COVID-19-Associated Acute Asymmetric Hemorrhagic Necrotizing Encephalopathy: A Case Report.

Background: Coronavirus disease 2019 (COVID-19) has been associated with many neurological complications affecting the central nervous system. Purpose: Our aim was to describe a case of COVID-19 associated with a probable variant of acute necrotizing encephalopathy (ANE). Results: A 60-year-old man who presented with a 3-day history of dyspnea, fever, and cough tested positive for severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Five days following his admission, the patient was intubated secondary to respiratory failure. Following his extubation 16 days later, he was found to have a left-sided weakness. Magnetic resonance imaging (MRI) of the brain showed hemorrhagic rim-enhancing lesions involving the right thalamus, left hippocampus, and left parahippocampal gyrus. These lesions showed decreased relative cerebral blood flow on MR perfusion and restricted on diffusion-weighted imaging. These neuroimaging findings were consistent with ANE. The left-sided weakness gradually improved over the subsequent weeks. Conclusions: We concluded that COVID-19 can be associated with ANE, a condition believed to be the result of an immune-mediated process with activation of the innate immune system. Future studies must address whether biological drugs targeting the pro-inflammatory cytokines could prevent the development of this condition.

Diagnostic Performance and Clinical Impact of 68Ga-PSMA-11 PET/CT Imaging in Early Relapsed Prostate Cancer After Radical Therapy: A Prospective Multicenter Study (IAEA-PSMA Study).

Biochemical recurrence (BCR) is a clinical challenge in prostate cancer (PCa) patients, as recurrence localization guides subsequent therapies. The use of PET with prostate-specific membrane antigen (PSMA) provides better accuracy than conventional imaging practice. This prospective, multicenter, international study was performed to evaluate the diagnostic performance and clinical impact of PSMA PET/CT for evaluating BCR in PCa patients in a worldwide scenario. Methods: Patients were recruited from 17 centers in 15 countries. Inclusion criteria were histopathologically proven prostate adenocarcinoma, previous primary treatment, clinically established BCR, and negative conventional imaging (CT plus bone scintigraphy) and MRI results for patients with PSA levels of 4-10 ng/mL. All patients underwent PET/CT scanning with 68Ga-PSMA-11. Images and data were centrally reviewed. Multivariate logistic regression analysis was applied to identify the independent predictors of PSMA-positive results. Variables were selected for this regression model on the basis of significant associations in the univariate analysis and previous clinical knowledge: Gleason score, the PSA level at the time of the PET scan, PSA doubling time, and primary treatment strategy. All patients were monitored for a minimum of 6 mo. Results: From a total of 1,004 patients, 77.7% were treated initially with radical prostatectomy and 22.3% were treated with radiotherapy. Overall, 65.1% had positive PSMA PET/CT results. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment (P < 0.001). Treatment was modified on the basis of PSMA PET/CT results in 56.8% of patients. PSMA PET/CT positivity rates were consistent and not statistically different among countries with different incomes. Conclusion: This multicenter, international, prospective trial of PSMA PET/CT confirmed its capability for detecting local and metastatic recurrence in most PCa patients in the setting of BCR. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment. PSMA PET/CT results led to changes in therapeutic management in more than half of the cohort. The study demonstrated the reliability and worldwide feasibility of PSMA PET/CT in the workup of PCa patients with BCR.

What provokes a disappearing arachnoid cyst? - Case study and literature review.

