Rates of growth of human neoplasms: Part II

Part I of this study [Spratt JS, Meyer JS, Spratt JA: J Surg Oncol 60:137-146, 1995] reviewed the early reports of investigators, predominantly mathematical biologists and statisticians considering the mathematical laws that would describe the growth of a neoplasm. Included were cytokinetic measurements of the mitotic index, thymidine labeling index, bromodeoxy-uridine labeling index, and the relation of these indices to the potential tumor volume doubling time. The actual doubling time of benign and malignant colonic neoplasms were reported. This second part provides the cumulative observations on the actual doubling times of pulmonary metastases, primary pulmonary cancers, skeletal sarcomas, melanomas, a chemodectoma, tumors of maxillary antrum, testicular cancers, prostate cancer, and the relation between the accumulation of multiple primary cancers and growth rates. The most complete data set is for breast cancer concluding that the cancer growth curve is a decelerating curve with great natural variance. Understanding of the rates of growth of human cancers is essential for understanding the spectrum of cancer behavior observed clinically.

Cognitive performance after small strokes correlates with ischemia, not atrophy of the brain

Computerized tomographic measures of recurrent cerebral infarctions, atrophy and local perfusion were all prospectively correlated with cognitive testing during treatment of risk factors plus antiplatelet therapy among vascular dementia patients. Neurological and cognitive status were quantified among 22 demented patients with small strokes and compared with 22 age-matched normal volunteers. In vascular dementia, risk factor control plus antiplatelet therapy reduced cerebral infarctions, increased perfusion, and stabilized or improved cognitive test performance, despite age-related, progressive cerebral atrophy.

Functional brain imaging

Images

Ovarian torsion: clinical and imaging presentation in children

Ovarian torsion is uncommon and has a nonspecific clinical presentation. To determine the impact of imaging on clinical management, the authors reviewed their recent experience with 12 children who had a total of 13 episodes of ovarian torsion. Three children presented as neonates, six were premenarchal, and three were postmenarchal. Ultrasound was the imaging study of choice. In all three neonates, ultrasonography showed complex abdominopelvic cysts indicating the need for surgery. In five of 10 episodes in older patients, ultrasonography showed a solid mass with an appearance strongly suggestive of torsion. Same-day surgery was performed in three patients, and the involved ovary was salvaged in one. Another patient had a small piece of normal-appearing ovary left in situ. This low rate of ovarian salvage is attributable to the combination of delay in patient presentation and surgical delay owing to the often nonspecific clinical and imaging presentation of ovarian torsion. A high level of clinical suspicion, expeditious imaging, and familiarity with the varied clinical and imaging presentations of ovarian torsion should decrease the surgical delay and improve the likelihood of ovarian salvage.

Cerebral density and perfusion measured among heart disease patients with and without stroke

This investigation was designed to clarify the chronic effects of cardiogenic emboli on cerebral perfusion and tissue densities within remaining noninfarcted brain. Local cerebral perfusion and tissue densities were measured by xenon-contrasted CT scanning and compared by cross-sectional designs among normal volunteers without heart disease (Group C, n = 44), normal volunteers with heart disease (Group N, n = 20), patients with heart disease and lacunar infarctions (Group L, n = 31) and patients with heart disease associated with cardiogenic cerebral embolism (Group E, n = 12). In Group E, remaining cortical and subcortical gray and white matter perfusion were reduced compared to Groups C and N (p = 0.01), but did not differ from Group L, who had similar profiles of risk factor for stroke. In Group E, perfusion was reduced within the thalamus ipsilateral to cortical infarctions (p < 0.05). There were no differences in remaining tissue densities between Groups E and L. It is concluded that reduced cerebral perfusion in noninfarcted regions among patients with cardiogenic emboli appears to be related to atherosclerosis of small cerebral vessels in a similar manner to patients with lacunes, but thalamo-cortical disconnections also contribute to cerebral hypoperfusion.

