Bone texture analysis using CT-simulation scans to individuate risk parameters for radiation-induced insufficiency fractures

This study deals with the role of texture analysis as a predictive factor of radiation-induced insufficiency fractures in patients undergoing pelvic radiation.

INTRODUCTION

This study aims to assess the texture analysis (TA) of computed tomography (CT) simulation scans as a predictive factor of insufficiency fractures (IFs) in patients with pelvic malignancies undergoing radiation therapy (RT).

METHODS

We performed an analysis of patients undergoing pelvic RT from January 2010 to December 2014, 24 of whom had developed pelvic bone IFs. We analyzed CT-simulation images using ImageJ macro software and selected two regions of interest (ROIs), which are L5 body and the femoral head. TA parameters included mean (m), standard deviation (SD), skewness (sk), kurtosis (k), entropy (e), and uniformity (u). The IFs patients were compared (1:2 ratio) with controlled patients who had not developed IFs and matched for sex, age, menopausal status, type of tumor, use of chemotherapy, and RT dose. A reliability test of intra- and inter-reader ROI TA reproducibility with the intra-class correlation coefficient (ICC) was performed. Univariate and multivariate analyses (logistic regression) were applied for TA parameters observed both in the IFs and the controlled groups.

RESULTS

Inter- and intra-reader ROI TA was highly reproducible (ICC > 0.90). Significant TA parameters on paired t test included L5 m (p = 0.001), SD (p = 0.002), k (p = 0.006), e (p = 0.004), and u (p = 0.015) and femoral head m (p < 0.001) and SD (p = 0.001), whereas on logistic regression analysis, L5 e (p = 0.003) and u (p = 0.010) and femoral head m (p = 0.027), SD (p = 0.015), and sex (p = 0.044).

CONCLUSIONS

In our experience, bone CT TA could be correlated to the risk of radiation-induced IFs. Studies on a large patient series and methodological refinements are warranted.

Impact of molecular subtypes classification concordance between preoperative core needle biopsy and surgical specimen on early breast cancer management: Single-institution experience and review of published literature

BACKGROUND

Core needle biopsy (CNB) plays a crucial role as diagnostic tool for breast cancer (BC). The characterization of biomarkers status before surgical treatment is crucial when primary systemic therapy is a therapeutic option. The aim of this analysis was to report concordance between preoperative CNB and surgical specimen (SS) in evaluating biomarkers and molecular subtypes.

METHODS

Data have been collected from a cohort of 101 patients affected by early BC treated at Careggi Florence University Hospital, between January 2014 and March 2015. The conformity between molecular subtype classification was tested using kappa (κ) test.

RESULTS

Mean age was 57.5 years (range 29-86). There was concordance between the estrogen receptor (ER) assessment on CNB and SS in 95 cases (94.1%). Concordance of the progesterone receptor (PgR) assessment was observed in 89 cases (88.1%). Concordance for detecting immunohistochemistry-assessed BC molecular subtypes was 87.1% (κ = 0.78). Concerning Ki-67 evaluation, we report a concordance rate of 88.1% (κ = 0.68). The evaluation of luminal A plus luminal B/HER negative subgroup showed a κ-value of 0.65.

CONCLUSIONS

CNB showed good accuracy in evaluating hormonal receptors status, HER2, and BC molecular subtypes. Evaluation of Ki67 status was less accurate than other biomarkers; therefore, we recommend that it should be detected both on CNB and SS samples, especially in hormonal positive HER2 negative tumors, in order to avoid a misclassification of tumor subtypes that could lead to an omission of potential effective systemic therapy.

Water/cortical bone decomposition: A new approach in dual energy CT imaging for bone marrow oedema detection. A feasibility study

INTRODUCTION

Many studies aimed at validating the application of Dual Energy Computed Tomography (DECT) in clinical practice where conventional CT is not exhaustive. An example is given by bone marrow oedema detection, in which DECT based on water/calcium (W/Ca) decomposition was applied. In this paper a new DECT approach, based on water/cortical bone (W/CB) decomposition, was investigated.