OBJECTIVE: Intracranial Arachnoid cysts (AC) are stable cerebral spinal fluid (CSF)-filled sacs that can rarely undergo progressive shrinkage or disappearance throughout life. In this manuscript, we present a case of post-traumatic complete resolution of an AC, review the possible triggers of this phenomenon, and discuss the pathophysiological mechanisms behind them. METHODS: After presenting our case, we performed a literature review using the PubMed Database of all the reported cases of AC reduction or resolution (last updated in February 2021). Spontaneous cases were excluded. An analysis of the remaining cases (1985-2021) according to their inciting event, demographical, and clinical characteristics was then presented. RESULTS: 58 patients were identified, 33 of which spontaneously resolved. The remaining 25 were included in the survey in addition to the case we presented. The mean age was 20.2 years, average time to resolution was 25.3 months, with only two third of the cases showing complete disappearance of the AC. A central nervous system infection was the inciting cause of resolution in one infant (4%), a history of head trauma in 16 (62%) patients and an intracranial procedure in 9 (35%) patients. DISCUSSION: AC disappearance is a rare phenomenon that can occur spontaneously or after an inciting event. The cyst wall rupture and CSF flow perturbation theories seem to be the most applicable pathophysiological mechanisms in triggered AC resolution.

Case report of epithelioid osteoblastoma of the mandible: findings on positron emission tomography/computed tomography and review of the literature.

Epithelioid osteoblastoma is a clinically aggressive subtype of osteoblastoma that favors the mandible and the maxilla. Its histologic features lie on a spectrum between conventional osteoblastoma and low-grade osteosarcoma, thus making it difficult at times to confirm the diagnosis. It is known to have a high risk of recurrence after surgical resection, but it is a benign entity and does not have the propensity to metastasize. To our knowledge, there are no published reports on findings of epithelioid osteoblastoma on positron emission tomography/computed tomography (PET/CT). We report a case of a 25-year-old male patient with a diagnosis of epithelioid osteoblastoma of the mandible. The lesion exhibited significantly increased fluorodeoxyglucose uptake on PET/CT with a maximum standardized uptake value of 5.5. PET/CT is not specific in differentiating between malignant and benign bone lesions but may be necessary to rule out distant lesions when a confirmed diagnosis of epithelioid osteoblastoma cannot be obtained through histologic examination.

Thalamic volume and dimensions on MRI in the pediatric population: Normative values and correlations: (A cross sectional study).

BACKGROUND: Diagnoses of thalamic atrophy in children are based on experts' judgments. No normative measures exist for aiding objective diagnoses. Our aim was to determine normative two-dimensions(2D) and volume measurements of the thalamus in normally developing children. METHODS: MRI images of 245 patients were retrospectively collected. Only participants with normal brain MRIs were included in this cross-sectional study. Anterior-posterior (AP), transverse (T), and craniocaudal (C) diameters were measured. Volumetric masks of the thalamus were manually drawn, whereas volumetric measurements of the brain were automated. RESULTS: 124 patients were male (50.6%). We tabulated our measurements from birth until 18 years old. No significant differences in the thalamus measurements are found between the two hemispheres nor between sexes. The most remarkable increase in the thalamus volume and AP dimension is noted in the first four years of life, following which the values seem to stabilize. Craniocaudal diameters seem to increase in the first year of life, whereas transverse diameters increase until the age of 14 before plateauing. CONCLUSION: We report normative values of the thalamus in 2D and 3D from birth until 18 years of age. A rapid increase in the thalamic size is noted during the first four years of life followed by stabilization.

Swine Atrioventricular Node Ablation Using Stereotactic Radiosurgery: Methods and In Vivo Feasibility Investigation for Catheter-Free Ablation of Cardiac Arrhythmias.

