"Black Bone" MRI: a novel imaging technique for 3D printing.

OBJECTIVES: Three-dimensionally printed anatomical models are rapidly becoming an integral part of pre-operative planning of complex surgical cases. We have previously reported the "Black Bone" MRI technique as a non-ionizing alternative to CT. Segmentation of bone becomes possible by minimizing soft tissue contrast to enhance the bone-soft tissue boundary. The objectives of this study were to ascertain the potential of utilizing this technique to produce three-dimensional (3D) printed models. METHODS: "Black Bone" MRI acquired from adult volunteers and infants with craniosynostosis were 3D rendered and 3D printed. A custom phantom provided a surrogate marker of accuracy permitting comparison between direct measurements and 3D printed models created by segmenting both CT and "Black Bone" MRI data sets using two different software packages. RESULTS: "Black Bone" MRI was successfully utilized to produce 3D models of the craniofacial skeleton in both adults and an infant. Measurements of the cube phantom and 3D printed models demonstrated submillimetre discrepancy. CONCLUSIONS: In this novel preliminary study exploring the potential of 3D printing from "Black Bone" MRI data, the feasibility of producing anatomical 3D models has been demonstrated, thus offering a potential non-ionizing alterative to CT for the craniofacial skeleton.

Three-Dimensional Reconstruction of the Craniofacial Skeleton With Gradient Echo Magnetic Resonance Imaging ("Black Bone"): What Is Currently Possible?

Three-dimensional (3D) reconstructed computed tomography (CT) imaging has become an integral component of craniomaxillofacial patient care. However, with increasing concern regarding the use of ionizing radiation, particularly in children with benign conditions who require repeated examinations, dose reduction and nonionizing alternatives are actively being sought. The "Black Bone" magnetic resonance imaging (MRI) technique provides uniform contrast of the soft tissues to enhance the definition of cortical bone. The aim of this study was to develop methods of 3D rendering of the craniofacial skeleton and to ascertain their accuracy. "Black Bone" MRI datasets acquired from phantoms, adult volunteers and patients were segmented and surface and/or volume rendered using 4 commercially available or open source software packages. Accuracy was explored using a custom phantom (permitting direct measurement), CT and MRI. "Black Bone" MRI datasets were successfully used to create 3D rendered images of the craniofacial skeleton in all 4 software packages. Comparable accuracy was achieved between CT and MRI 3D rendered images of the phantom. The "Black Bone" MRI technique provides a viable 3D alternative to CT examination when imaging the craniofacial skeleton.

"Black Bone" MRI: a potential alternative to CT with three-dimensional reconstruction of the craniofacial skeleton in the diagnosis of craniosynostosis.

OBJECTIVES: To determine the potential of novel gradient echo parameters, "Black Bone" MRI as an alternative to CT in the identification of normal and prematurely fused cranial sutures both in 2D and 3D imaging. METHODS: Thirteen children with a clinical diagnosis of craniosynostosis underwent "Black Bone" MRI in addition to routine cranial CT. "Black Bone" datasets were compared to CT and clinical findings. "Black Bone" imaging was subsequently used to develop 3D reformats of the craniofacial skeleton to enhance further visualisation of the cranial sutures. RESULTS: Patent cranial sutures were consistently identified on "Black Bone" MRI as areas of increased signal intensity. In children with craniosynostosis the affected suture was absent, whilst the remaining patent sutures could be visualised, consistent with CT and clinical findings. Segmentation of the "Black Bone" MRI datasets was successful with both threshold and volume rendering techniques. The cranial sutures, where patent, could be visualised throughout their path. CONCLUSIONS: Patent cranial sutures appear as areas of increased signal intensity on "Black Bone" MRI distinct from the cranial bone, demonstrating considerable clinical potential as a non-ionising alternative to CT in the diagnosis of craniosynostosis. KEY POINTS: • Patent cranial sutures appear hyperintense on "Black Bone" MRI • Prematurely fused cranial sutures are distinct from patent sutures • Minimal soft tissue contrast permits 3D-rendered imaging of the craniofacial skeleton.

MRI pre-treatment tumour volume in maxillary complex squamous cell carcinoma treated with surgical resection.

