Parental perceptions toward digital imaging and telemedicine for retinopathy of prematurity management.

BACKGROUND: Telemedicine is an emerging technology with potential to improve care for retinopathy of prematurity (ROP). This study evaluates parental perceptions about digital imaging and telemedicine for ROP care. METHODS: During a 1-year period, one parent of each infant who underwent wide-field retinal imaging for ROP was given a questionnaire designed to evaluate parental perceptions using a 5-point Likert-type scale. Five items assessed perceptions toward digital retinal imaging, and ten items assessed attitudes toward telemedicine. Construct validity of the questionnaire was examined using factor analysis. Responses were summarized using descriptive and correlational statistics. RESULTS: Forty-two parents participated. Factor analysis extracted two factors explaining 79% of the total variance in digital retinal imaging items (Cronbach's alpha = 0.843), and three factors explaining 63% of the total variance in telemedicine items (Cronbach's alpha = 0.631). Among digital imaging items, the highest mean (+/-SD) score was for "digital pictures of my child's retinopathy should be included in the permanent medical record" (4.4 +/- 0.6), and the lowest was for "digital cameras and computers are reliable" (3.8 +/- 0.8). Among telemedicine items, the highest mean (+/-SD) score was for "technology will improve the quality of medical care for my child" (4.3 +/- 0.6), and the lowest was for "technology will make it harder for a patient and doctor to establish a good relationship" (2.6 +/- 1.1). CONCLUSIONS: Parents reported positive perceptions about telemedical ROP diagnosis, but expressed some preference for face-to-face care. Telemedicine has potential to alter the nature of the patient-physician relationship.

Image analysis for retinopathy of prematurity diagnosis.

PURPOSE: To review findings from the authors' published studies involving telemedicine and image analysis for retinopathy of prematurity (ROP) diagnosis. METHODS: Twenty-two ROP experts interpreted a set of 34 wide-angle retinal images for presence of plus disease. For each image, a reference standard diagnosis was defined from expert consensus. A computer-based system was used to measure individual and linear combinations of image parameters for arteries and veins: integrated curvature (IC), diameter, and tortuosity index (TI). Sensitivity, specificity, and receiver operating characteristic areas under the curve (AUC) for plus disease diagnosis were determined for each expert. Sensitivity and specificity curves were calculated for the computer-based system by varying the diagnostic cutoffs for arterial IC and venous diameter. Individual vessels from the original 34 images were identified with particular diagnostic cutoffs, and combined into composite wide-angle images using graphics editing software. RESULTS: For plus disease diagnosis, expert sensitivity ranged from 0.308-1.000, specificity from 0.571-1.000, and AUC from 0.784 to 1.000. Among computer system parameters, one linear combination had AUC 0.967, which was greater than that of 18 of 22 (81.8%) experts. Composite computer-generated images were produced using the arterial IC and venous diameter values associated with 75% under-diagnosis of plus disease (ie, 25% sensitivity cutoff), 50% under-diagnosis of plus disease (ie, 50% sensitivity cutoff), and 25% under-diagnosis of plus disease (ie, 75% sensitivity cutoff). CONCLUSIONS: Computer-based image analysis has the potential to diagnose severe ROP with comparable or better accuracy than experts, and could provide added value to telemedicine systems. Future quantitative definitions of plus disease might improve diagnostic objectivity.

Typical variations of subthalamic electrode location do not predict limb motor function improvement in Parkinson's disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is an effective treatment for patients with medically refractory Parkinson's disease (PD). The degree to which the anatomic location of the DBS electrode tip determines the improvement of contralateral limb movement function has not been defined. This retrospective study was performed to address this issue. Forty-two DBS electrode tips in 21 bilaterally implanted patients were localized on postoperative MRI. The postoperative and preoperative planning MRIs were merged with the Stealth FrameLink 4.0 stereotactic planning workstation (Medtronic Inc., Minneapolis, MN, USA) to determine the DBS tip coordinates. Stimulation settings were postoperatively optimized for maximal clinical effect. Patients were videotaped 1 year postoperatively and assessed by a movement disorder neurologist blinded to electrode tip locations. The nine limb-related components of the Unified PD Rating Scale Part III were tabulated to obtain a limb score, and the electrode tip locations associated with the 15 least and 15 greatest limb scores were evaluated. Two-tailed t-tests revealed no significant difference in electrode tip location between the two groups in three-dimensional distance (p=0.759), lateral-medial (x) axis (p=0.983), anterior-posterior (y) axis (p=0.949) or superior-inferior (z) axis (p=0.894) from the intended anatomical target. The range of difference in tip location and limb scores was extensive. Our results suggest that anatomic targeting alone may provide the same clinical efficacy as is achieved by "fine-tuning" DBS placement with microelectrode recording to a specific target.

