Intraprocedural Versus Initial Follow-up Minimal Ablative Margin Assessment After Colorectal Liver Metastasis Thermal Ablation: Which One Better Predicts Local Outcomes?

OBJECTIVES: The aim of this study was to investigate the prognostic value of 3-dimensional minimal ablative margin (MAM) quantified by intraprocedural versus initial follow-up computed tomography (CT) in predicting local tumor progression (LTP) after colorectal liver metastasis (CLM) thermal ablation. MATERIALS AND METHODS: This single-institution, patient-clustered, tumor-based retrospective study included patients undergoing microwave and radiofrequency ablation between 2016 and 2021. Patients without intraprocedural and initial follow-up contrast-enhanced CT, residual tumors, or with follow-up less than 1 year without LTP were excluded. Minimal ablative margin was quantified by a biomechanical deformable image registration method with segmentations of CLMs on intraprocedural preablation CT and ablation zones on intraprocedural postablation and initial follow-up CT. Prognostic value of MAM to predict LTP was tested using area under the curve and competing-risk regression model. RESULTS: A total of 68 patients (mean age ± standard deviation, 57 ± 12 years; 43 men) with 133 CLMs were included. During a median follow-up of 30.3 months, LTP rate was 17% (22/133). The median volume of ablation zone was 27 mL and 16 mL segmented on intraprocedural and initial follow-up CT, respectively ( P < 0.001), with corresponding median MAM of 4.7 mm and 0 mm, respectively ( P < 0.001). The area under the curve was higher for MAM quantified on intraprocedural CT (0.89; 95% confidence interval [CI], 0.83-0.94) compared with initial follow-up CT (0.66; 95% CI, 0.54-0.76) in predicting 1-year LTP ( P < 0.001). An MAM of 0 mm on intraprocedural CT was an independent predictor of LTP with a subdistribution hazards ratio of 11.9 (95% CI, 4.9-28.9; P < 0.001), compared with 2.4 (95% CI, 0.9-6.0; P = 0.07) on initial follow-up CT. CONCLUSIONS: Ablative margin quantified on intraprocedural CT significantly outperformed initial follow-up CT in predicting LTP and should be used for ablation endpoint assessment.

Pitfall of 18 F-PSMA PyL PET/CT Imaging of a Displaced Urinary Bladder as Recurrent Prostate Malignancy.

ABSTRACT: We herein present a potential pitfall in the setting of restaging PSMA PyL PET/CT. In this case, there is large non-PSMA-avid cystic structure in the mid pelvis, probably representing a postprostatectomy lymphocele, which was mistaken for the urinary bladder, resulting in the displaced and somewhat crescentic urinary bladder to be deemed recurrence. Subsequently, biopsy and retrospective review of images confirms displaced urinary bladder containing physiologic excreted activity.

Is fluoroscopy-guided percutaneous bone biopsy of diabetic foot with suspected osteomyelitis worthwhile? A retrospective study.

BACKGROUND: Diabetic foot infection, particularly osteomyelitis, is a major risk factor of amputation in persons with diabetes. Bone biopsy with microbial examination is considered the gold standard of diagnosis of osteomyelitis, providing information about the offending pathogens as well as their antibiotics susceptibility. This allows targeting of these pathogens with narrow spectrum antibiotics, potentially reducing emergence of antimicrobial resistance. Percutaneous fluoroscopy guided bone biopsy allows accurate and safe targeting of the affected bone. METHODS: In a single tertiary medical institution and over 9 year period, we performed 170 percutaneous bone biopsies. We retrosepctively reviewed the medical record of these patients including patients' demographics, imaging and biopsy microbiology and pathollogic results. RESULTS: Microbiological cultures of 80 samples (47.1%) were positive with 53.8% of the positive culture showed monomicrobial growth and the remaining were polymicrobial. Of the positive bone samples 71.3% grew Gram-positive bacteria. Staphylococcus aureus was the most frequently isolated pathogen from positive bone cultures with almost one third showing methicillin resistence. Enterococcus species were the most frequently isolated pathogens from polymicrobial samples. Enterobacteriaceae species were the most common Gram-negative pathogens and were more common in polymicrobial samples. CONCLUSIONS: Percutaneous image-guided bone biopsy is a low-risk, minimally invasive procedure that can provide valuable information about microbial pathogens and therefore enable targeting these pathogens with narrow spectrum antibiotics.

Clinicopathological features of incidental parotid lesions.

BACKGROUND: The purpose of this study is to determine the histopathological spectrum and risk of primary malignancy of asymptomatic parotid lesions incidentally discovered on cross-sectional imaging. METHODS: Over a 10-year period, 154 patients underwent 163 ultrasound-guided parotid lesion biopsies at our institution. This retrospective chart review included 89 lesions in 87 patients with asymptomatic parotid lesions discovered on cross-sectional imaging studies performed for unrelated clinical indications. The histopathologic findings of all sampled lesions were reviewed. We evaluated the patient demographics and pathological diagnoses of sampled parotid lesions to determine the histopathological spectrum and risk of malignancy. RESULTS: The average age was 67.5 years and 92 % were males. 25 % of patients had bilateral lesions. The average size of the parotid lesions was 1.5 cm and 91 % were located in the superficial lobe. 92.1 % of lesions were benign with Warthin tumor being the most common diagnosis followed by pleomorphic adenoma. 2.3 % of lesions were primary parotid malignant neoplasms, while 5.6 % were metastatic lesions in patients with known malignancy. CONCLUSIONS: The incidence of primary parotid malignant neoplasm in asymptomatic incidentally discovered parotid lesions is low. Imaging or clinical follow-up may be considered in patients with incidental parotid lesions who prefer to avoid biopsy.

