Visual results and subjective satisfaction after implantation of two different trifocal diffractive intraocular lenses models (AcrySof IQ PanOptix and AT LISA tri 839 MP)

BACKGROUND

This study aimed to compare visual results following the implantation of two distinct diffractive trifocal IOLs utilizing various vision evaluation techniques and subjective satisfaction.

METHODS

The study included 32 eyes receiving AcrySof IQ PanOptix implantation and 32 receiving AT LISA tri 839 MP. Post-operative examination at one year included uncorrected visual acuity (UCVA), distance-corrected visual acuity (DCVA) at 4 m, 80 cm, 60 cm, and 40 cm, Contrast sensitivity under photopic and mesopic conditions, and a questionnaire on subjective quality of vision, optical phenomena, and spectacle independence.

RESULTS

The two groups were similar in baseline demographics, pre-operative visual, biometric data (except for axial length), and surgical paraments. The PanOptix outperformed the AT LISA tri in the intermediate range when using the standard visual acuity testing (UCVA: 0.23 ± 0.14 logMAR vs. 0.31 ± 0.17 logMAR, p = 0.04; BCVA: 0.21 ± 0.12 vs. 0.28 ± 0.14, p = 0.03) and in the intermediate and far range when using the interactive computer program (intermediate: UNVA "E" optotype test: 0.05 ± 0.12 vs. 0.12 ± 0.13, p = 0.03; Far: UNVA "E" optotype: 0.07 ± 0.12 vs. 0.13 ± 0.10, p = 0.05). In addition, the PanOptix group had higher contrast sensitivity under photopic and mesopic conditions with and without glare at all spatial frequencies. There was no difference in subjective outcomes between the groups.

CONCLUSIONS

Patients who received PanOptix IOL had better visual outcomes for intermediate and far with higher contrast sensitivity under various conditions. Based on patients ' needs and demands, these results could support discussion when tailoring the optimal multifocal IOl.

Effector T Cells Promote Fibrosis in Corneal Transplantation Failure

Purpose

To evaluate whether fibrosis contributes to corneal transplant failure and to determine whether effector CD4+ T cells, the key immune cells in corneal transplant rejection, play a direct role in fibrosis formation.

Methods

Allogeneic corneal transplantation was performed in mice. Graft opacity was evaluated by slit-lamp biomicroscopy, and fibrosis was assessed by in vivo confocal microscopy. Expression of alpha-smooth muscle actin (α-SMA) in both accepted and failed grafts was assessed by real-time PCR and immunohistochemistry. Frequencies of graft-infiltrating CD4+ T cells, neutrophils, and macrophages were assessed using flow cytometry. In vitro, MK/T-1 corneal fibroblasts were co-cultured with activated CD4+CD25- effector T cells isolated from corneal transplant recipient mice, and α-SMA expression was quantified by real-time PCR and ELISA. Neutralizing antibody was used to evaluate the role of interferon gamma (IFN-γ) in promoting α-SMA expression.

Results

The majority of failed grafts demonstrated clinical signs of fibrosis which became most evident at week 6 after corneal transplantation. Failed grafts showed higher expression of α-SMA as compared to accepted grafts. Flow cytometry analysis showed a significant increase in CD4+ T cells in failed grafts compared to accepted grafts. Co-culture of activated CD4+CD25- effector T cells with corneal fibroblasts led to an increase in α-SMA expression by fibroblasts. Inhibition of IFN-γ in culture significantly suppressed this increase in α-SMA expression as compared to immunoglobulin G control.

Conclusions

Fibrosis contributes to graft opacity in corneal transplant failure and is mediated at least in part by effector CD4+ T cells via IFN-γ.

Is Demodex Blepharitis Connected With Cataract Surgery?

PURPOSE

To determine whether there is an increased incidence of Demodex of the eyelashes among patients after cataract extraction surgery.

DESIGN

Prospective, noncomparative clinical study.

