Elastography in the evaluation of liver allograft.

Elastography is an established technique in the evaluation of chronic liver diseases. While there is a large clinical experience and data available regarding the performance of elastography in native liver, elastography experience with liver grafts is limited and still growing. Both ultrasound-based elastography techniques and MR Elastography (MRE) are useful in the assessment of liver fibrosis in liver transplants. Technical modifications for performing elastography will be required for optimum evaluation of the graft. In general, caution needs to be exercised regarding the use of elastography immediately following transplantation as post-operative changes, perioperative conditions/complications, inflammation, and rejection can cause increased stiffness in the graft. In the follow-up, detection of increased stiffness with elastography is useful for predicting development of fibrosis in the graft. Adjunctive MRI or ultrasound with Doppler also provides comprehensive evaluation of anatomy, vascular anastomosis and patency, biliary tree, and stiffness for fibrosis. In this review, we provide a brief overview of elastography techniques available followed by the literature review of elastography in the evaluation of grafts and illustration with clinical examples.

Gadolinium-based relative contrast enhancement in primary sclerosing cholangitis: additional benefit for clinicians?

AIM: To evaluate the benefit of extracellular gadolinium-based contrast agent (GBCA) enhanced magnetic resonance imaging (MRI) in addition to conventional non-enhanced T2-weighted imaging (WI) for quantification of inflammatory or fibrotic alterations in the liver parenchyma of patients with primary sclerosing cholangitis (PSC). MATERIAL AND METHODS: MRI (3 T) examinations were reviewed retrospectively by two radiologists in 27 PSC patients (age 42.9±15.6 years), and 19 controls. Regions of interest (ROIs) were drawn onto T2 hyperintense and T2 isointense areas and copied to section position matched non-enhanced and delayed-phase contrast-enhanced T1WI. Signal intensities (SI) obtained from ROIs of the multiphase T1WI were used to calculate relative liver enhancement (RLE). The interobserver agreement of RLE and quantified T2 signal was calculated using Bland-Altman analysis. RLE assessed for both T2 hyperintense (RLEhyper) and T2 isointense (RLEiso) areas were compared in patients and controls (RLEhealthy). RESULTS: The interobserver agreement of RLE in affected hyperintense areas (bias -0.77, limits of agreement -51.7 to 50.1) was superior to the quantification of T2 signal only in these areas (bias -3.35, limits of agreement -162.4 to 155.7). The RLEhyper (86.2±9.7%) was higher than the RLEiso (59.8±6.2%, p=0.03) and the RLEhealthy (53.2±2.7%, p=0.002). The mean RLEiso was not significantly different from the RLEhealthy (p=0.3). CONCLUSION: The extracellular gadolinium-based RLE of T2 hyperintense areas could be a useful add-on for routine follow up MRI in the detection of early inflammatory changes, possibly preceding formation of fibrotic scarring in PSC patients, if validated in larger cohorts.

MRI for transformation of preserved organs and their pathologies into digital formats for medical education and creation of a virtual pathology museum. A pilot study.

AIM: To evaluate the feasibility of magnetic resonance imaging (MRI) for the transformation of preserved organs and their disease entities into digital formats for medical education and creation of a virtual museum. MATERIALS AND METHODS: MRI of selected 114 pathology specimen jars representing different organs and their diseases was performed using a 3 T MRI machine with two or more MRI sequences including three-dimensional (3D) T1-weighted (T1W), 3D-T2W, 3D-FLAIR (fluid attenuated inversion recovery), fat-water separation (DIXON), and gradient-recalled echo (GRE) sequences. Qualitative assessment of MRI for depiction of disease and internal anatomy was performed. Volume rendering was performed on commercially available workstations. The digital images, 3D models, and photographs of specimens were archived into a workstation serving as a virtual pathology museum. RESULTS: MRI was successfully performed on all specimens. The 3D-T1W and 3D-T2W sequences demonstrated the best contrast between normal and pathological tissues. The digital material is a useful aid for understanding disease by giving insights into internal structural changes not apparent on visual inspection alone. Volume rendering produced vivid 3D models with better contrast between normal tissue and diseased tissue compared to real specimens or their photographs in some cases. The digital library provides good illustration material for radiological-pathological correlation by enhancing pathological anatomy and information on nature and signal characteristics of tissues. In some specimens, the MRI appearance may be different from corresponding organ and disease in vivo due to dead tissue and changes induced by prolonged contact with preservative fluid. CONCLUSIONS: MRI of pathology specimens is feasible and provides excellent images for education and creating a virtual pathology museum that can serve as permanent record of digital material for self-directed learning, improving teaching aids, and radiological-pathological correlation.

