Rapid volumetric photoacoustic tomographic imaging with a Fabry-Perot ultrasound sensor depicts peripheral arteries and microvascular vasomotor responses to thermal stimuli

Purpose

To determine if a new photoacoustic imaging (PAI) system successfully depicts (1) peripheral arteries and (2) microvascular circulatory changes in response to thermal stimuli.

Methods

Following ethical permission, 8 consenting subjects underwent PAI of the dorsalis pedis (DP) artery, and 13 completed PAI of the index fingertip. Finger images were obtained after immersion in warm (30-35 °C) or cold (10-15 °C) water to promote vasodilation or vasoconstriction. The PAI instrument used a Fabry-Perot interferometeric ultrasound sensor and a 30-Hz 750-nm pulsed excitation laser. Volumetric images were acquired through a 14 × 14 × 14-mm volume over 90 s. Images were evaluated subjectively and quantitatively to determine if PAI could depict cold-induced vasoconstriction. The full width at half maximum (FWHM) of resolvable vessels was measured.

Results

Fingertip vessels were visible in all participants, with mean FWHM of 125 μm. Two radiologists used PAI to correctly identify vasoconstricted fingertip capillary beds with 100% accuracy (95% CI 77.2-100.0%, p < 0.001). The number of voxels exhibiting vascular signal was significantly smaller after cold water immersion (cold: 5263 voxels; warm: 363,470 voxels, p < 0.001). The DP artery was visible in 7/8 participants (87.5%).

Conclusion

PAI achieves rapid, volumetric, high-resolution imaging of peripheral limb vessels and the microvasculature and is responsive to vasomotor changes induced by thermal stimuli.

Key points

? Fabry-Perot interferometer-based photoacoustic imaging (PAI) generates volumetric, high-resolution images of the peripheral vasculature. ? The system reliably detects thermally induced peripheral vasoconstriction (100% correct identification rate, p < 0.001). ? Vessels measuring less than 100 μm in diameter can be depicted in vivo.

     

Classification of forensically-relevant larvae according to instar in a closely related species of carrion beetles (Coleoptera: Silphidae: Silphinae)

Carrion beetle larvae of Necrodes littoralis (Linnaeus, 1758), Oiceoptoma thoracicum (Linnaeus, 1758), Thanatophilus sinuatus (Fabricius, 1775), and Thanatophilus rugosus (Linnaeus, 1758) (Silphidae: Silphinae) were studied to test the concept that a classifier of the subfamily level may be successfully used to classify larvae according to instar. Classifiers were created and validated using a linear discriminant analysis (LDA). LDA generates classification functions which are used to calculate classification values for tested specimens. The largest value indicates the larval instar to which the specimen should be assigned. Distance between dorsal stemmata and width of the pronotum were used as classification features. The classifier correctly classified larvae of N. littoralis and O. thoracicum, whereas in the case of T. sinuatus and T. rugosus a few misclassifications were recorded. For this reason, a separate genus level classifier was created for larvae of Thanatophilus. We conclude that larval instar classifiers of the subfamily or genus level have very high classification accuracy and therefore they may be safely used to classify carrion beetle larvae according to instar in forensic practice.     

Temperature-dependent appearance of forensically useful flies on carcasses

Flies are frequently used for postmortem interval (PMI) estimations. These estimates are usually based on the age of larval or pupal specimens. However, the age defines only the minimum PMI. In order to move forensic entomology further, a method useful for the estimation of an interval preceding insect appearance on a corpse called the pre-appearance interval (PAI) is needed. Recently, it was demonstrated that the PAI of several carrion beetles is closely related to the temperature prevailing throughout this interval. Hence, it was postulated to estimate PAI from temperature. In order to check premises for using this approach with flies, a test of the relationship between adult or oviposition PAI and temperature was made for nine species of European flies. Data on PAI originated from pig carcasses decomposing under various temperatures. Adult PAI of Hydrotaea dentipes, Hydrotaea ignava, Hydrotaea similis, Phormia regina, and Stearibia nigriceps and oviposition PAI of S. nigriceps were exponentially related to temperature. Only S. nigriceps revealed a close relationship, demonstrating solid premises for PAI estimation from temperature alone. Adult and oviposition PAI of Calliphora vomitoria and adult PAI of Hydrotaea pilipes were not related to temperature. Adult and oviposition PAI of Lucilia sericata and Lucilia caesar responded similarly, with an abrupt and large increase in a narrow range of low temperatures and no response in a broad range of high temperatures. Probably, different mechanisms form the basis for the response of PAI to temperature in flies colonizing carcasses shortly after death and flies colonizing carcasses later in the decomposition process.     

