Effects of patient-specific treatment planning on eligibility for photodynamic therapy of deep tissue abscess cavities: retrospective Monte Carlo simulation study.

SIGNIFICANCE: Antimicrobial photodynamic therapy (PDT) effectively kills bacterial strains found in deep tissue abscess cavities. PDT response hinges on multiple factors, including light dose, which depends on patient optical properties. AIM: Computed tomography images for 60 abscess drainage subjects were segmented and used for Monte Carlo (MC) simulation. We evaluated effects of optical properties and abscess morphology on PDT eligibility and generated treatment plans. APPROACH: A range of abscess wall absorptions (µa , wall) and intra-cavity Intralipid concentrations were simulated. At each combination, the threshold optical power and optimal Intralipid concentration were found for a fluence rate target, with subjects being eligible for PDT if the target was attainable with <2000 mW of source light. Further simulations were performed with absorption within the cavity (µa , cavity). RESULTS: Patient-specific treatment planning substantially increased the number of subjects expected to achieve an efficacious light dose for antimicrobial PDT, especially with Intralipid modification. The threshold optical power and optimal Intralipid concentration increased with increasing µa , wall (p < 0.001). PDT eligibility improved with patient-specific treatment planning (p < 0.0001). With µa , wall = 0.2 cm - 1, eligibility increased from 42% to 92%. Increasing µa , cavity reduced PDT eligibility (p < 0.0001); modifying the delivered optical power had the greatest impact in this case. CONCLUSIONS: MC-based treatment planning greatly increases eligibility for PDT of abscess cavities.

Photodynamic therapy of deep tissue abscess cavities: Retrospective image-based feasibility study using Monte Carlo simulation.

PURPOSE: Deep tissue abscesses remain a serious cause of morbidity, mortality, and hospital stay despite development of percutaneous drainage and increasing use of perioperative antibiotics. The goal of this study was to examine the feasibility of methylene blue (MB) mediated photodynamic therapy (PDT) for treatment of infected abscesses with intracavity MB delivery, using computed tomography (CT) imaging data from a representative abscess patient population and Monte Carlo simulation of light delivery. METHODS: This retrospective study included all adult subjects that received percutaneous abscess drainage between 1 January 2014 and 31 December 2014 at our institution whose abscess was confirmed by abdominal CT imaging less than 1 week preprocedure (n = 358). Of these, 40 subjects were further analyzed with Monte Carlo simulation. Abscess volumes were segmented from CT images, and imported into the Monte Carlo simulation space. Monte Carlo simulations were performed with a single fiber placement for each abscess, with the optical power at which a fluence rate of either 4 or 20 mW/cm2 was achieved for 95% of the abscess wall recorded. Subjects for which a fluence rate of 4 mW/cm2 was attainable in 95% of the abscess wall with a maximum input optical power of 2000 mW were considered eligible for MB-PDT. RESULTS: 42.5% of subjects would have been eligible for MB-PDT, with 17.5% attaining the higher threshold of 20 mW/cm2 in 95% of the abscess wall, given a 1% Intralipid concentration within the abscess cavity and the assumed abscess wall optical properties. The mean optical power necessary was 680 ± 580 mW for the 4 mW/cm2 threshold, and 1100 ± 600 mW for the 20 mW/cm2 threshold. Abscess surface area and threshold optical power were correlated (Spearman ρ = 0.73, P = 0.001), with larger abscesses requiring higher optical power. Of the subjects who were not eligible for MB-PDT, abscess volumes (150 ± 120 vs 62 ± 41 cm3 , P = 0.0049) and surface areas (320 ± 200 vs 140 ± 70 cm2 , P = 0.0015) tended to be larger than for those who were eligible. There were no significant differences in eligibility, optical power required, or abscess volume or surface area based on abscess location. For all eligible subjects, at the optical power necessary to achieve 4 mW/cm2 in 95% of the abscess wall, 2.5 ± 3.7% (0%-13.2%) of the wall experienced a fluence rate greater than or equal to 400 mW/cm2 . At the 20 mW/cm2 threshold, 8.8 ± 11.4% (0%-31.1%) of the wall surpassed this 400 mW/cm2 level. If subjects with greater than 5% of the wall exceeding 400 mW/cm2 are treated as ineligible, overall eligibility becomes 32.5% for the 4 mW/cm2 threshold and 10.0% for the 20 mW/cm2 threshold. CONCLUSIONS: Assuming that the subjects analyzed were representative of the overall patient population, over 150 patients that received percutaneous abscess drainage during the study period would have been eligible for MB-PDT at the time of drainage, with smaller abscesses being more amenable for treatment. This technique could potentially reduce abscess recurrence, duration of drainage catheter placement, and reliance on systemic antibiotics. These results motivate a future Phase 2 clinical trial following successful completion of the ongoing safety study.

