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Biomedical subjects

A D King

Publications and source records attributed to A D King.

At least 37 records · Page 2Linked to original sources

Staging papillary carcinoma of the thyroid: magnetic resonance imaging vs ultrasound of the neck.

AIM: To evaluate the role of magnetic resonance imaging (MRI) for staging local disease and lymph node metastases in papillary carcinoma of the thyroid by comparing MRI with ultrasound (US) of the neck. MATERIALS AND METHODS: Fourteen patients with papillary carcinoma underwent MRI and US. The images were prospectively reviewed for (1) identification of the primary lesion; (2) presence of multifocal thyroid disease; (3) extracapsular extension; (4) invasion into the trachea, oesophagus and major vessels; and (5) presence of lymph node metastases. Correlation was made with the surgical findings. RESULTS: The site of the primary lesion was correctly identified by US in 14 of 14 (100%) and by MRI in 13 of 14 (93%) of patients. Multifocal thyroid tumour was correctly identified by US in two of two patients (100%) and by MRI in zero of two (0%). Extracapsular extension (n = 9), oesophageal invasion (n = 1) and tracheal invasion (n = 2) were identified by MRI in seven, zero, and one, and by US in six, zero and zero patients, respectively. Invasion of the major vessels was not seen. Metastatic cervical nodes were present in 19 nodal groups in 10 patients involving the internal jugular chain (n = 10), posterior triangle (n = 4) supraclavicular fossa (n = 1) and central group (n = 4). Both MRI and US failed to identify metastatic nodes in the central group but correctly identified 14 of the 15 nodal groups outside the central group. CONCLUSION: Ultrasound should be used as the first line of investigation for detecting the primary lesion, multifocal disease and cervical lymphadenopathy. In cases where the primary tumour is not surrounded by normal thyroid tissue MR imaging should be added to assess extracapsular spread, especially into the trachea.

Adolescent↗

Sonographic appearances of preauricular sinus.

AIM: Preauricular sinuses are a common congenital abnormality. This study was performed to determine their sonographic features. MATERIALS AND METHODS: Fifteen preauricular sinuses (in 13 patients) were examined using a 5-10 MHz transducer to evaluate the nature of the sinus. Surgical correlation was obtained in 11 cases. RESULTS: Sonography detected the sinus in all cases. The maximum width of the sinus tract was 3 mm; it showed a branching pattern in four (27%) patients. Nine sinuses (60%) led to a cystic component, and the remaining six (40%) showed terminal ramification. Gas was identified within the sinus in nine (60%) cases. In the patients that underwent surgery, the diagnosis and the relationship of the sinus/ cystic component to the superficial temporal artery (STA), anterior crus of the helix and the tragus was confirmed and correlated well with the sonographic findings. However, the branching pattern of the sinus tract was difficult to confirm. CONCLUSION: Sonography readily detects preauricular sinuses and demonstrates their relationship to the STA, anterior crus of the helix, and the tragus, and can therefore be helpful in pre-operative assessment. Ahuja, A. T. (2000). Clinical Radiology 55, 528-532.

Adolescent↗

Radiation induced sarcomas of the head and neck following radiotherapy for nasopharyngeal carcinoma.

AIM: To report the radiological findings of radiation induced sarcomas (RIS) in the head and neck following radiotherapy for nasopharyngeal carcinoma. MATERIALS AND METHODS: The clinical notes and radiological studies (MR n = 3, CT n = 4) of four patients were reviewed retrospectively. RESULTS: RIS developed 5 to 10 years following radiotherapy. Two patients had tumours arising from the alveolar process of the maxilla, one from the nasal cavity, and one patient had a tumour at two sites, involving the external auditory canal and the uvula. Three of the four patients had large tumours at diagnosis with a 3.5-6 cm predominately homogeneous soft tissue mass, complete destruction of bone and extensive local invasion. One was small and localized to the nasal turbinate. Radiation osteitis was identified in two of the four (50%) patients. CONCLUSION: The site of RIS following radiotherapy for NPC is variable but is invariably within the high dose zone of the radiotherapy. These sarcomas tend to present late with a large soft tissue mass. Radiation osteitis is not a constant feature. As surgery provides the only chance of cure, imaging has an important role in the pre-operative mapping of the extent of tumour. et al.

Adult↗

Sonographic evaluation of thyroglossal duct cysts in children.

