Interpretation Of Scans Research Articles

Monoamine oxidase B inhibitor, selegiline, reduces 18F-THK5351 uptake in the human brain

Background18F-THK5351 is a quinoline-derived tau imaging agent with high affinity to paired helical filaments (PHF). However, high levels of 18F-THK5351 retention in brain regions thought to contain negligible concentrations of PHF raise questions about the interpretation of the positron emission tomography (PET) signals, particularly given previously described interactions between quinolone derivatives and monoamine oxidase B (MAO-B). Here, we tested the effects of MAO-B inhibition on 18F-THK5351 brain uptake using PET and autoradiography.MethodsEight participants (five mild cognitive impairment, two Alzheimer’s disease, and one progressive supranuclear palsy) had baseline 18F-AZD4694 and 18F-THK5351 scans in order to quantify brain amyloid and PHF load, respectively. A second 18F-THK5351 scan was conducted 1 week later, 1 h after a 10-mg oral dose of selegiline. Three out of eight patients also had a third 18F-THK5351 scan 9–28 days after the selegiline administration. The primary outcome measure was standardized uptake value (SUV), calculated using tissue radioactivity concentration from 50 to 70 min after 18F-THK5351 injection, normalizing for body weight and injected radioactivity. The SUV ratio (SUVR) was determined using the cerebellar cortex as the reference region. 18F-THK5351 competition autoradiography studies in postmortem tissue were conducted using 150 and 500 nM selegiline.ResultsAt baseline, 18F-THK5351 SUVs were highest in the basal ganglia (0.64 ± 0.11) and thalamus (0.62 ± 0.14). In the post-selegiline scans, the regional SUVs were reduced on average by 36.7% to 51.8%, with the greatest reduction noted in the thalamus (51.8%) and basal ganglia (51.4%). MAO-B inhibition also reduced 18F-THK5351 SUVs in the cerebellar cortex (41.6%). The SUVs remained reduced in the three patients imaged at 9–28 days. Tissue autoradiography confirmed the effects of MAO-B inhibition on 18F-THK5351 uptake.ConclusionsThese results indicate that the interpretation of 18F-THK5351 PET images, with respect to tau, is confounded by the high MAO-B availability across the entire brain. In addition, the heterogeneous MAO-B availability across the cortex may limit the interpretation of 18F-THK5351 scans using reference region methods.

Expert System for Bone Scan Interpretation Improves Progression Assessment in Bone Metastatic Prostate Cancer.

The bone scan index (BSI) was introduced as a quantitative tool for tumor involvement in bone of patients with metastatic prostate cancer (mPCa). The computer-aided diagnosis device for BSI analysis EXINIboneBSI seems to represent technical progress for the quantitative assessment of bone involvement. But it is not yet clear if the automated BSI (aBSI) could contribute to improved evaluation of progression in patients under antiandrogens or chemotherapy in contrast to the visual interpretation and/or conventional biomarkers such as the prostate-specific antigen (PSA). In 49 mPCa patients, bone scans were performed initially and during different therapy courses. Scans were evaluated visually and by the artificial-neural-network-based expert system EXINIboneBSI. Progression of metastatic bone involvement was defined according to the Prostate Cancer Clinical Trials Working Group 2 (PCWG2) criteria in the visual interpretation. The computer-assisted interpretation was based on different cutoff values in relative changes of the aBSI. Additionally, assessments according to bone scanning were compared to changes in the PSA value as a potential surrogate for treatment response. Using a sensitive cutoff value (5% or 10%) for the relative aBSI increase led to significantly increased progression determination compared to the visual interpretation of bone scans (49% and 43% vs. 27%, p<0.001). In 63% of the cases PSA and BSI changes matched, whereas in 18% progression was only indicated by the aBSI. A relative cutoff of 5% for the aBSI decrease could reclassify 47 serial scan pairs which were visually interpreted as stable into 22 progressive and 25 remissive scans. Distinct thresholds of the relative aBSI could help to better assess disease progression in mPCa patients. Manual corrections of the BSI values are not required in most cases. The aBSI could serve as a useful additional parameter for therapy monitoring in mPCa patients in the future.