METHODS

A cohort of patients who underwent cataract extraction surgery had several eyelashes removed preoperatively that were examined independently by the hospital laboratory for the presence of the Demodex mite. This was repeated 3 weeks after surgery. During several postoperative weeks, patients received the standard treatment of steroid drops alone for a period as individually required.

RESULTS

A total of 62 patients were included in the study (31 men and 31 women), with a mean age of 71.04 years (range, 47-87). In the group positive for Demodex, the male-to-female ratio was 2:3 (P = .2772). Demodex colonization was observed in 22.58% of samples before cataract surgery and in 32.26% after cataract surgery and topical postoperative steroid therapy (P = .0143).

CONCLUSIONS

There is a statistically significant increase in Demodex colonization of eyelashes after cataract surgery and postoperative topical steroid treatment. Although Demodex colonization does not necessarily cause blepharitis, our findings of increased colonization should raise the possibility of Demodex blepharitis being considered by ophthalmologists in patients with chronic postoperative eye discomfort after cataract surgery. This study was carried out at the Emek Medical Center.

Differences in retinal images quality between normal and subclinical keratoconus and its association to posterior corneal asymmetry

PURPOSE

To compare retinal image quality in subclinical keratoconus and normal eyes using a double-pass aberrometer and to correlate it with posterior surface deformation.

METHODS

Sixty normal corneas were compared to 20 subclinical keratoconus (SKC) corneas. Retinal image quality was assessed using a double-pass system in all the eyes. The objective scatter index (OSI) modulation transfer function (MTF) cutoff, Strehl ratio (SR), and Predicted Visual Acuity (PVA) values at 100%, 20%, and 9% were calculated and compared between the groups. Posterior corneal asymmetry was measured using a combined Placido Dual Scheimpflug Analyzer, and correlations were tested with all optical quality parameters.

RESULTS

Significant decrease in optical quality parameters was observed in SKC eyes compared with that in normal eyes. Subclinical KC eyes expressed greater scattering (OSI = 0.66 ± 0.36 vs 0.47 ± 0.26) and reduced contrast images (MTF and SR) than normal eyes, with 38.82 ± 9.4 and 0.22 ± 0.04, and 44.35 ± 7.1 and 0.24 ± 0.04, respectively. The reduction in the image contrast parameters (MTF and SR) was strongly correlated to the level of posterior corneal asymmetry in SKC. The greater the posterior asymmetry, the more affected was the image contrast, with r = -0.63 and -0.59, respectively for MTF and SR.

CONCLUSION

Retinal image quality was significantly more affected in eyes with subclinical keratoconus than in normal eyes. The reduction in optical quality observed in subclinical keratoconus was strongly associated with the increased asymmetry of the posterior cornea.

SYRINGE DESIGN AND FILLING TECHNIQUE AFFECT ACCURACY OF ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR INTRAVITREAL INJECTIONS

PURPOSE

To evaluate the effect of syringe design and filling technique on the accuracy of anti-vascular endothelial growth factor delivery.

METHODS

Volume output was measured with three syringe designs: a 1.0-mL slip-tip syringe, a 1.0-mL Luer-lock syringe, and a ranibizumab prefilled syringe-using two filling techniques ("upward" and "downward") and two fluids (water and bevacizumab). A total of 300 simulated injections were performed. Accuracy was determined by difference from the intended volume of 50 µ L and by mean absolute percentage error.

RESULTS

Volume outputs were significantly different between syringe designs, with mean values of 61.99 ± 4.18 µ L with the 1-mL slip-tip syringe, 57.43 ± 4.95 µ L with the Luer-lock 1-mL syringe, and 51.06 ± 4.74 µ L with the ranibizumab syringe, making the latter the most accurate syringe. There were 37 cases (12.3%) of underdosing below 50 µ L, the majority of which occurred with the ranibizumab syringe. The "downward" technique reduced the occurrence of air bubbles.