Rates of growth of human solid neoplasms: Part I

The purpose of this article is to consolidate data collected from a variety of sources that have permitted calculations of the rates of growth of human neoplasms. These sources include Fischel State Cancer Hospital (Columbia, MO); Mallinckrodt Institute of Radiology, (St. Louis, MO); Roentgen Diagnostic Institute, Allmanna Sjukhuset (Malmo, Sweden); University of Louisville (Louisville, Kentucky); University of Heidelberg (Heidelberg, Germany); and St. Luke's Hospital (St. Louis, MO). Included in the data are laboratory measurements of cell replication rates. All gross measurements were made either on imaging studies or with a centimeter scale for surface or palpable neoplasms. Data have been reported for breast and pulmonary cancers and metastases of many types, melanomas, skeletal sarcomas, benign and malignant colonic neoplasms, and isolated cases of less frequent neoplasms. Related cytokinetic measurements by tritriated thymidine labelling, bromodeoxyuridine labelling, S-phase fraction from DNA flow cytometric analysis, and mitotic indices are discussed. The various mathematical formulae applicable to the analysis of the collected data and the determination of rates and patterns of growth are included. Also considered are the clinical implications of these data and the importance of ever better knowledge on the cytokinetics of human cancer. Prior studies on the evolution of insight into this field are cited and discussed. The authors conclude that a more accurate quantification of the growth rates of human cancer is essential for understanding the biological variance of human cancers seen clinically.

Proliferative rate by S-phase measurement may affect cure of breast carcinoma

BACKGROUND

Standard, nonparametric statistical methods measure the interaction of covariates with survival rate or relative risk. Conversely, parametric methods measure the interaction of covariates with the two cardinal features of malignant potential: the likelihood of cure and the median time to relapse among uncured patients.

METHODS

The authors performed parametric analysis on data from 810 patients with breast cancer using relapse as the survival end point. Prognostic covariates included lymph node status, tumor size, patient age, nuclear size, S-phase by thymidine or bromodeoxy-uridine labeling, and type of adjuvant therapy (chemotherapy, radiation, or hormone therapy). Also included was the cross-product term (labeling index X chemotherapy).

RESULTS

Multivariate analysis revealed that: likelihood of cure was associated positively with labeling index X chemotherapy and associated negatively with lymph node status, tumor size, and patient age; and time to relapse was associated negatively with node status, nuclear size, and labeling index.

CONCLUSION

The associations of labeling index and chemotherapy with the clinical course suggest that rapidly dividing tumors have a high likelihood of cure, especially with adjuvant chemotherapy, but those not cured may have early relapse.

Langerhans cell histiocytosis: presentation and evolution of radiologic findings with clinical correlation

Radiologic images and medical records of 42 children with Langerhans cell histiocytosis (LCH) (histiocytosis X) were reviewed to evaluate the presentation of the disease and the evolution of the radiologic findings. There were 26 male and 16 female patients aged 3 months to 18 years. Twenty-two patients presented with localized disease; 20 presented with multifocal disease. Four patients developed diabetes insipidus. Two patients had organ dysfunction. The radiologic findings were largely due to destructive bone lesions; 83% of the patients had at least one affected bone. Isolated soft-tissue masses, interstitial lung disease, and central nervous system abnormalities were also seen. Of patients in whom results of appropriate follow-up were available, 91% showed improvement in their lesions, 43% developed new lesions, and 92% had good clinical outcomes. LCH is usually a self-limited disease with a varied clinical and radiologic presentation. The prognosis is generally poor in children with organ dysfunction. In the absence of organ dysfunction, children with either localized or multifocal LCH have an excellent prognosis.

MRI of focal fibrocartilaginous dysplasia

Focal fibrocartilaginous dysplasia (FFCD) is an uncommon, benign condition associated with unilateral tibia vara in young children. The clinical, pathologic, plain film, and magnetic resonance imaging (MRI) findings of FFCD were reviewed in two children. MRI findings were virtually identical in both patients and correlated well with the plain film and pathologic findings. We believe that FFCD has a typical MRI appearance. However, FFCD also has characteristic plain film findings, and when these are present, MRI is indicated for only an atypical clinical presentation.

