Superior cerebellar peduncle atrophy of progressive supranuclear palsy on phase difference enhanced imaging: a comparison with Parkinson's disease

PURPOSE

Phase difference enhanced (PADRE) imaging can enhance myelin density and delineate the superior cerebellar peduncle (SCP). We aimed to determine if SCP atrophy was distinguishable on PADRE imaging and evaluate its diagnostic performance compared with previous MRI progressive supranuclear palsy (PSP) findings.

METHODS

Two reviewers measured the SCP widths on PADRE in 20 PSP and 31 Parkinson's disease (PD) patients. The SCP and middle cerebellar peduncle (MCP) widths and the pons and midbrain areas were measured on 3D-T1WI, and the ratio of the area of the pons to the area of the midbrain, the MCP/SCP ratio, and the magnetic resonance parkinsonism index (MRPI) were calculated. We used the Steel-Dwass test to compare PSP, PD, and HS, and receiver operating characteristic curve (ROC) analyses to assess the sensitivity and specificity for diagnosing PSP from PD. A comparison of ROC curves was performed between the SCP on PADRE and these 3D-T1WI parameters.

RESULTS

In radiologist 1, the SCP on PADRE in PSP (1.1 ± 0.3 mm) was significantly smaller than those in PD (2.4 ± 0.4 mm) (P < 0.001); the area under the curve (AUC) was 0.97. At a 1.75-mm cutoff value, the diagnostic sensitivity and specificity for differentiating PSP from PD were 93.5% and 100%, respectively. The AUC of the SCP on PADRE was significantly higher than the 3D-T1WI parameters (the SCP, MCP, pons area, MCP/SCP ratio, and MRPI).

CONCLUSION

Assessing SCP with PADRE imaging may yield high diagnostic accuracy for discriminating PSP from PD.

The effect of CT texture-based analysis using machine learning approaches on radiologists' performance in differentiating focal-type autoimmune pancreatitis and pancreatic duct carcinoma

PURPOSE

To develop a support vector machine (SVM) classifier using CT texture-based analysis in differentiating focal-type autoimmune pancreatitis (AIP) and pancreatic duct carcinoma (PD), and to assess the radiologists' diagnostic performance with or without SVM.

MATERIALS AND METHODS

This retrospective study included 50 patients (20 patients with focal-type AIP and 30 patients with PD) who underwent dynamic contrast-enhanced CT. Sixty-two CT texture-based features were extracted from 2D images of the arterial and portal phase CTs. We conducted data compression and feature selections using principal component analysis (PCA) and produced the SVM classifier. Four readers participated in this observer performance study and the statistical significance of differences with and without the SVM was assessed by receiver operating characteristic (ROC) analysis.

RESULTS

The SVM performance indicated a high performance in differentiating focal-type AIP and PD (AUC = 0.920). The AUC for all 4 readers increased significantly from 0.827 to 0.911 when using the SVM outputs (p = 0.010). The AUC for inexperienced readers increased significantly from 0.781 to 0.905 when using the SVM outputs (p = 0.310). The AUC for experienced readers increased from 0.875 to 0.912 when using the SVM outputs, however, there was no significant difference (p = 0.018).

CONCLUSION

The use of SVM classifier using CT texture-based features improved the diagnostic performance for differentiating focal-type AIP and PD on CT.

[Accuracy of VSRAD Analysis Using Scout Images: Comparison with Conventional 3D-T1WI]

The voxel-based specific regional analysis system for Alzheimer's disease (VSRAD), which targets volume loss in medial temporal lobe, was developed as a sensitive diagnostic tool to detect early stages of Alzheimer's disease. However, conventional three-dimensional T₁ -weighted image (3D-T₁WI) for VSRAD analysis acquires relatively long acquisition time. Recently, it became possible to acquire Scout images (Scout) for positioning as a 3D image in a short time. The aim of this study was to determine whether Scout was reliable in VSRAD. We measured voxel-based analysis of gray matter volume using VBM and Z-score of medial temporal lobe atrophy using VSRAD advance 2 from conventional 3D-T₁WI and Scout. It showed significantly different gray mass between conventional 3D-T₁WI and Scout. However, there was no significant difference in Z-score (p=0.41). The Z-scores measured from Scout and conventional 3D-T₁WI were significantly correlated (r=0.96, p<0.05). There is a possibility that Scout can be used to detect brain morphometry abnormalities instead of conventional 3D-T₁WI in the VSRAD analysis.

Accuracy of thin-slice model-based iterative reconstruction designed for brain CT to diagnose acute ischemic stroke in the middle cerebral artery territory: a multicenter study

PURPOSE

Model-based iterative reconstruction (MBIR) yields higher spatial resolution and a lower image noise than conventional reconstruction methods. We hypothesized that thin-slice MBIR designed for brain CT could improve the detectability of acute ischemic stroke in the middle cerebral artery (MCA) territory.

METHODS

Included were 41 patients with acute ischemic stroke in the MCA territory; they were seen at 4 medical centers. The controls were 39 subjects without acute stroke. Images were reconstructed with hybrid IR and with MBIR designed for brain CT at slice thickness of 2 mm. We measured the image noise in the ventricle and compared the contrast-to-noise ratio (CNR) in the ischemic lesion. We analyzed the ability of reconstructed images to detect ischemic lesions using receiver operating characteristics (ROC) analysis; 8 observers read the routine clinical hybrid IR with 5 mm-thick images, while referring to 2 mm-thick hybrid IR images or MBIR images.

RESULTS

The image noise was significantly lower on MBIR- than hybrid IR images (1.2 vs. 3.4, p < 0.001). The CNR was significantly higher with MBIR than hybrid IR (6.3 vs. 1.6, p < 0.001). The mean area under the ROC curve was also significantly higher on hybrid IR plus MBIR than hybrid IR (0.55 vs. 0.48, p < 0.036). Sensitivity, specificity, and accuracy were 41.2%, 88.8%, and 65.7%, respectively, for hybrid IR; they were 58.8%, 86.1%, and 72.9%, respectively, for hybrid IR plus MBIR.

CONCLUSION

The additional thin-slice MBIR designed for brain CT may improve the detection of acute MCA stroke.

Pediatric nasopharyngeal cancer with repeated oligometastases involving the bone, liver and distant lymph nodes who achieved cure after radiotherapy

Systemic chemotherapy is a standard treatment for Stage IVc nasopharyngeal carcinoma (NPC). Stage IVc NPC patients with oligometastases have a better prognosis, and local therapy has an important role in further development of the disease. However, the efficacy of local therapy to the metastases in patients with multiple-site and/or multiple-organ metastases is limited due to the aggressive behavior of the tumor. We report a NPC case in a pediatric patient with repeated oligometastases involving the bone, liver and distant lymph nodes who achieved 10-year disease free status after initial chemotherapy and radiotherapy to all the metastases. This very rare case demonstrated that radiotherapy to oligometastatic lesions have a potential to cure repeated oligometastases which involved multiple-organ metastases in a pediatric NPC with stage IVc.

