Clinics in diagnostic imaging (43). Right adrenal myelolipoma

A 53-year-old woman who presented with drug-induced jaundice and urinary tract infection was incidentally found to have a large abdominal mass. Radiographs and ultrasonography showed a large fatty mass located between the right lobe of the liver and the right kidney. Diagnosis of right adrenal myelolipoma was made on computed tomography. The patient was treated conservatively. The causes of large fatty masses of the abdomen in adults are discussed, with emphasis on the imaging appearances of myelolipoma, renal angiomyolipoma, cystic teratoma and liposarcoma.     

Clinics in diagnostic imaging (66). Right complete branchial fistula

We report a case of complete branchial fistula in an 18-year-old woman which could be demonstrated by a contrast study. The tract was completely excised and the patient had an uneventful recovery. Branchial fistulae are formed due to the persistence of the embryonic second branchial cleft. Complete fistulae with the internal opening in the region of the tonsillar fossa are not common.     

Clinics in diagnostic imaging (97). Right renal tuberculous autonephrectomy

A 50-year-old man presented with recurrent episodes of right flank pain and dysuria for many years. Abdominal radiograph and intravenous urography showed extensive right renal parenchymal calcification in a lobar distribution and a non-functioning right kidney, characteristic of end-stage tuberculosis. The pathology, clinical manifestations, and radiological findings of renal tuberculosis are discussed.     

Clinics in diagnostic imaging (71). Left iliopsoas abscess secondary to vertebral osteomyelitis

A 26-year-old woman presented with a progressively painful lump at her left groin and upper thigh for five months. She also had intermittent back pain for three years. Radiographs and CT showed osteolytic destruction of the several contiguous thoracolumbar vertebrae with a large left iliopsoas abscess that extended to involve the left gluteus maximus and adductor magnus muscles. She responded well to a course of antibiotics. The role of imaging and imaging features of iliopsoas abscesses are discussed, together     

Clinics in diagnostic imaging (135). Cystic renal cell carcinoma

A 45-year-old man presented with right flank pain and haematuria for one month. Computed tomography showed a large, well-circumscribed exophytic complex cystic mass with enhanced, irregular thickened walls arising from the upper pole of the right kidney, which was associated with bilateral renal stones. Partial right nephrectomy with removal of the right renal stones was performed. Histopathology revealed papillary cell carcinoma confined to the kidney. The patient made good postoperative recovery. The Bosniak classification system of renal cystic lesions and cystic renal cell carcinoma are discussed. Various cases of renal cystic lesions and cystic renal cell carcinoma are shown.     

Clinics in diagnostic imaging (140). Iatrogenic sciatic nerve injury secondary to intramuscular injection

A 77-year-old Chinese female patient presented with acute onset of left lower limb paraesthesia and weakness after she received an intramuscular injection for pain relief in the gluteal region. Magnetic resonance (MR) imaging of her lumbosacral spine and sacral plexus was performed. The MR imaging findings are reviewed and discussed.     

Clinics in diagnostic imaging (84). Galactocoele

A 37-year-old woman who was six months postpartum presented with a painless lump in her left breast for three months. Mammograms showed a mixed fat and soft density mass on the craniocaudal and mediolateral views. A fat-fluid level was seen within the mass, typical of a galactocoele. Needle aspiration yielded milky fluid. The differential diagnosis of breast masses presenting in women with pregnancy or lactation is briefly discussed. The other causes of fat containing breast masses, such as oil cyst, hamartoma, lipoma and intramammary lymph nodes, are illustrated with additional examples.     

Clinics in diagnostic imaging (152). Right lower lobe segmental pulmonary embolus.

A 56-year-old man presented to the Accident and Emergency Department with pleuritic chest pain of sudden onset. He gave a history of short-distance air travel ten days earlier. Chest radiograph showed a peripheral-based opacity in the right lower zone, which was not seen in a previous study done three months ago, suggestive of Hampton’s hump. The D-dimer level was raised. Computed tomography pulmonary angiography confirmed the diagnosis of pulmonary embolism in a right lower lobe segmental branch, with adjacent collapsed lung, consistent with lung infarction. The patient was started on heparin injection with significant relief of his symptoms. The clinical and imaging features of pulmonary embolism are described, with emphasis on the historical radiographic signs and the current dual-energy computed tomography innovations.     

