Radiological follow-up of cemento-osseous dysplasia on cone-beam computed tomography.

This study investigated the natural course of cemento-osseous dysplasia (COD) on cone-beam computed tomography (CBCT). Retrospectively, 104 CBCT scans from 36 patients (mean age, 44.5 years; 33 female and three male) with mandibular COD (10 florid, seven focal, 19 periapical) were included, based upon clinico-radiological features, without complications such as infection and related surgery. Changes in maximum diameter and morphology (lytic, mixed lytic-sclerotic, sclerotic) were evaluated in 83 lesions, with a mean follow-up of 28.3 months. The occurrence of a diameter increase was assessed by time-to-event analysis; interreader agreement for diameter and morphological evaluation by intraclass correlation coefficient and weighted κ statistics, respectively. Fifteen of 83 (18.1%) lesions (eight florid, one focal, six periapical) in 10 patients increased in diameter; 12 of 83 (14.5%) lesions (five florid, seven periapical) in 11 patients changed morphologically. The median period until a diameter increase was longest (120 months) for periapical COD, and shortest (66 months) for florid COD (p = 0.023). There was high reader agreement (ICC = 0.891; weighted κ = 0.901). In conclusion, CBCT is an effective tool with which to follow-up COD. If any, the natural progress in uncomplicated COD is prolonged, which underlines its non-surgical character and aids in its long-term management.

Real-world Data of Palliative First-line Checkpoint Inhibitor Therapy for Head and Neck Cancer.

BACKGROUND/AIM: Pembrolizumab alone or combined with chemotherapy is now approved in PD-L1-positive patients with recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). Since real-world data are pending, our goal was to evaluate the efficacy and safety of immune checkpoint inhibitor (CPI) therapy in an unselected cohort of patients with SCCHN. PATIENTS AND METHODS: We analyzed 78 patients with recurrent or metastatic SCCHN from three Austrian cancer centers that received CPI therapy alone or with chemotherapy as palliative first-line systemic treatment for this retrospective study. Patient characteristics, details on treatment, and survival were analyzed by a chart-based review. RESULTS: Of the 78 patients analyzed, 55 patients were treated with CPI alone (45 with Pembrolizumab, 10 with Nivolumab) and 23 patients received chemotherapy with a platinum and 5-FU in addition to CPI. With a median follow-up of twelve months, the median PFS of all patients was 4 months [95% confidence interval (CI)=2.2-5.8] and the median OS was 11 months (95% CI=7.1-14.9). The overall response and disease control rates were 20.5% and 46.1%, respectively. There was no statistically significant difference in clinical outcome between patient groups with a different combined positive score (CPS). The rate of reported immune related adverse events was comparable to existing data. CONCLUSION: Our findings confirm the results of the KEYNOTE-048 trial that CPI therapy alone or together with chemotherapy is an effective treatment for patients with recurrent or metastatic CPS-positive SCCHN.

A homozygous AP3D1 missense variant in patients with sensorineural hearing loss as the leading manifestation.

Loss-of-function variants in AP3D1 have been linked to Hermansky-Pudlak syndrome (HPS) 10, a severe multisystem disorder characterized by oculocutaneous albinism, immunodeficiency, neurodevelopmental delay, hearing loss (HL), and neurological abnormalities, fatal in early childhood. Here, we report a consanguineous family who presented with presumably isolated autosomal recessive (AR) HL. Whole-exome sequencing was performed on all core family members, and selected patients were screened using array-based copy-number analysis and karyotyping. Candidate variants were validated by Sanger sequencing and assessed in silico. A homozygous, likely pathogenic p.V711I missense variant in AP3D1 segregated with the HL. The family was characterized by thorough medical and laboratory examination. The HL was consistent across patients and accompanied by neurological manifestations in two brothers. The sole female patient was diagnosed with premature ovarian failure. Further findings, including mild neutropenia and reduced NK-cell cytotoxicity in some as well as brain alterations in all homozygous patients, were reminiscent of HPS10, though milder and lacking the characteristic albinism. Previously unrecognized, milder, isolated HL was identified in all heterozygous carriers. A protein model indicates that the variant interferes with protein-protein interactions. These results suggest that a missense variant alters inner-ear-specific functions leading to HL with mild HPS10-like symptoms of variable penetrance. Milder HL in heterozygous carriers may point towards semi-dominant inheritance of this trait. Since all previously reported HPS10 cases were pediatric, it is unknown whether the observed primary ovarian insufficiency recapitulates the subfertility in Ap3d1-deficient mice.

