A Novel Shorthand Approach to Knee Bone Age Using MRI: A Validation and Reliability Study

Background: Bone-age determination remains a difficult process. An atlas for bone age has been created from knee-ossification patterns on magnetic resonance imaging (MRI), thereby avoiding the need for radiographs and associated costs, radiation exposure, and clinical inefficiency. Shorthand methods for bone age can be less time-consuming and require less extensive training as compared with conventional methods. Purpose: To create and validate a novel shorthand algorithm for bone age based on knee MRIs that could correlate with conventional hand bone age and demonstrate reliability across medical trainees. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: Included in this study were adolescent patients who underwent both knee MRI and hand bone age radiographs within 90 days between 2009 and 2018. A stepwise algorithm for predicting bone age using knee MRI was developed separately for male and female patients, and 7 raters at varying levels of training used the algorithm to determine the bone age for each MRI. The shorthand algorithm was validated using Spearman rho ( rS) to correlate each rater’s predicted MRI bone age with the recorded Greulich and Pyle (G&P) hand bone age. Interrater and intrarater reliability were also calculated using intraclass correlation coefficients (ICCs). Results: A total of 38 patients (44.7% female) underwent imaging at a mean age of 12.8 years (range, 9.3-15.7 years). Shorthand knee MRI bone age scores were strongly correlated with G&P hand bone age ( rS = 0.83; P < .001). The shorthand algorithm was a valid predictor of G&P hand bone age regardless of level of training, as medical students ( rS = 0.75), residents ( rS = 0.81), and attending physicians ( rS = 0.84) performed similarly. The interrater reliability of our shorthand algorithm was 0.81 (95% CI, 0.73-0.88), indicating good to excellent interobserver agreement. Respondents also demonstrated consistency, with 6 of 7 raters demonstrating excellent intrarater reliability (median ICC, 0.86 [range, 0.68-0.96]). Conclusion: This shorthand algorithm is a consistent, reliable, and valid way to determine skeletal maturity using knee MRI in patients aged 9 to 16 years and can be utilized across different levels of orthopaedic and radiographic expertise. This method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs.

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Knee Bone Age using MRI: Validation of a Novel Method to Reduce Hand Bone Age Radiographs

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00458 ◽

2020 ◽

Vol 8 (7_suppl6) ◽

pp. 2325967120S0045

Author(s):

Blake Meza ◽

Scott LaValva ◽

Julien Aoyama ◽

Christopher DeFrancesco ◽

Brendan Striano ◽

...

Keyword(s):

Skeletal Maturity ◽

Intraclass Correlation ◽

Age Determination ◽

Bone Age ◽

Observer Agreement ◽

Knee Mri ◽

Novel Method ◽

Absolute Agreement ◽

Level Of Training ◽

Attending Physicians

Objectives: Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency. This aim of this study was to create and validate a shorthand method of bone age determination using knee MRI. Methods: We identified patients who underwent both knee MRI and hand bone age radiograph within a ninety-day period. From the findings of Pennock et al., a stepwise algorithm for predicting bone age on knee MRI was developed for males and females separately, in collaboration with a pediatric musculoskeletal radiologist. Six raters at varying levels of training used the algorithm to assign a bone age to each knee MRI. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter- (two-way random, absolute agreement) and intra-rater (two-way mixed, absolute agreement ) reliability were also calculated using ICC. Results: Thirty-eight patients (44.7% females) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand algorithm was also shown to be a reliable predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee bone age and G&P hand bone age. All respondents also demonstrated consistency, with intra-rater ICCs between 0.85-0.93. Conclusion: This shorthand algorithm is a consistent, reliable and valid way to determine skeletal maturity using knee MRI in patients aged 10 to 15 and can be utilized across different levels of orthopaedic and radiographic expertise. We believe this method is readily applicable in a clinical setting and may reduce the need for routine hand bone age radiographs. [Figure: see text][Table: see text]

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MRI KNEE BONE AGE: A NOVEL SHORTHAND APPROACH TO REDUCE BONE AGE RADIOGRAPHS IN CHILDREN

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00180 ◽

2020 ◽

Vol 8 (4_suppl3) ◽

pp. 2325967120S0018

Author(s):

Blake C. Meza ◽

Scott M. LaValva ◽

Christopher J. DeFrancesco ◽

Brendan M. Striano ◽

Julien T. Aoyama ◽

...