Transperineal ultrasound for assessment of fistulas and abscesses: a pictorial essay.

Perianal fistulas and abscesses may be cryptogenetic or associated with inflammatory bowel disease (IBD), specifically Crohn's disease. Proper identification and classification of these lesions are paramount for correct therapeutic management. Current diagnostic modalities include MRI (magnetic resonance imaging), EUS (endoscopic ultrasound), EUA (exam under anaesthesia) and recently, transperineal ultrasound (TPUS). The latter has been proposed as a noninvasive, easily available and cost-effective technique to diagnose, assess and follow up perianal disease particularly in IBD patients. This pictorial review focuses on the role of TPUS in clinical practice, highlighting the features of fistulas and abscesses.

Clinical impact and cost-effectiveness of noncontrast MRI in the evaluation of suspected appendiceal abscesses in children.

BACKGROUND: Noncontrast MRI has been shown to be feasible in children with postappendectomy abscesses and helps guide clinical management, but its role in preoperative appendiceal abscesses is unclear. PURPOSE: To determine the cost-effectiveness and impact on clinical management of noncontrast MRI in pediatric patients with suspected appendiceal abscess, both pre- and postappendectomy. STUDY TYPE: Retrospective cohort study. POPULATION: In all, 82 children under the age of 18 years with suspected appendiceal abscess on ultrasound. FIELD STRENGTH/SEQUENCE: Diffusion-weighted imaging and T2 -weighted single-shot fast spin-echo imaging of the abdomen and pelvis at 1.5T and 3T. ASSESSMENT: The presence, location, size, and apparent diffusion coefficient (ADC) of fluid collections and the presence of a drainage path was noted by three pediatric radiologists. Imaging time, completeness of the exam, and impact on clinical management was recorded. The incremental cost-effectiveness ratio was calculated for MRI relative to CT, taking into account hospital charges, radiation exposure, and risk of adverse reaction to iodinated contrast. STATISTICAL TESTS: Descriptive statistics were used. Intraclass correlation coefficient and Fleiss' kappa were used to assess interobserver variation. Proportions were compared using Fisher's exact test (statistical significance at P < 0.05). RESULTS: MRI confirmed the presence of collections in most cases, with alternative diagnosis established in 10 patients (Tubo-ovarian abscess n = 7, Crohn's disease, ileal anastomotic leak, and Birkitts lymphoma each n = 1). MRI showed the presence of a safe drainage pathway in 92-97% of pelvic abscesses and 86-98% of abdominal abscesses compared with 7-10% and 75-81%, respectively, for ultrasound. MR was cost-effective compared with CT, taking into account the direct charges, risk of radiation induced cancer, and adverse reaction to iodinated contrast. DATA CONCLUSION: Noncontrast MR is cost-effective and affects clinical management in a significant proportion of children with suspected appendiceal abscesses. LEVEL OF EVIDENCE: 5 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2019.

Clinical value of high-resolution (5-17 MHz) echo-color Doppler (ECD) for identifying filling materials and assessment of damage or complications in aesthetic medicine/surgery.

PURPOSE: The purpose of this retrospective study is to evaluate the role of echo-color-Doppler (ECD) imaging in identifying a series of characteristics pursuant to aesthetic filling material such as their degree of absorbability and their potential complications which include their propensity to stimulate the formation of encapsulated foreign-body granulomas. In the latter case, ECD can be of aid by giving indication for surgical therapy. MATERIALS AND METHODS: Over a 4-year period, we studied 180 patients (60 ♂) who underwent an aesthetic medical/surgical treatment. We used ECD to evaluate the implant material, its thickness, the injection site, the integrity of dermal layers and the presence of any associated complications. RESULTS: In 97% (174/180) of our patients, we were able to identify the type of material used; furthermore, 57% of patients had a hyaluronic acid implant, 14% a lipofilling and 29% a non-absorbable filler (with 10% of silicone). In 6/180 (3%), we could not recognize the material used; 89% (161/180) of our patients presented post-injection complications; moreover, 67% showed peri-implant dermal-hypodermal thickening areas with adjacent lymphostasis, 6% displayed an abnormal implant site, and 17% showed inflammation with encapsulated foreign-body granulomas that required subsequent surgical excision. Biopsy samples were obtained from 37/180 patients (21%); among these, 31 patients had an ECD evidence of granuloma and on 6 patients we were not able to define the injected material. Histopathological examination identified 29 granulomas, 5 sterile abscesses and 3 chronic inflammations in the absence of granuloma. ECD showed an overall 78% diagnostic accuracy, with 90% sensitivity and 37% specificity in detecting filler granulomas. CONCLUSION: ECD is a low-cost technique that allows to identify filling materials and to assess the complications of an esthetic medical/surgical treatment.