Prognostic value of different CT measurements in early therapy response evaluation in patients with metastatic colorectal cancer.

OBJECTIVES: Patients with advanced stage colorectal carcinoma (CRC) display hepatic metastases on initial staging in up to 20% of cases. The effectiveness of chemotherapy is generally evaluated by computed tomography (CT) imaging using standardized criteria (RECIST). However, RECIST is not always optimal, and other criteria have been shown to correlate with pathologic response and overall survival. The aim of this study was to evaluate the prognostic value of different CT measurement for response assessment after initiation of chemotherapy in patients with synchronous colorectal cancer liver metastases. METHODS: Fifty-five patients with CRC and synchronous hepatic metastases were evaluated retrospectively at 2 academic centers. Different size, volume, ratio and attenuation parameters were determined at baseline and after 3 cycles of chemotherapy. The prognostic value of baseline measurements and of the change between baseline and second measurements was analyzed using Kaplan-Meier estimates. RESULTS: Median time to progression was 279 days, median overall survival was 704 days. In this selective patient population, neither a significant prognostic value of initial baseline CT parameters nor a prognostic value of the change between the first and the second CT measurements was found. CONCLUSION: Initial morphological response assessment using different CT measurements has no prognostic value concerning time to progression or overall survival in patients with synchronous colorectal liver metastases.

Unusual case of unrepaired omphalocoele and uncorrected tetralogy of Fallot in a young adult.

An omphalocoele is a congenital defect that affects the development of the abdominal wall in the umbilical region, resulting in a hernial-type sac of variable size. The condition is usually diagnosed prenatally and corrected in early infancy to prevent rupture of the covering membranes, which carries a high mortality and morbidity rate. Tetralogy of Fallot is the most common cyanotic congenital heart defect during infancy that is associated with this condition. Most patients experience cyanosis at birth and die in childhood if there is no surgical intervention. Overall, it is uncommon for untreated patients with both omphalocoele and tetralogy of Fallot to survive into adulthood. We report the rare case of a 17-year-old young adult with untreated omphalocoele and uncorrected tetralogy of Fallot.

Pericardiophrenic artery embolisation for control of massive haemoptysis.

Non-bronchial systemic arteries, apart from normal and anomalous bronchial arteries, may be a source of massive haemoptysis in a chronically inflamed lung via transpleural anastomoses. Transcatheter embolisation is an established therapeutic method of choice in the management of massive haemoptysis. We report embolisation of a hypertrophied pleural branch of the pericardiophrenic artery for the management of massive haemoptysis in a 61-year-old woman. Initial computed tomography chest imaging showed peribronchial thickening and subpleural scarring in the lingula lobe, with ground-glass changes secondary to haemoptysis. Angiography demonstrated a hypertrophied branch of the left pericardiophrenic artery supplying an abnormal bunch of vessels in the lingula and anastomosing with the homolateral inferior phrenic artery. This was successfully embolised with gel foam. The left internal thoracic artery was later embolised in order to control the repeat haemoptysis. A brief anatomical review of the source of massive haemoptysis, anatomy of the internal thoracic and pericardiophrenic arteries and the clinical implications are discussed.

MR imaging features of fibroepithelial ureteral polyp in a patient with duplicated upper urinary tract.

We describe the magnetic resonance (MR) imaging features of a rare case of fibroepithelial polyp (FEP) in a duplicated upper urinary tract. The FEP appeared as a T2-hyperintense and T1-isointense filling defect within the dilated lower moiety ureter. Post gadolinium-enhanced images revealed enhancement of the FEP without ureteral wall-thickening or enhancement. Retrograde ureterography confirmed the findings, and the patient underwent ureterotomy and removal of the polyp. Histopathological findings were consistent with an FEP. It may be possible to differentiate FEP from an ureteric carcinoma based on MR imaging features. MR imaging may be useful for preoperative diagnosis of a benign ureteric tumour, and may thus prevent an unnecessary nephroureterectomy.