Chest computed tomography findings of adult patients with antimelanoma differentiation-associated protein 5 antibody-positive interstitial lung disease.

OBJECTIVES: Interstitial lung disease (ILD) associated with the antimelanoma differentiation-associated protein 5 (anti-MDA5) antibody is a rapidly progressive disease that requires timely, aggressive treatment. However, prompt diagnosis is difficult due to the longer time required for antibody detection. This study described the computed tomography (CT) findings of anti-MDA5 antibody-positive ILD (anti-MDA5-ILD). METHODS: CT findings of 20 patients (7 men, 13 women; mean age, 53.6 ± 13.5 years) with anti-MDA5-ILD were retrospectively reviewed. All patients had clinical diagnoses of dermatomyositis, and 14 patients presented with amyopathic findings. RESULTS: Bilateral ground-glass attenuation, air-space consolidation, and reticular shadows were observed in 20 (100%), 15 (75%), and 3 (15%) patients, respectively. The spread of air-space consolidation was 6.0 ± 5.6% (mean ± standard deviation). Univariate analysis revealed that high Krebs von den Lungen-6, high spread of consolidation, low partial pressure of oxygen, and low forced vital capacity were significant predictors for poor survival. The final radiological diagnoses were nonspecific interstitial pneumonia and organising pneumonia (OP) in 2 (10%) and 16 (80%) patients, respectively. Further, 30% of OP patients showed fibrosis. CONCLUSION: The characteristic CT findings of patients with anti-MDA5-ILD were ground-glass attenuation, air-space consolidation, and less reticulation. These CT findings were compatible with those of OP.

Vertebral Bone Marrow and Endplate Assessment on MR Imaging for the Differentiation of Modic Type 1 Endplate Changes and Infectious Spondylodiscitis.

On magnetic resonance (MR) imaging, Modic type 1 (MT1) endplate changes and infectious spondylodiscitis share similar findings. Therefore, this study investigated vertebral bone marrow and endplate changes to enable their differentiation. The lumbar spine MR examinations of 91 adult patients were retrospectively included: 39 with MT1; 19 with early spondylodiscitis without abscess; and 33 with advanced spondylodiscitis with abscess. The assessment included percentage of bone marrow edema on sagittal short tau inversion recovery images, and the signal ratio of edema to unaffected bone and endplate contour (normal; irregular, yet intact; blurred; destructive) on sagittal unenhanced T1-weighted images. Differences were tested for statistical significance by Chi-square test and mixed model analysis of variance. The MR diagnostic accuracy in differentiating MT1 and spondylodiscitis was assessed by cross-tabulation and receiver-operating characteristic analysis. The endplate contours, edema extents, and T1-signal ratios of MT1 (extent, 31.96%; ratio, 0.83) were significantly different (p < 0.001) from early spondylodiscitis (56.42%; 0.60), and advanced spondylodiscitis (91.84%; 0.61). The highest diagnostic accuracy (sensitivity, 94.87%; specificity, 94.23%; accuracy, 94.51%) in identifying MT1 was provided by an irregular, yet intact endplate contour. This may be a useful MR feature for the differentiation between MT1 and spondylodiscitis, particularly in its early stage.

Lumbar Intervertebral Disc Degeneration as a Common Incidental Finding in Young Pregnant Women as Observed on Prenatal Magnetic Resonance Imaging.