Keyword(s):

Radiation Exposure ◽

Medical Training ◽

Skeletal Maturity ◽

Intraclass Correlation ◽

Age Determination ◽

Bone Age ◽

Observer Agreement ◽

Rater Reliability ◽

Knee Mri ◽

The Mean

Background: Determining bone age in skeletally immature patients is critical for proper management and surgical planning. Pennock et al. recently created and validated a bone age atlas using the ossification pattern of the knee on MRI in pediatric patients, obfuscating the need for a hand radiograph and its associated cost, radiation exposure, and clinical inefficiency. Hypothesis/Purpose: We sought to validate and demonstrate reliability of a novel shorthand method of bone age determination using knee MRI across multiple levels of medical training. Methods: We identified patients who underwent knee MRI and hand bone age radiograph within a ninety-day period. In collaboration with a pediatric musculoskeletal radiologist, stepwise algorithms for predicting bone age on knee MRI were developed- one for males and one for females. Six raters at varying levels of training used the algorithm to assign a bone age for each patient. Intraclass correlation coefficient (ICC) was used to compare each rater’s predicted knee bone age to the Greulich and Pyle (G&P) hand bone age and validate the shorthand algorithm. Inter-rater reliability was also calculated using ICC. Results: Thirty-eight patients (44.7% female) underwent a knee MRI at a mean age of 12.8 years (range 9.3-15.7). The mean time between hand bone age x-ray and knee MRI was 20.2 days (range 0-88). The inter-rater reliability for the application of our shorthand algorithm was 0.81 (95% CI: 0.72 – 0.88), indicating good inter-observer agreement. The shorthand methos was shown to be a good predictor of G&P hand bone age, both for each individual rater (ICC range: 0.73 – 0.80) and the mean knee MRI bone age across all raters (ICC 0.81; 95% CI 0.65 – 0.90). It was also shown to be a consistent predictor of hand bone age across level of training, as medical students (ICC 0.77, 95% CI 0.60-0.88), residents (ICC 0.80, 95% CI 0.65-0.89), and attending physicians (ICC 0.80, 95% CI 0.63-0.89) all achieved strong correlation between predicted knee MRI bone age and G&P hand bone age. Conclusions: This novel shorthand algorithm is a reliable and valid way to determine skeletal maturity using knee MRI. It can be utilized clinically across different levels of radiographic and orthopaedic expertise and reduces the need for hand bone age radiographs and consequential radiation exposure in children. [Figure: see text][Figure: see text][Table: see text]

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A comparison of 3 different methods for assessment of skeletal age when treating leg-length discrepancies: an inter- and intra-observer study

Acta Orthopaedica ◽

10.2340/17453674.2021.1133 ◽

2022 ◽

Vol 93 ◽

pp. 222-228

Author(s):

Anne Berg Breen ◽

Harald Steen ◽

Are Pripp ◽

Ragnhild Gunderson ◽

Hilde Kristine Sandberg Mentzoni ◽

...

Keyword(s):