Prognostic implications of the co-detection of the urokinase plasminogen activator system and osteopontin in patients with non-small-cell lung cancer undergoing radiotherapy and correlation with gross tumor volume

Background

The urokinase plasminogen activator system (uPA, uPAR, PAI?1) is upregulated in cancer and high plasma levels are associated with poor prognosis. Their interaction with hypoxia-related osteopontin (OPN) which is also overexpressed in malignant tumors suggests potential clinical relevance. However, the prognostic role of the uPA system in the radiotherapy (RT) of non-small-cell lung cancer (NSCLC), particularly in combination with OPN, has not been investigated so far.

Methods

uPA, uPAR, PAI?1 and OPN plasma levels of 81 patients with locally advanced or metastasized NSCLC were prospectively analyzed by ELISA before RT and were correlated to clinical patient/tumor data and prognosis after RT.

Results

uPAR plasma levels were higher in M1; uPA and PAI?1 levels were higher in M0 NSCLC patients. uPAR correlated with uPA (p?<?0.001) which also correlated with PAI?1 (p?<?0.001). The prognostic impact of OPN plasma levels in the RT of NSCLC was previously reported by our group. PAI?I plasma levels significantly impacted overall (OS) and progression-free survival (PFS). Low PAI?1 levels were associated with a significantly reduced OS and PFS with a nearly 2?fold increased risk of death (p?=?0.029) and tumor progression (p?=?0.029). In multivariate analysis, PAI?1 levels remained an independent prognostic factor for OS and PFS with a 3?fold increased risk of death (p?=?0.001). If PAI?1 plasma levels were combined with OPN or tumor volume, we found an additive prognostic impact on OS and PFS with a 2.5- to 3?fold increased risk of death (p?=?0.01).

Conclusion

Our results suggest that PAI-1 but not uPA and uPAR might add prognostic information in patients with advanced NSCLC undergoing RT. High pretreatment PAI-1 plasma levels were found predominantly in M0-stage patients and indicate a favorable prognosis as opposed to OPN where high plasma levels are associated with poor survival and metastasis. In combination, PAI-1 and OPN levels successfully predicted outcome and additively correlated with prognosis. These findings support the notion of an antidromic prognostic impact of OPN and PAI-1 plasma levels in the RT of advanced NSCLC.

     

Comparative evaluation of the algorithms for parametric mapping of the novel myocardial PET imaging agent <Superscript>18</Superscript>F-FPTP

Objective

(¹⁸F-fluoropentyl)triphenylphosphonium salt (¹⁸F-FPTP) is a new promising myocardial PET imaging tracer. It shows high accumulation in cardiomyocytes and rapid clearance from liver. We performed compartmental analysis of ¹⁸F-FPTP PET images in rat and evaluated two linear analyses: linear least-squares (LLS) and a basis function method (BFM) for generating parametric images. The minimum dynamic scan duration for kinetic analysis was also investigated and computer simulation undertaken.

Methods

¹⁸F-FPTP dynamic PET (18 min) and CT images were acquired from rats with myocardial infarction (MI) (n = 12). Regions of interest (ROIs) were on the left ventricle, normal myocardium, and MI region. Two-compartment (K ₁ and k ₂; 2C2P) and three-compartment (K ₁–k ₃; 3C3P) models with irreversible uptake were compared for goodness-of-fit. Partial volume and spillover correction terms (V _a and α = 1 ? V _a ) were also incorporated. LLS and BFM were applied to ROI- and voxel-based kinetic parameter estimations. Results were compared with the standard ROI-based nonlinear least-squares (NLS) results of the corresponding compartment model. A simulation explored statistical properties of the estimation methods.

Results

The 2C2P model was most suitable for describing ¹⁸F-FPTP kinetics. Average K ₁, k ₂, and V _a values were, respectively, 6.8 (ml/min/g), 1.1 (min^?1), and 0.44 in normal myocardium and 1.4 (ml/min/g), 1.1 (min^?1), and 0.32, in MI tissue. Ten minutes of data was sufficient for the estimation. LLS and BFM estimations correlated well with NLS values for the ROI level (K ₁: y = 1.06x + 0.13, r ²  = 0.96 and y = 1.13x + 0.08, r ²  = 0.97) and voxel level (K ₁: y = 1.22x ? 0.30, r ²  = 0.90 and y = 1.26x + 0.00, r ²  = 0.92). Regional distribution of kinetic parametric images (αK ₁, K ₁, k ₂, V _a) was physiologically relevant. LLS and BFM showed more robust characteristics than NLS in the simulation.