Clinics in diagnostic imaging (47). Huntington's disease

A 38-year-old man presented with progressive worsening of choreiform movements. Serum biochemistry analysis did not reveal any abnormality. Magnetic resonance imaging demonstrated symmetrical caudate nucleus atrophy and generalised cerebral strophy. Huntington's disease was diagnosed in view of the clinical presentation and the characteristic imaging findings. The clinical, pathological and imaging features of this disease process are discussed.     

Clinics in diagnostic imaging (95). Os trigonum

A 19-year-old boy presented to the Accident and Emergency Department after sustaining trauma to his left ankle and foot while playing soccer. The radiograph of his left ankle showed a well-corticated triangular fragment of bone posterior to the left talus, typical of an os trigonum. This accessory bone was initially mistaken for a fracture fragment and a plaster cast was applied. The term, do not touch lesion, has been coined to describe this group of benign bony entities which may be classified into three broad categories, namely: normal variants, lesions that are real but obviously benign, and lesions that are related to degenerative disease. The importance of recognising the characteristic radiographical appearances of these entities is emphasised, as the need for further imaging or diagnostic tests can usually be avoided.     

Clinics in diagnostic imaging (87). Subcutaneous lipoma

A 40-year-old man presented with recent increase in size of a painless long-standing soft mass over the right shoulder. Magnetic resonance (MR) imaging showed a lobulated mass located within the subcutaneous layer overlying the deltoid muscle. It was homogeneously T1-hyperintense, T2-hyperintense, and non-enhancing. Signal characteristics were those of a simple lipoma. The diagnosis was confirmed on histopathological examination of the excised specimen. Musculoskeletal lipomas are discussed, with emphasis on their characteristic appearances on various imaging modalities, and illustrated by additional examples.     

Clinics in diagnostic imaging (121). Gallbladder adenomyomatosis

Adenomyomatosis of the gallbladder is a condition of benign hyperplasia of unknown aetiology, characterised by local or diffuse thickening of the muscular layer, with invagination of the epithelium, forming Rokitansky-Aschoff sinuses. Magnetic resonance imaging features are specific and help in the definitive diagnosis of this condition. A 50-year-old obese woman presented with episodic pain in the right hypochondrium. Ultrasonography, computed tomography and magnetic resonance imaging showed typical features of adenomyomatosis, which was subsequently confirmed by laparoscopic cholecystectomy.     

Clinics in diagnostic imaging (80). Ileocolic intussusception

Intussusception is a common but life threatening gastrointestinal emergency that occurs in the infant or young child. A three-year-old boy presenting with abdominal pain and vomiting was diagnosed to have the target sign on ultrasonography. An ileocolic intussusception was initially reduced using air enema. Recurrent intussusception 12 hours later was reduced by barium enema. In the proper hands, ultrasonography has a high diagnostic accuracy rate for intussusception. For treatment, air enema is usually perferred to barium enema. Air enema is a safe, rapid, and clean procedure that has been shown to achieve a high reduction rate, comparable to that of barium enema. Ultrasonographically-guided hydrostatic reduction of intussusception has also been recently described and is an effective alternative.     

Clinics in diagnostic imaging (42). Shepherd's fracture

A 21-year-old woman presented with severe ankle pain during a soccer match. Radiographs showed a Shepherd's fracture of the talus. She responded well to conservative treatment. The imaging anatomy of the posterior talus and os trigonum is reviewed, together with radiological features of osteochondritis dissecans of the talar dome.     

Clinics in diagnostic imaging (91). Subarachnoid haemorrhage

Computed tomography (CT) is the initial radiological investigation of patients with an acute neurological event. A 64-year-old woman presenting with generalised weakness and headache for two days was diagnosed on CT to have subarachnoid haemorrhage. Digital subtraction angiography confirmed the cause to be a ruptured posterior communicating artery aneurysm. The patient was treated by neuroradiological intervention using occlusive coils. The CT features of subarachnoid haemorrhage are discussed. Accurate CT interpretation is essential to direct appropriate investigations and management in patients with stroke, particularly as acute cerebral infarction may occasionally mimic subarachnoid haemorrhage. The role of magnetic resonance (MR) imaging in evaluation of cerebral infarct is also discussed.     