Background: Obstetric imaging, subserving fetal evaluation, may yield incidental maternal findings. Based on prenatal magnetic resonance (MR) imaging, this study aims to investigate incidental intervertebral disc degeneration and displacement in young, pregnant women. Methods: This retrospective study included the sagittal 1.5 Tesla, T2-weighted lumbar spine images of 943 pregnant Central Europeans (age range, 18-47 years), who initially had undergone MR imaging because of sonographically suspected fetal abnormalities. Qualitatively, 4715 lumbar intervertebral discs were evaluated for degeneration using a modified Pfirrmann MR classification (nondegenerated, low-grade, moderate, and high-grade degeneration), as well as for displacement. In addition to descriptive statistics, an ordinal regression analysis was performed to analyze the relationship between degeneration and the women's age, and body weight. Results: With regard to the highest degree of degeneration in each woman, 578 (61.3%) showed low-grade, 211 (22.4%) moderate, and 154 (16.3%) high-grade degeneration, and no woman had entirely nondegenerated discs. For the span from 18 to 47 years of age, moderate and high-grade degeneration increased from 6.7% to 36.7% and from 13.3% to 22.4%, respectively. Of 943 women, 57 (6%) had disc displacements, of which 97% were in conjunction with high-grade degeneration. There was a statistically significant relationship (p < 0.001) between degeneration and age, and between degeneration and body weight. Conclusions: In young pregnant women, lumbar intervertebral disc degeneration is a ubiquitous, incidental finding, increasing from the late second decade of life onward, which may be part of physiological aging, as opposed to a small percentage of incidental disc displacements.

Midfacial Advancement Line-A Comparative Evaluation of a New Measurement Method in Orthognathic Surgery.

PURPOSE: In planning intraoral quadrangular Le Fort II osteotomy (IQLFIIO), simulation of hard and soft tissue changes will be important at the infraorbital, Le Fort I, and incisor level. The aim of our study was to evaluate a new method for visualization and quantification. MATERIALS AND METHODS: Three different methods of quantification were compared: the point-to-point (PTP) measurement, which has been viewed as the reference standard; part comparison analysis (PCA); and a new method, the midfacial advancement line (MFAL) measurement. We performed a measurement comparison study using the Bland-Altman method to measure agreement and enrolled patients with midfacial deficiency and Class III malocclusion who had undergone IQLFIIO. The primary predictor variable was the method of measurement. The primary outcome variable was the amount of midfacial advancement. We also investigated the time required, visualization quality, and interobserver agreement. RESULTS: The sample included 12 subjects with a mean age of 21.6 years; 7 patients were male. The PTP and MFAL showed no significant observer dependence. The advancement measured with PTP and MFAL showed no significant differences. However, the advancement measured using MFAL and PCA showed a significant difference. The highest rating of visualization was found for MFAL. The time requirements were similar for all 3 methods. CONCLUSIONS: Our results have shown that the MFAL is a suitable method for visualization and quantification of soft and hard tissue changes at all 3 face levels in 1 image. It could be a valuable tool for virtual planning of midfacial advancement surgery.

When an incidental MRI finding becomes a clinical issue : Posterior lumbar subcutaneous edema in degenerative, inflammatory, and infectious conditions of the lumbar spine.

BACKGROUND: On magnetic resonance imaging (MRI), posterior lumbar subcutaneous edema (PLSE) is a frequent incidental, yet unclear finding within the deep subcutaneous perifascial tissue. This study aimed to investigate PLSE in various pathological lumbar conditions. METHODS: This retrospective study included the MR images of the lumbar spine of 279 patients (age range 18-82 years) without cardiovascular, renal or hepatic diseases, 79 of whom had low-grade disc degeneration, 101 combined endplate and facet joint degeneration, 53 axial spondyloarthritis and 46 infectious spondylodiscitis. There were 232 patients with a body mass index (BMI) <30, and 47 with a BMI ≥30 (obese). For each group, the relationship between PLSE and BMI was analyzed using multiple logistic regression, and between PLSE extension and BMI using ordinal regression. RESULTS: A PLSE was found in 11/79 (13.9%) patients with disc degeneration, 37/101 (36.6%) with endplate and facet joint degeneration, 7/53 (13.2%) with spondyloarthritis, and 28/46 (60.9%) with spondylodiscitis. For each group, a statistically significant relationship was demonstrated between PLSE and BMI (P = 0.000-P = 0.031), except for spondylodiscitis (P = 0.054), as well as between PLSE extension and BMI (P = 0.000-P = 0.049). A PLSE was found in 21.1% of nonobese and 72.3% of obese patients (P = 0.000). CONCLUSION: The presence of PLSE seems to be associated with various lumbar conditions, particularly in obese patients. Its perifascial location may suggest a potential fascial origin; however, PLSE should not to be confused with posttraumatic, postsurgical or infectious edema or edema associated with internal diseases.