Conclusions

Fast kinetics and highly specific uptake of ¹⁸F-FPTP by myocardium enabled quantitative analysis with the 2C2P model using only the initial 10 min of data. LLS and BFM were feasible for estimating voxel-wise parameters. These two methods will be useful for quantitative evaluation of ¹⁸F-FPTP distribution in myocardium and in further studies with different conditions, disease models, and species.

     

Abdominal fat volume estimation by stereology on CT: a comparison with manual planimetry

Objectives

To deploy and evaluate a stereological point-counting technique on abdominal CT for the estimation of visceral (VAF) and subcutaneous abdominal fat (SAF) volumes.

Methods

Stereological volume estimations based on point counting and systematic sampling were performed on images from 14 consecutive patients who had undergone abdominal CT. For the optimization of the method, five sampling intensities in combination with 100 and 200 points were tested. The optimum stereological measurements were compared with VAF and SAF volumes derived by the standard technique of manual planimetry on the same scans.

Results

Optimization analysis showed that the selection of 200 points along with the sampling intensity 1/8 provided efficient volume estimations in less than 4 min for VAF and SAF together. The optimized stereology showed strong correlation with planimetry (VAF: r?=?0.98; SAF: r?=?0.98). No statistical differences were found between the two methods (VAF: P?=?0.81; SAF: P?=?0.83). The 95 % limits of agreement were also acceptable (VAF: ?16.5 %, 16.1 %; SAF: ?10.8 %, 10.7 %) and the repeatability of stereology was good (VAF: CV?=?4.5 %, SAF: CV?=?3.2 %).

Conclusions

Stereology may be successfully applied to CT images for the efficient estimation of abdominal fat volume and may constitute a good alternative to the conventional planimetric technique.

Key Points:

? Abdominal obesity is associated with increased risk of disease and mortality. ? Stereology may quantify visceral and subcutaneous abdominal fat accurately and consistently. ? The application of stereology to estimating abdominal volume fat reduces processing time. ? Stereology is an efficient alternative method for estimating abdominal fat volume.

     

Contrast-enhanced 3T MR Perfusion of Musculoskeletal Tumours: T1 Value Heterogeneity Assessment and Evaluation of the Influence of T1 Estimation Methods on Quantitative Parameters

Objective

To evaluate intra-tumour and striated muscle T1 value heterogeneity and the influence of different methods of T1 estimation on the variability of quantitative perfusion parameters.

Material and methods

Eighty-two patients with a histologically confirmed musculoskeletal tumour were prospectively included in this study and, with ethics committee approval, underwent contrast-enhanced MR perfusion and T1 mapping. T1 value variations in viable tumour areas and in normal-appearing striated muscle were assessed. In 20 cases, normal muscle perfusion parameters were calculated using three different methods: signal based and gadolinium concentration based on fixed and variable T1 values.

Results

Tumour and normal muscle T1 values were significantly different (p?=?0.0008). T1 value heterogeneity was higher in tumours than in normal muscle (variation of 19.8% versus 13%). The T1 estimation method had a considerable influence on the variability of perfusion parameters. Fixed T1 values yielded higher coefficients of variation than variable T1 values (mean 109.6?±?41.8% and 58.3?±?14.1% respectively). Area under the curve was the least variable parameter (36%).

Conclusion

T1 values in musculoskeletal tumours are significantly different and more heterogeneous than normal muscle. Patient-specific T1 estimation is needed for direct inter-patient comparison of perfusion parameters.

Key Points

? T1 value variation in musculoskeletal tumours is considerable. ? T1 values in muscle and tumours are significantly different. ? Patient-specific T1 estimation is needed for comparison of inter-patient perfusion parameters. ? Technical variation is higher in permeability than semiquantitative perfusion parameters.

     

Dynamic contrast-enhanced MR imaging in predicting progression of enhancing lesions persisting after standard treatment in glioblastoma patients: a prospective study

Objectives

To prospectively explore the value of dynamic contrast-enhanced magnetic resonance imaging (DCE–MRI) in predicting the progression of enhancing lesions persisting after standard treatment in patients with surgically resected glioblastoma (GBM).

