Normal Anatomic Structures Research Articles

Application of artificial intelligence in thoracic radiology: A narrative review (Application of AI in thoracic radiology).

Thoracic radiology is a primary field where artificial intelligence (AI) has been extensively researched. Recent advancements in AI demonstrate potential improvements in radiologists' performance. AI facilitates the detection and classification of abnormalities, as well as the quantification of both normal and abnormal anatomical structures. Furthermore, it enables prognostication based on these quantitative values. In this review article, the recent achievements of AI in thoracic radiology will be reviewed, mainly focused on deep learning, and the current limitations and future directions of this cutting-edge technique will be discussed.

Diagnostic accuracy and image quality evaluation of ultrashort echo time MRI in the lungs.

This study evaluates the diagnostic accuracy of ultrashort echo time (UTE)-MRI for detecting pulmonary nodules and image quality. A total of 46 patients at our hospital underwent unenhanced computed tomography (CT) and UTE-MRI. The image quality and number of nodules detected using CT were used as the gold standards. Three diagnostic radiologists independently recorded the image quality (visibility and sharpness of normal anatomical structures) of the CT and UTE images and the number of pulmonary nodules detected. The diagnostic accuracy, subjective image quality, and consistency between observations were statistically analyzed. Among 46 patients, 36 (78.2%) had pulmonary nodules on CT images, whereas 10 patients (21.7%) had no pulmonary nodules. A total of 48 lung nodules were detected, 3 of which were ground-glass opacities. UTE-MRI revealed 46 lung nodules. Compared with CT, the sensitivity of all MRI readers for detecting lung lesions was 95.8%, and the 3-observer agreement was nearly perfect (P < .001, Kendall Wa [Kender Harmonious Coefficient] = 0.913). The overall image quality score of the observers was high, ranging from good to excellent, and the consistency of the subjective UTE-MRI image quality was good (Kendall Wa = 0.877, P < .001). For tracheal display, the subsegment of the bronchus was displayed, and the wall of the tube was clearly displayed. The difference in the Wa values between the observers was 0.804 (P < .001), indicating strong consistency. For blood vessels, subsegment blood vessels could also be displayed with clear walls and uniform signals (Kendal Wa = 0.823, P < .001), indicating strong consistency. Compared to CT, UTE-MRI can detect pulmonary nodules with a high detection rate, relatively good image quality, and strong consistency between observers. The development of UTE-MRI can provide a novel imaging method for the detection and follow-up of pulmonary nodules and diagnosis of pneumonia by reducing ionizing radiation.

Temporal Changes on Postgadolinium MR Vessel Wall Imaging Captures Enhancement Kinetics of Intracranial Atherosclerotic Plaques and Aneurysms.

Analysis of vessel wall contrast kinetics (ie, wash-in/washout) is a promising method for the diagnosis and risk-stratification of intracranial atherosclerotic disease plaque (ICAD-P) and the intracranial aneurysm walls (IA-W). We used black-blood MR imaging or MR vessel wall imaging to evaluate the temporal relationship of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws compared with normal anatomic reference structures. Patients with ICAD-Ps or IAs who underwent MR vessel wall imaging with precontrast, early postcontrast (5-15 minutes), and delayed postcontrast (20-30 minutes) 3D T1-weighted TSE sequences were retrospectively studied. ROIs of a standardized diameter (2 mm) were used to measure the signal intensities of the cavernous sinus, pituitary infundibulum, temporalis muscle, and choroid plexus. Point ROIs were used for ICAD-Ps and IA-Ws. All ROI signal intensities were normalized to white matter signal intensity obtained using ROIs of 10-mm diameter. Measurements were acquired on precontrast, early postcontrast, and delayed postcontrast 3D T1 TSE sequences for each patient.ajnr;45/9/1206/T1T1T1Table 1:MR-VWI parameters for ICAD-Ps and IAsParameterValueSequence3D TSEScan planeAxialFOV (mm)160TR/TE (ms)800/28-32BW (Hx/pixel)370θ120Acceleration2ETL42Matrix acquisition0.5 mm ×0.5 mmMatrix recon0.5 mm ×0.5 mmNo. of slices/thick120/0.5Note:-FOV indicates field of view; TR, the repetition time; TE, the echo time; BW, bandwidth; ETL, echo train length; Matrix recon, matrix reconstruction. Ten patients with 17 symptomatic ICAD-Ps and 30 patients with 34 IA-Ws were included and demonstrated persisting contrast uptake (P < .001) of 7.21% and 10.54% beyond the early phase (5-15 minutes postcontrast) and in the delayed phase (20-30 minutes postcontrast) on postcontrast MR vessel wall imaging. However, normal anatomic reference structures including the pituitary infundibulum and cavernous sinus demonstrated a paradoxical contrast washout in the delayed phase. In both ICAD-Ps and IA-Ws, the greatest percentage of quantitative enhancement (>70%-90%) occurred in the early phase of postcontrast imaging, consistent with the rapid contrast uptake kinetics of neurovascular pathology. Using standard MR vessel wall imaging techniques, our results demonstrate the effects of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws with extended accumulating enhancement into the delayed phase (> 15 minutes) as opposed to normal anatomic reference structures that conversely exhibit decreasing enhancement. Because these relative differences are used to assess qualitative patterns of ICAD-P and IA-W enhancement, our findings highlight the importance of standardizing acquisition time points and MR vessel wall imaging protocols to interpret pathologic enhancement for the risk stratification of cerebrovascular pathologies.