Retinopathy of prematurity management using single-image vs multiple-image telemedicine examinations.

PURPOSE: To compare performance of single-image vs multiple-image telemedicine examinations for retinopathy of prematurity (ROP) diagnosis. DESIGN: Prospective comparative study. METHODS: A total of 248 eyes from 67 consecutive infants underwent wide-angle retinal imaging by a trained neonatal nurse at 31 to 33 weeks and/or 35 to 37 weeks postmenstrual age (PMA) at a single academic institution. Data were uploaded to a web-based telemedicine system and interpreted by three masked retinal specialists. Diagnoses were provided based on single images, and subsequently on multiple images, from both eyes of each infant. Findings were compared to a reference standard of indirect ophthalmoscopy by a pediatric ophthalmologist. Primary outcome measures were recommended follow-up interval, presence of plus disease, presence of type-2 or worse ROP, and presence of visible peripheral ROP. RESULTS: Among the three graders, mean sensitivity/specificity for detection of infants requiring follow-up in less than one week were 0.85/0.93 by single-image examination and 0.91/0.88 by multiple-image examination at 35 to 37 weeks PMA. Mean sensitivity/specificity for detection of infants with type-2 or worse ROP were 0.82/0.95 by single-image examination and 1.00/0.91 by multiple-image examination at 35 to 37 weeks PMA. Mean sensitivity/specificity for detection of plus disease were 1.00/0.86 by single-image examination and 1.00/0.87 by multiple-image examination at 35 to 37 weeks PMA. There were no statistically-significant intragrader differences between accuracy of single-image and multiple-image telemedicine examinations for detection of plus disease. CONCLUSIONS: Single-image and multiple-image telemedicine examinations perform comparably for determination of recommended follow-up interval and detection of plus disease. This may have implications for development of screening protocols, particularly in areas with limited access to ophthalmic care.

Plus disease in retinopathy of prematurity: pilot study of computer-based and expert diagnosis.

PURPOSE: To measure accuracy of plus disease diagnosis by recognized experts in retinopathy of prematurity (ROP), and to conduct a pilot study examining performance of a computer-based image analysis system, Retinal Image multiScale Analysis (RISA). METHODS: Twenty-two ROP experts independently interpreted a set of 34 wide-angle retinal images for presence of plus disease. A reference standard diagnosis based on expert consensus was defined for each image. Images were analyzed by the computer-based system using individual and linear combinations of system parameters for arterioles and venules: integrated curvature (IC), diameter, and tortuosity index (TI). Sensitivity, specificity, and receiver operating characteristic areas under the curve (AUC) for plus disease diagnosis compared with the reference standard were determined for each expert, as well as for the computer-based system. RESULTS: Expert sensitivity ranged from 0.308 to 1.000, specificity ranged from 0.571 to 1.000, and AUC ranged from 0.784 to 1.000. Among individual computer system parameters, venular IC had highest AUC (0.853). Among all computer system parameters, the linear combination of arteriolar IC, arteriolar TI, venular IC, venular diameter, and venular TI had highest AUC (0.967), which was greater than that of 18 (81.8%) of 22 experts. CONCLUSIONS: Accuracy of ROP experts for plus disease diagnosis is imperfect. A computer-based image analysis system has potential to diagnose plus disease with high accuracy. Further research involving RISA system parameter cut-off values from this study are required to fully validate performance of this computer-based system compared with that of human experts.

Telemedical retinopathy of prematurity diagnosis: accuracy, reliability, and image quality.