MATERIALS AND METHODS

Eight patients suffering from marrow oedema were scanned with MRI and DECT. Two-materials density decomposition was performed in ROIs corresponding to normal bone marrow and oedema. These regions were drawn on DECT images using MRI informations. Both W/Ca and W/CB were considered as material basis. Scatter plots of W/Ca and W/CB concentrations were made for each ROI in order to evaluate if oedema could be distinguished from normal bone marrow. Thresholds were defined on the scatter plots in order to produce DECT images where oedema regions were highlighted through color maps. The agreement between these images and MR was scored by two expert radiologists.

RESULTS

For all the patients, the best scores were obtained using W/CB density decomposition.

CONCLUSIONS

In all cases, DECT color map images based on W/CB decomposition showed better agreement with MR in bone marrow oedema identification with respect to W/Ca decomposition. This result encourages further studies in order to evaluate if DECT based on W/CB decomposition could be an alternative technique to MR, which would be important when short scanning duration is relevant, as in the case of aged or traumatic patients.

Prognostic Value of MR Imaging Texture Analysis in Brain Non-Small Cell Lung Cancer Oligo-Metastases Undergoing Stereotactic Irradiation

BACKGROUND : Stereotactic irradiation is widely used in brain oligo-metastases treatment. The aim of this study is to evaluate the prognostic value of magnetic resonance imaging (MRI) texture analysis (TA) of brain metastases (BM) of non-small cell lung cancer (NSCLC). MATERIALS AND METHODS : This study included thirty-eight consecutive patients undergoing stereotactic irradiation, that is, stereotactic fractionated radiotherapy (SRT) or radiosurgery (SRS), from January 2011 to December 2014 for 1-2 brain BM from NSCLC. Whole-brain radiotherapy (WBRT) was not delivered. The diagnostic MRI DICOM (Digital Imaging and Communications in Medicine) images were collected and analyzed with a homemade ImageJ macro, and typical TA parameters (mean, standard deviation, skewness, kurtosis, entropy, and uniformity) were evaluated for: brain progression-free survival; modality of brain metastatic progression (local progression or/and new metastases); and overall survival, after SRT/SRS.

RESULTS

After SRT/SRS 14 patients (36.8%) experienced recurrence in the brain, with a recurrence in the irradiated site (five patients, 13.2%), new metastases (11 patients, 28.9%), local recurrence and new metastases (two patients, 5.25%). Nineteen patients (50%) died of tumor progression or other causes. Entropy and uniformity were significantly associated with local progression, whereas kurtosis was significantly associated with both local progression and new brain metastases. CONCLUSIONS : These results appear promising, since the knowledge of factors correlated with the modality of brain progression after stereotactic irradiation of brain oligo-metastatic foci of NSCLC might help in driving the best treatment in these patients (association of SRT/SRS with WBRT? Increase of SRT/SRS dose?). Our preliminary data needs confirmation in large patient series.

A PPAR-gamma agonist attenuates pulmonary injury induced by irradiation in a murine model

PURPOSE/OBJECTIVE(S)

Due to its anti-inflammatory, antifibrotic and antineoplastic properties, the PPAR-γ agonist rosiglitazone is of interest in the prevention and therapy of radiation-induced pulmonary injury. We evaluated the radioprotective effects of rosiglitazone in a murine model of pulmonary damage to determine whether radioprotection was selective for normal and tumor tissues.

METHODS

Lungs in C57BL/6J mice were irradiated (19 Gy) with or without rosiglitazone (RGZ, 5mg/kg/day for 16 weeks, oral gavage). Computed tomography (CT) was performed and Hounsfield Units (HU) were determined during the observation period. Histological analysis and evaluation of fibrosis/inflammatory markers by western blot were performed at 16 weeks. A549 tumor-bearing CD1 mice were irradiated (16 Gy) with or without RGZ, and tumor volumes were measured at 35 days.

RESULTS

Rosiglitazone reduced radiologic and histologic signs of fibrosis, inflammatory infiltrate, alterations to alveolar structures, and HU lung density that was increased due to irradiation. RGZ treatment also significantly decreased Col1, NF-kB and TGF-β expression and increased Bcl-2 protein expression compared to the irradiation group and reduced A549 clonogenic survival and xenograft tumor growth.

CONCLUSIONS

Rosiglitazone exerted a protective effect on normal tissues in radiation-induced pulmonary injury, while irradiated lung cancer cells were not protected in vivo and in vitro. Thus, rosiglitazone could be proposed as a radioprotective agent in the treatment of lung cancer.

