Comparison of Haller index values calculated with chest radiographs versus CT for pectus excavatum evaluation

Utility of White Light Scanning as an Alternative to Computed Tomography to Evaluate Severity of Pectus Excavatum Deformity

BACKGROUND

Pectus excavatum (PE) severity and surgical candidacy are determined by computed tomography (CT)-delineated Haller Index (HI) and Correction Index (CI). White light scanning (WLS) has been proposed as a non-ionizing alternative. The purpose of this retrospective study is to create models to determine PE severity using WLS as a non-ionizing alternative to CT.

METHODS

Between November 2015 and February 2023, CT and WLS were performed for children ≤18 years undergoing evaluation at a high-volume, chest-wall deformity clinic. Separate quadratic discriminate analysis models were developed to predict CT HI ≥ 3.25 and CT CI ≥ 28% indicating surgical candidacy. Two bootstrap forest models were trained on WLS measurements and patient demographics to predict CT HI and CT CI values then compared to actual index values by intraclass correlation coefficient (ICC).

RESULTS

In total, 242 patients were enrolled (86.4% male, mean [SD] age 15.2 [1.3] years). Quadratic discriminate analysis models predicted CT HI ≥ 3.25 with specificity = 91.7%, PPV = 97.7% (AUC = 0.91), and CT CI ≥ 28% with specificity = 92.3%, PPV = 93.5% (AUC = 0.84). Bootstrap forest model predicted CT HI with training dataset ICC (95% CI) = 0.91 (0.88-0.93, R2 = 0.85) and test dataset ICC (95% CI) = 0.86 (0.71-0.94, R2 = 0.77). For CT CI, training dataset ICC (95% CI) = 0.91 (0.81-0.93, R2 = 0.86) and test dataset ICC (95% CI) = 0.75 (0.50-0.88, R2 = 0.63).

CONCLUSIONS

Using noninvasive and nonionizing WLS imaging, we can predict PE severity at surgical threshold with high specificity obviating the need for CT. Furthermore, we can predict actual CT HI and CI with moderate-excellent reliability. We anticipate this point-of-care tool to obviate the need for most cross-sectional imaging during surgical evaluation of PE.

LEVEL OF EVIDENCE

Level III.

STUDY TYPE

Study of Diagnostic Test.

Is chest radiography a valid alternative to computed tomography in evaluation of pectus excavatum?

BACKGROUND

Current pectus excavatum management includes a computed tomography scan to evaluate the correction index, whose superiority to the Haller Index in terms of specificity and sensibility is still under debate. Furthermore, several studies report interchangeability between the Haller Index as measured by computed tomography and as measured by X-radiograph; however, it is not clear whether this correlation also exists for the correction index. The aim of our study was to evaluate the correlation between measurements of the Haller Index and the correction index obtained by Computed Tomography and by X-radiograph.

METHODS

This prospective study included 31 patients with pectus excavatum (who underwent preoperative chest computed tomography and X-radiograph) and a control group of 31 patients (who presented no chest deformity and underwent the same exams for other unrelated causes). We measured Haller Index and correction index on both exams for both groups. To demonstrate any correlation between computed tomography scans and X-radiographs for the two indexes, the Pearson R correlation test, Bland-Altman analysis, and ANOVA nested test were performed.

RESULTS

Pearson's coefficient (0.829 with P<0.0001) and ANOVA nested test showed a significant correlation and similar results between the Haller Index and the correction index on computed tomography and on X-radiograph.

CONCLUSIONS

Significant correlation and similar results are shown in our study in the measurement of CI and HI on computed tomography and X-radiograph. Further studies including a larger number of patients may be warranted.

Serratus Anterior Plane Block: A Better Modality of Pain Control after Pectus Excavatum Repair

Background

Postoperative pain management following minimally invasive repair of pectus excavatum (MIRPE) remains a critical concern due to severe post-procedural pain. Promising results have been reported for cryoanalgesia following MIRPE; however, its invasiveness, single-lung ventilation, and additional instrumentation requirements remain obstacles. Serratus anterior plane block (SAPB) is a regional block technique capable of covering the anterior chest wall at the T2-9 levels, which are affected by MIRPE. We hypothesized that SAPB would be a superior alternative pain control modality that reduces postoperative pain more effectively than conventional methods.

Methods

We conducted a retrospective study of patients who underwent MIRPE between March 2022 and August 2023. The efficacy of pain control was compared between group N (conventional pain management, n=24) and group S (SAPB, n=26). Group N received intravenous patient-controlled analgesia (IV-PCA) and subcutaneous local anesthetic infusion. Group S received bilateral continuous SAPB with 0.3% ropivacaine after a bilateral bolus injection of 30 mL of 0.25% ropivacaine with baseline IV-PCA. Pain levels were evaluated using a Visual Analog Scale (VAS) at 1, 3, 6, 12, 24, 48, and 72 hours postoperatively and total intravenous rescue analgesic consumption by morphine milligram equivalents (MME).

Results

Mean VAS scores were significantly lower in group S than in group N throughout the 72-hour postoperative period (p<0.01). Group S showed significantly lower MME at postoperative 72 hours (group N: 108.53, group S: 16.61; p<0.01).

Conclusion

SAPB improved immediate postoperative pain control in both the resting and dynamic states and reduced opioid consumption compared to conventional management.

Outcomes of the Nuss procedure in children with pectus excavatum: 14 years of experience

BACKGROUND

We aimed to assess the effectiveness of the Nuss procedure for pectus excavatum (PE) and explore the impacts of sex and age on outcomes.

METHODS

We retrospectively reviewed 594 consecutive children ≤18 years of age who underwent the thoracoscopy-assisted Nuss technique between January 2006 and July 2019. The severity of pectus deformity was calculated according to the Haller index (HI). The classification of PE and clinical data including complications was analyzed.

RESULTS

Of the 594 patients, 456 (76.8%) were boys and 138 (23.2%) were girls. The mean age at surgery was 10.0 ± 5.0 years. The most common types of PE were 1A and 2A2 according to Park classification. Intraoperative and postoperative complication rates were 2/594 (0.3%) and 74/594 (12.5%), respectively. The most common complication was bar displacement. The bar was removed in 414 patients 3.5 ± 0.8 years later. The mean preoperative HI, postoperative HI with bar, and HI after bar removal were 4.2 ± 1.7, 2.4 ± 0.3, and 2.7 ± 0.5, respectively. Compared to the preoperative HI, both the postoperative HI with bar and HI after bar removal were significantly lower ( p < 0.001). For preschool-age children, the preoperative HI was significantly higher ( p = 0.027) and the change in HI significantly improved compared to school-age children ( p = 0.004). Boys and adolescents needed significantly more bars and stabilizers.

