Evaluating the Change in 18F-Fluorodeoxyglucose Uptake in Perianal Fistulas on PET/CT over Time: A Serial Retrospective Analysis.

RATIONALE AND OBJECTIVES: Perianal fistulas on18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) can be an incidental site of FDG uptake in patients undergoing PET for other indications. There are no longitudinal studies describing FDG uptake patterns in perianal fistulas. Therefore, we aimed to analyze changes in FDG uptake over time in patients with incidental perianal fistulas. PATIENTS AND METHODS: Patients who underwent at least two FDG-PET/CTs between January 2011 and May 2023, with incidental perianal fistula, were retrospectively identified. We analyzed all sequential PET/CTs to determine the presence of a perianal fistula and recorded the fistula's maximum standardized uptake value (SUVmax). Statistical analysis compared fistula FDG-avidity in the initial versus final PET/CT examinations and assessed the correlation between initial fistula SUVmax and percent change over time. RESULTS: The study included 15 fistulas in 14 patients, with an average of 5 PET/CT examinations per patient. The average interval between the first and last PET/CT was 24 months (range: 6-64). The average initial fistula SUVmax (11.28 ± 3.81) was significantly higher than the final fistula SUVmax (7.22 ± 3.99) (p = 0.0067). The fistula SUVmax declined by an average of 32.01 ± 35.33% with no significant correlation between initial fistula SUVmax and percent change over time (r = -0.213, p = 0.443, 95% CI -0.66-0.35). CONCLUSION: FDG uptake in perianal fistulas shows temporal fluctuations but follows a decreasing SUVmax trend, possibly indicating a relationship with inflammatory activity. Further studies with larger cohorts paired with perianal fistula pelvic MR imaging are needed to validate these observations and their utility in guiding further management.

TOpCLASS Expert Consensus Classification of Perianal Fistulizing Crohn's Disease: A Real-World Application in a Serial Fistula MRI Cohort.

BACKGROUND AND AIMS: Perianal fistulizing Crohn's disease (PFCD) is an aggressive phenotype of Crohn's disease defined by frequent relapses and disabling symptoms. A novel consensus classification system was recently outlined by the TOpCLASS consortium that seeks to unify disease severity with patient-centered goals but has not yet been validated. We aimed to apply this to a real-world cohort and identify factors that predict transition between classes over time. METHODS: We identified all patients with PFCD and at least one baseline and one follow-up pelvic (pMRI). TOpCLASS classification, disease characteristics, and imaging indices were collected retrospectively at time periods corresponding with respective MRIs. RESULTS: We identified 100 patients with PFCD of which 96 were assigned TOpCLASS Classes 1 - 2c at baseline. Most patients (78.1%) started in Class 2b, but changes in classification were observed in 52.1% of all patients. Male sex (72.0%, 46.6%, 40.0%, p = 0.03) and prior perianal surgery (52.0% vs 44.6% vs 40.0%, p = 0.02) were more frequently observed in those with improved class. Baseline pMRI indices were not associated with changes in classification, however, greater improvements in mVAI, MODIFI-CD, and PEMPAC were seen among those who improved. Linear mixed effect modeling identified only male sex (-0.31, 95% CI -0.60 to -0.02) with improvement in class. CONCLUSION: The TOpCLASS classification highlights the dynamic nature of PFCD over time, however, our ability to predict transitions between classes remains limited and requires prospective assessment. Improvement in MRI index scores over time was associated with a transition to lower TOpCLASS classification.

Inflammatory and Malignant Uptake Along Crohn Perianal Fistula on 18 F-FDG.

ABSTRACT: Inflammatory increased metabolic activity was discovered in the left anal canal on an 18 F-FDG PET/CT scan performed for initial staging of anal squamous cell carcinoma in a patient with history of perianal Crohn disease. This increased uptake was due to a complex intersphincteric perianal fistula with supralevator extension, with a secondary, contiguous, superficial focus of squamous cell carcinoma at the anal verge that was identified on an MRI performed on the same day.