BACKGROUND: Linear accelerator-based stereotactic radiosurgery delivered to cardiac arrhythmogenic foci could be a promising catheter-free ablation modality. We tested the feasibility of in vivo atrioventricular (AV) node ablation in swine using stereotactic radiosurgery. METHODS AND RESULTS: Five Large White breed swine (weight 40-75 kg; 4 females) were studied. Single-chamber St Jude pacemakers were implanted in each pig. The pigs were placed under general anesthesia, and coronary/cardiac computed tomography simulation scans were performed to localize the AV node. Cone beam computed tomography was used for target positioning. Stereotactic radiosurgery doses ranging from 35 to 40 Gy were delivered by a linear accelerator to the AV node, and the pigs were followed up with weekly pacemaker interrogations to observe for potential electrocardiographic changes. Once changes were observed, the pigs were euthanized, and pathology specimens of various tissues, including the AV node and tissues surrounding the AV node, were taken to study the effects of radiation. All 5 pigs had disturbances of AV conduction with progressive transition into complete heart block. Macroscopic inspection did not reveal damage to the myocardium, and pigs had preserved systolic function on echocardiography. Immunostaining revealed fibrosis in the target region of the AV node, whereas no fibrosis was detected in the nontargeted regions. CONCLUSIONS: Catheter-free radioablation using linear accelerator-based stereotactic radiosurgery is feasible in an intact swine model.

Quantifying the impact of using Coronary Artery Calcium Score for risk categorization instead of Framingham Score or European Heart SCORE in lipid lowering algorithms in a Middle Eastern population.

BACKGROUND: The use of the Coronary Artery Calcium Score (CACS) for risk categorization instead of the Framingham Risk Score (FRS) or European Heart SCORE (EHS) to improve classification of individuals is well documented. However, the impact of reclassifying individuals using CACS on initiating lipid lowering therapy is not well understood. We aimed to determine the percentage of individuals not requiring lipid lowering therapy as per the FRS and EHS models but are found to require it using CACS and vice versa; and to determine the level of agreement between CACS, FRS and EHS based models. METHODS: Data was collected for 500 consecutive patients who had already undergone CACS. However, only 242 patients met the inclusion criteria and were included in the analysis. Risk stratification comparisons were conducted according to CACS, FRS, and EHS, and the agreement (Kappa) between them was calculated. RESULTS: In accordance with the models, 79.7% to 81.5% of high-risk individuals were down-classified by CACS, while 6.8% to 7.6% of individuals at intermediate risk were up-classified to high risk by CACS, with slight to moderate agreement. Moreover, CACS recommended treatment to 5.7% and 5.8% of subjects untreated according to European and Canadian guidelines, respectively; whereas 75.2% to 81.2% of those treated in line with the guidelines would not be treated based on CACS. CONCLUSION: In this simulation, using CACS for risk categorization warrants lipid lowering treatment for 5-6% and spares 70-80% from treatment in accordance with the guidelines. Current strong evidence from double randomized clinical trials is in support of guideline recommendations. Our results call for a prospective trial to explore the benefits/risks of a CACS-based approach before any recommendations can be made.

Appropriateness and diagnostic yield of cardiac magnetic resonance imaging from a tertiary referral center in the Middle East.

PURPOSE: Cardiac magnetic resonance imaging (CMRI) is a novel non-invasive modality with many potential indications, and was recently introduced in Lebanon. We sought to assess the appropriateness and diagnostic yield of CMR studies performed at a tertiary referral center from the Middle East since the inception of the program. METHODS: All patients who underwent CMR studies between January 1(st) 2013 and June 18(th) 2014 were enrolled in this study. CMR reports were retrospectively reviewed. The study indication, clinical history, and findings were extracted and analyzed. The appropriateness of the study was judged according to the 2010 updated Asian Society of Cardiac Imaging guidelines. RESULTS: There were a total of 142 patients [mean age 42.1 (SD: 18) years, 24.6% females] that underwent CMR study. Two-thirds of studies were performed on an outpatient basis, and outside referrals constituted 16.2% of the entire cohort. The cardiologists referred 122 cases (86%) with main contribution from electrophysiology and imaging specialists. Of the 142 cases, 12 (8.4%) were not indicated and added little value. Of the remaining 130 appropriate studies (appropriateness level A8-A9), one-third had an incorrect diagnosis prior to CMR, and 8% had relevant findings that were missed on other studies but captured by CMR. Furthermore, CMR confirmed the diagnosis in 28% of the cases, provided relevant information on scar burden, shunt quantification, and ruled out infiltrative disease in the remaining patients. Also, CMR demonstrated the presence of scar in 45 of patients, among whom 20 (44%) had significant scar volume quantification (>5% of left ventricular myocardium). Finally, 9% of patients had a relevant extra-cardiac finding that needed further investigation. CONCLUSIONS: Despite the recent launch of the CMR program at our institution, the majority of studies were appropriately indicated, provided relevant data and were clinically useful. Inappropriate or uncertain studies did not provide relevant data, and should be further minimized to avoid unnecessary costs and downstream testing. Large prospective CMR database with clinical follow-up is needed to provide more insight about cardiovascular disease and outcomes in our population.

