Identification of Juxtaforaminal Fat Pads of the Second Division of the Trigeminal Pathway on MRI and CT

Abstract

385erineural spread can carry malignancy beyond a planned area of surgical resection or targeted region for radiation therapy. Detection or exclusion of perineural spread is therefore a significant goal in the evaluation of a patient with head and neck cancer. Imaging is the primary method for detection of this phenomenon. The second division of the trigeminal nerve is an important potential pathway. Tumor can reach the pterygopalatine fossa and then extend intracranially via the foramen rotundum. Such spread can enlarge the Pictorial Essay P IOF SOF FR IC IF GPN PPF PPG FO FR IF Zygoma IN PPC 3 2 1 Fig. 1.-Drawing shows pathway of second (maxillary) division of trigeminal nerve. 1 = first (ophthalmic) division, 2 = second (maxillary) division, 3 = third (mandibular) division, FO = foramen ovale, FR = foramen rotundum, IN = infraorbital nerve, PPG = pterygopalatine ganglion, PPF = pterygopalatine fossa, GPN = greater palatine nerve, PPC = greater palatine nerve entering pterygopalatine canal, IF = infraorbital foramen.Fig. 2.-Drawing shows anterior view of orbit and infraorbital canal and foramen. IOF = inferior orbital fissure, SOF = superior orbital fissure, FR = foramen rotundum, IC = infraorbital canal, IF = infraorbital foramen. (Modified with permission from [5])

Diseminación perineural en tumores de cabeza y cuello

“…El realce periférico se debe al plexo venoso perineural y se observa frecuentemente en los segmentos foraminales de las tres ramas del trigémino, en el ganglio geniculado, en el NPSM y en la parte proximal del segmento laberíntico del nervio facial 35,54 . -Borramiento u obliteración de los paquetes grasos yuxtaforaminales 55 , como consecuencia del crecimiento del tumor y del componente inflamatorio asociado ( fig. 5).…”

Trigeminal neuralgia and facial nerve paralysis

“…The motor root divides into two major branches, the masticator nerve supplying motor innervation to the temporal, masseter, and pterygoid muscles, and the mylohyoid branch that supplies the mylohyoid and the anterior belly of the digastric muscle [3,4,7,8].…”

“…The most common lesion affecting the peripheral trigeminal nerve is perineural spread of head and neck malignancies [4,[8][9][10]. This occurs more commonly along the second division or maxillary division of the trigeminal nerve due to its extensive branching network, but may also occur along V1 and V3.…”

“…MRI is the imaging modality of choice to detect perineural spread. T1W images are particularly well suited to depict perineural spread as they easily demonstrate obliteration of the juxtaforaminal fat pads, neural thickening and foraminal enlargement [8]. Fat suppressed gadolinium enhanced T1W images are ideal to demonstrate the extent of pathologic neural enhancement.…”

Cone-beam CT (CB Throne) Applied to Dentomaxillofacial Region

“…Conventional CT imaging is used as a diagnostic tool not only in maxillofacial region examinations 1,7) , but also in the preoperative evaluation of dental implants 1) . Recently, this has led to the development of various image-guided applications.…”