CONCLUSION

Surgical correction of PE using the Nuss procedure is a safe procedure and improves the HI in children of different ages, even in those younger than 6 years of age.

Pectus Excavatum: Consensus and Controversies in Clinical Practice

BACKGROUND

Pectus excavatum is the most common congenital anterior chest wall deformity. Currently, a wide variety of diagnostic protocols and criteria for corrective surgery are being used. Their use is predominantly based on local preferences and experience. To date, no guideline is available, introducing heterogeneity of care as observed in current daily practice. The aim of this study was to evaluate consensus and controversies regarding the diagnostic protocol, indications for surgical correction, and postoperative evaluation of pectus excavatum.

METHODS

The study consisted of 3 consecutive survey rounds evaluating agreement on different statements regarding pectus excavatum care. Consensus was achieved if at least 70% of participants provided a concurring opinion.

RESULTS

All 3 rounds were completed by 57 participants (18% response rate). Consensus was achieved on 18 of 62 statements (29%). Regarding the diagnostic protocol, participants agreed to routinely include conventional photography. In the presence of cardiac impairment, electrocardiography and echocardiography were indicated. Upon suspicion of pulmonary impairment, spirometry was recommended. In addition, consensus was reached on the indications for corrective surgery, including symptomatic pectus excavatum and progression. Participants moreover agreed that a plain chest radiograph must be acquired directly after surgery, whereas conventional photography and physical examination should both be part of routine postoperative follow-up.

CONCLUSIONS

Through a multiround survey, international consensus was formed on multiple topics to aid standardization of pectus excavatum care.

Co-existing obstructive sleep apnea reduces Nuss surgery efficacy in pectus excavatum

Nuss surgery is effective in correcting pectus excavatum (PE), with a recurrence rate of 1.2–27%. Re-do surgery is successful but still has a 6% failure rate. Patients with obstructive sleep apnea (OSA) experience repetitive PE-associated sternal depression during sleep. As the prevalence of OSA among PE patients is higher than the average, co-existing OSA in PE patients might negatively affect the efficacy of Nuss surgery. This study aimed to evaluate the impact of co-existing OSA on Nuss surgery in patients with PE. In total, 20 adult patients with PE only and 9 patients with PE and OSA were analyzed. Polysomnography was performed before Nuss surgery to evaluate OSA. Sternovertebral distance (SVD) and radiographic Haller index (RHI) were recorded before surgery and at 3, 6, and 24 months postoperatively. The results showed that percentage changes in SVD in patients with PE only at 3, 6, and 24 months postoperatively were significantly increased compared with those in the patients with PE and OSA (31.1% vs. 14.1% at 3 months; 37.5% vs. 21.4% at 6 months; 42.5% vs. 19.2% at 24 months). Meanwhile, percentage changes in RHI were significantly lower in patients with PE alone than in the patients with PE and OSA (-22.9% vs. -9.3% at 3 months; -27.9% vs. -18.7% at 6 months; -30.6% vs. -16.7% at 24 months). This study showed that co-existing OSA might reduce the efficacy of Nuss surgery for patients with PE. We recommend that patients with PE should be evaluated and treated for OSA before surgery to prevent surgical failure after bar removal.

Visual diagnosis of pectus excavatum: An inter-observer and intra-observer agreement analysis

BACKGROUND/PURPOSE

Among patients suspected of pectus excavatum, visual examination is a key aspect of diagnosis and, moreover, guides work-up and treatment strategy. This study evaluated the inter-observer and intra-observer agreement of visual examination and diagnosis of pectus excavatum among experts.

METHODS

Three-dimensional surface images of consecutive patients suspected of pectus excavatum were reviewed in a multi-center setting. Interactive three-dimensional images were evaluated for the presence of pectus excavatum, asymmetry, flaring, depth of deformity, cranial onset, overall severity and morphological subtype through a questionnaire. Observers were blinded to all clinical patient information, completing the questionnaire twice per subject. Agreement was analyzed by kappa statistics.

RESULTS

Fifty-eight subjects with a median age of 15.5 years (interquartile range: 14.1-18.2) were evaluated by 5 (cardio)thoracic surgeons. Pectus excavatum was visually diagnosed in 55% to 95% of cases by different surgeons, revealing considerable inter-observer differences (kappa: 0.50; 95%-confidence interval [CI]: 0.41-0.58). All other items demonstrated inter-observer kappa's of 0.25-0.37. Intra-observer analyses evaluating the presence of pectus excavatum demonstrated a kappa of 0.81 (95%-CI: 0.72-0.91), while all other items showed intra-observer kappa's of 0.36-0.68.

CONCLUSIONS

Visual examination and diagnosis of pectus excavatum yields considerable inter-observer and intra-observer disagreements. As this variation in judgement could impact work-up and treatment strategy, objective standardization is urged.

LEVELS OF EVIDENCE

III.

Finding suitable candidates for vacuum bell therapy in pectus excavatum patients

Vacuum bell therapy has been acceptable substitute for pectus excavatum patients who want to improve their appearance but avoid surgical correction. The aim of this study was to assess the pre-treatment characteristics of patients with pectus excavatum and to establish characteristics that can potentially help identify ideal candidates for vacuum bell therapy. Expected improvements in thoracic indices were evaluated using pre-treatment chest computed tomography, which was performed before and after applying a vacuum bell device. Treatment results after 1-year of application were evaluated using changes in the Haller index before and after treatment. The patients were categorized into two groups according the post- treatment changes in Haller index calculated using chest radiographs: those with changes in Haller index less than 0.5 (Group 1) and those with greater than or equal to 0.5 (Group 2). Pre-treatment Haller index was significantly lower in Group 1 than in Group 2 (3.1 ± 0.46 vs. 4.2 ± 1.14, respectively, p < 0.001). The expected improvement in Haller index in Group 2 was significantly higher than that in Group 1 (3.3 ± 0.60 vs. 2.8 ± 0.54, respectively, p = 0.001). The cut-off value of the expected improvement in Haller index was 0.46 with a sensitivity of 75.8% and a specificity of 83.3%. Patients who demonstrated pliability with a vacuum bell were identified as suitable candidates.