BACKGROUND AND AIMS: Thyroglossal duct cysts (TDC) in children have a variable sonographic appearance. Some reports have suggested that TDCs appear on ultrasound as well defined, cystic masses with thin walls and posterior enhancement, whereas others have documented a heterogeneous echopattern within these lesions. In our experience, although TDCs in children have a variable ultrasound appearance, the most common appearance is that of a pseudosolid mass closely related to the hyoid bone. In this study we report on 23 patients with thyroglossal duct cysts and document the ultrasonic patterns. PATIENTS AND METHODS: All patients in whom the diagnosis of TDC was made clinically (by at least two head and neck surgeons) and in whom ultrasound detected a cystic mass related to the hyoid bone, were included in this study. Sonograms of 23 children with TDCs were reviewed. The features evaluated included their location, internal echogenicity, posterior enhancement, the presence of septa, a solid component and a fistulous tract. The echopattern was not correlated with the biopsy results. RESULTS: Three patterns of TDCs were identified: anechoic (13%); pseudosolid (56.5%); and a heterogeneous pattern (30.5%). The majority were midline (82.6%), showed posterior enhancement (56.5%), and had thin walls (82.6%). CONCLUSION: On ultrasound, TDCs in children are not simple cysts but have a complex pattern ranging from a typical anechoic cyst to a pseudosolid appearance (most common).Ahuja, A. T. (2000). Clinical Radiology55, 770-774.

Adolescent↗

Spontaneous necrosis of parathyroid adenoma: biochemical and imaging follow-up for two years.

We report a patient with a biochemically and radiologically confirmed parathyroid adenoma, which underwent spontaneous resolution by necrosis. The patient was followed-up over the subsequent two years during which time the tumour and hypercalcaemia recurred. Sequential radiological and biochemical changes at the time of diagnosis, spontaneous necrosis and recurrence are documented fully.

Adenoma↗

MR imaging of nasal T-cell/natural killer cell lymphoma.

OBJECTIVE: Nasal T-cell/natural killer cell lymphoma is a distinct clinicopathologic entity derived from natural killer cells. The purpose of the study was to describe the MR features of this rare nasal cavity tumor and correlate MR findings with stage of disease. CONCLUSION: Nasal T-cell/natural killer cell lymphoma frequently exhibits diffuse invasion of the nasal cavity with necrosis, midline destruction, and extension into the nasopharynx. These features may be seen in both early- and late-stage disease.

Adult↗

Second branchial cleft cysts: variability of sonographic appearances in adult cases.

BACKGROUND AND PURPOSE: Previous reports have suggested that second branchial cleft cysts (BCCs) appear on sonograms as well-defined, cystic masses with thin walls and posterior enhancement. Previous CT and MR imaging findings, however, have indicated heterogeneity of these masses, and, in our experience, sonography also shows a similar variable appearance. In this communication, we report the cases of 17 patients with second BCCs and document the variability of sonographic patterns. METHODS: The sonograms of 17 adults with second BCCs were reviewed. Only patients with surgical or cytologic evidence of BCCs were included in this study. The features evaluated were the location, internal echogenicity, posterior enhancement, and presence of septa and fistulous tract. RESULTS: Four patterns of second BCCs were identified: anechoic (41%), homogeneously hypoechoic with internal debris (23.5%), pseudosolid (12%), and heterogeneous (23.5%). The majority (70%) showed posterior enhancement. All were situated in their classical location, posterior to the submandibular gland, superficial to the carotid artery and internal jugular vein, and closely related to the medial and anterior margin of the sternomastoid muscle. Fourteen (82%) of the 17 BCCs had imperceptible walls, and all were well defined. For none of the patients was a fistulous tract revealed by sonography; the presence of internal septations was revealed for three patients. CONCLUSION: As previously suggested by CT and MR imaging findings, sonography reinforces that second BCCs in adults are not simple cysts but have a complex sonographic pattern ranging from a typical anechoic to a pseudosolid appearance.

Adolescent↗

Intrathyroidal lymphoepithelial (branchial) cyst: sonographic features of a rare lesion.

Intrathyroidal lymphoepithelial cysts are rare, and only 15 such cases have been reported. Although sonography has been performed in some cases, the findings have not been discussed previously. Despite its rarity, the sonographic appearances of this lesion are similar to those of other commonly encountered congenital cystic lesions in the head and neck, such as thyroglossal duct cysts and second branchial cleft cysts, and this may provide a clue to its diagnosis. We describe the sonographic appearances of intrathyroidal lymphoepithelial cysts.