UNLABELLED: Tumour volume (Tv) measurements obtained from pre-treatment CT and MRI have increasingly shown to be more reliable predictors of outcome than TNM stage. The aim of this study was to determine the correlation of MRI calculated maxillary complex tumour volume with patient outcome. METHODS: The medical records of 39 patients with squamous cell carcinoma involving the maxillary sinus, maxilla, hard palate and maxillary alveolus were reviewed and tumour volume measurements completed on pre-treatment MRI. RESULTS: The mean tumour volume was 12.79 ± 24.31 cm(3). Independent samples t test was significant for increasing overall all-cause survival and decreasing tumour volume (1 year: p = 0.003; 5-year: p = 0.031). Cox regression was significant for stratified tumour volume, nodal involvement and peri-neural invasion for predicting disease-free survival. CONCLUSIONS: MRI measured tumour volume assessment appears to be a reliable predictor of survival in patients with maxillary complex SCC treated by surgical resection.

Normal values of regional and global myocardial wall motion in young and elderly individuals using navigator gated tissue phase mapping.

The purpose of this study was to evaluate normal values for regional and global myocardial wall motion parameters in young and elderly individuals, as detected by navigator gated high temporal resolution tissue phase mapping. Radial, longitudinal and circumferential ventricular wall motion, as well as ventricular torsion and longitudinal strain rates, were assessed in two age groups of volunteers, 23 ± 3 (n = 14) and 66 ± 7 years old (n = 9), respectively. All subjects were healthy, non-smokers without known cardiac disease. An increased global left ventricular (LV) torsion rate (peak systolic torsion rate 20.6 ± 2.0 versus 14.5 ± 1.0°/s/cm, peak diastolic torsion rate -25.2 ± 1.8 versus -14.1 ± 1.3°/s/cm) and a decrease in longitudinal LV motion (peak systolic values at mid-ventricle 5.9 ± 0.5 versus 8.5 ± 0.8 cm/s, peak diastolic values -10.7 ± 0.7 versus -15.2 ± 0.9 cm/s) in the older age group were the most prominent findings. Lower peak diastolic radial velocities with a longer time-to-peak values, most pronounced at the apex, are consistent with reduced diastolic function with ageing. Lower peak clockwise and counter-clockwise velocities at all LV levels revealed limitations in resting LV rotational motions in the older group. Significant changes in the undulating pattern of the rotational motions of the left ventricle were also observed. The results demonstrate distinct changes in regional and global myocardial wall motion in elderly individuals. Increased LV torsion rate and reduced LV longitudinal motion were particularly prominent in the older group. These parameters may have a role in the assessment of global LV contractility and help differentiate age-related changes from cardiac disease.

Magnetic resonance imaging predicts survival and occult metastasis in oral cancer: a dual-centre, retrospective study.

The purpose of this study was to investigate the effectiveness of tumour variables measured on magnetic resonance imaging (MRI) to predict 2-year disease-related survival and occult cervical lymph node metastasis in oral carcinoma. In this retrospective, dual-centre study the volume and thickness of tumours were measured using archived MRI staging scans of 199 patients who had curative primary resection for histologically confirmed oral carcinoma. Tumour volume predicted survival when grouped using the median (3.0 cm(3), HR 3.41, p 0.005) and first and third quartiles (0.5 cm(3), HR 8.22, p 0.04; 8.0 cm(3), HR 18.6, p 0.005). Tumour thickness predicted survival using a median of 11.0 mm (HR 2.65, p 0.02). Volume predicted occult cervical lymph node metastasis using a median of 3.0 cm(3) (HR 5.02, p<0.001) and quartiles of 0.5 cm(3) (HR 6.92, p=0.01) and 8.0 cm(3) (HR 11.3, p 0.005); thickness predicted it using a median of 11.0 mm (HR 4.39, p 0.002) and quartiles of 4.0 mm (HR 4.33, p 0.06) and 16 mm (HR 11.9, p 0.003). The thickness and volume of tumour measured on MRI may predict 2-year disease-related survival and occult cervical lymph node metastasis in oral cancer.

A detailed anatomical assessment of the lateral tongue extrinsic musculature, and proximity to the tongue mucosal surface. Does this confirm the current TNM T4a muscular subclassification?

PURPOSE: The current T4a subclassification of the TNM staging system for oral malignancies has been criticised as based almost exclusively on anatomical data. The aim of this study was to provide anatomical confirmation of the muscular constraints of T4a classification of oral tongue tumours. METHODS: A detailed anatomical study describing and measuring the adjacency of the named extrinsic tongue muscles to the lateral tongue surface was completed on the Visible Human Female (VHF). The distance of styloglossus and hyoglossus to the over lying mucosa were determined. RESULTS: The appearance, position, orientation and anatomical relationships of the lateral tongue extrinsic muscles, with comparison to their classical descriptions are described. The right VHF styloglossus was 1.3 mm (0.33-1.48) and left 2.91 mm (0.66-7.68) from the mucosal surface in the axial plane. The right VHF hyoglossus was 2.93 mm (1.48-4.96) and left 4.33 (1.68-8.71) from the mucosal surface in the axial line. CONCLUSIONS: In the lateral tongue, styloglossus and hyoglossus are very superficial. The inclusion criteria of hyoglossus and styloglossus in the T4a staging does not appear justified based upon their anatomical position.

