Measurement of proptosis using computed tomography based three-dimensional reconstruction software in patients with Graves' orbitopathy

Computed tomography and magnetic resonance imaging approaches to Graves' ophthalmopathy: a narrative review

Graves' ophthalmopathy (GO) affects up to 50% of patients with Graves' disease (GD) ranging from mild ocular irritation to vision loss. The initial diagnosis is based on clinical findings and laboratory tests. Orbital imaging, such as magnetic resonance imaging (MRI) and computed tomography (CT), is an important tool to assess orbital changes, being also useful for understanding disease progression and surgical planning. In this narrative review, we included 92 studies published from 1979 to 2020 that used either MRI and/or CT to diagnose and investigate GO, proposing new methods and techniques. Most of the methods used still need to be corroborated and validated, and, despite the different methods and approaches for thyroid eye disease (TED) evaluation, there is still a lack of standardization of measurements and outcome reports; therefore, additional studies should be performed to include these methods in clinical practice, facilitating the diagnosis and approach for the treatment of TED.

Application of Multiparameter Quantitative Magnetic Resonance Imaging in the Evaluation of Graves' Ophthalmopathy

BACKGROUND

Assessment of the activity of Graves' ophthalmopathy (GO) is difficult. Existing methods need improvement.

PURPOSE

Investigate the application of multiparametric magnetic resonance imaging (MRI) in GO.

STUDY TYPE

Retrospective.

POPULATION

A total of 235 GO patients (age: 38.8 ± 13.4 years; 90 male; 96 active patients).

FIELD STRENGTH/SEQUENCE

Short-tau inversion recovery (STIR) fast spin echo, multiecho spin echo T2 mapping and 3D T1-weighted fast field echo sequences at 3.0 T.

ASSESSMENT

Two physicians assessed the mean and maximum signal intensity ratio of extraocular muscles to white matter (SIR), T2 relaxation time (T2RT), extraocular muscle area (EMA), fat fraction (FF), retrobulbar fat volume (RFV), and extraocular muscle volume (EMV). Clinical activity score (CAS) ≧ 3 was in active stage.

STATISTICAL TESTS

The optimal cut-off point of diagnostic efficacy was selected using receiver operating characteristic (ROC) curve analysis and evaluated using area under the curve (AUC), compared using Student's t test, analysis of variance or Kruskal-Wallis H test. The correlation used Pearson correlation analysis. The discriminant equation used a binary logistic regression analysis. P < 0.05 was considered statistically significant.

RESULTS

The SIRmean, SIRmax, T2RTmean, T2RTmax, EMA, and EMV in active GO patients were significantly higher than those in inactive and were positively correlated with CAS (r = 0.276, 0.228, 0.438, 0.388, 0.502, and 0333, respectively). The FFmax of active patients was significantly lower than that of inactive patients and was negatively correlated with CAS (r = -0.44). Logistic regression analysis indicated that T2RTmean was independently associated with GO active periods and had good diagnostic performance (area under ROC curve = 0.736, sensitivity 70.7%, specificity 69.3%). T2RTmean ≧ 74.295 could be a diagnostic cut-off for judging GO activity (sensitivity 55.3%).

CONCLUSION

SIR, T2RT, EMV, and FF can quantitatively assess the activity and severity of GO and can potentially provide a basis for clinical judgment and selection of treatment options.

EVIDENCE LEVEL

4.

TECHNICAL EFFICACY

Stage 2.

Neural network application for assessing thyroid-associated orbitopathy activity using orbital computed tomography

This study aimed to propose a neural network (NN)-based method to evaluate thyroid-associated orbitopathy (TAO) patient activity using orbital computed tomography (CT). Orbital CT scans were obtained from 144 active and 288 inactive TAO patients. These CT scans were preprocessed by selecting eleven slices from axial, coronal, and sagittal planes and segmenting the region of interest. We devised an NN employing information extracted from 13 pipelines to assess these slices and clinical patient age and sex data for TAO activity evaluation. The proposed NN's performance in evaluating active and inactive TAO patients achieved a 0.871 area under the receiver operating curve (AUROC), 0.786 sensitivity, and 0.779 specificity values. In contrast, the comparison models CSPDenseNet and ConvNeXt were significantly inferior to the proposed model, with 0.819 (p = 0.029) and 0.774 (p = 0.04) AUROC values, respectively. Ablation studies based on the Sequential Forward Selection algorithm identified vital information for optimal performance and evidenced that NNs performed best with three to five active pipelines. This study establishes a promising TAO activity diagnosing tool with further validation.

