Real-time identification of life-threatening necrotizing soft-tissue infections using indocyanine green fluorescence imaging

Significance

Necrotizing soft-tissue infections (NSTIs) are life-threatening infections with a cumulative case fatality rate of 21%. The initial presentation of an NSTI is non-specific, frequently leading to misdiagnosis and delays in care. No current strategies yield an accurate, real-time diagnosis of an NSTI.

Aim

A first-in-kind, observational, clinical pilot study tested the hypothesis that measurable fluorescence signal voids occur in NSTI-affected tissues following intravenous administration and imaging of perfusion-based indocyanine green (ICG) fluorescence. This hypothesis is based on the established knowledge that NSTI is associated with local microvascular thrombosis.

Approach

Adult patients presenting to the Emergency Department of a tertiary care medical center at high risk for NSTI were prospectively enrolled and imaged with a commercial fluorescence imager. Single-frame fluorescence snapshot and first-pass perfusion kinetic parameters-ingress slope (IS), time-to-peak (TTP) intensity, and maximum fluorescence intensity (IMAX)-were quantified using a dynamic contrast-enhanced fluorescence imaging technique. Clinical variables (comorbidities, blood laboratory values), fluorescence parameters, and fluorescence signal-to-background ratios (SBRs) were compared to final infection diagnosis.

Results

Fourteen patients were enrolled and imaged (six NSTI, six cellulitis, one diabetes mellitus-associated gangrene, and one osteomyelitis). Clinical variables demonstrated no statistically significant differences between NSTI and non-NSTI patient groups (p -value ≥ 0.22 ). All NSTI cases exhibited prominent fluorescence signal voids in affected tissues, including tissue features not visible to the naked eye. All cellulitis cases exhibited a hyperemic response with increased fluorescence and no distinct signal voids. Median lesion-to-background tissue SBRs based on snapshot, IS, TTP, and IMAX parameter maps ranged from 3.2 to 9.1, 2.2 to 33.8, 1.0 to 7.5, and 1.5 to 12.7, respectively, for the NSTI patient group. All fluorescence parameters except TTP demonstrated statistically significant differences between NSTI and cellulitis patient groups (p -value < 0.05 ).

Conclusions

Real-time, accurate discrimination of NSTIs compared with non-necrotizing infections may be possible with perfusion-based ICG fluorescence imaging.

Ultrasonography for Skin and Soft Tissue Infections, Noninfectious Cysts, Foreign Bodies, and Burns in the Critical Care Setting

There are multiple opportunities for the use of ultrasonography in the diagnosis of skin and soft tissue differentials. Ultrasonography is inexpensive, easily reproducible, and able to provide real-time data in situations where condition changes and progression are common. Not only does bedside ultrasonography provide the clinician an in-depth look beyond epidermal structures into body cavities, it remains a safe, nonionizing radiating, effective, cost-efficient, reliable, and accessible tool for the emergency management of life- and limb-threatening integumentary infections. Unnecessary invasive procedures are minimized, providing improved patient outcomes. Integumentary abnormalities secondary to trauma, surgery, and hospitalization are common among critical care patients. This article provides a brief overview and evidence-based recommendations for the use of ultrasonography in the critical care setting for integumentary system conditions, including common skin and soft tissue differentials, foreign bodies, and burn depth assessment.

Spectrum of imaging findings in soft-tissue necrosis

Soft tissue necrosis can occur at different tissue levels, with numerous underlying causes. In this pictorial review, we highlight myonecrosis, and its accompanying stages, fat necrosis, devitalized soft tissue seen with infection, and necrotizing soft tissue infections. Imaging examples are provided with each entity.

ACR Appropriateness Criteria® Suspected Osteomyelitis, Septic Arthritis, or Soft Tissue Infection (Excluding Spine and Diabetic Foot): 2022 Update

Musculoskeletal infections involve bones, joints, and soft tissues. These infections are a common clinical scenario in both outpatient and emergent settings. Although radiography provides baseline findings, a multimodality approach is often implemented to provide more detailed information on the extent of infection involvement and complications. MRI with intravenous contrast is excellent for the evaluation of musculoskeletal infections and is the most sensitive for diagnosing osteomyelitis. MRI, CT, and ultrasound can be useful for joint and soft tissue infections. When MRI or CT is contraindicated, bone scans and the appropriate utilization of other nuclear medicine scans can be implemented for aiding in the diagnostic imaging of infection, especially with metal hardware and arthroplasty artifacts on MRI and CT. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer-reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances in which peer-reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Role of point-of-care ultrasound (POCUS) in the diagnosis of an abscess in paediatric skin and soft tissue infections: a systematic review and meta-analysis

AIMS

To evaluate the effect of point-of-care ultrasound (POCUS) for the diagnosis of an abscess and to compare the diagnostic accuracy of POCUS and physical examination (PE) in paediatric patients with skin and soft tissue infections (SSTI) in the emergency department.

MATERIAL AND METHODS

A comprehensive literature search was carried out to identify Englishlanguage studies on POCUS for differentiating an abscess from cellulitis in paediatric patients with SSTI. The quality of the study was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 tool, and pooled sensitivity and specificity of various POCUS findings were determined.

RESULTS

Seven studies with a total of 870 patients were included. There was significant heterogeneity across the included studies. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio for the diagnosis of abscess by POCUS were 0.90 (95% confidence interval [CI], 0.82-0.95), 0.80 (95% CI, 0.72-0.86), 4.5 (95% CI, 3.1-6.4), 0.13 (95% CI, 0.07-0.23), and 36 (95% CI, 17-75), respectively, with an area under the curve (AUC) was 0.89 (95% CI, 0.86-0.91). Four studies provided data regarding the PE method. The pooled sensitivity, specificity, and AUC of PE for the abscess were 0.84 (95% CI, 0.80-0.88), 0.69 (95% CI, 0.62-0.76), and 0.85 (95% CI, 0.81-0.88).

CONCLUSIONS

POCUS is useful in identifying abscesses in paediatric patients with SSTI in emergency department, especially when PE is equivocal and outperforms PE alone.