Surface imaging, portal imaging, and skin marker set-up vs. CBCT for radiotherapy of the thorax and pelvis

AIM

The aim of this study was to compare surface imaging, portal imaging, and skin marker set-up in radiotherapy of thoracic and pelvic regions, using cone beam computed tomography (CBCT) data as the gold standard.

PATIENTS AND METHODS

Twenty patients were included in this study. CBCT, surface acquisition (SA), and two orthogonal portal images (PI) were acquired during the first four treatment sessions. Patient set-up corrections, obtained by registering the planning CT with CBCT, were used as the gold standard. Registration results of the PI and SA were evaluated and compared with those obtained with CBCT. The advantage derived from using SA or PI verification systems over a skin marker set-up was also quantified.

RESULTS

A statistically significant difference between PI and SA (in favour of PI) was observed in seven patients undergoing treatment of the pelvic region and in two patients undergoing treatment of the thoracic region. The use of SA or PI, compared with a skin marker set-up, improved patient positioning in 50% and 57% of the thoracic fractions, respectively. For pelvic fractions, the use of PI was beneficial in 73% of the cases, while the use of SA was beneficial in only 45%. Patient positioning worsened with SA, particularly along longitudinal and vertical directions.

CONCLUSION

PI yielded more accurate registration results than SA for both pelvic and thoracic fractions. Compared with the skin marker set-up, PI performances were superior to SA for pelvic fractions while comparable results were obtained for thoracic fractions.

Phyllodes tumours of the breast diagnosed as B3 category on image-guided 14-gauge core biopsy: analysis of 51 cases from a single institution and review of the literature

AIMS

Image-guided 14-gauge (G) core biopsy (CB) has been shown to be an accurate method providing histological diagnosis of breast lesions. The purpose of this study was to evaluate the reliability of image-guided 14-G CB in the diagnosis of phyllodes tumours (PT) reported as B3 category and its accuracy in distinguishing this lesion from fibroadenomas (FA).

MATERIALS AND METHODS

The records of 10 000 image-guided 14-G CB of the breast performed from January 2001 to August 2011 at the Diagnostic Senology Unit of Careggi University Hospital were reviewed; 2554 (25.5%) were fibroepithelial lesions: 56 of them (2%) were diagnosed as PT and reported as B3 category. The database of the Pathological Anatomy Unit of Careggi University Hospital was then searched to verify the histological diagnosis after surgical excision. Fifty-one cases of PT diagnosed as B3 category in 51 women were included in the present study.

RESULTS

Of the 51 cases of PT diagnosed as B3 category on 14-G CB, 39 (76.5%) lesions were confirmed as PT on SE (30, 4 and 5 as benign, borderline and malignant PT respectively) with a PPV of 76.5%. Twelve lesions (23.5%) were diagnosed as FA after surgical excision.

CONCLUSIONS

Our study shows that 14-G CB is a valuable tool, in a preoperative setting, in diagnosing PT.

Alternative normalization methods demonstrate widespread cortical hypometabolism in untreated de novo Parkinson's disease

AIM

Previous positron emission tomography (PET) [18F]fluorodeoxyglucose ([18F]FDG) studies in Parkinson's disease (PD) demonstrated that moderate to late stage patients display widespread cortical hypometabolism, whereas early stage PD patients exhibit little or no cortical changes. However, recent studies suggested that conventional data normalization procedures may not always be valid, and demonstrated that alternative normalization strategies better allow detection of low magnitude changes. We hypothesized that these alternative normalization procedures would disclose more widespread metabolic alterations in de novo PD.

METHODS

[18F]FDG PET scans of 26 untreated de novo PD patients (Hoehn & Yahr stage I-II) and 21 age-matched controls were compared using voxel-based analysis. Normalization was performed using gray matter (GM), white matter (WM) reference regions and Yakushev normalization.

RESULTS

Compared to GM normalization, WM and Yakushev normalization procedures disclosed much larger cortical regions of relative hypometabolism in the PD group with extensive involvement of frontal and parieto-temporal-occipital cortices, and several subcortical structures. Furthermore, in the WM and Yakushev normalized analyses, stage II patients displayed more prominent cortical hypometabolism than did stage I patients.