Pictorial review of the diagnosis of muscle-invasive bladder cancer using vesical imaging-reporting and data system (VI-RADS).

The Vesical Imaging-Reporting and Data System (VI-RADS) is a standard magnetic resonance imaging (MRI) and diagnostic method for muscle-invasive bladder cancer that was published in 2018. Several studies have demonstrated that VI-RADS has high diagnostic power and reproducibility. However, reading VI-RADS requires a certain amount of expertise, and radiologists need to be aware of the various pitfalls. MRI of the bladder includes T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced imaging (DCEI). T2WI is excellent for understanding anatomy. DWI and DCEI show high contrast between the tumor and normal anatomical structures and are suitable for staging local tumors. Bladder tumors are classified into five categories according to their size and morphology and their positional relationship to the bladder wall based on the VI-RADS diagnostic criteria. If the T2WI, DWI, and DCEI categories are the same, the category is the VI-RADS category. If the categories do not match, the DWI category is the VI-RADS category. If image quality of DWI is not evaluable, the DCEI category is the final category. In many cases, DWI is dominant, but this does not mean that T2WI and DCEI can be omitted from the reading of the bladder. In this educational review, typical and atypical teaching cases are demonstrated, and how to resolve misdiagnosis and the limitations of VI-RADS are discussed. The most important aspect of VI-RADS reading is to practice multiparametric reading with a solid understanding of the characteristics and role of each sequence and an awareness of the various pitfalls.

MobileNet and Streamlit Applications for Classification and Prediction of MRI-Based Types of Brain Tumor

The rapid proliferation of abnormal cells within the cerebrum and its surrounding areas leads to the formation of tumor cells with intricate and challenging patterns. Consequently, relying solely on magnetic resonance imaging (MRI) for brain tumor detection presents complexities due to the need for precise identification amidst normal anatomical structures and potentially anomalous tissues. Recognizing the urgency of early and precise diagnosis in combating brain cancers, this paper proposes a methodology for classifying and predicting MRI based brain tumor types using MobileNet through a Streamlit application. Initially, the input image dataset undergoes preprocessing to enhance image quality, facilitated by a Gaussian filter. Subsequently, the FCM segmentation technique is employed to accurately delineate tumors’ size, location, and morphology. Finally, feature extraction and classification are performed utilizing the MobileNet framework, a deep learning method known for its accuracy and efficiency, particularly in medical image segmentation. Performance evaluation metrics such as precision, recall, and accuracy are computed, culminating in the calculation of the F score to assess the model’s effectiveness. This work leverages the Streamlit environment, a Python platform for developing web based interactive applications, to facilitate seamless user interaction. Ultimately, the predicted output images depicting various brain tumor types glioma, meningioma, pituitary, and absence of tumor are displayed within the Streamlit software interface. By offering a swift and precise means of disease classification, this approach aids healthcare professionals in promptly identifying tumor afflicted patients while streamlining computational overhead. The proposed classifier shows the highest specificity of 94.5 % and sensitivity of 97.6%.