OBJECTIVE: To prospectively measure accuracy, reliability, and image quality of telemedical retinopathy of prematurity (ROP) diagnosis. METHODS: Two-hundred forty-eight eyes from 67 consecutive infants underwent wide-angle retinal imaging by a trained neonatal nurse at 31 to 33 weeks' and/or 35 to 37 weeks' postmenstrual age (PMA) using a standard protocol. Data were uploaded to a Web-based telemedicine system and interpreted by 3 expert retinal specialist graders who provided a diagnosis (no ROP, mild ROP, type 2 prethreshold ROP, treatment-requiring ROP) and an evaluation of image quality for each eye. Findings were compared with a reference standard of indirect ophthalmoscopy by an experienced pediatric ophthalmologist. RESULTS: At 35 to 37 weeks' PMA, sensitivity and specificity for diagnosis of mild or worse ROP were 0.908 and 1.000 for grader A, 0.971 and 1.000 for grader B, and 0.908 and 0.977 for grader C. Sensitivity and specificity for diagnosis of type 2 prethreshold or worse ROP were 1.000 and 0.943 for grader A, 1.000 and 0.930 for grader B, and 1.000 and 0.851 for grader C. At 35 to 37 weeks' PMA, weighted kappa for intergrader reliability was 0.791 to 0.889, and kappa for intragrader reliability for detection of type 2 prethreshold or worse ROP was 0.769 to 1.000. Image technical quality was rated as "adequate" or "possibly adequate" for diagnosis in 93.3% to 100% of eyes. CONCLUSION: A telemedicine system using nurse-captured retinal images has the potential to improve existing shortcomings of ROP management, particularly at later PMAs.

Interexpert agreement of plus disease diagnosis in retinopathy of prematurity.

OBJECTIVE: To measure agreement of plus disease diagnosis among retinopathy of prematurity (ROP) experts. METHODS: A set of 34 wide-angle retinal photographs from infants with ROP was compiled on a secure Web site and was interpreted independently by 22 recognized ROP experts. Diagnostic agreement was analyzed using 3-level (plus, pre-plus, or neither) and 2-level (plus or not plus) categorizations. RESULTS: In the 3-level categorization, all experts agreed on the same diagnosis in 4 of 34 images (12%), and the mean weighted kappa statistic for each expert compared with all others was between 0.21 and 0.40 (fair agreement) for 7 experts (32%) and between 0.41 and 0.60 (moderate agreement) for 15 experts (68%). In the 2-level categorization, all experts who provided a diagnosis agreed in 7 of 34 images (21%), and the mean kappa statistic for each expert compared with all others was between 0 and 0.20 (slight agreement) for 1 expert (5%), between 0.21 and 0.40 (fair agreement) for 3 experts (14%), between 0.41 and 0.60 (moderate agreement) for 12 experts (55%), and between 0.61 and 0.80 (substantial agreement) for 6 experts (27%). CONCLUSIONS: Interexpert agreement of plus disease diagnosis is imperfect. This may have important implications for clinical ROP management, continued refinement of the international ROP classification system, development of computer-based diagnostic algorithms, and implementation of ROP telemedicine systems.

Plus disease in retinopathy of prematurity: an analysis of diagnostic performance.

PURPOSE: To measure agreement and accuracy of plus disease diagnosis among retinopathy of prematurity (ROP) experts; and to compare expert performance to that of a computer-based analysis system, Retinal Image multiScale Analysis. METHODS: Twenty-two recognized ROP experts independently interpreted a set of 34 wide-angle retinal photographs for presence of plus disease. Diagnostic agreement was analyzed. A reference standard was defined based on majority vote of experts. Images were analyzed using individual and linear combinations of computer-based system parameters for arterioles and venules: integrated curvature (IC), diameter, and tortuosity index (TI). Sensitivity, specificity, and receiver operating characteristic areas under the curve (AUC) for plus disease diagnosis were determined for each expert and for the computer-based system. RESULTS: Mean kappa statistic for each expert compared to all others was between 0 and 0.20 (slight agreement) in 1 expert (4.5%), 0.21 and 0.40 (fair agreement) in 3 experts (13.6%), 0.41 and 0.60 (moderate agreement) in 12 experts (54.5%), and 0.61 and 0.80 (substantial agreement) in 6 experts (27.3%). For the 22 experts, sensitivity compared to the reference standard ranged from 0.308 to 1.000, specificity from 0.571 to 1.000, and AUC from 0.784 to 1.000. Among individual computer system parameters compared to the reference standard, venular IC had highest AUC (0.853). Among linear combinations of parameters, the combination of arteriolar IC, arteriolar TI, venular IC, venular diameter, and venular TI had highest AUC (0.967). CONCLUSION: Agreement and accuracy of plus disease diagnosis among ROP experts are imperfect. A computer-based system has potential to perform with comparable or better accuracy than human experts, but further validation is required.

Accuracy and reliability of remote retinopathy of prematurity diagnosis.