Study on variations of Foramen Transversarium in 7th cervical vertebrae in the region of Andhra Pradesh – A clinical approach

Introduction: The anatomical knowledge of the variations in the Foramen transversarium of 7th cervical vertebrae can be of immense importance to the neurologists, radiologist, orthopedic surgeons, physiotherapist, for making the right diagnosis and can serve as a helpful guide while performing various surgeries of neck region and for proper interpretation of X-rays and CT scans. Aim: The present study has been undertaken to know the incidence of foramen transversarium in 7th dried cervical vertebrae and the contents passing through it and its clinical significance. Material and Method: A total number of 106 dried 7thcervical vertebrae were studied. Result and Discussion: In 36 seventh cervical vertebrae, variations in the Foramen transversarium were observed. Keywords: Cervical vertebrae, Foramen transversarium, accessory, Bony specule, Cervical ganglion

The impact of reconstruction and scanner characterisation on the diagnostic capability of a normal database for [123I]FP-CIT SPECT imaging

BackgroundThe use of a normal database for [123I]FP-CIT SPECT imaging has been found to be helpful for cases which are difficult to interpret by visual assessment alone, and to improve reproducibility in scan interpretation. The aim of this study was to assess whether the use of different tomographic reconstructions affects the performance of a normal [123I]FP-CIT SPECT database and also whether systems benefit from a system characterisation before a database is used.Seventy-seven [123I]FP-CIT SPECT studies from two sites and with 3-year clinical follow-up were assessed quantitatively for scan normality using the ENC-DAT normal database obtained in well-documented healthy subjects. Patient and normal data were reconstructed with iterative reconstruction with correction for attenuation, scatter and septal penetration (ACSC), the same reconstruction without corrections (IRNC), and filtered back-projection (FBP) with data quantified using small volume-of-interest (VOI) (BRASS) and large VOI (Southampton) analysis methods. Test performance was assessed with and without system characterisation, using receiver operating characteristics (ROC) analysis for age-independent data and using sensitivity/specificity analysis with age-matched normal values. The clinical diagnosis at follow-up was used as the standard of truth.ResultsThere were no significant differences in the age-independent quantitative assessment of scan normality across reconstructions, system characterisation and quantitative methods (ROC AUC 0.866–0.924). With BRASS quantification, there were no significant differences between the values of sensitivity (67.4–83.7%) or specificity (79.4–91.2%) across all reconstruction and calibration strategies. However, the Southampton method showed significant differences in sensitivity between ACSC (90.7%) vs IRNC (76.7%) and FBP (67.4%) reconstructions with calibration. Sensitivity using ACSC reconstruction with this method was also significantly better with calibration than without calibration (65.1%). Specificity using the Southampton method was unchanged across reconstruction and calibration choices (82.4–88.2%).ConclusionsThe ability of a normal [123I]FP-CIT SPECT database to assess clinical scan normality is equivalent across all reconstruction, system characterisation, and quantification strategies using BRASS quantification. However, when using the Southampton quantification method, performance is sensitive to the reconstruction and calibration strategy used.

"How to" incorporate dual-energy imaging into a high volume abdominal imaging practice.

Dual-energy CT imaging has many potential uses in abdominal imaging. It also has unique requirements for protocol creation depending on the dual-energy scanning technique that is being utilized. It also generates several new types of images which can increase the complexity of image creation and image interpretation. The purpose of this article is to review, for rapid switching and dual-source dual-energy platforms, methods for creating dual-energy protocols, different approaches for efficiently creating dual-energy images, and an approach to navigating and using dual-energy images at the reading station all using the example of a pancreatic multiphasic protocol. It will also review the three most commonly used types of dual-energy images: "workhorse" 120kVp surrogate images (including blended polychromatic and 70keV monochromatic), high contrast images (e.g., low energy monochromatic and iodine material decomposition images), and virtual unenhanced images. Recent developments, such as the ability to create automatically on the scanner the most common dual-energy images types, namely new "Mono+" images for the DSDECT (dual-source dual-energy CT) platform will also be addressed. Finally, an approach to image interpretation using automated "hanging protocols" will also be covered. Successful dual-energy implementation in a high volume practice requires careful attention to each of these steps of scanning, image creation, and image interpretation.

Explaining Radiological Emphysema Subtypes with Unsupervised Texture Prototypes: MESA COPD Study.

