 1.5 mm bit to simulate degenerative disc disease. Four IVDs at a time were then cultured in a dynamic bioreactor system under mechanical loading for 21 days, two with and two without the electrical stimulation treatment. The IVDs were assessed using histological analysis, magnetic resonance imaging, and quantitative reverse transcriptase polymerase chain reaction to quantify the effectiveness of the treatment on the degenerated discs. RESULTS: IVDs with electrical stimulation treatment exhibited extensive annular regeneration and prevented herniation of the nucleus pulposus (NP). In contrast, the untreated group of IVDs were unable to maintain tissue integrity and exhibited NP herniation through multiple layers of the annulus fibrosus. Gene expression showed an increase of extracellular matrix markers and antiinflammatory cytokine interleukin-4 (IL-4), while decreasing in pro-inflammatory markers and pain markers in electrically stimulated IVDs when compared to the untreated group. CONCLUSION: The direct electrical stimulation application in NP of damaged IVDs can be a viable option to regenerate damaged NP and annulus fibrosus tissues.

Diagnosing cystic duct patency during myocardial perfusion imaging (MPI), using Tc99m Sestamibi (MIBI), as an adjunct benefit in the acute setting.

OBJECTIVE: Tc99m methoxy isobutyl isonitrile (MIBI) has been used for myocardial perfusion imaging (MPI) for the detection of ischemia. This study aimed to investigate the feasibility of effectively evaluating cystic duct patency, during routine visual analysis of the raw MPI and/or with the three-dimensional reconstructed data. METHODS: A retrospective investigation of 91 patients undergoing cardiac MIBI scan for acute chest pain and hepatobiliary scintigraphy (HBS) was performed, within no more than 3 months for suspected gallbladder obstructive disease. Gallbladder visualization during either the stress or rest portion of the MIBI was indicative of cystic duct patency. These results were compared to those by the HBS studies. RESULTS: Ten patients had the MIBI and HBS 4 days apart, both analyses concurred 100% with the diagnosis of cystic duct patency. 16 patients had both examinations between 4 days and 3 weeks and had an agreement of 87.5% with cystic duct patency. 65 patients had both tests 3 weeks to 3 months apart and had an agreement of 84.6% with cystic duct patency. CONCLUSION: The initial results of this study indicate that MPI with Tc99m MIBI is useful in detecting a patent cystic duct, above all in the setting of acute gallbladder pathology. ADVANCES IN KNOWLEDGE: In this article, we introduce a novel method to diagnose cystic duct patency in the acute setting thus effectively ruling out acute cholecystitis, during MPI. Our method can potentially improve patient outcomes by reducing the volume of imaging needed to exclude a diagnosis of acute gallbladder pathology. This in turn, keeps in line with decreasing the cost for the patient, leading to a more sound value-based care.

Accidental Concentrated Hydrogen Peroxide Ingestion Associated with Portal Venous Gas.

A case of a 52-year old male patient who presented to the emergency department with severe nausea and vomiting following accidental ingestion of H2O2. A computed tomography (CT) abdomen performed at our institution demonstrated extensive portal venous gas throughout the liver with few gas droplets seen in the extrahepatic portal vein portion. Pneumatosis was also noted in the wall of the gastric antrum. Upper GI Endoscopy was done revealing diffuse hemorrhagic gastritis and mild duodenal bulb erosion. The patient was treated with hyperbaric oxygen. On the second day of admission, the patient was able to eat without difficulty or pain. Accidental ingestion of high concentration H2O2 solution has been shown to cause extensive injury to surrounding tissues. The injury occurs via three main mechanisms: corrosive damage, oxygen gas formation, and lipid peroxidation. We report a case of accidental ingestion of a highly concentrated (35%) solution of H2O2 causing portal venous gas.

Imaging of secretory tumors of the gastrointestinal tract.

Gastrointestinal secretory tumors, or gastroenteropancreatic neuroendocrine tumors, encompass a wide array of endocrine cell tumors. The significance of these tumors lies in their ability to alter physiology through hormone production as we well as in their malignant potential. Functioning tumors may present earlier due to symptomatology; conversely, non-functioning tumors are often diagnosed late as they reach large sizes, causing symptoms secondary to local mass effect. Imaging aids in the diagnosis, staging, and prognosis and provides key information for presurgical planning. Although most of these tumors are sporadic, some are associated with important syndromes and associations, knowledge of which is critical for patient management. In this article, we provide an overview of secretory and neuroendocrine tumors of the GI tract and pancreas.

Ipsilateral arcuate foramen and high-riding vertebral artery: implication on C1-C2 instrumentation.

BACKGROUND CONTEXT: Several methods for C1-C2 stabilization have been described in the literature. These include C1-C2 transarticular and C1 lateral mass screws. In patients with aberrant anatomy such as a high-riding vertebral artery (VA) or the presence of an arcuate foramen at C1, there exists a higher risk of VA injury. This may lead to excessive bleeding, stroke, and possibly death. There have been several studies determining the incidence of arcuate foramen and high-riding VA occurring individually in the general population, but none have determined their occurrence simultaneously. PURPOSE: To determine the prevalence of ponticulus posticus and high-riding VA occurring simultaneously in the general population. STUDY DESIGN: Radiological study. METHODS: One hundred consecutive computed tomography (CT) scans of the cervical spine were reviewed. Scans that contained an arcuate foramen were identified, and it was indicated whether the foramen was right sided, left sided, or bilateral. In the same group, the thickness of the isthmus and the internal height of the lateral mass of C2 were measured. The VA was considered high riding if the isthmus thickness was less than 5 mm or the isthmus internal height was less than 2 mm. RESULTS: Fourteen out of one hundred (14%) patients had a fully formed arcuate foramen. Of these, six were left sided, three were right sided, and five were bilateral. In addition, there were 24 (24%) patients with partially formed ponticulus posticus. Thirty-two (32%) patients were identified to have a high-riding VA. Of these, 13 were left sided, 9 were right sided, and 10 were bilateral. Five (5%) had an ipsilateral arcuate foramen and high-riding VA. CONCLUSIONS: The arcuate foramen and high-riding VA are common anomalies that are often not recognized. Although ipsilateral high-riding VA and arcuate foramen rarely occur in the general population, proper identification of these anomalies on preoperative CT scan facilitates planning the safest technique for C1-C2 instrumentation.