Pediatric lateral neck infections - Computed tomography vs ultrasound on initial evaluation.

OBJECTIVE: Review the evaluation of children with a deep lateral neck infection and define the impact of initial imaging modality on outcomes and costs. METHOD: Case series, pediatric patients <18 years of age admitted to a tertiary care hospital with lateral neck infection between 01/01/14-05/31/16 as identified by ICD-9 and ICD-10 codes: 289.3 (lymphadenitis, unspecified), 682.1 (cellulitis and abscess of neck), 683 (acute lymphadenitis), I88.9 (nonspecific lymphadenitis, unspecified), L02.11 (cutaneous abscess of neck), L03.221 (cellulitis of neck), and L03.222 (acute lymphangitis of neck). Patients were divided into two groups based on initial imaging modality: primary ultrasound or primary computed tomography. Differences in length of stay, type and total number of imaging studies obtained, number of procedures, hospital readmission, and hospital cost were compared between cohorts. RESULTS: There were 40 (31%) primary ultrasound and 88 (69%) primary computed tomography patients (128 total). Median length of stay was 46 (IQR: 25,90) hours (1.9 days) for primary ultrasound and 63 (IQR: 39,88) hours (2.6 days) for primary computed tomography patients (p = 0.33). Drainage was performed in 48% of both groups. Additional imaging occurred in 17 (43%) primary ultrasound and 18 (20%) primary computed tomography patients (p = 0.02). Readmission occurred in 8 patients (6.3%). Retropharyngeal infection was encountered in 13 patients (10%); this was only discovered in patients who had a computed tomography performed. Median cost per primary ultrasound patients was $5363 (IQR: 3011, 7920) and $5992 (IQR: 3450, 8060) for primary computed tomography patients. CONCLUSIONS: The primary imaging modality (ultrasound or computed tomography) used to work-up children with a lateral neck infection did not impact length of stay or hospital cost. However, a significant subset had a coexisting retropharyngeal infection that was only identified on computed tomography. Future studies are needed to identify appropriate criteria for imaging in the work-up of lateral neck infections.

Power Doppler ultrasound assessment of vascularization in hidradenitis suppurativa lesions.

BACKGROUND: Ultrasound (US) and Power Doppler (PD) US are useful tools to study and monitor the patients with hidradenitis suppurativa (HS). OBJECTIVE: Describe the PD signal of HS nodules, abscesses and fistulas. METHODS: A retrospective analysis of PD in mild, moderate and severe HS patients, collecting all demographic and clinical data. The lesions were classified according to their US morphology, describing the vascular degree - high, moderate and minimal - and distribution - peripheral, internal and mixed. Statistical analysis was performed using odds ratio and bivariate regression. RESULTS: A total of 241 lesions, 62 nodules, 64 abscesses, 99 simple fistulas and 16 complex fistulas, from 61 patients with HS, were included. Vascular distribution was defined peripheral in 143/241, mixed in 55/241 and internal in 0/241 lesions, regardless the clinical type. Qualitative Doppler showed high vascularization in 44/241 lesions, moderate in 79/241 and minimal in 75/241, despite the clinical type. All lesions showed resistive index <0.7. Age, disease's duration, size of the lesions, high Sartorius score and high BMI showed positive statistical correlation with both PD signal and mixed vascular distribution. No statistical significance was evidenced for vascular degree measurements. LIMITATIONS: US cannot detect lesions <0.1 mm. CONCLUSION: Vascular distribution of HS lesions can be evaluated by PD with additional relevant information for earlier and better disease management.

An Easy-to-Make, Low-Cost Ultrasound Phantom for Simulation Training in Abscess Identification and Aspiration.

We have created a low-cost and easy to make phantom for abscess identification using point-of-care ultrasound. The phantom also allows needle tracking and abscess aspiration using ultrasound guidance.