CONCLUSION

Intravitreal injections using 1.0-mL syringes are less accurate than using the ranibizumab prefilled syringe, which has a low-volume and low dead-space plunger design. The variability in volume output may result in less predictable treatment response, especially in cases of underdosing, which were more common with the ranibizumab syringe.

Real-world experience with belantamab mafodotin therapy for relapsed/refractory multiple myeloma: A multicentre retrospective study

Belantamab mafodotin, an immuno-conjugate targeting B-cell maturation antigen, showed single-agent activity in phase 1 and 2 studies, and was recently approved for heavily pretreated relapsed/refractory multiple myeloma (RRMM) patients. Real-world data and long-term follow-up are scarce. We conducted a multisite retrospective study aimed to assess safety and efficacy of belantamab mafodotin monotherapy administered via the GSK expanded access compassionate care programme. One-hundred and six RRMM patients were treated with belantamab mafodotin between July 2019 and March 2021. The median age was 69.4 years. Patients were heavily pretreated with a median of six (range 2-11) prior therapy lines. Major adverse effects included ocular toxicity (keratopathy 68.4%, grade ≥3: 40.5%; blurred vision 36.8%, grade ≥3: 6.3%), thrombocytopenia (27.4%, grade ≥3: 17.9%) and infections (11.3%, grade ≥3: 7.5%). Median follow-up time was 11.9 [95% confidence interval (CI) 10.0-13.8] months. Overall response rate was 45.5%. Median progression-free survival was 4.7 (95% CI 3.5-5.9) months in the entire cohort and 8.8 (95% CI 6.6-10.9) months among responders. Median overall survival was 14.5 (95% CI 9.5-19.6) months, and not reached for responders. To conclude, in a real-world setting, belantamab mafodotin monotherapy showed efficacy comparable with the prospective clinical trials, with a tolerable toxicity profile.

POS0892 IDENTIFICATION OF DEFINED MICROANGIOPATHIC CHANGES IN NAILFOLD CAPILLAROSCOPY IMAGES OF PATIENTS WITH SYSTEMIC SCLEROSIS USING A VISION TRANSFORMER MODEL – A MONOCENTRIC IMPLEMENTATION AND VALIDATION COHORT STUDY

Background

An accurate assessment of nailfold capillaroscopy (NFC) images has great importance in the diagnosis and prognosis of systemic sclerosis (SSc). To overcome some of the inherent problems with NFC image analysis (operator/observer bias, time requirements), there is an interest to automate and standardize NFC image assessment using computer vision algorithms, such as the Vision Transformer (ViT), which are based on recent advances in deep learning.

Objectives

Our aims were (1) to implement and assess the performance and the reliability of ViT in detecting changes on NFC images, and (2) to compare the performance of ViT to that of practicing rheumatologists.

Methods

For this study, we used NFC images of patients with SSc enrolled in our European Scleroderma Trials and Research group (EUSTAR) and Very Early Diagnosis of Systemic Sclerosis (VEDOSS) local registries. Concretely, we included routine NFC images (all NFC images available – digit II to V of both hands-, irrespective of any image artefacts) of patients aged ≥ 18 years with visits between 2012 and 2021, who fulfilled either the 2013 American College of Rheumatology / European League Against Rheumatism classification criteria for SSc (established disease) or the preliminary criteria for VEDOSS (mild/early disease).

ViT was trained to identify the following NFC signs of microangiopathy: enlarged capillaries (apex diameter of the capillary > 20 µm, and < 50µm), giant capillaries (> 50 µm), loss of capillaries (< 7 capillaries/mm), and microhaemorrhages. Absence of any of these signs was considered as being a “normal NFC”, while presence of any of these signs was seen as an abnormal NFC image. Its performance was evaluated in a cross-fold (k = 5) validation setting, and the gold standard was the treating physician. Area under the ROC curve (AUC) was used as indicator of the performance. Considered cut-offs for AUC were 90-100% - excellent, 80-89.9% - good, 70-79.9% - fair, 60-69.9% - poor, 50-59.9% - fail. From the first cross-fold, a randomly sampled reliability set was created which was used to compare the NFC assessment performance of four rheumatologists (three invited and trained annotators and the treating physician) with that of of ViT.