Methods

Forty-seven GBM patients, who underwent near-total tumorectomy followed by concurrent chemoradiation therapy (CCRT) with temozolomide (TMZ) between May 2014 and February 2016, were enrolled. Twenty-four patients were finally analyzed for measurable enhancing lesions persisting after standard treatment. DCE-MRI parameters were calculated at enhancing lesions. Mann–Whitney U tests and multivariable stepwise logistic regression were used to compare parameters between progression (n?=?16) and non-progression (n?=?8) groups.

Results

Mean K^trans and v_e were significantly lower in progression than in non-progression (P?=?0.037 and P?=?0.037, respectively). The 5th percentile of the cumulative K^trans histogram was also significantly lower in the progression than in non-progression group (P?=?0.017). Mean v_e was the only independent predictor of progression (P?=?0.007), with a sensitivity of 100%, specificity of 63%, and an overall accuracy of 88% at a cut-off value of 0.873.

Conclusions

DCE-MRI may help predict the progression of enhancing lesions persisting after the completion of standard treatment in patients with surgically resected GBM, with mean v_e serving as an independent predictor of progression.

Key points

? Enhancing lesions may persist after standard treatment in GBM patients.? DCE-MRI may help predict the progression of the enhancing lesions.? Mean K ^trans and v _e were lower in progression than in non-progression group.? DCE-MRI may help identify patients requiring close follow-up after standard treatment.? DCE-MRI may help plan treatment strategies for GBM patients.

     

Do we need 3D tube current modulation information for accurate organ dosimetry in chest CT? Protocols dose comparisons

Objectives

To compare the lung and breast dose associated with three chest protocols: standard, organ-based tube current modulation (OBTCM) and fast-speed scanning; and to estimate the error associated with organ dose when modelling the longitudinal (z-) TCM versus the 3D-TCM in Monte Carlo simulations (MC) for these three protocols.

Method

Five adult and three paediatric cadavers with different BMI were scanned. The CTDI_vol of the OBTCM and the fast-speed protocols were matched to the patient-specific CTDI_vol of the standard protocol. Lung and breast doses were estimated using MC with both z- and 3D-TCM simulated and compared between protocols.

Results

The fast-speed scanning protocol delivered the highest doses. A slight reduction for breast dose (up to 5.1%) was observed for two of the three female cadavers with the OBTCM in comparison to the standard. For both adult and paediatric, the implementation of the z-TCM data only for organ dose estimation resulted in 10.0% accuracy for the standard and fast-speed protocols, while relative dose differences were up to 15.3% for the OBTCM protocol.

Conclusion

At identical CTDI_vol values, the standard protocol delivered the lowest overall doses. Only for the OBTCM protocol is the 3D-TCM needed if an accurate (<10.0%) organ dosimetry is desired.

Key points

? The z-TCM information is sufficient for accurate dosimetry for standard protocols. ? The z-TCM information is sufficient for accurate dosimetry for fast-speed scanning protocols. ? For organ-based TCM schemes, the 3D-TCM information is necessary for accurate dosimetry. ? At identical CTDI _vol , the fast-speed scanning protocol delivered the highest doses. ? Lung dose was higher in XCare than standard protocol at identical CTDI _vol .

     

A simple scoring system for breast MRI interpretation: does it compensate for reader experience?

Purpose

To investigate the impact of a scoring system (Tree) on inter-reader agreement and diagnostic performance in breast MRI reading.

Materials and methods

This IRB-approved, single-centre study included 100 patients with 121 consecutive histopathologically verified lesions (52 malignant, 68 benign). Four breast radiologists with different levels of MRI experience and blinded to histopathology retrospectively evaluated all examinations. Readers independently applied two methods to classify breast lesions: BI-RADS and Tree. BI-RADS provides a reporting lexicon that is empirically translated into likelihoods of malignancy; Tree is a scoring system that results in a diagnostic category. Readings were compared by ROC analysis and kappa statistics.

Results

Inter-reader agreement was substantial to almost perfect (kappa: 0.643–0.896) for Tree and moderate (kappa: 0.455–0.657) for BI-RADS. Diagnostic performance using Tree (AUC: 0.889–0.943) was similar to BI-RADS (AUC: 0.872–0.953). Less experienced radiologists achieved AUC: improvements up to 4.7 % using Tree (P-values: 0.042–0.698); an expert’s performance did not change (P?=?0.526). The least experienced reader improved in specificity using Tree (16 %, P?=?0.001). No further sensitivity and specificity differences were found (P?>?0.1).