Identification of normal cranial sutures in infants on routine magnetic resonance imaging.

There are increasing concerns relating to the ionizing effects of computed tomography imaging in infants with benign conditions. Magnetic resonance imaging (MRI) is a potential alternative to ionizing radiation when determining patency of the cranial sutures; however, there is no documentation in the literature on the appearance of normal cranial sutures in infants on MRI. This study reviews the appearance of the cranial sutures, their widths, and accuracy of identification in the first year of life on MRI.The coronal, sagittal, and lambdoid sutures were evaluated by 5 assessors on 100 anonymized MRI scans in infants aged 1 to 361 days. The sutures were scored on a 3-point scale. The MRI sequences investigated were axial T1, axial T2, coronal fluid attenuated inversion recovery, axial short tau inversion recovery, and sagittal T1. The suture widths were measured in those cases where they were clearly identifiable, and agreement was obtained in the first aspect of the study (n = 38).A κ score of 0.6 was obtained for interrater agreement. An increasing total score for all sutures with advancing age was found (P < 0.05). The mean suture widths for the coronal, sagittal, and lambdoid sutures were 1.2 (SD, 0.4), 1.4 (SD, 0.4), and 1.3 (SD, 0.3) mm, respectively. There was no significant difference in suture width with age.The appearance of cranial sutures on MRI is as an area of signal void, which may be difficult to clearly define, thus making it unreliable as a standard investigation in the diagnosis of craniosynostosis.

Magnetic resonance imaging-based tumor volume measurements predict outcome in patients with squamous cell carcinoma of the mandible.

OBJECTIVE: The objectives of this study were to determine the benefit of pretreatment magnetic resonance imaging (MRI)-based tumor volume (Tv) measurements in patients presenting with squamous cell carcinomas (SCCs) involving the oral cavity subsites most frequently associated with mandibular bone invasion. STUDY DESIGN: A 10-year retrospective study of all patients undergoing surgical resection for primary SCC of the retromolar trigone, mandible, or floor of mouth (with bone involvement) was completed. In total, 62 patients met the inclusion criteria, and Tv measurements completed on their pretreatment MRI. RESULTS: Tumor volume was significant at predicting all-cause survival and disease-free survival at 5 years. Tv stratification to correlate with the TNM staging system resulted in down-staging in 40 of the 62 cases. CONCLUSIONS: Tumor volume was a more useful predictor of outcome than the current clinical or pathologic TNM staging, considering the automatic up-staging of tumors involving mandibular bone to T4 tumors.

Angioleiomyoma of the hard palate: report of a case and review of the literature and magnetic resonance imaging findings of this rare entity.

Angioleiomyomas are benign solitary smooth muscle tumors originating in the tunica media of vessels. They are rarely encountered within the oral cavity, and the number of reported cases specifically involving the hard palate remains small. A 39-year-old man presented with a 2-cm painless swelling on the left anterior hard palate. The mass had been present for ≈ 5 years before presentation, during which time it had slowly enlarged. Magnetic resonance imaging (MRI) showed a uniform signal pattern with T1 signal intensity slightly higher than surrounding soft tissues and marked hyperintensity on T2-weighted sequences. Although the MRI characteristics of angioleiomyomas affecting the extremities have previously been reported, this is the first reported case describing the MRI features of an oral-cavity angioleiomyoma. In view of the inability to differentiate angioleiomyoma from other pathologies with similar MRI features, simple local excision for definitive histopathologic diagnosis remains recommended.

Longitudinally and circumferentially directed movements of the left ventricle studied by cardiovascular magnetic resonance phase contrast velocity mapping.

