[A woman with subcutaneous nodules after buttock augmentation]. / Een vrouw met subcutane noduli na bilvergroting.

Volume augmentation of the buttocks with injectable soft-tissue fillers is a cosmetic procedure; delayed adverse effects include the formation of granulomatous inflammatory nodules. We describe a 35-year-old woman with early-stage Hodgkin's lymphoma with multiple nodular subcutaneous densities on CT scans in both gluteal regions. These were the result of frequent injections with human collagen.

CT arthrography of the human knee to measure cartilage quality with low radiation dose.

OBJECTIVE: Recently, CT arthrography (CTa) was introduced as a non-destructive technique to quantitatively measure cartilage quality in human knees. This study investigated whether this is also possible using lower radiation dose CT protocols. Furthermore, we studied the ability of (lower radiation) CTa to distinguish between local sulphated glycosaminoglycan (sGAG) content differences. DESIGN: Of ten human cadaveric knee joints, six CT scans using different radiation doses (81.33-8.13 mGy) were acquired after intra-articular ioxaglate injection. The capability of CTa to measure overall cartilage quality was determined in seven anatomical regions of interest (ROIs), using equilibrium partitioning of an ionic contrast agent using (EPIC)-microCT (µCT) as reference standard for sGAG content. To test the capability of CTa to spatially distinguish between local differences in sGAG content, we calculated the percentage of pixels incorrectly predicted as having high or low sGAG content by the different CTa protocols. RESULTS: Low radiation dose CTa correlated well with EPIC-µCT in large ROIs (R = 0.78; R(2) = 0.61; P < 0.0001). CTa can also distinguish between high and low sGAG content within a single slice. However, the percentage of incorrectly predicted quality pixels increases (from 35% to 41%) when less radiation is used. This makes is hard or even impossible to differentiate between spatial differences in sGAG content in the lowest radiation scans. CONCLUSIONS: CTa acquired using low radiation exposure, comparable to a regular knee CT, is able to measure overall cartilage quality. Spatial sGAG distribution can also be determined using CTa, however for this purpose a higher radiation dose is necessary. Nevertheless, radiation dose reduction makes CTa suitable for quantitative analysis of cartilage in clinical research.

Clinically applied CT arthrography to measure the sulphated glycosaminoglycan content of cartilage.

OBJECTIVE: Similar to delayed gadolinium enhanced MRI of cartilage, it might be possible to image cartilage quality using CT arthrography (CTa). This study assessed the potential of CTa as a clinically applicable tool to evaluate cartilage quality in terms of sulphated glycosaminoglycan content (sGAG) and structural composition of the extra-cellular matrix (ECM). METHODS: Eleven human cadaveric knee joints were scanned on a clinical CT scanner. Of each knee joint, a regular non-contrast CT (ncCT) and an ioxaglate injected CTa scan were performed. Mean X-ray attenuation of both scans was compared to identify contrast influx in seven anatomical regions of interest (ROIs). All ROIs were rescanned with contrast-enhanced µCT, which served as the reference standard for sGAG content. Mean X-ray attenuation from both ncCT and CTa were correlated with µCT results and analyzed with linear regression. Additionally, residual values from the linear fit between ncCT and µCT were used as a covariate measure to identify the influence of structural composition of cartilage ECM on contrast diffusion into cartilage in CTa scans. RESULTS: CTa resulted in higher X-ray attenuation in cartilage compared to ncCT scans for all anatomical regions. Furthermore, CTa correlated excellent with reference µCT values (sGAG) (R=0.86; R(2)=0.73; P<0.0001). When corrected for structural composition of cartilage ECM, this correlation improved substantially (R=0.95; R(2)=0.90; P<0.0001). CONCLUSIONS: Contrast diffusion into articular cartilage detected with CTa correlates with sGAG content and to a lesser extent with structural composition of cartilage ECM. CTa may be clinically applicable to quantitatively measure the quality of articular cartilage.

Predictive value of geriatric assessment for patients older than 70 years, treated with chemotherapy.

