An 80-year-old man presented to the emergency department in August 2016 with a 2-day history of painful scrotal swelling and fever. There was no history of trauma. He had a history of hypertension, diabetes mellitus and bullous pemphigoid, and was taking long-term steroid therapy. Upon presentation, the patient had a fever of 38.8°C and fast atrial fibrillation with a heart rate of 170 beats per minute. Blood pressure was 149/104 mm Hg. Physical examination of the patient revealed scrotal skin erythema and a firm left scrotal swelling that was tender on palpation. No cough impulse could be elicited. His white cell count was 21.8 × 109 /L and blood glucose level was 21.6 mmol/L. Ultrasound of the left hemiscrotum showed a fluid collection with hyperechoic interfaces and ring-down artefact suggestive of the presence of gas, obscuring the underlying structures (Fig 1). Subsequent non-contrast computed tomographic scan of the pelvis confirmed that the mottled gas and fluid density were confined to the left hemiscrotum (Fig 2a). The left testis and epididymis were poorly delineated. There was no gas density in the subcutaneous layer of the scrotum or perineum or in the intraperitoneal cavity. There was also no evidence of indirect inguinal hernia (Fig 2b). A diagnosis of emphysematous epididymo-orchitis was made. Emergency surgery was arranged a few hours after imaging. Intra-operatively, gas and pus were seen within the left tunica vaginalis. The left epididymis was necrotic and almost destroyed but the left testis was relatively spared with friable tissue and patches of necrosis (Fig 3). Drainage of pus and left orchidectomy were performed. Pus culture revealed Escherichia coli. The patient subsequently developed septic shock and died 3 days after the operation.

Emphysematous cholecystitis, pyelonephritis, and cystitis are not uncommonly seen in patients with poorly controlled diabetes mellitus. It is nonetheless rare to see gas-forming infection of the epididymis and testis although this is also reported to be associated with diabetes mellitus.1 2 3 Long-term use of steroid in our patient may have been an additional risk factor due to immunosuppression. Based on the clinical presentation and ultrasound findings of our patient, the main differential diagnoses included Fournier’s gangrene and incarcerated indirect inguinal hernia. Computed tomographic scan was very helpful in delineating the definitive diagnosis. Gas pockets confined to the scrotal sac without involvement of the subcutaneous layer of the perineum virtually excluded the possibility of Fournier’s gangrene. Incarcerated indirect inguinal hernia was excluded due to the absence of bowel loops in the scrotal sac.

When a diabetic patient presents with acute scrotal pain and features of infection, careful examination during the initial ultrasound scan for the presence of gas within the scrotum is essential as this will alter the subsequent management plan as it implies a much poorer prognosis than non–gas-forming epididymo-orchitis.

In conclusion, emphysematous epididymo-orchitis is an uncommon but life-threatening disease. Ultrasound and computed tomographic scan are essential to identify this entity for early treatment.

All authors have made substantial contributions to the concept or design of this study; acquisition of data; analysis or interpretation of data; drafting of the article; and critical revision for important intellectual content.

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

All authors have disclosed no conflicts of interest. All authors had full access to the data, contributed to the study, approved the final version for publication, and take responsibility for its accuracy and integrity.

1. Mathur A, Manish A, Maletha M, Luthra NB. Emphysematous epididymo-orchitis: a rare entity. Indian J Urol 2011;27:399-400. Crossref

2. Mandava A, Rao RP, Kumar DA, Naga Prasad IS. Imaging in emphysematous epididymo-orchitis: a rare cause of acute scrotum. Indian J Radiol Imaging 2014;24:306-9. Crossref

3. Hegde RG, Balani A, Merchant SA, Joshi AR. Synchronous infection of the aorta and the testis: emphysematous epididymo-orchitis, abdominal aortic mycotic aneurysm, and testicular artery pseudoaneurysm diagnosed by use of MDCT. Jpn J Radiol 2014;32:425-30. Crossref

A 43-year-old Chinese man presented to United Christian Hospital, Hong Kong, in January 2016, with a 2-year history of vague right upper quadrant pain. Blood test results were unremarkable except for an episode of transient eosinophilia. Ultrasonography showed mildly dilated intrahepatic ducts. Magnetic resonance cholangiopancreatography showed diffuse and uniform mild dilatation of peripheral intrahepatic bile ducts (Fig 1) consistent with the ‘too many intrahepatic ducts’ sign (Fig 2). Notably, there was no central extrahepatic bile duct dilatation. Subsequently requested stool microscopy was positive for Clonorchis sinensis ova. The patient was given a course of praziquantel.

