Diagnostic study, Level II.

No abstract

The purpose of this study was to assess the diagnostic accuracy of whole-body MRI (WB-MRI) at 1.5 T or 3 T compared with FDG-PET-CT in the follow-up of patients suffering from colorectal cancer. In a retrospective study, 24 patients with a history of colorectal cancer and suspected tumour recurrence underwent FDG-PET-CT and WB-MRI with the use of parallel imaging (PAT) for follow-up. High resolution coronal T1w-TSE and STIR sequences at four body levels, HASTE imaging of the lungs, contrast-enhanced T1w- and T2w-TSE sequences of the liver, brain, abdomen and pelvis were performed, using WB-MRI at either 1.5 T (n = 14) or 3 T (n = 10). Presence of local recurrent tumour, lymph node involvement and distant metastatic disease was confirmed using radiological follow-up within at least 5 months as a standard of reference. Seventy seven malignant foci in 17 of 24 patients (71%) were detected with both WB-MRI and PET-CT. Both investigations concordantly revealed two local recurrent tumours. PET-CT detected significantly more lymph node metastases (sensitivity 93%, n = 27/29) than WB-MRI (sensitivity 63%, n = 18/29). PET-CT and WB-MRI achieved a similar sensitivity for the detection of organ metastases with 80% and 78%, respectively (37/46 and 36/46). WB-MRI detected brain metastases in one patient. One false-positive local tumour recurrence was indicated by PET-CT. Overall diagnostic accuracy for PET-CT was 91% (sensitivity 86%, specificity 96%) and 83% for WB-MRI (sensitivity 72%, specificity 93%), respectively. Examination time for WB-MRI at 1.5 T and 3 T was 52 min and 43 min, respectively; examination time for PET-CT was 103 min. Initial results suggest that differences in accuracy for local and distant metastases detection using FDG-PET-CT and WB-MRI for integrated screening of tumour recurrence in colorectal cancer depend on the location of the malignant focus. Our results show that nodal disease is better detected using PET-CT, whereas organ disease is depicted equally well by both investigations.

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Experience with infected shoulder arthroplasty is limited. Treatment options are either one-or two-stage reimplantation, débridement with retention of the prosthesis, resection arthroplasty or arthrodesis. We retrospectively analysed ten patients with an infected shoulder prosthesis and evaluated the diagnostic and therapeutic management as well as the clinical outcome, assessed by the Constant score, Neer's criteria and the mean abduction ability. We identified an infecting organism before surgery in nine patients. Four patients were treated by two-stage exchange reimplantation, five by resection arthroplasty and one underwent serial débridement combined with vacuum-irrigation therapy. Infection was eradicated in all patients of this series. The mean Constant score in resected patients was 32.7, in patients treated by stage exchange 40.1 (no difference) and we measured 90 points in the patient with retention of the implant. In patients treated by resection arthroplasty, merely the mean abduction yielded a better result (63 vs 31°) than in patients treated by two-stage exchange-with the pain level being identical in both groups. Treatment of infected shoulder implants in patients who often have to deal with concomitant diseases remains unsatisfactory. Two-stage exchange procedures yielded only slightly better functional results than resection arthroplasty, which should be considered in cases of elderly or chronically ill patients because it offers good pain relief. Serial débridement combined with irrigation therapy is a new method which offers good clinical results, however with an unknown risk of persisting infection. The authors recommend isolating the infecting organism prior to surgery to allow the administration of organism-specific antibiotics as early as possible during surgery in order to efficiently eradicate the infection.

The meta-analysis shows that the use of navigation systems in UKA leads to a more precise component position. Whether the more accurate position in UKA results in a better clinical outcome or long-term survival is yet unknown. Nevertheless, as a precise implant position appears to be beneficial, the use of navigation should be recommended for UKA. The limits defined by the manufacturers for an optimal positioning are not consistent.

This paper first presents a brief overview about the mechanism of wear particle formation as well as wear particle characteristics in metal-on-polyethylene and metal-on-metal artificial hip joints. The biological effects of such particles are then described, focusing on the inflammatory response induced by each type of particles as well as on how metal wear products may be the source of a T lymphocyte-mediated specific immune response, early adverse tissue responses, and genotoxicity. Finally, some of the current in vivo models used for the analysis of tissue response to various wear particles are presented.