Three-dimensional Surface Imaging for Clinical Decision Making in Pectus Excavatum

To evaluate pectus excavatum, 3-dimensional surface imaging is a promising radiation-free alternative to computed tomography and plain radiographs. Given that 3-dimensional images concern the external surface, the conventional Haller index, and correction index are not applicable as these are based on internal diameters. Therefore, external equivalents have been introduced for 3-dimensional images. However, cut-off values to help determine surgical candidacy using external indices are lacking. A prospective cohort study was conducted. Consecutive patients referred for suspected pectus excavatum received a computed tomography (≥18 years) or plain radiographs (<18 years). The external Haller index and external correction index were calculated from additionally acquired 3-dimensional images. Cut-off values for the 3-dimensional image derived indices were obtained by receiver-operating characteristic curve analyses, using a conventional Haller index ≥3.25, and computed tomography derived correction index ≥28.0% as indicative for surgery. Sixty-one and 63 patients were included in the computed tomography and radiograph group, respectively. To determine potential surgical candidacy, receiver-operating characteristic analyses found an optimum cut-off of ≥1.83 for the external Haller index in both the computed tomography and radiograph group with a positive predictive value between 0.90 and 0.97 and a negative predictive value between 0.72 and 0.81. The optimal cut-off for the external correction index was ≥15.2% with a positive predictive value of 0.86 and negative predictive value of 0.93. The 3-dimensional image derived external Haller index and external correction index are accurate radiation-free alternatives to facilitate surgical decision-making among patients suspected of pectus excavatum with values of ≥1.83 and ≥15.2% indicative for surgery.

Surface topography index: a novel deformity severity assessment index for pectus excavatum

BACKGROUND

The surface topography index (STI) has great potential in both routine computed tomography (CT) scan and emerging optical imaging systems. However, the diagnostic accuracy and stability of the STI as a deformity severity assessment index has not been fully confirmed. Therefore, the aim of the present study was to determine the diagnostic performance of the STI as a novel deformity severity assessment index for pectus excavatum.

METHODS

The present study consisted of 722 chest CT images from a single center. The standard CT index (CTI) and STI were calculated for all patients. The between-group difference and the level of compliance between the CTI and STI was analyzed by t-test and Pearson correlation. The diagnostic value and optimum discriminatory values of the CTI and STI were calculated by a receiver-operating characteristic (ROC) curve and DeLong's test.

RESULTS

The distributions of the CTI and STI were similar and showed a slight overlap between the pectus excavatum (PE) and non-PE groups. Both the CTI and STI significantly differed between the 2 groups (P<0.001). The STI demonstrated a strong Pearson correlation with the CTI (r=0.91, 95% confidence interval: 0.88-0.91, P<0.001). The ROC curves showed that STI =1.58 (sensitivity: 0.93, specificity: 0.95) could be considered equivalent to CTI =2.72 (sensitivity: 0.93, specificity: 0.97) as the optimum discriminatory values. DeLong's test showed no significant difference in the ROC curve results between the CTI and STI (Z=0.90, P=0.37).

CONCLUSIONS

The STI has comparative discrimination ability in PE diagnosis and deformity severity assessment when used with the standard CTI. The STI as a novel index is not only an ideal evaluation metric of PE deformity but also an objective trait for PE patients just as weight and height for everyone.

Anterior chest wall regression after Nuss bar removal in adult patients with pectus excavatum

OBJECTIVE

Pectus excavatum repair with the Nuss procedure can be successfully performed in adults. After removing the pectus bars, the anterior chest wall may regress to some degree. The purpose of this study was to clarify the amount of improvement and regression of the chest wall after bar removal.

METHODS

In 45 adult patients who underwent the Nuss procedure, the sternovertebral distance (SVD) on lateral chest X-ray was measured (A) before the Nuss procedure, (B) before bar removal, and (C) after bar removal. The average SVD was compared, and the difference between A and C suggesting final sternal elevation and B and C suggesting regression was calculated. The correlation between the duration of bar in situ and the amount of regression was analyzed.

RESULTS

The average period of bar in situ was 34.9 ± 5.0 (range 23-45) months. The average SVD-A, SVD-B, and SVD-C values were 58.9 ± 20.0, 89.3 ± 19.1, and 81.6 ± 20.1 mm, respectively, with significant differences among them. Final sternal elevation was 22.7 ± 17.4 mm, and average regression was 7.6 ± 8.6 mm. The correlation coefficient between the duration of bar in situ and the amount of regression was 0.119, suggesting no clear correlation.

CONCLUSIONS

In spite of some degree of chest wall regression after bar removal, the Nuss procedure was effective for adult patients with pectus excavatum. The period of bar in situ and chest wall regression had little correlation.

Application of Polydioxanone Sutures in the Nuss Procedure

BACKGROUND/PURPOSE

 The Nuss procedure is the most common surgical repair for pectus excavatum (PE). Surgical steel wires are used in some modifications of the Nuss procedure to attach one or both ends of a support bar to the ribs. During follow-up, wire breakage was found in some cases. Patients with wire breakage may undergo prolonged bar removal surgery and may be exposed to excessive radiation.In this study, we had a series of patients who received polydioxanone suture (PDS) fixations instead of steel wires. This retrospective study was conducted to explore the differences between these two fixation materials in the incidence of related complications and efficacies. Furthermore, we attempted to observe whether the two materials lead to similar surgical efficacy in the Nuss procedure, whether they have divergent effects on the bar removal surgery, and whether PDS can reduce the risks due to steel wire breakage as expected.

METHODS

 We retrospectively studied PDS and surgical steel wires as fixation materials for the Nuss procedure in children with congenital PE and reviewed the outcomes and complications. A total of 75 children who had undergone Nuss procedure repairs and bar removals from January 2013 to December 2019 were recruited to participate in this study. They were divided into three groups: the PDS group, the unbroken wire (UBW) group, and the broken wire (BW) group, according to the fixation materials and whether the wires had broken or not. Moreover, we selected the duration of operation (DO), intraoperative blood loss (BL), bar displacement (BD), postoperative pain score (PPS), and incision infection as the risk indicators and the postrepair Haller index (HI) as the effectiveness indicator. These indicators were statistically compared to determine whether there were differences among the three groups.

RESULTS

 One BD occurred in the PDS and BW groups while none took place in the UBW group. No incision infection was found in any of the groups. The PDS group had the shortest DO, while the DO in the UBW group was shorter than that in the BW group (p < 0.05). BL in the PDS group was less than that in the other two groups (p < 0.05). Additionally, no difference was observed in BL between the BW and UBW groups (p > 0.05). The PPS of the PDS group was less than that of the BW group (p < 0.05), whereas no differences were found between the other two groups. No statistical difference emerged in HI among the groups (p > 0.05).

