Comparison of the diagnostic value of FDG-PET/CT and axillary ultrasound for the detection of lymph node metastases in breast cancer patients.

BACKGROUND: FDG-PET/CT is increasingly being used for breast cancer staging. Its diagnostic accuracy in comparison to ultrasound as the standard non-invasive imaging modality for the evaluation of axillary lymph nodes has yet not been evaluated. PURPOSE: To retrospectively compare the diagnostic value of full-dose, intravenously contrast-enhanced FDG-PET/CT and ultrasound for the detection of lymph node metastases in breast cancer patients. MATERIAL AND METHODS: Ninety patients (one patient with a bilateral carcinoma) (89 women, one man; mean age, 55.5 +/- 16.6 years) suffering from primary breast cancer underwent whole-body FDG-PET/CT and axillary ultrasound. The ipsilateral axillary fossa (n = 91) was evaluated for metastatic spread. The sensitivity, specificity, the positive predictive value (PPV), negative predictive value (NPV), and accuracy of both methods were calculated. The sensitivity and accuracy were statistically compared using the McNemar Test (P <0.05). Analyses were made on a patient basis. The number of patients with extra-axillary locoregional lymph node metastases exclusively detected by FDG-PET/CT was evaluated. For axillary lymph node metastases histopathology served as the reference standard. RESULTS: The sensitivity, specificity, PPV, NPV, and accuracy of FDG-PET/CT for the detection of axillary lymph node metastases were 54%, 89%, 77%, 74%, and 75%, respectively. For ultrasound it was 38%, 78%, 54%, 65%, and 62%, respectively. FDG-PET/CT was significantly more accurate than ultrasound for the detection of axillary lymph node metastases (P = 0.019). There was no statistically significant difference between the sensitivity of both modalities (P = 0.0578). FDG-PET/CT detected extra-axillary locoregional lymph node metastases in seven patients (8%) that had not been detected by another imaging modality. CONCLUSION: Though more accurate compared to ultrasound for evaluating the axillary lymph node status FDG-PET/CT is only as sensitive as ultrasound when it comes to the detection of axillary lymph node metastases. Due to the low sensitivity FDG-PET/CT cannot act as a substitute for Sentinel lymph node biopsy. FDG-PET/CT is able to detect previously unknown locoregional extra-axillary lymph node metastases.

Quantitative assessment of bone defect healing by multidetector CT in a pig model.

OBJECTIVE: To evaluate multidetector CT volumetry in the assessment of bone defect healing in comparison to histopathological findings in an animal model. MATERIALS AND METHODS: In 16 mini-pigs, a circumscribed tibial bone defect was created. Multidetector CT (MDCT) of the tibia was performed on a 64-row scanner 42 days after the operation. The extent of bone healing was estimated quantitatively by MDCT volumetry using a commercially available software programme (syngo Volume, Siemens, Germany).The volume of the entire defect (including all pixels from -100 to 3,000 HU), the nonconsolidated areas (-100 to 500 HU), and areas of osseous consolidation (500 to 3,000 HU) were assessed and the extent of consolidation was calculated. Histomorphometry served as the reference standard. RESULTS: The extent of osseous consolidation in MDCT volumetry ranged from 19 to 92% (mean 65.4 ± 18.5%). There was a significant correlation between histologically visible newly formed bone and the extent of osseous consolidation on MDCT volumetry (r = 0.82, P < 0.0001). A significant negative correlation was detected between osseous consolidation on MDCT and histological areas of persisting defect (r = -0.9, P < 0.0001). CONCLUSION: MDCT volumetry is a promising tool for noninvasive monitoring of bone healing, showing excellent correlation with histomorphometry.

Cone beam CT in assessment of tibial bone defect healing: an animal study.