A New Option to Preserve Esthetics in Perioral Defect Reconstruction With Normal Anatomical Structures: Bipedicled Preexpanded Forehead Flap With Random Skin Flap Extension.

Plastic surgeons charged with reconstructing extensive perioral defects face dual challenges of functional restoration and esthetic considerations. While forehead flaps are commonly used to reconstruct perioral defects, in cases involving partial upper lip defects where normal anatomical structures are preserved, traditional forehead flaps may compromise esthetics. This study aimed to address this issue by employing bipedicled preexpanded forehead flaps based on the frontal branches of the superficial temporal artery (hereafter, "STA-bfb-based preexpanded forehead flap") with random flap extensions to repair perioral defects. Between April 2004 and July 2020, 7 patients (5 males and 2 females; 6 had post-burn facial scars involving the entire lower lip and part of the upper lip, and 1 presented with noma sequelae) underwent perioral defect reconstruction using this approach. Tissue expanders were placed in the forehead donor area, and an STA-bfb-based preexpanded forehead flap with random flap extensions was used to repair the perioral defect. The flap pedicle was divided into 3 weeks. All flaps remained viable with no perfusion-related complications. At follow-up 12 to 96 months later, the color and texture of the flaps demonstrated excellent compatibility with the surrounding skin, suggesting that the use of an STA-bfb-based preexpanded forehead flap with random skin flap extensions is a reliable method for repairing perioral defects. The authors' results have implications for plastic surgeons seeking a solution for challenging perioral defect reconstructions, balancing the need for esthetic outcomes with functional restoration.

Low-dose versus standard-dose normal temporal bone CT in children: a comparison study

ObjectiveTo compare the image quality of normal anatomical structures and radiation dose on low-dose (LDCT) and standard-dose (SDCT) temporal bone CT in children.MethodsThe study included 45 LDCT (80 kV and 130 mAs) and 45 SDCT (120 kV and 170 mAs) scans in children, 1–15 years of age. LDCT and SDCT scans were analyzed on H60s and H70h reconstruction kernels, respectively. Two readers assessed the image quality for 25 anatomical structures, using a 5-point scale. A score of 3 and above was considered “sufficient” and 2 and below was considered “insufficient” image quality. Image noise, contrast, age and size-specific effective doses were calculated.ResultsDespite an increase in image noise on LDCT, image quality remained sufficient for most structures owing to increased image contrast. The median effective dose on LDCT, calculated with age-specific conversion factor, decreased by 72.9% and that calculated with size-specific conversion factor decreased by 81.8% compared to the dose on SDCT.ConclusionLDCT provides comparable image quality for evaluation of temporal bone with significant reduction in radiation dose in children.

Pearls and Pitfalls in Applying PI-RADS 2.1

AbstractThe use of Prostate Imaging Reporting and Data System (PI-RADS) with multiparametric magnetic resonance imaging (MRI) has significantly improved the detection of clinically significant prostate cancer (csPCa), but there are certain challenges that the reader may face. This review provides an overview of the pitfalls associated with the PI-RADS system for multiparametric prostate MRI (mpMRI), with suggestions/pearls to help overcome these pitfalls.PI-RADS assessment is hindered by several causes of false positives (FPs) and false negatives (FNs). In addition, there is wide variability in the positive predictive value (PPV) of the PI-RADS system across different centers, highlighting the need for improvement. While the negative predictive value (NPV) for csPCa is generally high, variations exist.This review discusses the pitfalls contributing to FNs, including MRI artifacts, such as susceptibility and motion artifacts. Techniques to optimize image acquisition, such as switching the phase encoding direction and reducing bowel peristalsis, are suggested to mitigate these artifacts. Improper b-value selection for diffusion-weighted imaging (DWI) is another pitfall, emphasizing the importance of using high b-values (≥1,400 s/mm2) to optimize neoplasm detection. Similarly, optimizing window settings to visualize csPCa, correctly positioning the endorectal coil, awareness of rare variants like mucinous adenocarcinoma and cribriform adenocarcinoma, and distinguishing central zone tumors from normal central zone are discussed.This article highlights the common pitfalls causing FPs, such as benign pathologies like prostatitis, granulomatous prostatitis, prostatic abscess, stromal BPH nodules, extruded BPH nodules, and prostatic calcifications. It also discusses the pitfalls related to normal anatomical structures, including the central zone, anterior fibromuscular stroma, thickened surgical capsule, neurovascular bundle, and periprostatic venous plexus. Techniques for carefully evaluating these entities' morphology and distribution of signal abnormalities are described to avoid overdiagnosing these as PCa. The article also addresses the pitfalls related to postintervention changes, including postbiopsy hemorrhage and artifacts caused by the UroLift procedure, while providing recommendations for managing these challenges.Finally, the pitfalls that may be encountered during staging, including evaluation for extraprostatic extension, and pelvic nodal and osseous metastases, are highlighted.