Computed tomography accelerates staging in patients with Merkel cell carcinoma.

PURPOSE: No imaging algorithms for diagnostic imaging in patients suffering from Merkel cell carcinoma (MCC) have been established so far and thus staging work-up is challenging. Long presentation-to-treatment intervals determine further treatment course and, consequently, have an impact on clinical outcome in patients with MCC. METHODS: In this retrospective study, diagnostic imaging of 37 MCC patients was analyzed. CT, ultrasound, and PET/PET-CT imaging for primary staging work-up with time frames from patients´ initial presentation and imaging until completion of tumor staging were analyzed. RESULTS: Tumor staging could be completed earlier when (1) less examinations (35 vs. 42 days) were carried out or (2) computed tomography was used as the initial imaging modality (28 vs. 35 days). Furthermore, CT imaging, when used as the initial imaging study, was linked to less follow-up imaging (3 vs. 6). CONCLUSION: Computed tomography as the first-staging imaging technique in MCC patients leads to less follow-up studies and fastest completion of tumor staging.

Prognostic survival value of retropharyngeal lymph node involvement in sinonasal tumors: A retrospective, descriptive, and exploratory study.

BACKGROUND: Sinonasal carcinomas are rare. The purpose of this study was for us to present our assessment of the effects of retropharyngeal lymph node involvement at diagnosis on patient outcomes. METHODS: Retropharyngeal lymph node involvement in 36 patients with sinonasal carcinoma was determined by radiology at initial presentation. Clinical outcome, in particular, overall survival (OS) and locoregional control, was assessed by Kaplan-Meier analysis and log-rank testing. RESULTS: Retropharyngeal lymph node involvement was associated with statistically significant decreased OS (P = .0066) in the patient collective. In the squamous cell carcinoma (SCC) subgroup (n = 23), decreased OS (P = .0046) and worse locoregional control (P = .0065) were observed. In these patients, decreased OS (P = .0423) and worse locoregional control (P = .0315) were also seen in the advanced tumor subgroup. CONCLUSION: Retropharyngeal lymph node involvement at diagnosis is a significant prognostic factor for decreased OS and locoregional control in sinonasal carcinoma.

Morphometric analysis of sinus depth in the posterior maxilla and proposal of a novel classification.

The aim of this study was to analyse the posterior maxillary sinus based on its extension into the alveolar process and to provide a simple clinical classification. A retrospective cohort study was conducted in CT scans of 200 dentate and 200 edentulous patients (100 women and 100 men, respectively). After manual placement of 12 reference points morphometric analysis was performed and sinus depth, residual alveolar ridge height (RH) and the sinus opening angle were calculated. Sinuses were classified according to the quartiles of sinus depth: class I (above the hard palate), class II (0-6 mm below the hard palate) and class III (>6 mm below the hard palate). Sinus depth was found to be a reliable anatomical landmark and did not vary significantly between gender (p = 0.8940) or dentition groups (p = 0.9723). Alveolar height varied significantly between sinus classes (p < 2 × 10-16) and dentition groups (p < 2 × 10-16) but not between genders (p = 0.5178). The sinus opening angle was significantly different between sinus classes (p < 2.2 × 10-16) but not between gender or dentition groups. We propose a novel classification built upon the quartiles of sinus depth, dividing the sinuses into three classes. Our classification is the first one that represents the anatomy of the patient independent of gender and dentition.

