Sensitivity and specificity of magnetic resonance imaging and computed tomography for the determination of the developmental state of cranial sutures and synchondroses in the dog

Abstract

Background During skull ontogenesis, growth centers in the skull base and calvarial bones allow gradual expansion of the cranial vault. Premature growth termination of cranial base synchondroses and/or calvarial sutures can result in devastating skull dysmorphologies. There is evidence to believe that a premature closure in one or more cranial growth centers contribute to the brachycephalic skull morphology in dogs. To provide a proof of concept for the non-invasive investigation of ontogenetic changes in cranial sutures and synchondroses in living dogs, we compared magnet resonance imaging (MRI) and computed tomography (CT) with histologic findings. Our aim was to determine the in vitro sensitivity and specificity for conventional clinical imaging methods in the assessment of cranial suture closure and synchondroses ossification in dogs. Results The evaluation of cranial base synchondroses in MRI had a sensitivity of up to 93.1% and a specificity of 72.7% dependent on the observer. The evaluation of cranial base synchondroses in CT had a sensitivity of 92.2% and a specificity of 86.4%. Suture assessment on MRI suture assessment had a sensitivity of 82.1% dependent on the observer and a specificity of 19.3%. CT suture assessment had a sensitivity of 85.1% and a specificity of 40.4% in dependence of the observer. Conclusion Conventional cross-sectional imaging techniques (MRI and CT) allow reliable assessment of the open or closed state of synchondroses within the cranial base. In contrast CT and MRI are not suitable for a reliable assessment of the cranial sutures in dogs.

Canine calvarial subperiosteal hematomas are fluid to soft tissue attenuating mass‐like lesions with smoothly marginated peripheral mineralization on CT

“…Periosteal anatomy is not well described in veterinary medicine in young animals. However, the reported age for fusion of the calvarial sutures varies from 12 months to 4 years 12,17,18 . All of the dogs in this study were young with the oldest being 6 months of age, which is well below the age of suture closure for these references.…”

“…In this dog, the lesion, measuring 6.4 cm × 3.5 cm × 1.8 cm (length × width × height), was associated with the left parietal bone bordered by the region of the frontoparietal suture, squamous suture, sagittal suture, occipitoparietal suture, and parietointerparietal suture (Figure 3). 11,12 Four out of four cases had discontinuity of the mineralized outer shell and none showed disruption of the external table of the skull (Figure 4). The mineralized outer shell of each of these lesions tapered at the periphery becoming continuous with the skull and, in the case of dog 1, with the diffusely thickened periosteum.…”

“…However, the reported age for fusion of the calvarial sutures varies from 12 months to 4 years. 12,17,18 All of the dogs in this study were young with the oldest being 6 months of age, which is well below the age of suture closure for these references. There is the possibility that this suture closed early in these dogs which led to the lesion being able to cross midline.…”

“…Of the three cases (dogs 1, 2, and 3) that were given contrast, dog 1 had a mix of mildly contrast enhancing portions (15‐38 HU precontrast, 64 HU postcontrast) and non‐contrast enhancing portions while the other two cases (dogs 2 and 3) had no contrast enhancement centrally. In three dogs (dog 2, 3, and 4), the lesion was midline along the frontal bones between the region of the frontonasal suture and frontoparietal suture but crossing the interfrontal suture (Figure 2) 11,12 measuring 6.5 cm × 5 cm × 1.7 cm, 4.2 cm × 4 cm × 1.8 cm, and 4.5 cm × 3.1 cm × 0.5 cm, respectively (length × width × height). This lesion was more extensive in another dog (dog 1) where there was diffuse dorsal periosteal thickening of the frontal bones, parietal bones and occipital bone from the frontal sinuses to the occipital protuberance.…”

“…This lesion was more extensive in another dog (dog 1) where there was diffuse dorsal periosteal thickening of the frontal bones, parietal bones and occipital bone from the frontal sinuses to the occipital protuberance. In this dog, the lesion, measuring 6.4 cm × 3.5 cm × 1.8 cm (length × width × height), was associated with the left parietal bone bordered by the region of the frontoparietal suture, squamous suture, sagittal suture, occipitoparietal suture, and parietointerparietal suture (Figure 3) 11,12. Four out of four cases had discontinuity of the mineralized outer shell and none showed disruption of the external table of the skull(Figure 4).…”