Clonorchiasis is a foodborne zoonosis caused by consumption of raw or undercooked freshwater fish infested by the liver fluke C sinensis. C sinensis larvae penetrate the scales of freshwater fish and encyst in subcutaneous tissues. Cysts, when consumed by a definitive host, hatch in the intestine and migrate to the biliary tree, where the adult flukes establish residence. Clonorchiasis is endemic in many parts of Asia, including China, Korea, and Vietnam.1 Clonorchiasis and its complications are not commonly seen in affluent populations, such as those in Hong Kong. However, the increasing mobility of people around the region means that clinicians should be vigilant of the condition and alert to its symptoms. Knowledge of the characteristic imaging features of clonorchiasis would prompt stool microscopy and allow early diagnosis.

Within the biliary tree, adult C sinensis flukes reside in small- or medium-sized peripheral intrahepatic ducts. The organisms cause dilatation of the intrahepatic ducts. In heavy infestations, the extrahepatic ducts, the gallbladder, or even the pancreatic duct can also be involved. The dilated peripheral ducts can be visualised by direct cholangiography, or to a better extent by magnetic resonance cholangiopancreatography (owing to the independence of rate and volume of the contrast injection), as the ‘too many intrahepatic ducts’ sign.2 Occasionally, linear or elliptical filling defects representing the flukes can be seen.3

Light infestations with C sinensis can be asymptomatic. Heavier infestations can result in fever, jaundice, right upper quadrant pain, and eosinophilia. Untreated, chronic clonorchiasis induces chronic inflammation of the bile ducts. Recurrent pyogenic cholangitis, cholelithiasis, pancreatitis, and cholangiocarcinoma are the main complications.4

Infestations are diagnosed by observation of C sinensis ova during stool microscopy. Immunological and molecular techniques of diagnosis are still at the experimental stage.1 Praziquantel is the only drug treatment for clonorchiasis that is recommended by the World Health Organization.1

In summary, clinicians in Asia should be vigilant of clonorchiasis. In modern clinical practice, magnetic resonance cholangiopancreatography is often requested for non-invasive evaluation of the biliary tree. Knowledge and recognition of the characteristic imaging features of clonorchiasis would prompt timely investigation by stool microscopy. Early diagnosis and treatment of clonorchiasis can prevent complications such as recurrent pyogenic cholangitis and cholangiocarcinoma.

The authors have no conflicts of interest to disclose.

1. World Health Organization. Foodborne trematode infections—clonorchiasis. Available from: http://www.who.int/foodborne_trematode_infections/clonorchiasis/en/. Accessed on 27 Nov 2016.

2. Choi D, Hong ST. Imaging diagnosis of clonorchiasis. Korean J Parasitol 2007;45:77. Crossref

3. Lim JH. Radiologic findings of clonorchiasis. AJR Am J Roentgenol 1990;155:1001-8. Crossref

4. Choi BI, Han JK, Hong ST, Lee KH. Clonorchiasis and cholangiocarcinoma: etiologic relationship and imaging diagnosis. Clin Microbiol Rev 2004;17:540-52. Crossref

A 58-year-old man presented with left globe rupture following blunt orbital trauma. Visual acuity was light perception only. There was lid swelling, ecchymosis, and a deformed globe with scleral laceration. Computed tomography (CT) of the orbit revealed a 3.7-mm hyperdensity at the superomedial aspect of the left globe, interpreted by the radiologist as a possible intra-orbital foreign body (Fig).

Thorough history for the mechanism of trauma, physical examination for a wound site and thin cut CT sections were reviewed. History revealed blunt orbital trauma by a metallic rod rather than a sharp penetrating injury. No cutaneous entry site was evident. Computed tomography revealed bilateral hyperdensities at the level of the trochlea, more pronounced on the left than the right, with no metallic streak artefacts. All of the above supported a diagnosis of trochlear calcification rather than an intra-orbital foreign body, and the patient subsequently underwent emergency repair of scleral laceration without orbital exploration.

The trochlea is a cartilaginous pulley at the superomedial aspect of the orbit through which the superior oblique muscle tendon passes freely. It has a synovium-lined space, and like other synovial joints of the body, the trochlea can develop calcifications in the cartilage, tendon, or within the bursa-like cleft.1 The reported prevalence of incidental trochlear calcifications on CT is 3-16%, with over 50% being unilateral.2 3 No clear cause has been identified, but prior studies have postulated degenerative, inflammatory, metabolic or traumatic aetiologies.4 Since trochlear calcification is asymptomatic, most cases go unnoticed by radiologists as well as ophthalmologists. In the presence of co-existing orbital trauma, it can be misdiagnosed as an intraorbital foreign body. Surgical exploration around the trochlear region may cause damage and scarring leading to diplopia.