Clinics in diagnostic imaging (131). Multiple visceral mycotic aneurysms.

Multiple visceral arterial mycotic aneurysms are very uncommon. We present a case of a 51-year-old male intravenous drug abuser who initially presented with intracranial haemorrhage secondary to a ruptured intracranial mycotic aneurysm. The haematoma was surgically evacuated. The postoperative recovery period was complicated by distension of the abdomen and a drop in the haematocrit and haemoglobin levels. Computed tomography of the abdomen demonstrated mycotic aneurysms in the spleen and right kidney. The splenic aneurysm had ruptured, resulting in haemoperitoneum. The aneurysm was successfully treated with embolisation, and the multiple renal artery aneurysms were managed with antibiotics and clinical follow-up. During the two-year follow-up period, no further episodes of bleeding were encountered. Intravenous drug abuse is associated with a high risk of infective endocarditis and the development of mycotic aneurysms, which can rupture and result in life-threatening bleeding. Multiple visceral mycotic aneurysms can be managed with a combination of endovascular treatment and antibiotic therapy.

Accuracy of preoperative CT for local staging in colorectal carcinomas.

INTRODUCTION: This study aimed to determine the accuracy of computed tomography (CT) in the evaluation of local tumour invasion and regional lymphadenopathy in colorectal carcinomas. METHODS: A total of 99 consecutive patients who had undergone a contrast-enhanced CT within two weeks prior to surgery with histopathological confirmation of colorectal carcinoma were selected. Intravenous contrast-enhanced CT was performed with a 5-7 mm collimation. Axial images were retrospectively and independently reviewed by two radiologists (R1 and R2) who were blinded to the surgical findings and histopathology. The readers assessed the primary tumour according to modified CT staging criteria. The radiological assessment was then compared with the surgical findings and histopathology for accuracy and inter-observer agreement. RESULTS: At histopathology, the T-stage of the tumours was T2 in five, T3 in 62 and T4 in 32 patients, and the N-stage was N0 in 36, N1 in 28 and N2 in 35 patients. The accuracy of CT for T-stage and N-stage for the two readers was 45.5 percent and 60.6 percent (kappa is 0.30) and 33.3 percent and 45.4 percent (kappa is 0.23), respectively. The understaging and overstaging by R1 and R2 was 40.4 percent, 21.2 percent and 14.1 percent, 17.2 percent for T-stage and 22.2 percent, 37.4 percent and 32.3 percent, 28.3 percent for N-stage. The accuracy of serosal invasion for R1 and R2 (tumour perforates the visceral peritoneum or directly involves the adjacent organs) was 63.6 percent and 66.7 percent (kappa is 0.51), respectively. The understaging and overstaging by R1 and R2 for serosal invasion was 24.1 percent, 12.1 percent and 20.1 percent, 12.1 percent, respectively. CONCLUSION: Our study results show that the accuracy for CT staging of colorectal carcinomas for T-stage and in particular, serosal invasion, is moderate, but it is relatively low for N-stage.

Clinics in diagnostic imaging (128). Portal pyaemia.

A 66-year-old man presented with epigastric pain. Computed tomography (CT) of the abdomen showed portal venous gas with partial thrombosis of the portal veins, consistent with portal pyaemia. CT also showed nonspecific peripancreatic fat stranding. The patient was treated conservatively but did not improve, necessitating a laparotomy that revealed ischaemic colitis and bowel necrosis. He underwent a right hemicolectomy and showed clinical improvement. Portal pyaemia is a combination of infection and thrombosis within the portal veins. The presence of gas in the portal vein is a known feature in portal pyaemia. We showed radiological examples of hepatic and portal venous gas in several patients who presented to our institution, with a brief discussion of their radiological findings, causes, management and outcome. The mortality rate of patients with portal venous gas depends on the underlying cause. The high mortality rate of patients with portal venous gas due to bowel necrosis or ischaemia may necessitate emergent surgical intervention.

Clinics in diagnostic imaging (119). Post-traumatic intracerebral pneumatocele.