POINT-OF-CARE ULTRASOUND IN THE EARLY DIAGNOSIS OF NECROTIZING FASCIITIS

OBJECTIVE

The aim: To detect the ultrasonographic signs of necrotizing fasciitis (NF) suitable for its early diagnosis.

PATIENTS AND METHODS

Materials and methods: Eigty two patients with soft tissue infection, including 14 with necrotizing faciitis, were examined by ultrasonography at the admission. Ultrasonografic features were compared to intraoperative findings by the same surgeon.

RESULTS

Results: The thickening of subcutaneous tissue had high sensitivity (100%), but low specificity (5.8%). The hypoechoic and hyperechoic zones had the shape of "cobblestone" with sensitivity - 78.5%, specificity - 33.8%. Higher specificity (69.1%) had sign of "cobblestone separation" on two layers. The presence of fluid above the fascia (sensitivity - 71.4%; specificity - 69.1%), thickening of the fascia (sensitivity - 85.7%; specificity - 58.8%), indistinctness of the fascia edges (sensitivity - 85.7%; specificity - 66.1%) and loss of fascial homogeneity (sensitivity - 71.4%, specificity - 66.1%) were noted in early stages of NF. Advanced cases of NF were accompanied by the dissection of thick¬ened fascia with a strip of fluid (sensitivity - 57.1%, specificity - 92.6%) and accumulation of a fluid under the fascia (sensitivity - 28.5%, specificity - 95.5%). The muscles thickening (sensitivity - 28.5%; specificity - 67.6%), skin thickening (sensitivity - 57.1%; specificity - 58.8%), and loss of the skin's lower edge clarity (sensitivity - 57.1%; specificity - 63.2%) don't have diagnostic value without other signs of NF.

CONCLUSION

Conclusions: Point-of-care ultrasonography allows visualization of soft tissue changes that may be hidden in the initial stages of necrotizing fasciitis and should be recommended for implementation as mandatory method of examination in patients with suspected surgical soft tissue infection.

Iatrogenic subcutaneous emphysema in aesthetic breast augmentation Medicolegal aspects

The aim of the present study was to investigate clinical results and medico-legal aspects related to the surgical procedure of mini breast augmentation. In the present case, a 28-year-old young woman with bilateral mammary hypoplasia underwent surgery, under local anesthesia, with the placement of 150 cc breast implants in the sub-glandular plane. We report a case of dramatic isolated subcutaneous emphysema without pneumothorax and pneumomediastinum to be related in terms of a causal link to the surgical procedure which the patient underwent. The plastic surgeon proceeded to replace a breast implant that presumably, represented the vehicle of transmission of the suspected pathogen responsible for the infection, to become a causal role for the infectious manifestation. This case report is an emblematic example of the need for a careful and correct surgical procedure, in order to avoid serious consequences as in the case in question, burdened by the occurrence of unsafe conditions for the patient. Compliance with the guidelines and the technical datasheet of breast implants is essential in order to avoid the concrete hypothesis of professional liability. KEY WORDS: Aesthetic breast augmentation, Breast implant, Iatrogenic subcutaneous emphysema.

An unexpected host in a soft-tissue lesion of thigh

Rhinosporidiosis is an enigmatic entity and poses a major health problem in the developing countries of South-East Asia. A soft friable polypoid nasal mass is the most common presentation, while sparse literature is available on extranasal involvement. We describe the case of a 35-year-old female patient who presented with a slow-growing soft-tissue swelling with ulceration over the thigh. On clinical and radiological examination, a provisional diagnosis of soft-tissue neoplasm was made. After resection, histopathological sections showed a closely packed cyst with innumerable endospores. The present case report documents the rare occurrence of an incidentally detected cutaneous rhinosporidiosis causing diagnostic difficulty.

Point-of-Care Ultrasonography

Point-of-care ultrasonography (POCUS) is performed by a physician at the bedside and is standard practice in obstetric, emergency, and musculoskeletal medicine. When compared with formal sonography, POCUS is equivalent in screening for abdominal aortic aneurysm and as accurate in diagnosing deep venous thrombosis. POCUS has high accuracy for diagnosing pneumonia and detecting acute decompensated heart failure but is less accurate than computed tomography for identifying pulmonary embolism. POCUS confirmation of intrauterine pregnancy rules out an ectopic pregnancy. In the third trimester of high-risk pregnancies, umbilical artery Doppler ultrasonography can improve perinatal outcomes. Musculoskeletal POCUS is used to diagnose and guide treatment of many joint and soft tissue conditions. It is as accurate as magnetic resonance imaging in the diagnosis of complete rotator cuff tears. Ultrasound guidance improves outcomes in the placement of central venous catheters and fluid drainage from body cavities and lumbar punctures. Ultrasonography can reduce the use of CT for diagnosis of appendicitis; however, negative scan results do not rule out disease. POCUS can accurately diagnose and rule out gallbladder pathology, and is effective for diagnosing urolithiasis. Focused cardiac ultrasonography can detect pericardial effusion and decreased systolic function, but is less accurate than lung ultrasonography at diagnosing acute heart failure. Limited evidence demonstrates a benefit of diagnosing testicular and gynecologic conditions. The American College of Emergency Physicians, the American Institute of Ultrasound in Medicine, the Society for Academic Emergency Medicine, the American College of Radiology, and others offer POCUS training. Training standards for POCUS have been defined for residency programs but are less established for credentialing.

Necrotizing Myositis: A Rare Necrotizing Soft Tissue Infection Involving Muscle

INTRODUCTION

Necrotizing myositis (NM) is an extremely rare necrotizing soft tissue infection involving muscle. Unlike similar infections (eg, necrotizing fasciitis, clostridial myonecrosis) that can be more readily diagnosed, NM can have a benign presentation then rapidly progress into a life-threatening condition with a mortality rate of 100% without surgical intervention.