CONCLUSION

The use of alternative normalization procedures, other than GM, suggests that much more extensive cortical hypometabolism is present in untreated de novo PD patients than hitherto reported. The finding may have implications for our understanding of the basic pathophysiology of early-stage PD.

¹²⁵I-radiolabeled morpholine-containing arginine-glycine-aspartate (RGD) ligand of αvβ₃ integrin as a molecular imaging probe for angiogenesis

In this paper, using a hybrid small-animal Micro SPECT/CT imaging system, we report that a new (125)I-Cilengitide-like RGD-cyclopentapeptide, containing d-morpholine-3-carboxylic acid, interacts in vivo with α(v)β(3) integrin expressed by melanoma cells. Images clearly show that the (125)I-compound has the capacity to monitor the growth of a melanoma xenograft. Indeed, retention of the labeled ligand in the tumor mass has a good tumor/background ratio, and a significant reduction of its uptake was observed after injection of unlabeled ligand. These results suggest that the use of (125)I-labeled morpholine-based RGD-cyclopentapeptides targeting α(v)β(3) positive tumors may play a role in future therapeutic strategies.

Radial scar without associated atypical epithelial proliferation on image-guided 14-gauge needle core biopsy: analysis of 49 cases from a single-centre and review of the literature

The purpose of this study was to evaluate the reliability of image-guided 14-gauge needle core biopsy in the diagnosis of radial scar without associated atypical epithelial proliferation, by comparison with definitive histological diagnosis on surgical excision. The records of 8792 consecutive image-guided 14-gauge needle core biopsy of the breast performed from January 1996 to December 2009 were reviewed. Forty-nine cases of radial scar without associated atypical epithelial proliferation were identified and compared with definitive histological diagnosis on surgical excision. The definitive histological diagnosis on surgical excision confirmed the results of image-guided 14-gauge needle core biopsy in 36 of 49 cases (73.5%), in 9 cases (18.3%) radial scar was associated with atypical epithelial proliferation, while 4 cases out of 49 cases were upgraded to carcinoma (3 cases of ductal carcinoma in situ and one case of invasive lobular carcinoma), with an underestimation rate of 8.2%. A diagnosis of radial scar without associated atypical epithelial proliferation on image-guided 14-gauge needle core biopsy does not exclude a malignancy on surgical excision; consequently during the multidisciplinary discussion further assessment by surgical excision or vacuum-assisted excision, as recently reported, needs to be considered to obtain a definitive histological diagnosis.

Evaluation of a method for activity estimation in Sm-153 EDTMP imaging

Absolute activity evaluation is fundamental for internal radionuclide dosimetry when patient-specific therapy optimization is wanted. Often, quantification is attempted with 3D SPECT image based (IB) methods, but the true concentration values can be underestimated due to the partial volume effect (PVE). This is especially true when small diffuse lesions are present. In this paper, we describe a 3D region of interest (ROI) based quantification method (LS-ROI), which estimates the ROI concentration values directly from the projection data acquired in the tomographic scan once ROIs have been segmented on a CT and/or a SPECT image. The method, which has inherent PVE correction capabilities, was applied both on simulated and on real phantom data. Simulations reflected the case of a patient with bone metastases treated with 153Sm-EDTMP: Both the activity in the metastases and the total retention in the skeleton were evaluated. Thirty noisy data sets were produced in order to evaluate the accuracy and precision of the method. The effect of region segmentation errors on estimated concentrations was thoroughly investigated. Real data were acquired on a NEMA phantom, where a cylindrical central region (283 cm3) simulated the bone and two spheres (10.3 and 25.5 cm3) simulated the metastases. The results obtained with the LS-ROI method were compared with those of a conventional 3D IB method and those of a quantitative conjugate view approach derived from LS-ROI and applied to the anterior and posterior views acquired in the tomographic scan (LS-ROI anterior-posterior: LS-ROI-AP). Simulations showed that when the geometry of regions is known, the LS-ROI method recovered the simulated concentration values within 20%, while the IB method underestimated the concentration in high activity small lesions by as much as 49%. Segmentation errors, up to 44% of the true region volume, produced a higher variation in LS-ROI estimates than in IB ones; however, the overall bias of the LS-ROI estimates (< or = 25%) remained lower than that of IB estimates. In the case of the evaluation of the total retention in the skeleton, the LS-ROI method recovered the simulated value within 2%, while IB underestimated it up to 13%. In all the cases, the LS-ROI-AP method showed an accuracy comparable with that of the LS-ROI one, and a worse precision just because of the lower number of counts used in the analysis. However, a worsening of LS-ROI-AP performances was demonstrated in the case of strong overlap of regions: In this case, a bias of up to 40% was observed. The results obtained on real phantom data confirmed the simulation results: The IB method underestimated activity up to 47% in the smallest sphere, while the bias was reduced to 13% with LS-ROI and LS-ROI-AP estimates. The good quantification capabilities of the LS-ROI method can be useful for absolute activity quantification in the case of small active diffused lesions and constitute the basis for the development of an accurate patient-specific planning strategy in internal radionuclide treatments, provided there is a reliable segmentation of lesions.

