Entire Nasal Cavity Research Articles

Pediatric Epistaxis-Effectiveness of Conservative Management.

Epistaxis is an emergency medical condition that sometimes requires admission to the emergency department. Pediatric epistaxis differs from epistaxis in the older population in terms of etiology, severity, and management. Our objective was to identify the distinctive features of pediatric epistaxis and determine the appropriate management. This was a retrospective study of 231 medical records of children (<18 years old) with epistaxis of a total of 1171 cases in the general population who presented to our medical center's emergency department between 2013 and 2018. Among 231 admissions, 10 children (4.3%) presented more than once. Male patients accounted for the majority of cases (64.5%), and the average age was 9.4 years. Two children were treated with aspirin because of cardiac valve disease. Anterior bleeding was detected in 101 cases (43.7%), whereas posterior origin was observed in 8 cases (3.5%). In 122 cases (52.8%), there was no active bleeding observed. Nose injury was the cause of epistaxis in 24 cases (10.4%), and 16 admissions (6.9%) followed nasal surgical interventions. Nineteen children (8%) had abnormal coagulation tests, and 7 patients (3%) received blood transfusions. Chemical cauterization was performed in 89 cases (39.3%), and anterior packing was needed in only 9 cases (3.9%). Nine children required hospitalization (3.9%), and 2 needed surgical intervention to control bleeding. Compared with the adult population, there were significantly fewer cases of active bleeding, recurrent epistaxis, anterior packing, or need for hospitalization in the pediatric population. Epistaxis is significantly less severe in the pediatric population, with only a few cases requiring major intervention. Endoscopic examination of the entire nasal cavity and routine coagulation tests are not mandatory unless there is a history of recurrent epistaxis, known coagulopathy, antiplatelet/anticoagulation therapy, or a suspicion of juvenile idiopathic angiofibroma. We suggest using absorbable packs, which offer advantages over cauterization or nonabsorbable packs.

Endoscopic-Assisted Excision of an Extensive Inverted Papilloma (Krouse Stage IV) through Lateral Rhinotomy Approach: A Case Report

Inverted papilloma is a benign epithelial growth arising from the Schneiderian mucosa with a tendency to grow into the underlying stroma. The etiology remains obscure but its tendency for an association with malignancy makes it an important entity important for the surgeon. We present a case report of an extensive inverted papilloma (Krouse stage IV). The tumour involved entire right side nasal cavity extending to the vestibule, extended to the orbit and also intracranially (though extradural) through the frontal and ethmoid sinuses. This extensive tumour was removed by a combined (lateral rhinotomy plus endoscopic) approach and obviated the need for external approach to frontal sinus as well as extended lateral rhinotomy. Thus, even for extensive tumours using the endoscope as an adjunct aids in complete tumour removal and prevents additional morbidity to the patient.

Low-grade sinonasal non-intestinal-type adenocarcinoma: a rare case report and literature review

Abstract Sinonasal non-intestinal-type adenocarcinoma is a rare but important differential diagnosis in patients presenting with recurrent, unexplained epistaxis. Low-grade types have a more favourable prognosis as opposed to the more aggressive high-grade. Symptoms include nasal obstruction and epistaxis that can last up to 5 years. We report a case of a rare low-grade sinonasal non-intestinal-type adenocarcinoma in a 43-year-old male who is frequently exposed to wood and dust particles. Endoscopy revealed right nasal mass occupying the entire nasal cavity as well as inferior turbinate hypertrophy and mass attached to the nasal septum on computed tomography. Biopsy confirmed the diagnosis and was classified as pT1NX with the presence of mitotic figures, which are more commonly present in the high-grade subtype.

Intraorbital Cavernous Hemangioma: Rare Cause of Exophthalmos

Nasopharyngeal angiofibroma refers to a locally aggressive benign vascular tumor composed of vasogenic and myofibroblastic elements, representing between 0.05% and 0.5% of all head and neck tumors. Here, we report a case of a 21-year-old patient with no particular personal or familial pathological history, who presented with recurrent epistaxis and anterior rhinorrhea and headaches for 1 year. Nasofibroscopy revealed a mass filling the entire left nasal cavity, streaked with blood. A face MRI revealed a highly vascularized and lytic nasopharyngeal tumor infiltrating the deep left lateral facial spaces with the beginning of endocranial infiltration, supplied by the homolateral maxillary artery, initially suggestive of a nasopharyngeal fibroma. Preoperative arteriography showed a voluminous vascular blush at the arterial time to the nasopharyngeal projection with branches arising from the left external and internal carotid arteries and multiple arterial shunts (between the left internal and maxillary carotid arteries), thus contradicting embolization. Early diagnosis is important as it is associated with a high risk of morbidity, but advances in imaging and surgical treatment methods have modified the sites associated with high morbidity risk.