Results

We analysed 17,126 NFC images of 234 EUSTAR patients (14.6% males, 67.8% limited cutaneous SSc, median age 57 years, median disease duration 9 years) and 55 VEDOSS patients (92.7% females, median age 44 years, median time elapsed since first Raynaud’s phenomenon 5 years). ViT had fair to excellent performance in identifying the different NFC changes across all five folds (of 3443 NFC images each), with an area under the ROC curve ranging from 78.59% to 90.4% (Figure 1a).

Figure 1.

Performance of the ViT: (a) AUCs values for ViT in diagnosing the respective feature on NFC image. (b) Sensitivity / specificity trade-off across the images in the reliability set. The blue lines show the ROC curves corresponding to the ViT predictions, with ViT’s AUC, “optimal” sensitivity and specificity shown in the box. Also shown are the point performances of each of the four annotators, with performances below the blue line indicating lower performance than ViT.

In the reliability set (see Figure 1b), we observed highest performance for diagnosing giant capillaries (AUC =92.89%) followed by identification of enlarged capillaries (AUC = 91.7%). Good AUCs were seen in depicting capillary loss (AUC = 87.3%), microhemorrhages (AUC = 85.9%) and the abnormal/normal NFC classification (AUC = 84.7%). The rheumatologists had generally higher performance in assessing NFC images. However, ViT outperformed two rheumatologists with different experience in classifying capillary loss and enlarged capillaries, respectively.

Conclusion

ViT is a modern, well performing and readily available AI model to assess signs of microangiopathy on NFC images acquired during routine practice.

Disclosure of Interests

Alexandru Garaiman: None declared, Farhad Nooralahzadeh: None declared, Carina Mihai Speakers bureau: MEDtalks Switzerland, Mepha, Nikitas Gkikopoulos: None declared, Nicolas Perez Gonzalez: None declared, Mike O. Becker Speakers bureau: Mepha, MSD, Novartis, GSK, Bayer and Vifor, Oliver Distler Speakers bureau: Bayer, Boehringer Ingelheim, Medscape, Novartis, Roche, Pfizer, Roche, Sanofi, Consultant of: Abbvie, Acceleron, Alcimed, Amgen, AnaMar, Arxx, AstraZeneca, Baecon, Blade, Bayer, Boehringer Ingelheim, ChemomAb, Corbus, CSL Behring, Galapagos, Glenmark, GSK, Horizon, Inventiva, iQvia, Kymera, Lupin, Medac, Medscape, Miltenyi Biotec, Mitsubishi Tanabe, MSD, Prometheus Biosences, Roche, Roivant, Topadur and UBC, Lilly, Pfizer, Grant/research support from: Kymera, Mitsubishi Tanabe, Michael Krauthammer Speakers bureau: Oncobit, Britta Maurer Speakers bureau: Boehringer-Ingelheim, Medtalk, Pfizer, Roche, Actelion, Mepha, and MSD, Consultant of: Novartis, Boehringer Ingelheim, Janssen-Cilag, Grant/research support from: AbbVie, Protagen, Novartis Biomedical Research

Distinguishing Highly Asymmetric Keratoconus Eyes Using Dual Scheimpflug/Placido Analysis

PURPOSE

To identify the best metrics or combination of metrics that provide the highest predictive power between normal eyes and the clinically unaffected eye of patients with highly asymmetric keratoconus using data from a Dual Scheimpflug/Placido device.

DESIGN

Retrospective case-control study.

METHODS

Combined Dual Scheimpflug/Placido imaging was obtained from the Galilei G4 device (Ziemer Ophthalmic Systems AG, Port, Switzerland) in 31 clinically unaffected eyes with highly asymmetric keratoconus and 178 eyes from 178 patients with bilaterally normal corneal examinations that underwent uneventful LASIK with at least 1 year follow-up. Receiver operating characteristic (ROC) curves were generated to determine area under the curve (AUC), sensitivity, and specificity for 87 metrics, and logistic regression modeling was used to determine optimal variable combinations.