CASE REPORT

A 74-year-old man with a history of prostate cancer with radiation therapy, seed implants, and 2 transurethral resection procedures presented to the emergency department after a fall. He was initially diagnosed and treated for urosepsis. Sixteen hours after presentation, he complained of pain and swelling of his right groin. Computed tomography of the abdomen and pelvis showed gas findings suspicious for necrotizing infection of the bilateral thighs. Surgical exploration revealed NM. Separate cultures from the left thigh and bladder grew Streptococcus intermedius, Clostridium clostridioforme, and Peptostreptococcus, suggesting a possible common source of infection from the prostate gland or the osteomyelitic pubic symphysis, which subsequently spread to the bilateral thighs.

CONCLUSIONS

To the best of the authors' knowledge, this is the first reported case of S intermedius and C clostridioforme causing NM. A high index of suspicion is required for extremely rare conditions like NM, because early diagnosis and surgical intervention significantly reduce mortality.

Ultrasound-Guided Drainage for Pediatric Soft Tissue Abscesses Decreases Clinical Failure Rates Compared to Drainage Without Ultrasound: A Retrospective Study

OBJECTIVES

Soft tissue abscesses are common in the pediatric emergency department (ED). Ultrasound (US) can be used to both diagnose soft tissue abscesses as well as guide drainage. We hypothesized that clinical failure rates would be less in pediatric patients with suspected skin abscesses when evaluated with US.

METHODS

We performed a retrospective review of suspected pediatric skin abscesses at 4 EDs over a 22-month period. Cases were identified through electronic medical record descriptions, discharge diagnoses, and US database records. Data on US use, findings, and outcomes were abstracted to an electronic database. Comparisons between groups included US versus non-US (primary outcome) as well as surgical drainage vs nonsurgical drainage (secondary outcome).

RESULTS

A total of 377 patients were seen with concern for a potential skin abscess; 141 patients (37.4%) underwent US imaging during their visit, and 239 (63.4%) underwent incision and drainage (I&D) during their ED stay: 90 with US and 149 without. The failure rate for patients evaluated with US was significantly lower than that for those evaluated without US (4.4% versus 15.6%; P < .005). Thirty-four (11.3%) of the 302 patients with a diagnosis of an abscess failed therapy: 19 (8.2%) after I&D and 15 (21.1%) after nonsurgical management. Failure after I&D was associated with a smaller abscess cavity on US imaging (17.2 versus 44.8 mm³ ; P < .05).

CONCLUSIONS

The use of US for patients with a suspected skin abscess was associated with a reduction in the amount of clinical failure rates after both surgical drainage and nonsurgical therapy. Ultrasound should be used when evaluating or treating patients with abscesses.

In patients presenting to the emergency department with skin and soft tissue infections what is the diagnostic accuracy of point-of-care ultrasonography for the diagnosis of abscess compared to the current standard of care? A systematic review and meta-analysis

OBJECTIVES

The primary objective of this systematic review was to determine the accuracy of point-of-care ultrasonography (POCUS) in diagnosing abscess in emergency department (ED) patients with skin and soft tissue infections (SSTI). The secondary objective was the accuracy of POCUS in the paediatric population subgroup.

SETTING

Prospective studies set in emergency departments.

PARTICIPANTS

Emergency department patients (adult and paediatric) presenting with SSTI and suspected abscess.

PRIMARY AND SECONDARY OUTCOME MEASURES

This systematic review was conducted according to Cochrane Handbook guidelines, and the following databases were searched: PubMed, MEDLINE, EMBASE and the Cochrane database of systematic reviews (1946-2015). We included prospective cohort and case-control studies investigating ED patients with SSTI and abscess or cellulitis, a defined POCUS protocol, a clearly defined gold standard for abscess and a contingency table describing sensitivity and specificity. Two reviewers independently ascertained all potentially relevant citations for methodologic quality according to QUADAS-2 criteria. The primary outcome measure was the sensitivity and specificity of POCUS for abscess. A preplanned subgroup (secondary) analysis examined the effects in paediatric populations, and changes in management were explored post hoc.

RESULTS

Of 3028 articles, 8 were identified meeting inclusion criteria; all were rated as good to excellent according to QUADAS-2 criteria. Combined test characteristics of POCUS on the ED diagnosis of abscess for patients with SSTI were as follows: sensitivity 96.2% (95% CI 91.1% to 98.4%), specificity 82.9% (95% CI 60.4% to 93.9%), positive likelihood ratio 5.63 (95% CI 2.2 to 14.6) and negative likelihood ratio 0.05 (95% CI 0.01 to 0.11).

CONCLUSIONS

A total of 8 studies of good-to-excellent quality were included in this review. The use of POCUS helps differentiate abscess from cellulitis in ED patients with SSTI.

TRIAL REGISTRATION NUMBER

CRD42015017115.

Necrotizing soft tissue infection of the right anterolateral abdominal wall caused by a ruptured gangrenous appendix in an elderly diabetic patient

Necrotizing soft tissue infections (NSTIs) of the abdominal wall usually occur when either a common superficial soft tissue infection progresses down to, or an injury (e.g. knife stab) penetrates, the investing muscle fascia, or an intra-abdominal infection spreads directly to the muscle layers of the abdominal wall. These infections are severe and associated with significant morbidity and mortality. We present an 83-year-old female diabetic patient who was admitted to the surgical emergency department complaining of right abdominal pain after a fall to the floor. She had previously received oral antibiotics for a minor superficial skin infection attributed to her subcutaneous use of insulin. On admission she exhibited signs of agitation and dyspnoea with hypotension and tachycardia (systolic arterial pressure 90mmHg, heart rate >110 bpm, oxygen saturation 88%). Furthermore, she had a tender right abdomen but without any demonstrable pathology on her skin or crepitus. Arterial blood gases revealed metabolic acidosis and hypoxaemia. An abdominal computed tomography (CT) scan demonstrated signs of infection of the entire right anterior abdominal wall and the LRINEC score was calculated to be 13. Subsequent operative aggressive necrosectomy of all the involved layers of the right anterolateral abdominal wall sparing the peritoneum was undertaken. Unfortunately, the patient died the next day due to multiple organ failure.