Salvage Re-irradiation with Intensity-modulated Radiotherapy, Chemotherapy Combined with Hyperthermia for Local Recurrence of Nasopharyngeal Carcinoma After Chemoradiotherapy

A sufficient dose of radiation is difficult to administer in re-irradiation for local recurrence of cancer after radiotherapy because of the dose limitation to organs at risk. Re-irradiation cases also include radioresistant tumors that are difficult to control locally, and their prognosis is poor in general. The effect of re-irradiation using intensity-modulated radiotherapy (IMRT) has recently been reported to significantly reduce the dose to organs at risk, and the efficacy of hyperthermia has been reported for radioresistant tumors. We report a case of local recurrence after concurrent chemoradiotherapy treated with salvage re-irradiation using IMRT and chemotherapy combined with hyperthermia in a patient with nasopharyngeal carcinoma, and include a discussion of the literature.

Signal intensity of cerebral gyri in corticobasal syndrome on phase difference enhanced magnetic resonance images: Comparison of progressive supranuclear palsy and Parkinson's disease

We evaluated cerebral gyri (CG) on phase difference enhanced imaging (PADRE) of corticobasal syndrome (CBS), progressive supranuclear palsy (PSP), and Parkinson's disease (PD) patients to determine whether it is possible to discriminate among them on an individual basis. Two radiologists reviewed appearance of the normal CG and that of CBS patients on PADRE, and deviations from the appearance of the normal CG were recorded. Next, based on the CG abnormalities, two other reviewers reviewed PADRE images from 12 CBS, 14 PSP, and 30 PD patients. In healthy subjects on the PADRE images, the signal intensity (SI) of the gray matter (GM) was homogeneously, slightly hyperintense to the subcortical white matter (SCWM), and the SI of the SCWM was homogeneously hypointense. In CBS patients, hypointense layer in superficial GM and disappearance of hypointense in SCWM. The frequency of the abnormal findings on PADRE in the blinded manner by two readers was 100% (12/12), 3% (1/30), and 29% (4/14 in Reader 1) or 36% (5/14 in Reader 2) in CBS PD, and PSP patients, respectively. Laterality of the PADRE findings was showed in 12 (100%) CBS patients and 3 (21%) PSP, but not in any PD patients. The previously reported typical findings in CBS on conventional magnetic resonance image (MRIs) were observed in only 42% (5/12) of CBS patients. In conclusion, the abnormal findings in CG on PADRE appears more useful than conventional MRI findings for discriminating CBS from PD on an individual basis.

Primary Site Identification of Soft-Tissue Mass: Things to Know in MRI Assessment

The spectrum of soft-tissue mass is varied, including neoplastic and nonneoplastic/inflammatory lesions. However, soft-tissue tumors have similar imaging findings and, therefore, the diagnosis of soft-tissue mass is challenging. Although careful assessment of the internal characteristics on imaging can often narrow the differential diagnoses, the differential diagnosis may be out of the question if identification of the soft-tissue mass origin is missed. The purpose of this article is to review the imaging findings and the essential anatomy to identify the primary site of the soft-tissue mass, and discuss the associated potential pitfalls. In order not to fall into a pitfall, recognition of characteristic imaging findings indicating the origin of the soft-tissue mass and anatomical knowledge of the normal tissue distribution are necessary. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY STAGE: 3.

The brain-derived neurotrophic factor Val66Met polymorphism increases segregation of structural correlation networks in healthy adult brains

Background

Although structural correlation network (SCN) analysis is an approach to evaluate brain networks, the neurobiological interpretation of SCNs is still problematic. Brain-derived neurotrophic factor (BDNF) is well-established as a representative protein related to neuronal differentiation, maturation, and survival. Since a valine-to-methionine substitution at codon 66 of the BDNF gene (BDNF Val66Met single nucleotide polymorphism (SNP)) is well-known to have effects on brain structure and function, we hypothesized that SCNs are affected by the BDNF Val66Met SNP. To gain insight into SCN analysis, we investigated potential differences between BDNF valine (Val) homozygotes and methionine (Met) carriers in the organization of their SCNs derived from inter-regional cortical thickness correlations.

Methods

Forty-nine healthy adult subjects (mean age = 41.1 years old) were divided into two groups according to their genotype (n: Val homozygotes = 16, Met carriers = 33). We obtained regional cortical thickness from their brain T1 weighted images. Based on the inter-regional cortical thickness correlations, we generated SCNs and used graph theoretical measures to assess differences between the two groups in terms of network integration, segregation, and modularity.

Results

The average local efficiency, a measure of network segregation, of BDNF Met carriers’ network was significantly higher than that of the Val homozygotes’ (permutation p-value = 0.002). Average shortest path lengths (a measure of integration), average local clustering coefficient (another measure of network segregation), small-worldness (a balance between integration and segregation), and modularity (a representative measure for modular architecture) were not significantly different between group (permutation p-values ≧ 0.01).

Discussion and Conclusion

Our results suggest that the BDNF Val66Met polymorphism may potentially influence the pattern of brain regional morphometric (cortical thickness) correlations. Comparing networks derived from inter-regional cortical thickness correlations, Met carrier SCNs have denser connections with neighbors and are more distant from random networks than Val homozygote networks. Thus, it may be necessary to consider potential effects of BDNF gene mutations in SCN analyses. This is the first study to demonstrate a difference between Val homozygotes and Met carriers in brain SCNs.

The effect of deep convolutional neural networks on radiologists' performance in the detection of hip fractures on digital pelvic radiographs

PURPOSE

The purpose of our study is to develop deep convolutional neural network (DCNN) for detecting hip fractures using CT and MRI as a gold standard, and to evaluate the diagnostic performance of 7 readers with and without DCNN.

METHODS

The study population consisted of 327 patients who underwent pelvic CT or MRI and were diagnosed with proximal femoral fractures. All radiographs were manually checked and annotated by radiologists referring to CT and MRI for selecting ROI. At first, a DCNN with the GoogLeNet model was trained by 302 cases. The remaining 25 cases and 25 control subjects were used for the observer performance study and for the testing of DCNN. Seven readers took part in this study. A continuous rating scale was used to record each observer's confidence level. Subsequently, each observer interpreted with the DCNN outputs and rated them again. The area under the curve (AUC) was used to compare the fracture detection.

RESULTS

The average AUC of the 7 readers was 0.832. The AUC of DCNN alone was 0.905. The average AUC of the 7 readers with DCNN outputs was 0.876. The AUC of readers with DCNN output were higher than those without(p < 0.05). The AUC of the 2 experienced readers with DCNN output exceeded the AUC of DCNN alone.