Prospective CT confirms differences between vascular and Alzheimer's dementia

BACKGROUND AND PURPOSE

Cognitive test performances were correlated prospectively with changes in cerebral CT measurements of atrophy, infarct volume, ventricular enlargement, local tissue density, and local perfusion to contrast annual rates of changes among patients with ischemic vascular dementia (IVD) or dementia of the Alzheimer type (DAT).

METHODS

The cerebral atrophic index (ATI; ratio of cerebrospinal fluid or infarcted brain to intracranial volume), infarct volume ratio, ventricular volume ratio (VVR; ventricular volume/intracranial volume), cortical and subcortical gray and white matter local perfusion (local cerebral blood flow [LCBF]), and local Hounsfield unit (HU) density were measured concurrently and compared longitudinally with Cognitive Capacity Screening Examinations (CCSE) scores among 24 treated IVD (age, 68.2 +/- 9.7 years; follow-up, 42 +/- 27 months) and 24 DAT patients (age, 74.2 +/- 6.2 years; follow-up, 30 +/- 19 months).

RESULTS

IVD annual changes were as follows: CCSE, +1.2 +/- 5.9; ATI, +2.1%/y; VVR, +3.2%/y; and LCBF in the subcortical basal ganglia, -0.74 mL.100 g-1.min-1.y-1 (-1.8%/y). DAT annual changes were as follows: CCSE, -1.8/y; ATI, +8.1%/y; VVR, +9.6%/y; cortical LCBF, -2.0 mL.100 g-1.min-1.y-1 (-5.2%/y); LCBF in the basal ganglia, -3.0 mL.100 g-1.min-1.y-1 (-6.7%/y); white matter LCBF, -0.75 mL.100 g-1.min-1.y-1 (-4.1%/y); and all cortical tissue densities, -0.83 HU/y (-2.1%/y). In IVD, multiple regression analyses correlated cognitive changes directly with (1) recurrent silent infarctions and (2) bidirectional changes of perfusions within frontal white matter, thalamus, and internal capsules. In DAT, cognitive declines correlated with cerebral atrophy and cortical hypoperfusion related to frontotemporal and parietal cortical polioaraiosis (decreased gray matter tissue densities).

CONCLUSIONS

In IVD, recurrent strokes were not observed clinically during risk factor control, and antiplatelet therapy and cognitive impairments improved or stabilized. In DAT, cognitive performance relentlessly declined. Ischemic pathogenesis for vascular dementia is supported by the following: (1) cognitive declines correlate directly with recurrent "silent" strokes, and (2) bidirectional cognitive changes correlate directly with frontal white matter, thalamic, and internal capsular perfusional changes.

Education and occupation as risk factors for dementias of the Alzheimer and ischemic vascular types

Education and occupation as sociodemographic risk factors for dementias of the Alzheimer (DAT) and ischemic vascular types (IVD) were evaluated by two case series studies. Cases were compared to well-evaluated individuals identified as healthy normals acting as controls. There were 150 patients with probable DAT, 102 patients with probable IVD, and 188 neurologically and cognitively normal subjects. Logistic regression indicated that for DAT, education with occupation was the best predictor (OR, 1.51; 95% CI, 1.23-1.87). For IVD, the two predictors were: education with occupation (OR, 1.84; 95% CI 1.38-4.50) and education with gender (OR, 3.40; 95% CI, 1.29-8.92). We conclude that risk of dementia is increased in those with limited educational background and occupational achievement.

Lack of postmenopausal estrogen replacement therapy and the risk of dementia

Estrogen replacement therapy (ERT) and associated risks for ischemic vascular dementia (IVD) and dementia of the Alzheimer's type (DAT) among postmenopausal women were investigated by determining whether ERT was differently distributed among control subjects than among subjects with dementia. Subjects included 93 with probable DAT, 65 with probable IVD, and 148 normal control subjects. The proportion of control subjects on ERT was almost 2:1, and this ratio holds for both dementia groups. Logistic regression suggests lack of ERT is associated with increased risk for dementia among elderly women. ERT may eventually prove to be a useful prophylactic agent for reducing risk of DAT and IVD among postmenopausal women.