Skeletal Maturity ◽

Intraclass Correlation ◽

Age Determination ◽

Bone Age ◽

Systematic Difference ◽

Skeletal Age ◽

Leg Length ◽

Left Elbow ◽

Comparison Results ◽

Significant Difference

Background and purpose — Skeletal maturity is a crucial parameter when calculating remaining growth in children. We compared 3 different methods, 2 manual and 1 automated, in the radiological assessment of bone age with respect to precision and systematic difference. Material and methods — 66 simultaneous examinations of the left hand and left elbow from children treated for leg-length discrepancies were randomly selected for skeletal age assessment. The radiographs were anonymized and assessed twice with at least 3 weeks’ interval according to the Greulich and Pyle (GP) and Sauvegrain (SG) methods by 5 radiologists with different levels of experience. The hand radiographs were also assessed for GP bone age by use of the automated BoneXpert (BX) method for comparison. Results — The inter-observer intraclass correlation coefficient (ICC) was 0.96 for the GP and 0.98 for the SG method. The inter- and intra-observer standard error of the measurement (SEm) was 0.41 and 0.32 years for the GP method and 0.27 and 0.21 years for the SG method with a significant difference (p < 0.001) between the methods and between the experienced and the less experienced radiologists for both methods (p = 0.003 and p < 0.001). In 25% of the assessments the discrepancy between the GP and the SG methodwas > 1 year. There was no systematic difference comparing either manual method with the automatic BX method. Interpretation — With respect to the precision of skeletal age determination, we recommend using the SG method or preferably the automated BX method based on GP assessments in the calculation of remaining growth.

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Creation and Validation of a Shorthand Magnetic Resonance Imaging Bone Age Assessment Tool of the Knee as an Alternative Skeletal Maturity Assessment

The American Journal of Sports Medicine ◽

10.1177/03635465211032986 ◽

2021 ◽

pp. 036354652110329

Author(s):

Cary S. Politzer ◽

James D. Bomar ◽

Hakan C. Pehlivan ◽

Pradyumna Gurusamy ◽

Eric W. Edmonds ◽

...

Keyword(s):

Assessment Tool ◽

Skeletal Maturity ◽

Bone Age ◽

Mri Scan ◽

Perfect Agreement ◽

Age Assessment ◽

Left Hand ◽

Knee Mri ◽

Bone Age Assessment ◽

Hand Radiograph

Background: In managing pediatric knee conditions, an accurate bone age assessment is often critical for diagnostic, prognostic, and treatment purposes. Historically, the Greulich and Pyle atlas (hand atlas) has been the gold standard bone age assessment tool. In 2013, a shorthand bone age assessment tool based on this atlas (hand shorthand) was devised as a simpler and more efficient alternative. Recently, a knee magnetic resonance imaging (MRI) bone age atlas (MRI atlas) was created to circumvent the need for a left-hand radiograph. Purpose: To create a shorthand version of the knee MRI atlas. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: A shorthand bone age assessment method was created utilizing the previously published MRI atlas, which utilizes several criteria that are visualized across a series of images. The MRI shorthand draws on characteristic criteria for each age that are best observed on a single MRI scan. For validation, we performed a retrospective assessment of skeletally immature patients. One reader performed the bone age assessment using the MRI atlas and the MRI shorthand on 200 patients. Then, 4 readers performed the bone age assessment with the hand atlas, hand shorthand, MRI atlas, and MRI shorthand on a subset of 22 patients in a blinded fashion. All 22 patients had a knee MRI scan and a left-hand radiograph within 4 weeks of each other. Interobserver and intraobserver reliability, as well as variability among observers, were evaluated. Results: A total of 200 patients with a mean age of 13.5 years (range, 9.08-17.98 years) were included in this study. Also, 22 patients with a mean age of 13.3 years (range, 9.0-15.6 years) had a knee MRI scan and a left-hand radiograph within 4 weeks. The intraobserver and interobserver reliability of all 4 assessment tools were acceptable (intraclass correlation coefficient [ICC] ≥ 0.8; P < .001). When comparing the MRI shorthand with the MRI atlas, there was excellent agreement (ICC = 0.989), whereas the hand shorthand compared with the hand atlas had good agreement (ICC = 0.765). The MRI shorthand also had perfect agreement in 50% of readings among all 4 readers, and 95% of readings had agreement within 1 year, whereas the hand shorthand had perfect agreement in 32% of readings and 77% agreement within 1 year. Conclusion: The MRI shorthand is a simple and efficient means of assessing the skeletal maturity of adolescent patients with a knee MRI scan. This bone age assessment technique had interobserver and intraobserver reliability equivalent to or better than the standard method of utilizing a left-hand radiograph.