CONCLUSION

For detecting the hip fractures on radiographs, DCNN developed using CT and MRI as a gold standard by radiologists improved the diagnostic performance including the experienced readers.

Hippocampal sclerosis without visually detectable hippocampal MRI abnormalities: automated subfield volumetric analysis

PURPOSE

This study aims to investigate hippocampal subfield volumes in patients with hippocampal sclerosis (HS) without visually detectable MRI abnormalities and to determine the diagnostic accuracy using hippocampal subfield volumes.

MATERIALS AND METHODS

We examined 46 patients with unilateral HS who had a histopathological diagnosis, and 54 controls. The patients were divided into two groups; visually detectable HS (n = 26) and undetectable HS (n = 20) on MRI. The volumes of hippocampal subfield using FreeSurfer were compared among the three groups. Diagnostic accuracy was calculated as the AUC of ROC using cutoff values for each individual subfield.

RESULTS

Compared with the controls, visually detectable HS showed significantly reduced volumes of all the hippocampal subfields and entire hippocampus, whereas visually undetectable HS showed significant atrophy only in the CA3 and hippocampus-amygdala-transition-area. To diagnose visually undetectable HS, the CA3 volumes had AUC of 0.719, which was higher than AUC of 0.614 based on the entire hippocampal volumes.

CONCLUSION

Visually undetectable HS demonstrated volume reductions in the CA3. Further, the CA3 volumes was more useful to diagnose visually undetectable HS compared with the entire hippocampal volumes.

Whole-brain structural covariance network abnormality in first-episode and drug-naïve major depressive disorder

There has been a growing interest in the abnormality of networks across the brain in major depressive disorder (MDD). We aimed to investigate the structural covariance networks in patients with first-episode and drug-naïve MDD using structural imaging. A total of 77 patients with first-episode and drug-naïve MDD and 79 healthy subjects (HS) were recruited, from whom high-resolution T1-weighted images were analysed. Incident component analysis was used to calculate the brain networks based on grey matter volume covariance. There were significant differences in salience network, medial temporal lobe network, default mode network and central executive network between MDD and HS (p < 0.05). Further, the disturbance of medial temporal lobe network was significantly correlated with the severity of depressive symptoms (p < 0.05). In conclusion, we found a novel abnormality in the brain network in the medial temporal lobe primarily involving the hippocampus and parahippocampal gyrus in patients with first-episode and treatment-naïve MDD.

An independent component analysis reveals brain structural networks related to TNF-α in drug-naïve, first-episode major depressive disorder: a source-based morphometric study

In a previous mouse study, social defeat stress-induced microglial activation released tumor necrosis factor-α (TNF-α), leading to neuronal changes in the prefrontal cortex (PFC) and behavioral changes (anxiety). We aimed to investigate the relationship between gray-matter (GM) structural networks and serum TNF-α in patients with major depression disorder (MDD) using multivariate source-based morphometry (SBM). Forty-five first-episode and drug-naïve MDD patients and 38 healthy subjects (HSs) were recruited. High-resolution T1-weighted imaging was performed and serum TNF-α levels were measured in all MDD patients and HSs. After acquiring GM structural networks using SBM, we compared the Z-transformed loading coefficients (Z-scores) between MDD patients and HSs, and investigated the relationship between the Z-scores and the serum TNF-α levels in MDD patients. The serum TNF-α levels in MDD patients were significantly higher than those in HSs. We extracted two independent GM structural networks (the prefrontal network and the insula-temporal network) with significant differences between MDD patients and HSs (-0.305 ± 0.85 and 0.253 ± 0.82; P = 0.03 in the prefrontal network, and -0.268 ± 0.86 and 0.467 ± 0.71; P < 0.01 in the insula-temporal network). The serum TNF-α levels were significantly correlated with the Z-scores in the prefrontal network after Bonferroni correction (r = -0.419, p < 0.01); however, the correlation in the insula-temporal network was not significant (r = -0.290, p = 0.11). Elevated serum TNF-α levels in the early stage of MDD were associated with alteration of the prefrontal network.

Structural Changes in Hippocampal Subfields in Patients with Continuous Remission of Drug-Naive Major Depressive Disorder

OBJECTIVE

Hippocampal volume is reduced in patients with major depressive disorder (MDD) compared with healthy controls. The hippocampus is a limbic structure that has a critical role in MDD. The aim of the present study was to investigate the changes in the volume of the hippocampus and its subfields in MDD patients who responded to antidepressants and subsequently were in continuous remission.

SUBJECTS AND METHODS

Eighteen patients who met the following criteria were enrolled in the present study: the DSM-IV-TR criteria for MDD, drug-naïve at least 8 weeks or more, scores on the 17-items of Hamilton Rating Scale for Depression (HAMD) of 14 points or more, and antidepressant treatment response within 8 weeks and continuous remission for at least 6 months. All participants underwent T1-weighted structural MRI and were treated with antidepressants for more than 8 weeks. We compared the volumes of the hippocampus, including its subfields, in responders at baseline to the volumes at 6 months. The volumes of the whole hippocampus and the hippocampal subfields were measured using FreeSurfer v6.0.

RESULTS

The volumes of the left cornu Ammonis (CA) 3 (p = 0.016) and the granule cell layer of the dentate gyrus (GC-DG) region (p = 0.021) were significantly increased after 6 months of treatment compared with those at baseline.

CONCLUSIONS

Increases in volume was observed in MDD patients who were in remission for at least 6 months.

Correction to: The usefulness of full-iterative reconstruction algorithm for the visualization of cystic artery on CT angiography

The authors wish to replace the Table 1.

Peritumoral Fat Content Correlates with Histological Prognostic Factors in Breast Carcinoma: A Study Using Iterative Decomposition of Water and Fat with Echo Asymmetry and Least-Squares Estimation (IDEAL)

Purpose:

To correlate peritumoral fat content using iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) with histologic prognostic factors in breast carcinoma.

Methods:

This study consisted of 100 patients who were diagnosed with invasive carcinoma of breast and underwent breast MRI including IDEAL before surgery. The scan time of IDEAL fat fraction (FF) map imaging was 33 s. Four regions of interests (ROIs), which are a distance of 5 mm from the tumor edge, and one ROI in the mammary fat of the healthy side were set on the FF map. Then average peritumoral FF values (FFt), average FF values in the healthy side (FFh), and peritumoral fat ratio (pTFR: defined as FFt/FFh) were calculated. Histologically, the presence of lymph node metastasis and the MIB-1 index were evaluated.

Results:

FFt and pTFR for breast carcinoma with lymph node metastasis (79.27 ± 10.36 and 0.897 ± 0.078) were significantly lower than those without (86.23 ± 4.53 and 0.945 ± 0.032) (P < 0.001 and P = 0.005). Spearman rank correlation suggested that the FFt correlated with the MIB-1 index (r = −340, P = 0.001).