Geldof Expert Consensus Classification of Perianal Fistulizing Crohn's Disease: A Real-World Application in a Serial Fistula MRI Cohort.

Background and Aims: Perianal fistulizing Crohn's disease (CD-PAF) is an aggressive phenotype of Crohn's disease (CD) defined by frequent relapses and disabling symptoms. A novel consensus classification system was recently outlined by Geldof et al. that seeks to unify disease severity with patient-centered goals but has not yet been validated. We aimed to apply this to a real-world cohort and identify factors that predict transition between classes over time. Methods: We identified all patients with CD-PAF and at least one baseline and one follow-up pelvic (pMRI). Geldof Classification, disease characteristics, and imaging indices were collected retrospectively at time periods corresponding with respective MRIs. Results: We identified 100 patients with CD-PAF of which 96 were assigned Geldof Classes 1 - 2c at baseline. Most patients (78.1%) started in Class 2b, but changes in classification were observed in 52.1% of all patients. Male sex (72.0%, 46.6%, 40.0%, p = 0.03) and prior perianal surgery (52.0% vs 44.6% vs 40.0%, p = 0.02) were more frequently observed in those with improved. Baseline pMRI indices were not associated with changes in classification, however, greater improvements in mVAI, MODIFI-CD, and PEMPAC were seen among those who improved. Linear mixed effect modeling identified only male sex (-0.31, 95% CI -0.60 to -0.02) with improvement in class. Conclusion: Geldof classification highlights the dynamic nature of CD-PAF over time, however, our ability to predict transitions between classes remains limited and requires prospective assessment. Improvement in MRI index scores over time was associated with a transition to lower Geldof classification.

Perianal fistulizing Crohn's disease: Current perspectives on diagnosis, monitoring and management with a focus on emerging therapies.

Crohn's disease (CD), a chronic inflammatory bowel disorder, manifests in various phenotypes, with fistulizing perianal CD (CD-PAF) being one of its most severe phenotypes. Characterized by fistula formation and abscesses, CD-PAF impacts 17% to 34% of all CD cases and with a significantly deleterious impact on patient's quality of life, while increasing the risk for anorectal cancers. The pathogenesis involves a complex interplay of genetic, immunological and environmental factors, with cytokines such as tumor necrosis factor-alpha (TNF-α) and transforming growth factor-beta (TGF-ß) playing pivotal roles. Diagnostic protocols require a multi-disciplinary approach including colonoscopy, examination under anesthesia and magnetic resonance imaging. In terms of treatment, biologics alone often prove inadequate, making surgical interventions such as setons and fistula surgeries essential. Emerging therapies such as mesenchymal stem cells are under study. The South Asian context adds layers of complexity, including diagnostic ambiguities related to high tuberculosis prevalence, healthcare access limitations and cultural stigma toward perianal Crohn's disease and ostomy surgery. Effective management necessitates an integrated, multi-disciplinary approach, especially in resource-constrained settings. Despite advances, there remain significant gaps in understanding the disease's pathophysiology and a dearth of standardized outcome measures, underscoring the urgent need for comprehensive research.

Quantifying 18F-Fluorodeoxyglucose Uptake in Perianal Fistulas on PET/CT: A Retrospective Analysis.

