Is diffusion-weighted MRI sufficient for follow-up of neuroendocrine tumour liver metastases?

AIM: To assess if diffusion-weighted imaging (DWI) alone could be used for follow-up of neuroendocrine hepatic metastases. MATERIAL AND METHODS: This was a retrospective study, approved by the institutional review board. Twenty-two patients with neuroendocrine liver metastases who had undergone more than one liver magnetic resonance imaging (MRI) examination, (including DWI and using hepatocyte-specific contrast medium) were evaluated. Up to five metastases were measured at baseline and at each subsequent examination. The reference standard measurement was performed on the hepatocyte phase by one reader. Three independent readers separately measured the same lesions on DWI sequences alone, blinded to other sequences, and recorded the presence of any new lesions. RESULTS: The longest diameters of 317 liver metastases (91 on 22 baseline examinations and a further 226 measurements on follow-up) were measured on the reference standard by one reader and on three b-values by three other readers. The mean difference between DWI measurements and the reference standard measurement was between 0.01-0.08 cm over the nine reader/b-value combinations. Based on the width of the Bland and Altman interval containing approximately 95% of the differences between the reader observation and the mean of reference standard and DWI measurement, the narrowest interval over the nine reader/b-value combinations was -0.6 to +0.7 cm and the widest was -0.9 to 1 cm. In the evaluation of overall response using Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 criteria, the weighted kappa statistic was between 0.49 and 0.86, indicating moderate-to-good agreement between the reference standard and DWI. CONCLUSION: The visualisation and measurement of hepatic metastases using DWI alone are within acceptable limits for clinical use, allowing the use of this rapid technique to restage hepatic disease in patients with neuroendocrine metastases.

Pancreaticoduodenectomy: expected post-operative anatomy and complications.

Pancreaticoduodenectomy is a complex, high-risk surgical procedure performed for tumours of the pancreatic head and other periampullary structures. The rate of perioperative mortality has decreased in the past number of years but perioperative morbidity remains high. This pictorial review illustrates expected findings in early and late post-operative periods, including mimickers of pathology. It aims to familiarize radiologists with the imaging appearances of common and unusual post-operative complications. These are classified into early non-vascular complications such as delayed gastric emptying, post-operative collections, pancreatic fistulae and bilomas; late non-vascular complications, for example, biliary strictures and hepatic abscesses; and vascular complications including haemorrhage and ischaemia. Options for minimally invasive image-guided management of vascular and non-vascular complications are discussed. Familiarity with normal anatomic findings is essential in order to distinguish expected post-operative change from surgical complications or recurrent disease. This review summarizes the normal and abnormal radiological findings following pancreaticoduodenectomy.

John Thomas sign--a memorable but misleading sign in hip fractures.

OBJECTIVE: The John Thomas sign is a favourite of medical students and theorizes that in femoral neck fractures, the male member will lie to the side of the fracture on the plain radiograph. The aim of this study was to evaluate the accuracy, and examine the phenomenon of eponymous signs. We sought to answer the following questions: (1) How accurate is the sign in the context of a consecutive series of male patients with hip fractures? (2) Is there a relationship between side and size of penile lie and the side of fracture? HYPOTHESIS: That the accuracy of the John Thomas sign is, like many eponymous signs, spurious. MATERIALS AND METHODS: Two hundred male AP pelvis radiographs were examined, of which 100 had a hip fracture and compared these against 100 control films that did not. Age at presentation, and the side, length and angle of penile lie were measured. RESULTS: The results show two findings: that the accuracy of the supposed "sign" is less accurate than the toss of a coin; and that left lie and left-sided fractures are more common. We fail to show a relationship between side of fracture, John Thomas size or degree of angulation. CONCLUSION: John Thomas sign is no better than the toss of a coin in relation to hip fractures, and is not related to side of fracture, or penile attitude. We propose that the side of lie observed in male fractures may be as a result of handedness or natural underlying body asymmetry rather than as a result of the fracture. LEVEL OF EVIDENCE: Level III Case control study.

Pathological fracture of the clavicle causing subclavian pseudoaneurysm formation.

Pseudoaneurysm of the subclavian artery is a rare but serious condition generally occurring as a result of penetrating injury to the shoulder region, often iatrogenic. As well as the potential for distal ischaemia, this condition can result in compression of adjacent structures. Untreated it can lead to rupture with life-threatening haemorrhage. We describe the unusual case of a patient with a background of metastatic breast carcinoma who presented with a pseudoaneurysm of the subclavian artery secondary to a pathological fracture of the clavicle. The patient was managed surgically due to the development of necrosis of the overlying skin. Less invasive management of subclavian pseudoaneurysms has recently been described, including endovascular stenting and percutaneous thrombin injection.

Ossifying lipoma of the thigh.

Lipomas are common soft-tissue tumours that are usually found in the subcutaneous adipose tissue. Occasionally, they may contain mesenchymal elements other than adipose tissue, including osseous components. These ossifying lipomas are usually located near or within bone, and it is very rare for a lipoma with no connection to bone to contain mature osseous tissue. We describe a case of a symptomatic ossifying intramuscular lipoma of the thigh.

Aggressive angiomyxoma of the thigh.

Aggressive angiomyxoma is a rare tumour that typically occurs in the perineum in women of reproductive age. A small number of cases occurring in men have been reported, all of which were located in the low pelvis, perineum or scrotum. While benign, the tumour is locally infiltrative and consequently has a high rate of local recurrence following surgery; therefore, accurate pre-operative diagnosis is important. The characteristic location of these tumours in the low pelvis or perineum has led to speculation that aggressive angiomyxomas arise from a mesenchymal cell that is unique to the perineum. We describe a case of aggressive angiomyxoma arising in the thigh of a 54-year-old man, which we believe is the first reported instance of this rare neoplasm occurring remote from the pelvis or perineum in a male patient. Cross-sectional imaging demonstrated a well-defined mass that had low density on CT and high intensity on fluid-sensitive MR sequences. Biopsy was non-diagnostic and excision was performed. At histological analysis, the tumour exhibited the characteristic features of aggressive angiomyxoma, with bland spindle cells and large, hyalinised blood vessels in a hypocellular myxoid matrix. Extensive immunohistochemical staining further supported the diagnosis. While the imaging features of these tumours are non-specific and suggestive of myxoid neoplasms, the diagnosis should be considered whenever biopsy of a myxoid-appearing mass yields hypocellular, non-diagnostic material, despite adequate sampling.

The imaging appearances of metallosis.

Metallosis is an uncommon condition in which there is infiltration of periprosthetic soft tissues and bone by metallic debris resulting from wear of joint arthroplasties. It is often associated with significant osteolysis; therefore the identification of metallosis is an indication for revision arthroplasty. The radiographic, CT and MRI features of metallosis in a 63-year-old man who presented 16 years post-arthroplasty are described in this case report.