Aggressive Tumor and Challenging Location: A Case Report of Nasopharyngeal Fibroma

Nasopharyngeal angiofibroma refers to a locally aggressive benign vascular tumor composed of vasogenic and myofibroblastic elements, representing between 0.05% and 0.5% of all head and neck tumors. Here, we report a case of a 21-year-old patient with no particular personal or familial pathological history, who presented with recurrent epistaxis and anterior rhinorrhea and headaches for 1 year. Nasofibroscopy revealed a mass filling the entire left nasal cavity, streaked with blood. A face MRI revealed a highly vascularized and lytic nasopharyngeal tumor infiltrating the deep left lateral facial spaces with the beginning of endocranial infiltration, supplied by the homolateral maxillary artery, initially suggestive of a nasopharyngeal fibroma. Preoperative arteriography showed a voluminous vascular blush at the arterial time to the nasopharyngeal projection with branches arising from the left external and internal carotid arteries and multiple arterial shunts (between the left internal and maxillary carotid arteries), thus contradicting embolization. Early diagnosis is important as it is associated with a high risk of morbidity, but advances in imaging and surgical treatment methods have modified the sites associated with high morbidity risk.

Professor LIN Guo-hua's experience in the clinical application of "Dayingxiang"

The paper introduces professor LIN Guo-hua's experience in treatment with acupuncture-moxibustion at "Dayingxiang". Based on the application of Neiyingxiang (internal LI 20), professor LIN defines the entire nasal cavity and its adjacent nasopharynx as "Dayingxiang", of which, "Neiyingxiang" and "Biyandian" (nasopharynx point) are commonly stimulated with acupuncture-moxibustion. "Dayingxiang" may regulate lung qi and promote the circulation of the marrow sea in treatment of the disorders of lung system and the marrow. Fire needling with twirling or burning-scallion technique is predominated in manipulation. "Neiyingxiang" is stimulated for the shallow-located disorders, while, "Biyandian" is for the deep-located ones. These two points are optioned alternatively or in combination to enhance the therapeutic effect.

Primary Nasal Mucosal Melanoma: A Case Report

Nasal mucocal melanoma is a rare and aggressive neoplasm. In most cases, it arises in the lateral wall of the nasal cavity. As it shows nonspecific clinical symptoms and risk factors, anterior nasofibroscopy and imaging plays a crucial role in the diagnosis. The final diagnosis is based on histological and immunohistochemical findings. The wide surgical excision is the mainstay of the treatment and the adjuvant radiotherapy is often used to prevent local recurrence and metastasis. We report a case of a 61 years old female patient with obstruction and epsistaxis. The first facial magnetic resonance imaging was suggestive of an inverted papilloma misleading the diagnosis. The patient had undergone nasal endoscopy with a biopsy. The histological and immunohistochemical were consistent with the diagnosis of a mucosal melanoma. A facial computed tomography revealed a solid mass filling the entire right nasal cavity with extension to the homolateral ethmoidal cells and the maxillary sinus and erosion of the middle and lower turbinates and the nasal septum. A second facial magnetic resonance imaging showed a neoformation of the right nasal cavity. The lesion was initially removed using and endonasal endoscopic approach. Local recurrence occurred one month later, which leaded to perform a lateral rhinotomy approach. The histopathological aspect was consistent with the diagnosis of malignant melanoma and the patient received a postoperative 3D radiation therapy. The diagnosis is based on histological and IHC studies. Wide surgical excision with negative margins is the cornerstone of any treatment regimen for sinonasal mucosal melanoma followed by adjuvant radiotherapy even if there is no clear consensus. In spite of a well conducted treatment, the melanoma of the nasal cavity remains an aggressive tumor with a non-negligent risk of local recurrence, with a poor prognosis and a survival rate not exceeding 35% after 5 years.