Conclusion

The Tree scoring system improves inter-reader agreement and achieves a diagnostic performance similar to that of BI-RADS. Less experienced radiologists, in particular, benefit from Tree.

Key Points

? The Tree scoring system shows high diagnostic accuracy in mass and non-mass lesions.? The Tree scoring system reduces inter-reader variability related to reader experience.? The Tree scoring system improves diagnostic accuracy in non-expert readers.

     

Pixel-by-pixel precise delay correction for measurement of cerebral hemodynamic parameters in H<Subscript>2</Subscript><Superscript>15</Superscript>O PET study

Objective

A new method of delay time estimation was proposed to measure precise cerebral blood flow (CBF) and arterial-to-capillary blood volume (V ₀) using ¹⁵O-water PET.

Methods

Nineteen patients with unilateral arterial stenoocclusive lesions were studied to evaluate hemodynamic status before treatment. The delay time of each pixel was calculated using least squares fitting with an arterial blood input curve adjusted to the internal carotid artery counts at the skull base. Pixel-by-pixel delay estimation provided a delay map image that could be used for precise calculation of CBF and V ₀ using a one-tissue compartment model, and the values from this method were compared with those from the slice-by-slice correction method.

Results

The affected side showed a longer delay time than the contralateral cerebral hemisphere. Although the mean cortical CBF values were not different between the two methods, the slice-by-slice delay correction overestimated CBF in the hypo perfused area. The scatter plot of V ₀ pixel values showed significant difference between the two correction methods where the slice-by-slice delay correction significantly overestimated V ₀ in the whole brain (P?<?0.05).

Conclusion

Pixel-by-pixel delay correction provides delay images as well as better estimation of CBF and V ₀, thus offering useful and beneficial information for the treatment of cerebrovascular disease.

     

The value of diffusion kurtosis magnetic resonance imaging for assessing treatment response of neoadjuvant chemoradiotherapy in locally advanced rectal cancer

Objectives

To evaluate the feasibility and value of diffusion kurtosis (DK) imaging in assessing treatment response to neoadjuvant chemoradiotherapy (CRT) in patients with locally advanced rectal cancer (LARC).

Methods

Forty-one patients were included. All patients underwent pre- and post-CRT DCE-MRI on a 3.0-Tesla MRI scanner. Imaging indices (D _app , K _app and ADC values) were measured. Change value (?X) and change ratio (r?X) were calculated. Pathological tumour regression grade scores (Mandard) were the standard reference (good responders: pTRG 1-2; poor responders: pTRG 3-5). Diagnostic performance was compared using ROC analysis.

Results

For the pre-CRT measurements, pre-D _app-10th was significantly lower in the good responder group than that of the poor responder group (p?=?0.036). For assessing treatment response to neoadjuvant CRT, pre-D _app-10th resulted in AUCs of 0.753 (p?=?0.036) with a sensitivity of 66.67 % and a specificity of 77.78 %. The r?D _app had a relatively high AUC (0.859) and high sensitivity (100 %) compared with other image indices.

Conclusions

DKI is feasible for selecting good responders for neoadjuvant CRT for LARC.

Key Points

? LARC responded well after neoadjuvant chemoradiotherapy with lower pre-D _app-10th .? LARC responded well with greater increases in mean ADC and D _app .? The change ratio of D _app (r?D _app ) had a relatively better diagnostic performance.

     

<Emphasis Type="Italic">Z</Emphasis>-score-based semi-quantitative analysis of the volume of the temporal horn of the lateral ventricle on brain CT images

The volume of the temporal horn of the lateral ventricle (THLV) on brain computed tomography (CT) images is important for neurologic diagnosis. Our purpose in this study was to develop a z-score-based semi-quantitative analysis for estimation of the THLV volume by using voxel-based morphometry. The THLV volume was estimated by use of a z-score mapping method that consisted of four main steps: anatomic standardization, construction of a normal reference database, calculation of the z score, and calculation of the mean z score in a volume of interest (VOI). A mean z score of the CT value obtained from a VOI around the THLV was used as an index for the THLV volume. CT scans from 50 subjects were evaluated. For evaluation of the accuracy of this method for estimating the THLV volume, the THLV volume was determined manually by neuroradiologists (serving as the reference volume). A mean z score was calculated from the VOI for each THLV of the 50 subjects by use of the proposed method. The accuracy of this method was evaluated by use of the relationship between the mean z score and the reference volume. The quadratic polynomial regression equation demonstrated a statistically significant correlation between the mean z score and the reference volume of the THLV (R ² = 0.94; P < 0.0001). In 92 of 100 THLVs (92 %), the 95 % prediction interval of the regional mean z score captured the reference volume of the THLV. The z-score-based semi-quantitative analysis has the potential quantitatively to estimate the THLV volume on CT images.     

