Abdominal Radiology最新文献

Cesarean delivery is a common procedure, currently accounting for one-third of live births in the US. In the acute post-operative setting, it can be difficult to distinguish changes of the expected recovery of the uterus from those of complications. A radiologist should be able to recognize expected postoperative findings and their evolution, such as endometrial cavity debris, small hematoma, or peri-incisional edema, when interpreting images at various stages of recovery. Commonly seen acute complications after cesarean delivery include subfascial and bladder flap hematomas, uterine dehiscence or rupture, endometritis, septic thrombophlebitis, retained products of conception, and vascular complications such as uterine artery pseudoaneurysm, arteriovenous fistula, and ovarian vein thrombosis. On the contrary, delayed complications include uterine scar niche, cesarean scar ectopic pregnancy, endometriosis, pelvic inflammatory disease, bowel obstruction, that occur beyond the post-partum period and are often manifested during subsequent pregnancies. This review aims to familiarize radiologists with the pathophysiology and timeline of the expected post-cesarean imaging findings and complications, to aid accurate diagnosis and prompt patient management.

Graphical abstract

Crohn’s disease is a transmural inflammatory bowel disease, which can progress to stricturing and internal penetrating complications. Computed tomography enterography (CTE) and magnetic resonance enterography (MRE) are utilized with endoscopy to detect and stage small bowel Crohn’s disease. Small bowel strictures and associated penetrating complications are commonly missed complications of fibrostenosing Crohn’s disease at CTE/MRE. This educational review focuses on factors contributing to unreported or overcalled strictures including disease location, postoperative anatomy, erroneous understanding of threshold dilation for stricture diagnosis, and underappreciation for how stricture diagnosis can improve patient care, emphasizing current understanding of Crohn’s small bowel strictures using illustrative cases. In addition, we explain emerging consensus for how strictures and their associated obstruction can be consistently measured and described. We also review frequently missed complications of fibrostenosing Crohn’s disease such as chronic mesenteric venous occlusion and penetrating complications, including blind-ending sinus tracts, and ileoappendiceal and complex enteroenteric fistulas. Finally, common mimics of fibrostenosing Crohn’s disease including NSAID enteropathy, radiation enteritis, and other entities are discussed, highlighting key distinguishing imaging and clinical features. Radiologists must be proactive in identifying strictures to improve patient outcomes and prevent unnecessary delay in surgical intervention or access to targeted biologic therapies.

Purpose

This study aims to assess the potential value of the non-Gaussian diffusion MRI models, including intravoxel incoherent motion (IVIM), stretched exponential model (SEM), diffusion kurtosis imaging (DKI), fractional-order calculus (FROC), and continuous-time random walk (CTRW) models, for preoperative prediction of microvascular invasion (MVI) in hepatocellular carcinoma (HCC).

Methods

A total of 61 consecutive patients were enrolled in this study. Various diffusion parameters were calculated from six diffusion models: conventional diffusion-weighted imaging (DWI) and five non-Gaussian diffusion MRI models (IVIM, SEM, DKI, FROC, and CTRW). The clinical characteristics and various diffusion parameters were analyzed using chi-square tests, independent sample t test or Mann–Whitney U test between subgroup. Logistic regression was applied to explore the risk factors from clinical variables. Diagnostic accuracy was evaluated through the area under the receiver operating characteristic (ROC) curves (AUCs), the Delong test was performed to evaluate the AUCs.

Results

Patients with MVI-positive HCC demonstrated significantly higher DKI_K (P < 0.001), FROC_β (P = 0.047 ) values, and remarkably lower CTRW_α values (P = 0.002 ). Further, multivariable logistic regression analysis indicated that DKI_K (odds ratio (OR) = 1.004, P = 0.044) and FROC_β (OR = 1.005, P = 0.027) values were significantly associated with MVI-positive HCC, with higher AUC values compared with ADC values (0.746 vs. 0.649 vs. 0.596, respectively). Additionally, the alpha-fetoprotein (AFP) levels (OR = 1.002, P = 0.009) and maximum tumor diameter (MTD) (OR = 1.001, P = 0.004) were also included as risk factors for MVI-positive HCC. Combining DKI_K and FROC_β values with the AFP levels and MTD improved the AUC value to 0.878.

