Peter L. Munk

Dual Energy Computed Tomography in tophaceous gout

Objective: To evaluate the potential utility of a dual energy CT (DECT) scan in assessing urate deposits among patients with tophaceous gout, and obtain computerised quantification of tophus volume in peripheral joints. Methods: 20 consecutive patients with tophaceous gout and 10 control patients with other arthritic conditions were included. DECT scans were performed using a renal stone colour-coding protocol that specifically assessed the chemical composition of the material (ie, urate coloured in red, calcium coloured in blue). An automated volumetric assessment of DECT was used to measure the volume of urate deposits in all peripheral joint areas. Results: All 20 patients with gout showed red colour-coded urate deposits on their DECT scans, whereas none of 10 controls showed urate deposits. DECT scans revealed a total of 440 areas of urate deposition in 20 patients, whereas physical examination showed 111 areas of urate deposition (mean 22 vs 6 per patient, respectively, p<0.001). Total urate volume in a given patient ranged from 0.63 cm3 to 249.13 cm3, with a mean of 40.20 cm3. Conclusions: DECT scans can produce obvious colour displays for urate deposits and help to identify subclinical tophus deposits. Furthermore, tophus volume can be measured by DECT scans through an automated volume estimation procedure.

Imaging of soft tissue infections.

Imaging of soft tissue infections has traditionally been a challenging and difficult undertaking. With the advent of cross-sectional imaging it has improved dramatically. Ultrasound, CT, and particularly MR imaging have greatly improved the ability to evaluate infectious conditions of soft tissue. This article outlines and provides examples of some of the cardinal manifestations of soft tissue infections as seen using a spectrum of different imaging modalities including plain radiography, nuclear medicine, and the cross-sectional imaging techniques mentioned previously. The soft tissue infections can be categorized in a number of different fashions. Discussed are soft tissue infections under the following headings: 1 Primary soft tissue infections: This category includes such entities as abscesses, pyomyositis, cellulitis, and other superficial infections, in particular necrotizing fasciitis 2 Soft tissue infection associated with joint infections: This includes extension of infection from septic joints and the surrounding soft tissues; septic tenosynovitis; infected bursa, either associated with joints or separate from them; and paraspinal abscesses 3 Soft tissue infections related to underlying or associated osteomyelitis 4 The diabetic foot 5 Parasitic infestations 6 Miscellaneous

Association of Biomarkers With Pre-Radiographically Defined and Radiographically Defined Knee Osteoarthritis in a Population-Based Study

OBJECTIVE To evaluate 10 biomarkers in magnetic resonance imaging (MRI)-determined, pre-radiographically defined osteoarthritis (pre-ROA) and radiographically defined OA (ROA) in a population-based cohort of subjects with symptomatic knee pain. METHODS Two hundred one white subjects with knee pain, ages 40-79 years, were classified into OA subgroups according to MRI-based cartilage (MRC) scores (range 0-4) and Kellgren/Lawrence (K/L) grades of radiographic severity (range 0-4): no OA (MRC score 0, K/L grade<2), pre-ROA (MRC score>or=1, K/L grade<2), or ROA (MRC score>or=1, K/L grade>or=2). Urine and serum samples were assessed for levels of the following biomarkers: urinary biomarkers C-telopeptide of type II collagen (uCTX-II), type II and types I and II collagen cleavage neoepitopes (uC2C and uC1,2C, respectively), and N-telopeptide of type I collagen, and serum biomarkers sC1,2C, sC2C, C-propeptide of type II procollagen (sCPII), chondroitin sulfate 846 epitope, cartilage oligomeric matrix protein, and hyaluronic acid. Multicategory logistic regression was performed to evaluate the association of OA subgroup with individual biomarker levels and biomarker ratios, adjusted for age, sex, and body mass index. RESULTS The risk of ROA versus no OA increased with increasing levels of uCTX-II (odds ratio [OR] 3.12, 95% confidence interval [95% CI] 1.35-7.21), uC2C (OR 2.13, 95% CI 1.04-4.37), and uC1,2C (OR 2.07, 95% CI 1.06-4.04), and was reduced in association with high levels of sCPII (OR 0.53, 95% CI 0.30-0.94). The risk of pre-ROA versus no OA increased with increasing levels of uC2C (OR 2.06, 95% CI 1.05-4.01) and uC1,2C (OR 2.06, 95% CI 1.12-3.77). The ratios of type II collagen degradation markers to collagen synthesis markers were better than individual biomarkers at differentiating the OA subgroups, e.g., the ratio of [uCTX-II][uC1,2C] to sCPII was associated with a risk of ROA versus no OA of 3.47 (95% CI 1.34-9.03) and a risk of pre-ROA versus no OA of 2.56 (95% CI 1.03-6.40). CONCLUSION Different cartilage degradation markers are associated with pre-ROA than are associated with ROA, indicating that their use as diagnostic markers depends on the stage of OA. Biomarker ratios contrasting cartilage degradation with cartilage synthesis are better able to differentiate OA stages compared with levels of the individual markers.