Conclusion:

Quantification of peritumoral fat using IDEAL-iron quantification is associated with the histologic prognostic factors, and may be a practical tool for therapeutic strategy of breast carcinoma.

Pembrolizumab-induced Radiation Recall Pneumonitis After the Resolution of Typical Asymptomatic Radiation Pneumonitis

Radiation recall pneumonitis is a phenomenon in which a recall-triggering drug induces an acute inflammatory reaction in the lungs, corresponding to a previously irradiated area. Radiation recall reactions have been reported to occur following treatments with various cytotoxic anticancer agents and molecular-targeting drugs; however, only a few reports have described immune checkpoint inhibitor-induced radiation recall pneumonitis. We report a case of radiation recall pneumonitis induced by pembrolizumab in a patient with the postoperative local recurrence of non-small cell lung cancer. This case demonstrated that pembrolizumab might cause severe radiation recall pneumonitis, even after typical radiation pneumonitis has been resolved.

Association of Serum Kynurenine Levels and Neural Networks in Patients with First-Episode, Drug-Naïve Major Depression: A Source-Based Morphometry Study

PURPOSE

The kynurenine (KYN) pathway can directly or indirectly influence cerebral volume and neural integrity in patients with major depression (MD). The aim of the present study was to investigate neural network systems and the KYN pathway in patients with first-episode, drug-naïve MD.

PATIENTS AND METHODS

Twenty right-handed drug-naïve patients, with MD diagnosed using the Diagnostic and Statistical Manual for Mental Disorders, Fourth Edition, Text Revision, Research Version, were included in this study. Magnetic resonance imaging scans and scores on the Hamilton Rating Scale for Depression were assessed, and serum sampling was performed prior to the start of pharmacological treatment. Image processing and data analysis were performed according to our recently published procedure. Serum metabolomes were measured in the cation and anion modes of CE-FTMS-based metabolome analysis.

RESULTS

We found that serum KYN levels were positively correlated with the Z-scores of the salience network but not with those of the central executive network or default mode network. No associations were observed between serum glutamate levels and the Z-score of any of the three networks.

CONCLUSION

Our results indicate that serum KYN levels might affect the activity of the salience network in first-episode, drug-naïve patients with MD.

MET-04 EVALUATION OF PERITUMORAL BRAIN PARENCHYMA USING CONTRAST-ENHANCED FIESTA IMAGING FOR DIFFERENTIATING METASTATIC BRAIN TUMORS AND GLIOBLASTOMAS

Introduction: Metastatic brain tumors and glioblastomas commonly revealed heterogenous enhancement lesions with peritumoral brain edema on magnetic resonance imaging (MRI). In particular, distinguishing solitary metastatic brain tumors from glioblastomas is difficult on conventional MRI. Fast imaging employing steady-state acquisition (FIESTA) can emphasize the water content signal with a high spatial resolution. In this study, we evaluate a role of contrast-enhanced FIESTA(CE-FIESTA) by focusing on the peritumoral brain parenchyma between metastatic brain tumors and glioblastomas. Materials and Methods: We included patients who underwent initial surgery and were histologically diagnosed with metastatic brain tumor (43 cases) or glioblastoma (14 cases) between November 2008 and May 2016. We evaluated CE-FIESTA findings of peritumoral brain parenchyma. Next, we performed an observer performance study with neuroradiologists based on the findings of peritumoral brain parenchyma using conventional MRI and CE-FIESTA. Results: CE-FIESTA revealed hyperintense rim in peritumoral brain parenchyma. We classified hyperintense rim in three groups, as follow: type A, no hyperintense rim; type B, partial hyperintense rim; and type C, extended hyperintense rim. Regarding the diagnosis of metastatic brain tumors, the observer performance demonstrated high sensitivity (95.3%), specificity (85.7%) and accuracy (93.0%) of type C on CE-FIESTA, and thus, CE-FIESTA could distinguish metastatic brain tumors from glioblastomas with high accuracy. Conclusions: CE-FIESTA may provide useful information for distinguish metastatic brain tumors from glioblastomas, focusing on the differences in the peritumoral brain parenchyma.

Early volume reduction of the hippocampus after whole-brain radiation therapy: an automated brain structure segmentation study

PURPOSE

To assess atrophy differences among brain regions and time-dependent changes after whole-brain radiation therapy (WBRT).

MATERIALS AND METHODS

Twenty patients with lung cancer who underwent both WBRT and chemotherapy (WBRT group) and 18 patients with lung cancer who underwent only chemotherapy (control group) were recruited. Three-dimensional T1WI were analyzed to calculate volume reduction ratio after WBRT in various brain structures. The volume reduction ratio of the hippocampus was compared among following 3 periods: 0-3, 4-7, and 8-11 months after WBRT.

RESULTS

The volume reduction ratio of the hippocampus was significantly higher in the WBRT group than in the control group (p < 0.05). In WBRT group, the volume reduction ratio of the hippocampus was significantly higher than that of the cortex and white matter (p < 0.05). There were significant differences in the volume reduction ratio between of 0-3 months and that of 4-7 months (p = 0.02) and between 4-7 months and that of 8-11 months (p = 0.01).

CONCLUSION

The hippocampus is more vulnerable to the radiation compared with other brain regions and may become atrophic even in the early stage after WBRT.

Relationship between VEGF-related gene polymorphisms and brain morphology in treatment-naïve patients with first-episode major depressive disorder

Vascular endothelial growth factor (VEGF) is involved in the development of major depressive disorder (MDD). Recently, a genome-wide association study has revealed that four VEGF-related single nucleotide polymorphisms (SNPs) (i.e., rs4416670, rs6921438, rs6993770 and rs10738760) were independently associated with circulating VEGF levels. The current study investigated the relationship between brain volume and these four SNPs in first-episode drug-naïve MDD patients. A total of 38 first-episode drug-naïve MDD patients and 39 healthy subjects (HS) were recruited and underwent high-resolution T1-weighted imaging. Blood samples were collected from all the participants for serum VEGF assays and VEGF-related SNPs genotyping. Genotype-diagnosis interactions related to whole-brain cortical thickness and hippocampal subfield volumes were evaluated for the four SNPs. The results revealed a genotype-diagnosis interaction only for rs6921438 (i.e., the MDD patients and HS with the G/G genotype versus the MDD patients and HS with A-carrier genotype) in the subiculum of the left hippocampus (p < 0.05), and not the other SNPs. There was a volume reduction in the left subiculum of G/G genotype patients compared with the other groups. The "hypochondriasis" scores of the HAMD-17 scale were significantly higher in the G/G genotype patients than the A-carrier genotype patients. The association was observed between VEGF-related SNP rs6921438 and subiculum atrophy in first-episode drug-naïve MDD patients.