Clinical Management of Impacted and Transmigrated Lower Canines.

PURPOSE: Impacted, in particular transmigrated, lower canines are rare. If they transmigrate, then the most common treatment is extraction. Alternatively, the native tooth can be preserved; however, management is complex. This report describes a decision-making flowchart (DMFC) with surgical strategies for the management of impacted lower canines. MATERIALS AND METHODS: Fifty-six patients had impacted lower canines, of which 16 were transmigrated. A preliminary version of the DMFC was used for the development of treatment plans to decide which strategy to apply to these complex cases. After removal of associated pathologies (for experimental tooth-preserving therapies), miniscrews were used as transient skeletal anchorage devices (TADs). The TADs allowed a closed surgical approach for impacted and transmigrated lower canine eruption. For autotransplantation, a dummy tooth was used for socket preparation to minimize the period of no blood supply to the graft. RESULTS: After surgical exposure and TAD insertion, orthodontic treatment was performed in 4 patients. One patient was selected for successful autotransplantation. Nine patients had the transmigrated canines surgically removed. The remaining patients opted for "leave and observe." Based on the satisfactory long-term results with orthodontic treatment and autotransplantation and on published reports, the resulting DMFC presents key aspects of the treatment plan, namely 1) associated pathology, 2) patient age, 3) compliance, and 4) root tip position. CONCLUSIONS: TAD-assisted orthodontic treatment and autotransplantation of impacted lower canines are tooth-preserving alternatives to extraction. The developed DMFC assists the complex treatment planning of impacted and transmigrated lower canines.

Changes in Cartilage and Tendon Composition of Patients With Type I Diabetes Mellitus: Identification by Quantitative Sodium Magnetic Resonance Imaging at 7 T.

OBJECTIVE: The aim of this study was to investigate possible biochemical alterations in tendons and cartilage caused by type 1 diabetes mellitus (DM1), using quantitative in vivo 7 T sodium magnetic resonance (MR) imaging. MATERIALS AND METHODS: The institutional review board approved this prospective study, and written informed consent was obtained. Eight DM1 patients with no history of knee trauma and 9 healthy age- and weight-matched volunteers were examined at 7 T using dedicated knee coils.All participants underwent morphological and sodium MR imaging. Region-of-interest analysis was performed manually for the non-weight-bearing area of the femoral condyle cartilage and for the patella tendon. Two readers read the image data sets independently, twice, for intrareader and interreader agreement. Normalized mean sodium signal intensity (NMSI) values were compared between patients and volunteers for each reader using analysis of variance. RESULTS: On morphological images, cartilage in the non-weight-bearing area and the patellar tendon was intact in all patients. On sodium MR imaging, bivariate analysis of variance showed significantly lower mean NMSI values in the cartilage (P = 0.008) and significantly higher values in the tendons (P = 0.025) of patients compared with those of volunteers. CONCLUSION: Our study showed significantly different NMSI values between DM1 patients and matched volunteers. Differences observed in the cartilage and tendon might be associated with a DM1-related alteration of biochemical composition that occurs before it can be visualized on morphological MR sequences.

Normal spectrum of pulmonary parametric response map to differentiate lung collapsibility: distribution of densitometric classifications in healthy adult volunteers.