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3D Biometrics for Hindfoot Alignment Using Weightbearing Computed Tomography

Foot & Ankle International ◽

10.1177/1071100719835492 ◽

2019 ◽

Vol 40 (6) ◽

pp. 720-726 ◽

Cited By ~ 24

Author(s):

Jian Zhong Zhang ◽

François Lintz ◽

Alessio Bernasconi ◽

Shu Zhang ◽

Keyword(s):

Computed Tomography ◽

Comparative Study ◽

Interobserver Reliability ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Level Of Evidence ◽

Hindfoot Alignment ◽

Mean Values ◽

Intraclass Correlation Coefficients ◽

Prospective Comparative Study

Background: Weightbearing computed tomography (WBCT) is a useful tool for the assessment of hindfoot alignment (HA). Foot ankle offset (FAO) is a recently introduced parameter, determined from WBCT images using semiautomatic software. The aim of this study was to determine the clinical relevance and reproducibility of FAO for the evaluation of HA. Methods: A prospective comparative study was performed on consecutive patients requiring bilateral WBCT between September 2017 and April 2018. Based on the clinical assessment of HA, patients were divided into 3 groups: (1) normal alignment group (G1), (2) valgus (G2), and (3) varus (G3). FAO and long axial view (HACT) were measured on WBCT images, and the groups were compared. The reproducibility of FAO and HACT was determined through intraclass correlation coefficients (ICCs). Regression analysis was performed to investigate the correlation between the 2 methods. Overall, 249 feet (126 patients) were included (G1 = 115, G2 = 78, and G3 = 56 feet). Results: The mean values for FAO and HACT were 1.2% ± 2.8% and 3.9 ± 3.1, respectively, in G1; 8.1% ± 3.7% and 9.7 ± 4.9 in G2; and −6.6% ± 4.8% and −8.2 ± 6.6 in G3. Intra- and interobserver reliability was 0.987 and 0.988 for FAO and 0.949 and 0.949 for HACT, respectively. There was a good linear correlation between HACT and FAO ( R2 = 0.744), with a regression slope of 1.064. Conclusions: WBCT was a useful method for the characterization of HA. FAO was reproducible and correlated well with physical examination. Level of Evidence: Level II, prospective comparative study.

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Dynamic Footprint Measurement Collection Technique and Intrarater Reliability

Journal of the American Podiatric Medical Association ◽

10.7547/1020130 ◽

2012 ◽

Vol 102 (2) ◽

pp. 130-138 ◽

Cited By ~ 17

Author(s):

Jeanna M. Fascione ◽

Ryan T. Crews ◽

James S. Wrobel

Keyword(s):

Repeated Measures ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Healthy Population ◽

Intrarater Reliability ◽

Intraclass Correlation Coefficients ◽

Foot Posture ◽

Arch Index ◽

Post Hoc ◽

Dynamic Footprint

Background: Identifying the variability of footprint measurement collection techniques and the reliability of footprint measurements would assist with appropriate clinical foot posture appraisal. We sought to identify relationships between these measures in a healthy population. Methods: On 30 healthy participants, midgait dynamic footprint measurements were collected using an ink mat, paper pedography, and electronic pedography. The footprints were then digitized, and the following footprint indices were calculated with photo digital planimetry software: footprint index, arch index, truncated arch index, Chippaux-Smirak Index, and Staheli Index. Differences between techniques were identified with repeated-measures analysis of variance with post hoc test of Scheffe. In addition, to assess practical similarities between the different methods, intraclass correlation coefficients (ICCs) were calculated. To assess intrarater reliability, footprint indices were calculated twice on 10 randomly selected ink mat footprint measurements, and the ICC was calculated. Results: Dynamic footprint measurements collected with an ink mat significantly differed from those collected with paper pedography (ICC, 0.85–0.96) and electronic pedography (ICC, 0.29–0.79), regardless of the practical similarities noted with ICC values (P = .00). Intrarater reliability for dynamic ink mat footprint measurements was high for the footprint index, arch index, truncated arch index, Chippaux-Smirak Index, and Staheli Index (ICC, 0.74–0.99). Conclusions: Footprint measurements collected with various techniques demonstrate differences. Interchangeable use of exact values without adjustment is not advised. Intrarater reliability of a single method (ink mat) was found to be high. (J Am Podiatr Med Assoc 102(2): 130–138, 2012)

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Ossification of the phalanges of the foot and its relationship to peak height velocity and the calcaneal system

Journal of Children s Orthopaedics ◽

10.1302/1863-2548.12.170164 ◽

2018 ◽

Vol 12 (1) ◽

pp. 84-90 ◽

Cited By ~ 1

Author(s):

M. R. Garcia ◽

A. D. Nicholson ◽

A. M. Nduaguba ◽

J. O. Sanders ◽

R. W. Liu ◽

...