Facial nerve atrophy in patients with amyotrophic lateral sclerosis: Evaluation with fast imaging employing steady-state acquisition (FIESTA)

BACKGROUND

In amyotrophic lateral sclerosis (ALS), motor neurons in the brainstem markedly deplete, whereas sensory neurons are less severely affected.

PURPOSE

To determine whether facial nerve (FN) measurement on 3D fast imaging employing steady-state acquisition (FIESTA) is useful for ALS diagnosis.

STUDY TYPE

Retrospective.

SUBJECTS

Fifteen ALS patients and 16 controls.

FIELD STRENGTH/SEQUENCE

3T FIESTA MR.

ASSESSMENT

The cross-sectional area of the FN and cochlear nerve (CN) were measured, and the FN/CN ratio (FCR) was assessed. For qualitative assessment, the FN cross-sectional area was compared with that of the CN and the following scores were assigned: score 1 (large), the FN is larger than the CN; score 2 (almost equal), the size difference between the FN and CN is within 10%; score 3 (small), the FN is smaller than the CN (10-50%); score 4 (significantly small), size of the FN is less than half the size of the CN.

STATISTICAL TESTS

The differences in FCR between the ALS patients and the controls were tested using the Wilcoxon Mann-Whitney U-test. For the qualitative and quantitative assessments, we performed a receiver operating characteristic analysis for the diagnosis of ALS with an abnormal finding as score 3 or 4.

RESULTS

The mean FCR was significantly smaller for ALS patients (0.71 ± 0.17) than for controls (0.95 ± 0.08) (P < 0.001) and the area under the curve was 0.93. When an FN score was 3 or 4, indicative of FN atrophy, the sensitivity and specificity values of FIESTA for discriminating ALS patients from controls were 93.3% (14/15) and 90.0% (18/20), respectively.

DATA CONCLUSION

The FN atrophy revealed on FIESTA, which may reflect lower motor neuron impairment in ALS, allowed us to distinguish ALS patients from controls with a high degree of accuracy.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2020;51:757-766.

Evaluation of oxygen extraction fraction in systemic lupus erythematosus patients using quantitative susceptibility mapping

The purposes of this study are to assess the oxygen extraction fraction (OEF) changes on MRI-based quantitative susceptibility mapping (QSM) in systemic lupus erythematosus (SLE) patients and to determine whether QSM-OEF is associated with disease activity in SLE. We enrolled 42 SLE patients and 20 healthy subjects (HS) who had no pathologies on conventional brain MRI. Disease activity was assessed using SLE Disease Activity Index (SLEDAI). For the measurement of QSM-OEF, QSM data were analysed using the Perfusion Mismatch Analyzer software program. Spearman's or Pearson's correlation coefficients were calculated, and independent predictors were identified through a multiple linear regression analysis. QSM-OEF was significantly higher in SLE than that in HS (51.3 ± 10.1 vs. 40.5 ± 3.7, p < 0.001). QSM-OEF was positively correlated with SLEDAI and the presence of neuropsychiatric symptom (NPS) scores (ρ = 0.663, p < 0.001 and ρ = 0.340, p = 0.028). At multiple linear regression analysis, SLEDAI and NPS were independently associated with QSM-OEF (standardized β = 0.426, p = 0.016 and standardized β = 6.148, p = 0.029). In the SLE patients, QSM-OEF is associated with disease activity, which might predict an increased risk of stroke in SLE.

The usefulness of full-iterative reconstruction algorithm for the visualization of cystic artery on CT angiography

PURPOSE

To evaluate the potential of full-iterative reconstruction (IR) for improving image quality of the cystic artery on CT angiography and to assess observer performance.

METHODS

Thirty patients who underwent both liver dynamic CT and conventional angiography were included in this retrospective study. All CT data were reconstructed through filtered back projection (FBP), adaptive iterative dose reduction 3D (AIDR3D), and forward-projected, model-based, iterative reconstruction solution (FIRST), respectively. In objective study, we analyzed mean ΔCT numbers (the difference between the HU peak of the vessel and the background) and full-width at tenth-maximum (FWTM) of three parts of the cystic artery by profile curve method comparing the three reconstructions. Subjectively, visualization was evaluated using a four-point scale performed by two blinded observers. ANOVA was used for statistical analysis.

RESULTS

In all parts of the cystic artery, the mean ΔCT number of FIRST was shown to be significantly better than that of FBP and AIDR3D (p < 0.05). FWTM in FIRST was the smallest in all of the vessels. The mean visualization score was significantly better with FIRST than with other CT reconstructions (p < 0.05).

CONCLUSIONS

The FIRST algorithm led to improved CTA visualization of the cystic artery.

Correction to: Ultrashort time-to-echo quantitative magnetic resonance imaging of the triangular fibrocartilage: differences in position

The original version of this article, published on 03 September 2018, unfortunately contained a mistake.

A single-nucleotide polymorphism influences brain morphology in drug-naïve patients with major depressive disorder

OBJECTIVE

Recently, a genome-wide association study successfully identified genetic variants associated with major depressive disorder (MDD). The study identified 17 independent single-nucleotide polymorphisms (SNPs) significantly associated with diagnosis of MDD. These SNPs were predicted to be enriched in genes that are expressed in the central nervous system and function in transcriptional regulation associated with neurodevelopment. The study aimed to investigate associations between 17 SNPs and brain morphometry using magnetic resonance imaging (MRI) in drug-naïve patients with MDD and healthy controls (HCs).

METHODS

Forty-seven patients with MDD and 42 HCs were included. All participants underwent T1-weighted structural MRI and genotyping. The genotype-diagnosis interactions associated with regional cortical thicknesses were evaluated using voxel-based morphometry for the 17 SNPs.

RESULTS

Regarding rs301806, an SNP in the RERE genomic regions, we found a significant difference in a genotype effect in the right-lateral orbitofrontal and postcentral lobes between diagnosis groups. After testing every possible diagnostic comparison, the genotype-diagnosis interaction in these areas revealed that the cortical thickness reductions in the MDD group relative to those in the HC group were significantly larger in T/T individuals than in C-carrier ones. For the other SNPs, no brain area was noted where a genotype effect significantly differed between the two groups.

CONCLUSIONS

We found that a RERE gene SNP was associated with cortical thickness reductions in the right-lateral orbitofrontal and postcentral lobes in drug-naïve patients with MDD. The effects of RERE gene polymorphism and gene-environment interactions may exist in brain structures of patients with MDD.

Genetic effects on white matter integrity in drug-naive patients with major depressive disorder: a diffusion tensor imaging study of 17 genetic loci associated with depressive symptoms

BACKGROUND

A genome-wide association study using megadata identified 17 single-nucleotide polymorphisms (SNPs) in candidate genes for major depressive disorder (MDD). These MDD susceptibility polymorphisms may affect white matter (WM) integrity. This study aimed to investigate the relationship between WM alterations and 17 SNPs in candidate genes for MDD in the first depressive episode of drug-naive MDD patients using a tract-based spatial statistics (TBSS) method.