<Emphasis Type="Italic">Muscina prolapsa</Emphasis> (Harris 1780)

Background

Reference data for the growth of forensically important insects mainly focus on blowflies, which essentially ignores the relevance of other insect taxa. In the present study the biology and ecology of Muscina prolapsa (Diptera: Muscidae), the larvae of which are often found on buried bodies, were analyzed under constant and varying temperature conditions in the field as well as in the laboratory.

Objective

The seasonal activity patterns and the temperature dependent development of the forensically relevant true fly M. prolapsa were analyzed to provide the basis for case relevant calculations of the post-mortem interval.

Material and methods

Using baited traps the flying activity of M. prolapsa was studied over a period of 2 years. Rat cadavers were buried (approximately 10 cm deep). Samples were taken at 2-week intervals up to 42 days and the degree of larval infestation was determined. The development was studied in the laboratory at constant temperatures at 17?℃, 20?℃ and 25?℃ as well as under varying field conditions.

Results

M. prolapsa was on the wing from March to November. All buried carcasses were heavily infested by its larvae. With increasing temperature an accelerated development was observed. Pupation occurred between 8 and 12.6 days, hatching occurred 16.7 days after oviposition but lasted up to 30 days at the lowest temperature. For the overall period of development, the lower temperature threshold was 6.7?℃.

Conclusion

The genus Muscina represents the dominant insect fauna on scantily buried cadavers and shows flying activity for most of the year. The development is temperature dependent and is, therefore, useful for calculate the post-mortem interval.

     

Gastric cancer: texture analysis from multidetector computed tomography as a potential preoperative prognostic biomarker

Objectives

To investigate the association between preoperative texture analysis from multidetector computed tomography (MDCT) and overall survival in patients with gastric cancer.

Methods

Institutional review board approval and informed consent were obtained. Fifty-six patients with biopsy-proved gastric cancer were examined by MDCT and treated with surgery. Image features from texture analysis were quantified, with and without filters for fine to coarse textures. The association with survival time was assessed using Kaplan–Meier and Cox analysis.

Results

The following parameters were significantly associated with a negative prognosis, according to different thresholds: energy [no filter] – Logarithm of relative risk (Log RR): 3.25; p?=?0.046; entropy [no filter] (Log RR: 5.96; p?=?0.002); entropy [filter 1.5] (Log RR: 3.54; p?=?0.027); maximum Hounsfield unit value [filter 1.5] (Log RR: 3.44; p?=?0.027); skewness [filter 2] (Log RR: 5.83; p?=?0.004); root mean square [filter 1] (Log RR: - 2.66; p?=?0.024) and mean absolute deviation [filter 2] (Log RR: - 4.22; p?=?0.007).

Conclusions

Texture analysis could increase the performance of a multivariate prognostic model for risk stratification in gastric cancer. Further evaluations are warranted to clarify the clinical role of texture analysis from MDCT.

Key points

? Textural analysis from computed tomography can be applied in gastric cancer.? Preoperative non-invasive texture features are related to prognosis in gastric cancer.? Texture analysis could help to evaluate the aggressiveness of this tumour.

     

Volume doubling time of lung cancer detected in idiopathic interstitial pneumonia: comparison with that in chronic obstructive pulmonary disease

Objectives

To assess the volume doubling time (VDT) of lung cancers in IIP compared with COPD.

Methods

A total of 61 patients (32 with IIP and 29 with COPD) were identified. A radiologist performed three-dimensional manual segmentation for lung cancers. VDTs were calculated and compared between two groups. Logistic regression was performed to identify factors associated with rapid tumour growth (VDT < 90 days).

Results

The median VDT of lung cancers in IIP (78.2 days) was significantly shorter than that in COPD (126.1 days; p=0.004). Squamous cell carcinoma (SqCC) was the most frequent subtype, followed by small cell lung cancer (SCLC) in IIP. In COPD, SqCC was the most frequent subtype, followed by adenocarcinoma. Rapid tumour growth was observed in 20 cancers from IIP, and in nine cancers from COPD (p=0.021). SCLC was significantly correlated with rapid tumour growth (p=0.038). Multivariate analysis revealed that the presence of IIP was the single independent predictor of rapid tumour growth (p = 0.016; odds ratio, 3.7).

