Microstructural analysis of subchondral bone in knee osteoarthritis.

The results of this study show increased formation of bone in the subchondral areas in advanced stages of osteoarthritis of the knee. These changes seem to be influenced by mechanical factors. INTRODUCTION: Subchondral bone changes seem to contribute to the progression of knee osteoarthritis (OA). This study aimed to analyze subchondral bone microstructure in specimens of late-stage knee OA in respect to articular cartilage damage, meniscus integrity, and knee joint alignment. METHODS: Thirty proximal tibiae of 30 patients (20 female and 10 male) with late-stage OA retrieved during total knee arthroplasty were scanned using a high-resolution micro-computed tomography. The scans were semi-automatically segmented into five volumes of interest. The volumes of interest were then further analyzed using commercially available software. The degree of articular cartilage damage was assessed semi-quantitatively by magnetic resonance imaging before surgery. RESULTS: The mean bone fraction volume (bone volume/total volume (BV/TV)) in all weight-bearing locations was significantly higher compared to the non-weight-bearing reference point below the anterior cruciate ligament (p = 0.000). The mean BV/TV in the medial compartment was significantly higher compared to the lateral compartment (p = 0.007). As for the BV/TV in intact menisci, there was a significantly lower subchondral bone fraction volume compared to subluxated or luxated menisci in the medial (p = 0.020) and lateral compartment (p = 0.005). Varus alignment had a significantly higher subchondral BV/TV in the medial compartment, whereas valgus alignment had a significantly higher subchondral BV/TV in the lateral compartment (p = 0.011). CONCLUSIONS: The results show significant differences of subchondral bone microstructural parameters in respect to cartilage damage, meniscus' structural integrity, and knee joint alignment. Therefore, subchondral bone changes seem to be a secondary process in the late-stage OA of the knee caused by mechanical changes.

Accuracy of 3-Tesla magnetic resonance imaging for the staging of prostate cancer in comparison to the Partin tables.

BACKGROUND: An accurate prediction of final pathological stage is essential for proper patient selection to determine who will experience maximum benefit from radical prostatectomy. In this context, the Partin tables represent one of the most widely used statistical prediction tools. PURPOSE: To compare the accuracy in predicting pathological stage in patients intended for radical prostatectomy between 3-Tesla (T) magnetic resonance imaging (MRI) and the Partin tables in a prospective trial. MATERIAL AND METHODS: 27 men with staging results from 3T MRI using a phased-array coil were compared in terms of staging accuracy with whole-mount-section histopathologic analyses as the standard of reference. Probabilities for pathological stages were estimated according to the Partin tables. Spearman rank correlation and discriminant analysis were calculated to assess relationships. RESULTS: Histopathological evaluation revealed organ-confined disease (OC) in 21 (77.8%) and extracapsular extension (ECE) in six (22.2%) men. Three-Tesla MRI staging was accurate in all patients with OC and in four out of the six men with ECE. Accuracy of local staging was 85.2% (23 of 27). Sensitivity was 66.7% (95% confidence interval [CI] 0.223-0.957) and specificity 100% (95% CI 0.839-1) for the detection of ECE. Findings of MRI and the Partin tables showed a Spearman rho of 0.780 vs. 0.254 for OC and 0.780 vs. 0.363 for ECE, respectively. Compared to the Partin tables, MRI revealed standardized canonical discriminant function coefficients of 0.992 (P<0.001) vs. 0.205 (P=0.432) for OC and 0.965 (P<0.001) vs. 0.329 (P=0.197) for ECE, respectively. CONCLUSION: 3T MRI showed a high accuracy for the staging of clinically localized prostate cancer, and it was significantly more accurate in predicting the final pathological stage than the Partin tables.

Diagnostic accuracy of 3D time-of-flight MR angiography compared with digital subtraction angiography for follow-up of coiled intracranial aneurysms: influence of aneurysm size.