OBJECTIVES: Pulmonary parametric response map (PRM) was proposed for quantitative densitometric phenotypization of chronic obstructive pulmonary disease. However, little is known about this technique in healthy subjects. The purpose of this study was to describe the normal spectrum of densitometric classification of pulmonary PRM in a group of healthy adults. METHODS: 15 healthy volunteers underwent spirometrically monitored chest CT at total lung capacity (TLC) and functional residual capacity (FRC). The paired CT scans were analyzed by PRM for voxel-by-voxel characterization of lung parenchyma according to 4 densitometric classifications: normal lung (TLC ≥ -950 HU, FRC ≥ -856 HU); expiratory low attenuation area (LAA) (TLC ≥ -950 HU, FRC < -856 HU); dual LAA (TLC<-950 HU, FRC < -856 HU); uncharacterized (TLC < -950 HU, FRC ≥ -856 HU). RESULTS: PRM spectrum was 78 % ± 10 % normal lung, 20 % ± 8 % expiratory LAA, and 1 % ± 1 % dual LAA. PRM was similar between genders, there was moderate correlation between dual LAA and spirometrically assessed TLC (R = 0.531; p = 0.042), and between expiratory LAA and VolExp/Insp ratio (R = -0.572; p = 0.026). CONCLUSIONS: PRM reflects the predominance of normal lung parenchyma in a group of healthy volunteers. However, PRM also confirms the presence of physiological expiratory LAA seemingly related to air trapping and a minimal amount of dual LAA likely reflecting emphysema. KEY POINTS: • Co-registration of inspiratory and expiratory computed tomography allows dual-phase densitometry. • Dual-phase co-registered densitometry reflects heterogeneous regional changes in lung function. • Quantification of lung in healthy subjects is needed to set reference values. • Expiratory low attenuation areas <30 % could be considered within normal range.

MR neurography of ulnar nerve entrapment at the cubital tunnel: a diffusion tensor imaging study.

OBJECTIVES: MR neurography, diffusion tensor imaging (DTI) and tractography at 3 Tesla were evaluated for the assessment of patients with ulnar neuropathy at the elbow (UNE). METHODS: Axial T2-weighted and single-shot DTI sequences (16 gradient encoding directions) were acquired, covering the cubital tunnel of 46 patients with clinically and electrodiagnostically confirmed UNE and 20 healthy controls. Cross-sectional area (CSA) was measured at the retrocondylar sulcus and FA and ADC values on each section along the ulnar nerve. Three-dimensional nerve tractography and T2-weighted neurography results were independently assessed by two raters. RESULTS: Patients showed a significant reduction of ulnar nerve FA values at the retrocondylar sulcus (p = 0.002) and the deep flexor fascia (p = 0.005). At tractography, a complete or partial discontinuity of the ulnar nerve was found in 26/40 (65%) of patients. Assessment of T2 neurography was most sensitive in detecting UNE (sensitivity, 91%; specificity, 79%), followed by tractography (88%/69%). CSA and FA measurements were less effective in detecting UNE. CONCLUSION: T2-weighted neurography remains the most sensitive MR technique in the imaging evaluation of clinically manifest UNE. DTI-based neurography at 3 Tesla supports the MR imaging assessment of UNE patients by adding quantitative and 3D imaging data. KEY POINTS: • DTI and tractography support conventional MR neurography in the detection of UNE • Regionally reduced FA values and discontinuous tractography patterns indicate UNE • T2-weighted MR neurography remains the imaging gold standard in cases of UNE • DTI-based ulnar nerve tractography offers additional topographic information in 3D.

Use of diagnostic dynamic contrast-enhanced (DCE)-MRI for targeting of soft tissue tumour biopsies at 3T: preliminary results.

OBJECTIVES: To test the feasibility and accuracy of MR-guided soft tissue tumour biopsy at 3T, using the dynamic contrast-enhanced (DCE) information from staging MRI for intralesional targeting. METHODS: After obtaining written informed consent for this institutional review board-approved study, 53 patients with suspected soft tissue tumours prospectively underwent preoperative staging MRI at 3T, including DCE, and subsequent MR-guided core needle biopsy. In 44/53 cases, DCE was heterogeneous and was used for intralesional biopsy targeting. Surgical, whole-specimen histology was used as the gold standard in 43/44 patients and revealed 42 soft tissue tumours (24 men; 18 women; mean age, 52 years; range, 19 - 84). RESULTS: Final surgical histology revealed eight benign lesions, six tumours of intermediate dignity, and 28 malignancies. All malignancies had shown heterogeneous DCE. The diagnostic yield of the biopsies was 100% (42/42). Histological accuracy rates of biopsy were 100% in predicting the dignity (42/42; 95% CI [0.916 - 1.000]), 95.2% for the tissue-specific entity (40/42; 95% CI [0.847 - 0.987]), and 90.5% for the tumour grade (38/42; 95% CI [0.779 - 0.962]). CONCLUSIONS: Our preliminary study indicates that biopsy of soft tissue tumours can be performed accurately and safely with DCE targeted MR-guidance at 3T, using a combined staging/biopsy MRI protocol. KEY POINTS: • MR-guided soft tissue tumour biopsy using DCE for intralesional targeting is feasible. • Targeting by staging-MRI allows reliable planning of the biopsy approach. • The method seems accurate and safe as a combined staging/biopsy procedure in outpatients. • DCE-targeted biopsy seems useful in challenging large and heterogeneous tumours.