A 36-year-old man presented with cerebrospinal fluid rhinorrhoea after head injury in a road traffic accident three weeks prior to presentation. Magnetic resonance (MR) imaging demonstrated a hypointense cavity in the left frontal lobe communicating with the frontal horn of the left lateral ventricle, consistent with an intracerebral pneumatocele. The fistulous track communicating with the frontal sinus was demonstrated on the sagittal and coronal images. The patient underwent surgical decompression of the cavity and repair of the dural defect and fracture of the frontal bone. Postoperatively, the patient made excellent recovery. An intracerebral pneumatocele should be recognised on MR imaging, as potential complications include tension pneumocephalus and meningitis, and surgical treatment is indicated in most of the cases.

Clinics in diagnostic imaging (117).

A 76-year-old woman presented with a five-day history of fever and abdominal pain. Her urine culture grew Candida albicans. She was treated with intravenous antibiotics, as having a urinary tract infection, but her fever persisted. Computed tomography of the abdomen showed a cystic mass at the pancreatic head and uncinate process with peripancreatic lymph nodes. Given the patientos high operative risk and her clinical picture favouring sepsis, endoscopic ultrasonographical fine-needle aspiration (EUS-FNA) which was performed, revealed pus with acid-fast bacilli seen in the cell block material. The patient was started on antituberculous medication with rapid improvement of symptoms. Pancreatic tuberculosis (TB) is rare and can mimic pancreatic carcinoma both clinically and radiologically. Histological diagnosis is crucial before administration of appropriate therapy. The usefulness of EUS-FNA and its pitfalls, as well as the other radiological modalities for the evaluation and assessment of pancreatic TB are discussed.

Endovascular management of pseudoaneurysms of the splenic artery: experience with six patients.

The purpose of this paper was to describe our experience with the endovascular management of splenic artery pseudoaneurysms (SAPA). Seven patients with documented SAPA on CT and/or angiography were considered for endovascular treatment. The pseudoaneurysms were located in the main splenic artery (n = 4) or its branches (n = 3). In one patient in whom the pseudoaneurysm was located in a hilar branch, selective catheterization of splenic artery failed. Metallic coils (n = 1), gelfoam and hydrogel particles (n = 1), metallic coils and gelfoam (n = 2), metallic coil, gelfoam and acrylic glue (n = 2) were used as embolization material in the remaining six patients. These patients were followed for a mean period of 11.3 months. Transcatheter embolization was successful in five patients with no procedure-related complications. In one patient, embolization was incomplete and the patient underwent surgery, but died on the 10th postoperative day because of irreversible shock. Another patient, after successful embolization, underwent surgery for management of an associated pseudocyst. Endovascular treatment is a safe and effective method of management of SAPA.

Macronodular hepatic tuberculosis associated with portal vein thrombosis and portal hypertension.

Tuberculosis (TB) of the liver is usually associated with miliary spread. Macronodular TB of the liver is rare. A case of macronodular TB of the liver in a 31-year-old woman causing portal vein thrombosis and portal hypertension is presented. Ultrasound and CT appearances are described. There was coexistent ileo-caecal TB with extensive mesenteric and retroperitoneal lymphadenopathy. Macronodular TB should be considered in the differential diagnosis when a patient presents with multiple calcified masses in the liver with portal vein thrombosis and portal hypertension.

Diffusion MR imaging for cerebral abscess.

We report a case of cerebral abscess, which ruptured into the lateral ventricle. The radiological features on conventional MRI, appearance on both diffusion weighted images (DWI) and apparent diffusion coefficient (ADC) maps are described.

MR appearance of interpeduncular lipoma.

Interpeduncular lipoma (IPL) is a very rare benign intracranial lesion. Non-invasive diagnosis of this condition is important, as these lesions are usually asymptomatic and are found incidentally. We describe a rare case of IPL in a 35-year-old woman presenting with headache of long duration and a recent increase in severity and frequency of headache. There was no neurological abnormality on clinical examination. MR imaging demonstrated a homogeneous lobulated T1-hyperintense and T2-hypointense lesion in interpeduncular fossa. A T1-weighted fat suppression sequence with chemical shift method confirmed the fatty nature of the lesion. The patient was managed conservatively.

MRI demonstration of unsuspected intraventricular rupture of pyogenic cerebral abscesses in patients being treated for meningitis.

We report three patients with pyogenic meningitis who showed a partial response to medical treatment. MRI demonstrated an unsuspected brain abscess with intraventricular rupture, a possible cause of the partial response to treatment.