Keyword(s):

Skeletal Maturity ◽

Strong Association ◽

Intraclass Correlation ◽

Bone Age ◽

Peak Height ◽

Height Velocity ◽

Peak Height Velocity ◽

Guided Growth ◽

Significant Difference ◽

Stage System

Purpose There are multiple skeletal maturity grading systems, but none of them utilizes the phalanges of the foot. To minimize radiation, it would be ideal if one could assess the skeletal maturity of a foot based on bones seen on routine foot radiographs, if guided growth is being considered as a treatment option. We developed a system that correlates changes of the appearance of the foot phalanges to peak height velocity (PHV) and the recently described calcaneal apophyseal ossification grading system. Methods We selected 94 children from the Bolton-Brush study, each with consecutive radiographs from age ten to 15 years old. Using the anteroposterior view, we analyzed the ossification patterns of the phalanges and developed a six-stage system. We then determined the PHV for each subject and defined its relationship with our system. Our system was then compared with the previously established calcaneal system. Results We calculated an Intraclass correlation coefficient (ICC) range of 0.957 to 0.985 with a mean of 0.975 and interclass reliability coefficient of 0.993 indicating that this method is reliable and consistent. Our system showed no significant difference between gender with respect to PHV, which makes it a reliable surrogate for determining bone age in paediatric and adolescent patients. Conclusions Our system has a strong association with the calcaneal system. It is a simple six-stage system that is reliable and correlated more strongly with PHV than chronological age. The system requires knowledge of the ossification markers used for each stage but is easily used in a clinical setting.

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Assessment of the Intrarater and Interrater Reliability of an Established Clinical Task Analysis Methodology

Anesthesiology ◽

10.1097/00000542-200205000-00016 ◽

2002 ◽

Vol 96 (5) ◽

pp. 1129-1139 ◽

Cited By ~ 46

Author(s):

Jason Slagle ◽

Matthew B. Weinger ◽

My-Than T. Dinh ◽

Vanessa V. Brumer ◽

Kevin Williams

Keyword(s):

Real Time ◽

Task Analysis ◽

Interrater Reliability ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Intrarater Reliability ◽

Intraclass Correlation Coefficients ◽

Percent Time ◽

Analysis Methodology ◽

And Task

Background Task analysis may be useful for assessing how anesthesiologists alter their behavior in response to different clinical situations. In this study, the authors examined the intraobserver and interobserver reliability of an established task analysis methodology. Methods During 20 routine anesthetic procedures, a trained observer sat in the operating room and categorized in real-time the anesthetist's activities into 38 task categories. Two weeks later, the same observer performed task analysis from videotapes obtained intraoperatively. A different observer performed task analysis from the videotapes on two separate occasions. Data were analyzed for percent of time spent on each task category, average task duration, and number of task occurrences. Rater reliability and agreement were assessed using intraclass correlation coefficients. Results Intrarater reliability was generally good for categorization of percent time on task and task occurrence (mean intraclass correlation coefficients of 0.84-0.97). There was a comparably high concordance between real-time and video analyses. Interrater reliability was generally good for percent time and task occurrence measurements. However, the interrater reliability of the task duration metric was unsatisfactory, primarily because of the technique used to capture multitasking. Conclusions A task analysis technique used in anesthesia research for several decades showed good intrarater reliability. Off-line analysis of videotapes is a viable alternative to real-time data collection. Acceptable interrater reliability requires the use of strict task definitions, sophisticated software, and rigorous observer training. New techniques must be developed to more accurately capture multitasking. Substantial effort is required to conduct task analyses that will have sufficient reliability for purposes of research or clinical evaluation.