Ultrasound for the Evaluation of Skin and Soft Tissue Infections

Skin and sott tissue infections, including abscesses and cellulitides, are common problems seen by physicians. The treatment of soft tissue infections varies depending on the depth of infection or the presence of a fluid collection requiring incision and drainage. Ultrasound is a valuable tool in the evaluation of skin and soft tissue infections, enhancing our ability to diagnose an abscess cavity or deeper infection and has been shown to be more reliable than clinical exam alone. The judicious use of ultrasound allows for more appropriate patient care and management of their underlying infection. It can prevent an unnecessary procedure or identify occult abscesses that may go on to develop a more severe infection requiring hospitalization. In this article,we discuss the utility of ultrasound as a diagnostic tool for skin and soft tissue infections, techniques to optimize scanning, and the potential drawbacks of its use.

Quantitative assessment of bone microvascularization after osteocutaneous flap transplantation using contrast-enhanced ultrasound (CEUS)

BACKGROUND

Extensive wound defects frequently have to be covered by free flap transplantation. A monitoring device for measuring capillary level perfusion of bone is currently not available.

OBJECTIVE

The aim of the study was to detect complications after osteocutaneous flap transplantation using contrast-enhanced ultrasound (CEUS). Additionally quantitative analysis was performed by special perfusion software (QONTRAST®; Bracco, Italy).

METHODS

22 patients were examined after osteocutaneous flap transplantation during the first 72 h after operation. CEUS was performed with a linear transducer (6-9 MHz, LOGIQ E9/GE) after bolus injections of 2.4 ml ultrasound contrast agent (SonoVue®; Bracco, Italy). The osseous perfusion and soft tissue perfusion were analyzed separately and quantitative perfusion analysis was performed. Five patients had to undergo reoperation due to compromised flap microvascularization.

RESULTS

In all 5 complications reduced osseous and soft tissue perfusion was seen using CEUS. Additionally using the perfusion parameters TTP (time to PEAK), RBV (regional blood volume), RBF (regional blood flow) und MTT (mean transit time), significantly lower soft tissue and osseous perfusion was detected.

CONCLUSION

CEUS seems to be capable of detecting vascular disturbances and of assessing microvascularization of the osseous component after osteocutaneous flap transplantation.

Ultrasonography of the non-traumatic lesions of the fingers. Pictorial essay

The purpose of this pictorial essay is to illustrate the ultrasonographic aspects of the non-traumatic lesions of the fingers. Diffuse (especially dactylitis) and localized (tumors, tophi, calcinosis, etc) lesions of the digits are discussed and illustrated. For a better understanding, the US images are compared with the clinical aspect of the pathological fingers.

Emergency ultrasonography in patients with clinically suspected soft tissue infection of the legs

INTRODUCTION

We aimed to retrospectively review the ultrasonography (US) findings of patients with clinically suspected soft tissue infection of the legs and to determine whether there is a correlation between US diagnosis and further clinical management.

METHODS

We reviewed the US findings of consecutive patients with clinically suspected soft tissue infection of the legs who were referred for emergency US during a consecutive two-year period. The indications for US were recorded and the findings evaluated. The effect of the US findings on further clinical management (medication alone versus medication with surgical intervention [SI]) was reviewed.

RESULTS

A total of 51 legs from 38 patients were enrolled in the study. The most common indication for US was to rule out necrotising fasciitis (35.3%). The most frequent US diagnosis was isolated cellulitis (21.6%). Both groups of patients (with and without abscess) were treated with medication with or without SI. There was no statistically significant correlation between the presence or absence of abscess and further clinical management (p = 0.216), between the size (length and thickness) of the abscess and the type of SI (p = 0.687 and 0.243, respectively)

CONCLUSION

In our study, the most frequent US diagnosis was isolated cellulitis, and we found no significant correlation between US findings and clinical management (medication or SI). Our results should encourage sonologists to evaluate in detail patients with clinically suspected soft tissue infection of the legs and to provide information regarding each layer of tissue studied.

Bedside ultrasound performed by novices for the detection of abscess in ED patients with soft tissue infections

OBJECTIVE

The objective was to compare bedside ultrasound (US) to clinical examination for the detection of abscess.

METHODS

This is a 24-month prospective, observational emergency department (ED) study. Adults with suspected nondraining abscess with planned incision and drainage (I&D) are included in the study. Exclusion criteria are spontaneous drainage and perineal, perirectal, or intraoral location. Before I&D, a second ED physician conducts an US and records the presence or absence of findings suggestive of abscess. A positive I&D of the suspected abscess is the criterion standard. The treating practitioner is blinded to the US results. Ultrasound is performed by novice ED physicians. The findings of the US, the prediction of pus from the clinician and the ultrasonographer in 3 strata (low, indeterminate, definite), and the results of the I&D (pus/no pus) are recorded onto data sheets. Measures of association are reported and Fisher's Exact test is used.

RESULTS

Forty patients were enrolled. The sensitivity of novice sonographers to predict a positive I&D with US was 0.97 (0.83-1.00), the specificity was 0.67 (0.24-0.94), the positive likelihood ratio was 2.90, the negative likelihood ratio was 0.04, and the area under the receiver operating characteristic curve was 0.85 (0.66-1.00). Clinical examination yielded a sensitivity of 0.76 (0.58-0.89), specificity of 0.83 (0.36-0.99), positive likelihood ratio of 4.50, negative likelihood ratio of 0.29, and area under the receiver operating characteristic curve of 0.75 (0.50-1.00).

CONCLUSION

Novice ED sonographers can identify abscesses with only minimal US training. Identification of abscess on US may change management of cutaneous abscesses.

[Differential radiodiagnosis of odontogenic mandibular osteomyelitis accompanied by trigeminal neuropathy]

This paper deals with the results of radiation examination in 43 patients with clinical manifestations of mandibular osteomyelitis. In 13 of them, the disease was accompanied by trigeminal neuropathy. The radiation semiotics of the changes occurring in the mandibular bone and its adjacent soft tissues in different phases of osteomyelitis is described. Comparative analysis of orthopantomograms and the images obtained by multislice spiral computed tomography has revealed the advantage of the latter in identifying insignificant changes in bone tissue and damages to the mandibular canal. Ultrasound study is of more informative value in detecting soft tissue changes in this area. High-technology radiodiagnostic techniques play a leading role in the differentiation of odontogenic and non-odontogenic trigeminal neuropathies.