Biopsy, Needle↗

Middle ear effusions after radiotherapy: correlation with pre-radiotherapy nasopharyngeal tumor patterns.

OBJECTIVE: The purpose of this study was to assess whether pretreatment tumor patterns of nasopharyngeal carcinoma (NPC) can predict the status of the middle ear after radiation treatment. MATERIALS AND METHODS: Pretreatment and follow-up magnetic resonance imaging (MRI) was performed in 32 patients (64 ears) who had radiation therapy for NPC. For the purpose of analysis, the ears were placed into their pre-radiation therapy tumor pattern groups and the presence of middle ear effusion (MEE) with regard to eustachian tube (ET) invasion or displacement was identified. RESULTS: MEEs were present in 31 (48.4%) ears after radiation therapy. All of the MEEs that resolved were in the preradiation therapy groups where tumor invasion of the eustachian tube was present irrespective of the amount of ET displacement. There was, however, no significant difference for resolved MEEs between ears with ET invasion or displacement (p = 0.32 and p = 0.71, respectively, Fisher's exact test). The MEEs occurred with significantly greater frequency in ears with minor ET displacement than in those with major ET displacement (p = 0.013, Fisher's exact test) as well as in previously normal ears compared with other groups (p = 0.008, Mann-Whitney U test). CONCLUSION: A pre-radiation therapy NPC tumor pattern was not found that clearly predicted the outcome of MEE after radiation treatment. The findings, however, suggest that approximately one third of MEEs in patients with invasion of ET or paratubal structures, irrespective of the amount of ET displacement, resolve after therapy. The MEEs that were present in ears with ET displacement and no invasion did not resolve despite reversal of the displacement after treatment, which suggests that ET position plays a less important role than invasion in the resolution of MEE. It is, however, difficult to be certain, because ears with invasion were invariably associated with ET displacement, and the contribution of radiation therapy to the development of MEE further complicates the issue.

Adult↗

Hypoglossal nerve palsy in nasopharyngeal carcinoma.

BACKGROUND: The aim of the study was to use magnetic resonance (MR) imaging to determine the cause of hypoglossal nerve palsy and the sites of injury in patients with nasopharyngeal carcinoma before radiation therapy and during postradiation therapy follow-up. METHODS: The clinical records and MR studies of 21 patients with hypoglossal nerve palsy were retrospectively studied. These 21 patients belonged to a cohort of 387 patients with nasopharyngeal carcinoma (153 with newly diagnosed disease and 234 on postradiation follow-up) who underwent MR imaging in a 2.5-year period. RESULTS: Four patients had hypoglossal nerve palsy at initial diagnosis and all of them had extensive skull base invasion from tumor extending postero-inferiorly to the level of the foramen magnum. The nerve was invaded in the carotid sheath (3), hypoglossal nerve canal (3), and premedullary cistern (1). In 17 patients developing hypoglossal nerve palsy after radiotherapy, only two (12%) had evidence of tumor recurrence. Radiation-induced neuropathy was the probable cause in 14 patients and 1 case was judged indeterminate. MR evidence of fibrosis was demonstrable along the course the nerve in four patients (29%), involving the carotid sheath (4), hypoglossal nerve canal (2), and premedullary cistern (1). No patient had MR evidence of radiation change in the brain stem. Seven patients had a history of a boost dose of radiation to the parapharyngeal region on one or both sides, and nerve palsy occurred on the boosted side in six of them. CONCLUSION: Hypoglossal nerve palsy on presentation was caused by locally advanced nasopharyngeal tumor whereas a palsy arising after radiation therapy was more frequently caused by postradiation damage rather than cancer.

Adenocarcinoma↗

MRI evaluation of multifidus muscles in adolescent idiopathic scoliosis.