INTRODUCTION: Comprehensive geriatric assessment (CGA) gives useful information on the functional status of older cancer patients. However, its meaning for a proper selection of elderly patients before chemotherapy and, even more important, the influence of chemotherapy on the outcome of geriatric assessment is unknown. METHODS: 202 cancer patients, for whom an indication for chemotherapy was made by the medical oncologist, underwent a GA before start of chemotherapy by Mini Nutritional Assessment (MNA), Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE), Groningen Frailty Index (GFI) and Mini Mental State Examination (MMSE). After completion of a minimum of four cycles of chemotherapy or at 6 months after the start of chemotherapy the GFI and MMSE assessment was repeated. RESULTS: Frailty was shown in 10% of patients by means of MMSE, 32% by MNA, 37% by GFI and in 15% by IQCODE. Compared to patients who received 4 or more cycles of chemotherapy, the MNA and MMSE scores were significantly lower for patients treated with less than 4 cycles (p = 0.001 and p = 0.04 respectively). The mortality rate after start of chemotherapy was increased for patients with low MNA and high GFI scores with hazard ratios of 2.19 (95% confidence interval [CI]: 1.42-3.39; p < 0.001) and 1.80 (95% CI: 1.17-2.78; p = 0.007), respectively. After adjusting for sex, age, purpose of chemotherapy and type of malignancy these hazard ratios remained significant (p < 0.001 and p = 0.004), respectively. Finally, for the 51 patients who underwent repeated post-chemotherapy evaluation by GFI and MMSE, a statistically significant deterioration for the MMSE (p = 0.041) was found but not for the GFI. CONCLUSIONS: Both inferior MNA and MMSE scores increased the probability not to complete chemotherapy. Also, an inferior score for MNA and GFI showed an increased mortality risk after the start of chemotherapy. The mean MMSE score worsened significantly during chemotherapy.

Dose reduction in spiral CT coronary angiography with dual source equipment. Part II. Dose surplus due to slope-up and slope-down of prospective tube current modulation in a phantom model.

PURPOSE: This study was undertaken to estimate surplus radiation dose in retrospectively electrocardiography (ECG)-gated dual-source computed tomography coronary angiography (DSCT-CA) due to the slope-up and slope-down of the tube current using prospectively ECG-triggered tube modulation. MATERIALS AND METHODS: We used an anthropomorphic phantom with an ECG-gated retrospective protocol and a DSCT scanner (Definition, Siemens). We used four tube current modulation algorithms: narrow pulsing window, with tube current reduction to 20% (A) and 4% (B) of peak current; and wide pulsing window, with tube current reduction to 20% (C) and 4% (D). Each algorithm was applied at five heart rates (HR=45, 60, 75, 90 and 120 bpm) with adaptive pitch values (0.2-0.5). Data sets were reconstructed in 5% increments from 0-95% of the R-R interval. Noise was measured at each R-R step in order to identify low noise (100% dose), medium noise (slope-up/down) and high noise (4/20% dose). Width of the transition window (slope-up/slope-down from 4/20% to 100% dose) was calculated. The surplus dose due to slope-up/slope-down was calculated. RESULTS: Surplus dose was 19% (A), 34% (B), 14% (C) and 21% (D). The transition window lasted 10%+10% (slope-up + down) for HR <75 bpm and all HR in C (except for 120 bpm; 25%+15%), 15%+15% for HR >90 bpm (A). For C and D, instead, the slope-up increased with progressively higher HR (10%-25% of the R-R interval, except for 90 bpm, 10%), whereas the slope-down remained constant at 5% (except for 120 bpm; 10%). CONCLUSIONS: The adaptive ECG-pulsing windows produced an increment of the surplus dose with increasing HR. The transition window was a constant source of surplus radiation dose in the range of 14%-34%.

Dose reduction in spiral CT coronary angiography with dual-source equipment. Part I. A phantom study applying different prospective tube current modulation algorithms.

PURPOSE: The authors sought to compare different algorithms for dose reduction in retrospectively echocardiographically (ECG)-gated dual-source computed tomography (CT) coronary angiography (DSCT-CA) in a phantom model. MATERIALS AND METHODS: Weighted CT dose index (CTDI) was measured by using an anthropomorphic phantom in spiral cardiac mode (retrospective ECG gating) at five pitch values adapted with two heart-rate-adaptive ECG pulsing windows using four algorithms: narrow pulsing window, with tube current reduction to 20% (A) and 4% (B) of peak current outside the pulsing window; wide pulsing window, with tube current reduction to 20% (C) and 4% (D). Each algorithm was applied at different heart rates (45, 60, 75, 90, 120 bpm). RESULTS: Mean CTDI volume (CTDIvol) was 36.9+/-9.7 mGy, 23.9+/-5.6 mGy, 49.7+/-16.2 mGy and 38.5+/-12.3 mGy for A, B, C and D, respectively. Consistent dose reduction was observed with protocols applying the 4% tube current reduction (B and D). Using the conversion coefficient for the chest, the mean effective dose was the highest for C (9.6 mSv) and the lowest for B (4.6 mSv). Heart-ratedependent pitch values (pitch=0.2, 0.26, 0.34, 0.43, 0.5) and the use of heart-rate-adaptive ECG pulsing windows provided a significant decrease in the CTDIvol with progressively higher heart rates (45, 60, 75, 90, 120 bpm), despite using wider pulsing windows. CONCLUSIONS: Radiation exposure with DSCT-CA using a narrow pulsing window significantly decreases when compared with a wider pulsing window. When using a protocol with reduced tube current to 4%, the radiation dose is significantly lower.