Conclusions

Lung cancers in IIP showed more rapid growth, with median VDT < 90 days. Therefore, a shorter follow-up interval (<90 days) may be necessary when CT surveillance is considered in IIP patients with suspected lung cancer.

Key Points

? The median VDTs of lung cancers in IIP was 78.2 days. ? Rapid tumour growth occurred more frequently in IIP than in COPD. ? IIP was the single independent predictor of rapid tumour growth. ? Shorter CT follow-up interval may be necessary in IIP with suspicious nodules.

     

Apparent diffusion coefficient is a prognostic factor of head and neck squamous cell carcinoma treated with radiotherapy

Purpose

To evaluate the correlation between apparent diffusion coefficient (ADC) and prognosis in head and neck squamous cell carcinoma (HNSCC) treated with radiotherapy.

Materials and methods

We retrospectively studied 41 patients (38 male and 3 female, ages 37–85 years) diagnosed with HNSCC (14 oropharynx, 22 hypopharynx, 4 larynx, 1 oral cavity) and treated with radiotherapy, with radiation dose to gross tumor volume over 60 Gy. The association between age, gender, performance status, tumor location, T stage, N stage, stage, dose, overall treatment time, treatment method, adjuvant therapy, or ADC and prognosis was analyzed using a Cox proportional hazard test.

Results

ADC calculated with b-values of 300, 500, 750, and 1,000 s/mm² (ADC 300–1,000) alone showed a significant correlation with all of the analyses (p = 0.022 for local control, p = 0.0109 for regional control, p = 0.0041 for disease-free survival, and p = 0.0014 for overall survival). ADC calculated with b-values of 0, 100, and 200 s/mm² (ADC 0–200) showed a significant correlation with overall survival (p = 0.0012). N stage showed a significant correlation with regional control (p = 0.0241). Performance status showed significant association with local control (p = 0.0459), disease-free survival (p = 0.023), and overall survival (p = 0.0151), respectively.

Conclusion

ADC is an independent predictor of prognosis in HNSCC treated with radiotherapy.

     

Quantitative <Emphasis Type="Italic">T</Emphasis><Subscript>1</Subscript> and <Emphasis Type="Italic">T</Emphasis><Subscript>2</Subscript>* carotid atherosclerotic plaque imaging using a three-dimensional multi-echo phase-sensitive inversion recovery sequence: a feasibility study

Magnetic resonance imaging (MRI) is widely used to detect carotid atherosclerotic plaques. Although it is important to evaluate vulnerable carotid plaques containing lipids and intra-plaque hemorrhages (IPHs) using T₁-weighted images, the image contrast changes depending on the imaging settings. Moreover, to distinguish between a thrombus and a hemorrhage, it is useful to evaluate the iron content of the plaque using both T₁-weighted and T₂*-weighted images. Therefore, a quantitative evaluation of carotid atherosclerotic plaques using T₁ and T₂* values may be necessary for the accurate evaluation of plaque components. The purpose of this study was to determine whether the multi-echo phase-sensitive inversion recovery (mPSIR) sequence can improve T₁ contrast while simultaneously providing accurate T₁ and T₂* values of an IPH. T₁ and T₂* values measured using mPSIR were compared to values from conventional methods in phantom and in vivo studies. In the phantom study, the T₁ and T₂* values estimated using mPSIR were linearly correlated with those of conventional methods. In the in vivo study, mPSIR demonstrated higher T₁ contrast between the IPH phantom and sternocleidomastoid muscle than the conventional method. Moreover, the T₁ and T₂* values of the blood vessel wall and sternocleidomastoid muscle estimated using mPSIR were correlated with values measured by conventional methods and with values reported previously. The mPSIR sequence improved T₁ contrast while simultaneously providing accurate T₁ and T₂* values of the neck region. Although further study is required to evaluate the clinical utility, mPSIR may improve carotid atherosclerotic plaque detection and provide detailed information about plaque components.     

Multiparametric PET/MR imaging biomarkers are associated with overall survival in patients with pancreatic cancer

Purpose

To correlate the overall survival (OS) with the imaging biomarkers of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), diffusion-weighted imaging (DWI), magnetic resonance spectroscopy, and glucose metabolic activity derived from integrated fluorine 18 fluorodeoxyglucose positron emission tomography (¹⁸F–FDG PET)/MRI in patients with pancreatic cancer.

