Current Medical Imaging - Volume 18, Issue 8, 2022

Intramedullary lesions can be challenging to diagnose, given the wide range of possible pathologies. Each lesion has unique clinical and imaging features, which are best evaluated using magnetic resonance imaging. Radiological imaging is unique with rich, descriptive patterns and classic signs-which are often metaphorical. In this review, we present a collection of classic MRI signs, ranging from neoplastic to non-neoplastic lesions, within the spinal cord. The Differential Diagnosis (DD) of intramedullary lesions can be narrowed down by careful analysis of the classic signs and patterns of involvement in the spinal cord. Furthermore, the signs are illustrated memorably with emphasis on the pathophysiology, mimics, and pitfalls. Artificial Intelligence (AI) algorithms, particularly deep learning, have made remarkable progress in image recognition tasks. The classic signs and related illustrations can enhance a pattern recognition approach in diagnostic radiology. Deep learning can potentially be designed to distinguish neoplastic from non-neoplastic processes by pattern recognition of the classic MRI signs.

The application of Magnetic Resonance Imaging (MRI) have helped in different modalities for prostate cancer management, from early detection to treatment planning and follow-up, the evolution of MRI techniques allows to obtain not only anatomical but also functional information to take advantage of prostate cancer detection and staging while supplying prognostic and predictive biomarkers. This review presents conventional and advanced MRI techniques (known as multiparametric MRI) that allow functional and quantitative assessment of the normal prostate gland and its correlation with prostate cancer. Additional topics include the epidemiology of prostate cancer following the Global Burden Diseases Cancer Collaboration 2018, the clinical anatomy of the prostate gland, and the lower urinary tract; we also mention some aspects of the diagnosis performance in ultrasound. We end the review with a brief explanation about the anatomical foundation of external-beam planning radiotherapy.

Aortic cause of acute chest pain or abdominal pain can be easily overlooked. Unceasing wariness is required for timely diagnosis and prompt treatment. In such cases, cross-sectional imaging can detect the type of aortic involvement, its site, extent, complications, and could help clinicians decide on a management method and prognosticate the condition. This pictorial illustration represents a spectrum of life-threatening conditions involving the aorta in a non-traumatic setting.

Background: Postoperative brain edema is a common complication in patients with high-grade glioma after craniotomy. Both Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) are applied to diagnose brain edema. Usually, MRI is considered to be better than CT for identifying brain edema. However, MRI is not generally applied in diagnosing acute cerebral edema in the early postoperative stage. Whether CT is reliable in detecting postoperative brain edema in the early stage is unknown. Objective: This study aimed at investigating the agreement and correlation between CT and MRI for measuring early postoperative brain edema. Methods: Patients with high-grade glioma who underwent craniotomy in the Beijing Tiantan hospital from January 2017 to October 2018 were retrospectively analyzed. The region of interest and operative cavity were manually outlined, and the volume of postoperative brain edema was measured on CT and MRI. Pearson correlation testing and the Intraclass Correlation Coefficient (ICC) were used to evaluate the association and agreement between CT and MRI for detecting the volume of postoperative brain edema. Results: Twenty patients were included in this study. The interrater agreement was perfect for detecting brain edema (CT: Κ=1, ICC=0.977, P<0.001; MRI: Κ=0.866, ICC=0.963, P<0.001). A significant positive correlation and excellent consistency between CT and MRI were found for measuring the volume of brain edema (rater 1: r=0.97, ICC=0.934, P<0.001; rater 2: r=0.97, ICC=0.957, P<0.001). Conclusion: Substantial comparability between CT and MRI is demonstrated for detecting postoperative brain edema. It is reliable to use CT for measuring brain edema volume in the early stage after surgery.