Retro-cardiac esophageal mobility and deflection to prevent thermal injury during atrial fibrillation ablation: an anatomic feasibility study.

BACKGROUND: Atrial fibrillation (AF) ablation often causes minor esophageal (ESO) injury, and sometimes lethal posterior left atria (PLA)-ESO fistula. Avoidance techniques (energy reduction and/or complete target avoidance) provide questionable ESO protective value, and are likely associated with increased AF recurrence. METHODS AND RESULTS: Potential independent mobility, deflectability and age-related anatomic factors, assessed by multi-position, and age-progressive thoracic computed tomography scans, show (1) mobility of the retro-cardiac ESO-PLA juxtaposition, (2) age-related increased thermal ablation vulnerability; and also, age-increased potential for retro-cardiac ESO mobility and deflectability to avoid collateral injury; and that (3) the retro-cardiac vertebral bodies and the descending aorta create a patient-specific esophageal corridor which defines the resting supine esophageal position and the subsequent PLA-ESO crossing points. CONCLUSION: A small, 1-3 mm, increase in separation of the ESO relative to the PLA occurs when moving the patient from supine to lateral and from supine to prone position. Because of the concave spine; the PLA-ESO area of apposition increases. Patient rotation of 90° and 180° does not create enough passive PLA-ESO separation to avoid collateral ESO thermal energy; but, active repositioning lateral and out of ESO corridor appears feasible.

Extrarenal malignant rhabdoid tumors: radiologic findings with histopathologic correlation.

Extrarenal malignant rhabdoid tumors (MRT) are extremely rare. There have been only a few cases of MRT described in the literature and even fewer in the radiology literature. We present rare uterine and hepatic MRT and their computed tomography, magnetic resonance, and ultrasound imaging features with histopathologic correlation. Although the final diagnosis is based largely on histopathology, radiologists should include MRT in their differential considerations, regardless of tumor location, when they are dealing with an extremely aggressive tumor of early childhood.

A rare case of extensive spinal epidural abscess in a diabetic patient.

STUDY DESIGN: Case report. OBJECTIVE: We report a rare case of extensive spinal epidural abscess in a patient with diabetes. SUMMARY OF BACKGROUND DATA: Spinal epidural abscess is a very uncommon infection that requires prompt recognition and proper management to avoid potentially disastrous complications. This lesion can expand to compress the spinal cord causing severe symptoms and complications. METHODS: Combination of the patient clinical history, physical examination, laboratory results, radiologic and intraoperative findings along with brief related literature review. RESULTS: We present a rare case of spinal epidural abscess extending to the entire length of the spinal cord in a previously undiagnosed patient with diabetes. CONCLUSION: Diabetes is an important condition that can predispose an individual to the development of localized or extensive spinal epidural abscess.

CT and MRI findings with histopathologic correlation of a unique bilateral orbital mantle cell lymphoma in Graves' disease: a case report and brief review of literature.

Bilateral orbital mantle cell lymphoma is rare. We present an unusual case report of a patient with Graves' disease and no previous history of lymphoma, who was found to have bilateral orbital mantle cell lymphoma on CT and MR imaging which was confirmed histopathologically. To our knowledge, there have been no previously described cases of bilateral mantle cell lymphoma in Graves' disease. Of particular radiologic interest, the left orbital mass presented in a bicompartmental fashion with a discreet intraconal component separated by a fat plane from an extraconal component that extended intraconally. In our review of radiologic literature, this presentation has not been described previously.

Small bowel obstruction due to a right-sided paraduodenal hernia: a case report.

Small bowel obstruction (SBO) diagnosed with abdominal computed tomography (CT) has been extensively studied in radiology literature. We present a case report of SBO due to a rare right-sided paraduodenal hernia diagnosed preoperatively on a non-contrast CT and confirmed surgically.

Multiple bilateral renal oncocytoms in a known case of tuberous sclerosis: a case report.

One of the rare patterns of renal involvement by tuberous sclerosis is oncocytoma. This is a report of a known male patient diagnosed with tuberous sclerosis. He was asymptomatic, but his periodic abdominal ultrasound examination revealed bilateral renal masses. CT and MRI confirmed the presence of these masses which were proven histopathologically to be multiple oncocytomas.

Pulmonary bullet embolism - a safe treatment strategy of a potentially fatal injury: a case report.

BACKGROUND: Vascular embolization of a projectile discharged from a weapon is a rare event. In this report a hunter's errant gunshot struck a farmer in the left chest. CASE REPORT: The projectile was lodged between the apex of the heart and the diaphragm. The patient was treated non-operatively and was discharged home only to return to the emergency department with chest pain and subsequent identification of the projectile in the left inferior pulmonary vein. Operative management consisted of a median sternotomy, cardiopulmonary bypass, and a pulmonary venectomy. CONCLUSION: He was subsequently discharged home and recovered uneventfully.