Blending Conventional Learning Approach with Contemporary Visualization Technologies: Prerequisite Toward Evidence-Based Surface Anatomy.

Proficiency in surface anatomy knowledge plays a pivotal role in fostering complication-free and efficacious clinical practice across a wide spectrum of healthcare specialties. This comprehensive understanding and adept utilization of surface anatomy principles serve as the linchpin for deciphering normal anatomical structures within medical imaging and the aptitude to articulate the topographical attributes, visual characteristics, and interrelations of palpable anatomical entities. Despite the advent of advanced direct visualization techniques, such as ultrasound guidance, which assist in interventional procedures, clinicians have not relinquished the indispensable requirement for pertinent surface anatomy knowledge to ensure the successful and secure execution of procedures. Regrettably, evidence-based surface anatomy remains an underemphasized facet in the pedagogy of anatomical sciences. The current narrative review underscores the various methodologies employed in imparting surface anatomy education to students. However, it is noteworthy that no singular, unequivocal best practice has emerged for the teaching and acquisition of surface anatomy knowledge. Therefore, as custodians of anatomical education, there is a pressing need to innovate and amalgamate contemporary pedagogical approaches with state-of-the-art technologies to furnish students with evidence-based surface anatomy insights, thereby enhancing comprehension, retention, and the lasting utility of this essential domain of medical knowledge.

Posterior Fossa Anatomy for Microvascular Decompression Surgery

In most microvascular decompression surgeries, surgical maneuvers are performed within normal anatomical structures without any neoplasms. Thus, detailed anatomical knowledge is essential to perform safe and efficient procedures. "Rule of 3" by Rhoton AL Jr. is helpful for understanding not only the anatomy of the posterior fossa but also the three neurovascular compression syndromes. The cerebellar arteries and posterior fossa veins have substantial variability, but a basic understanding of their typical patterns is useful to explore individual cases. To use adequate surgical approaches through the cerebellar tentorial or petrosal surface in individual trigeminal neuralgia surgeries, anatomical knowledge of the bridging veins on the tentorial(the bridging veins into the tentorial sinus)and petrosal surfaces(the superior petrosal vein)is crucial. Fissure openings help to minimize cerebellar retraction, similarly to the sylvian fissure dissection in supratentorial surgeries.

Effects of Endoscopic Sinus Surgery on Olfactory Function.

To review the effects of endoscopic sinus surgery and endonasal approaches to the skull base on olfaction. Advancements in endonasal endoscopic approaches to the sinuses and skull base allow for direct treatment of a variety of sinonasal and skull base diseases. However, these extended approaches will often require manipulation of normal anatomical structures and the olfactory neuroepithelium. Depending on the planned procedure and extent of disease, the prognosis of olfactory perception can vary significantly among patients. Endoscopic sinonasal surgical procedures may impact olfaction. Optimizing olfactory function requires proper surgical techniques, gentle handling of tissue, and perioperative care. Surgeons must discuss objectives and manage patient expectations. Routine olfactory assessment is crucial in surgical work-up and follow-up. Preserving anatomical structures while addressing the obstruction of the olfactory cleft helps to prevent decreased olfactory threshold. However, smell identification and discrimination do not always correlate with sinonasal anatomy.