RESULTS

No individual metric achieved an AUC greater than 0.79. A combined model consisting of 9 metrics yielded an AUC of 0.96, with 90.3% sensitivity and 92.6% specificity. Among those 9 metrics included, 5 related to corneal pachymetry: Opposite Sector Index and Anterior Height BFS Z from the anterior surface, Asphericity and Asymmetry Index, Posterior Height BFS Z, and Posterior Height BFS X from the posterior surface. The strongest variable in the model was the thinnest point location on the horizontal (x) axis.

CONCLUSION

While individual metrics performed poorly, using a combination of metrics from the combined Dual Scheimpflug/Placido device provided a useful model for differentiating normal corneas from the clinically normal eyes of patients with highly asymmetric keratoconus. Pachymetry values were the most impactful metrics.

Corneal Blood Staining after Complicated Cataract Surgery

Purpose

To report the case of a patient with corneal blood staining after a complicated cataract surgery.

Observations

We report on a 68-year-old woman who developed corneal blood staining secondary to hyphema after cataract surgery, despite the fact that intraocular pressure was not increased for a prolonged time. The corneal staining spontaneously cleared from the periphery towards the center. It was fully resolved after 2.5 years of follow-up.

Conclusions and Importance

In case of hyphema induced by cataract surgery, performance of early anterior chamber washout should be considered to prevent corneal blood staining and poor visual outcome.

Publication outcome of abstracts submitted to the American Academy of Ophthalmology meeting

Objective

Abstracts submitted to meetings are subject to less rigorous peer review than full-text manuscripts. This study aimed to explore the publication outcome of abstracts presented at the American Academy of Ophthalmology (AAO) annual meeting.

Methods

Abstracts presented at the 2008 AAO meeting were analyzed. Each presented abstract was sought via PubMed to identify if it had been published as a full-text manuscript. The publication outcome, journal impact factor (IF), and time to publication were recorded.

Results

A total of 690 abstracts were reviewed, of which 39.1% were subsequently published. They were published in journals with a median IF of 2.9 (range 0–7.2) and a median publication time of 426 days (range 0–2,133 days). A quarter were published in the journal Ophthalmology, with a shorter time to publication (median 282 vs. 534 days, p=0.003). Oral presentations were more likely to be published than poster presentations (57.8% vs. 35.9%, p<0.001) and in journals with higher IFs (3.2 vs. 2.8, p=0.02). Abstracts describing rare diseases had higher publication rates (49.4% vs. 38.0%, p=0.04) and were published in higher IF journals (3.7 vs. 2.9, p=0.03), within a shorter period of time (358 vs. 428 days, p=0.03). In multivariate analysis, affiliation with an institute located in the United States (p=0.002), abstracts describing rare diseases (p=0.03), and funded studies (p=0.03) were associated with publication in higher IF journals.

Conclusions

Almost 40% of abstracts were published. Factors that correlated with publication in journals with higher IF were a focus on rare diseases, affiliation with a US institute, and funding.

Positive Results Bias and Impact Factor in Ophthalmology

PURPOSE

Previous studies in several fields of medicine have reported an association between the result of a trial (positive versus negative) and the impact factor of the journal in which it is published. The purpose of this study was to test the hypotheses that in the field of ophthalmology: (1) studies with positive results have a greater chance of being published in journals with a higher impact factor; (2) likewise, studies with a larger number of participants are more likely to be published in journals with a higher impact factor.

METHODS

In this retrospective study, consecutive randomized, controlled trials conducted in the field of ophthalmology between 1 January 2010 and 1 January 2013 were retrieved from PubMed. Each study was classified as having either a positive or negative result. A positive result was defined as a study in which there was a statistically significant difference between groups (p < 0.05). The impact factor of the journal in which the study was published was retrieved. The number of patients enrolled and whether or not the trial was placebo controlled was documented as well.