OBJECTIVE: Using high resolution cardiovascular magnetic resonance (CMR), we aimed to detect new details of left ventricular (LV) systolic and diastolic function, to explain the twisting and longitudinal movements of the left ventricle. METHODS: Using CMR phase contrast velocity mapping (also called Tissue Phase Mapping) regional wall motion patterns and longitudinally and circumferentially directed movements of the left ventricle were studied using a high temporal resolution technique in healthy male subjects (n = 14, age 23 +/- 3 years). RESULTS: Previously undescribed systolic and diastolic motion patterns were obtained for left ventricular segments (based on the AHA segmental) and for basal, mid and apical segments. The summation of segmental motion results in a complex pattern of ventricular twisting and longitudinal motion in the normal human heart which underlies systolic and diastolic function. As viewed from the apex, the entire LV initially rotates in a counter-clockwise direction at the beginning of ventricular systole, followed by opposing clockwise rotation of the base and counter-clockwise rotation at the apex, resulting in ventricular torsion. Simultaneously, as the entire LV moves in an apical direction during systole, the base and apex move towards each other, with little net apical displacement. The reverse of these motion patterns occur in diastole. CONCLUSION: Left ventricular function may be a consequence of the relative orientations and moments of torque of the sub-epicardial relative to the sub-endocardial myocyte layers, with influence from tethering of the heart to adjacent structures and the directional forces associated with blood flow. Understanding the complex mechanics of the left ventricle is vital to enable these techniques to be used for the evaluation of cardiac pathology.

MRI for definitive in utero diagnosis of cleft palate: a useful adjunct to antenatal care?

OBJECTIVE: To assess the use of fetal magnetic resonance imaging (MRI) in obtaining a definitive prenatal diagnosis of cleft palate. DESIGN: All expectant mothers with a sonographically diagnosed fetal cleft lip or a previously affected child with cleft palate were offered antenatal MRI at around 34 weeks' gestation. Images were interpreted by a consultant radiologist who was blinded to the ultrasound diagnosis. Two MRI readings were performed: one at the time of examination and one at the end of the study to elicit the radiologist's learning curve. MRI findings were correlated with the birth diagnosis. SETTING: Tertiary referral center for facial clefts--the Spires Cleft Centre, Oxford Children's Hospital, Oxford, United Kingdom. PARTICIPANTS: Study participants included 49 pregnant women between 24 and 37 weeks' gestation, four with a family history of cleft posterior palate and 45 with a facial cleft on a 20-week ultrasound. RESULTS: The positive predictive value of fetal MRI for involvement of the palate was 96%, and the negative predictive value was 80%. The accuracy in predicting palatal clefting of four different MRI signs is discussed. The radiologist's interpretation skills significantly improved between the two MRI readings. CONCLUSIONS: Fetal MRI enables us to predict accurately the extent of a cleft palate after an ultrasound diagnosis of cleft lip. With more accurate diagnosis of the severity of the cleft, we can counsel patients more precisely and plan postnatal management correctly.

Patterns of ovarian morphology in polycystic ovary syndrome: a study utilising magnetic resonance imaging.

OBJECTIVE: To evaluate and compare MRI-based ovarian morphology in groups of women with polycystic ovary syndrome (PCOS) and controls. METHODS: All PCOS cases (n = 44) had oligo-amenorrhoea and hyperandrogenism irrespective of ovarian morphology, and fulfilled NIH/Rotterdam diagnostic criteria for PCOS. All control women (n = 40) had normal menses and normoandrogenaemia. All subjects were of white British/Irish origin and pre-menopausal. Group comparisons were based on independent-sample t tests. Polycystic ovarian morphology was defined by at least 12 follicles 2-9 mm in diameter and/or an ovarian volume greater than 10 cm(3). RESULTS: Ovarian morphology differed significantly in PCOS cases and controls (follicle number geometric mean [SD range] 18.6 [9.9, 35.0] vs 6.6 [3.1, 14.2], unadjusted P = 1.3 x 10(-16); calculated ovarian volume 8.8 cm(3) [5.0, 15.5] vs 5.1 cm(3) [2.5, 10.3], unadjusted P = 3.0 x 10(-7); peripheral follicle location in 55% vs 18% of ovaries, P = 7.9 x 10(-6); visible central ovarian stroma in 61% vs 24% of ovaries, P = 2.3 x 10(-5)). Follicle number and calculated ovarian volume were not concordant with clinical/biochemical assignment of PCOS/control status in 36 (23%) and 52 (34%) of ovaries, respectively. CONCLUSION: Ovarian morphology overlaps in PCOS cases and controls, emphasising the importance of considering clinical/biochemical presentation together with imaging ovarian morphology in the diagnosis of PCOS.

Serum levels of retinol-binding protein 4 and adiponectin in women with polycystic ovary syndrome: associations with visceral fat but no evidence for fat mass-independent effects on pathogenesis in this condition.