Optimizing the Approach to STA-MCA Bypass Surgery and Reducing Wound Complications

The treatment of complex intracranial aneurysms with bypass surgery using 2 branches of the superficial temporal artery (STA) proves to be an effective surgical option. However, the harvest of these 2 STA branches, combined with a pterional craniotomy, carries the potential risk of delayed wound healing of the skin flap. This study undertook a retrospective analysis to examine and identify the factors associated with this delayed wound healing. A total of 56 consecutive cases, including both ruptured and unruptured complex intracranial aneurysms, that underwent bypass surgery with 2 branches of the STA, were analyzed retrospectively. Major delayed wound healing was observed in 6 (10.7%) cases. Univariate analysis demonstrated significant associations with the following factors: rupture (P= 0.023), presence of diabetes mellitus (P= 0.028), large craniotomy size (P= 0.012), and the type of skin incision (P ≤ 0.001). Age (P= 0.283), sex (P= 0.558), body mass index (P= 0.221), and other blood test parameters did not demonstrate any statistical significance. Similarly, the presence of a dominant frontal branch (P= 0.515) or a low-positioned frontal branch (P= 0.622) did not reveal statistically significant results. In the treatment of complex intracranial aneurysms, where harvesting of the 2 STA branches is involved with a pterional craniotomy, producing a smaller skin flap (L- or T-shaped incision) is effective in minimizing the risk of delayed wound healing. The process of harvesting the STA and closing the wound demands meticulous care, taking into consideration the normal anatomical structures and the subdermal vascular plexus of the scalp.

Characteristics of nutritional status in patients with chronic kidney disease

Chronic kidney disease is kidney damage that persists for three months or more due to the action of various etiological factors, the anatomical basis of which is the process of replacement of normal anatomical structures with fibrosis, leading to its dysfunction. This nosology is quite common in the modern world; it can progress and lead to disability of patients and a decrease in their quality of life. The mortality rate for this disease also remains high. About 3/4 of patients with this pathology have a terminal stage of the process, which is characterized by the development of protein-energy deficiency (due to uremia, malnutrition, acidosis and persistent inflammatory process), which significantly worsens the prognosis. Currently, the available literature contains a small number of works devoted to this problem, therefore an important part of the management of patients with chronic kidney disease (especially those on hemodialysis) is the assessment and correction of nutritional status. In this article, the authors highlight aspects of the development of protein-energy malnutrition, its possible methods of diagnosis and correction. Electrolyte disturbances, especially hyperkalemia and hyperphosphatemia, are also common complications of chronic kidney disease. Correction of these conditions, in turn, can lead to the development of deficiency of vitamins and other microelements. According to studies presented in the literature, nutritional status is one of the main factors determining the survival and degree of rehabilitation of patients on renal replacement therapy, as well as the effectiveness of dialysis treatment. Thus, a clinician’s knowledge of the nutritional status of this group of patients can improve their prognosis and quality of life.

The Brainbox-a tool to facilitate correlation of brain magnetic resonance imaging features to histopathology.

Magnetic resonance imaging (MRI) has limitations in identifying underlying tissue pathology, which is relevant for neurological diseases such as multiple sclerosis, stroke or brain tumours. However, there are no standardized methods for correlating MRI features with histopathology. Thus, here we aimed to develop and validate a tool that can facilitate the correlation of brain MRI features to corresponding histopathology. For this, we designed the Brainbox, a waterproof and MRI-compatible 3D printed container with an integrated 3D coordinate system. We used the Brainbox to acquire post-mortem ex vivo MRI of eight human brains, fresh and formalin-fixed, and correlated focal imaging features to histopathology using the built-in 3D coordinate system. With its built-in 3D coordinate system, the Brainbox allowed correlation of MRI features to corresponding tissue substrates. The Brainbox was used to correlate different MR image features of interest to the respective tissue substrate, including normal anatomical structures such as the hippocampus or perivascular spaces, as well as a lacunar stroke. Brain volume decreased upon fixation by 7% (P = 0.01). The Brainbox enabled degassing of specimens before scanning, reducing susceptibility artefacts and minimizing bulk motion during scanning. In conclusion, our proof-of-principle experiments demonstrate the usability of the Brainbox, which can contribute to improving the specificity of MRI and the standardization of the correlation between post-mortem ex vivo human brain MRI and histopathology. Brainboxes are available upon request from our institution.