Concha bullosa mucocele disguising as a nasal tumor in an epistaxis patient: A case report

Concha bullosa is the most common anatomical variant of middle turbinate in both children and adults. When the natural drainage of concha bullosa is obstructed, it leads to the formation of mucocele. It is confusing with nasal tumor when the entire nasal cavity gets occupied. Concha bullosa mucocele and profuse epistaxis is rarely found in the same patient. Both pathologies require appropriate management for the early recovery of the patient and prevent severe complications like concha bullosa mucopyocele from concha bullosa mucocele and hypovolemic shock from profuse epistaxis. We present a 74-year-old female who presented with profuse epistaxis from the left nasal cavity due to concha bullosa mucocele filling the right nasal cavity and pushing nasal septum towards left side which was confused with nasal tumor.

Juvenile nasopharyngeal angiofibroma tumor – Diagnosis and management in our tertiary hospital

Juvenile nasopharyngeal angiofibroma (JNA) is a rare benign tumor described by slow progression, vigorous growth, high vascularization, and increased recurrence rate. The aim of this article is to describe a case of JNA from our tertiary hospital and discuss the diagnosis and management in our current practice. A 16-year-old male patient presented with bleeding from the left nasal cavity. On examination, there was a non-pulsatile ovoid like mass occluding the entire left nasal cavity which was able to probe medially, superiorly, and laterally except inferiorly and on probing and it resulted in minimal bleed. Cold spatula test revealed decreased fogging on the left side. Contrast-enhanced computed tomography scan of the paranasal sinuses and nose showed the presence of a large ill-defined heterogeneously enhancing soft-tissue density mass lesion with its epicenter in posterior part of the left nasal cavity and left pterygopalatine fossa and was extending into the left orbit and left cavernous sinus. Complete embolization of the left nasopharyngeal vascular mass was done preoperatively. Two days post-embolization, surgical excision of JNA under general anesthesia was done. The approach was done through sublabial incision. This classic case of JNA was operated endoscopically because of its benefits over the conventional methods.

Expect the unexpected – sinonasal papillary intestinal adenocarcinoma – A case report

Intestinal-type adenocarcinoma (ITAC) is the second most frequent sinonasal adenocarcinoma. High incidence of these tumors was seen among workers with occupational wood dust exposure, particularly of hardwood dusts. Furthermore, ITACs associated with dust exposure were diagnosed mostly in men (85–95%) and predominantly in the ethmoid sinus. This contrasts with sporadic ITACs that are more frequent in women and often arise in the maxillary antrum. ITAC had striking histomorphologic and immunophenotypic similarities with colorectal adenocarcinomas, but on the level of molecular pathologic mechanisms, these tumors have their own specific features different from gastrointestinal tumors. A 58-year-old female came with the chief complaints of difficulty in breathing and left-sided nasal obstruction for the past 1 month. On local examination, nasal septum was deviated to the right side on visualizing the left nasal cavity showed a polypoidal growth occupying the entire nasal cavity. Paranasal sinuses with contrast computed tomography (CT) showed a chronic granulomatous lesion in the left nasal cavity with surrounding inflammatory changes involving the ipsilateral sinuses. This patient was planned for functional endoscopic sinus surgery and specimen was sent for histopathological diagnosis. Contradictory to CT scan result, on gross and histopathology, the lesion was diagnosed to be intestinal type of sinonasal adenocarcinoma.

Solitary Fibrous tumor of Nasal cavity: A case report and review of literature.

Introduction and importanceSolitary fibrous tumors (SFTs) involving the nasal cavity are extremely rare with few cases reported in the literature.Case presentationWe present a case of SFT in a 90 year-old male complaining of a slow-growing mass prolapsing through left nostril. Nasal endoscopy and imaging exams revealed a mass occupying the entire left nasal cavity, pushing the nasal septum to the opposite side and extending up to the nasopharynx. Biopsy specimen examination reported sarcoma. The patient underwent complete surgical resection of the mass through left para-latero-nasal approach. Immuno-histochemical analyses confirmed the diagnosis of SFT. The patient has remained free of tumor 2 years after surgery.Clinical discussionClinical and imaging features of SFTs of nasal cavity are not specific. A broad of differential diagnosis is associated with histopathologic features of SFTs. Therefore, immuno-histochemical analyses are crucial to confirm the diagnosis. Complete resection of the mass with clear margins is mandatory to minimize local recurrence.ConclusionSFTs of nasal cavity are very rare neoplasms which continue to pose challenges to practitioner. Pathological examination and mainly immunohistochemical studies are important to establish the diagnosis. Complete resection of the tumor is the key for good outcome.