Cognitive declines correlate with decreased cortical volume and perfusion in dementia of Alzheimer type

Cerebral CT changes are correlated with cognitive declines among 18 patients with probable dementia of Alzheimer type (DAT) (7 men, 11 women, mean age 75.4 years) and are compared for control purposes with similar measures among 18 age-matched normal volunteers (8 men, 10 women, mean age 73.7 years). Mean follow-up intervals are 28.6 months for DAT and 27.0 months for controls. For DAT, annual rates for ventricular volume enlargement are +9.2% and for cortical atrophy are -2.1%. Annual reductions in regional cerebral perfusions per 100 g brain/min, are: total cortex -1.1 ml, frontal -1.2 ml, temporal and parietal -0.9 ml, basal ganglia -1.6 ml, thalamus -2.5 ml, total white matter -0.6 ml, frontal white matter -0.7 ml. At entry evaluation, compared to normals, DAT patients had reduced CT densities in white matter, but not in cortex. Nevertheless, cortical CT densities declined progressively at annual rates of -0.72 Hounsfield units (HU), but remained constant in white matter. Annual point score declines for Cognitive Capacity Screening Examinations were -2.0 and for Mini Mental State: -2.8. Controls showed no cognitive change. Multiple regression analyses correlate cognitive declines with: (1) reductions in perfusion within parietal cortex (p = 0.015), (2) decreases in cortical volume (p = 0.019), and (3) decreases in HU within subcortical gray matter (p = 0.007).

S-phase fraction and nuclear size in long term prognosis of patients with breast cancer

BACKGROUND

S-phase fraction (SPF) predicts the prognosis of patients with breast cancer independently of tumor size, axillary metastasis, estrogen receptor (ER) and progesterone receptor (PgR), and patient age. Whether SPF is best measured by DNA labeling index (SPF-LI) or by flow cytometry (SPF-Flow) and what is the relative efficacy of SPF versus histopathologic characteristics for prognosis have remained unanswered questions.

METHODS

The authors studied 845 women with Stages I-II disease classification for years 1975-1990 with end results data, who were treated surgically with axillary lymph node dissection by an in vitro DNA labeling index protocol with tritiated thymidine or 5-bromo-2'-deoxyuridine and whose SPF was measured microscopically. Nuclear size was estimated with a calibrated optical grid as less than 11 microns, 11-14 microns, or greater than 14 microns. DNA flow cytometry was performed on fresh or paraffin embedded tissue; ER and PgR were performed by cytosol assay. Kaplan-Meier survival plots and multivariate analysis were used for comparisons.

RESULTS

Tumor size, axillary lymph nodal status, SPF-LI, nuclear size, and ER all related strongly to breast cancer specific survival and relapse free survival. PgR was less effective. Lymph node status and tumor size predicted long term survival; differences for other variables largely disappeared by 10 years. By multivariate analysis, axillary lymph node status, tumor size, and ER were independently prognostic for disease specific, relapse free survival. A strong trend was found for nuclear size. PgR, DNA ploidy, and SPF did not contribute to prognosis independently. Nuclear size was the strongest independent predictor in patients with negative axillary lymph nodes.

CONCLUSIONS

The number of positive axillary lymph nodes, tumor size, ER, and nuclear size were the strongest predictors of prognosis for patients with breast cancer. Only tumor size and lymph node status predicted the long term risk of metastasis.