Assessment of a training curriculum for emergency ultrasound for pediatric soft tissue infections

OBJECTIVES

The objective was to evaluate a training protocol for pediatric emergency physicians (EPs) learning emergency ultrasound (EUS) for the evaluation of skin and soft tissue infections (SSTIs) by assessing technical ability and interrater reliability.

METHODS

Pediatric emergency medicine (EM) fellows and attending physicians completed a 1-day training course taught by an expert emergency sonologist. After the course, EPs performed proctored examinations on patients with SSTIs until they reached predefined performance criteria, after which they performed independent EUS examinations. All EUS examinations were recorded using still images and video clips that were reviewed and rated by the expert sonologist on four technical measures and combined into a composite score. The expert's opinion regarding the presence or absence of an abscess was also compared to the study sonologist's opinion and analyzed for interrater reliability.

RESULTS

Seven EPs performed 107 EUS examinations. The mean (±SD) composite score for the evaluation of technical ability for the first EUS was 3.3 ± 0.14 (on a 4-point scale), indicating a high level of quality following the training course. There was a small amount of improvement in the quality score (0.015, 95% confidence interval [CI] = 0.0003 to 0.03) with each consecutive EUS examination. The interrater reliability between the sonologist and the expert for the presence of an abscess as measured by the kappa statistic was 0.80 (95% CI = 0.63 to 0.97), indicating substantial agreement.

CONCLUSIONS

After a brief training program, pediatric EPs can perform technically successful emergency EUS examination of SSTIs, with excellent agreement with an expert sonologist.

[Multislice spiral computed tomography in the diagnosis of osteomyelitis]

This paper deals with the results of a radiation study in 34 patients with the clinical manifestations of maxillofacial osteomyelitides. It describes the radiation semiotics of changes occurring in the bone and its surrounding soft tissues of the maxillofacial region in different phases of osteomyelitis. Comparative analysis of orthopantograms and images obtained by multislice spiral computed tomography revealed the benefits of the latter in detecting soft tissue changes and subtle bone alterations.

Utility of bedside sonography to distinguish soft tissue abnormalities from joint effusions in the emergency department

OBJECTIVE

The purpose of this study was to determine the utility of bedside sonography to differentiate soft tissue abnormalities from joint effusions.

METHODS

We conducted a retrospective review of emergency department (ED) patients presenting with joint pain, erythema, and swelling who received bedside sonography. The ED sonographic examinations were performed by emergency physician sonologists who were not involved in clinical assessment and management of these patients. The treating physician's opinions regarding the probability of joint effusion and need for aspiration were documented in the sonography log before the sonographic examination was performed. The bedside sonograms of all patients included in this study were also reviewed for accuracy. Descriptive statistics were used to summarize the data.

RESULTS

A total of 54 patients (mean age +/- SD, 41 +/- 18.9 years) were identified over a 1-year period. The symptomatic joints in our study subjects were as follows: knee, 24 of 54 (44%); elbow, 21 of 54 (38%); ankle, 8 of 54 (15%); and metatarsophalangeal joint, 1 of 54 (2%). Twenty-two of 54 patients (40.7%; 95% confidence interval [CI], 27.6%-53.8%) were found to have joint effusions on sonography. Sonography altered management in 35 of 54 patients (65%; 95% CI, 52%-77.5%). Joint aspiration was planned in 39 of 54 cases (72.2%; 95% CI, 60.2%-84.1%) before sonography. After sonography, only 20 of these patients (37%; 95% CI, 24.1%-49.9%) underwent joint aspiration. There was a statistically significant difference in treatment plans after the addition of bedside sonographic results (P < .01).

CONCLUSIONS

Our study suggests that bedside sonography is useful in differentiating joint effusions from soft tissue abnormalities and directing appropriate therapy.

Acute upper airway obstruction caused by Stenotrophomonas maltophilia soft tissue infection

A previously healthy 71-y-old male developed acute upper airway obstruction caused by a Stenotrophomonas maltophilia infection of the mucocutaneous and soft tissue of the neck. Ventilator support was provided via a small-calibre endotracheal tube. Stenotrophomonas was susceptible only to levofloxacin and cotrimoxazole. Antibiotic therapy rapidly improved the soft tissue oedema, allowing extubation and discharge from the intensive care unit.

Use of ultrasound elastography for skin and subcutaneous abscesses

OBJECTIVE

Elastography is a new adjunct to real-time ultrasound imaging that overlays traditional B-mode imaging with a color graphic representation of tissue elasticity. Soft tissue infections are common presenting conditions in the emergency department, and elastography has the potential to help in diagnosis and treatment of evolving soft tissue infections as they progress from induration to fluctuant abscesses, but to our knowledge, no studies of elastography in superficial soft tissue have been published. We hypothesized that elastography would provide increased information regarding skin abscesses.

METHODS

This was a prospective study of patients with suspected skin abscesses requiring surgical drainage in the emergency department of an urban tertiary care center. Abscesses were imaged with B-mode imaging and elastography in orthogonal planes. Ultrasound images were analyzed for characteristics of the elastographic images.

RESULTS

A total of 50 patients with suspected skin abscesses underwent B-mode imaging and elastography. Elastography accurately differentiated the induration surrounding the abscess from the surrounding healthy tissue, a differentiation that was not visible on B-mode imaging. The elastographic properties of the abscess cavity were variable and not always seen, even with purulence identified during incision and drainage. In some cases, elastography identified abscess cavities not seen on B-mode imaging. When seen, the abscess cavity could be characterized by elastographic color and speckle patterns.

CONCLUSIONS

Elastography identified the tissue induration and some abscess cavities not seen on B-mode imaging. It offers a way to characterize abscesses that may be useful clinically, but more research is needed.

