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.