RESULTS

Out of 2524 studies identified, 892 met the inclusion criteria. Studies with positive results were published in journals with a significantly higher impact factor than that of the journals in which negative result studies were published (p < 0.001). Studies with positive results had a slightly larger number of participants than studies with negative results (p = 0.028). In multiple regression analysis, the ranked impact factor was significantly predicted by the primary outcome (positive versus negative results) and the number of participants in a study (total R(2 )= 2.95, p < 0.001).

CONCLUSIONS

In the field of ophthalmology, articles with positive results are currently published in journals with a higher impact factor. This finding supports the ongoing occurrence of positive results bias in the field of ophthalmology.

GENIES: a natural-language processing system for the extraction of molecular pathways from journal articles

Systems that extract structured information from natural language passages have been highly successful in specialized domains. The time is opportune for developing analogous applications for molecular biology and genomics. We present a system, GENIES, that extracts and structures information about cellular pathways from the biological literature in accordance with a knowledge model that we developed earlier. We implemented GENIES by modifying an existing medical natural language processing system, MedLEE, and performed a preliminary evaluation study. Our results demonstrate the value of the underlying techniques for the purpose of acquiring valuable knowledge from biological journals.

A knowledge model for the interpretation and visualization of NLP-parsed discharged summaries

At our institution, a Natural Language Processing (NLP) tool called MedLEE is used on a daily basis to parse medical texts including complete discharge summaries. MedLEE transforms written text into a generic structured format, which preserves the richness of the underlying natural language expressions by the use of concept modifiers (like change, certainty, degree and status). As a tradeoff, extraction of application-specific medical information is difficult without a clear understanding of how these modifiers combine. We report on a knowledge model for MedLEE modifiers that is helpful for a high level interpretation of NLP data and is used for the generation of two distinct views on NLP-parsed discharge summaries: A physician view offering a condensed overview of the severity of patient problems and a data mining view featuring binary problem states useful for machine learning.

Using BLAST for identifying gene and protein names in journal articles

We describe a system which automatically identifies gene and protein names in journal articles, an important and non-trivial first step in knowledge extraction of protein and gene actions. Our system uses a database of gene and protein names and is based on BLAST [Altschul et al., Nucleic Acids Res. 25 (1997) 3389-3402], a popular tool for DNA and protein sequence comparison. We describe a method that consists of mapping sequences of text characters into sequences of nucleotides that can be processed by BLAST. We demonstrate that this approach is feasible: the system matches gene and protein names with a recall of 78.8% and a precision of 71.7%, which includes names that are not part of the system database. An analysis of the results suggests techniques that can be used to improve performance further.

A knowledge model for analysis and simulation of regulatory networks

MOTIVATION

In order to aid in hypothesis-driven experimental gene discovery, we are designing a computer application for the automatic retrieval of signal transduction data from electronic versions of scientific publications using natural language processing (NLP) techniques, as well as for visualizing and editing representations of regulatory systems. These systems describe both signal transduction and biochemical pathways within complex multicellular organisms, yeast, and bacteria. This computer application in turn requires the development of a domain-specific ontology, or knowledge model.

RESULTS

We introduce an ontological model for the representation of biological knowledge related to regulatory networks in vertebrates. We outline a taxonomy of the concepts, define their 'whole-to-part' relationships, describe the properties of major concepts, and outline a set of the most important axioms. The ontology is partially realized in a computer system designed to aid researchers in biology and medicine in visualizing and editing a representation of a signal transduction system.