Rare Schwannomas of Head and Neck and Review of Literature.

Benign schwannoma is a slow growing encapsulated tumor arising from the sheath of Schwann, The majority had extra-cranial localization. We report in this review three cases of a rare extra cranial localization of benign schwannoma in the trachea, frontal sinus and intraparotid facial nerve. The first case diagnosed in a 10-years-old boy, presented with a painless, slow growing mass evolving for three years in the left parotidic region, total conservative parotidectomy was done. The second case concerned a 38-years-old, was admitted to the emergency department with acute inspiratory dyspnea, endoscopic exploration revealed a polylobed tracheal tumor, complete tumor excision was done endoscopically. The third case was about a 33years old patient, presented a gradually enlarging frontal swelling associated with headache and left nasal obstruction, the endoscopic examination revealed a gray pinkish, smooth and firm soft tissue mass occupying the entire left nasal cavity, CT scan and MRI were requested to assess the characteristics and extent of the tumor, The surgical intervention combined two approaches: trans facial through a mid-frontal incision, and endonasal one. Histopathological examination confirmed the diagnosis of benign schwannoma in all these cases.

A rare metastatic follicular thyroid carcinoma masquerading as primary sinonasal carcinoma presentation with unusual orbit, skull base and brain metastases

Tumour involving the sinonasal tract account for only 1% of all malignancies. The large majority of tumours affecting sinonasal tract are mainly primary neoplasm or from direct extension of adjacent region; metastatic tumour affecting sinonasal tract are extremely rare. Most of the metastases are originate from carcinoma inferior to the clavicle, including renal, breast, lung, and prostate. The incidence of metastases to sphenoid sinus are even rare. We describe a rare case of metastases of FTC to sinonasal tract, mimicking primary sinonasal carcinoma presentation, with unusual orbit, skull base and brain metastases.A 66-year-old lady with history of subtotal thyroidectomy for FTC presented with epistaxis associated with proptosis of left eye. Nasal endoscopy revealed vascularised mass occupying the entire left nasal cavity. Endoscopic transnasal biopsy was performed which showed metastatic FTC with positive immunochemical staining for thyroglobulin, and thyroid transcription factor-1. Computed tomography angiography demostrated a large vascular tumour involving the left maxillary sinus, bilateral ethmoid and sphenoid sinuses. The mass causing erosion of nasal septum and pterygoid plates and left temporal bone, with extension to left orbit, infratemporal fossa and intracranial. Patient received thyroid stimulating hormone suppression therapy followed by radio-iodine ablation.As surprisingly rare, the purpose of our study is to raise the awareness regarding the possibility of FTC metastatizing to sinonasal tract, orbit, skull base and intracranial. The completion thyroidectomy intervention is crucial for better future prognosis. Thyroid carcinoma should be considered in differential diagnosis of epistaxis and potential primary neoplasm in patient with orbital metastases.

Huge B-Cell Lymphoma of the Maxillary Sinus: Case Report and Review of the Litterature

Primary non-Hodgkin’s lymphoma (NHL) of Paranasal sinus is a rare entity with special characteristics; their locations in the air spaces of the face coming in second row. The prognosis depends on tumor stage and extension into the paranasal sinuses We related the case of a primitive NHL located in the maxillary sinus in a patient of 50 years, invading the entire homolateral nasal cavity. The histopathologic interpretation was B cell lymphoma; the patient received 5 adjuvant chemotherapy treatments according to the CHOP protocol, followed by locoregional external radiotherapy and the evolution was favorable after eighteen months follow-up

A rare cause of bilateral exophthalmos: about one case with a sphenoid mucocele

Background: Mucocele is a benign cystic pseudo-tumor that develops within the sinus cavities. The most frequent locations are frontal and frontoethmoidal. The sphenoidal forms are rare. We report a case of sphenoidal mucocele revealed by bilateral exophthalmos. Methods and results: We report the case of a 14 year old male patient, without any particular pathological history, referred by his ophthalmologist for bilateral nasal obstruction, bilateral exophthalmos and visual acuity decrease evolving since one year. The ENT examination found a large, renitrant mass, filling the entire right nasal cavity. This mass pushed the nasal septum to the left. The CT scan showed a large sphenoidal, hypodense mass evoking a mucocele. The patient underwent endonasal marsupialization by endoscopic guidance. Conclusions: Sphenoidal mucocele is a rare cause of bilateral exophthalmos. The diagnosis can be misplaced when the signs are overt extra-sinus. Hence the interest of CT in order to eliminate other differential dignostics.