CONCLUSION

 PDS fixation results in a similar repair outcome and shows certain advantages in the DO, BL, and PPS; also, PDSs are safe and effective in the Nuss procedure.

LEVEL OF EVIDENCE

 Level III.

Validating 3D indexes in the non-surgical pectus excavatum patient

BACKGROUND/PURPOSE

In recent years there has been an increased interest in three-dimensional (3D) imaging for the assessment of chest wall deformities. Some studies have proven a correlation between 3D and traditional cross-sectional images but only for patients who already had an indication for a computed tomography (CT) scan prior to surgery; mainly due to their severity. Our aim is to determine the accuracy and reliability of the measures obtained by a portable 3D scanner in a cohort of pectus excavatum (PE) patients with different severity grades, as well as in controls.

METHODS

We conducted a study comparing radiological and optical indexes on magnetic resonance imaging (MRI) and 3D surface images. We used a hand-held 3D scanner to obtain the optical Haller Index (3DHI) and Correction Index (3DCI) and a limited MRI scan to obtain the traditional indexes. A statistical analysis was carried out to determine the correlation between optical and radiological measures, plus a subjective severity evaluation.

RESULTS

Twenty-eight patients and controls were enrolled in the study. In both the control and PE groups, there was a significant positive correlation between the indexes, especially for the CI. There were no differences in correlation regarding gender, age or severity. CI appears to better discriminate amongst the different severity groups and controls.

CONCLUSION

3D surface imaging is feasible and appropriate to use to assess PE, regardless of the severity or characteristics of the individual patient. Even with a small hand-held device, we can obtain accurate images and measures which are especially useful for the assessment of the nonsurgical pectus patient.

Recurrence of pectus excavatum in long-term follow-up after the Nuss procedure in young children based on the radiographic Haller index

BACKGROUND/PURPOSE

To show the changes of the thorax after bar removal in young children with pectus excavatum in long-term postoperative follow-up.

METHODS

A total of 173 patients who underwent Nuss procedure under the age of 10 years from January 2005 to December 2013 and underwent bar removal were retrospectively reviewed. Then, Patients who were followed-up for more than 5 years after bar removal were selected and assessed. All patients were evaluated with the Haller index (HI) by chest computed tomography before the Nuss procedure. Follow-up after bar removal was done by two-view radiography. Radiographic HI (rHI) change was evaluated from before bar removal, to immediately after bar removal, and 3 years and 5 years after bar removal.

RESULTS

Forty-two patients (35 boys, 7 girls) were followed-up for more than 5 years after bar removal. The average age at the Nuss procedure was 6.1 ± 1.3 years, and the average HI was 5.07 ± 1.54. The average age at bar removal was 8.5 ± 1.2 years. The average rHI was 2.47 ± 0.33 before bar removal, 2.75 ± 0.50 immediately after bar removal, 3.24 ± 0.64 at 3 years after bar removal, and 3.46 ± 0.91 at 5 years after bar removal. The rHI value increased significantly between all periods.

CONCLUSIONS

The Nuss procedure for young children may have the risk of recurrence during growth after bar removal.

LEVEL OF EVIDENCE

Level IV.

Computer-aided diagnosis of pectus excavatum using CT images and deep learning methods

Pectus excavatum (PE) is one of the most common chest wall defects. Accurate assessment of PE deformities is critical for effective surgical intervention. Index-based evaluations have become the standard for objectively estimating PE, however, these indexes cannot represent the whole information of chest CT images and may associated with significant error due to the individual differences. To overcome these limitations, this paper developed a computer-aided diagnosis (CAD) system based on the convolutional neural network (CNN) to automatically learn discriminative features and classify PE images. We also adopted block-wise fine-tuning methods based on the transfer learning strategy to reduce the potential risk of overfitting caused by limited data and experimentally explored the best fine-tuning degree. Our method achieved a high level of classification accuracy with 94.76% for PE diagnosis. Furthermore, we proposed a majority rule-based voting method to provide a comprehensively diagnostic results for each patient, which integrated the classification results of the whole thorax. The promising results support the feasibility of our proposed CNN-based CAD system for automatic PE diagnosis, which paves a way for comprehensive assessments of PE in clinics.

Usefulness of 3-Dimensional Body Surface Scanning in the Evaluation of Patients with Pectus Carinatum

Background

Radiographic modalities have been commonly used to evaluate pectus carinatum (PC), and compressive orthotic bracing is the most widely accepted treatment method. The aim of this study was to determine the efficacy of 3-dimensional (3D) body surface scanning as an alternative modality for the evaluation of PC.

Methods

The medical records of 63 patients with PC who were treated with compressive orthotic bracing therapy between July 2017 and February 2019 were retrospectively analyzed. Using both 2-view chest radiography (posteroanterior and lateral view) and 3D body scanning, the height of maximal protrusion of the chest wall was measured both before and after 2 weeks of bracing therapy. The difference between the pre- and post-treatment measurements was calculated for both modalities, and these differences were compared and analyzed.

Results

Based on the comparison between the pre- and post-treatment radiographs, bracing therapy produced favorable outcomes in all patients (p<0.001). The measurements obtained via 3D scanning were strongly correlated with those obtained via chest radiography (r=0.60).

Conclusion

Based on the findings of this study, 3D body surface scanning appears to be an effective, radiation-free, and simple method for the post-treatment follow-up evaluation of PC, and thus can be considered an alternative to radiography.

Chest X-ray Dose Equivalent Low-dose CT with Tin Filtration: Potential Role for the Assessment of Pectus Excavatum

RATIONALE AND OBJECTIVES

To determine the value of chest CT with tin filtration applying a dose equivalent to chest x-ray for the assessment of the Haller index for evaluation of pectus excavatum.

MATERIALS AND METHODS

Two hundred seventy-two patients from a prospective single center study were included and underwent a clinical standard dose chest CT (effective dose 1.8 ± 0.7 mSv) followed by a low-dose CT (0.13 ± 0.01 mSv) in the same session. Two blinded readers independently evaluated all data sets. Image quality for bony chest wall assessment was noted. Radiologists further assessed (a) transverse thoracic diameter, (b) anteroposterior thoracic diameter, and calculated (c) Haller index by dividing transverse diameter by anteroposterior diameter. The agreement of both readers in standard dose and low-dose CT was assessed using Lin's concordance correlation coefficient (p_c).