Safety and effectiveness of extracorporeal shockwave therapy: results of a rabbit model of chronic osteomyelitis

Extracorporeal shockwave therapy (ESWT) is applied successfully in various orthopedic disorders. Since shockwaves have demonstrated significant bactericidal effectiveness in vitro, safety and effectiveness of ESWT in vivo were evaluated in a rabbit model of osteomyelitis. Chronic osteomyelitis was induced by injecting sodium morrhuate and Staphylococcus aureus into the proximal tibia of 12 New Zealand white rabbits. Four and five wk after the initial operation, soft focused ESWT was applied twice to the infected limbs. Clinical parameters and laboratory values were followed and blood samples were taken for culture before and 30 min after ESWT. Following sacrifice after 8 wk, lungs, spleen and kidneys were studied histologically for signs of sepsis and secondary infection. Tibial osteomyelitis was assessed clinically, and by radiologic, microbiologic and histologic procedures. Signs of bacterial spreading were not detectable after ESWT, neither in blood cultures nor in histologic analyses of representative organs. Temperature, body weight, C-reactive protein and white blood cell levels also remained unchanged after ESWT. Of particular interest, histologic scores of osteomyelitis were significantly decreased in the ESWT-group compared to the untreated control (p = 0.019). However, S. aureus was still detectable in tissue samples of all animals. This is the first study investigating the effects of ESWT applied to infected target areas. ESWT of infected bone did neither induce bacterial spreading nor worsening of infection, and the results suggest the reported treatment protocol of ESWT to be beneficial in the treatment of chronic bone infections.

Comparison of the image quality of various fixed and dose modulated protocols for soft tissue neck CT on a GE Lightspeed scanner

PURPOSE

Up-to-date CT scanners provide high quality soft tissue imaging of the neck, but scanning protocols often are not optimized regarding radiation dose. Thus, we tried to find a dose-optimized protocol for soft tissue imaging of the neck.

MATERIAL AND METHODS

70 patients were scanned with a 16-row CT-scanner (Lightspeed, GE) with seven different protocols. We used four fixed tube current settings (225, 200, 175 and 150 mA; corresponding CTDI(vol)=10.6, 9.5, 8.3 and 7.1 mGy) and three z-axis dose modulations with a relatively high, moderate and low dose (calculated CTDI(vol)=10.5, 9.1, 7.7 mGy). Representative slices of seven anatomical regions (from the nasopharynx to the aortic arch) were subjectively judged by two radiologists with respect to image quality (five-point rating scale for noise and sharpness). For each protocol and for each judged anatomical region we determined and compared mean values regarding image quality and local tube current. For each protocol, mean values regarding the volume CT dose index (CTDI(vol)) and the dose-length product (DLP) were statistically compared. Moreover, using the software CT-Expo the respective effective doses and the cumulative organ doses of the thyroid gland were compared.

RESULTS

For a fixed tube current of at least 200 mA (CTDI(vol)=9.5 mGy) and for dose modulations with a moderate or high dose adjustment (calculated CTDI(vol)=9.1 and 10.5 mGy) the image quality was sufficient to excellent. As compared to a fixed tube current of 200 mA, dose modulation with a moderate dose adjustment improved the image quality in regions more vulnerable to noise-related artifacts such as at the level of the shoulder, without a noteworthy difference regarding the DLP. However, the cumulative organ dose of the thyroid gland was 17% lower using dose modulation with a moderate dose adjustment as compared to the fixed tube current of 200 mA. Thus, for a comparison with other scanners, we recommend dose modulation and an averaged CTDI(vol)<9 mGy (or a DLP<250 mGycm).

CONCLUSION

A combination of dose modulation and an averaged CTDI(vol)<9 mGy or a DLP<250 mGycm yields sufficient image quality for soft tissue CT-imaging of the neck.

[Ultrasound evaluation of traumatic process course after endoscopic operations for pyoinflammatory diseases of soft tissues]

Soft tissues dynamic ultrasound investigation was applied for diagnostics of pyoinflammatory diseases. Ultrasound image correlated with intermuscular liquid formations (abscess, phlegmon) of soft tissues was revealed in 65 observations (100%). On the basis of findings 21 (32.3%) patients underwent surgical treatment of leg and gluteal region phlegmons and abscesses with application of traditional methods. Endoscopic operations on account of pyoinflammatory diseases of soft tissues were carried out in 44 (67.7%) patients. Ultrasound monitoring of traumatic process course was conducted. It is ascertained that total regress of purulent process occurs by the 14th day of postoperative period. Traumatic process regresses more rapid after endoscopic operations in comparison with traditional open methods.

Technetium-99m-labelled sulesomab (LeukoScan) in the evaluation of soft tissue infections

OBJECTIVE

To perform a retrospective review of all patients receiving technetium-99m ((99m)Tc)-labelled sulesomab over a 4-year period to determine if soft tissue infections can be accurately identified.

METHODS AND MATERIALS

We reviewed the results of 124 (99m)Tc-sulesomab studies performed over a 4-year period. Of these, 34 were performed for undiagnosed fever in which soft tissue infection was suspected to be the main cause. The patients' clinical notes, microbiology reports and other imaging findings were reviewed to determine the clinical outcome following the scan. The scans were regarded as being true-positives if (i) uptake correlated with the site from which fluid or tissue was obtained and which grew bacteria, and/or (ii) the site of abnormality was reported as having an infection on other imaging or (iii) there was a clinical correlation with the referring clinician's evaluation of the patient. Planar imaging was performed using standard protocols, together with single-photon emission computed tomography (if required) at 1 and 4 h after injection of 20-30 mCi (740-1,110 MBq) (99m)Tc-sulesomab.

RESULTS

Three patients were unevaluable. In the remaining 31 patients, 21 (99m)Tc-sulesomab studies were regarded as true-positives and 6 patients had true-negative scans. One patient had a false-positive scan (abnormal uptake with negative microbiology) and 3 had false-negative scans (infection confirmed but a negative scan).

CONCLUSION

In suspected soft tissue infection, (99m)Tc-sulesomab imaging has a sensitivity of 88% with a specificity of 86% and overall accuracy of 87%. (99m)Tc-sulesomab provides an accurate method of imaging for suspected soft tissue infection, which is also fast and convenient, as cell labelling is not required.

Potential role of FDG PET in the setting of diabetic neuro-osteoarthropathy: can it differentiate uncomplicated Charcot's neuroarthropathy from osteomyelitis and soft-tissue infection?