Pulmonary emphysema is traditionally subcategorized into three subtypes, which have distinct radiological appearances on computed tomography (CT) and can help with the diagnosis of chronic obstructive pulmonary disease (COPD). Automated texture-based quantification of emphysema subtypes has been successfully implemented via supervised learning of these three emphysema subtypes. In this work, we demonstrate that unsupervised learning on a large heterogeneous database of CT scans can generate texture prototypes that are visually homogeneous and distinct, reproducible across subjects, and capable of predicting accurately the three standard radiological subtypes. These texture prototypes enable automated labeling of lung volumes, and open the way to new interpretations of lung CT scans with finer subtyping of emphysema.

Transformation of the Jeruzalem Hills cultural landscape with modern vineyard terraces

The terraced landscape in the Jeruzalem Hills is the result of specific socioeconomic conditions under communism, and now its appearance is drastically changing for the second time in the last fifty years. This article examines the creation of the new landscape layer of modern cultivated terraces and studies their disappearance and the return to a condition similar to the original state. The analysis is based on interviews and visual interpretation of aerial laser scanning (lidar) data. It focuses on the state of the landscape before terracing, the creation of terraces and formation of a terraced landscape, and its most recent transformation into slopes without terraces. It is determined that, despite the recognized aesthetic value of terraces, legal protection in the form of a nature park has not impacted their preservation because 56% of them have already been leveled. With the conversion of vineyards to vertical plantations, a new challenge is arising: increased erosion.

Visual Estimation of Coronary Artery Calcium and the Effect of the Absence of Coronary Artery Calcium on Cardiac Events and the Interpretation of Myocardial Perfusion in Hybrid SPECT/CT Scans

The use of visual estimation of coronary artery calcium (CAC) on hybrid SPECT/CT imaging can be to provide additional source of information to assist in the interpretation of borderline myocardial perfusion images (MPI). We assessed the effect of the absence of CAC on cardiac events and the interpretation of non extensive perfusion defects. Background: At the time of MPI, hybrid systems obtain a low dose, non-ECG-gated CT scan that is used to perform attenuation correction. The utility of visual coronary CT attenuation correction scan (CTAC) in estimating actual CAC as measured by the Shemesh score (SS) was also validated. Methods: At our hospital two experienced readers, blinded to CAC scores, classified 150 patients using visual estimation of the SS. Each of the four main coronary arteries (left main, left anterior descending, left circumflex and right coronary artery) were scored 0 to 3. Calcification scoring was as follows: none (0); mild (1), when less than 1/3 of the length of the entire artery was calcified; moderate (2), when 1/3 to 2/3 of the artery was calcified; and severe (3), when more than 2/3 of the artery showed calcification. The scores for the four arteries were added to produce the total SS (0-12). To assess the effect of absence of calcium on interpretation of MPI scans we measured the size of the perfusion defect using the sum stress score (SSS) in a 17 segment model. Six month phone interviews for cardiac events was conducted at six months on 30/150 patients whose CAC score was read as zero. Results: Visual assessment of CAC had a excellent intraclass correlation coefficient of 0.973 for total calcium score, with 95% confidence interval of 0.963 to 0.980. 20% (30/150) patients had a CAC score read as zero. 97% (29/30) MPI scans read with a CAC score of zero were also read as having no inducible myocardial perfusion abnormality despite 70% (21/30) having a abnormal SSS. 10% (3/30) patients had normal coronary angiography. No patient (0/30) had a cardiac event at six months whose CAC Score was read as zero. Conclusion: CAC can be visually estimated from a CTAC scan with high degree of inter-observer reproducibility. Absence of CAC influences the interpretation of borderline MPI and may better define the risk of cardiac events during follow-up.

Performance of [18F]flutemetamol amyloid imaging against the neuritic plaque component of CERAD and the current (2012) NIA-AA recommendations for the neuropathologic diagnosis of Alzheimer's disease

IntroductionPerformance of the amyloid tracer [18F]flutemetamol was evaluated against three pathology standard of truth (SoT) measures including neuritic plaques (CERAD “original” and “modified” and the amyloid component of the 2012 NIA-AA guidelines). MethodsAfter [18F]flutemetamol imaging, 106 end-of-life patients who died underwent postmortem brain examination for amyloid plaque load. Blinded positron emission tomography scan interpretations by five independent electronically trained readers were compared with pathology measures. ResultsBy SoT, sensitivity and specificity of majority image interpretations were, respectively, 91.9% and 87.5% with “original CERAD,” 90.8% and 90.0% with “modified CERAD,” and 85.7% and 100% with the 2012 NIA-AA criteria. DiscussionThe high accuracy of either CERAD criteria suggests that [18F]flutemetamol predominantly reflects neuritic amyloid plaque density. However, the use of CERAD criteria as the SoT can result in some false-positive results because of the presence of diffuse plaques, which are accounted for when the positron emission tomography read is compared with the 2012 NIA-AA criteria.