Usefulness of two- and three-dimensional transesophageal echocardiography in the assessment of proximal left coronary system compression by a paraprosthetic aortic valve abscess.

Paraprosthetic aortic valve abscess represents a rare, but lethal complication of infective endocarditis. We report a case of proximal left coronary system compression by a paraprosthetic aortic valve abscess whose detection was augmented using live/real time three-dimensional transesophageal echocardiography. Our case illustrates the usefulness of combined two- and three-dimensional transesophageal echocardiography in detecting this finding.

Ultrasound-Guided Percutaneous Catheter Drainage of Large Breast Abscesses in Lactating Women: How to Preserve Breastfeeding Safely.

INTRODUCTION: Management of breast abscess in lactating women remains controversial. During pregnancy, women may develop different kinds of benign breast lesions that could require a surgical incision performed under general anesthesia with consequent breastfeeding interruption. The purpose of this study was to prospectively evaluate the management of large breast abscesses with ultrasound-assisted drainage aiming at breastfeeding preservation. MATERIALS AND METHODS: 34 lactating women with a diagnosis of unilateral breast abscess have been treated with an ultrasound (US)-assisted drainage of the abscess. A pigtail catheter was inserted into the fluid collection using the Seldinger technique under US guide and connected to a three stop way to allow drainage and irrigation of the cavity until its resolution. RESULTS: All procedures have been found safe and well tolerated. No recurrence was observed and breastfeeding was never interrupted. CONCLUSIONS: The described technique allows to avoid surgery and to preserve breastfeeding in well-selected patients with a safe, well-tolerated and cost-effective procedure.

Role of tridimensional endoanal ultrasound (3D-EAUS) in the preoperative assessment of perianal sepsis.

PURPOSE: The aim of this study was to evaluate the accuracy of tridimensional endoanal ultrasound (3D-EAUS) in the diagnosis of perianal sepsis comparing the results with the surgical findings, considered as reference standard. METHODS: From January 2009 to January 2013, all the patients referred for the assessment and treatment of perianal sepsis with suspected anorectal origin were enrolled in the study. All patients gave informed written consent. Prior to surgery, all the patients underwent anamnestic evaluation, clinical examination, and unenhanced and H2O2-enhanced 3D-EAUS. Surgery was performed by a colorectal surgeon blinded to the 3D-EAUS results. RESULTS: A total of 212 patients with suspected perianal suppurations were assessed during the study period. In 12 patients, the H2O2-enhanced 3D-EAUS was not performed, and so, they were excluded from the study. Very good agreement between 3D-EAUS and examination under anesthesia (EUA) in the classification of primary fistula tracts (kappa = 0.93) and in the identification of fistula internal opening (kappa = 0.97) was found. There was a good concordance (kappa = 0.71) between 3D-EAUS and surgery in the detection of fistula secondary extensions. The overall sensitivity and specificity of 3D-EAUS in the diagnosis of perianal sepsis were 98.3 and 91.3% respectively. CONCLUSION: 3D-EAUS is a safe and reliable technique in the assessment of perianal sepsis. It may assist the surgeon in delineating the fistula tract anatomy and in determining the origin of sepsis, supporting the preoperative planning of definitive and appropriate surgical therapy.

Surgical vs ultrasound-guided drainage of deep neck space abscesses: a randomized controlled trial: surgical vs ultrasound drainage.

INTRODUCTION: Deep neck space abscesses (DNAs) are relatively common otolaryngology-head and neck surgery emergencies and can result in significant morbidity with potential mortality. Traditionally, surgical incision and drainage (I&D) with antibiotics has been the mainstay of treatment. Some reports have suggested that ultrasound-guided drainage (USD) is a less invasive and effective alternative in select cases. OBJECTIVES: To compare I&D vs USD of well-defined DNAs, using a randomized controlled clinical trial design. The primary outcome measure was effectiveness (length of hospital stay (LOHS) and safety), and the secondary outcome measure was overall cost to the healthcare system. METHODS: Patients presenting to the University of Alberta Emergency Department with a well-defined deep neck space abscess were recruited in the study. Patients were randomized to surgical or US-guided drainage, placed on intravenous antibiotics and admitted with airway precautions. Following drainage with either intervention, abscess collections were cultured and drains were left in place until discharge. RESULTS: Seventeen patients were recruited in the study. We found a significant difference in mean LOHS between patients who underwent USD (3.1 days) vs I&D (5.2 days). We identified significant cost savings associated with USD with a 41% cost reduction in comparison to I&D. CONCLUSIONS: USD drainage of deep neck space abscesses in a certain patient population is effective, safe, and results in a significant cost savings to the healthcare system.