BACKGROUND

This paper is based on the results from an ongoing prospective trial designed to investigate the usefulness of FDG PET in the complicated diabetic foot.

AIM

To investigate the potential utility of FDG PET imaging in the setting of acute neuropathic osteoarthropathy (Charcot's foot).

PATIENTS AND METHODS

A total of 63 patients, in four groups, were evaluated. The groups were: (A) 17 patients with a clinical diagnosis of Charcot's neuroarthropathy (11 men, six women; mean age: 59.4+/-8.6 years); (B) 21 patients with uncomplicated diabetic foot (16 men, five women; mean age: 63+/-10 years); (C) 20 non-diabetic patients with normal lower extremities (12 men, eight women; mean age 54+/-19 years); and (D) five patients with proven osteomyelitis secondary to complicated diabetic foot (three men, two women; mean age: 61.2+/-13.9 years). Five patients in group A had foot ulcer and intermediate to high degree of suspicion for superimposed osteomyelitis. Each subject underwent FDG PET imaging of the lower extremities in addition to MRI and the findings were compared with the final diagnostic outcome based on histopathology and clinical follow-up. The images were examined visually for focal abnormalities. Regions of interest were assigned to the sites of abnormal FDG uptake for calculating maximum standardized uptake value (SUVmax). Two important clinical decision-making issues were explored: (1) whether FDG PET shows a definitive uptake pattern in Charcot's neuroarthropathy and if so whether that could be utilized to differentiate it from other complicated forms of diabetic foot like osteomyelitis and cellulitis, which is frequently a diagnostic challenge in this clinical setting; and (2) how accurate FDG PET is in detection soft tissue infection in patients with Charcot's foot. These issues were examined by utilizing FDG PET findings along with MRI results in the same patient.

RESULTS

We observed a low degree of diffuse FDG uptake in the Charcot's joints. This was clearly distinguishable from the normal joints. The SUVmax in the Charcot's lesions varied from 0.7 to 2.4 (mean, 1.3+/-0.4) while those of midfoot of the normal control subjects and the uncomplicated diabetic foot ranged from 0.2 to 0.7 (mean 0.42+/-0.12) and from 0.2 to 0.8 (mean 0.5+/-0.16), respectively. The only patient with Charcot's foot with superimposed osteomyelitis had an SUVmax of 6.5. The SUVmax of the sites of osteomyelitis as a complication of diabetic foot was 2.9-6.2 (mean: 4.38+/-1.39). Unifactorial analysis of variance test yielded a statistical significance in the SUVmax between the four groups (P<0.01). The SUVmax between the normal control groups and the uncomplicated diabetic foot was not statistically significant by the Student's t-test (P>0.05). In the setting of concomitant foot ulcer FDG PET accurately ruled out osteomyelitis. Overall sensitivity and accuracy of FDG PET in the diagnosis of Charcot's foot was 100 and 93.8%, respectively; and for MRI were 76.9 and 75%, respectively. FDG PET showed foci of abnormally enhanced uptake in the soft tissue which was suggestive of inflammation in seven cases (43.75%) which were proven pathologically to be secondary to infection. In only two of these cases the features of soft tissue infection were noted on the magnetic resonance images.

CONCLUSION

The results support a valuable role of FDG PET in the setting of Charcot's neuroarthropathy by reliably differentiating it from osteomyelitis both in general and when foot ulcer is present.

Non-neoplastic conditions presenting as soft-tissue tumours

Review of referrals to our unit over the last 7 years showed that of approximately 750 cases referred as soft-tissue tumours, 132 were subsequently diagnosed as non-neoplastic lesions. The imaging characteristics of these lesions are presented to differentiate them from neoplasms. The most common diagnoses were myositis ossificans, ganglion cyst, abscess/infection, bursitis and synovitis. The imaging features of other rarer conditions will also be discussed.

Imaging of osteomyelitis: current concepts

Osteomyelitis frequently requires more than one imaging technique for an accurate diagnosis. Conventional radiography still remains the first imaging modality. MRI and nuclear medicine are the most sensitive and specific methods for the detection of osteomyelitis. MRI provides more accurate information regarding the extent of the infectious process. Ultrasound represents a noninvasive method to evaluate the involved soft tissues and cortical bone and may provide guidance for diagnostic or therapeutic aspiration, drainage, or tissue biopsy. CT scan can be a useful method to detect early osseous erosion and to document the presence of sequestra. PET and SPECT are highly accurate techniques for the evaluation of chronic osteomyelitis, allowing differentiation from soft tissue infection.

Bedside ultrasound of the soft tissue of the face: A case of early Ludwig’s angina

A case is reported of a 38-year-old man presenting with early Ludwig's angina. It is difficult to differentiate superficial from deep infections of the face and neck by physical examination alone. The diagnosis of this condition with bedside soft tissue ultrasound of the face is described. Ludwig's angina is an uncommon infection of the deep tissues of the face and neck that usually evolves from more superficial infections such as dental abscesses.

Soft tissue and joint infection

Soft tissue infection may be acute or chronic and may be introduced by the haematogenous route, or by inoculation, including surgical infection, or spread from other areas. The spectrum of infecting organism differs in primary infection, in immunodeficiency or when foreign bodies, including prostheses, are present. Bacterial infections are usually more rapid than those due to fungi or atypical organisms. Inflammation usually begins as cellulitis, proceeding through necrosis to cavitation and abscess formation, sometimes complicated by haemorrhage. Imaging, apart from MRI in selected cases, is rarely helpful in the early stages, but early diagnosis of pyomyositis and necrotizing fasciitis is mandatory. When infection is established, US, CT and MRI all have individual value in diagnosis, including biopsy, and in directing therapy, including percutaneous or surgical drainage or debridement. Both MRI and CT are best suited to monitoring progress. Septic arthritis presents as rapidly progressive, destructive arthritis, and early diagnosis is essential to prevent long-term morbidity. Ultrasound offers the best method of detecting early joint effusion and synovial thickening, but aspiration is usually required for diagnosis. In more advanced stages CT is valuable for revealing destructive changes, and MRI for documenting intra-articular changes and detecting inflammation in surrounding bone.