METHODS

Thirty-five drug-naive MDD patients with a first depressive episode and 47 age-and sex-matched healthy subjects underwent diffusion tensor imaging scans and genotyping. The genotype-diagnosis interactions related to WM integrity were evaluated using TBSS for the 17 SNPs.

RESULTS

For the anterior thalamic radiation, cingulum, corticospinal tract, inferior fronto-occipital fasciculus, inferior longitudinal fasciculus, superior longitudinal fasciculus, uncinate fasciculus, forceps major, and forceps minor, the genotype effect significantly differed between diagnosis groups (P<0.05, family-wise error corrected) in only one SNP, rs301806, in the arginine-glutamic acid dipeptide (RE) repeats (RERE) gene.

CONCLUSION

The RERE polymorphism was associated with WM alterations in first-episode and drug-naive MDD patients, which may be at least partially related to the manifestation of MDD. Future studies are needed to explore the gene-environment interactions with regard to individual WM integrity.

COMT polymorphism regulates the hippocampal subfield volumes in first-episode, drug-naive patients with major depressive disorder

Purpose: Compared with healthy subjects (HS), patients with major depressive disorder (MDD) exhibit volume differences that affect the volume changes in several areas such as the limbic, cortical, subcortical, and white matter. Catechol-O-methyltransferase (COMT) is a methylation enzyme that catalyzes endogenous catecholamines. The Val158Met polymorphism of COMT has been reported to affect the dopamine (DA) levels, which plays an important role in psychiatric diseases. However, the relationships among both DA levels, COMT genotype, and brain morphology are complicated and controversial. In previous studies that investigated the hippocampal subfields, the greatest brain abnormalities in MDD patients were observed in Cornu Ammonis (CA)1 and the subiculum, followed by that in CA2-3. We have prospectively demonstrated the relationship between the single-nucleotide polymorphism of the Val158Met COMT gene (rs4680) and the hippocampal subfields in drug-naive MDD patients. Patients and methods: In this study, we compared 27 MDD patients and 42 HS who were divided into groups based on their COMT genotype. The effects of the diagnosis, genotype, and genotype-diagnosis interaction related to CA1 and the subiculum volumes, as well as the whole-brain cortical thickness, were evaluated by performing a FreeSurfer statistical analysis of high-resolution magnetic resonance imaging (MRI) findings. Results: The results revealed that there was a statistically significant interaction between the effects of diagnosis and genotype on the right subiculum (a component of the hippocampus). Conclusion: This Val158Met COMT polymorphism may influence the subiculum volume in drug-naive, first-episode MDD patients.

Predictive gamma passing rate by dose uncertainty potential accumulation model

PURPOSE

Intensity-modulated radiation therapy (IMRT) utilizes many small fields for producing a uniform dose distribution. Therefore, there are many field junctions in the target region, and resulting dose uncertainties are accumulated. However, such accumulation of the dose uncertainty has not been implemented in the current practice of IMRT dose verification. The purpose of this study is to develop a method to predict the gamma passing rate (GPR) using a dose uncertainty accumulation model.

METHODS

Thirty-three intensity-modulated (IM) beams for head-and-neck cases with step-and-shoot techniques were used in this study. The treatment plan was created using the XiO treatment planning system (TPS). The IM beam was produced by the ONCOR Impression Plus linear accelerator. MapCHECK was used to measure the dose distribution. The distribution of a dose uncertainty potential (DUP) was generated by in-house software that accumulated field shapes weighted by a segmental monitor unit, followed by Gaussian folding. The width of the Gaussian was determined from the width of the lateral penumbra. The dose difference between the calculated and measured doses was compared with the estimated DUP at each point. The GPR of each beam was predicted for 2%/2-mm, 3%/2-mm, and 3%/3-mm tolerances by its own DUP histogram and a GPR-vs-DUP correlation of other beams using the leave-one-out cross-validation method. The predicted GPR was compared with the measured GPR to evaluate the performance of this prediction method. The criteria for the predicted GPR corresponding to a measured GPR ≥ 90% were estimated to examine the feasibility of estimating the measured GPR by this GPR prediction method.

RESULTS

The DUP was confirmed to have proportionality to the standard deviation (SD) of the dose difference. The SDs of the difference between the measured and predicted GPRs were 3.1, 1.7, and 1.4% for 2%/2-mm, 3%/2-mm, and 3%/3-mm tolerances, respectively. The criteria of the predicted GPR corresponding to the measured GPR ≥ 90% were 94.1 and 95.0% with confidence levels of 99 and 99.9%, respectively.

CONCLUSION

In this study, we confirmed the good proportionality between the dose difference and the estimated DUP. The results showed a feasibility to predict the dose difference from DUP as estimated by a DUP accumulation model. The predicted GPR developed in this study showed good accuracy for planar dose distributions of head and neck IMRT. The prediction method developed in this study is considered to be feasible as a substitute for the current practice of measurement-based verification of the dose distribution with gamma analysis.

Ultrashort time-to-echo quantitative magnetic resonance imaging of the triangular fibrocartilage: differences in position

PURPOSE

To compare T2* values of the triangular fibrocartilage (TFC) obtained by ultrashort time-to-echo (UTE) techniques at the neutral position, ulnar flexion of the wrist, and pronation of the forearm.

MATERIALS AND METHODS

MR imaging was performed in ten healthy volunteers with a 3-T MR system by using an eight-channel knee coil. Coronal wrist T2* maps from three-dimensional cone UTE pulse sequences were obtained at the neutral, ulnar flexion, and pronation positions (TR: 19 ms, TE: 0.032 ms/4 ms/8 ms/12 ms, FOV: 18 cm, matrix: 430 × 430, section thickness: 1.5 mm, scan time: 8 min 31 s). UTE-T2* maps were calculated on a pixel-by-pixel basis for all structures of the wrist visualized in the coronal planes. The entire region of interest (ROI) for TFC was manually delineated, and the average T2* value was calculated for each ROI by three radiologists. The Kruskal-Wallis test, Wilcoxon signed-rank test, or intraclass correlation coefficients (ICC) were used for statistics.

RESULTS

The difference in the average T2* value among the three groups according to the forearm/wrist position was significant (p < 0.001). The T2* value of the TFC at pronation (mean ± 2 SD: 7.92 ± 1.37 ms) was significantly lower than those at the neutral (10.08 ± 1.90 ms) and ulnar flexion positions (9.15 ± 1.03 ms) (p < 0.017). The ICC showed a substantial interobserver agreement in the T2* value measurements of the TFC (ICC = 0.986).