Fibroblastic and myofibroblastic tumors of the head and neck: comprehensive imaging-based review with pathologic correlation.

Fibroblastic and myofibroblastic tumors of the head and neck are a heterogeneous group of disorders characterized by the proliferation of fibroblasts, myofibroblasts, or both. These tumors may be further subclassified on the basis of their behavior as benign, intermediate with malignant potential, or malignant. There are different types of fibroblastic and myofibroblastic tumors that can involve the head and neck including desmoid-type fibromatosis, solitary fibrous tumor, myofibroma/myofibromatosis, nodular fasciitis, nasopharyngeal angiofibroma, fibrosarcoma, dermatofibrosarcoma protuberans, fibromatosis coli, inflammatory myofibroblastic tumor, ossifying fibroma, fibrous histiocytoma, nodular fasciitis, fibromyxoma, hyaline fibromatosis and fibrous hamartoma. Although the imaging characteristics of fibroblastic and myofibroblastic tumors of the head and neck are nonspecific, imaging plays a pivotal role in the noninvasive diagnosis and characterization of these tumors, providing information about the constitution of tumors, their extension and invasion of adjacent structures. Correlation with the clinical history may help limit the differential diagnosis and radiologists should be familiar with the imaging appearance of these tumors to reach an accurate diagnosis.

Effect of age and lordotic angle on the level of lumbar disc herniation.

It has been previously suggested in the literature that with aging, degenerative changes as well as disc herniation start at the lower lumbar segments, with higher disc involvement observed in an ascending fashion in older age groups. We conducted a study to investigate this correlation between age and level of disc herniation, and to associate it with the magnitude of the Lumbar Lordotic Angle (LLA), as measured by Cobb's method. We followed retrospectively lumbosacral spine MRI's of 1419 patients with symptomatic disc herniation. Pearson's correlation was used in order to investigate the relationship between LLA, age, and level of disc herniation. Student's t-test was applied to assess gender differences. Young patients were found to have higher LLA (R = 0.44, P < 0.0001) and lower levels of disc herniation (R = 0.302, P < 0.0001), whereas older patients had higher level herniation in lower LLA group (mean LLA 28.6° and 25.4°) and lower level herniation in high LLA group (mean LLA 33.2°). We concluded that Lumbar lordotic Cobb's angle and age can be predictors of the level of lumbar disc herniation. This did not differ among men and women (R = 0.341, P < 0.0001).

Value of sagittal fat-suppressed proton-density fast-spin-echo of the knee joint as a limited protocol in evaluating internal knee derangements.