[Necrotizing cutaneous infections and Fournier's gangrene]

Fournier's gangrene is a necrotizing infection of skin and soft tissue of the perineum. Several sources of contamination have been described: cutaneous, urological or anorectal. Anatomy of the perineum helps in the prediction of the extension of the infection. The bacterial flora (usually mixed aero-anaerobic flora) depends on the source of infection: gram-positive cocci (skin source) combined with gram-negative bacilli and anaerobes (urological or anorectal source). CT scan and echography are useful tools for the diagnosis without delaying surgery. In the diagnostic procedure and the management, proctological examination, retrograde uretrography, bowel and urine derivation should be discussed.

The effect of soft-tissue ultrasound on the management of cellulitis in the emergency department

OBJECTIVES

To evaluate the effect of diagnostic soft-tissue ultrasound (US) on management of emergency department (ED) patients with clinical cellulitis.

METHODS

This was a prospective observational study in an urban ED of adult patients with clinical soft-tissue infection without obvious abscess. The treating physician's pretest opinions regarding the need for further drainage procedures and the probability of subcutaneous fluid collection were determined. Emergency sonologists then performed US of the infected area, and the effect on management plan was recorded.

RESULTS

Ultrasound changed the management of patients with cellulitis in 71/126 (56%) of cases. In the pretest group that was believed not to need further drainage, US changed the management in 39/82 (48%), with 33 receiving drainage and 6 receiving further diagnostics or consultation. In the pretest group in which further drainage was believed to be needed, US changed the management in 32/44 (73%), including 16 in whom drainage was eliminated and 16 who had further diagnostic interventions. US had a management effect in all pretest probabilities for fluid from 10% to 90%.

CONCLUSIONS

Soft-tissue US changes physician management in approximately half of patients in the ED with clinical cellulitis. US may guide management of cellulitis by detection of occult abscess, prevention of invasive procedures, and guidance for further imaging or consultation.

Neglected peritonsillar abscess resulting in necrotizing soft tissue infection of the neck and chest wall

Necrotizing soft tissue infection (NSTI) of the neck and chest wall resulting from neglected peritonsillar abscess is a relatively rare but highly lethal surgical condition which has received little attention in the literature. The case of a 54-year-old male patient affected by this unusual infection is reported. Our recent experience and literature data suggest that NSTI resulting from peritonsillar abscess is rapidly spreading and life threatening. High index of suspicion, early diagnosis, broad-spectrum antibiotics and aggressive surgical debridement are essential to its successful treatment.

18F-fluorodeoxyglucose positron emission tomography contributes to the diagnosis and management of infections in patients with multiple myeloma: a study of 165 infectious episodes

PURPOSE

Correctly identifying infection in cancer patients can be challenging. Limited data suggest that positron emission tomography (PET) using fluorine-18 fluorodeoxyglucose (FDG) may be useful for diagnosing infection. To determine the role of FDG-PET in the diagnosis of infection in patients with multiple myeloma (MM).

PATIENTS AND METHODS

The medical records of 248 patients who had FDG-PET performed for MM staging or infection work-up revealing increased uptake at extramedullary sites and/or bones and joints that would be atypical for MM between October 2001 and May 2004 were reviewed to identify infections and evaluate FDG-PET contribution to patient outcome.

RESULTS

One hundred sixty-five infections were identified in 143 adults with MM. Infections involved the respiratory tract [99; pneumonia (93), sinusitis (six)], bone, joint and soft tissues [26; discitis (10), osteomyelitis (nine), septic arthritis (one), cellulitis (six)], vascular system [18; septic thrombophlebitis (nine), infection of implantable catheter (eight), septic emboli (one)], gastrointestinal tract [12; colitis (seven), abdominal abscess (three), and diverticulitis and esophagitis (one each)], and dentition [periodontal abscess (10)]. Infections were caused by bacteria, mycobacteria, fungi, and viruses. FDG-PET detected infection even in patients with severe neutropenia and lymphopenia (30 episodes). The FDG-PET findings identified infections not detectable by other methods (46 episodes), determined extent of infection (32 episodes), and led to modification of work-up and therapy (55 episodes). Twenty silent, but clinically relevant, infections were detected among patients undergoing staging FDG-PET.

CONCLUSION

In patients with MM, FDG-PET is a useful tool for diagnosing and managing infections even in the setting of severe immunosuppression.

ABSCESS: applied bedside sonography for convenient evaluation of superficial soft tissue infections

OBJECTIVES

Soft tissue infections are a common presenting complaint in the emergency department (ED). The authors sought to determine the utility of ED bedside ultrasonography (US) in detecting subcutaneous abscesses.

METHODS

Between August 2003 and November 2004, a prospective, convenience sample of adult patients with a chief complaint suggestive of cellulitis and/or abscess was enrolled. US was performed by attending physicians or residents who had attended a 30-minute training session in soft tissue US. The treating physician recorded a yes/no assessment of whether he or she believed an abscess was present before and after the US examination. Incision and drainage (I + D) was the criterion standard when performed, while resolution on seven-day follow-up was the criterion standard when I + D was not performed.

RESULTS

Sixty-four of 107 patients had I + D-proven abscess, 17 of 107 had negative I + D, and 26 of 107 improved with antibiotic therapy alone. The sensitivity of clinical examination for abscesses was 86% (95% confidence interval [CI] = 76% to 93%), and the specificity was 70% (95% CI = 55% to 82%). The positive predictive value was 81% (95% CI = 70% to 90%), and the negative predictive value was 77% (95% CI = 62% to 88%). The sensitivity of US for abscess was 98% (95% CI = 93% to 100%), and the specificity was 88% (95% CI = 76% to 96%). The positive predictive value was 93% (95% CI = 84% to 97%), and the negative predictive value was 97% (95% CI = 88% to 100%). Of 18 cases in which US disagreed with the clinical examination, US was correct in 17 (94% of cases with disagreement, chi(2) = 14.2, p = 0.0002).

CONCLUSIONS

ED bedside US improves accuracy in detection of superficial abscesses.