A direct ROI quantification method for inherent PVE correction: accuracy assessment in striatal SPECT measurements

PURPOSE

The clinical potential of striatal imaging with dopamine transporter (DAT) SPECT tracers is hampered by the limited capability to recover activity concentration ratios due to partial volume effects (PVE). We evaluated the accuracy of a least squares method that allows retrieval of activity in regions of interest directly from projections (LS-ROI).

METHODS

An Alderson striatal phantom was filled with striatal to background ratios of 6:1, 9:1 and 28:1; the striatal and background ROIs were drawn on a coregistered X-ray CT of the phantom. The activity ratios of these ROIs were derived both with the LS-ROI method and with conventional SPECT EM reconstruction (EM-SPECT). Moreover, the two methods were compared in seven patients with motor symptoms who were examined with N-3-fluoropropyl-2-beta-carboxymethoxy-3-beta-(4-iodophenyl) (FP-CIT) SPECT, calculating the binding potential (BP).

RESULTS

In the phantom study, the activity ratios obtained with EM-SPECT were 3.5, 5.3 and 17.0, respectively, whereas the LS-ROI method resulted in ratios of 6.2, 9.0 and 27.3, respectively. With the LS-ROI method, the BP in the seven patients was approximately 60% higher than with EM-SPECT; a linear correlation between the LS-ROI and the EM estimates was found (r=0.98, p=0.03).

CONCLUSION

The LS-ROI PVE correction capability is mainly due to the fact that the ill-conditioning of the LS-ROI approach is lower than that of the EM-SPECT one. The LS-ROI seems to be feasible and accurate in the examination of the dopaminergic system. This approach can be fruitful in monitoring of disease progression and in clinical trials of dopaminergic drugs.

Energetics of midvelocity emissions in peripheral heavy ion collisions at Fermi energies

Peripheral and semiperipheral collisions have been studied in the system 93Nb+93Nb at 38A MeV. The evaporative and midvelocity components of the light charged particle and intermediate mass fragment emissions have been carefully disentangled. In this way it was possible to obtain the average amount not only of charge and mass, but also of energy, pertaining to the midvelocity emission, as a function of an impact parameter estimator. This emission has a very important role in the overall balance of the reaction, as it accounts for a large fraction of the emitted mass and for more than half of the dissipated energy. As such, it may give precious clues on the microscopic mechanism of energy transport from the interaction zone toward the target and projectile remnants.

Kinetic parameter estimation from renal measurements with a three-headed SPECT system: a simulation study

We present here a direct least-squares estimation (DLSE) method for the determination of renal kinetic parameters from sequences of very fast acquisitions performed with a three-headed single photon emission computed tomography (SPECT) system. A simple linear model for the behavior of the radiopharmaceutical, as well as a spatial model for its spatial distribution are defined. The model enables one to estimate the kinetic parameters directly from the projections, once the plasma concentration function is known. A new technique for the accurate reconstruction of time-radioactivity curves based on the direct reconstruction of the region-of-interest contents from a series of data from three-projections is presented. The technique is used to determine the plasma concentration function with a sub-second time resolution. The spatially-variant geometrical response is also included in the model to compensate for the spatial resolution of the SPECT system. Results obtained from simulations are presented. Basic spatial and time features of the simulations are derived from a patient study. Noise and segmentation errors are also simulated. The DLSE method is compared with the conventional one of deriving kinetic parameters from the time series of reconstructed images. The standard deviation of results given by DLSE is less than 2%, whereas with the conventional method it is between 5% and 6%. Within the limit of statistical fluctuations, DLSE results are unbiased whereas those of the conventional method are overestimated by 24%.