Background: Cerebrovascular Reactivity (CVR), as measured using perfusion Single Photon Emission Computed Tomography (SPECT), is an important indicator for the treatment and prognosis of cerebrovascular disease, but there are a few studies on acute stroke or small vascular disease using SPECT. Objective: This study evaluated the regional severity with quantitatively determined CVR in patients with acute stroke. Methods: Fifty-eight patients who took brain SPECT images were selected to localize quantitative CVR values. The severity of the disease (Grade 1 to 4) was determined through image-based clinical assessment in the absence and presence of a CVR map, and their results were compared. Results: In 1st diagnosis without the map, the mean CVR values of Grades 2 and 3 were -6.07 % and -9.12 %, respectively (P=0.034), while they were -4.78 % and -12.34 % in 2nd diagnosis with the map, respectively (P<0.001), suggesting that the CVR difference with the map was much more pronounced than without the map. Furthermore, in the ROC analysis, the diagnostic sensitivity between Grades 2 and 3 in the 2nd diagnosis (AUC=0.899, P<0.001) was substantially greater than the 1st diagnosis (AUC=0.646, P=0.048). Conclusion: This study demonstrated that the quantitative CVR maps could reinforce the clinical evaluation of cerebral severity by showing that they can provide statistically significant results between severity and CVR. Furthermore, this study was the first to evaluate the effectiveness of quantitative CVR by examining the difference in the presence or absence of CVR in patients with acute stroke.

Background: Microwave imaging is one of the emerging non-invasive portable imaging techniques, which uses nonionized radiations to take a detailed view of biological tissues in the microwave frequency range. Brain stroke is an emergency caused by the interruption of the blood supply into parts of the brain, leading to the loss of millions of brain cells. Imaging plays a major role in stroke diagnosis for prompt treatment. Objective: This work proposes a computationally efficient algorithm called the GPR algorithm to locate the blood clot with a size of 10 mm in microwave images. Methods: The electromagnetic waves are radiated, and backscattered reflections are received by Antipodal Vivaldi antenna with the parasitic patch (48 mm*21 mm). The received signals are converted to a planar 2D image, and the depth of the blood clot is identified from the B-scan image. The novelty of this work lies in applying the GPR algorithm for the accurate positioning of a blood clot in a multilayered head tissue. Results: The proposed system is effectively demonstrated using a 3D M.E.M. simulator, and simulated results are verified in a Vector network analyzer (E8363B) with an experimental setup. Conclusion: This is an alternative safe imaging modality compared to present imaging systems (T.C.T. and MRI).

Background: Dental implants are considered the first option to replace missing teeth. Alveolar bone resorption gradually progresses following tooth extraction leading to loss of vertical bone dimension for implant placement. The lateral window approach is the most commonly used procedure to treat vertical bone loss. Objective: The aim of the present study is to evaluate the Lateral Wall Thickness (LWT) of the maxillary sinus and determine the influence of gender and side on maxillary LWT. Methods: This study involved a cross sectional retrospective study. Cone- beam computed tomography data were collected from 99 patients with a total of 198 maxillary sinuses that met the inclusion criteria. The patient age ranged between 18 to 35 years. On the selected sagittal section, the points of measurement are determined by a perpendicular line at 5 mm from the lowest point of the sinus floor. Measurements were taken at four different areas; first premolar (P1), second premolar (P2), first molar (M1), and second molar (M2). Descriptive statistics were used to calculate mean lateral wall thickness for each tooth, and student’s t-test was used to test the effect of gender and side on maxillary LWT. Results: The greatest mean LWT was observed around the left first maxillary molar (2.43±0.82), while the lowest mean LWT was observed around the right second maxillary premolar (1.62±0.61). There was no significant difference in the LWT around any tooth (M1 p=0.56, M2 p=0.92, P1 p=0.14, P2 p=0.19). Conclusion: There was no significant difference in both males and females of the lateral wall thickness in the left and right side of maxillary sinus.

Background: The typical findings of COVID-19 pneumonia include multilobar groundglass opacities and consolidation areas observed predominantly in the basal and peripheral parts of both lungs in computed tomography. Objective: The current study aimed to correlate indeterminate lesions of COVID-19 pneumonia detected on computed tomography with the results of the reverse transcription-polymerase chain reaction (RT-PCR) test. Methods: Patients with high-resolution computed tomography images that were reported to contain indeterminate lesions in terms of COVID-19 pneumonia were included retrospectively in the study. The lesions were categorized and the patterns were classified. The RT-PCR-positive and the RTPCR- negative patients were compared. P<0.05 was accepted as the statistical significance limit. Results: The RT-PCR-positive patients exhibited a higher rate of peripheral lesions. Limited consolidation areas were not detected in the RT-PCR-positive patients. In the RT-PCR-negative patients, the rates of acinar nodules and the tree-in-bud pattern were significantly higher. The RTPCR- negative patients had higher nodular contour features and lesion coalescence. In the subgroup consisting of lesions with ground-glass opacities and/or ground-glass opacity around the nodule, the rate of nodular contour positivity was significantly higher in the RT-PCR- positive patients. Conclusion: COVID-19 pneumonia should be suspected when peripheral indeterminate lesions are detected. When indeterminate lesions, such as tree-in-bud pattern, acinar nodules and limited consolidation area are detected, alternative diagnoses should be considered first, even if there are ground glass opacities accompanying these lesions.