Differentiation of the two entities requires history taking, physical examination, and proper imaging. A foreign body is present in one in six cases of orbital trauma, with metallic objects and glass being the most common.5 A review of the history to determine mechanism of injury is useful but may be unreliable. Examination of the skin and conjunctiva, particularly the fornices, may help detect subtle penetrating injuries. Radiological assessment includes plain films, ultrasound, CT, and magnetic resonance imaging. Plain films are limited to detection of metallic foreign bodies, and ultrasound has limited use because foreign bodies can be masked by surrounding highly reflective structures such as bone. Computed tomography is an excellent means to identify high-density objects such as metal or glass, but not organic matter. Magnetic resonance imaging is contra-indicated in metallic foreign bodies, but may be useful for organic foreign matter. Features of trochlear calcification may include symmetrical presentation and typical site at the trochlear apparatus. Its morphology has been described as comma, dot, and inverted U shape.2 In contrast, orbital foreign bodies are often unilateral with no specific size, shape, or location. Metallic foreign bodies may also generate streak artefacts.

Orbital calcifications can be incidental or pathological. It is important to recognise trochlear calcifications as distinct from foreign bodies so as to avoid unnecessary surgical exploration in the presence of orbital trauma.

1. Sobel RK, Goldstein SM. Trochlear calcification: A common entity. Orbit 2012;31:94-6. Crossref

2. Xiao TL, Kalariya NM, Yan ZH, et al. Trochlear calcification and intraorbital foreign body in ocular trauma patients. Chin J Traumatol 2009;12:210-3.

3. Shriver EM, McKeown CA, Johnson TE. Trochlear calcification mimicking an orbital foreign body. Ophthal Plast Reconstr Surg 2011;27:143-4. Crossref

4. Buch K, Nadgir RN, Tannenbaum AD, Ozonoff A, Fujita A, Sakai O. Clinical significance of trochlear calcifications in the orbit. AJNR Am J Neuroradiol 2014;35:573-7. Crossref

5. Nasr AM, Haik BG, Fleming JC, Al-Hussain HM, Karcioglu ZA. Penetrating orbital injury with organic foreign bodies. Ophthalmology 1999;106:523-32. Crossref

A 4-year-old girl was admitted with a 2-day history of a high temperature up to 41°C. She developed sudden-onset generalised tonic-clonic seizure. She had no travel history. Physical examination showed neck stiffness. The working diagnosis was meningitis. Non-contrast computed tomographic (CT) brain prior to lumbar puncture revealed clustered well-defined cystic lesions with no calcifications measuring up to 1.5 cm in the white matter of the right frontal and parietal lobes (Fig 1).

The child subsequently developed status epilepticus. The neurosurgical unit was consulted and brain abscesses were suspected. In view of her clinical deterioration, burr hole and aspiration of the cystic lesions were planned after magnetic resonance imaging (MRI). The signal intensity of the lesions was identical to that of cerebrospinal fluid (CSF) on all MRI sequences (Figs 2 and 3). There was no rim enhancement around the lesions. Minimal fluid-attenuated inversion recovery (FLAIR) hyperintense signals were noted in the white matter adjacent to the lesions. There was no restricted diffusion on diffusion-weighted imaging.

Imaging features were not compatible with brain abscess so surgical aspiration was withheld. Cerebral hydatid disease was considered a possible diagnosis based on imaging and the child was commenced on oral albendazole 15 mg/kg/day. This diagnosis was subsequently disproved given the lack of an exposure history, absence of Echinococcus granulosus antibody in serum, and absence of cysts in the liver and spleen on ultrasonography.

Influenza A virus antigen was subsequently detected in nasopharyngeal aspirate. The child was prescribed antiviral treatment with consequent cessation of seizures and clinical improvement. The clinical diagnosis was influenza virus–associated encephalopathy.

Follow-up CT and MRI 3 weeks later showed the non-enhancing cystic lesions to be unchanged in size and signal characteristics. The lesions were classified as giant tumefactive perivascular spaces (GTPVS).

The perivascular spaces (PVS) of the brain are pial-lined, interstitial fluid-filled cystic spaces. They accompany penetrating arteries as they enter the brain parenchyma. These are normal structures that can be found in all ages.1 Most PVS are small in size and usually measure less than 5 mm.1 Larger (>1 cm) PVS have been reported and these are called GTPVS, which can occur as single or multiple clustered cysts.2 Such GTPVS in cerebral white matter can have mild FLAIR hyperintensities in the surrounding white matter1 that can be due to gliosis.2

Of note, GTPVS are often incidental findings on imaging. They occur in characteristic locations alongside penetrating vessels in the mesencephalothalamic area, cerebral white matter, and cerebellar dentate nuclei.2 They follow the CSF signal on MRI and do not enhance.