CYSTIC ADENOID CARCINOMA OF LARGE EXTENSION IN THE MAXILLA: A CASE REPORT

Cystic adenoid carcinoma (CAC) is a slow-growing, malignant gland neoplasm, with predominance in the palate region. A 54-year-old female patient presented with an extensive ulcerated lesion, with bleeding, painless, endophytic growth, affecting the hard and soft palate, with evolution of 8 months. Image examination showed a hypodense lesion with indefinite limits, involving the palate, the entire nasal cavity, and the left maxillary sinus. After facial clinical and imaging findings were reviewed, incisional biopsy was performed in the peripheral regions of the lesion, and the patient was instructed to suspend the use of the total prosthesis. The histologic examination concluded CAC diagnosis. Because it was a malignant lesion, the patient was referred to a state referral center to continue the treatment. The role of the dentist is of paramount importance in diagnosing and conducting the primary treatment of lesions in the maxillofacial region. Cystic adenoid carcinoma (CAC) is a slow-growing, malignant gland neoplasm, with predominance in the palate region. A 54-year-old female patient presented with an extensive ulcerated lesion, with bleeding, painless, endophytic growth, affecting the hard and soft palate, with evolution of 8 months. Image examination showed a hypodense lesion with indefinite limits, involving the palate, the entire nasal cavity, and the left maxillary sinus. After facial clinical and imaging findings were reviewed, incisional biopsy was performed in the peripheral regions of the lesion, and the patient was instructed to suspend the use of the total prosthesis. The histologic examination concluded CAC diagnosis. Because it was a malignant lesion, the patient was referred to a state referral center to continue the treatment. The role of the dentist is of paramount importance in diagnosing and conducting the primary treatment of lesions in the maxillofacial region.

A rare case of inflammatory myofibroblastic tumour in the maxillary sinus: masquerading a malignancy

&lt;p&gt;Aim establishing the diagnosis of inflammatory myofibroblastic tumour is very challenging due to its varied clinical and radiological manifestations. We report a rare presentation of a 5 years old female child with inflammatory myofibroblastic tumour, which was endoscopically resected with postop steroid therapy. Case report, a 5 years old female child presented to ENT OPD with complaints of right nasal obstruction since, 4 months along with recurrent minor episodes of spontaneous bleeds from the right nasal cavity. On examination a huge fleshy reddish polypoidal and pulsatile mass was seen filling the entire right nasal cavity associated with right eye proptosis. MRI with contrast showed expansion of right maxillary sinus bony walls with internal soft tissue leision measuring 41 mm (TRANS) × 36 mm (AP)×31 mm (CC) seen enhancing with contrast. Vascular supply is from maxillary artery. Under anaesthesia right external carotid artery ligation was done followed by removal of mass from right nasal cavity. Histopathological examination was consistent with inflammatory myofibroblastic tumour. On immunohistochemistry spindle cells showed cytoplasmic positivity for SMA. Inflammatory myofibroblastic tumour though a very unusual tumour, should be considered in the differential diagnoses of tumours in the nasal cavity. A vigilant clinical evaluation and extensive imaging along with histopathological examination can guide us to an early diagnosis and proper treatment resulting in better patient satisfaction.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;

Deposition characteristics of a novel intranasal formulation of azelastine hydrochloride plus fluticasone propionate in an anatomic model of the human nasal cavity.

