Publications by authors named "Daniel R Ludwig"

Endovascular aneurysm repair requires lifelong imaging surveillance, typically with contrast-enhanced computed tomography imaging. This poses risks to patients with end-stage renal disease. Ferumoxytol, a superparamagnetic iron-based nanoparticle with minimal nephrotoxicity, has emerged as an alternative contrast agent for magnetic resonance angiography in patients with renal impairment.

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The Prostate Imaging for Recurrence Reporting (PI-RR) system was introduced in 2021 to standardize the performance and interpretation of pelvic MRI after whole-gland treatment with radical prostatectomy (RP) or radiation therapy (RT). The Prostate Imaging Reporting and Data System (PI-RADS) defines technical and reporting standards for imaging prostate cancer before treatment. Although similar imaging techniques can be applied in assessing the treated prostate gland, the interpretation varies substantially between PI-RADS and PI-RR.

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Background A recent meta-analysis showed independent associations between most Liver Imaging Reporting and Data System (LI-RADS) ancillary features (AFs) and hepatocellular carcinoma (HCC), malignancy, and benignity. However, the impact of AFs on the diagnostic performance of LI-RADS remains unclear. Purpose To evaluate the impact of applying individual AFs on the diagnostic performance of CT and MRI LI-RADS using an individual participant data (IPD) meta-analysis.

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Background The CT/MRI Liver Imaging Reporting and Data System (LI-RADS) diagnostic algorithm classifies liver observations in patients with high-risk hepatocellular carcinoma (HCC) using imaging features. However, data regarding the diagnostic performance of specific LI-RADS major feature combinations is limited. Purpose To conduct a systematic review and individual participant data (IPD) meta-analysis to establish the positive predictive values (PPVs) of LI-RADS major feature combinations using CT/MRI LI-RADS version 2018 in patients at risk for HCC.

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Purpose: The Liver Imaging Reporting and Data System (LI-RADS, LR) provides a framework for diagnosing hepatocellular carcinoma (HCC, LR-5). However, not all HCCs meet LR-5 criteria and are instead categorized as LR-M, probably or definitely malignant but not specific for HCC, necessitating biopsy for diagnosis. The purpose is to identify factors associated with HCC in LR-M observations.

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Several autoimmune diseases (primary and secondary) can affect the liver and bile ducts. While the exact cause remains unclear, early diagnosis is crucial to prevent complications. The authors' main objective is to review imaging features of various autoimmune disorders, including autoimmune hepatitis, primary biliary cholangitis, primary sclerosing cholangitis, immunoglobulin G4 (IgG4)-related diseases, and drug-induced autoimmune injury.

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Guidelines suggest the Liver Imaging Reporting and Data System (LI-RADS) may not be applicable for some populations at risk for hepatocellular carcinoma (HCC). However, data assessing the association of HCC risk factors with LI-RADS major features are lacking. To evaluate whether the association between HCC risk factors and each CT/MRI LI-RADS major feature differs among individuals at-risk for HCC.

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Biliary and peribiliary cystic lesions represent a diverse group of abnormalities, often discovered incidentally during imaging for unrelated conditions. These lesions, typically asymptomatic, necessitate precise imaging modalities to characterize their nature and determine subsequent clinical actions, such as follow-up imaging, biopsy, or surgical referral. The anatomic location of these cystic lesions, whether biliary or peribiliary, influences both diagnostic and prognostic outcomes.

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Although ultrasound is the initial imaging modality of choice in patients with right upper quadrant pain or suspected biliary obstruction, a number of challenges in clinical practice limit its utility as a stand-alone imaging modality. This article presents a focused review of gallbladder and biliary ultrasound, highlighting current knowledge gaps, emerging applications, and directions for further study. The authors cover selected topics including acute cholecystitis, cystic artery velocity, gallbladder polyps, contrast-enhanced ultrasound, and incidental biliary duct dilatation.

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Article Synopsis
  • The inferior mesenteric artery (IMA) and vein (IMV) are crucial for blood supply and drainage of the distal colon and rectum, but often overlooked in imaging due to their small size.
  • The article discusses normal and abnormal appearances of these vessels, covering various vascular issues such as aneurysms, stenosis, and potential diagnostic clues that radiologists should be aware of.
  • The authors emphasize the importance of recognizing the IMA and IMV in the context of gastrointestinal health and provide case examples to illustrate their relevance in diagnosing vascular abnormalities and collateral circulation.
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Objectives: Acute appendicitis is a common surgical condition which is usually diagnosed on CT in adult patients, though MRI is frequently used as a first-line diagnostic test in pregnant patients due to its lack of ionizing radiation and superior ability to visualize the appendix compared to ultrasound. Interpretation of abdominal MRI exams in pregnant patients with suspected appendicitis is an important skill in clinical practice, but one that is difficult to become proficient at due to its relative infrequence, even in a high-volume practice.

Methods: We created a simulation-based platform built on an online radiology viewing platform (Pacsbin) for training residents and abdominal imaging fellows to interpret pregnant appendicitis MRI exams, which we made publicly available for use by trainees at any institution (forms.

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Ischemic cholangiopathy (IC) is the leading cause of inferior long-term outcomes following donation after circulatory death (DCD) liver transplant. Biliary strictures related to IC are nonanastomotic strictures (NASs) by definition and involve the donor hepatic ducts proximal to the anastomosis, compared with postsurgical anastomotic strictures that form due to fibrotic healing. IC-related NASs can be microangiopathic with patent hepatic artery or macroangiopathic with occluded or stenotic hepatic artery.

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The radiologic diagnosis of biliary disease can be challenging due to atypical or delayed presentation, rare or less common entities, and imaging overlap of benign and malignant processes. Establishing a specific diagnosis, when possible, is important to avoid progression of infections to sepsis and multiorgan failure, and for appropriate staging and management in cases of malignancy. Gallstones are the most common biliary disease, and along with stone-related complications, including cholecystitis and choledocholithiasis, constitute the majority of acute biliary pathology.

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Hepatic ductopenia is a pathologic diagnosis characterized by a decrease in the number of intrahepatic bile ducts as a consequence of various underlying etiologies. Some etiologies, such as primary sclerosing cholangitis, primary biliary cholangitis, and ischemic cholangitis, often have distinctive imaging findings. In contrast, other causes such as chronic rejection following liver transplantation, drug-induced biliary injury, infection, malignancy such as lymphoma, and graft-versus-host disease may only have ancillary or non-specific imaging findings.

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Background & Aims: The Lemann Index (LI), an endpoint to measure cumulative structural bowel damage in Crohn's disease (CD), has been recently updated and validated. We applied this to investigate predictors of bowel damage in a real-world cohort.

Methods: We performed a retrospective study (2008-2022) involving two tertiary referral IBD centers in the US.

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Background And Aims: Perianal fistuliing 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, which seeks to unify disease severity with patient-centred goals but has not yet been validated. We aimed to apply this to a real-world cohort and to identify factors that predict transition between classes over time.

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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.

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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.

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