P3.03-032 PET/CT for Patients with Very Early Clinical Stage of Malignant Pleural Mesothelioma: When Can PET/CT Detect Tumor Growth of T0/T1a Mesothelioma?: Topic: Mesothelioma Clinical

Positron Emission Tomography/Computed Tomography (PET/CT) is well recognized as an important modality to detect malignant neoplasm, which plays a crucial role in the assessment of patients with malignant pleural mesothelioma (MPM). T1a category of IMIG classification refers to an early tumor that involves the parietal pleura only. And, there are a certain number of patients with more earlier clinical stage than T1a, i.e., radiological and thoracoscopical T0 stage. Those patients with T0 stage have neither visible pleural tumor nor pathologic PET/CT findings, and they are sometimes misdiagnosed as nonspecific pleuritis after a complete investigation including thoracoscopical biopsies. Those patients will turn out to be malignant during follow-up period. The purpose of this study was to investigate when tumor growth came to be detectable with PET/CT in patients with very early clinical stage of MPM whose PET/CT had been negative. Seven histologically-proven MPM patients with T0/T1a clinical stage were followed up with PET/CT (Epithelioid/unknown; 6/1). A surgical thoracoscopy(VATS) or medical thoracoscopy with narrow band and autofluorescence imaging in addition to white light had been performed to obtain adequate materials of pleura and to diagnose T1-stage macroscopically. No patients had received talc pleurodesis. The initial thoracic CT scans showed pleural effusion without thickening of pleura, and all of the initial PET/CT evaluation was negative. The radiological examinations, including PET/CT and contrast and/or plain CT for loco-regional disease were reviewed to see tumor growth that came to be able to detect with PET scan. Interpretation of positive PET scan for malignancy is SUV>2.5. The median interval between the initial PET/CT and the follow-up PET scan to come to identify malignant nodules for the first time was 32 months (5 - 46 months). Two patients with epithelioid and unknown MPM showed a positive finding of PET scan at the site of pleural intervention (thoracoscopy/thoracentesis), of which interval were 5 and 8 months, respectively. PET-positive pleural nodules, 5.1 ～ 8.2 mm in diameter, were demonstrated in 4 patients. And, a diffuse pleural thickening with positive PET scan, 6.5 mm in thickness, was shown in 1 patient with epithelioid MPM. PET/CT is a valuable modality for detecting the progression of T0/T1a tumors > 5 mm in diameter. Interval between PET-negative T0/T1a tumor and PET-positive tumor growth is more than 2 years (median; 32 months), and tumor seeding at the site of previous pleural intervention is an early manifestation of MPM.

Utilizing 3D Printing Technology to Merge MRI with Histology: A Protocol for Brain Sectioning.

Magnetic resonance imaging (MRI) allows for the delineation between normal and abnormal tissue on a macroscopic scale, sampling an entire tissue volume three-dimensionally. While MRI is an extremely sensitive tool for detecting tissue abnormalities, association of signal changes with an underlying pathological process is usually not straightforward. In the central nervous system, for example, inflammation, demyelination, axonal damage, gliosis, and neuronal death may all induce similar findings on MRI. As such, interpretation of MRI scans depends on the context, and radiological-histopathological correlation is therefore of the utmost importance. Unfortunately, traditional pathological sectioning of brain tissue is often imprecise and inconsistent, thus complicating the comparison between histology sections and MRI. This article presents novel methodology for accurately sectioning primate brain tissues and thus allowing precise matching between histology and MRI. The detailed protocol described in this article will assist investigators in applying this method, which relies on the creation of 3D printed brain slicers. Slightly modified, it can be easily implemented for brains of other species, including humans.