PURPOSE: The aim of the study was to determine the accuracy and observer agreement in the assessment of internal knee derangement using sagittal fat-suppressed proton-density fast-spin-echo (FS PD-FSE) compared with combined sagittal T1-weighted spin-echo, dual-proton-density, and T2-weighted spin-echo sequences and with arthroscopy. METHODS: One hundred eighteen patients undergoing routine knee magnetic resonance (MR) imaging had additional imaging with sagittal FS PD-FSE sequences. Menisci, cruciate ligaments, extensor tendons (ETs), bone marrow, osteoarthritic changes, soft tissue edema, joint effusion, and incidental tumors were analyzed. Magnetic resonance images were independently reviewed by 2 radiologists. Fifty patients underwent knee arthroscopy. Statistical analysis compared both imaging protocols with each other and with arthroscopy. Intrareader and interreader agreements were evaluated using κ analysis. Both protocols were compared with arthroscopy. RESULTS: Intrareader agreement was very high except for readings of the posterior cruciate ligament, ETs, and cartilage. Intrareader agreement did not differ significantly between the 2 readers except for ETs, bone marrow, and cartilage. Interreader percent agreements were high using both protocols and were not significantly different between the 2 readers except for posterior cruciate ligament. Compared with arthroscopy, both methods showed almost identical results regarding sensitivity, specificity, positive predictive value, and negative predictive value, except for cartilage where FS PD-FSE had increased sensitivity, whereas the combined protocol had increased specificity. CONCLUSIONS: Sagittal FS PD-FSE is comparable to our regular MR protocol in assessing internal knee derangement with an overall agreement of at least 93% on all sites except cartilage. It was also comparable to arthroscopy in assessing the cruciate ligaments and menisci, but had a low specificity for cartilaginous derangements. It can replace our 3 sagittal series comprising T1- and T2-weighted and proton-density-spin-echo sequences, hence saving time and cost.

Evaluation of the appropriateness criteria for coronary computed tomography angiography in an academic medical center in a developing country: comparison of the 2006 and 2010 criteria.

BACKGROUND: The aims of this study are to analyze the risk profile and evaluate the appropriateness of patient referral to coronary CT angiography in a new MSCT laboratory in an academic medical center in a developing country. METHODS AND RESULTS: The study population consisted of 100 consecutive patients (mean age 53 ± 13 years, 83% males) who were referred to the new 64 slice MSCT laboratory at the American University of Beirut between July 2008 and July 2009. 52% of patients had chest pain and 48% were asymptomatic. By the 2006 ACCF criteria, only 8% of the referrals fitted the "Appropriate" criteria, 49% were "Inappropriate", and 43% were "Uncertain". The percentage of "Appropriate" indications increased from 8% by the 2006 criteria to 38% by the 2010 ACCF criteria. Framingham risk score (FRS) calculation showed a substantial percentage (46%) of patients to be at low risk, with 32% being at intermediate risk, and 22% at high risk. The prevalence of high calcium score (>400) (0% vs 22%, vs 27%, P < .001) and of obstructive CAD (4% vs 23% vs 40%, P < .001) increased steadily across the low, intermediate, and high FRS groups, respectively. CONCLUSIONS: There was a significant increase in the percentage of "Appropriate" indications for MSCT when comparing the 2010 to the 2006 ACCF appropriateness criteria. However, in spite of that, there was still significant deviation from the ACCF appropriateness criteria among patients referred for coronary CT angiography in this new MSCT laboratory in a developing country.

Toxocara canis myelitis: clinical features, magnetic resonance imaging (MRI) findings, and treatment outcome in 17 patients.

Toxocara myelitis is a rare disease. Few cases have been reported in the literature. Patients present with myelopathy, occasional eosinophilia in blood and cerebrospinal fluid (CSF), with abnormal signals on magnetic resonance imaging (MRI). In the current study we report 17 cases of isolated Toxocara myelitis from a single tertiary referral center in Lebanon, with description of the clinical presentation, laboratory data, MRI findings, and response to antihelminthic treatment. Clinical and laboratory data were collected for 17 patients who presented with evidence of spinal cord disease. The clinical presentation included sensory, motor, and autonomic dysfunction, predominantly in the lower extremities. Patients exhibited a subacute or chronic course; this was either slowly progressive or remitting-relapsing with mild to moderate disability. The patients underwent extensive blood and CSF workup as well as MRI of the spinal cord and brain. Only 2 patients had a high eosinophil count in the CSF, although blood eosinophilia was seen in 6 patients. All patients tested positive for Toxocara canis antibodies in the blood and CSF. MRI of the spinal cord revealed a single characteristic lesion in the spinal cord with fusiform enlargement that was isointense on T1-weighted images and hyperintense on T2-weighted images. Nodular enhancement was seen after gadolinium injection. Treatment with albendazole, with or without steroids, resulted in marked neurologic improvement and normalization of the MRI in all patients.The finding of a single inflammatory MRI lesion in the spinal cord with positive Toxocara canis serology in the blood and CSF in cases of subacute or chronic myelitis suggests the diagnosis of Toxocara myelitis, irrespective of the presence of eosinophilia. Antihelminthic treatment is associated with a good outcome.