Methods

This prospective study was approved by the institutional review board and informed consent was obtained from all participants. Sixty-three consecutive patients (mean age, 62.7?±?12 y; men/women, 40/23) with pancreatic cancer underwent PET/MRI before treatment. The imaging biomarkers were comprised of DCE-MRI parameters (peak, IAUC ₆₀ , K ^trans , k _ep , v _e ), the minimum apparent diffusion coefficient (ADC_min), choline level, standardized uptake values, metabolic tumor volume, and total lesion glycolysis (TLG) of the tumors. The relationships between these imaging biomarkers with OS were evaluated with the Kaplan-Meier and Cox proportional hazard models.

Results

Seventeen (27%) patients received curative surgery, with the median follow-up duration being 638 days. Univariate analysis showed that patients at a low TNM stage (≦3, P?=?0.041), high peak (P?=?0.006), high ADC_min (P?=?0.002) and low TLG (P?=?0.01) had better OS. Moreover, high TLG/peak ratio was associated with poor OS (P?=?0.016). Multivariate analysis indicated that ADC_min (P?=?0.011) and TLG/peak ratio (P?=?0.006) were independent predictors of OS after adjustment for age, gender, tumor size, and TNM stage. The TLG/peak ratio was an independent predictor of OS in a subgroup of patients who did not receive curative surgery (P?=?0.013).

Conclusion

The flow-metabolism mismatch reflected by the TLG/peak ratio may better predict OS than other imaging biomarkers from PET/MRI in pancreatic cancer patients.

     

Subjective and objective comparisons of image quality between ultra-high-resolution CT and conventional area detector CT in phantoms and cadaveric human lungs

Objectives

To compare the image quality of the lungs between ultra-high-resolution CT (U-HRCT) and conventional area detector CT (AD-CT) images.

Methods

Image data of slit phantoms (0.35, 0.30, and 0.15 mm) and 11 cadaveric human lungs were acquired by both U-HRCT and AD-CT devices. U-HRCT images were obtained with three acquisition modes: normal mode (U-HRCT_N: 896 channels, 0.5 mm × 80 rows; 512 matrix), super-high-resolution mode (U-HRCT_SHR: 1792 channels, 0.25 mm × 160 rows; 1024 matrix), and volume mode (U-HRCT_SHR-VOL: non-helical acquisition with U-HRCT_SHR). AD-CT images were obtained with the same conditions as U-HRCT_N. Three independent observers scored normal anatomical structures (vessels and bronchi), abnormal CT findings (faint nodules, solid nodules, ground-glass opacity, consolidation, emphysema, interlobular septal thickening, intralobular reticular opacities, bronchovascular bundle thickening, bronchiectasis, and honeycombing), noise, artifacts, and overall image quality on a 3-point scale (1 = worst, 2 = equal, 3 = best) compared with U-HRCT_N. Noise values were calculated quantitatively.

Results

U-HRCT could depict a 0.15-mm slit. Both U-HRCT_SHR and U-HRCT_SHR-VOL significantly improved visualization of normal anatomical structures and abnormal CT findings, except for intralobular reticular opacities and reduced artifacts, compared with AD-CT (p < 0.014). Visually, U-HRCT_SHR-VOL has less noise than U-HRCT_SHR and AD-CT (p < 0.00001). Quantitative noise values were significantly higher in the following order: U-HRCT_SHR (mean, 30.41), U-HRCT_SHR-VOL (26.84), AD-CT (16.03), and U-HRCT_N (15.14) (p < 0.0001). U-HRCT_SHR and U-HRCT_SHR-VOL resulted in significantly higher overall image quality than AD-CT and were almost equal to U-HRCT_N (p < 0.0001).

Conclusions

Both U-HRCT_SHR and U-HRCT_SHR-VOL can provide higher image quality than AD-CT, while U-HRCT_SHR-VOL was less noisy than U-HRCT_SHR.

Key Points

? Ultra-high-resolution CT (U-HRCT) can improve spatial resolution. ? U-HRCT can reduce streak and dark band artifacts. ? U-HRCT can provide higher image quality than conventional area detector CT. ? In U-HRCT, the volume mode is less noisy than the super-high-resolution mode. ? U-HRCT may provide more detailed information about the lung anatomy and pathology.