Background: Intranasal antihistamines and steroids should be delivered in a volume and with a technique that allow for optimal drug retention within the entire nasal cavity, maximize local absorption by the nasal mucosa, and, subsequently, increase the potential for the most desirable local availability and therapeutic effect. Objective: This in vitro evaluation simulated nasal medication deposition and evaluated the extent of runoff. MP-AzeFlu, a novel intranasal formulation of azelastine hydrochloride (AZE) plus fluticasone propionate (FP), was compared with sequential sprays of available commercial products with the individual medication components. Methods: A model of a normal adult human nasal cavity was used to visualize deposition of nasal spray products. A single spray of MP-AzeFlu (0.137 mL [137 μg of AZE/50 μg of FP]) or single sequential sprays of AZE nasal spray (0.137 mL [137 μg]) followed by brand name or generic FP nasal spray (0.100 mL [50 μg]) were manually actuated into the model. The interior was coated with a water-sensitive dye that changes to magenta when exposed to aqueous-based formulations. A slight vacuum was applied during spray delivery to simulate sniffing. The results were photographed by using anterior and lateral views. Results: Three replicates of MP-AzeFlu showed no dripping from the front of the nostril or backflow from the nasal cavity. However, three replicates of AZE nasal spray, followed by a brand name or generic FP nasal spray, showed significant dripping from the front of the nostril and backflow from the nasal cavity. Conclusion: A single spray of MP-AzeFlu resulted in no runoff compared with sequential dosing of the two other therapeutic products. Product runoff is likely due to the volume exceeding the capacity of the nasal cavity model. Furthermore, the common clinical dosing regimen of two sprays per nostril of each of the individual components would promote even greater increased undesirable flooding and leakage.

Giant schwannoma of the left maxillary sinus - a rare case report

Abstract BACKGROUND. Polyps, cysts and mucocele are the commonest sinonasal tumors present unilaterally, as well as invasive tumors, such as inverted papillomas and squamous cell carcinomas. On the contrary, Schwannomas are rare lesions found in this area. MATERIAL AND METHODS. We present a case of a 48-year-old female who presented with a 2-year progressive history of left nasal obstruction, cranio-facial fullness sensation and pain, with intermittent epistaxis. The CT scan of the nose and paranasal sinuses showed complete opacification of the entire left nasal cavity and maxillary sinus, causing a deviated nasal septum to the right side. RESULTS. The tumor was completely excised endoscopically without any complication. Histopathology was consistent with that of a schwannoma. CONCLUSION. The diagnosis of sinonasal Schwannomas remains challenging, as it is a rare tumor and sometimes its clinical behaviour and imaging may be misleading. The treatment of choice for paranasal sinus schwannoma is complete excision of the tumor with good prognosis.

The growing concern of radiation dose in paediatric dental and maxillofacial CBCT: an easy guide for daily practice.

To provide an indication-based and scanner-specific radiation dose and risk guide for paediatric patients undergoing dental and maxillofacial cone beam computed tomography (CBCT) examinations. Five commercially available scanners were simulated in EGSnrc Monte Carlo (MC) code. Dedicated, in-house built, head and neck voxel models, each consisting of 22 segmented organs, were used in the study. Organ doses and life attributable risk (LAR) for cancer incidence were assessed for males and females, aged 5 to 14years old, for every clinically available protocol: central upper and lower incisors, upper and lower premolars, upper and lower jaws, cleft palate, temporal bone, sinus, dentomaxillofacial complex, and face and skull imaging. Dose results were normalised to the x-ray tube load (mAs) and logarithmic curves were fit to organ dose and risk versus age data. Females demonstrated higher LAR values in all cases. A well-established dose decreasing pattern with increasing age-at-exposure was observed. Central upper incisor protocols were those with the lowest risk, contrary to skull protocols which provided the highest LAR values. Salivary glands and oral mucosa were the highest irradiated organs in all cases, followed by extrathoracic tissue (ET) in protocols where the entire nasal cavity was inside the primary field. The dose to thyroid was considerably high for younger patients. This work provides an extensive dose assessment guide for 5 dental CBCTs, enabling detailed dose assessment for every paediatric patient. • Radiation dose concerns due to the growing use of paediatric dental and maxillofacial CBCT underline the need for justification that should in part be based on radiation exposure in radiology. • Patient-specific dose calculations based on Monte Carlo simulations and head-neck paediatric voxel models overcome the limitations of conventional thermoluminescent dosimeter (TLD) dosimetry and provide proper guidance for justification of CBCT exposures. • Monte Carlo simulations with head-neck models reveal an organ dose and radiation risk decreasing pattern with increasing age at exposure, and with decreasing size of the scanning volume of interest (field of view).