Imaging in oncology.

Imaging plays an important role in the management of cancer patients, and in screening of asymptomatic individuals for early detection of cancer. This paper will review the clinical applications of oncologic imaging in the diagnosis, staging and followup in cancer patients and screening for cancer.

Variations in the referral patterns to stress nuclear imaging and stress echocardiography scans.

BACKGROUND: Stress myocardial perfusion imaging (MPI) and stress echocardiography (Echo) are commonly used for the noninvasive evaluation of patients with suspected coronary artery disease (CAD). Very few studies have compared the referral patterns to these imaging modalities in terms of the clinical profile of patients, reasons for referral, and type of referring physicians. METHODS AND RESULTS: This was a prospective study of 1,020 consecutive patients who were referred for stress MPI (429 patients) or stress Echo (591 patients) at the American University of Beirut Medical Center in the year of 2008. Patients referred to MPI were older and had a higher prevalence of diabetes, hypertension, hypercholesterolemia, smoking, and previous myocardial infarction, coronary angioplasty, or bypass surgery. There were more abnormal scans in the stress MPI group (24% vs 15%, P < 0.001), as well as a higher prevalence of ischemia (15% vs 7.6%, P < 0.001) and impaired left ventricular function with an ejection fraction <50% (11% vs 1.7%, P < 0.001). A higher percentage of stress Echo studies were self-referred by physicians who themselves interpret the scans (31% vs 19%, P < 0.001). CONCLUSION: Patients referred for stress MPI are at a higher risk than those referred for stress Echo having more CAD risk factors, more prior history of coronary events, and an older age. These findings have important implications in the interpretation of studies that compare the diagnostic and prognostic power of these two imaging modalities.

Catheter fracture and migration into the coronary sinus--an unusual migration site: case report and review.

Catheter fracture and cardiac migration are rare but known complications. Most reported cases have developed between the clavicle and the first rib as a consequence of catheter pinching between these two bony structures. To our knowledge, this is the first reported case of catheter migration into the coronary sinus. The broken fragment was successfully retrieved using loop-snare technique.

Left-sided cervical aortic arch associated with pseudocoarctation, aneurysm formation, and anomalous left brachiocephalic vein: appearance on MDCT and MR angiography.

Cervical aortic arch (CAA) is a rare congenital aortic anomaly. It can be associated with several cardiovascular abnormalities including aortic aneurysm, valvular disease, and pseudocoarctation. In this report, we present a case of CAA with combined association of both aneurysm formation and pseudocoarctation. This combination of anomalies is extremely uncommon, described in only 4 cases in the literature. In addition, our patient had an anomalous subaortic left brachiocephalic vein that, to our knowledge, was not previously described in the literature to be associated with CAA. The radiographic, multidetector computed tomography scan, and magnetic resonance angiography imaging findings are presented.

Radiology of terror injuries: the American University of Beirut Medical Center experience.

OBJECTIVE: This study aimed to report our experience with regard to imaging of mass casualty incidents (MCIs). SUBJECTS AND METHODS: Following a bomb attack, 150 casualties were referred to our hospital. Radiographs and nonenhanced CT scans were performed in 28 individuals. RESULTS: Major injuries were seen in 12 individuals, which were limited only to the brain (n=2), facial bones (n=2), and extremities and soft tissues (n=8). CONCLUSION: In MCIs, imaging should be fast, in order to help identify major injuries that need immediate management and to help in the triage of injured individuals.