Clinics in diagnostic imaging (138). Emphysematous pyelitis

We present the case of a 49-year-old woman with poorly controlled diabetes mellitus of ten years' duration. She presented to the emergency department with nonspecific left lower abdominal pain. Ultrasonography showed mild left renal hydronephrosis, but the cause was not demonstrated. Computed tomography (CT) showed a swollen left kidney with a mildly dilated collecting system containing gas and dense fluid, confirming the diagnosis of emphysematous pyelitis. Management consisted of emergency antegrade nephrostomy drainage and parenteral antibiotics. Subsequently, the patient made a good recovery and was well when discharged home after two weeks. Gas-forming infections of the genitourinary tract carry high mortality and morbidity, and usually occur in patients with poorly controlled diabetes mellitus. Escherichia coli is the most common microorganism. This case emphasises the importance of CT in making an early diagnosis of emphysematous pyelitis, which allows prompt treatment and improves prognosis.     

Clinics in diagnostic imaging (96). Plexiform neurofibromatosis

A 10-year-old boy presented with a mass on the left side of his face for many years, left ear deafness, and limited vision in the left eye. Enhanced CT of the face and neck showed a multilobulated low attenuation mass in the left parotid space, with nodularity and involvement of branches of the left facial nerve. There was a mass in the left orbital apex that extended into the left cavernous sinus, exopthalmos of the left eye, and erosion of the medial portion of the greater wing of the left sphenoid. Partial removal of the mass in the left parotid space was performed. Histopathological examination revealed plexiform neurofibromas. CT and MR imaging findings in neurofibromatosis type 1 patients with craniofacial abnormalities are discussed.     

Clinics in diagnostic imaging (49). Cerebello-tonsillar haemangioblastoma

A 39-year-old man with cerebello-tonsillar haemangioblastoma is presented,with emphasis on its morphological and imaging features. Although both computed tomography and cerebral angiography are very useful imaging modalities in helping to establish a radiological diagnosis, magnetic resonance (MR) imaging is more accurate and sensitive in depicting the lesion nature and extent. MR imaging is especially reliable in detecting multiple and other associated lesions within the central nervous system, such that a conclusive diagnosis of the von Hippel-Lindau syndrome can be made in selected cases. It is important to identify isolated haemangioblastomas as they constitute a relatively high percentage of benign resectable tumours within the posterior fossa.The differential diagnosis and imaging features of other posterior fossa tumours are also discussed.     

Clinics in diagnostic imaging (134). Testicular lymphoma

A 55-year-old man presented with a painless right scrotal mass for the past three months. Scrotal ultrasonography showed a large circumscribed hypoechoic mass with marked hypervascularity occupying almost the entire right testis. The epididymis and scrotal skin were normal. Right radical orchiectomy was performed. Histopathology revealed lymphoma, diffuse large B-cell type confined within the tunica albuginea. The patient made a good postoperative recovery. No evidence of lymphoma in other organs was demonstrated. We discuss the differential diagnosis of ultrasonographic intratesticular masses and highlight various cases of intratesticular lesions in this article.     

Clinics in diagnostic imaging (155). Incidental PDA with secondary pulmonary arterial hypertension.

We report the case of a 70-year-old man with an asymptomatic large patent ductus arteriosus (PDA) incidentally detected on triple-rule-out computed tomography (CT). CT clearly demonstrated a vascular structure connecting the descending thoracic aorta to the roof of the proximal left pulmonary artery, consistent with a PDA. Secondary pulmonary arterial hypertension was also evident on CT. The patient was eventually diagnosed with acute coronary syndrome and was successfully treated with coronary artery bypass graft surgery and concomitant patch closure of the PDA. This article aims to outline the imaging features of PDA and highlight the information provided by CT, which is crucial to treatment planning. The pathophysiology, clinical manifestations and closure options of PDA are also briefly discussed.