Combined Cementoplasty and Radiofrequency Ablation in the Treatment of Painful Neoplastic Lesions of Bone

PURPOSE To assess the safety and effectiveness of combined radiofrequency (RF) ablation and cementoplasty in the treatment of painful neoplastic lesions of bone. MATERIALS AND METHODS The authors performed a retrospective analysis of 25 combined treatments comprising RF ablation followed by injection of polymethylmethacrylate cement performed in 19 patients during a 22-month period. Patients ranged in age from 42 to 82 years (mean, 58.9 years) and included five women and 14 men. Eleven vertebrae (eight lumbar and three thoracic), nine acetabulae, three sacra, one pubis, and one humerus were treated with a total of 36 RF ablations (in several instances, overlapping ablations were used). The location of the primary neoplasm, lesion size, pain before and after the procedure (as determined with a 10-point visual analog scale [VAS]), number of RF treatments, type of device used for cementoplasty, RF time, cement volume, and extravasation were documented. RESULTS A total of 25 combined RF ablations and cementoplasties were performed. The technical success rate was 100% (25 of 25 treatments). There were seven minor complications: six limited cement extravasations and a transient thermal nerve injury. The mean RF time was 9.1 minutes (range, 6-12 minutes). The mean cement volume injected was 6.1 mL (range, 0.8-16 mL). The mean preprocedure pain (as measured with a VAS) was 7.9 (range, 7.0-9.0) and the mean posttreatment pain was 4.2 (range, 0-6); the difference was statistically significant (mean score, 4.08; 95% confidence interval: 3.92, 4.87; P < .0001) using a paired t test. CONCLUSIONS Combined RF ablation and cementoplasty appears to be safe and effective in the treatment of painful neoplastic lesions of bone.

Quantitative evaluation of metal artifact reduction techniques

To develop a technique to quantify artifact, and to use it to compare the effectiveness of several approaches to metal artifact reduction, including view angle tilting and increasing the slice select and image bandwidths (BWs), in terms of metal artifact reduction, noise, and blur.

THE USE OF RADIOLOGICALLY PLACED GASTROSTOMY TUBES IN HEAD AND NECK CANCER PATIENTS RECEIVING RADIOTHERAPY

PURPOSE Patients undergoing radiotherapy to the head and neck area frequently experience radiation reactions that can markedly restrict oral intake, require hospitalization, and occasionally cause treatment interruptions. The Vancouver Cancer Center (VCC) has recently employed radiologically placed gastrostomy tubes (G-tubes) in the management of this problem. A review of the patients on whom this procedure had been performed is the subject of this review. METHODS AND MATERIALS Thirty-four patients had gastrostomy tubes inserted under radiologic guidance. This group is compared to a control group matched for age, sex, irradiated volume, and radiation dose, who did not have gastrostomy tubes. Patients with gastrostomy tubes were divided into two categories: (a) patients who had tubes inserted in anticipation of severe reactions, and (b) patients who developed severe radiation reactions necessitating nutritional support. RESULTS The gastrostomy group consisted of 65% males with an average age of 59 years and stage range of II (12%), III (24%), and IV (65%). In both the elective group and the nonelective group, patients maintained their weight at 95 to 97% of the pretreatment weight, at follow-up of 6 weeks and 3 months. This compared with an average weight loss in the control group of 9% at 6 weeks and 12% at 3 months. The length of hospitalization was a mean of 4.9 days in the elective group and 19 days in the nonelective group. Complication were low compared to those documented in the literature, but included two tube migrations, two aspirations, and one gastrointestinal bleed. CONCLUSIONS We believe that gastrostomy tubes contribute significantly to the management of patients with head and neck cancer, particularly in maintanence of nutrition, and they may decrease the need for hospitalization.

MR imaging features of bizarre parosteal osteochondromatous proliferation of bone (Nora's lesion)

The purpose of this study was to review the imaging findings of three patients with bizarre parosteal osteochrondromatous proliferation of bone (BPOP). The plain radiographs and MRI images of three patients with BPOP were obtained and retrospectively reviewed. In two cases, BPOP involved the feet. In one case BPOP involved the hand. In all three cases, plain radiographs showed a well-defined calcium containing mass adjacent to the cortical surface of the adjacent bone. The underlying bone appeared normal in all cases. On MRI, the lesion was of low signal intensity on T1 weighted sequences in all cases. On FSE T2 weighted and STIR sequences, the lesion was of high signal in all cases. The cortex, medullary cavity and adjacent soft tissues appeared normal in all cases. While BPOP is rare and often confused with a variety of both benign and malignant lesions, there are specific radiological findings that may help to distinguish BPOP from many of its mimickers.

Radiological features of synovial cell sarcoma

Synovial cell sarcoma is an uncommon soft-tissue malignant tumour. These tumours have common radiological features with a variety of both benign and malignant lesions. However, there is a variety of imaging findings that can suggest a pre-biopsy diagnosis of synovial cell sarcoma. This pictorial review aims to describe the imaging features of synovial sarcoma in a series of cases with various age ranges and tumour locations. In addition, the pathology, staging, prognosis and management of synovial sarcoma is briefly discussed.

Image-Guided Musculoskeletal Biopsy

Image guidance allows safe passage of needles, often into small and otherwise inaccessible lesions, and into the portions of the lesion most likely to yield useful samples, while avoiding damage to important structures. This article hopes to provide a useful guide to image-guided musculoskeletal biopsy for radiologists in practice and in training.

Percutaneous Vertebral Augmentation: Vertebroplasty, Kyphoplasty and Skyphoplasty

Percutaneous vertebroplasty is a safe, inexpensive, and effective interventional vertebral augmentation technique that provides pain relief and stabilization in carefully selected patients with severe back pain due to vertebral compression. Complications from percutaneous vertebroplasty can be devastating, but are rare and avoidable with application of a meticulous technique. Percutaneous vertebroplasty has a role in the management pathway of patients presenting with painful vertebral compression fractures. Kyphoplasty uses a balloon tamp with the aim of restoring vertebral body height, improving kyphotic deformity, and creating a cavity into which bone cement is injected. Kyphoplasty is as effective and safe as vertebroplasty in treatment of painful vertebral compression fractures. Skyphoplasty, a modification of kyphoplasty, is a promising new technique.