Utilizing 3D Printing Technology to Merge MRI with Histology: A Protocol for Brain Sectioning

Magnetic resonance imaging (MRI) allows for the delineation between normal and abnormal tissue on a macroscopic scale, sampling an entire tissue volume three-dimensionally. While MRI is an extremely sensitive tool for detecting tissue abnormalities, association of signal changes with an underlying pathological process is usually not straightforward. In the central nervous system, for example, inflammation, demyelination, axonal damage, gliosis, and neuronal death may all induce similar findings on MRI. As such, interpretation of MRI scans depends on the context, and radiological-histopathological correlation is therefore of the utmost importance. Unfortunately, traditional pathological sectioning of brain tissue is often imprecise and inconsistent, thus complicating the comparison between histology sections and MRI. This article presents novel methodology for accurately sectioning primate brain tissues and thus allowing precise matching between histology and MRI. The detailed protocol described in this article will assist investigators in applying this method, which relies on the creation of 3D printed brain slicers. Slightly modified, it can be easily implemented for brains of other species, including humans.

Interpretation of Tc-99m sestamibi parathyroid SPECT-CT scans made easy for better surgical outcomes in patients with primary hyperparathyroidism

Interpretation of Tc-99m sestamibi parathyroid SPECT-CT scans made easy for better surgical outcomes in patients with primary hyperparathyroidism

Unusual foramen in the middle cranial fossae of adult black South African skull specimens.

Variations of the skull base foramina are quite common and often cause surgical confusion during surgical intervention of the region. The unusual foramen was observed in five (0.98%) adult skulls of black South Africans obtained from the Raymond A Dart collection of human specimens housed in the School of Anatomical Sciences at the University of the Witwatersrand. Three of the five specimens were females while the remaining two were males. In four of the five skulls, the unusual foramen was located anterolateral to the foramen rotundum both on the left and right sides. In the fifth specimen, the foramen was located posterolateral to the foramen rotundum on the left half of the middle cranial fossa. On radiographs, two specimens with unusual foramen on the right showed that the foramen opened into a canal directed inferomedially towards the pterygopalatine fossa. In the remaining three specimens, the canals were blind and shallow. This information is vital during interpretation of CT scans at the base of the skull, as any less well-known foramen may be mistaken for abnormalities leading to surgical complications.

A Survey of the Opinion and Experience of UK Dentists: Part 1: The Incidence and Cause of Iatrogenic Trigeminal Nerve Injuries Related to Dental Implant Surgery.

Dental implant-related iatrogenic trigeminal nerve (TG) injuries are proportionally increasing with dental implant surgery. This study, which is presented in greater detail over a series of articles, assessed the experience of implant-related TG nerve injuries among UK dentists. Incidence and cause of inferior alveolar nerve (IAN), mental nerve (MN), and lingual nerve (LN) injuries, together with preoperative assessment and the consent process, are presented in this article. A survey was distributed among 405 dentists attending an Association of Dental Implantology congress in the United Kingdom, of which 187 completed the survey. Most responding dentists were full-time general practitioners. Implant dentistry training was predominately through industry-organized courses. Eighty dentists encountered implant-related IAN injuries, whereas 8 encountered LN injuries. Inaccurate radiological identification of the IAN/MN and their anatomical variations (48%) were seen to be the most frequent cause of TG injuries. Disclosure of the relative risk and benefits of alternative implant treatment strategies as part of the informed consent process was not deemed to be essential by 47 (25%) of the participants. Inadequate radiological assessment was the most common cause of TG nerve injury. The use of small field of view cone beam computer tomography (CBCT) is therefore recommended when placing implants in the posterior mandible. Implant surgeons should acquire evidence-based skills in the prevention, diagnosis, and management of TG nerve injury as well as specific training on justification and interpretation of CBCT scans.

AIUM Practice Parameter for the Performance of Selected Ultrasound‐Guided Procedures

AIUM Practice Parameter for the Performance of Selected Ultrasound‐Guided Procedures

AIUM Practice Parameter for the Performance of Selected Ultrasound-Guided Procedures

AIUM Practice Parameter for the Performance of Selected Ultrasound-Guided Procedures

Value of 3D Reconstructions of CT Scans for Calcaneal Fracture Assessment.