RATIONALE AND OBJECTIVES: To evaluate cone beam computed tomography (CBCT) for monitoring of tibial bone defect healing in comparison to histopathological findings. MATERIALS AND METHODS: Circumscribed tibial bone defects were created in 16 mini-pigs and imaging of the tibia was performed on day 42 using a modern CBCT scanner with flat panel detector (PaX-Duo3D, Vatech, Korea). The extent of osseous consolidation including remaining calcium phosphate granules was measured quantitatively by a CBCT volumetry tool using commercially available software (Osirix Imaging software, Pixmeo, Geneva, Switzerland). Volumes of the entire defect (including all pixels), areas of osseous consolidation (density values >2350) and nonmineralized areas (density values <2350) of the defect were determined. The extent of bone regeneration was determined and correlated with the histomorphometrical reference standard. Independently, a visual semiquantitative CBCT-score was applied (4-point scale) to assess bone defect healing. RESULTS: The extent of osseous consolidation in CBCT volumetry ranged from 14% to 92% (mean, 63.4 ± 17.6%). There was a significant positive correlation between histologically visible newly formed bone and the extent of bone regeneration on CBCT volumetry (r = 0.74-0.79, P < .001). The visual score matched with the volumetric results in 75% of the cases. CONCLUSION: CBCT volumetry allows for reliable, noninvasive quantitative monitoring of bone defect healing and correlates significantly with histological findings. CBCT is a promising technique for imaging of peripheral bones suggesting further evaluation in clinical trials.

Diagnostic accuracy of virtual 18F-FDG PET/CT bronchoscopy for the detection of lymph node metastases in non-small cell lung cancer patients.

UNLABELLED: The aim of this study was to determine the diagnostic accuracy of (18)F-FDG PET/CT bronchoscopy for the detection of regional lymph node metastases in non-small cell lung cancer (NSCLC) patients; potential differences in the maximum standardized uptake value (SUVmax), mean SUV (SUVmean), short-axis diameter, and distance to the airways when comparing true-positive (TP), false-positive (FP), true-negative (TN), and false-negative (FN) lymph nodes; the smallest bronchus diameter accessible by virtual bronchoscopy; and the duration from the start of the virtual (18)F-FDG PET/CT bronchoscopy viewing tool until the images were displayed. METHODS: Sixty-one consecutive NSCLC patients (mean age ± SD, 58 ± 10 y) underwent whole-body (18)F-FDG PET/CT. From these data, virtual (18)F-FDG PET/CT bronchoscopies were reconstructed. The duration from the start of the tool until the display of virtual bronchoscopy images was determined. The diagnostic accuracy of (18)F-FDG PET/CT bronchoscopy for the detection of regional lymph node metastases was evaluated on a lesion basis. Axial (18)F-FDG PET/CT scans served as the standard of reference. The SUVmax, SUVmean, short-axis diameter, and distance to the airways of regional lymph nodes were measured. Lymph nodes were classified as TP, FP, TN, and FN. The smallest bronchus diameter accessible by (18)F-FDG PET/CT bronchoscopy was measured. RESULTS: The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of virtual (18)F-FDG PET/CT bronchoscopy for the detection of lymph node metastases were 76%, 87%, 85%, 79%, and 81%, respectively. The differences between the SUVmax, SUVmean, short-axis diameter, and distance to the airways of TP and FP as well as TN and FN lymph nodes were statistically significant (P < 0.05). The mean smallest diameter of accessible bronchi by (18)F-FDG PET/CT bronchoscopy was 3 mm. The mean time duration from the start of the virtual (18)F-FDG PET/CT bronchoscopy tool until the display of the images was 22 ± 7 s. CONCLUSION: Virtual fly-through 3-dimensional (18)F-FDG PET/CT bronchoscopy yields a high diagnostic accuracy for the detection of regional lymph node metastases and has access to bronchi even in the periphery of the lung. High SUVmax, high SUVmean, large small-axis diameter, and short distance to the airways aid detection of lymph node metastases with (18)F-FDG PET/CT bronchoscopy.