Assessment of proliferating cell nuclear antigen (PCNA) in breast cancer using anti-PCNA PC10 and 19A2: correlation with 5-bromo-2'-deoxyuridine or tritiated thymidine labeling and flow cytometric analysis

We compared immunohistochemical staining by two monoclonal antibodies, PC10 and 19A2, to standard methods for cell proliferation, 3H-TdR or BrdU labeling index (S-LI) and S-phase fraction by flow cytometry (S-flow). One hundred thirty-two breast carcinomas were studied retrospectively using formalin fixed, paraffin embedded archival tissues on which S-LI and S-flow had been obtained originally. Percentages of tumor cells positive with PC10 and 19A2 correlated well (r = 0.736, p < 0.0001), although the mean marking index for 19A2 was lower and closer to reference measurements than the mean PC10 index. Correlations between PC10 or 19A2 vs. S-LI, S-flow or DNA ploidy (DNAI) were significant in a group of 64 tumors obtained between 1988 and June 1992, and poor in another group of 68 tumors obtained between 1985 and 1988, suggesting deterioration of stainability with prolonged storage. Discrimination of faint staining from negative nuclei was difficult on PCNA stained sections. Carnoy fixation did not improve results over those fixed with formalin. S-flow and S-LI predicted relapse-free survival, but PCNA indices did not. We conclude that PC10 and 19A2 immunostaining of formalin or Carnoy fixed archival breast cancer tissue correlated with reference measures of proliferation only in cases of short storage periods. Although statistically significant, levels of correlation were too low to use PCNA indices for prognosis.

High proliferative rates demonstrated by bromodeoxyuridine labeling index in breast carcinomas with p53 overexpression

The protein p53 is a product of a suppressor oncogene. Mutations occurring in 13-15% of breast carcinomas are associated with p53 stainability within nuclei and progression of the tumor. We determined the extent to which p53 abnormality was associated with proliferation by measuring p53 immunohistochemically with a polyclonal antibody and monoclonal PAb1801 in invasive carcinomas of known S-phase fraction (SPF) assessed histologically by bromodeoxyuridine incorporation. Results with the two antibodies always agreed. One of 20 low, 2/18 midrange, and 9/17 high SPF carcinomas were positive for p53. P53 positivity was also related to other indicators of aggressiveness including size of primary tumor, nuclear and nucleolar size, and estrogen and progesterone receptor content, but relationships between p53 and vascular invasion and lymph node metastasis were not found. We conclude that nuclear p53 accumulation is more closely related to proliferation than to invasion and metastasis, and that it identifies some but not all breast carcinomas with high proliferative indices.

CT changes associated with normal aging of the human brain

CT was used to measure changes in cerebral gray and white matter tissue densities associated with normal aging, using a cross-sectional design, in order to provide normative data for comparisons with abnormal aging such as dementias of Alzheimer's and vascular types. Cerebral compartmental densities were measured using plain CT, and their perfusion values were recorded during stable xenon inhalation (CT-CBF), among 81 neurologically and cognitively normal volunteers of different ages. Results led to the conclusion that cortical gray matter tissue densities progressively decline (polio-araiosis) after age 60. Cortical polio-araiosis is coupled with regional hypoperfusion but not with cortical atrophy. It is speculated that the cortical hypodensity identified by CT imaging parallels declines in cortical synaptic density, as reported from autopsy studies using anti-synaptophysin staining of cerebral cortex obtained from normal people above and below age 60. The coupling of cortical hypoperfusion with polio-araiosis is believed to reflect age-related reductions of cortical metabolic demands as reported by PET. During normal aging leuko-araiosis correlates directly with cortical atrophy, suggesting that anterograde axonal degeneration resulting from cortical neuronal dearborization play a role in its causation.

Vascular imaging in children

Advances in technology have brought about the wide variety of imaging modalities that are presently available. The development of digital subtraction angiography, computed tomography, ultrasonography, and magnetic resonance imaging have had a particular impact on vascular imaging. These modalities, general principles of study selection, and imaging approaches for specific entities are reviewed.