Conclusions

DKI_K and FROC_β values had the potential to serve as independent predictors of MVI in HCC, and their combination with MTD and AFP levels further enhanced the performance.

Renal transplantation is an established surgical option for patients with end-stage renal failure and leads to considerable improvement in the survival and quality of life of these patients. Imaging, particularly sonography, is often used to follow-up of renal transplant patients. CT and MRI are used to further assess abnormal sonographic findings. Uncommonly, these patients present with a mass in the allograft. In this review, we discuss the causes and imaging findings of solid masses that arise in or around the renal allograft.

Purpose

Hereditary Leiomyomatosis and Renal Cell Cancer (HLRCC) is a hereditary cancer syndrome associated with germline pathogenic variants of the fumarate hydratase (FH) are at risk for the development of benign renal cysts as well as an aggressive form of renal cell carcinoma which can occur inside the cysts. This study was conducted in order to assess the role of MR imaging characteristics of HLRCC-associated cystic lesions for distinguishing benign from malignant complex renal cysts in this patient population.

Methods

This IRB-approved retrospective study included 42 HLRCC patients (mean age, 46 ± 14 years; men: women, 22:20) with a pathogenic FH germline variant with renal cysts on abdominal MRI. Between June 2002 and May 2022 these patients underwent partial or radical nephrectomy for surgical removal of 76 renal lesions suspicious for renal carcinomas. Two abdominal radiologists independently reviewed the MRI images of all lesions while blinded to the surgical pathology. The lesion characteristics, including location, 3D dimensions, internal composition, characteristics of the cyst wall, nodules, septations, enhancement patterns in different series and restricted diffusion on ADC, and b-2000 series were recorded.

Results

Out of the 76 histologically characterized renal lesions, 44 (58%) were found to be benign and 32 (42%) were malignant. Malignant cystic lesions had a significantly larger mean diameter (4.0 ± 3.4 cm) compared to benign lesions (1.8 ± 2.1 cm, p = 0.002). Inter-reader agreement analysis identified 12 imaging features with moderate agreement (κ >0.4). Univariate analysis identified 8 significant predictors of malignancy: “combined areas of enhancement on T1-weighted images during the nephrogenic phase (the nephrogenic phase, occurring approximately 70 seconds after intravenous contrast injection)”, “endophytic/exophytic mass”, “presence of a nodule”, and “nodule enhancement on T1 nephrogenic phase.” The final multivariable model for Reader 1 achieved an AUC of 0.86 and for reader 2 with an AUC of 0.91, indicating high diagnostic accuracy. At a predicted‐probability threshold of 0.17 (point = 60), the nomogram identified all malignant lesions and would have spared 57% of patients with benign cysts from unnecessary surgery.

Conclusion

Qualitative MRI features, including nodule presence, enhancement patterns, and lesion size, effectively differentiate between benign and malignant renal complex cysts in patients with HLRCC. The final multivariable model achieved high diagnostic, highlighting the potential of MRI in guiding clinical decision-making and improving management of cystic renal lesions in this high-risk population.

Graphical abstract

Created in BioRender. Sheikhy, A. (2025) https://BioRender.com/w45f229

Background

Integrating diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) measurements with existing MR imaging protocols improves the differentiation between benign and malignant adnexal lesions. We aimed to assess the additional value of quantitative ADC in diagnosing adnexal masses classified by the O-RADS-MRI score and evaluate the impact on diagnostic performance.

Methods

This retrospective cohort study analyzed 159 patients with 218 ovarian masses, classified into benign, borderline, and malignant groups via histopathological evaluation. We examined MRI parameters, including solid component size and signal intensity, time-intensity curves (TICs), ADC values and O-RADS categories. Receiver Operating Characteristic (ROC) curve analysis determined optimal ADC cut-off values for differentiating tumor classifications.