RATIONALE AND OBJECTIVES: The use of 18F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT) in assessing inflammatory diseases has shown significant promise. Uptake patterns in perianal fistulas, which may be an incidental finding on PET/CT, have not been purposefully studied. Our aim was to compare FDG uptake of perianal fistulas to that of the liver and anal canal in patients who underwent PET/CT for hematologic/oncologic diagnosis or staging. MATERIALS AND METHODS: We retrospectively identified patients who underwent FDG-PET/CT imaging between January 2011 and May 2023, where the report described a perianal fistula or abscess. PET/CTs of patients included in the study were retrospectively analyzed to record the maximum standardized uptake value (SUVmax) of the fistula, abscess, anal canal, rectum, and liver. Fistula-to-liver and Fistula-to-anus SUVmax ratios were calculated. We statistically compared FDG activity among the fistula, liver, and anal canal. We also assessed FDG activity in patients with vs. without anorectal cancer, as well as across different St. James fistula grades. RESULTS: The study included 24 patients with identifiable fistulas. Fistula SUVmax (mean=10.8 ± 5.28) was significantly higher than both the liver (mean=3.09 ± 0.584, p < 0.0001) and the anal canal (mean=5.98 ± 2.63, p = 0.0005). Abscess fistula SUVmax was 15.8 ± 4.91. St. James grade 1 fistulas had significantly lower SUVmax compared to grades 2 and 4 (p = 0.0224 and p = 0.0295, respectively). No significant differences existed in SUVmax ratios between anorectal and non-anorectal cancer groups. CONCLUSION: Perianal fistulas have increased FDG avidity with fistula SUVmax values that are significantly higher than the anal canal.

Metastatic Renal Cell Carcinoma in a Patient With Autosomal Dominant Polycystic Kidney Disease.

ABSTRACT: Autosomal dominant polycystic kidney disease (ADPKD) manifests as multiple cysts in the kidneys and liver but can also present with musculoskeletal and cardiovascular abnormalities. ADPKD patients are at increased risk for renal cell carcinoma development. We show the FDG PET/CT findings in a patient with renal cell carcinoma secondary to ADPKD and complicated by worsening pulmonary metastasis. The primary renal tumor shows intense FDG uptake despite no suspicious features with contrast CT.

Female-specific pancreatic cancer survival from CT imaging of visceral fat implicates glutathione metabolism in solid tumors.

RATIONALE AND OBJECTIVES: To identify if body composition, assessed with preoperative CT-based visceral fat ratio quantification as well as tumor metabolic gene expression, predicts sex-dependent overall survival (OS) in patients with pancreatic ductal adenocarcinoma (PDAC). MATERIALS AND METHODS: This was a retrospective analysis of preoperative CT in 98 male and 107 female patients with PDAC. Relative visceral fat (rVFA; visceral fat normalized to total fat) was measured automatically using software and corrected manually. Median and optimized rVFA thresholds were determined according to published methods. Kaplan Meier and log-rank tests were used to estimate OS. Multivariate models were developed to identify interactions between sex, rVFA, and OS. Unsupervised gene expression analysis of PDAC tumors from The Cancer Genome Atlas (TCGA) was performed to identify metabolic pathways with similar survival patterns to rVFA. RESULTS: Optimized preoperative rVFA threshold of 38.9% predicted significantly different OS in females with a median OS of 15 months (above threshold) vs 24 months (below threshold; p = 0.004). No significant threshold was identified in males. This female-specific significance was independent of age, stage, and presence of chronic pancreatitis (p = 0.02). Tumor gene expression analysis identified female-specific stratification from a five-gene signature of glutathione S-transferases. This was observed for PDAC as well as clear cell renal carcinoma and glioblastoma. CONCLUSION: CT-based assessments of visceral fat can predict pancreatic cancer OS in females. Glutathione S-transferase expression in tumors predicts female-specific OS in a similar fashion.

Clinical situations for which 3D Printing is considered an appropriate representation or extension of data contained in a medical imaging examination: vascular conditions.