BACKGROUND: The role of the multifidus muscles in the initiation and progression of curve in adolescent idiopathic scoliosis is not fully understood and controversy exists as to the side of the abnormality. OBJECTIVE: To evaluate on MRI the multifidus muscles at the apex of the major curve in adolescent idiopathic scoliosis to ascertain if the multifidus muscles on the convex or concave side are abnormal and the relationship to curve severity. MATERIALS AND METHODS: Forty-six patients with adolescent idiopathic scoliosis, separated into two groups, were studied using a 1.5-T MR scanner with the synergy spine coil, employing a modified STIR (short tau inversion recovery) axial sequence obtained at the apex of the major scoliotic curve. RESULTS: No hyperintense signal change was demonstrated in the convex side multifidus muscles in any patient. In group I, 16 of 18 patients with severe or rapidly progressive curve showed increase in signal intensity in the multifidus muscle on the concave side of the apex of the curve. In group II, of the 15 patients with mild curve (Cobb angle 10-30 degrees), 4 had increased signal intensity in the multifidus muscle on the concave side; of the 13 with more severe curve (Cobb angle greater than 30 degrees), 10 had increase in multifidus signal intensity on the concave side. CONCLUSIONS: The concave-side multifidus muscle at the apex of a scoliotic curve was morphologically abnormal. A significant association between abnormal signal change and curve severity was also established.

Adolescent↗

Head and neck cancers associated with Madelung's disease.

BACKGROUND: Madelung's disease is a rare lipodystrophy that presents with multiple fatty masses in the neck, trunk, and upper extremities. The fatty accumulation is considered a benign disease, but compression of the aerodigestive tract may occur in long-standing disease. METHODS: Eight Chinese patients with Madelung's disease were reviewed. All were male, aged 48 to 67 years, with a history of disease ranging from 4 to 20 years. Two of the eight patients developed aerodigestive symptoms and were subsequently found to have head and neck cancers. These two patients are described. RESULTS: The possible mechanism that may account for an increase in malignant tumors of the airway in this group of patients is the synergistic effect of smoking and alcohol abuse as risk factors for both Madelung's disease and malignant tumors of the airway. Currently it is recommended that these patients should have their fatty lesions removed surgically. The removal of fat facilitates examination of the neck for signs of cervical lymphadenopathy in malignant disease. CONCLUSIONS: Patients with Madelung's disease should be followed regularly. The development of aerodigestive symptoms should be fully investigated with endoscopy and imaging. The cause of symptoms should not be attributed to fatty compression until a carcinoma of the upper airway has been excluded.

Alcoholism↗

Palatal lymphoepitheliomas and a review of head and neck lymphoepitheliomas.

AIM: Lymphoepithelioma is principally a tumour of the nasopharynx with only sporadic cases arising elsewhere in the head and neck. We describe the clinical and imaging features of a group of rare lymphoepitheliomas related to the palate. PATIENTS AND METHODS: Four patients with lymphoepithelioma of the palate are described. In each case we retrospectively reviewed the clinical records, laboratory results, and imaging which consisted of computed tomography (CT) and ultrasound in all four cases and magnetic resonance imaging (MRI) in two patients. RESULTS: All four patients were ethnic Chinese (non-smokers, non-drinkers). All cases were Epstein-Barr virus (EBV) related. Tumour was related to the palate in two cases and extended into the nasal cavity in one patient. The fourth patient had a tumour in the floor of the nasal cavity with invasion of the palate on biopsy but not imaging. Cervical lymphadenopathy was seen in two cases, and the nasopharynx was normal in all the four patients. CONCLUSION: Lymphoepitheliomas occur in the region of the palate, where they are also EBV related in southern Chinese. Compared with the keratinizing squamous cell carcinomas, patients with lymphoepitheliomas have a better prognosis and these tumours are not tobacco or alcohol related. They should not be misdiagnosed as metastatic nasopharyngeal carcinoma (NPC), particularly since the nasopharynx is invariably normal on imaging and adequate nasopharyngeal biopsy is negative for malignancy.

Aged↗

MR imaging of thyroglossal duct cysts in adults.

