Keep your eyes on the ribs: the spectrum of normal variants and diseases that involve the ribs

Osteoblast differentiation of murine embryonic stem cells as a model to study the embryotoxic effect of compounds

The embryonic stem cell test (ESTc), in which the effect of chemical compounds on cardiomyocyte differentiation is evaluated, is one of the most studied in vitro alternatives for developmental toxicity testing. Because the assay readout is restricted to a single endpoint of differentiation, compounds that affect alternative differentiation pathways might be overlooked. It has therefore been suggested that the predictive value of the EST may be improved by including alternative differentiation endpoints. The aim of the present study was to evaluate the effect of five teratogenic compounds as well as one non-teratogenic compound on the differentiation of murine embryonic stem cells into osteoblasts (ESTo) and to compare results with those in the classical ESTc. We established an ESTo assay which proved robust, stable and reproducible. In this study, we showed that the evaluated compounds affected osteoblast differentiation both at the level of calcium concentrations in the culture as well as on multiple gene expression. Furthermore, we showed that the effect on calcium concentrations appeared to be primarily mediated by a general apoptotic effect and not by a specific effect on differentiation. The compounds tested showed little difference in their potency in the ESTo as compared to the ESTc. Before a definitive statement can be made regarding the added value of including an osteoblast differentiation endpoint into the EST, more compounds need to be evaluated.

Radiology of chest wall masses

OBJECTIVE

The purpose of this article is to highlight the role of radiography, CT, PET/CT, and MRI in the diagnosis and management of chest wall lesions. Chest wall masses are caused by a spectrum of clinical entities. The lesions highlighted in this selection of case scenarios include neoplastic, inflammatory, and vascular lesions.

CONCLUSION

Imaging evaluation with radiography, CT, MRI, and PET/CT plays an important role in the accurate diagnosis of chest wall lesions. It can also facilitate percutaneous biopsy, when it is indicated. Imaging enables accurate staging and is a key component of treatment planning for chest wall masses.

Short review: field recovery and potential information value of small elements of the skeleton

The recovery of small elements of the skeleton (e.g. hyoid, carpals, and hand and foot phalanges) is one of the established tasks of the archaeologist and physical anthropologist when working in the field, whether in an archaeological or forensic context. In the present work, we illustrate the field location of ossified laryngeal cartilages, hand sesamoids, and the medial clavicular epiphyses. The potential information offered by these elements is briefly summarized. The frequency of these elements observed in a cemetery dating from 1943 indicates the possibility that these elements could be found in other contexts at a higher frequency than expected.

CT of rib lesions

OBJECTIVE

This article discusses how ribs are involved in a variety of traumatic, metabolic, inflammatory, neoplastic, and congenital disorders.

CONCLUSION

We review the normal anatomy pertinent to rib imaging and illustrate the key features of a variety of rib lesions, emphasizing the diagnostic value of CT.

Prenatal diagnosis of isolated abnormal number of ribs

OBJECTIVE

To determine the incidence of prenatal isolated abnormal number of ribs, using three-dimensional (3D) ultrasound.

METHODS

This was a prospective study of low-risk women with singleton pregnancy and normal fetal anatomy scan. 3D examinations of the fetal ribs were carried out at the time of the routine anomaly scan at 14-16 or 20-24 weeks of gestation. A 3D volume of the spine was acquired with a mechanical sweep that lasted between 2 and 4 s per volume and was performed when the fetus had a minimally flexed head position. Fetal ribs were reviewed on the rendered image (maximal mode), both while the patient was in the clinic and again later.

RESULTS

Three hundred and sixty-seven pregnant women were evaluated. Twenty-three (6.3%) fetuses were found to have an abnormal number of ribs. Fifteen (4.1%) had 11 ribs unilaterally, with the last (12(th)) rib missing. One patient (0.27%) had 13 ribs unilaterally (with a small extra rib after the last rib). Two (0.5%) patients had 13 ribs bilaterally with an extra rib after the 12(th) rib on each side and two (0.5%) patients had 13 ribs bilaterally with an extra cervical rib on each side. Three (0.8%) patients had an extra unilateral cervical rib. In all, 1.4% of patients had extra cervical ribs.

CONCLUSIONS

The incidence of abnormal number of ribs in this normal population was 6.3%. When isolated, this finding is a normal variant.

Sonography for diagnosis of cervical ribs in children

OBJECTIVE

The purpose of this series was to describe the use of sonography for diagnosis of cervical ribs in children.

METHODS

Two children had hard nonmobile supraclavicular masses that were of clinical concern for malignancy. Both children were first evaluated by sonography.

RESULTS

Sonography showed each mass to be a tubular bony structure with a cartilaginous end. They were thought to represent cervical ribs. This anatomic variant was subsequently confirmed with radiography in 1 case and computed tomography in the other.

CONCLUSIONS

Musculoskeletal sonography may offer a reliable method for diagnosing cervical ribs without the need for ionizing radiation.