Prospective studies of cerebral perfusion and cognitive testing among elderly normal volunteers and patients with ischemic vascular dementia and Alzheimer's disease

To compare longitudinal changes of cerebral perfusion (CBF) and cognitive status in two common forms of dementia in the elderly, 42 patients with ischemic vascular dementia (IVD), 44 patients with dementia of the Alzheimer type (DAT), and 120 elderly normal volunteers were evaluated prospectively over a mean interval of 3.35 years. Subjects were at least age sixty, (mean age 71.1). Mean bihemispheric cerebral blood flow and cognitive test scores of control subjects were significantly higher than those of both demented groups at entry and remained so. After adjustment for initial CBF, course over time was similar for all groups. Group variability was similar for CBF but not for cognition. Both IVD and DAT patients were more variable than controls but similar to each other. Throughout, DAT patients showed greater cognitive impairments than IVD patients. Cognitive impairments stabilized among IVD patients treated by control of risk factors, antiplatelet or anticoagulant therapy but declined progressively among DAT patients.

Prenatal cocaine treatment reduces haloperidol-induced catalepsy on postnatal day 10

This study examined the influence of prenatal cocaine on subsequent cataleptic responses to the dopamine (DA) receptor antagonist haloperidol. Pregnant Sprague-Dawley rats were given daily injections of 40 mg/kg cocaine HCl SC from gestational day 8 to 20. Control animals were either uninjected and fed ad lib or saline-injected and pair-fed to the cocaine dams. On postnatal day (PD) 1, litters were culled to eight (sex-balanced if possible) and fostered to surrogate mothers. On PD 10 and PD 15, one male and one female from each litter were injected SC with 1 mg/kg haloperidol or vehicle. Each pup was tested for catalepsy 1 h later by placing its forepaws on an elevated, horizontally oriented dowel rod and recording the latency to remove at least one paw from the dowel. On PD 10 but not PD 15, haloperidol administration produced significantly less catalepsy in the cocaine-exposed subjects than in the untreated controls. No other group differences were observed. These results suggest that prenatal cocaine may alter either the DA system or any of several other neurotransmitters known to influence neuroleptic-induced catalepsy.

Problems encountered with longitudinal neurological, psychometric and cerebral CT imaging among stroke data bank patients with dementia

41 patients (30 men, 11 women, mean age 65.3 +/- 9.7 years) with probable ischemic vascular dementia diagnosed according to stated clinical criteria at least 3 months after hospital discharge and among a few nonhospitalized subjects with thorough clinical, neurovascular and neuroimaging workup have been followed for the past 7 years with serial measures of neurological and cognitive status and cerebral blood flow using stable xenon-enhanced CT. Cognitive impairments correlated with cerebral ischemia rather than CT measurements of infarcted brain volume. A minimum of one follow-up was required and follow-up intervals ranged from 4 months to 6.6 years (mean 3.4 +/- 1.6 years). 9 patients (22.0%) were lost to follow-up, 4.9% died, 9.8% became incapacitated by additional strokes, 2.4% by cancer and 4.9% moved away. Cross-sequential designs adjust for problems of attrition. Mortality rates of 1.4%/year during 1986-1993 are significantly lower than 2.0%/year between 1983 and 1986. Declines in mortality are attributed to control of risk factors and antiplatelet treatment of atherosclerotic cerebral vascular disease and anticoagulant treatment of patients with cardiogenic embolism.

Magnetic resonance imaging of airway obstruction resulting from vascular anomalies

Accurate diagnosis is important in the evaluation of airway disorders of infants and children. Today, multiple imaging techniques are available to evaluate the pediatric airway. We performed magnetic resonance (MR) imaging of the airway in 16 infants and children with symptoms of airway obstruction. Fourteen of 16 patients symptoms were related to compression of the airway by vascular structure. MR imaging was useful in the diagnosis and management of these patients without the need for more invasive procedures.

Diaschisis

Following acute, localized lesions of the central nervous system, arising from any cause, there are immediate depressions of neuronal synaptic functions in other areas of the central nervous system remote from the lesion. These remote effects result from deafferentation, a phenomenon known as "diaschisis". After an interval of time, which will vary directly with the severity of the lesion, functional recovery occurs due to synaptic reactivation of neurones. This is favourably influenced by rehabilitation. Diaschisis most commonly manifests itself by such neurological signs as impaired consciousness or cognitive impairments including dementia, dyspraxias, dystaxias, dysphasias, incoordination and sensory neglect. The nature of diaschisis has been demonstrated by widespread depressions of local cerebral blood flow and metabolism extending far beyond the anatomical lesion. Recovery of function is associated with recovery of local perfusion and metabolism.