Serum angiotensin-converting-enzyme in rabbits with and without pulmonary granulomatosis. Granulomatosis induced with complete-Freund's-adjuvant or BCG

An animal model with pulmonary, non-caseating, granulomatosis was successfully reproduced in rabbits utilizing intravenous injections of complete-Freund's-adjuvant (CFA) or BCG. Granuloma formation from CFA injections was limited to the lungs, but BCG injections caused systemic granulomatosis (lung, liver and spleen) irrespective of whether the BCG was dissolved in saline or in incomplete-Freund's-adjuvant (IFA). Serum angiotensin-converting-enzyme (ACE) levels began to rise approximately 15 days following the intravenous injection of CFA, but similar rises following the injection of IFA without granuloma formation suggest that the ACE rise was not necessarily reflective of granuloma formation in rabbits. BCG in saline caused no rise in serum ACE, but when suspended in IFA the ACE rise was comparable to that resulting from IFA alone. However, the ACE level of broncho-alveolar-lavage cells obtained from rabbits 21 days post-injection of CFA was 7-fold higher than that of lavaged cells obtained 42 days post injection, correlating with an acute alveolitis occurring early during granuloma formation. These studies confirm the usefulness of intravenous injections of CFA or BCG for inducing a granulomatous state, but show that the assay of serum ACE is not useful for reflecting the granulomatous state in rabbits. In addition, serum ACE levels are 2-5 X higher in rabbits than in humans and tend to fluctuate spontaneously following delivery of the animals to the laboratory.

Pseudoclubbing in a patient with sarcoidosis of the phalangeal bones

We treated a patient who had sarcoidosis with pseudoclubbing. The involvement was asymmetric and involved some fingertips more than others. It did not involve the toes. The pseudoclubbing totally disappeared with effective prednisone therapy. Roentgenograms of the hands showed bone cysts of the distal and middle phalanges, and a gallium citrate Ga 67 scan showed uptake in two of the phalanges. We believe the pseudoclubbing in this patient is a manifestation of phalangeal bone involvement by sarcoidosis with associated dactylitis. A literature review indicates that true clubbing can exist in patients with sarcoidosis, but this case indicates that it must be distinguished from dactylitis.

Accelerated clearance of small solutes from the lungs in interstitial lung disease

Solutions of 99mTc-diethylenetriaminepenta-acetate (99mTc-DTPA) and 99mTcO-4 were aerosolized and inhaled by subjects seated against a scintillation camera. Initial clearance rates of these radionuclides were determined over 6 posterior lung regions. Clearance of 99mTcO-4 (molecular weight, 163 dalton exceeded that of 99mTc-DTPA (molecular weight, 492 daltons) by an average factor of 3.3. Upper-lobe clearance of both radionuclides was greater than lower-lobe clearance in the normal subjects, but this gradient was abolished when the subjects exhaled against 7 cm of positive end-expiratory pressure. Twenty-one patients with clinical and roentgenographic evidence of interstitial lung disease (ILD) and diminished CO diffusion rates were studied with 99mTc-DTPA. Clearance of 99mTc-DTPA was increased in each of 5 patients with idiopathic pulmonary fibrosis, 4 of 8 with sarcoid, 2 of 5 with pneumoconiosis, and 2 of 3 patients with other forms of ILD. In contrast, the clearance of 99mTcO-4 was decreased in 4 patients with pulmonary alveolar proteinosis. Furthermore, no increase in 99mTc-DTPA clearance was found in 5 patients with chronic obstructive pulmonary disease. These studies suggest that the initial clearance of these aerosolized hydrophilic radionuclides is accomplished in part by diffusion through the epithelium of alveoli and respiratory bronchioles. Whereas radionuclide clearance is impaired by the presence of precipitated protein in these structures in pulmonary alveolar proteinosis, clearance is accelerated in ILD. This may indicate increased epithelial permeability in ILD related to injury and increased retractile forces.

Dynamic imaging of the systemic perfusion of a lung cancer: case report

Dynamic lung circulation scintigraphy employing intravenously administered 99mTc as pertechnetate was used to visualize the pulmonary arterial and systemic arterial circulations in a patient with bronchogenic carcinoma. Computer-processed dynamic images and region-of-interest data were utilized to demonstrate differences between tumor and normal regions regarding pulmonary and systemic blood supplies.