OBJECTIVE: To determine the accuracy and reliability of retinopathy of prematurity (ROP) diagnosis using remote review of digital images by 3 masked ophthalmologist readers. METHODS: An atlas was compiled of 410 retinal photographs from 163 eyes of 64 low-birth-weight infants taken using a wide-angle digital fundus camera. All the images were independently reviewed by 3 readers, and the diagnosis in each eye was classified into 1 of 4 ordinal categories: no ROP, mild ROP, type 2 prethreshold ROP, or ROP requiring treatment. Findings were compared with a reference standard of dilated indirect ophthalmoscopy with scleral depression performed by an experienced pediatric ophthalmologist. RESULTS: Sensitivities/specificities of the diagnosis of any ROP were 0.845/0.910 for the first reader, 0.816/0.955 for the second reader, and 0.864/0.493 for the third reader. Sensitivities/specificities of the diagnosis of ROP requiring treatment were 0.850/0.960 for the first reader, 0.850/0.973 for the second reader, and 0.900/0.953 for the third reader. When ROP was classified into ordinal categories, the overall weighted kappa for interreader reliability was 0.743. Intrareader reliability for detection of low-risk prethreshold ROP or worse was 100% for all readers. CONCLUSION: The accuracy, interreader reliability, and intrareader reliability of remote diagnosis of clinically relevant ROP based on digital imaging are substantial.

Assessment of image-based technology: impact of referral cutoff on accuracy and reliability of remote retinopathy of prematurity diagnosis.

Telemedicine has potential to improve the delivery, quality, and accessibility of ophthalmic care for infants with Retinopathy of Prematurity (ROP). Using a telemedicine screening strategy, three potential diagnostic cutoffs may be used to define disease that warrants ophthalmologic referral: presence of any ROP, presence of moderate ("type-2 prethreshold") ROP, or presence of severe ROP requiring treatment. This study examines the relationship between accuracy and reliability of diagnosis by three masked ophthalmologist graders at each of these diagnostic cutoffs. The sensitivity, specificity, inter-grader reliability, and intra-grader reliability showed significant variation depending on the diagnostic cutoff, with best results at cutoffs of type-2 prethreshold ROP or treatment-requiring ROP. Before the large-scale adoption of telemedicine for image-based screening of diseases such as ROP, standards defining clinically-relevant referral cutoffs must be established, and diagnostic accuracy and reliability at these cutoffs must be characterized.

Subthalamic stimulation for Parkinson disease: determination of electrode location necessary for clinical efficacy.

OBJECT: Deep brain stimulation (DBS) of the subthalamic nucleus (STN) performed using intraoperative microelectrode recording (MER) to adjust electrode placement has become a widely used treatment for patients with advanced Parkinson disease (PD). Few studies have been conducted to examine the location of implanted electrodes relative to the intended target, and even fewer have been undertaken to investigate the degree to which variations in the location of these electrodes impacts their clinical efficacy. This study was performed to examine these issues. METHODS: The authors located 52 bilaterally implanted DBS electrode tips on postoperative magnetic resonance (MR) images obtained in 26 consecutive patients. Postoperative and preoperative planning MR images were merged to determine the DBS electrode tip coordinates relative to the midcommissural point. Surgical records listed the intended target coordinates for each DBS electrode tip. Clinical outcome assessment included the Unified PD Rating Scale (UPDRS) motor score at 1 year, standardized questionnaires, and routine follow-up visits. The mean difference between electrode tip location and intended target for all 52 electrodes was less than 2 mm in all axes. Only one electrode was farther than 3 mm from the intended target, and this was the only electrode that had to be replaced due to lack of clinical efficacy (lack of tremor suppression); its reimplantation 4 mm more medially provided excellent tremor control. High correlation coefficients indicate that the MR imaging analysis accurately determined the anatomical location of the electrode tips. Blinded videotape reviews of UPDRS motor scores comparing effects of stimulation in patients who were "on" and "off" medication identified subgroups in whom there was minimal and maximal stimulation response. Patients in these subgroups had no differences between the MR imaging-determined actual electrode tip location and its intended location. Similarly, improvements of dyskinesias and severity of symptoms encountered during the wearing-off period for the drug did not correlate with variations of electrode tip location. CONCLUSIONS: The findings in this study lead the authors to suggest that a DBS electrode placed anywhere within a 6-mm-diameter cylinder centered at the presumed middle of the STN (based on stereotactic atlas coordinates) provides similar clinical efficacy. Future studies may be warranted to evaluate prospectively the degree to which MER modification of the anatomically and/or image-determined target improves clinical efficacy of DBS electrodes.