Daniel Lahan-Martins

The identification of the appendix often presents a diagnostic challenge due to its significant anatomical variability, compounded by the frequency with which appendiceal pathologies manifest as atypical clinical presentations that mimic diverse abdominal and pelvic conditions. Beyond acute appendicitis, a wide spectrum of inflammatory, infiltrative, and neoplastic processes can involve the appendix, necessitating the rigorous recognition of their distinct imaging signatures. This pictorial essay reviews the normal anatomy of the appendix, its positional variations, and the spectrum of diseases that may affect it, including acute appendicitis, endometriosis, epiploic appendagitis, appendiceal diverticulitis, mucocele, and primary tumors. While computed tomography (CT) remains the gold standard for primary diagnostic evaluation, magnetic resonance imaging (MRI) serves as a critical complementary modality in specific clinical scenarios, providing superior soft-tissue characterization and improving diagnostic confidence in challenging cases. Recognition of anatomical variants and the primary mimics of the appendix is essential for the accurate interpretation of abdominal imaging studies.

Portal hypertension leads to the development of a complex and heterogeneous network of portosystemic collateral pathways, which represent adaptive responses to increased portal pressure. Although traditionally considered compensatory mechanisms, growing evidence indicates that Spontaneous Portosystemic Shunts (SPSS) are ineffective in normalizing portal pressure and may contribute to adverse clinical outcomes. In patients with cirrhosis, particularly those with preserved liver function, the presence and extent of SPSS are independently associated with hepatic encephalopathy, variceal bleeding, portal vein thrombosis, and reduced transplant-free survival, highlighting their prognostic relevance. Cross-sectional imaging with computed tomography (CT) and magnetic resonance imaging (MRI) plays a central role in the noninvasive assessment of portal hypertension by enabling comprehensive mapping of collateral circulation, including shunt size, anatomical course, and drainage pathways. These imaging characteristics are key determinants of clinical impact and therapeutic planning. This pictorial review illustrates the major portosystemic collateral pathways encountered in portal hypertension using representative clinical cases, emphasizing key imaging features and common diagnostic pitfalls, as well as highlighting the clinical significance in each context. Accurate recognition and standardized reporting of SPSS are essential to optimize risk stratification, guide management decisions, and improve outcomes in patients with portal hypertension.

Rectal anastomotic stricture (RAS) is a significant complication following rectal resection. Several techniques have been proposed for its management. However, treating complete strictures remains challenging. To describe a simple, safe, and effective technique for the treatment of complete RAS using a circular stapler under ileocolonoscopic guidance. A 43-year-old man underwent laparoscopic anterior resection of the rectum for a 7 cm serrated adenoma located 10 cm from the anal verge. The anastomosis was created 8 cm from the anal verge, and a protective loop ileostomy was fashioned. Histopathological analysis revealed a sessile serrated adenoma confined to the mucosa with foci of intramucosal carcinoma (TisN0). At 2 years postoperatively, delayed follow-up due to the COVID-19 pandemic revealed a complete RAS. Computed tomography (CT) with contrast administered through both the ileostomy efferent loop and the rectum demonstrated a short (< 1 cm) stricture at the anastomosis. The patient underwent transanal correction using a single-port system, assisted by colonoscopy through the ileostomy efferent loop. After circumferential stricturoplasty, a 31 mm circular stapler was used to perform reanastomosis under colonoscopic guidance. The patient had an uneventful recovery and was discharged on postoperative day 1. The ileostomy was closed after 45 days, and the patient presented only minimal symptoms of low anterior resection syndrome. Transanal stricturoplasty followed by circular stapler reanastomosis under endoscopic guidance appears to be a safe, simple, and effective approach for managing complete benign RAS. This technique may be considered in cases refractory to endoscopic dilation, in the place of redo surgery.

Crohn’s disease is a chronic inflammatory disorder with variable progression that often leads to hospitalization, treatment escalation, or surgery. While clinical and endoscopic indices guide disease monitoring, cross-sectional enterography provides unique visualization of transmural and extramural inflammation, offering valuable prognostic information. This systematic review and meta-analysis examined the prognostic significance of magnetic resonance enterography (MRE) and computed tomography enterography (CTE) in Crohn’s disease. Following PRISMA guidelines and a registered protocol, eight databases were systematically searched through August 2024. Two reviewers independently conducted data extraction, risk-of-bias assessment (QUADAS-2), and certainty grading (GRADE). Random-effects models were applied for pooled analyses. Eleven studies, including more than 1500 patients, met eligibility criteria. Across cohorts, transmural healing on enterography was consistently associated with favorable long-term outcomes, including a markedly lower need for surgery and hospitalization. Conversely, stenosis and persistent inflammatory activity identified patients at substantially higher risk of surgery, treatment intensification, or disease-related hospitalization. The certainty of evidence was high for surgical outcomes and moderate to low for other endpoints. Conventional enterography provides meaningful prognostic insight into Crohn’s disease and should be considered a complementary tool for risk stratification and treatment planning. Transmural healing represents a protective marker of a favorable disease course, whereas structural and inflammatory findings indicate patients who may benefit from closer monitoring or earlier therapeutic intervention.

