Clinics in diagnostic imaging. 159. Jejunal intussusception due to Peutz-Jeghers syndrome

A 21-year-old woman presented with acute onset of upper abdominal pain. A diagnosis of Peutz-Jeghers syndrome (PJS) was made based on the clinical picture of perioral pigmentation with imaging findings of transient jejunojejunal intussusceptions and small bowel polyps, and confirmed by characteristic histopathological appearances of Peutz-Jeghers polyps. PJS is a rare hereditary condition characterised by unique hamartomatous polyps, perioral mucocutaneous pigmentations, and increased susceptibility to gastrointestinal and extraintestinal neoplasms. Patients usually present with recurrent abdominal pain due to intussusception caused by polyps. Other modes of presentations include rectal bleeding and melaena. We describe the imaging findings of PJS and provide a brief review of bowel polyposis syndromes. The latter are relatively rare disorders characterised by multiple polyps in the large or small intestine, with associated risk of malignancies and other extraintestinal manifestations. Awareness of the manifestations and early diagnosis of these syndromes is crucial to prevent further complications.

Magnetic resonance imaging of diabetic foot complications

This pictorial review aims to illustrate the various manifestations of the diabetic foot on magnetic resonance (MR) imaging. The utility of MR imaging and its imaging features in the diagnosis of pedal osteomyelitis are illustrated. There is often difficulty encountered in distinguishing osteomyelitis from neuroarthropathy, both clinically and on imaging. By providing an accurate diagnosis based on imaging, the radiologist plays a significant role in the management of patients with complications of diabetic foot.

Clinics in diagnostic imaging (162). Meckel's diverticulum

A 28-year-old Chinese man presented with acute bleeding per rectum. Computed tomography showed a posterior outpouching arising from the distal ileum. The outpouching had hyperaemic walls, but no active contrast extravasation was detected. Technetium-99m pertechnetate scintigraphy showed focal areas of abnormal uptake in the right side of the pelvis, superior and posterior to the urinary bladder. These areas of uptake appeared simultaneously with the gastric uptake and demonstrated gradual increase in intensity on subsequent images. The diagnosis of Meckel's diverticulum was confirmed on surgery and the lesion was resected. The clinical and imaging features of Meckel's diverticulum are discussed.

Clinics in diagnostic imaging. 158. Duodenal ectopic pancreas

A 46-year-old man presented with right loin tenderness following a road traffic accident. Computed tomography and magnetic resonance imaging showed a well-defined, smooth, enhancing oval lesion in the wall of the first part of the duodenum. The lesion was seen separately from the normal pancreas. It showed attenuation, intensity and enhancement similar to that of normal pancreas. Based on the imaging appearance, a diagnosis of ectopic pancreas was made. The patient underwent oesophagogastroduodenoscopy, endoscopic ultrasonography and fine-needle aspiration cytology of the lesion, which confirmed ectopic pancreatic tissue. Since the patient was asymptomatic, surgical resection was deferred. The embryologic origin, various locations, imaging appearance and clinical significance of ectopic pancreas are discussed.

Clinics in diagnostic imaging (156). Golf-induced hamate hook fracture

The wrist is a common site of injury and the most frequently injured body part among professional golfers. A 37-year-old, right-handed male golfer presented with pain at the ulnar aspect of his left palm, which grew worse after an initial traumatic impact from the golf club handle. There was tenderness over the hypothenar eminence of the left palm. Computed tomography of the left wrist showed an undisplaced fracture through the base of the hamate hook. The golf-induced hamate hook fracture was managed conservatively, with cessation of physical activity involving the left hand and wrist for eight weeks. The patient made a full recovery. Repetitive trauma, exacerbated by improper wrist motion, leads to typical wrist injuries affecting golfers, such as ulnar impaction syndrome, de Quervain's disease, and tendinopathy affecting the flexor carpi ulnaris and extensor carpi ulnaris, all of which can be diagnosed on imaging.

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 (154). Carbon monoxide (CO) poisoning

A 59-year-old man with a history of major depression was found by his wife to be unconscious and foaming at the mouth. On arrival at the emergency department, the patient was noted to be unresponsive. Computed tomography of the brain showed symmetrical ill-defined areas of hypoattenuation involving the medial aspects of both lentiform nuclei, while magnetic resonance images of the brain showed symmetrical increased signal in the bilateral globi pallidi on diffusion weighted, T2-weighted and fluid attenuated inversion recovery sequences. These findings were those of acute carbon monoxide poisoning. Despite aggressive treatment, the patient's condition continued to deteriorate and he eventually passed away. The various imaging findings of carbon monoxide poisoning in the brain and the differential diagnoses are discussed.