RESULTS

Subjective image quality was lower for low dose compared to standard dose CT images by both readers (p < 0.001). In total, 99% (n = 540) of low-dose CT scans were rated as diagnostic for bony chest wall assessment by both readers. There was a high agreement for assessment of transverse diameter, anteroposterior diameter and Haller index comparing both readers in standard dose and low-dose CT with p_c values indicating substantial agreement (i.e., 0.95> and ≤0.99) in 12/18 (67%) and almost perfect agreement (i.e., >0.99) in 6/18 (33%).

CONCLUSION

Our study suggests that low-dose CT with tin filtration applying a radiation dose equivalent to a plain chest X-ray is excellent for assessing the Haller index.

The medial breast margin sign: A new sign of pectus excavatum in adult females and comparison with classic signs

INTRODUCTION

Pectus excavatum (PX) denotes a concavity of the sternum and is the most common chest wall deformity. Many characteristic signs have been described on frontal chest radiographs including increased density of the inferomedial right lung, blurring of the right heart border, steeply angled anterior ribs, horizontal posterior ribs, straight or convex left heart border and loss of silhouette of the descending thoracic aorta. These signs are often subtle and rarely all present in any individual. We describe a further sign in women with PX, the medial breast margin sign. This sign consists of more sharply defined and more vertically oriented medial breast borders on frontal chest radiographs than in those of women with normal chest wall morphology. This study aims to document the sensitivity, specificity and inter-observer reliability of the new sign, and compare with that of the previously described signs in patients with varying degrees of PX.

METHODS

The frontal chest radiographs of 185 women with PX and 50 women with normal chest wall morphology were assessed by two reviewers for the presence of the new sign and previously described signs. All the signs had their sensitivity, specificity and inter-observer reliability calculated.

RESULTS

The new sign had a sensitivity of 0.48, a specificity of 0.96 and inter-observer reliability of κ = 0.79, ranking third, second and first among all other signs, respectively.

CONCLUSION

The medial breast margin sign is useful in diagnosing PX and is comparable to the previously described classic signs.

Effect of internal fixation of the sternum using bioabsorbable pins in small children

OBJECTIVES

A sternal pin can be used to internally fix the reapproximated sternum after midline sternotomy. This paper will evaluate the effectiveness of using a sternal pin in small children by means of a computer tomography scan.

METHODS

Propensity score matching was performed for patients undergoing a first-time median sternotomy from April 2012 to December 2014 with a follow-up computer tomography scan after 6 months. Seventeen matched patients were selected for both the control and the sternal pin groups. The angle of the sternal reflection at the joint surface was measured by computer tomography scan. In addition, the Haller index was measured at each thoracic vertebral level.

RESULTS

The angle of the sternal reflection was more variable in the control group compared with the sternal pin group: the standard deviation was 31.6° for the control group and 10.2° for the sternal pin group (P value = .0009). Seven out of 17 patients in the control group had a negative angle (excavated sternum) compared with 1 out of 17 in the sternal pin group (P = .0391). In the other patients, the angle was 23.9° ± 3.6° in the control group and 10.1 ± 2.8 in the sternal pin group (P = .0061). The Haller index was also more variable in the control group, and it was significantly different from the sternal pin group at the ninth vertebral level (P = .0409).

CONCLUSIONS

The study demonstrated that the use of a sternal pin was associated with decreased variation in the sternal angles and decreased incidence and severity of sternal protrusion and excavation in small children.

A novel technique to measure severity of pediatric pectus excavatum using white light scanning

BACKGROUND/PURPOSE

Computed tomography (CT) derived Haller Index (HI) remains the standard for quantifying severity in patient with pectus excavatum (PE). Optical scanning described in literature reports optimistic results and new indices that correlate with HI. This study assessed the feasibility of a handheld White Light Scanner (WLS) to obtain 3D measurements and indices of PE deformity.

METHODS

From April 2015-April 2017, WLS scanning was conducted by orthotists during clinical visits. Included were children with PE up to 18 years. Analysis assessed correlation of a WLS-derived severity index, Hebal-Malas Index (HMI), with physician measured PE Depth (PED), and CT-derived HI.

RESULTS

Of 195 participants, 185(94%) patients with PE were scanned and 127(69%) had complete WLS data. For 88 patients undergoing monitoring, HMI correlated with PED (r = 0.42, p = 0.004). For 39 patients with pre-operative CT, HMI demonstrated strong correlation with HI (r = 0.87, p<0.0001).

CONCLUSIONS

WLS demonstrated high feasibility of scanning PE. WLS-derived HMI best correlates with HI for patients with severe pectus deformity. Our current data is suggestive that WLS is best applied for severe deformities and yet to be established for milder deformities. Future yearly WLS will provide data on deformity progression and surgical therapy.

LEVEL OF EVIDENCE

IV.

TYPE OF STUDY

Diagnostic Study.

Disorders of the Chest Wall: Clinical Manifestations

Chest wall disorders represent deformities and/or injuries that alter the rib cage geometry and result in pulmonary restriction, increased work of breathing, exercise limitations, and cosmotic concerns. These disorders are congenital or acquired and affect all ages. Disorders affecting the spine (kyphoscoliosis, ankylosing spondylitis), ribs (flail chest), and sternum (pectus excavatum) are discussed in this article, with emphasis on clinical presentations, pulmonary function abnormalities, diagnosis, and treatment.

Computer-Aided Design and Manufacturing Technology for Identification of Optimal Nuss Procedure and Fabrication of Patient-Specific Nuss Bar for Minimally Invasive Surgery of Pectus Excavatum

The Nuss procedure is one of the most widely used operation techniques for pectus excavatum (PE) patients. It attains the normal shape of the chest wall by lifting the patient’s chest wall with the Nuss bar. However, the Nuss bar is for the most part bent by a hand bender according to the patient’s chest wall, and this procedure causes various problems such as the failure of the operation and a decreased satisfaction of the surgeon and patient about the operation. To solve this problem, we proposed a method for deriving the optimal operation result by designing patient-specific Nuss bars through computer-aided design (CAD) and computer-aided manufacturing (CAM), and by performing auto bending based on the design. In other words, a three-dimensional chest wall model was generated using the computed tomography (CT) image of a pectus excavatum patient, and an operation scenario was selected considering the Nuss bar insertion point and the post-operative chest wall shape. Then, a design drawing of the Nuss bar that could produce the optimal operation result was derived from the operation scenario. Furthermore, after a computerized numerical control (CNC) bending machine for the Nuss bar bending was constructed, the Nuss bar prototype was manufactured based on the derived design drawing of the Nuss bar. The Nuss bar designed and manufactured with the proposed method has been found to improve the Haller index (HI) of the pectus excavatum patient by approximately 37% (3.14 before to 1.98 after operation). Moreover, the machining error in the manufacturing was within ±5% compared to the design drawing. The method proposed and verified in this study is expected to reduce the failure rate of the Nuss procedure and significantly improve the satisfaction of the surgeon and patient about the operation.