Introduction: To investigate the Computed Tomography (CT) imaging characteristics and dynamic changes of COVID-19 pneumonia at different stages. Methods: Forty-six patients infected with COVID-19 who had chest CT scans were enrolled, and CT scans were performed 4-6 times with an interval of 2-5 days. Results: At the early stage (n=25), ground glass opacity was presented in 11 patients (11/25 or 44.0 %) and ground glass opacity mixed with consolidation in 13 (13/25 or 52.0 %) in the lung CT images. At the progressive stage (n=38), ground glass opacity was presented in only one patient (1/38 or 2.6 %) and ground glass opacity mixed with consolidation in 33 (33/38 or 86.8 %). In the early improvement stage (n=38), the imaging presentation was ground glass opacity alone in three patients (3/38 or 7.9 %) and ground glass opacity mixed with consolidation in 34 (34/38 or 89.5 %). In the late improvement (absorption) stage (n=33), the primary imaging presentation was ground glass presentation in eight patients (8/33 or 24.2 %) and ground glass opacity mixed with consolidation in 23 (23/33 or 69.7 %). The lesion reached the peak at 4-16 days after disease onset, and 26 (26/38 or 68.4 %) patients reached the disease peak within ten days. Starting from 6 to 20 days after onset, the disease began to be improved, with 30 (30/38 or 78.9 %) patients being improved within 15 days. Conclusion: COVID-19 pneumonia will progress to the peak stage at a mediate time of seven days and enter the improvement stage at twelve days. Computed tomography imaging of the pulmonary lesion has a common pattern from disease onset to improvement and recovery and provides important information for evaluation of the disease course and treatment effect.

Objective: The aim of the study was to investigate the accuracy of breast Magnetic Resonance Imaging (MRI) for evaluating residual tumor size following Neoadjuvant Chemotherapy (NAC) and to identify clinicopathologic and MRI features affecting its accuracy. Materials and Methods: We retrospectively assessed 109 women who underwent preoperative Dynamic Contrast-Enhanced (DCE) MRI following NAC and subsequent surgery between April 2016 and August 2020. Preoperative MRI features, including Breast Imaging Reporting and Data System lexicon characteristics, size of residual enhancing lesion, tumor shrinkage pattern, and clinicopathologic features, were investigated, and MRI and pathology findings were compared. Results: Residual tumor size on MRI showed high agreement with residual invasive tumor size on pathologic examination (ICC, 0.808, p<0.001). The residual tumor size measured by MRI and final pathologic size were concordant in 63/109 cases (57.8%), while MRI overestimated the size in 35/109 cases (32.1%). For estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors, MRI tended to underestimate the residual tumor size compared with HER2-positive cancers (p=0.002) and triple-negative cancers (p=0.12). On MRI, tumors with concentric shrinkage patterns after NAC showed less size discrepancy with final pathologic tumor size than those with non-concentric patterns (p=0.026). Conclusion: In ER-positive/HER2-negative cancers, MRI tends to underestimate the residual tumor size, compared to in other subtypes. Tumors with concentric shrinkage patterns after NAC showed less MRI/pathology size discrepancy.