Cystic Artery Hemorrhage after Cholecystostomy Catheter Exchange Treated with Transcatheter Embolization.

The pathogenesis of formation of cystic artery pseudoaneurysms is not well understood, but is thought to result from erosion of the cystic artery wall from the adjacent inflammatory process associated with acute or chronic cholecystitis. The presented case discusses an incident of hemorrhage from a cystic artery pseudoaneurysm resulting in a large perihepatic hematoma as well as hemobilia, which developed after a routine cholecystostomy catheter exchange. This was treated with transcatheter embolization using ethylene-vinyl alcohol copolymer.

The thyroid: review of imaging features and biopsy techniques with radiologic-pathologic correlation.

Knowledge of the normal and abnormal imaging appearances of the thyroid gland is essential for appropriate identification and diagnosis of thyroid lesions. Thyroid nodules are often detected incidentally at computed tomography, magnetic resonance imaging, and positron emission tomography; however, ultrasonography (US) is the most commonly used imaging modality for characterization of these nodules. US characteristics that increase the likelihood of malignancy in a thyroid nodule include microcalcifications, solid composition, and central vascularity. Nuclear scintigraphy is commonly used for evaluation of physiologic thyroid function and for identification of metabolically active and inactive nodules. When fine-needle aspiration biopsy (FNAB) of a lesion is indicated based on clinical and radiologic features, appropriate US-guided biopsy technique and careful cytologic analysis are crucial for making the diagnosis. FNAB and core biopsy are the two percutaneous techniques used to obtain a specimen, with the latter technique being indicated following nondiagnostic or indeterminate FNAB. Specimen adequacy and diagnostic accuracy vary due to several factors, including location of aspiration and biopsy technique used. The radiologist must have a basic knowledge of thyroid disease, be familiar with specimen processing, and recognize the cytologic and radiologic appearances of thyroid lesions, all of which will facilitate the management of these lesions. Online supplemental material is available for this article.

MRI of suspected lower extremity musculoskeletal infection in the pediatric patient: how useful is bilateral imaging?

OBJECTIVE: The purpose of this study was to determine the frequency of bilateral abnormalities in children with suspected lower extremity musculoskeletal infection and the impact of detection of contralateral abnormalities by MRI on patient management. MATERIALS AND METHODS: A retrospective review of 165 consecutive bilateral lower extremity MRI examinations performed for suspected musculoskeletal infection in pediatric patients (64% boys and 36% girls; mean age, 7.5 years; age range, 0-18 years) in 2010 at a children's hospital was performed. Imaging findings were compared with the final clinical diagnosis and management. RESULTS: The MRI examination was normal in 2% (4/165). Osteomyelitis was diagnosed in 33% (54/165) of the MRI examinations; among these examinations 20% (11/54) had both ipsilateral septic arthritis and osteomyelitis, 2% (1/54) had bilateral osteomyelitis, and 67% (111/165) of the examinations were negative for osteomyelitis. Bilateral abnormalities were detected in 20% (22/111) of patients without osteomyelitis, with 18% (4/22) presenting with bilateral signs or symptoms. Abnormalities in the contralateral extremity included myositis (18%, 4/22), stress reaction (18%, 4/22), subcutaneous edema (18%, 4/22), leukemia (14%, 3/22), reactive joint effusion (14%, 3/22), Baker cyst (5%, 1/22), and osteonecrosis (5%, 1/22). Identification of clinically unsuspected abnormalities of the contralateral extremity by MRI was not associated with alterations in medical or surgical management in children with or without osteomyelitis. CONCLUSION: Clinically unsuspected abnormalities of the asymptomatic contralateral lower extremity are common in children referred for MRI of suspected musculoskeletal infection. However, detection of these abnormalities is not associated with alterations in patient management.

Imaging features of intravesical urachal cysts in children.

BACKGROUND: Urachal cysts, part of the spectrum of congenital urachal anomalies, are typically extrinsic to the urinary bladder. OBJECTIVE: The purpose of this study is to present the salient imaging features of a pediatric series of unusual intravesical urachal cysts that protrude into the bladder lumen. MATERIALS AND METHODS: Five children with intravesical urachal cysts depicted on imaging studies were retrospectively identified during a 6-year period at a children's hospital. The clinical charts and findings on ultrasound (US) and voiding cystourethrogram (VCUG) were reviewed. RESULTS: In all five children, US revealed a thin-walled ovoid cystic structure containing anechoic fluid or echogenic debris and residing along the midline of the anterosuperior aspect of the urinary bladder protruding into the bladder lumen. Histological examination of the partial cystectomy specimen from one child revealed a cystic urachal remnant with intestinal mucosal lining and reactive lymphoid hyperplasia. The cysts in the four other children were managed conservatively without operative intervention. CONCLUSION: The purpose of this report is to expand the spectrum of urachal remnant anomalies to include these newly recognized intravesical urachal cysts, which are characterized on US by the presence of a thin-walled cyst along the midline anterosuperior aspect of the urinary bladder.