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Validation of a Dry Model for Assessing the Performance of Arthroscopic Hip Labral Repair

The American Journal of Sports Medicine ◽

10.1177/0363546517696316 ◽

2017 ◽

Vol 45 (9) ◽

pp. 2125-2130 ◽

Cited By ~ 11

Author(s):

Lisa Phillips ◽

Jeffrey J.H. Cheung ◽

Daniel B. Whelan ◽

Michael Lucas Murnaghan ◽

Jas Chahal ◽

...

Keyword(s):

Rating Scale ◽

Intraclass Correlation ◽

Total Asset ◽

Labral Repair ◽

Global Rating Scale ◽

Task Completion ◽

Global Rating ◽

Evaluation Tool ◽

Level Of Evidence ◽

Level Of Training

Background: Arthroscopic hip labral repair is a technically challenging and demanding surgical technique with a steep learning curve. Arthroscopic simulation allows trainees to develop these skills in a safe environment. Purpose: The purpose of this study was to evaluate the use of a combination of assessment ratings for the performance of arthroscopic hip labral repair on a dry model. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A total of 47 participants including orthopaedic surgery residents (n = 37), sports medicine fellows (n = 5), and staff surgeons (n = 5) performed arthroscopic hip labral repair on a dry model. Prior arthroscopic experience was noted. Participants were evaluated by 2 orthopaedic surgeons using a task-specific checklist, the Arthroscopic Surgical Skill Evaluation Tool (ASSET), task completion time, and a final global rating scale. All procedures were video-recorded and scored by an orthopaedic fellow blinded to the level of training of each participant. Results: The internal consistency/reliability (Cronbach alpha) using the total ASSET score for the procedure was high (intraclass correlation coefficient > 0.9). One-way analysis of variance for the total ASSET score demonstrated a difference between participants based on the level of training ( F3,43 = 27.8, P < .001). A good correlation was seen between the ASSET score and previous exposure to arthroscopic procedures ( r = 0.52-0.73, P < .001). The interrater reliability for the ASSET score was excellent (>0.9). Conclusion: The results of this study demonstrate that the use of dry models to assess the performance of arthroscopic hip labral repair by trainees is both valid and reliable. Further research will be required to demonstrate a correlation with performance on cadaveric specimens or in the operating room.

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Idiopathic Normal Pressure Hydrocephalus: Cerebral Perfusion Measured with pCASL before and Repeatedly after CSF Removal

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2014.138 ◽

2014 ◽

Vol 34 (11) ◽

pp. 1771-1778 ◽

Cited By ~ 24

Author(s):

Johan Virhammar ◽

Katarina Laurell ◽

André Ahlgren ◽

Kristina Giuliana Cesarini ◽

Elna-Marie Larsson

Keyword(s):

White Matter ◽

Normal Pressure Hydrocephalus ◽

Intraclass Correlation ◽

Correlation Coefficients ◽

Normal Pressure ◽

Idiopathic Normal Pressure Hydrocephalus ◽

Regional Variability ◽

Mri Scans ◽

Magnetic Resonance Imaging Mri ◽

Gait Function

Pseudo-continuous arterial spin labeling (pCASL) measurements were performed in 20 patients with idiopathic normal pressure hydrocephalus (iNPH) to investigate whether cerebral blood flow (CBF) increases during the first 24 hours after a cerebrospinal fluid tap test (CSF TT). Five pCASL magnetic resonance imaging (MRI) scans were performed. Two scans were performed before removal of 40 mL CSF, and the other three at 30 minutes, 4 hours, and 24 hours, respectively after the CSF TT. Thirteen different regions of interest (ROIs) were manually drawn on coregistered MR images. In patients with increased CBF in lateral and frontal white matter after the CSF TT, gait function improved more than it did in patients with decreased CBF in these regions. However, in the whole sample, there was no significant increase in CBF after CSF removal compared with baseline investigations. The repeatability of CBF measurements at baseline was high, with intraclass correlation coefficients of 0.60 to 0.90 for different ROIs, but the median regional variability was in the range of 5% to 17%. Our results indicate that CBF in white matter close to the lateral ventricles plays a role in the reversibility of symptoms after CSF removal in patients with iNPH.

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