Results

The optimal cut-off values for the ADC between O-RADS MRI categories 3–4, and 4–5, were 1.36 × 10⁻³ mm²/sec and 0.99 × 10⁻³ mm²/sec respectively. the introduction of ORADS-ADC classification, utilizing these ADC cut-offs demonstrated superior diagnostic performance compared to traditional O-RADS, with improvements observed across several metrics: in ORADS-ADC 3–4 sensitivity increases from 69.2 to 94.12%, specificity from 88.4 to 98.36%, and accuracy from 76.0 to 96.84%. Similarly, in ORADS-ADC 4–5 sensitivity increases from 91.8 to 95.12%, specificity from 62.3 to 97.06%, and accuracy from 78.9 to 95.54%.

Conclusion

Incorporating DWI and ADC measurements into the O-RADS MRI classification system significantly improves ovarian tumor classification. The ORADS-ADC model markedly increases diagnostic accuracy, enhancing both sensitivity and specificity compared to traditional O-RADS, which consequently enhances clinical and therapeutic management resulting in better patient outcomes during surgical planning.

The Liver Imaging Reporting and Data System (LI-RADS) has become an essential tool for standardizing the detection, diagnosis, and treatment response assessment of hepatocellular carcinoma (HCC) using contrast-enhanced CT and MRI. With the rising incidence of HCC, the use of local–regional therapies (LRT) has also expanded. To address the increasing complexity of post-treatment imaging interpretation, the LI-RADS Treatment Response Assessment (TRA) algorithm was developed to provide a structured and reproducible approach for evaluating tumor response following various forms of LRT. However, imaging features following radiation-based therapies—such as transarterial radioembolization and stereotactic body radiation therapy—often differ from those seen after thermal ablation and transarterial chemoembolization. Recognizing these differences, the 2024 LI-RADS TRA update introduces refinements to improve diagnostic accuracy in this context. This review outlines the evolving role of LI-RADS in post-treatment assessment, highlights imaging findings associated with different LRTs, and explores ongoing refinements aimed at optimizing its clinical utility. Finally, we discuss the need for prospective validation of the new algorithm to confirm its diagnostic performance and clinical impact.

Objective

To assess the intermodality agreement between transvaginal ultrasound (TVUS) and magnetic resonance imaging (MRI) in the evaluation of deep pelvic endometriosis (DE), using a compartment-based framework that includes both classical and extended pelvic structures. This study was not designed to assess diagnostic accuracy, as no surgical or histological reference standard was used.

Methods

In this prospective study, 79 symptomatic women with clinical suspicion of DE underwent standardized TVUS and MRI protocols within a 20-day interval. Agreement was analyzed by anatomical compartment using Cohen’s Kappa coefficient. Discordant findings (TVUS-only vs. MRI-only) were quantified and tested using McNemar’s test. Detection frequencies were also compared using chi-squared tests for paired proportions. In addition to anterior and posterior compartments, we included clinically relevant structures not encompassed by standard classification models. Based on agreement and discordance patterns, each structure was categorized into a descriptive suggestion tier.

Results

Intermodality agreement varied across compartments. Almost perfect agreement was observed for the rectosigmoid (κ = 0.83), and substantial agreement for the rectum (κ = 0.65), rectovaginal septum (κ = 0.68), and ovarian endometriomas (κ ≥ 0.71). Moderate agreement was seen for the uterine serosa (κ = 0.49), vagina (κ = 0.57), bladder (κ = 0.42), and vesicouterine recess (κ = 0.54). TVUS detected significantly more lesions in key regions, including the rectosigmoid (84.8% vs. 64.6%, p = 0.006) and posterior cul-de-sac (53.2% vs. 31.6%, p = 0.010), while MRI showed relative advantages for evaluating the round ligaments and uterine serosa. An exploratory suggestion model (Fig. 1) summarizes these findings.

Conclusion

TVUS and MRI demonstrated substantial concordance across multiple pelvic compartments, particularly when interpreted by expert operators. By extending the compartment-based framework and applying a structured analysis of agreement and detection bias, this study provides insights into the complementary roles of TVUS and MRI in non-invasive DE diagnosis. In the absence of pathological confirmation, these findings should be interpreted as hypothesis-generating and not as measures of diagnostic accuracy.