Comparison of four software packages for CT lung volumetry in healthy individuals.

OBJECTIVES: To compare CT lung volumetry (CTLV) measurements provided by different software packages, and to provide normative data for lung densitometric measurements in healthy individuals. METHODS: This retrospective study included 51 chest CTs of 17 volunteers (eight men and nine women; mean age, 30 ± 6 years), who underwent spirometrically monitored CT at total lung capacity (TLC), functional residual capacity (FRC), and mean inspiratory capacity (MIC). Volumetric differences assessed by four commercial software packages were compared with analysis of variance (ANOVA) for repeated measurements and benchmarked against the threshold for acceptable variability between spirometric measurements. Mean lung density (MLD) and parenchymal heterogeneity (MLD-SD) were also compared with ANOVA. RESULTS: Volumetric differences ranged from 12 to 213 ml (0.20 % to 6.45 %). Although 16/18 comparisons (among four software packages at TLC, MIC, and FRC) were statistically significant (P < 0.001 to P = 0.004), only 3/18 comparisons, one at MIC and two at FRC, exceeded the spirometry variability threshold. MLD and MLD-SD significantly increased with decreasing volumes, and were significantly larger in lower compared to upper lobes (P < 0.001). CONCLUSIONS: Lung volumetric differences provided by different software packages are small. These differences should not be interpreted based on statistical significance alone, but together with absolute volumetric differences. KEY POINTS: • Volumetric differences, assessed by different CTLV software, are small but statistically significant. • Volumetric differences are smaller at TLC than at MIC and FRC. • Volumetric differences rarely exceed spirometric repeatability thresholds at MIC and FRC. • Differences between CTLV measurements should be interpreted based on comparison of absolute differences. • MLD increases with decreasing volumes, and is larger in lower compared to upper lobes.

Normal mandibular growth and diagnosis of micrognathia at prenatal MRI.

OBJECTIVE: The aim of this article is to present reference data for fetal mandibular growth on magnetic resonance imaging, enabling the diagnosis of micrognathia. METHODS: Retrospectively, on 355 magnetic resonance scans of apparently facially normal fetuses [gestational age (GA), 20-36 weeks], mandibular anterior-posterior diameter (APD = mandibular size), inferior facial angle (IFA = mandibular position), and jaw index (APD normalized to biparietal diameter) were correlated with GA by Pearson correlation. APD-age relationship was modeled. A receding chin was subjectively determined. Ten fetuses with mandibular anomalies were compared with normal fetuses. RESULTS: For GA, APD showed high correlation (r = 0.850; P < 0.001), IFA (r = 0.086; P = 0.119) no correlation, and jaw index (r = -0.139; P = 0.018) weak correlation. APD-age relationship was expressed by the following: APD = 0.281 + 0.989 * GA (r(2) = 0.723). A receding chin was identified in 7/10 abnormal fetuses. APD, IFA, and jaw index of abnormal and normal fetuses were significantly different (P < 0.001). In 10/10 abnormal fetuses, IFA was <50.0°; in 7/10, jaw index was less than the fifth percentile (micrognathia); in 3/10, jaw index was at low normal range (retrognathia). CONCLUSIONS: Subjective identification of micrognathia may be limited. Reference data provide quantitative evaluation of mandibular size and position. An IFA <50° reflects micrognathia or retrognathia; a jaw index less than the fifth percentile suggests micrognathia.