A complex congenital anomaly: liver eventration because of intrathoracic rib and vertebral segmentation disorder--a case report

The complicated processes of chest development and differentiation frequently lead to malformations of the ribs and vertebrae. An intrathoracic rib is a rare anomaly. We report here, for the first time, a complex congenital malformation with liver eventration because of a right intrathoracic rib and vertebral segmentation disorder of the spine in a 7-year-old girl without respiratory impairment. Diagnostic features and therapy for congenital rib anomalies are described.

Altered axial skeletal development

The axial skeleton is routinely examined in standard developmental toxicity bioassays and has proven to be sensitive to a wide variety of chemical agents. Dysmorphogenesis in the skull, vertebral column and ribs has been described in both human populations and in laboratory animals used to assess potential adverse developmental effects. This article emphasizes vertebrae and rib anomalies both spontaneous and agent induced. Topics discussed include the morphology of the more common effects; incidences in both human and experimental animal populations; the types of anomalies induced in the axial skeleton by methanol, boric acid, valproic acid and others; the postnatal persistence of common skeletal anomalies; and the genetic control of the development of the axial skeleton. Tables of the spontaneous incidence of axial anomalies in both humans and animals are provided.

On the trail of pulmonary tuberculosis based on rib lesions: Results from the human identified skeletal collection from the Museu Bocage (Lisbon, Portugal)

In the last 20 years, studies on human identified skeletal collections have revealed a significant relationship between new bone formation on the visceral surface of ribs and pulmonary tuberculosis (TB). To improve methods of differential diagnosis of respiratory diseases in archaeological skeletons, an investigation was conducted on 197 individuals from the Human Identified Skeletal Collection of the Museu Bocage (Lisbon, Portugal). This sample included 109 males and 88 females who lived during the 19th-20th centuries, with ages at death ranging from 13-88 years. The skeletons were grouped according to cause of death: 1) pulmonary TB (N = 84); 2) pulmonary non-TB diseases (N = 49); and 3) a control group (N = 64) composed of individuals randomly selected among the extrapulmonary non-TB causes of death. The ribs, sterna, scapulae, and clavicles were macroscopically observed. New bone formation on the visceral surface of ribs was recorded in 90.5% (76/84) of individuals who died from pulmonary TB, in 36.7% (18/49) with a pulmonary non-TB disease as cause of death, and in 25.0% (16/64) of the control group. These differences were statistically significant (P < 0.001). Furthermore, in individuals with pulmonary TB, the bony lesions presented mainly as lamellar bone on the vertebral end of the upper and middle thoracic rib cage. Proliferative alterations also occurred on one sternum and in nine clavicles and eight scapulae. This work strongly supports the results of similar studies performed on other documented collections, suggesting that new bone formation on ribs, although not pathognomonic, is a useful criterion for the differential diagnosis of pulmonary TB.

Segmentation of the posterior ribs in chest radiographs using iterated contextual pixel classification

The task of segmenting the posterior ribs within the lung fields of standard posteroanterior chest radiographs is considered. To this end, an iterative, pixel-based, supervised, statistical classification method is used, which is called iterated contextual pixel classification (ICPC). Starting from an initial rib segmentation obtained from pixel classification, ICPC updates it by reclassifying every pixel, based on the original features and, additionally, class label information of pixels in the neighborhood of the pixel to be reclassified. The method is evaluated on 30 radiographs taken from the JSRT (Japanese Society of Radiological Technology) database. All posterior ribs within the lung fields in these images have been traced manually by two observers. The first observer's segmentations are set as the gold standard; ICPC is trained using these segmentations. In a sixfold cross-validation experiment, ICPC achieves a classification accuracy of 0.86 +/- 0.06, as compared to 0.94 +/- 0.02 for the second human observer.

Anatomy of a serial killer: Differential diagnosis of tuberculosis based on rib lesions of adult individuals from the Coimbra identified skeletal collection, Portugal

The role of new bone formation on visceral surfaces of ribs in the diagnosis of tuberculosis (TB) in past human populations has been explored by many researchers, using both skeletal remains with known causes of death and archaeological samples. This study focuses, firstly, on adult skeletons from the Coimbra Identified Skeletal Collection in Portugal and investigates the skeletal manifestations of individuals known to have died from TB; secondly, this study focuses on the role of rib lesions in the diagnostic criteria for TB. One hundred and fifty-seven males and 106 females aged between 22-87 years were examined; causes of death were assigned as pulmonary TB, extrapulmonary TB, and pulmonary non-TB; a control group, extrapulmonary non-TB, was selected from the remaining individuals. Of individuals with rib lesions, 85.7% (69/81) had pulmonary or extrapulmonary TB as an assigned cause of death, while 17.8% (16/90) of individuals with rib lesions had a non-TB cause of death. Rib lesions were significantly more common in individuals who had died from TB, although the lesions cannot be considered pathognomonic for TB. In individuals dying from pulmonary TB, ribs in the central part of the rib cage were most affected, at their vertebral ends. The lower part of the rib cage may be a marker for peritoneal TB, and "coral-like" new bone formation on ribs may be an indicator of neoplastic disease. Further work on rib involvement in TB in clinical contexts, and the study of further documented skeletal collections, are recommended.