Background: Nonalcoholic fatty liver disease has attracted considerable attention with continuously increasing morbidity. Objective: To evaluate the aortic distensibility in patients with non-diabetic and hypertension-type Nonalcoholic Fatty Liver Disease (NAFLD) through Dual-Source Computed Tomography (DSCT). Methods: 120 patients with NAFLD (experimental group) and 30 healthy subjects (control group) were consecutively enrolled in the study. In the two groups, aortic distensibility was calculated as D = ΔA/(A0 ×Δp). Record fasting insulin, fasting blood glucose, fasting lipid status, age, heart rate, waist circumference, systolic blood pressure, and diastolic blood pressure. Calculate homeostasis model assessment of insulin resistance (HOMA-IR) and Body Mass Index (BMI). A comparative analysis between the two groups was carried out, followed by a correlation analysis between D value and risk factors. Results: D value and liver attenuation of the patients in the NAFLD group were significantly reduced relative to those in the control group (2.24±0.63×10^-3 mmHg^-1 vs. 3.19±0.86×10^-3 mmHg^-1, P<0.001 and 41±6HU vs. 53±5HU, P<0.001, respectively) and their fasting blood glucose, fasting insulin, triglyceride, low-density lipoprotein, aspartate aminotransferase, alanine transaminase, HOMA- IR, and BMI were higher than those in the control group. Liver attenuation, HOMA-IR, age, and BMI were significantly correlated with D value in the NAFLD group. The stepwise multiple linear regression analysis indicates that liver attenuation and HOMA-IR were the significant risk factors for D value (β coefficient =0.43, P =0.001, and β coefficient =-0.33, P =0.02, respectively). Conclusion: Patients with NAFLD suffer from a reduction in aortic distensibility, and insulin resistance may play a significant role in the early atherosclerosis stage.

Introduction: The medulla oblongata is the lowest segment of the brain stem, located adjacent to the spinal cord, with a complex anatomical structure. Thus, a small injury to the medulla oblongata can show complex clinical manifestations. Case Presentation: A patient experienced dysesthesia, which manifested as numbness in her right lower limb and decreased temperature sense, and dizziness 20 days before admission. The numbness worsened 1 week before admission, reaching the right Thoracic (T) 12 dermatomes. Her thermoception below the T12 dermatomes decreased, and the degree of dizziness increased, accompanied by nausea and vomiting. Magnetic Resonance Imaging (MRI) of the neck, chest, and abdomen performed at a local hospital showed no abnormalities. MRI of the brain was performed after admission. One week after admission, she experienced a severe headache in the upper left periorbital area. The numbness extended to T4, and thermoception decreased below T4. Diagnosis: Lateral medullary infarction. Interventions: Anti-platelet aggregation and mitochondrial nutritional therapies were performed along with treatments for improving circulation and establishing collateral circulation. Outcomes: The intensity of limb numbness decreased, and the symptoms of headache and dizziness resolved. Conclusion: Lesions leading to segmental sensory disorders can occur in the medulla oblongata. Ipsilateral headaches with contralateral segmental paresthesia can be a specific sign of lateral medullary infarction.

Background: Spinal Cord Infarction (SCI) is difficult to diagnose because of its rarity, unknown etiology, and unestablished diagnostic criteria. Additionally, the timeline of SCI has not been studied in detail, as few studies using Diffusion-Weighted Image (DWI) sequences of the spine of a small target population have been previously conducted. Case Study: A 56-year-old male with underlying arrhythmia suddenly developed visual field defects on the right side, pain in the left upper extremity, and a tingling sensation in the left hand. Brain Magnetic resonance imaging (MRI) revealed acute to subacute stages of multifocal brain infarction. On additional cervical spinal MRI, it showed atypical MRI findings of SCI, considered late acute to early subacute phase, which were similar to those seen in the acute phase of multiple sclerosis (MS). Additional DWI revealed restricted diffusion. From these findings, it could be inferred that the patient’s SCI occurred at the same time as the multifocal brain infarctions caused by atrial fibrillation. Conclusion: A DWI sequence of spine MRI could be helpful in the diagnosis of acute to subacute phase SCI and in differentiating with acute MS.

Background: A Solitary Fibrous Tumor (SFT) is a distinct mesenchymal neoplasm. It was originally described as a tumor localized to the pleura but was later reported in several other anatomic sites and exhibited a wide spectrum of histological features. Owing to its rarity, the diagnosis of extrapleural SFT is challenging and requires an integrated approach comprising specific clinical, imaging, histological, and immunohistochemical findings. Case Presentation: Herein, we report the imaging findings of a rare case of SFT arising from bilateral ovaries confirmed by surgical excision and histological examination. No adjuvant radiotherapy or chemotherapy was given to the patient, and she was disease-free with no evidence of recurrence or metastasis at the 96-month postoperative follow-up. Although it mostly follows a favorable course, SFT is notoriously difficult for prognostication because of its propensity for late relapse or even metastases in 10-39% of cases. Conclusion: Close follow-up is recommended because of the limited information on its long-term behavior.