Background: Crohn’s disease (CD) is a chronic inflammatory condition requiring regular follow-up through consultations and monitoring via laboratory, radiographic, and endoscopic examinations. Fecal calprotectin (FC) and magnetic resonance (MR) enterography are prominent non-invasive methods for assessing disease activity. However, while MR enterography is a valuable diagnostic tool, its high cost and limited accessibility present challenges for widespread use. In contrast, FC is a more affordable and accessible biomarker. To perform a systematic review (SR) examining the correlation between FC levels and MR enterography findings in patients with ileal CD. Methods: A systematic literature search was conducted across the following databases: PubMed, PubMed PMC, BVS-BIREME, SCOPUS, Web of Science, EMBASE, and Cochrane Library, and it was completed in October 2024. Results: Eight studies were included in this SR. Seven demonstrated a positive correlation between FC levels and MR enterography findings. Additionally, two studies reported significantly lower FC levels in ileal CD than in exclusive colonic or ileocolonic CD cases. The FC cutoff values ranged from >100 to >430 µg/g of feces to determine the activity of the disease. Conclusions: FC proved to be a reliable biomarker for diagnosing and monitoring CD, demonstrating a positive correlation with findings from MR enterography.

Purpose: To evaluate correlations between anthropometric tools for visceral fat assessment, including waist circumference (WC) and sagittal abdominal diameter (SAD), by computed tomography (CT)-derived visceral fat volume in patients with rectal adenocarcinoma.

This comprehensive review explores a wide range of imaging findings associated with the gallbladder (GB), from anatomic variants to rare diseases. Through an in-depth review of diagnostic modalities including ultrasound, magnetic resonance cholangiopancreatography, CT, and MRI, we aim to highlight the crucial role of imaging techniques in diagnosing GB disorders, as congenital anomalies, inflammatory diseases, neoplasms, and surgical complications. Employing a detailed analysis and comparison of imaging findings across various modalities, this review seeks to improve diagnostic accuracy for GB-related pathologies, facilitating optimal patient management. Graphical abstract

The fatty liver disease represents a complex, multifaceted challenge, requiring a multidisciplinary approach for effective management and research. This article uses conventional and advanced imaging techniques to explore the etiology, imaging patterns, and quantification methods of hepatic steatosis. Particular emphasis is placed on the challenges and advancements in the imaging diagnostics of fatty liver disease. Techniques such as ultrasound, CT, MRI, and elastography are indispensable for providing deep insights into the liver's fat content. These modalities not only distinguish between diffuse and focal steatosis but also help identify accompanying conditions, such as inflammation and fibrosis, which are critical for accurate diagnosis and management. Graphical abstract

The assessment of lymph node dimensions is a commonly used criterion in analyzing lymphatic involvement related to inflammatory or neoplastic diseases. However, it is important to understand that the interpretation of lymph nodes goes beyond simply considering their size. A pathologic lymph node can present with enlarged dimensions, a heterogeneous appearance, increased cortex thickness, irregular contours, or a lobulated shape. In this context, it is essential to consider not only the dimensions but also the morphology, attenuation, and enhancement of lymph nodes on imaging exams. This article aims to demonstrate how characteristics of lymph nodes, beyond their size, can provide crucial insights that assist in diagnostic reasoning, focusing on computed tomography. By emphasizing different enhancement patterns, attenuation, and the potential contents related to these patterns, the study seeks to show how these features can indicate possible differential diagnoses and guide more accurate clinical assessments. Graphical abstract

Several studies have demonstrated statistical and texture analysis abilities to differentiate cancerous from healthy tissue in magnetic resonance imaging. This study developed a method based on texture analysis and machine learning to differentiate prostate findings. Forty-eight male patients with PI-RADS classification and subsequent radical prostatectomy histopathological analysis were used as gold standard. Experienced radiologists delimited the regions of interest in magnetic resonance images. Six different groups of images were used to perform multiple analyses (seven analyses variations). Those analyses were outlined by specialists in urology as those of most significant importance for the classification. Forty texture features were extracted from each image and processed with Random Forest, Support Vector Machine, K-Nearest Neighbors, and Naive Bayes. Those seven analyses variation results were described in terms of area under the ROC curve (AUC), accuracy, F-score, precision and sensitivity. The highest AUC (93.7%) and accuracy (88.8%) were obtained when differentiating the group with both MRI and histopathology positive findings against the group with both negative MRI and histopathology. When differentiating the group with both MRI and histopathology positive findings versus the peripheral image zone group the AUC value was 86.6%. When differentiating the group with negative MRI/positive histopathology versus the group with both negative MRI and histopathology the AUC value was 80.7%. The evaluation of statistical and texture analysis promoted very suggestive indications for future work in prostate cancer suspicious regions. The method is fast for both region of interest selection and classification with machine learning and the result brings original contributions in the classification of different groups of patients. This tool is low-cost, and can be used to assist diagnostic decisions.