CONTEXT: Insulin resistance, which associates with levels of retinol-binding protein 4 (RBP4) and adiponectin, is implicated in the development of polycystic ovary syndrome (PCOS). OBJECTIVE: The objective of the study was to explore the potential contribution of RBP4 and adiponectin in the etiology of PCOS and their relationships with specific fat depot measurements. DESIGN: This was a cross-sectional study. SETTING AND PARTICIPANTS: Serum RBP4 and adiponectin levels were compared between 50 PCOS cases and 28 female controls (including 22 body mass index/fat mass-matched pairs) and correlated with specific fat depot (including visceral) axial magnetic resonance imaging cross-sectional area measurements. All subjects were of U.K. British/Irish origin. MAIN OUTCOME MEASURE(S): Serum levels of RBP4 (automated immunonephelometric assay) and adiponectin [immunoassay: total and high molecular weight (HMW)]. Data are reported as geometric mean (sd, range) and optionally adjusted for fat mass and age. RESULTS: Between the 50 PCOS cases and 28 controls, serum RBP4 levels were indistinguishable [39.0 microg/ml (31.0, 49.0) vs. 41.6 microg/ml (32.7, 52.9), respectively, unadjusted P = 0.24; adjusted P = 0.55]. Total (and HMW) adiponectin levels were lower in PCOS cases [total adiponectin 19.9 microg/ml (14.2, 27.8) vs. 25.8 microg/ml (17.7, 37.7), respectively, unadjusted P = 2.4 x 10(-3); adjusted P = 0.10]. For the paired-sample analyzes, there were no differences in RBP4 (P = 0.09), total adiponectin (P = 0.06), HMW adiponectin (P =0.19), or HMW to total adiponectin ratio (P = 0.98). In PCOS cases, L4-visceral fat area was associated positively with RBP4 (r(2) = 0.34, P = 0.01) and negatively with HMW to total adiponectin ratio (r(2) = -0.44, P = 1.3 x 10(-3)). Controls showed similar relationships. CONCLUSIONS: Although associated with visceral fat, serum RBP4 and adiponectin levels do not play important, fat-mass-independent primary roles in the development of PCOS.

Global adiposity rather than abnormal regional fat distribution characterizes women with polycystic ovary syndrome.

CONTEXT: Obesity-related predisposition to polycystic ovary syndrome (PCOS) could reflect overall adiposity and/or regional accumulation of abdominal visceral fat. OBJECTIVE: The objective of the study was to compare distributions of visceral, abdominal sc, and gluteofemoral sc adipose tissue in PCOS cases vs. control women. DESIGN: This was a cross-sectional study. SETTING AND PARTICIPANTS: Fat depot measurements from axial magnetic resonance imaging scans taken at anatomically predefined sites were compared between 22 body mass index (BMI)/fat mass-matched pairs of PCOS cases and controls; whole-group comparisons included 50 PCOS cases vs. 28 female controls. All subjects were of UK British/Irish origin. MAIN OUTCOME MEASURE(S): We measured cross-sectional areas of adipose tissue within visceral (mid-L4), abdominal (mid-L4) sc, and gluteofemoral (greater trochanteric and midfemoral) sc fat depots. Other measurements included fat mass, BMI, testosterone, SHBG, and homeostasis model assessment of insulin resistance (a measure of insulin sensitivity). Whole-group analyses were adjusted for fat mass and age. RESULTS: There were no significant differences in fat-depot measurements between BMI/fat mass-matched pairs of PCOS cases and controls: mid-L4 visceral (P=0.40), abdominal sc (P=0.22), gluteal sc (P=0.67), and midfemoral sc (P=0.37) depots. Whole-group comparisons gave similar results after adjustments for fat mass and age. Fasting serum insulin concentrations (P=0.03) and homeostasis model assessment of insulin resistance (P=0.03) were significantly higher in the PCOS group than BMI/fat mass-matched controls. CONCLUSIONS: PCOS cases and BMI/fat mass-matched control women are indistinguishable with respect to distribution of fat within visceral, abdominal sc, and gluteofemoral sc depots, despite significant differences in insulin resistance between these two groups.

Multi-slice computed tomography (MSCT): the dose challenge of the new revolution.

Multislice computed tomography (MSCT) has dramatically increased the flexibility and availability of computed tomography (CT), so that the technique is being used increasingly across a widening range of applications. However CT still remains a technique with high absorbed radiation dose, and contributes an increasingly greater proportion of the total collective dose from man-made sources of radiation. Many, but not all, new applications are supported by clinical benefit. Additionally, the examination technique parameters vary widely but not always with apparent justification. There is currently a weak evidence base for reducing the absorbed dose from CT to the threshold necessary to provide clinically relevant findings and research is needed urgently in this area. In the interim, advice from guidelines such as those published by the European Commission should be followed.