Cell kinetic classification of tumors of the nervous system by DNA precursor labeling in vitro

We studied 142 excisional or needle biopsy specimens of nervous system tumors with tritiated thymidine or 5'-bromodeoxyuridine (BrdUrd). Either precursor gave similar results. A labeling index (LI), expressed as a percentage and representing the S-phase fraction, was measured by a microscopic count from stained sections. The in vitro method ranked mean and median LIs of different neoplasms similarly to reported results from the in vivo administration of BrdUrd and reflected clinical aggressiveness of various tumor types. Gliosis, myxopapillary ependymomas, benign meningiomas, neurilemmomas, and pituitary adenomas consistently showed LIs less than 1%. The LI of a cerebellar Lhermitte-Duclos gangliocytoma was zero, indicating the virtual absence of proliferation. Mean LIs and standard deviations of other tumors were as follows: anaplastic astrocytomas, 3.07% +/- 2.98%; glioblastoma multiforme, 6.15% +/- 5.61%; non-Hodgkin's lymphoma, 12% +/- 9.5%; and metastatic neoplasms, 15% +/- 8.5%. The survival rate of patients with astrocytic tumors was inversely proportional to the LI. We conclude that the in vitro method is a practical alternative to in vivo BrdUrd administration for measurement of S-phase cells in tumors of the nervous system that gives prognostically useful information. Combination of BrdUrd LI with growth fraction measurement by monoclonal antibodies could offer new insights into brain tumor cell kinetics.

Relationship between the ossification center and cartilaginous anlage in the normal hindfoot in children: study with MR imaging

OBJECTIVE

Although many reports have documented when ossification centers can first be visualized on radiographs, few studies have evaluated the position of the ossification center within its cartilaginous anlage. In the skeletally immature child, the ossification centers of the tarsals are used to evaluate the positions of the tarsals and their interrelationships. It is convenient to assume that tarsal ossification begins in the center of its cartilaginous anlage and proceeds in a radial fashion; however, this may not be the case. Accordingly, we used MR imaging to evaluate the location of the ossification centers of the tarsals within their cartilaginous anlage in the mid and hindfoot in children.

MATERIALS AND METHODS

MR studies of 69 feet in 40 children, 3 months to 7 years old (mean, 2.5 years), were reviewed retrospectively. The location of the ossification center within its cartilaginous anlage and the percentage of ossification of the cartilaginous anlagen of the talus, calcaneus, cuboid bone, and navicular bone were determined from coronal and sagittal images. In the talus, the difference between the orientation of the long axis of its ossification center and the long axis of its cartilaginous anlage was measured on coronal and sagittal images.

RESULTS

Early talar ossification was centered on the neck of the talus; the proximal aspect of the bone ossified last. The long axis of the talar ossification center and the long axis of its cartilaginous anlage differed in orientation. Early calcaneal ossification was centered on the distal two thirds of the cartilaginous anlage of the calcaneus; the proximal aspect and the area of the subtalar joint ossified last. Early navicular ossification was centered on the central or lateral third of the navicular cartilaginous anlage; the medial aspect ossified last. The ossification center of the cuboid bone was in the middle of the cuboidal cartilaginous anlage.

CONCLUSION

Our results show that early ossification in the talus, calcaneus, and navicular bones does not begin in the center of the bones' cartilaginous anlagen. The orientations of the long axis of the talar ossification center and the long mid axis of its cartilaginous anlage are different. Therefore, part of the changes in the alignment of the tarsals seen on radiographs with growth is due to ossification beginning and proceeding eccentrically within the cartilaginous anlage and not to a true change in the alignment of the tarsals. These data provide new information about the normal development of the child's hindfoot and midfoot.