Sometimes, GTPVS can be misinterpreted as other pathological processes.1 2 3 Lack of a solid component and complete suppression on FLAIR differentiates them from cystic neoplasms.1 Nil to minimal peri-lesional FLAIR signals help to differentiate them from cystic infarction and mucopolysaccharidosis. Parasitic cysts, in particular hydatid cysts, can have identical imaging features and necessitate clinical correlation for exclusion as in this case. Neuroepithelial cysts also have identical imaging features but can only be differentiated from GTPVS by histopathology.1 Knowledge of this entity, its imaging features, and characteristic locations is essential to avoid unnecessary medical treatment and surgical biopsy/intervention.

1. Kwee RM, Kwee TC. Virchow-Robin spaces at MR imaging. Radiographics 2007;21:1071-86. Crossref

2. Salzman KL, Osborn AG, House P, et al. Giant tumefactive perivascular spaces. AJNR Am J Neuroradiol 2005;26:298-305.

3. Sankararaman S, Velayuthan S, Ambekar S, Gonzalez-Toledo E. Giant tumefactive perivascular spaces: A further case. J Pediatr Neurosci 2013;8:108-10. Crossref

Indwelling urinary catheters are generally safe but may be associated with complications. Although intraperitoneal or extraperitoneal perforation is rare, the condition can be life-threatening.1 Abdominopelvic computed tomography (CT) is commonly performed in hospitalised patients. In many cases the urinary bladder is catheterised and included in the scan; CT scan is a reliable method to evaluate many pathologies of the urinary bladder.2 The apparent extraluminal position of a Foley catheter tip or balloon can be misleading, however.3 We present a case in which a Foley catheter balloon was inflated in a bladder diverticulum mimicking an extraluminal location on a CT scan.

A 68-year-old man was admitted with abdominal distension and suprapubic pain in April 2016. He was a visitor to Hong Kong and had a history of recurrent acute urinary retention. A urethral Foley catheter had been inserted in his home country a week before presentation and he travelled to Hong Kong with the catheter in situ. A urological assessment was scheduled on his return home. He had a history of open left nephrectomy performed over 20 years ago for urinary stone disease but otherwise had good medical history.

On presentation he was afebrile and normotensive. The abdomen was grossly distended with suprapubic tenderness and a general surgeon was consulted. Digital rectal examination revealed a grossly enlarged non-suspicious prostate. Clear urine and good urine outputs from the Foley catheter were noted. Laboratory tests showed an elevated white blood cell count of 14.5 x 10⁹ /L and normal creatinine level of 125 µmol/L. A nasogastric tube was inserted with a working diagnosis of intestinal obstruction. An urgent contrast CT scan revealed grossly dilated small bowel loops with free fluid in the pelvis and paracolic gutters. The wall of the urinary bladder was thickened with a large prostate and intravesical prostatic protrusion (Fig 1). The tip of the Foley catheter appeared to be at an extravesical location (Fig 2).

A urological opinion was sought and the patient underwent exploratory laparotomy. Intra-operatively, the tip of the Foley catheter and balloon were noted inside a large 5-cm bladder diverticulum at the dome of the urinary bladder. There was a 5-mm concealed perforation at the bladder diverticulum with surrounding dusky tissue covered by slough. Bladder diverticulectomy was performed. The urinary bladder was closed in a two-layer fashion and confirmed water-tight. No bowel injury was evident and an extensive washout was performed. A pelvic drain and 18F Foley catheter were inserted.

Postoperatively, the patient progressed well. Diet was resumed on postoperative day 3 and the drain was removed. There were no wound complications and the patient was fit for discharge on day 5. He returned to his home country with the Foley catheter in situ. We advised maintenance of bladder drainage until surgery for benign prostate hyperplasia could be performed.

This case concurs with a previous report that extraluminal location of a Foley catheter balloon on imaging can be misleading.3 Exploratory laparotomy based on the radiological findings alone may not be appropriate, especially when the clinical suspicion of bladder perforation is low. Further studies including cystogram should be considered in case of doubt.

1. White SA, Thompson MM, Boyle JR, Bell PR. Extraperitoneal bladder perforation caused by an indwelling urinary catheter. Br J Surg 1994;81:1212. Crossref

2. Caoili EM, Cohan RH, Korobkin M, et al. Urinary tract abnormalities: initial experience with multi-detector row CT urography. Radiology 2002;222:353-60. Crossref

3. Abadi S, Brook OR, Solomonov E, Fischer D. Misleading positioning of a Foley catheter balloon. Br J Radiol 2006;79:175-6. Crossref