CONCLUSION

T2* relaxation time measurement of the TFC using UTE may be useful for assessing the loading effect by the forearm/wrist position.

KEY POINTS

• The T2* value of the TFC may reflect the biomechanics of the wrist joint. • Acute loading at pronation results in a decrease in the T2* value of the TFC. • Quantitative wrist UTE MRI was successfully performed in vivo.

Evaluation of Peritumoral Brain Parenchyma Using Contrast-Enhanced 3D Fast Imaging Employing Steady-State Acquisition at 3T for Differentiating Metastatic Brain Tumors and Glioblastomas

BACKGROUND

Metastatic brain tumors and glioblastomas are the 2 of the most common brain neoplasms in adults. However, distinguishing solitary metastatic brain tumors from glioblastomas on conventional magnetic resonance imaging remains particularly challenging. Thus, we aimed to retrospectively assess the role of contrast-enhanced fast imaging employing steady-state acquisition (CE-FIESTA) imaging in distinguishing between metastatic brain tumors and glioblastomas.

MATERIALS AND METHODS

Forty-three patients with metastatic brain tumors and 14 patients with glioblastomas underwent conventional magnetic resonance imaging and CE-FIESTA before surgery. First, 1 neuroradiologist and 1 neurosurgeon classified the CE-FIESTA findings for the peritumoral brain parenchyma by consensus. Next, the 2 neuroradiologists performed an observer performance study comparing tumor shape classification (smooth or irregular margins), a classic imaging finding, with the CE-FIESTA classification of the peritumoral brain parenchyma.

RESULTS

The CE-FIESTA findings for the peritumoral brain parenchyma were classified as follows: type A, no hyperintense rim; type B, partial hyperintense rim; and type C, extended hyperintense rim. With regard to the diagnosis of metastatic brain tumors, the observer performance study demonstrated that the mean sensitivity, specificity, and accuracy of an extended hyperintense rim classification (type C) on CE-FIESTA images were 95.3%, 85.7%, and 93.0%, respectively. The accuracy of the CE-FIESTA classification was significantly higher than that of the tumor shape classification.

CONCLUSIONS

CE-FIESTA images may provide useful information for distinguishing metastatic brain tumors from glioblastomas, especially when focusing on differences in the peritumoral brain parenchyma.

Relationship between white matter integrity and serum inflammatory cytokine levels in drug-naive patients with major depressive disorder: diffusion tensor imaging study using tract-based spatial statistics

Recently, accumulated evidence has indicated a role of inflammation in the pathogenesis of major depressive disorder (MDD). Therefore, we evaluated the relationship between white matter integrity and serum cytokine levels during the first depressive episode in drug-naive MDD patients, using a tract-based spatial statistics (TBSS) method. A total of 35 drug-naive MDD patients with a first depressive episode and 35 healthy subjects (HS) underwent diffusion tensor imaging, and an analysis was conducted using TBSS. We measured serum cytokine levels (interleukin [IL]-1β, IL-6, interferon-γ, and tumor necrosis factor-α). Fractional anisotropy (FA) values of the bilateral inferior fronto-occipital fasciculus (IFOF) and genu of the corpus callosum in MDD patients were decreased significantly to the HS (p < 0.05 with family-wise error [FWE] correction) and were significantly inversely correlated with the IL-1β levels (p < 0.05, with FWE correction). No regions showed a correlation between FA values and other serum cytokine levels. Our results suggested that the microstructural changes in IFOF and genu of the corpus callosum are associated with the high IL-1β levels in the early stage of MDD.

Relationship between interleukin (IL)-6 and brain morphology in drug-naïve, first-episode major depressive disorder using surface-based morphometry

There is a growing body of evidence to support the involvement of proinflammatory cytokines in the pathophysiology of depression; however, no previous studies have examined the relationship between cytokines and the brain morphology of patients with major depressive disorder (MDD). We therefore evaluated the relationship between serum cytokine levels and cortical thinning during the first depressive episode in drug-naïve patients with MDD. We measured the serum cytokine levels (IL-1β, IL-6, IFN-γ, and TNFα), and whole-brain cortical thickness and hippocampal subfield volumes on brain magnetic resonance imaging (MRI) using surface-based morphometry in 40 patients with MDD and 47 healthy volunteers (controls). Only the serum IL-6 level was significantly higher in patients with MDD than in controls. The prefrontal cortex (PFC) thickness was significantly reduced in patients with MDD, and showed a significant inverse correlation with the serum IL-6 level. Although high serum IL-6 levels were correlated with reduced left subiculum and right CA1, CA3, CA4, GC-DG, subiculum, and whole hippocampus volumes, the presence or absence of MDD had no effect on the volume of any hippocampal subfields. Our results suggest that IL-6 may play a key role in the morphological changes in the PFC during the early stage of MDD.

Signal Change of Acute Cortical and Juxtacortical Microinfarction on Follow-Up MRI

BACKGROUND AND PURPOSE

Although the clinical importance of cortical microinfarcts has become well-recognized recently, the evolution of cortical microinfarcts on MR imaging is not fully understood. The aim of this study was to examine the temporal changes in acute cortical microinfarcts using susceptibility-weighted imaging and conventional MR imaging.

MATERIALS AND METHODS

Patients with acute infarcts located in the cortical and/or juxtacortical region measuring ≤10 mm in axial diameter based on diffusion-weighted imaging who had a follow-up 3T MR imaging were retrospectively included in the study. All lesions did not show hypointensity on initial T2*WI. For cortical and/or juxtacortical microinfarcts detected on initial DWI, 2 neuroradiologists evaluated the follow-up MR imaging (T2WI, FLAIR, T2*WI, and SWI) and assessed lesion signal intensities and locations (cortical microinfarcts or microinfarcts with juxtacortical white matter involvement).

RESULTS

On initial DWI, 2 radiologists observed 180 cortical and/or juxtacortical microinfarcts in 35 MR imaging examinations in 25 patients; on follow-up, the neuroradiologists identified 29 cortical microinfarcts (16%) on T2WI, 9 (5%) on FLAIR, 4 (2%) on T2*, and 97 (54%) on SWI. All cortical microinfarcts detected with any follow-up MR imaging showed hyperintensity on T2WI/FLAIR and/or hypointensity on T2*WI and SWI.

CONCLUSIONS

SWI revealed conversion (paramagnetic susceptibility changes) of acute cortical microinfarcts, suggesting that a substantial number of cortical microinfarcts may contain hemorrhagic components.

Lymphocytic focus score is positively related to airway and interstitial lung diseases in primary Sjögren's syndrome

OBJECTIVE

Although high-resolution computed tomography (HRCT) is useful for the characterization of minute morphological changes in the lungs, no study has investigated risk factors for lung involvement detected by HRCT in patients with Sjögren's syndrome with or without respiratory symptoms. The aim of the current study was to investigate risk factors for lung involvement in patients with primary Sjögren's syndrome detected by HRCT, with a particular focus on airway and interstitial lung diseases.