BACKGROUND AND PURPOSE: 3D time-of-flight MR angiography (3D TOF MRA) may be used as noninvasive alternative to digital subtraction angiography (DSA) for the follow-up of patients with intracranial aneurysms treated with Guglielmi detachable coils (GDCs). We aimed to determine the influence of aneurysm size and location on diagnostic accuracy of 3D TOF MRA for follow-up of intracranial aneurysms treated with GDCs. MATERIALS AND METHODS: Two hundred and one 3D TOF MRAs in 127 consecutive patients with 136 aneurysms were compared with DSA as standard of reference. Sensitivity and specificity of 3D TOF MRA for detection of residual or reperfusion of the aneurysms was calculated with regard to aneurysm size and location. RESULTS: Overall sensitivity and specificity of MRA was 88.5% and 92.9%, respectively. Sensitivity was lower for aneurysms

[Three-dimensional ultrasound (3DUS) of the neonatal brain: clinical application in patients of the neonatal intensive care unit (NICU)]. / Dreidimensionaler Ultraschall (3DUS) des neonatalen Gehirns: klinische Anwendbarkeit bei intensivgepflegten Neugeborenen.

AIM: To prospectively evaluate the potential role of 3DUS of the neonatal brain. METHOD: 60 patients from the NICU (gestational age: 25-42 weeks, mean: 31.6 weeks, age: 0 to 90 days, median: 10 days) underwent 2D- and 3D-neurosonography. Both studies were evaluated independently by two observers for comparison. Inter- and intraobserver variability were calculated. RESULTS: All 3DUS were of diagnostic quality and could be performed without sedation. 3DUS missed no essential diagnosis as established by conventional ultrasound (2DUS). Diagnosis included normal or physiologically immature neonatal brains (n = 21), plexus cysts (n = 4), plexus bleedings (n = 10), intraventricular haemorrhages grade I-III (n = 8), periventricular pathology such as periventricular echodensities (n = 4) and periventricular haemorrhages or cerebral infarctions (n = 6), hydrocephalus (n = 4), widened subdural spaces (n = 2) and one suprasellar midline tumour. 3DUS imaging time at the patient (4.8 +/- 2.6 min) was significantly shorter than for 2DUS (9.1 +/- 6.1 min). The additional axial plane provided by 3DUS improved the sonographic potential for differential diagnosis. 3DUS allowed an improved standardisation and documentation potentially valuable for follow-up. No statistically significant differences in intra- and interobserver variability were noted compared to 2DUS. Restrictions of 3DUS were the lack of directional Doppler data and the lower resolution particularly of the purely reconstructed plane. CONCLUSION: Bedside neonatal 3D-neurosonography at the NICU is feasible with diagnostic quality without sedation. 3DUS improves comparison during follow-up, as well as standardisation and documentation, and can be considered a useful adjunct in neonatal 2D-neurosonography.

[Accuracy of renal volume assessment in children by three-dimensional sonography]. / Nierenvolumetrie im Kindesalter: Genauigkeit der dreidimensionalen Sonographie im Vergleich zur konventionellen Sonographie und CT / MRT.

PURPOSE: Prospective evaluation of the accuracy of three-dimensional ultrasound (3DUS) to assess the renal parenchymal volume. MATERIALS AND METHODS: CT, MRI, 2DUS and 3DUS were used to measure the renal volume in 40 patients (range: neonate to 17 years; mean age: 8.95 years). The 3DUS was determined with a Voluson 730 (Kretztechnik, GE) or an external 3D-system (EchoTech, GE) using electromagnetic positioning sensors attached to conventional 2DUS-equipment. The 2DUS volume was calculated with the ellipsoid equation and the 3DUS volume computed with the system integrated software. For CT and MRI, planimetric analysis was used to determine the renal parenchymal volume, whereby the dilated collecting system of a hydronephrosis was subtracted to obtain the real renal parenchymal volume. The results of 2DUS and 3DUS were compared to the results of CT and MRI, and inter- and intraobserver variabilities were calculated. RESULTS: In 74 of 77 kidneys, the 3DUS study was of diagnostic quality. The accuracy of the 3DUS volumes compared well to the CT and MRI volumes with a mean difference of -1.8 +/- 4.6 % versus a mean difference of -2.4 +/- 15.4 % for 2DUS. In normal kidneys, the accuracy was -2.6 +/- 4.4 % for 3DUS and -3.8 +/- 14.7 % for 2DUS. In hydronephrosis, the accuracy was +4.0 +/- 5.9 % and +9.6 +/- 21.3 %, respectively, indicating that 3DUS is more accurate than 2DUS, particularly in kidneys with a dilated collecting system. Inter- and intraobserver variabilities were +/- 7.3 % and +/- 5.3 %. CONCLUSION: For assessing the renal parenchymal volume in children, 3DUS is feasible and comparable to CT and MRI.