Clinics in diagnostic imaging. 145

A 63-year-old man presented with painless jaundice, loss of appetite and significant weight loss. Cross-sectional imaging showed a diffusely enlarged pancreas, with no significant fat stranding and a hypodense rim on computed tomography, which appeared hypointense on T2-weighted magnetic resonance imaging. There was a narrowed pancreatic duct and features of common bile duct narrowing in the region of the pancreatic head. However, there was no obvious mass seen in the pancreatic head region. These features were classical of autoimmune pancreatitis with diffuse involvement of the gland. Laboratory investigation showed abnormal liver function and the classical sign of raised immunoglobulin G class 4 antibodies. The patient showed dramatic response to high-dose steroids, with resolution of both the laboratory and imaging abnormalities within one month. We discuss the classical imaging features of Type 1 autoimmune pancreatitis, an uncommon condition that needs to be differentiated from pancreatic malignancy.

Clinics in diagnostic imaging. 148. Bursal-sided partial-thickness supraspinatus tendon tear

Rotator cuff injury comprises a continual spectrum of lesions ranging from tendinopathy, which may progress to partial- or full-thickness tear. This progression may be influenced by the interplay of extrinsic and intrinsic factors. We describe the case of a 29-year-man who presented with right shoulder pain for one year. His initial magnetic resonance (MR) arthrogram showed supraspinatus tendinopathy. Subsequent MR arthrogram, obtained after a road traffic accident, showed a bursal-sided partial-thickness tear of the supraspinatus tendon. In view of his worsening clinical symptoms, surgery was performed ten months later, revealing a full-thickness rotator cuff tear near the tendon insertion, with a tight subacromial space and bony protuberance of the humeral head. The pathogenesis of rotator cuff injuries, the roles of different imaging modalities in the diagnosis of rotator cuff injuries, as well as the advantages and limitations of various radiological modalities, are discussed.

Clinics in diagnostic imaging (150)

Spontaneous spinal epidural haematoma is a rarely encountered cause of back pain. It often leads to cauda equina syndrome, necessitating emergency spinal surgery. We report the case of a 19-year-old Chinese man who presented with pain in the lower back, which started after he had carried some heavy boxes. He denied a history of fall or trauma. Magnetic resonance (MR) imaging showed a hyperintense biconvex-shaped lesion in the posterior epidural space on both T1- and T2-weighted sequences, diagnostic of a spinal epidural haematoma. The patient, who was admitted and managed conservatively, had gradual resolution of his pain. No neurological deficit was detected on discharge or on follow-up. Repeat MR imaging showed total resolution of the lumbar spinal epidural haematoma. The clinical characteristics, MR imaging features, diagnosis and management of spontaneous spinal epidural haematoma are discussed.

Clinics in diagnostic imaging (139). Displaced medial meniscus bucket-handle tear

A 58-year-old man presented with knee pain and swelling, following a previous injury. A displaced bucket-handle tear of the medial meniscus was diagnosed on magnetic resonance (MR) imaging and subsequently confirmed by arthroscopy. MR imaging is accurate in diagnosing bucket-handle tears. The different MR imaging signs of bucket-handle tears include the double posterior cruciate ligament sign, displaced fragment in intercondylar notch sign, absent bow-tie sign, anterior flipped meniscus sign and coronal truncation sign. Specificity is increased when a combination of the different imaging signs is present. Understanding the meniscal anatomy and potential mimics of the bucket-handle tear is important in order to ensure an accurate diagnosis and appropriate management.

Clinics in diagnostic imaging. 141. Complete anterior cruciate ligament tear

A 38-year-old man presented with right knee pain and swelling following a football injury. Magnetic resonance (MR) imaging showed a complete anterior cruciate ligament (ACL) tear and lateral meniscal tears. The torn ACL was repaired with a graft obtained from the semitendinosus muscle, and the menisci were debrided. The mechanisms of injury to the ACL are varied and may be due to direct or indirect contact with the knee as well as with twisting injuries. Knowledge of the ACL's normal anatomy, together with MR imaging technique and understanding of the appearance of the lesion on MR examination, is crucial to aid in the identification of an ACL tear. Diagnosis of an ACL tear should be based on direct MR imaging signs, although indirect signs may be helpful, particularly in chronic tears. Other associated injuries to be aware of include meniscal and other ligamentous injuries. Normal ACL graft and post-ACL graft reconstruction complications are also briefly discussed.

Clinics in diagnostic imaging (142). Cervical oesophagus impacted partial denture

A 58-year-old man presented to the emergency department with sudden pain and odynophagia after drinking water. The patient thought that part of his lower denture may have fallen into his throat. There was moderate tenderness over the lower anterior neck. Radiographs of the neck were normal. Computed tomography showed an impacted partial denture in the upper oesophagus, which was removed by rigid endoscopy. Recheck endoscopy showed a superficial mucosal laceration at 18 cm. Ingestion of dental prostheses is common among the elderly population. The role of imaging in the early detection of ingested foreign bodies, particularly nonradio-opaque ones, is discussed.

Wandering humeral head mimicking a breast mass

A 74-year-old woman was incidentally found to have a left breast mass. The mass could not be adequately compressed to be visualized on mammography. Ultrasonography showed a heavily-calcified rounded mass in the left axillary tail of the left breast. Chest radiograph confirmed that the mass was a migrated humeral head. Remotely-displaced fracture-dislocations of the humeral head are very rare and to our knowledge, displacement into the breast, clinically mimicking a breast mass, has not been previously described.