A Simplified Method for Three-Dimensional Optical Imaging and Measurement of Patients with Chest Wall Deformities

BACKGROUND

Pectus excavatum and carinatum are two of the most commonly observed chest wall deformities in pediatrics. The standard diagnostic evaluation for these conditions includes either chest radiograph (CXR) or computed tomography (CT). Our research aims to develop a novel and reliable way of quantifying chest wall deformities in the clinic setting without radiation exposure.

METHODS

Using a handheld structured light scanner, we created three-dimensional (3D) models of patients with chest wall deformities through an IRB-approved protocol. Raters from a variety of backgrounds were then asked to take measurements based on the 3D model utilizing commercially available 3D graphical software. The standard deviation of the measurements and intraclass correlation coefficient (ICC) were then calculated to quantify inter-rater reliability.

RESULTS

Sixty patients with pectus excavatum (Haller index range 2.0-6.38) and pectus carinatum were enrolled and imaged in our outpatient clinic using a structured light scanner. Five patients were used to verify interuser reliability. The standard deviation of all the measurements was 2.2 mm. The ICC for absolute agreement was 0.99139, with 1.0 being perfect correlation.

CONCLUSION

Structured light scanners provide an alternative approach to quantifying chest wall deformities in pediatric patients without radiation exposure. Our method is highly reliable, even among users with minimal image processing or 3D modeling experience. Our protocol can potentially be used to track treatment progress in children with chest wall deformities.

Quantification of pectus excavatum: Anatomic indices

Pectus excavatum is the most common chest wall deformity in children. The central portion of the chest is displaced posteriorly relative to the remainder of the anterior chest wall. Quantification of defect severity can be performed with multiple imaging modalities or external thoracic measures, but is most commonly quantified by the Haller Index (HI) or Pectus Correction Index (PCI). These two measures provide a measure of the chest based on cross sectional imaging, most commonly CT scans, allowing for standard comparison and definitions of pectus defects. The purpose of this article is to describe the creation, calculation, and limitations of the methods quantifying pectus defects.

Pectus updates and special considerations in Marfan syndrome

Congenital chest wall or pectus deformities including pectus excavatum (funnel chest) and pectus carinatum (pigeon chest) affect a significant proportion of the general population and up to 70% of patients with Marfan syndrome. Patients often experience significant morbidity and psychological distress, which can worsen with age. Here we discuss new techniques for both operative and non-operative treatment of pectus deformity, the importance of a welltimed intervention and special considerations in patients with Marfan syndrome.

Does an external chest wall measurement correlate with a CT-based measurement in patients with chest wall deformities?

BACKGROUND

Measurements in chest wall deformities are typically conducted using a thorax caliper or a CT scan of the chest wall. This paper focuses on the possible correlation between these two methods to validate the reliability of the thorax caliper, minimize radiation exposure, and limit the usage of expensive imaging techniques.

METHODS

We evaluated 95 consecutive patients (77 pectus excavatum (PE), 17 pectus carinatum (PC), 1 mixed deformity) who received surgical correction of the anterior chest wall. The results of the external chest wall measurements and the CT-based measurements were statistically compared.

RESULTS

A significant correlation between the two measurements was observed in PE and PC at the highest point of the deformation. The strongest correlation was noted in PE. We also noted a correlation between the transverse diameter of the external measurement and the inner thoracic diameter of the CT scan but not for the sagittal diameters in the upper parts of the sternum.

CONCLUSIONS

Thorax caliper measurements are suitable for determining the sagittal thoracic diameter at the maximum level of the deformity and the transverse diameter with an accuracy comparable to that of CT measurements. Since these values key, the thorax caliper is reliable for monitoring and documenting chest wall malformations.

LEVEL OF EVIDENCE

Study of diagnostic test. Testing previously developed diagnostic criteria in a consecutive series of patients and a universally "gold" standard-Level I.

The modified percent depth: Another step toward quantifying severity of pectus excavatum without cross-sectional imaging

INTRODUCTION

Current approaches to quantifying the severity of pectus excavatum require internal measurements based on cross-sectional imaging. This study evaluated the modified percent depth (MPD), a novel index of severity that can be obtained with external measurements, potentially avoiding the need for cross-sectional imaging.

METHODS

Patients undergoing surgical repair of pectus excavatum (pectus group), and those undergoing cross-sectional imaging for unrelated reasons (control group), between 2010 and 2016 were included. The MPD of the deformity was calculated using external (i.e. skin surface to skin surface) measurements from the radiographic images. The same external measurements were taken using chest calipers on a subset of these patients in the outpatient clinic. The optimal threshold for MPD that defined severe pectus deformity was derived from receiver-operator characteristic (ROC) analysis. Sensitivity and specificity of the MPD was compared with that of the Haller Index (HI) and Correction Index (CI).

RESULTS

There were 92 children (49 pectus, 43 controls) included. The median MPD was 20.2% and 4.2% for pectus and control patients, respectively (p<0.0001). An MPD cutoff of 10% optimally discriminated between severe pectus patients and controls by ROC analysis. An MPD of >10% had 98% sensitivity and 98% specificity for severe pectus deformity. Sensitivity and specificity were respectively 93% and 93% for HI >3.25, and 100% and 79% for CI >10.

CONCLUSION

An MPD >10% performs slightly better than the HI and CI in distinguishing patients with severe pectus deformities. This novel measurement approach offers distinct advantages over existing indices, in that it does not require cross-sectional imaging and can be done using chest calipers in the office setting. Further studies with larger sample size are needed to verify reproducibility of the technique.

LEVEL OF EVIDENCE

Level II, Study of Diagnostic Test.