Hertel-exophthalmometry-like multi-detector-row-CT-exophthalmometry: inter-disciplinary inter-observer reproducibility of measurements

OBJECTIVES

To investigate the interdisciplinary interobserver reproducibility of Hertel-exophthalmometry-like protrusion measurements on multidetector-row-computed-tomography- (MDCT-) images of the orbit to facilitate structured evaluation of the orbit and mid-face.

METHODS

Respective reproducibility of base-length along the interfronto-zygomatic line, right and left ocular protrusion, and deriving interocular difference was measured in this retrospective (04/2009-03/2020) single-centre observational study. MDCT-series and slice-positions were selected independently, using picture-archiving-and-communication-system- (PACS-) tools on tilt-corrected axial MDCT-images (slice-thickness 0.6-3.0 mm, window/centre 350/50 HU) in 37 selected adult patients (24 female, age 57 ± 13 years, average±standard-deviation) with clinical indication for Hertel-exophthalmometry, by one radiology-attending, two ophthalmology-attendings, one critical-care-attending, and one ear-nose-throat-surgery resident, respectively. Bland-Altman plots and Wilcoxon-matched-pairs-signed-rank-tests compared interobserver results.

RESULTS

Mean and median interobserver and intraobserver (radiology-attending) deviations were within 1 mm of respective averages of base-length (98 ± 4 mm), right and left ocular protrusion (21 ± 4 mm) and interocular difference (2 ± 1 mm). Relative interobserver deviations were within 2.0% of average (all patients) for base-length, and 5.0% (>80% of patients) for ocular protrusion. Pairwise interobserver comparison showed no significant differences between interocular differences of protrusion.

CONCLUSIONS

Respective measurements of base-length, ocular protrusion, and deriving interocular difference show high interdisciplinary interobserver reproducibility in tilt-corrected axial MDCT-images of the orbit or mid-face.

ADVANCES IN KNOWLEDGE

Hertel-exophthalmometry-like protrusion measurements did not depend on the years of experience or the medical subspecialty of the observer. Measurements are objective, well reproducible and important for multiple medical disciplines and should thus be included in pertinent radiology reports.

Automatic measurement of exophthalmos based orbital CT images using deep learning

Introduction: Objective, accurate, and efficient measurement of exophthalmos is imperative for diagnosing orbital diseases that cause abnormal degrees of exophthalmos (such as thyroid-related eye diseases) and for quantifying treatment effects. Methods: To address the limitations of existing clinical methods for measuring exophthalmos, such as poor reproducibility, low reliability, and subjectivity, we propose a method that uses deep learning and image processing techniques to measure the exophthalmos. The proposed method calculates two vertical distances; the distance from the apex of the anterior surface of the cornea to the highest protrusion point of the outer edge of the orbit in axial CT images and the distance from the apex of the anterior surface of the cornea to the highest protrusion point of the upper and lower outer edges of the orbit in sagittal CT images. Results: Based on the dataset used, the results of the present method are in good agreement with those measured manually by clinicians, achieving a concordance correlation coefficient (CCC) of 0.9895 and an intraclass correlation coefficient (ICC) of 0.9698 on axial CT images while achieving a CCC of 0.9902 and an ICC of 0.9773 on sagittal CT images. Discussion: In summary, our method can provide a fully automated measurement of the exophthalmos based on orbital CT images. The proposed method is reproducible, shows high accuracy and objectivity, aids in the diagnosis of relevant orbital diseases, and can quantify treatment effects.