The Effect of Secretome Hypoxia Mesenchymal Stem Cell (Sh-MSC) Therapy on PDGF and IFN-Gama Gene Expression in Male Wistar Rat Excision Models

Wounds are damage to normal anatomical structures and functions due to pathological processes that originate internally or externally and affect certain organs. The wound healing process consists of four highly integrated and overlapping hemostasis phases, inflammation, proliferation, and remodeling or network resolution. Therapy using Mesenchymal Stem Cells (MSC) is considered effective in improving skin wound healing because it has the potential for differentiation and immunoregulation and there is no potential for post-treatment rejection. This research aims to prove the influence of secretome hypoxia mesenchymal stem cells (SH-MSC) on PDGF and IF-Gamma gene expression in Wistar rats using the excision wound model. This research is in-vivo experimental research with Post-test Only Control Group Design. The research subjects were 18 male Wistar rats with excision wound models divided into three groups there are placebo gel (negative control), Clobetasol at a dose of 0.25g/kg (positive control), and the P1 group SH-MSC gel at a dose of 400 μl/kg BW, were given treatment for 5 days. On the 6th day, the skin tissue was examined using the RT-PCR method to see the expression of the PDGF and IF-gamma genes. Statistical analysis using One-way ANOVA and Post Hoc LSD test. The average PDGF gene expression in the P1 group was the highest, followed by the positive control. The lowest average expression of the PDGF gene was found in the negative control. The average IFN-γ gene expression in the negative control was the highest, followed by the positive control group. The lowest average expression of the IFN-γ gene was found in the P1 group. The administration of SH-MSCs topical gel 400μl/kg BW increased PDGF expression in male Wistar rats with excision wound models, whereas the administration of gel secretome SH-MSC at a dose of 400μl/kg BW can reduce IFN-γ levels in male Wistar rats with the excision wound model.

Development of convolutional neural network models that recognize normal anatomic structures during real-time radial-array and linear-array EUS (with videos)

EUS is a high-skill technique that requires numerous procedures to achieve competence. However, training facilities are limited worldwide. Convolutional neural network (CNN) models have been previously implemented for object detection. We developed 2 EUS-based CNN models for normal anatomic structure recognition during real-time linear- and radial-array EUS evaluations. The study was performed from February 2020 to June 2022. Consecutive patient videos of linear- and radial-array EUS videos were recorded. Expert endosonographers identified and labeled 20 normal anatomic structures within the videos for training and validation of the CNN models. Initial CNN models (CNNv1) were developed from 45 videos and the improved models (CNNv2) from an additional 102 videos. CNN model performance was compared with that of 2 expert endosonographers. CNNv1 used 45,034 linear-array EUS frames and 21,063 radial-array EUS frames. CNNv2 used 148,980 linear-array EUS frames and 128,871 radial-array EUS frames. Linear-array CNNv1 and radial-array CNNv1 achieved a 75.65% and 71.36% mean average precision (mAP) with a total loss of .19 and .18, respectively. Linear-array CNNv2 obtained an 88.7% mAP with a .06 total loss, whereas radial-array CNNv2 achieved an 83.5% mAP with a .07 total loss. CNNv2 accurately detected all studied normal anatomic structures with a >98% observed agreement during clinical validation. The proposed CNN models accurately recognize the normal anatomic structures in prerecorded videos and real-time EUS. Prospective trials are needed to evaluate the impact of these models on the learning curves of EUS trainees.

Eruptive Sebaceous Hyperplasia A rare adverse effect of systemic corticosteroid use in two immunosuppressed patients

Sebaceous hyperplasia is a benign, not uncommon cutaneous disorder. The disorder is caused by overabundance and proliferation of sebocytes in the sebaceous glands [1]. The proliferation induces enlargement of the sebaceous gland up to several times its regular size, but still keeping the normal anatomical structures. Sebacceous glands have a central duct that may become dilated in sebaceous hyperplasia due to secretion of an oily substance, sebum, which presents flesh- or yellowish coloured [2]. Sebaceous glands are localized everywhere on the skin except for palms and soles of the feet. The highest concentration of the glands is found on the face, the back, and the upper arms, which is also the most common places to encounter sebaceous hyperplasia [3]. Papules that are newly formed often swell during sweating which is pathognomonic for the disorder. Sebaceous glands are commonly associated with hair follicles, though may rarely present in hairless regions of the skin [4].