BACKGROUND: Medical three-dimensional (3D) printing has demonstrated utility and value in anatomic models for vascular conditions. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (3DPSIG) provides appropriateness recommendations for vascular 3D printing indications. METHODS: A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with vascular indications. Each study was vetted by the authors and strength of evidence was assessed according to published appropriateness ratings. RESULTS: Evidence-based recommendations for when 3D printing is appropriate are provided for the following areas: aneurysm, dissection, extremity vascular disease, other arterial diseases, acute venous thromboembolic disease, venous disorders, lymphedema, congenital vascular malformations, vascular trauma, vascular tumors, visceral vasculature for surgical planning, dialysis access, vascular research/development and modeling, and other vasculopathy. Recommendations are provided in accordance with strength of evidence of publications corresponding to each vascular condition combined with expert opinion from members of the 3DPSIG. CONCLUSION: This consensus appropriateness ratings document, created by the members of the 3DPSIG, provides an updated reference for clinical standards of 3D printing for the care of patients with vascular conditions.

Reverse Engineering and 3D Printing of Medical Devices for Drug Delivery and Drug-Embedded Anatomic Implants.

In recent years, 3D printing (3DP) has advanced traditional medical treatments. This review explores the fusion of reverse engineering and 3D printing of medical implants, with a specific focus on drug delivery applications. The potential for 3D printing technology to create patient-specific implants and intricate anatomical models is discussed, along with its ability to address challenges in medical treatment. The article summarizes the current landscape, challenges, benefits, and emerging trends of using 3D-printed formulations for medical implantation and drug delivery purposes.

Clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: neurosurgical and otolaryngologic conditions.

BACKGROUND: Medical three dimensional (3D) printing is performed for neurosurgical and otolaryngologic conditions, but without evidence-based guidance on clinical appropriateness. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides appropriateness recommendations for neurologic 3D printing conditions. METHODS: A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with neurologic and otolaryngologic conditions. Each study was vetted by the authors and strength of evidence was assessed according to published guidelines. RESULTS: Evidence-based recommendations for when 3D printing is appropriate are provided for diseases of the calvaria and skull base, brain tumors and cerebrovascular disease. Recommendations are provided in accordance with strength of evidence of publications corresponding to each neurologic condition combined with expert opinion from members of the 3D printing SIG. CONCLUSIONS: This consensus guidance document, created by the members of the 3D printing SIG, provides a reference for clinical standards of 3D printing for neurologic conditions.

Preoperative computed tomography in Fournier's gangrene does not delay time to surgery.

PURPOSE: Fournier's gangrene (FG), a rapidly progressive necrotizing soft tissue infection of the external genitalia and perineum, necessitates urgent surgical debridement. The time to surgery effect of preoperative computed tomography (CT) in managing this condition is yet to be fully explored. The purpose of this study was to assess whether obtaining a preoperative CT in patients with FG impacts the time to surgical intervention. METHODS: This was a single-center retrospective study of patients who underwent CT prior to surgical debridement of FG during a 9-year period vs patients who did not undergo CT. In 76 patients (male = 39, mean age = 51.8), 38 patients with FG received a preoperative CT, and 38 patients with FG did not receive CT prior to surgical debridement. Time to operating room and outcome metrics were compared between CT and non-CT groups. RESULTS: The time from hospital presentation to surgical intervention was not significantly different between patients who underwent CT and those who did not (6.65 ± 3.71 vs 5.73 ± 4.33 h, p = 0.37). There were also no significant differences in cost ($130,000 ± $102,000 vs $142,000 ± $152,000, p = 0.37), mortality (8 vs 7, p = 1), duration of hospital stay (15.5 ± 15 vs 15.7 ± 11.6 days, p = 0.95), average intensive care unit stay (5.82 ± 5.38 days vs 6.97 ± 8.58 days, p = 0.48), and APACHE score (12 ± 4.65 vs 13.9 ± 5.6, p =0.12). CONCLUSION: Obtaining a preoperative CT did not delay surgical intervention in patients with FG.

Computed Tomography Attenuation of Three-Dimensional (3D) Printing Materials-Depository to Aid in Constructing 3D-Printed Phantoms.