The interpretation of CT scans for the evaluation of calcaneal fractures is difficult. Three-dimensional (3D) reconstruction (volume rendering technique [VRT]) has been valuable in the evaluation of irregularly shaped bones. However, their value for the analysis of calcaneal fractures is still debated. Therefore, the objective of this study was to assess the effect of additional use of 3D CTs in calcaneal fractures. In a prospective multicenter study, the CT data set of 5 different fractures was presented to 57 evaluators. First, the participating surgeons were asked to assess the fractures on the basis of axial, coronal, and sagittal reconstructions using a multiple-choice questionnaire. Second, 3D reconstructions (VRT) were presented. The CT scans were validated by the intraoperative findings and the results were compared to the model solution of 3 foot and ankle surgeons. Intra- and interrater reliabilities were calculated. The proportion of intraobserver agreement was 82%, with Cohen kappa of κ = 0.748 (P < .001). Interrater agreement varied between 0.772 (P = .006) for the assessment of concomitant fractures and 0.987 (P < .001) for the suggested approach. The evaluation of several items improved after presentation of the 3D CTs (Cochrane Q test, P < .001). The benefit of 3D imaging was higher in inexperienced surgeons and complex fractures (Friedman test P < .001). The evaluation of CT scans of calcaneal fractures was improved by the additional use of 3D images (VRT). Level II, prospective comparative study.

Amalgamated Reference Data for Size-Adjusted Bone Densitometry Measurements in 3598 Children and Young Adults-the ALPHABET Study.

The increasing use of dual-energy X-ray absorptiometry (DXA) in children has led to the need for robust reference data for interpretation of scans in daily clinical practice. Such data need to be representative of the population being studied and be "future-proofed" to software and hardware upgrades. The aim was to combine all available pediatric DXA reference data from seven UK centers to create reference curves adjusted for age, sex, ethnicity, and body size to enable clinical application, using in vivo cross-calibration and making data back and forward compatible. Seven UK sites collected data on GE Lunar or Hologic Scanners between 1996 and 2012. Males and females aged 4 to 20 years were recruited (n = 3598). The split by ethnic group was white 2887; South Asian 385; black Afro-Caribbean 286; and mixed heritage 40. Scans of the total body and lumbar spine (L1 to L4 ) were obtained. The European Spine Phantom was used to cross-calibrate the 7 centers and 11 scanners. Reference curves were produced for L1 to L4 bone mineral apparent density (BMAD) and total body less head (TBLH) and L1 to L4 areal bone mineral density (aBMD) for GE Lunar Prodigy and iDXA (sex- and ethnic-specific) and for Hologic (sex-specific). Regression equations for TBLH BMC were produced using stepwise linear regression. Scans of 100 children were randomly selected to test backward and forward compatibility of software versions, up to version 15.0 for GE Lunar and Apex 4.1 for Hologic. For the first time, sex- and ethnic-specific reference curves for lumbar spine BMAD, aBMD, and TBLH aBMD are provided for both GE Lunar and Hologic scanners. These curves will facilitate interpretation of DXA data in children using methods recommended in ISCD guidelines. The databases have been created to allow future updates and analysis when more definitive evidence for the best method of fracture prediction in children is agreed. © 2016 American Society for Bone and Mineral Research.

Interobserver variability in the radiological assessment of magnetic resonance imaging (MRI) including perfusion MRI in glioblastoma multiforme.

Conventional magnetic resonance imaging (MRI) has limited value for differentiation of true tumor progression and pseudoprogression in treated glioblastoma multiforme (GBM). Perfusion weighted imaging (PWI) may be helpful in the differentiation of these two phenomena. Here interobserver variability in routine radiological evaluation of GBM patients is assessed using MRI, including PWI. Three experienced neuroradiologists evaluated MR scans of 28 GBM patients during temozolomide chemoradiotherapy at three time points: preoperative (MR1) and postoperative (MR2) MR scan and the follow-up MR scan after three cycles of adjuvant temozolomide (MR3). Tumor size was measured both on T1 post-contrast and T2 weighted images according to the Response Assessment in Neuro-Oncology criteria. PW images of MR3 were evaluated by visual inspection of relative cerebral blood volume (rCBV) color maps and by quantitative rCBV measurements of enhancing areas with highest rCBV. Image interpretability of PW images was also scored. Finally, the neuroradiologists gave a conclusion on tumor status, based on the interpretation of both T1 and T2 weighted images (MR1, MR2 and MR3) in combination with PWI (MR3). Interobserver agreement on visual interpretation of rCBV maps was good (κ = 0.63) but poor on quantitative rCBV measurements and on interpretability of perfusion images (intraclass correlation coefficient 0.37 and κ = 0.23, respectively). Interobserver agreement on the overall conclusion of tumor status was moderate (κ = 0.48). Interobserver agreement on the visual interpretation of PWI color maps was good. However, overall interpretation of MR scans (using both conventional and PW images) showed considerable interobserver variability. Therefore, caution should be applied when interpreting MRI results during chemoradiation therapy.