Pitfalls of CT for deep neck abscess imaging assessment: a retrospective review of 162 cases.

OBJECTIVES: To investigate the diagnostic value of contrast-enhanced computed tomography (CT) for the prediction of deep neck abscesses in different deep neck spaces and to evaluate the false-positive results. METHOD: We retrospectively analysed the clinical charts, CT examinations, surgical findings, bacteriology, pathological examinations and complications of hospitalised patients with a diagnosis of deep neck abscess from 2004 to 2010. The positive predictive values (PPV) for the prediction of abscesses by CT scan in different deep neck spaces were calculated individually on the basis of surgical findings. RESULTS: A total of 162 patients were included in this study. All patients received both intravenous antibiotics and surgical drainage. The parapharyngeal space was the most commonly involved space. The overall PPV for the prediction of deep neck abscess with contrast-enhanced CT was 79.6%. The PPV was 91.3% when more than one deep neck space was involved but only 50.0% in patients with isolated retropharyngeal abscesses. In the false-positive group, cellulitis was the most common final result, followed by cystic degeneration of cervical metastases. Five specimens taken intra-operatively revealed malignancy and four of these were not infected. CONCLUSIONS: There are some limitations affecting the differentiation of abscesses and cellulitis, particularly in the retropharyngeal space. A central necrotic cervical metastatic lymph node may sometimes also mimic a simple pyogenic deep neck abscess on both clinical pictures and CT images. Routine biopsy of the tissue must be performed during surgical drainage.

Incremental role of three-dimensional transesophageal echocardiography in the assessment of mitral-aortic intervalvular fibrosa abscess.

We report a case of an elderly patient in whom live/real time three-dimensional transesophageal echocardiography (3DTEE) provided definitive diagnosis of mitral-aortic intervalvular fibrosa abscess. This could not be done by two-dimensional transthoracic echocardiography (2DTTE) and two-dimensional transesophageal echocardiography (2DTEE). 3DTEE was also helpful in ruling out associated mitral valve endocarditis, which was initially suspected by 2DTEE leading to a mitral valve sparing surgery. Thus, 3DTEE provided incremental information over 2DTTE and 2DTEE in this patient.

A simplified method for anal ultrasonography: preliminary report.

BACKGROUND: Anal endosonography (AES) is able to reliably visualize and identify anal sphincter abnormalities. However, dedicated probes are quite expensive. AIM: We describe a simple and less costly method to perform AES in a unit that already has echoendoscopes available by inserting the endoscope through a disposable anoscope filled with standard ultrasound gel. PATIENTS: Subjects without anal abnormalities and patients with anal disease (abscesses, fistulas) were evaluated. RESULTS: Good-quality images were obtained in both controls and patients, with optimal visualization of the anatomic structures and pathologic features. The latter (abscesses, fistulas) were always confirmed by magnetic resonance imaging. CONCLUSIONS: This simple and less costly method allows to perform good-quality AES in units having echoendoscopes availability, without the need of a more expensive dedicated probe.

Dropped gallstones and surgical clips after cholecystectomy: CT assessment.

AIM: To describe the spectrum of computed tomographic (CT) findings in patients with dropped gallstones or dropped surgical clips after cholecystectomy. MATERIALS AND METHODS: Seventeen patients diagnosed with dropped gallstones and 26 patients with dropped surgical clips on computed tomography after cholecystectomies were included in this study. The CT scans were evaluated for the number, location, size, and density of dropped gallstones or surgical clips and for the presence of an abscess. The cases were evaluated for the outcome on clinical and/or CT follow-up. RESULTS: The location for dropped gallstones and dropped surgical clips after cholecystectomy was the Morrison's pouch in 17 and 12 patients, respectively. There were 9 abscesses in the study, all located in the Morrison's pouch. Duration from surgery to observation of abscess on computed tomography ranged from 5 days to more than 4.7 years. None of the patients with a dropped surgical clip from cholecystectomy developed an associated abscess. CONCLUSIONS: Subhepatic location was the most common location for dropped gallstones with associated abscess and for dropped surgical clips. Dropped cholecystectomy clips are not associated with increased risk of abscess formation and therefore do not need screening follow-up or operative removal. Abscess formation around dropped gallstone is a more common complication and requires surgical treatment in most when associated with an abscess.