Total thyroidectomy for giant nodular goiter guided by pre-operative 3D computed tomography reconstruction and 3D printing: A case report

BACKGROUND

Nodular goiter is a common clinical problem, and thyroidectomy is preferred in patients with obstructive symptoms. Thyroidectomy is a complex procedure with some common complications. Three-dimensional (3D) computed tomography (CT) reconstruction and 3D printing provide visualized 3D anatomical structure, posing an enormously valuable potential in precise surgery with optimal efficacy and minimum complications. Here, we aimed to perform a precise thyroidectomy guided by this technology.

METHODS

The patient was an 80-year-old woman with 10 years of goiter, 1 year of labored dyspnea, and a history of thyroid surgery 62 years ago. In addition to ultrasonography examination, CT images were obtained to construct the 3D model to identify the 3D relationship between the lesion and adjacent structures, and a 3D model of the trachea was created and printed using a 3D printer.

RESULTS

The 3D model clearly presented the diffuse enlargement of the two lobes and isthmus and the compression of the goiter. Under the 3D guidance, the operative resection specimen of the right lobe and isthmus was 12 ´ 7 ´ 5 cm, whereas the left lobe specimen was 12 ´ 9 ´ 6 cm. Nodular goiter and lymphocytic thyroiditis were confirmed by postoperative histopathology. There were no complications after total thyroidectomy except for non-permanent hypocalcemia and hypoparathyroidism.

CONCLUSION

Our results proved that total thyroidectomy for giant goiter is challenging, and 3D image-guided thyroidectomy facilitates precise and safe resection with fewer complications. 3D CT reconstruction and 3D printing can provide anatomical details and may be considered in thyroidectomy planning for patients with giant goiter.

Fall from bed resulting in emergent lateral orbital canthotomy…7 days later

Orbital compartment syndrome is an ophthalmologic emergency that requires immediate intervention to preserve eyesight. This case highlights a rare, delayed presentation of orbital compartment syndrome requiring emergent lateral orbital canthotomy.

Retina-like Imaging and Its Applications: A Brief Review

The properties of the human eye retina, including space-variant resolution and gaze characters, provide many advantages for numerous applications that simultaneously require a large field of view, high resolution, and real-time performance. Therefore, retina-like mechanisms and sensors have received considerable attention in recent years. This paper provides a review of state-of-the-art retina-like imaging techniques and applications. First, we introduce the principle and implementing methods, including software and hardware, and describe the comparisons between them. Then, we present typical applications combined with retina-like imaging, including three-dimensional acquisition and reconstruction, target tracking, deep learning, and ghost imaging. Finally, the challenges and outlook are discussed to further study for practical use. The results are beneficial for better understanding retina-like imaging.

A new radiological measurement method used to evaluate the modified transconjunctival orbital fat decompression surgery

Purpose

A new radiological method was used to evaluate the plastic effect of modified transconjunctival orbital fat decompression surgery in patients with inactive thyroid-associated ophthalmopathy.

Methods

In this study, 10 inactive patients (14 eyes) with moderate to severe thyroid-associated ophthalmopathy were selected. The patients underwent modified transconjunctival orbital fat decompression surgery. According to the results of a spiral CT scan before and 6 months after the surgery, the INFINITT system workstation was used to measure the eyeball protrusion value. According to the results obtained by the PHLIPS IntelliSpace Portal elliptical area and line segment measurement tools, the standard elliptical vertebral volume formula was used to calculate the muscular cone inner volume. Changes in eyeball protrusion and the inner volume of the muscular cone before and after surgery were examined. Statistical analysis of the correlation between the two parameters was performed.

Results

Radiological measurement results confirmed that removing the orbital fat in the muscle cone during surgery was effective for alleviating eyeball protrusion in patients with thyroid-associated ophthalmopathy (P < 0.05). This surgery caused an obvious change in the muscle cone inner volume (P < 0.05). And there was significant correlation between changes in eyeball protrusion and muscle cone inner volume (r = 0.797, P = 0.0006, P < 0.05).

Conclusion

The radiological assessment method used in this study is simple and easy to implement. For inactive patients with moderate to severe thyroid-associated ophthalmopathy who just want to improve their appearance, the modified orbital fat decompression surgery is worth considering.