Three-dimensionally printed phantoms are increasingly used in medical imaging and research due to their cost-effectiveness and customizability, offering valuable alternatives to commercial phantoms. The purpose of this study was to assess the computed tomography (CT) attenuation characteristics of 27 resin materials from Formlabs, a 3D printing equipment and materials manufacturer. Cube phantoms (both solid and hollow constructions) produced with each resin were subjected to CT scanning under varying tube current-time products with attenuation measurements recorded in Hounsfield units (HU). The resins exhibited a wide range of attenuation values (-3.33 to 2666.27 HU), closely mimicking a range of human tissues, from fluids to dense bone structures. The resins also demonstrated consistent attenuation regardless of changes in the tube current. The CT attenuation analysis of FormLabs resins produced an archive of radiological imaging characteristics of photopolymers that can be utilized to construct more accurate tissue mimicking medical phantoms and improve the evaluation of imaging device performance.

A New (Digital) Era in Medical Journalism: Leveraging Social Media and Other Online Tools to Increase Reach and Engagement.

Social media is a popular communication and marketing tool in modern society, with the power to reach and engage large audiences. Many members of the medical and radiology communities have embraced social media platforms, particularly X (formerly known as Twitter), as an efficient and economic means for performing patient outreach, disseminating research and educational materials, building networks, and promoting diversity. Editors of medical journals with a clear vision and relevant expertise can leverage social media and other digital tools to advance the journal's mission, further their interests, and directly benefit journal authors and readers. For editors, social media offers a means to increase article visibility and downloads, expand awareness of volunteer opportunities, and use metrics and other feedback to inform future initiatives. Authors benefit from broader dissemination of their work, which aids establishment of a national or international reputation. Readers can receive high-quality high-yield content in a digestible format directly on their devices while actively engaging with journal editors and authors in the online community. The authors highlight the multifaceted benefits of social media engagement and digital tool implementation in the context of medical journalism and summarize the activities of the RadioGraphics Social Media and Digital Innovation Team. By enumerating the social media activities of RadioGraphics and describing the underlying rationale for each activity, the authors present a blueprint for other medical journals considering similar initiatives. ©RSNA, 2023.

Visualizing the malperfusion effect of coronary occlusion as a sequela of limited type A aortic dissection.

Limited type A aortic dissection (LTAAD) is a rare subtype of dissection that is confined within a well-defined border of the ascending aorta. These dissections may occur in the remaining native portion of the aortic root following aortic root replacement and can be complicated by malperfusion syndrome-a syndrome where dissections compromise the aortic branches and lead to end-organ ischemia. Because LTAAD is confined within the ascending aorta, malperfusion syndrome may preferentially affect the coronary arteries resulting in coronary malperfusion, myocardial infarction, and increased mortality. We report a case of LTAAD and malperfusion syndrome of the left main coronary artery which resulted in inadequate contrast opacification of the aorta and failure of the dissection protocol to trigger on computed tomography (CT). Upon further evaluation of the situation, the radiologist oversaw the manual triggering of CT acquisitions which yielded an actionable CT at 6 minutes post-contrast and real-time visualization of the patient's developing cardiac ischemia.

Perineal hernia as a sequela of anal reconstruction surgeries in perianal Crohn's disease.

Perineal hernia is a rare complication of pelvic surgeries that can occur in patients with perianal Crohn's disease (pCD) as a long-term outcome of surgeries for complex fistula treatment. We present a case of a symptomatic pCD male patient with multiple perianal surgeries who presents with anal pain, diarrhea, and discharge. Magnetic resonance imaging showed a perineal hernia in the ischioanal fossa violating the convergence of the left external sphincter complex. The hernia was treated with an open primary hernia repair via the perineal approach. It recurred after 3 months, and the patient underwent secondary hernia repair with gracilis muscle interposition and mesh placement. Unfortunately, this was complicated by superficial skin dehiscence and mesh extrusion, but the flap remained viable and the hernia repair was intact. Incidence, symptoms, risk factors, imaging findings, and management of perineal hernias are reviewed.