Pectus Excavatum: More Than a Matter of Aesthetics

Pectus excavatum (PE) is the most common congenital chest abnormality, and affects males 5 times more frequently than females. PE results from improper fusion of the ribs with the sternum during embryologic development. The cardinal presenting sign is chest depression. Evaluation includes serial measurement of the chest deformity defect. Additional evaluation of cardiopulmonary function, including arrhythmias and pulmonary function tests, should be done as well. Computed tomography scans are used to determine the Haller index, a measure of deformity severity, with a measurement of greater than 3.2 deemed severe. The main indication of repair is decreased cardiopulmonary capacity, not cosmetic. Surgical repair should be timed such that it occurs after the pediatric growth spurt. Generally, the Nuss procedure, which is minimally invasive, is the first-line surgical repair. Ravitch, or open repair, is used for more complex or asymmetric deformities. [Pediatr Ann. 2016;45(11):e403-e406.].

Assessment of potential confounders when imaging pectus excavatum with chest radiography alone

BACKGROUND

Chest radiography (CXR) has emerged as an attractive alternative imaging option for objective pre-operative assessment of pectus excavatum (PE) with comparable accuracy, reduced cost, and less radiation exposure when compared to computed tomography (CT). This study asked whether image quality, scoliosis, and asymmetry of the PE deformity would decrease the accuracy of CXR as compared to CT.

METHODS

A database of PE patients receiving preoperative CXR and CT was created, and Haller-indices (HI) and correction-indices (CI) were calculated using each imaging modality. Each potential confounding variable were analyzed using Spearman correlations the Fisher r-to-z transformation test.

RESULTS

The database was comprised of 77 patients. Image quality, scoliosis and the 'eccentric type' of asymmetry did not demonstrate any significant worsening of measurement accuracy. However, the correlation coefficients for CIs for those with and without the 'unbalanced type' of asymmetry were 0.593 and 0.890, respectively, with a Fisher r-to-z of 2.16 (p=.031).

CONCLUSIONS

The accuracy of CXR-derived pectus indices remains quite favorable despite the heterogeneity from radiographic quality, scoliosis and chest wall asymmetry. Nonetheless, the unbalanced type of chest wall asymmetry did emerge as a significant confounder. As such, use of CXR alone in cases of gross chest wall asymmetry should be cautioned.

Early and Late Results of the Nuss Procedure in Surgical Treatment of Pectus Excavatum in Different Age Groups

BACKGROUND

The aim of this study was a comparison of early and late results in surgical treatment of funnel chest using the Nuss method in patients in various age groups to find the optimal age to perform the corrective procedure.

METHODS

Six hundred eighty patients operated on from June 2002 to October 2012 were included in the retrospective analysis. Patients were divided into 3 different age groups: group A = 156 patients from 7 to 14 years, group B = 328 patients aged 15 to 20 years, and group C = 196 patients older than 20 years of age. The mean follow-up was 33 months.

RESULTS

Early non-life-threatening complications developed in 238 (35.0%) patients and frequency increased with age (group A, 24.3%; group B, 37.8%; group C, 38.8%; p = 0.0063). Good and very good corrective effects were achieved in 97.7 % of the entire patient population. Recurrence of the deformity was observed more often in younger patients (group A, 3.2 %) than in the other patients (group B, 1.2%; group C, 1.5%), although the difference between the studied groups was not significant (p = 0.3251).

CONCLUSIONS

Good cosmetic results obtained with the use of the Nuss operation were not related to the age of the patients. The high incidence of minor complications in older patients seems to be an acceptable cost of a good cosmetic outcome and stable correction. Surgical morbidity is lowest in younger patients; however, the frequency of the recurrence of deformation is higher than in other groups.

Pectus excavatum severity underestimated due to lack of objective measures in radiological reports

During a routine physical examination, the degree of pectus excavatum (PE) is not always appreciated as the external appearance does not always reflect the severity of the deformity. In the patient in this case report, the severity had been underestimated for 33 years. The physicians, having requested standard two-view chest radiographs, had relied solely on the radiological reports, where the PE had been ambiguously described as 'moderate' or 'substantial'. In patients where PE has been observed, it is essential that an objective numeric measure of severity, using the Haller index, is included in radiological reports.

The case for using the correction index obtained from chest radiography for evaluation of pectus excavatum

BACKGROUND

We previously reported the use of a computed tomography (CT)-based Correction Index (CI) as a more accurate assessment of pectus excavatum (PE) severity than the historically used Haller Index (HI). This study examines the diagnostic capabilities of the CI as assessed by lateral chest radiography (CXR).

METHODS

A database of PE patients receiving preoperative CXR and CT was created. For each patient, a radiologist calculated a CT-based CI, while two pediatric surgeons independently calculated CXR CIs.

RESULTS

The database was composed of 69 patients. Significant correlations were found between CXR CI estimates of the two observers and between the CXR and CT CI for each observer. Per our previous work, CT CIs were used in this study for identifying patients meeting surgical criteria (CT CI≥28%). Observed CXR CIs demonstrated good interrater reliability. The sensitivity (0.83) and specificity (0.77) of CXR in diagnosing severe PE (CT CI≥28%) was high. However, sensitivity (0.89) markedly improved when only considering measured CXR CIs≤26%, and combined specificity rose to 0.86 when only considering measured CXR CIs≥30%.

CONCLUSIONS

We recommend the CI as measured by lateral CXR for the preoperative evaluation of PE, with CT used as a confirmatory test in patients measured to have a CXR CI between 26% and 30%.

Pulmonary function recovery demonstrated by ventilation-perfusion scan after posterior vertebral column resection for severe adolescent idiopathic scoliosis: a case report

STUDY DESIGN

Case report.

OBJECTIVE

To describe a case in which a patient regained pulmonary function, assessed by ventilation-perfusion scans, after undergoing posterior vertebral column resection (VCR) to correct severe adolescent idiopathic scoliosis (AIS) with associated pulmonary dysfunction.

SUMMARY OF BACKGROUND DATA

Pulmonary improvement after corrective surgery for AIS has been reported. Ventilation-perfusion scans are useful for assessing pulmonary function. However, these scans have not been used to examine the recovery of pulmonary function after VCR for severe AIS with pulmonary dysfunction.

METHODS

A patient was described in whom ventilation-perfusion scans were used to examine improvements in impaired air ventilation and blood perfusion after VCR surgery for severe AIS. The relevant literature was reviewed.