AIM: To describe the magnetic resonance (MR) features of thyroglossal duct cysts (TDC) in adults. PATIENTS AND METHODS: Sixteen patients with TDC underwent MR imaging to obtain T1- and T2-weighted images and T2-weighted fat saturation images. In addition, contrast enhanced images were obtained in five patients. RESULTS: The signal intensity of TDC was of that of a simple cyst in seven (44%) patients, yielding high signal intensity on T2- and low signal intensity on T1-weighted images. In nine (56%), the signal intensity was either intermediate or high on T1-weighted images, the T2 signal intensity in these cases being high (7), intermediate (1) or low (1). Enhancement of the wall of the cyst was present in three of five (60%) patients. All 16 TDC were located at or just to one side of the midline and 12 were embedded in the strap muscles. All TDC were infrahyoid in location but 11 also extended superiorly to be directly related to the hyoid. At the hyoid the cystic component was immediately posterior (6) anterior (3) or anterior and posterior (2) to the bone. Intralaryngeal extension was present in eight (50%) patients. A suprahyoid tract was identified in three patients. The thyroid gland was in a normal location in all patients. CONCLUSION: Thyroglossal duct cysts are most commonly of high T1 signal intensity consistent with high protein content. The tract leading to the base of the tongue is infrequently seen, the diagnosis being determined by the intimate relationship to the hyoid and strap muscles. Intralaryngeal extension in adult patients with TDC is more frequent than reported previously.

Adult↗

Carcinosarcoma of the parotid gland: ultrasound and computed tomography findings.

Carcinosarcoma is a rare tumour of the salivary gland. The ultrasound and CT appearances of a rapidly enlarging carcinosarcoma in the parotid are described. Both modalities revealed a 4-cm tumour with relatively benign features and no evidence of lymphadenopathy. Ultrasound showed a well-defined mass of homogeneous low echogenicity and posterior acoustic enhancement. Computed tomography showed a parotid mass of homogeneous attenuation similar to muscle, and homogeneous enhancement following contrast. The clue to the malignant nature of the lesion was a short indistinct superficial margin with tumour extension into the adjacent subcutaneous tissues.

Adult↗

Late radiation injury to the temporal lobes: morphologic evaluation at MR imaging.

PURPOSE: To study the morphologic characteristics of late radiation injury to the temporal lobes of the brain on magnetic resonance (MR) images. MATERIALS AND METHODS: This was a prospective study involving 34 patients (age range, 37-72 years) with known radiation injury to the temporal lobes from radiation therapy administered 2-10 years previously for nasopharyngeal carcinoma MR imaging was performed with T2-weighted gradient- and spin-echo, gradient-recalled echo, T1-weighted spin-echo, fluid-attenuated inversion-recovery, and T1-weighted postcontrast spin-echo sequences. RESULTS: Radiation injury was present in 57 of the 68 temporal lobes. The white matter lesions in radiation-induced injury were predominantly hyperintense on T2-weighted images, but in 37 (65%) of the 57 lobes, foci with heterogeneous signal intensity consistent with necrosis were detected. In the 57 involved lobes, gray matter lesions were detected in 50 (88%); blood-brain barrier disruption based on parenchymal contrast enhancement, in 51 (89%); and hemosiderin deposits, in 30 (53%). There was a significant correlation between white matter necrosis, gray matter lesions, and blood-brain barrier disruption, all of which were located mainly in the inferior temporal lobes that received the highest radiation dose. CONCLUSION: The lesion components of radiation-induced injury to the temporal lobes at MR imaging were more varied than have been previously described. In addition to the classic white matter lesions, gray matter lesions, blood-brain barrier disruption, and hemosiderin deposition also were frequently seen.

Adult↗

MR features of the denervated tongue in radiation induced neuropathy.

The MR features of the denervated tongue have been described following nerve injury from radical neck dissection and tumour invasion. The purpose of the study was to determine whether similar features are present in the tongue following radiation induced neuropathy (RIN). The clinical records and MR images of 12 patients with RIN of the hypoglossal nerve were reviewed retrospectively. T1 weighted SE images were performed in 12, T2 weighted TSE images in 11, fat suppressed images in 10 and contrast enhanced T1 weighted images in nine patients. The denervated tongue revealed "oedemalike" changes in five, fatty infiltration in six, atrophy in 11 and pseudohypertrophy in one patient. Abnormal enhancement was not identified, and in five patients the signal intensity was normal on all sequences. The oedemalike changes, fatty infiltration and normal signal intensity were seen 2-48, 2-48, and 6-63 months, respectively, after the onset of RIN. In conclusion, there was no discernible relationship between the duration of RIN and the MR appearance of the denervated tongue. Oedemalike changes, previously described in the acute/subacute phase of denervation, were also seen in long-standing disease and there was no associated abnormal enhancement in any case. Furthermore, the signal intensity may be normal, the MR diagnosis relying on asymmetry of the size of the tongue. It is postulated that radiation causes incomplete and ongoing damage of the nerve, the course of which is unpredictable.

Adult↗