Imaging Evaluation of Chest Wall Disorders in Children

This article discusses the imaging evaluation of chest wall disorders in children.

Supernumerary ribs in developmental toxicity bioassays and in human populations: incidence and biological significance

Supernumerary or accessory ribs (SNR), either lumbar (LR) or cervical (CR), are a common finding in standard developmental toxicology bioassays. The biological significance of these anomalies within the regulatory arena has been problematic and the subject of some debate. In rodents, the spontaneous incidence of SNR is species and strain related and ranges from <1% to >30%. Compound-induced LR are induced by a wide variety of chemical and physical agents when pregnant animals are exposed during specific gestational periods. A significant portion of the agent-induced LR may be due to maternal factors, as it has been shown that stress alone will induce LR in rodents. SNR are not isolated phenomena and signify basic alterations in the architecture of the axial skeleton. LR are associated with longer ribs, increased numbers of vertebrosternal ribs, and the presence of extra presacral vertebrae ("anteriorization"). CR are associated with reduced numbers of vertebrosternal ribs (posteriorization). It is evident that SNR are not a single anomaly, but consist of two unrelated structures: an extra rib that has a cartilaginous segment at the distal end, and an ossification site that lacks cartilage. These have a bimodal size distribution, with the population of extra ribs being significantly longer than the ossification sites, and 0.6 mm can be used as an approximate length for distinguishing the two populations in mice. Extra ribs are permanent structures in contrast to ossification sites that disappear postnatally, probably becoming part of the lateral transverse vertebral processes. SNR are also found in humans although, in contrast to laboratory species, CR are more commonly noted. SNR are associated with adverse heath effects, and CR with inducing thoracic outlet disease characterized by diminished blood flow and altered position of the ganglia and nerve roots in the area of the C7-T1 vertebrae. LR are associated with lower back pain and L4-5 degeneration. The incidence of CR is greatly reduced in adult humans as compared to fetuses, and it has been hypothesized that fetal "SNR" may be largely composed of ossification sites that disappear postnatally. The mechanisms involved in the formation of extra ribs are not understood at this time, although the fact that the early sensitive periods for their initiation during embryogenesis is coupled with the associated changes in the axial skeleton argues for their induction being due to fundamental changes in gene expression. The sum of the experimental evidence supports the idea of SNR being composed of two different structures: extra ribs that are permanent dysmorphological structures that may be induced by xenobiotics and/or maternal stress, and ossification sites that may be transient variations in the formation of the lateral processes of the vertebrae.

Solitary hot spots in the ribs on bone scan: value of thin-section reformatted computed tomography to exclude radiography-negative fractures

PURPOSE

The purpose of this study was to classify solitary, scintigraphy-positive and radiography-negative rib lesions and to clarify the features of rib fractures by using thin-section reformatted helical computed tomography (CT).

METHODS

Forty-seven patients whose whole-body bone scans showed a solitary hot spot in a rib as their first abnormal scintigraphic finding and whose plain radiograph showed negative or indeterminate results were examined by thin-section reformatted CT. Final diagnosis was based on follow-up over a 20-month period.

RESULTS

The final diagnosis included 17 cases of fractures where CT findings were fracture line, focal sclerosis, and callus formation. Fourteen ribs demonstrated intramedullary, focal osteosclerosis, and 8 ribs did not demonstrate any abnormalities. Four metastatic lesions appeared as intramedullary mixture of osteolysis and osteosclerosis, or bone destruction. Four intramedullary lesions with cystic appearance remained unchanged.

CONCLUSIONS

Thin-section reformatted helical CT delineated minute, radiographically occult fractures of the rib. Excluding fractures, helical CT can avoid further unnecessary examinations.

Pediatric ribs: a spectrum of abnormalities

The manifestations of many congenital and acquired conditions can be seen in the ribs of children. Normal variants are usually clinically insignificant; they are occasionally palpated at clinical examination or detected incidentally at chest radiography. Signs of abnormality can appear in the ribs as variations in number, size, mineralization, and shape. These changes can be focal or generalized. Abnormalities detected in the ribs may be the initial indication of previously unsuspected systemic disease. The ribs can yield important diagnostic clues in the work-up of patients with congenital bone dysplasias, acquired metabolic diseases, iatrogenic conditions, trauma (especially child abuse), infection, and neoplasms. Routine evaluation of the ribs on every chest radiograph is important so that valuable diagnostic data will not be overlooked. The diagnostic information obtained from evaluation of the ribs can help tailor the radiologic and laboratory studies that may be necessary to complete a patient's diagnostic work-up.