Malignant Neoplasms of the Penis with Radiologic and Pathologic Correlation.

Penile malignancy is the third most common male-specific genitourinary malignancy, with squamous cell carcinoma representing the most common histologic type. Squamous cell carcinoma is an epithelial malignancy, frequently developing from the mucosal surfaces of the foreskin, glans, and coronal sulcus and manifesting as a distal infiltrative or ulcerated mass. This typically occurs in men from the 6th to 8th decades of life, and risk factors include human papillomavirus, phimosis, presence of foreskin and poor hygiene, chronic inflammatory conditions such as lichen sclerosus, trauma, and smoking. Primary urethral malignancies including urothelial carcinoma and adenocarcinoma can occur but may lack this distal predilection. Sarcoma, melanoma, leukemia or lymphoma, and metastatic disease are less common sources of penile malignancy. Because of the sensitive nature of penile malignancies, there may be delays in seeking care and in subsequent diagnosis. Recently, the staging guidelines for penile cancer have been updated concurrently with a shift toward more penile-preserving therapies, which have led to a larger role of imaging in diagnosis, staging, and treatment planning for penile malignancies. A variety of imaging modalities may play a role in the identification and staging of penile malignancy, including an increased use of MRI for local staging of tumors, CT and PET/CT for identification of nodal and distant disease, and US for image-guided biopsy. The authors discuss an imaging approach to a spectrum of penile malignancies, with an emphasis on radiologic and pathologic correlation and how knowledge of normal tissue types and anatomic structures can aid in the diagnosis and staging of these tumors. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

The rule of five: A novel anatomical landmark for approaching cavernous sinus content.

The main objective of this study is to enhance neurosurgeons' anatomical knowledge by providing specific anatomical references of the cavernous sinus (CS). However, it is essential to clarify that our study does not seek to establish an absolute intraoperative rule due to the inherent anatomical variability that must be considered. Fifty-three cadaveric specimens were procured from the Forensic Institute (Bogotá) and subjected to dissection through an extradural approach. The measurements were taken in two distinct phases. The first phase involved the measurement of various anatomical structures in 25 specimens with respect to the anterior and posterior clinoids. The second phase, which was conducted 5 years later, involved the measurement of the distance between the foramen rotundum and the foramen ovale in 28 specimens using the L&W tools microcaliper. In 25 specimens, a perpendicular imaginary line was drawn from the lateral tip of the anterior clinoid to the floor of the medial fossa. This facilitated access to the Parkinson's triangle, which is located between the IV cranial nerve and the ophthalmic V1 nerve, revealing a constant distance of 5 mm between the lateral tip of the anterior clinoid and the IV cranial nerve. Furthermore, in 28 specimens, the mean distance from the foramen rotundum to the foramen ovale was found to be 1.3 cm bilaterally. The rule of five is a valuable tool for comprehensively understanding the anatomy of the CS, providing a reference point for the different normal anatomical structures within the CS.

Prostate Cancer and Its Mimics-A Pictorial Review.

Multiparametric prostate MRI (mpMRI) is gaining wider recommendations for diagnosing and following up on prostate cancer. However, despite the high accuracy of mpMRI, false positive and false negative results are reported. Some of these may be related to normal anatomic structures, benign lesions that may mimic cancer, or poor-quality images that hamper interpretation. The aim of this review is to discuss common potential pitfalls in the interpretation of mpMRI. mpMRI of the prostates was performed on 3T MRI scanners (Philips Achieva or Siemens Magnetom Vida) according to European Society of Urogenital Radiology (ESUR) guidelines and technical requirements. This pictorial review discusses normal anatomical structures such as the anterior fibromuscular stroma, periprostatic venous plexus, central zone, and benign conditions such as benign prostate hyperplasia (BPH), post-biopsy hemorrhage, prostatitis, and abscess that may imitate prostate cancer, as well as the appearance of prostate cancer occurring in these locations. Furthermore, suggestions on how to avoid these pitfalls are provided, and the impact of image quality is also discussed. In an era of accelerating prostate mpMRI and high demand for high-quality interpretation of the scans, radiologists should be aware of these potential pitfalls to improve their diagnostic accuracy.