RESULTS

An 18-year-old male came to Keio University Hospital with exertional dyspnea associated with severe AIS. Radiographs showed severe scoliosis of 91° at T6-T12, and hypokyphosis of 6° at T5-T12. Computed tomographic scans showed narrowing of the thoracic cage on the convex side of the main thoracic curve, with the vertebral bodies at the apex of the curve obstructing the right main bronchus. Pulmonary function tests revealed a percent vital capacity of 44% and percent forced expiratory volume in 1 second of 76%. A ventilation-perfusion scan showed decreased air ventilation and blood perfusion in the right lung. The patient underwent posterior correction surgery, which used segmental pedicle screws with a VCR at T9. The scoliosis was corrected to 28°, and the kyphosis to 14°. Postoperative computed tomographic scans showed expansion of the right main bronchus. A ventilation-perfusion scan conducted 1 year after surgery showed clear improvement in both ventilation and blood perfusion in the right lung. The patient's forced expiratory volume in 1 second had increased to 91%.

CONCLUSION

This is the first report in which ventilation-perfusion scans were used to examine improvements in impaired air ventilation and blood perfusion after VCR surgery in a patient with severe AIS.

LEVEL OF EVIDENCE

N/A.

Defining the Role of Chest Radiography in Determining Candidacy for Pectus Excavatum Repair

Objective

The Haller index (HI), derived from computed tomography (CT) of the chest, remains the standard for determining pectus excavatum (PE) severity. The ability to accurately determine PE severity from chest radiography (CXR) may provide substantial benefits. This study proposes to establish data-driven criteria for the use of CXR as a diagnostic modality in the preoperative evaluation of patients with PE.

Methods

A database of 77 patients with PE receiving preoperative CXR and CT was created. Haller indices were obtained from CT scans. Two cardiothoracic surgeons, blinded to the CT HI scores, independently calculated CXR HIs. Interrater reliability, correlations, sensitivity, specificity, and accuracy were calculated.

Results

A significant correlation was found between CXR HI estimates of the two observers, r = 0.84. Computed tomography HIs were used as the standard for identifying patients meeting surgical criteria (CT HI ≥3.2). From this, sensitivities, specificities, and accuracies were calculated for the corresponding CXR HIs determined by each observer. Observer CXR HI estimates had a sensitivity of 0.94 and 0.92, specificity of 0.77 and 0.42, and accuracy of 0.88 and 0.75.

Conclusions

We found a strong correlation between HIs calculated with each modality. In addition, CXR HIs demonstrated good interrater reliability. Although the sensitivity of CXR in diagnosing severe PE (CT HI ≥3.2) was high, specificity was less convincing. However, when using a cutoff of CXR HIs of 3.75 or greater, combined specificity was quite high (0.96). We recommend replacing CT with CXR in the pre-operative evaluation for PE. Computed tomography should be used as a confirmatory test for CXR HIs between 3.2 and 3.75.

Usefulness of chest images for the assessment of pectus excavatum before and after a Nuss repair in adults

OBJECTIVES

The aim of this study was to evaluate whether chest radiographs could offer useful information for the assessment of pectus excavatum (PE) before and after Nuss repair in adults.

METHODS

A total of 154 adults, with a mean age of 24.0 ± 5.0 years (range, 18-44 years), who underwent a Nuss repair of PE, with a mean follow-up of 42 months (range, 14-71 months), were included in this retrospective study. Sixty-two of these patients were also evaluated after the pectus bar removal, with a mean follow-up of 13 months (range, 6-44 months). The preoperative and postoperative imaging modalities were compared.

RESULTS

The preoperative mean Haller indices measured on computed tomography (CT) and chest radiographs were 4.61 ± 1.58 (range, 2.6-11.9) and 3.82 ± 1.17 (range, 2.0-10.2), respectively. The Pearson correlation coefficient between the two parameters was 0.757. The postoperative mean Haller index measured on chest radiographs was 2.86 ± 0.56 (range, 1.7-5.4) and showed statistically significant improvement compared with the preoperative index (P < 0.001). The mean sternovertebral (SV) distances detected on preoperative and postoperative (>6 months after surgery) lateral chest radiographs were 7.67 ± 1.89 cm (range, 2.5-12.9 cm) and 9.89 ± 1.80 cm (range, 4.6-15.0 cm), respectively, showing statistically significant improvement (P < 0.001). The mean sternovertebral (SV) distance in patients after the bar removal detected on lateral chest radiographs was 9.25 ± 2.14 cm, also showing statistically significant improvement compared with the preoperative value (P < 0.001).

CONCLUSIONS

Haller indices measured using chest radiographs and CT showed a strong correlation. Therefore, chest radiographs can be used as an alternative tool for the preoperative evaluation of PE. The Nuss operation significantly improved SV distances detected on lateral chest radiographs. Lateral chest radiographs can be used as a simple modality for the objective quantitative assessment of the anatomic results and follow-up of the Nuss operation in adults.

Chest fast MRI: an imaging alternative on pre-operative evaluation of Pectus Excavatum

BACKGROUND

Standard imaging methods in evaluating chest wall deformities, such as Pectus Excavatum (PE) in paediatric and adolescent patients, include baseline 2-view chest radiography and chest CT scan. Only few studies to date investigated the value of fast MRIin the pre operative assessment of patient affected by PE.

OBJECTIVE

To evaluate the efficacy of chest fast MRI in pre-operative management of patient affected by PE. To obtain the Haller Index (HI) and Asymmetry Index (AI) from chest fast MRI protecting patients from radiation exposure.

MATERIALS AND METHODS

We analyzed the data of 42 consecutive patients with severe PE who underwent minimally invasive repair between March 2007 and March 2010. All 42 patients received chest fast MRI, but only the first 5 in view of the results, were studied also with chest ultrafast CT scan. In both examinations, data at the deepest point of the depression were collected.

RESULTS

Severity indices of the deformity using HI and AI, collected from CT scan and fast MRI in the first 5 patients, were comparable. In the remaining 37 fast chest MRI offered good images of the chest wall deformities with no radiation exposure, detailing anatomical information such as displacement and rotation of the heart or great vessels anomalies.

CONCLUSION

This study suggests the use of chest MRI in pre operative workup for patients with PE to obtain severity indices (Haller Index and Asymmetry Index avoiding radiation exposure to paediatric patients.

MRI for the evaluation of pectus excavatum

Pectus excavatum, the most common congenital deformity of the anterior chest wall, is both a cosmetic and functional abnormality. The degree of abnormal chest wall deformity determines its functional effect, particularly its cardiac and pulmonary impact. Although CT scanning is the most widely used cross-sectional imaging technique used to measure the Haller index, the radiation exposure is reason to seek other alternatives. At our institution, we have introduced a rapid MRI technique for this purpose, which utilizes a single-axial 2-D FIESTA acquisition.