METHODS

We performed a retrospective cohort study of patients with primary Sjögren's syndrome and investigated risk factors for lung involvement detected by HRCT. A total of 101 patients with primary Sjögren's syndrome with initial HRCT examinations were enrolled.

RESULTS

Higher age, dry mouth, and higher labial gland biopsy focus scores (≥4) were risk factors for airway diseases (odds ratio [OR] 1.064 confidence interval [CI] 1.026-1.102, OR 8.795 CI 2.317-33.378 and OR 3.261 CI 1.100-9.675, respectively) in the multivariable analysis. Higher age, male sex, and higher labial gland biopsy focus scores (≥4) were risk factors for interstitial lung diseases (OR 1.078 CI 1.032-1.127, OR 12.178 CI 1.121-132.307 and OR 3.954 CI 1.423-10.987, respectively) in the multivariable analysis. The presence of anti-T-lymphotropic virus type 1 antibodies was significantly more common in patients with airway diseases.

CONCLUSIONS

This study showed significant associations of labial gland biopsy focus scores and dry mouth with pulmonary manifestations in patients with primary Sjögren's syndrome. Focus scores as well as dry mouth may reflect lymphoproliferative activity in the lungs in patients with primary Sjögren's syndrome.

Clinical performance metrics of 3D stereoscopic digital mammography compared with 2D digital mammography: observer study

OBJECTIVE

To assess the clinical performance of three-dimensional stereoscopic digital mammography (3DsDM) compared with two-dimensional digital mammography (2DDM) for breast lesion diagnosis with jackknife free-response receiver operating characteristics (JAFROC) observer study.

METHODS

40 pairs of standard-dose 2DDM and their 3DsDM images were used for an observer performance study. A total of 18 lesions were identified as the reference standard of actionable breast lesions (Breast Imaging Reporting and Data System Category 3 or more) by two breast radiologists. Ratings and locations of "lesions" determined by observers were utilized for assessing the statistical significance of differences between eight radiologists' performances with the 2DDM images and with the 3DsDM images in jackknife free-response receiver operating characteristic analysis.

RESULTS

The average figure-of-merit values for all radiologists increased to a statistically significant degree, from 0.859 with the 2DDM images to 0.936 with the 3DsDM images (p < 0.001). The average sensitivity for detecting actionable lesions was improved from 74.3 to 92.4% at a false-positive rate of 0.2 per case by use of the 3DsDM images. The mean reading time per case with 2DDM images was not significantly different from that with 3DsDM images.

CONCLUSION

The use of 3DsDM would improve the observer performance for breast lesion without considerably extending the reading time. Advances in knowledge: Use of 3DsDM improves radiologists' performance for breast lesion detection.

Salvage radiotherapy for second oligo-recurrence in patients with breast cancer

A new concept designated 'oligo-recurrence (OR)' has been proposed, which indicates one to several distant metastases/recurrences in one or more organs, which can be treated with local therapy, after the primary site of the cancer has been controlled. The purpose of this study was to assess the efficacy and toxicity of salvage radiotherapy (RT) for the second OR of breast cancer. The second OR was defined as once-salvaged patients with OR who had a second failure that was also detected as the state of OR. Twenty-one patients with second OR were treated with salvage RT and were retrospectively analyzed. The sites of the second OR were locoregional recurrence in 7 patients and distant metastasis in 14 patients. Salvage RT was performed at a median total dose of 60 Gy. Nineteen (90%) patients had an objective response. The median overall survival and progression-free survival (PFS) times were 41 and 24 months after salvage RT for the second OR, respectively. The 3-year local (in-field) control (LC) rates were 93%. The toxicities were mild; acute toxicities ≥Grade 3 were seen in one patient with Grade 3 dermatitis, and no late toxicity ≥Grade 2 was observed. In conclusion, salvage RT for the second OR was able to achieve a better LC rate and longer PFS time without inducing severe toxicity, and therefore may be a potentially effective modality for inducing long-term survival in select patients.

The usefulness of mobile insulator sheets for the optimisation of deep heating area for regional hyperthermia using a capacitively coupled heating method: phantom, simulation and clinical prospective studies

PURPOSE

To evaluate the feasibility and efficacy of deep regional hyperthermia with the use of mobile insulator sheets in a capacitively coupled heating device.

MATERIALS AND METHODS

The heat was applied using an 8-MHz radiofrequency-capacitive device. The insulator sheet was inserted between the regular bolus and cooled overlay bolus in each of upper and lower side of the electrode. Several settings using the insulator sheets were investigated in an experimental study using an agar phantom to evaluate the temperature distributions. The specific absorption rate (SAR) distributions in several organs were also computed for the three-dimensional patient model. In a clinical prospective study, a total of five heating sessions were scheduled for the pelvic tumours, to assess the thermal parameters. The conventional setting was used during the first, third and fifth treatment sessions, and insulator sheets were used during the second and fourth treatment sessions.

RESULTS

In the phantom study, the higher heating area improved towards the centre when the mobile insulator sheets were used. The subcutaneous fat/target ratios for the averaged SARs in the setting with the mobile insulator (median, 2.5) were significantly improved compared with those in the conventional setting (median, 3.4). In the clinical study, the thermal dose parameters of CEM43°CT90 in the sessions with the mobile insulator sheets (median, 1.9 min) were significantly better than those in the sessions using a conventional setting (median, 1.0 min).

CONCLUSIONS

Our novel heating method using mobile insulator sheets was thus found to improve the thermal dose parameters. Further investigations are expected.

Detection of lung carcinoma with predominant ground-glass opacity on CT using temporal subtraction method

PURPOSE

To evaluate the usefulness of the CT temporal subtraction (TS) method for the detection of the lung cancer with predominant ground-glass opacity (LC-pGGO).

MATERIALS AND METHODS

Twenty-five pairs of CT and their TS images in patients with LC-pGGO (31 lesions) and 25 pairs of those in patients without nodules were used for an observer performance study. Eight radiologists participated and the statistical significance of differences with and without the CT-TS was assessed by JAFROC analysis.

RESULTS

The average figure-of-merit (FOM) values for all radiologists increased to a statistically significant degree, from 0.861 without CT-TS to 0.912 with CT-TS (p < .001). The average sensitivity for detecting the actionable lesions improved from 73.4 % to 85.9 % using CT-TS. The reading time with CT-TS was not significantly different from that without.

CONCLUSION

The use of CT-TS improves the observer performance for the detection of LC-pGGO.

KEY POINTS

• CT temporal subtraction can improve the detection accuracy of lung cancer. • Reading time with temporal subtraction is not different from that without. • CT temporal subtraction improves observer performance for ground-glass/subsolid nodule detection.