Ultrasonographic study on the growth and dimensions of healthy children and adults organs

We measured by ultrasound the spleen, the kidneys, the pancreas in 323 children (age 0-12), the thyroid in 60 children of same age range, and all these organs in 180 adults (in adults we measured additionally the testis, the gallbladder and the choledochus). Children and adults were all healthy, without evidence of pathologies potentially involving these organs. The children have been selected looking at clinical and hematological parameters, while the adults have been selected among a military population, that is the most significant sample of healthy young adults. We measured the length, the transversal diameter and the thickness of the spleen, kidneys, pancreas, testis and thyroid, the diameter of the choledochus and the maximum length of the gallbladder (pre and post stimulus). We found a good correlation between age and dimensions for pancreas, kidneys and spleen in children, representing the progressive growth of these organs. Our data represent an assessment of the normal dimensions of these organs in vivo by means of ultrasound, and therefore they are an useful tool to discriminate pathologically enlarged or reduced organs, both in children and in adults.

Predicting ovarian malignancy: application of artificial neural networks to transvaginal and color Doppler flow US

PURPOSE

To compare the performance of artificial neural networks (ANNs) with that of multiple logistic regression (MLR) models for predicting ovarian malignancy in patients with adnexal masses by using transvaginal B-mode and color Doppler flow ultrasonography (US).

MATERIALS AND METHODS

A total of 226 adnexal masses were examined before surgery: Fifty-one were malignant and 175 were benign. The data were divided into training and testing subsets by using a "leave n out method." The training subsets were used to compute the optimum MLR equations and to train the ANNs. The cross-validation subsets were used to estimate the performance of each of the two models in predicting ovarian malignancy.

RESULTS

At testing, three-layer back-propagation networks, based on the same input variables selected by using MLR (i.e., women's ages, papillary projections, random echogenicity, peak systolic velocity, and resistance index), had a significantly higher sensitivity than did MLR (96% vs 84%; McNemar test, p = .04). The Brier scores for ANNs were significantly lower than those calculated for MLR (Student t test for paired samples, P = .004).

CONCLUSION

ANNs might have potential for categorizing adnexal masses as either malignant or benign on the basis of multiple variables related to demographic and US features.

First trimester screening for Down's syndrome using maternal serum PAPP-A and free beta-hCG in combination with fetal nuchal translucency thickness

The aim of this study was to evaluate the potential effectiveness of maternal serum pregnancy-associated plasma protein A (PAPP-A) and free beta-hCG in combination with nuchal translucency thickness in first trimester screening for Down's syndrome. Maternal serum levels of PAPP-A and free beta-hCG were assayed in stored sera from 32 Down's syndrome and 200 unaffected pregnancies. Fetal nuchal translucency was measured by ultrasound at the time of blood sampling. Screening of Down's syndrome using a combination of maternal age, PAPP-A, free beta-hCG and nuchal translucency would achieve a detection rate of 75.8% for a false positive rate of 5%.

Comparison between two methods of standardization for gestational age differences in fetal nuchal translucency measurement in first-trimester screening for trisomy 21

Our purpose was to compare two different methods of expressing nuchal translucency (NT) measurements in first-trimester screening for trisomy 21: the difference in millimeters from the median of nuchal translucency (delta value: delta NT) and the multiple of the expected median (MoM). Fetal nuchal translucency was measured in 32 fetuses with trisomy 21 and in 3180 normal fetuses at 9-13 weeks' gestation. For each fetus, the measured nuchal translucency was expressed both as a delta value and MoM. The effectiveness of the MoM-Gaussian vs. the delta value method in modifying the age-specific risk for trisomy 21 was compared by using both the maternal age distribution of our study population and the age distribution of a general obstetric population. The use of the MoM-Gaussian approach led to a reduction in the false-positive rate at a given detection rate, both in the study population (by 1.2-15.2%) and in the general population (by 0.4-2.4%). Our results suggest that the use of the MoM-Gaussian method might confer a potential advantage on the screening performance of nuchal translucency in combination with maternal age by decreasing the false-positive rate. Further studies in larger unselected populations will be needed to confirm the effectiveness of this approach.