Retrospective comparison of ultrasound guided percutaneous and open skeletal muscle biopsies.

BACKGROUND: Open skeletal muscle biopsy has been the mainstay of sample retrieval in patients with suspected muscle diseases. However, this technique is limited by surgeon and theatre availability, potentially resulting in delayed diagnosis and increasing hospital stay. AIMS: To compare the effectiveness and timeliness of ultrasound guided 14-gauge needle percutaneous muscle biopsy in comparison with open biopsy. METHODS: We performed a retrospective chart review on 19 inpatients who underwent ultrasound-guided percutaneous muscle biopsy using a 14-gauge needle and 19 consecutive inpatients who underwent open surgical muscle biopsy between January 2017 and June 2019. Patient demographics, length of stay, biopsy sample size and the correlation between histological and clinical diagnosis were compared between groups. RESULTS: The median age of both groups was 64 years. Seventy-nine percent of surgical patients were female compared with 58% who had percutaneous biopsy. Surgical biopsies yielded larger samples (median 864 mm3 vs 17 mm3 , P = 0.03). While there was no difference in the length of inpatient stay (median 8 days), patients who had percutaneous biopsy had a shorter referral to procedure time (median 3 days vs 5 days, P = 0.012). Eighty-four percent of patients underwent MRI prior to percutaneous muscle biopsy, whereas only 16% had imaging before surgical biopsy (P ≤ 0.001). Most surgical biopsies were performed on the quadriceps whereas a wide range of muscles were sampled using the percutaneous technique. Overall, the percutaneous muscle sample was non-diagnostic in five cases (26%) despite a clinical diagnosis of myopathy. By comparison, two surgically obtained samples (11%) were non-diagnostic. CONCLUSION: Ultrasound guided percutaneous muscle biopsies were performed faster and a wider range of muscles were targeted. However, this technique yielded smaller samples, which were non-diagnostic in 26% of cases. Increasing the needle gauge or number of passes may improve the diagnostic yield of this technique.

Indirect Lung Absorbed Dose Verification by 90Y PET/CT and Complete Lung Protection by Hepatic Vein Balloon Occlusion: Proof of Concept.

Postradioembolization lung absorbed dose verification was historically problematic and impractical in clinical practice. We devised an indirect method using 90Y PET/CT. Methods: Conceptually, true lung activity is simply the difference between the total prepared activity minus all activity below the diaphragm and residual activity within delivery apparatus. Patient-specific lung mass is measured by CT densitovolumetry. True lung mean absorbed dose is calculated by MIRD macrodosimetry. Results: Proof of concept is shown in a hepatocellular carcinoma patient with a high lung shunt fraction of 26%, where evidence of technically successful hepatic vein balloon occlusion for radioembolization lung protection was required. Indirect lung activity quantification showed the postradioembolization lung shunt fraction to be reduced to approximately 1% with a true lung mean absorbed dose of approximately 1 Gy, suggesting complete lung protection by hepatic vein balloon occlusion. Conclusion: We discuss possible clinical applications such as lung absorbed dose verification, refining the limits of lung tolerance, and the concept of massive activity radioembolization.

Prognostic role of alpha-fetoprotein in patients with hepatocellular carcinoma treated with repeat transarterial chemoembolisation.

BACKGROUND: Repeat transarterial chemoembolisation (rTACE) is often required for hepatocellular carcinoma (HCC) to achieve disease control, however, current practice guidelines regarding treatment allocation vary significantly. This study aims to identify key factors associated with patient survival following rTACE to facilitate treatment allocation and prognostic discussion. METHOD: Patients with HCC undergoing rTACE at six Australian tertiary centers from 2009 to 2014 were included. Variables encompassing clinical, tumour, treatment type and response factors were analysed against the primary outcome of overall survival. Univariate analysis and multivariate Cox regression modelling were used to identify factors pre- and post-TACE therapy significantly associated with survival. RESULTS: Total of 292 consecutive patients underwent rTACE with mainly Child Pugh A cirrhosis (61%) and BCLC stage A (57%) disease. Median overall survival (OS) was 30 months (IQR 15.2-50.2) from initial TACE. On multivariate analysis greater tumour number (p = 0.02), higher serum bilirubin (p = 0.007) post initial TACE, and hepatic decompensation (p = 0.001) post second TACE were associated with reduced survival. Patients with serum AFP ≥ 200 ng/ml following initial TACE had lower survival (p = 0.001), compared to patients with serum AFP level that remained < 200 ng/ml post-initial TACE, with an overall survival of 19.4 months versus 34.7 months (p = 0.0001) respectively. CONCLUSION: Serum AFP level following initial treatment in patients undergoing repeat TACE for HCC is a simple and useful clinical prognostic marker. Moreover, it has the potential to facilitate appropriate patient selection for rTACE particularly when used in conjunction with baseline tumour burden and severity of hepatic dysfunction post-initial TACE.

Magnetic resonance imaging for common peroneal nerve injury in trauma patients: Are routine knee sequences adequate for prediction of outcome?

INTRODUCTION: Common peroneal nerve (CPN) injury occurs in 10-40% of patients following knee dislocation. Is magnetic resonance imaging (MRI) using routine knee protocols able to adequately evaluate CPN injury and predict long-term outcome? METHODS: Trauma patients presenting for knee MRI at a single public hospital, between July 2007 and May 2017, were retrospectively identified using radiology and orthopaedic databases. Medical records were retrieved for clinical scores. MRI images were scored by two independent radiologists blinded to the clinical CPN status and scores correlated with initial clinical scores using the Pearson correlation coefficient. RESULTS: Final cohort included 107 patients (81 males and 26 females) with a mean age of 39 (range 19-81 years). MRI was considered to be adequate for coverage of the CPN in 84 patients. Fourteen patients had CPN injury clinically (seven complete and seven partial). Concordance between MRI scores and initial clinical scores was 0.456 (P = 0.01). MRI sensitivity and specificity for CPN injury on the 84 adequate scans were 54.5% and 93.2% respectively. All seven cases of partial CPN injury and three of seven cases of complete CPN injury recovered fully. High MRI scores of 5 and 8 were given for the two patients with a persisting complete CPN palsy. Highest scores for partial CPN injury subjects were 2 and 4. CONCLUSIONS: Magnetic resonance imaging using a routine knee protocol is not adequate for the assessment of CPN injury in many subjects. More specific MRI neural sequences with complete CPN coverage may be worth trialing.

Hepatic contrast-enhanced ultrasound: impact of its introduction in the Australian context.

INTRODUCTION: Contrast-enhanced ultrasound (CEUS) is a relatively new imaging modality in Australia. We discuss our early experience with CEUS at Royal Melbourne Hospital in assessment of focal liver lesions and its clinical impact. METHOD: Radiology department and hospital computerised information systems were used to identify and collate information regarding the indication, previous and follow-up imaging, CEUS findings and subsequent final diagnoses of patients who underwent hepatic CEUS from 12/12/2007 to 20/4/2012. RESULTS: A total of 388 hepatic CEUS were performed, examining 409 lesions. The cases were grouped as either 'initial study' or 'follow-up' group, with main focus on the former group. Of the 367 lesions in the 'initial study' group, CEUS was able to distinguish benign from malignant pathology in 344 cases (93.8%). This was especially beneficial in setting of known malignancy with indeterminate liver lesions found on CT to confidently exclude metastatic disease. For 124 of 162 patients who had an incidentally detected indeterminate liver lesion, CEUS was the final imaging investigation required to make a diagnosis. CONCLUSION: CEUS is a valuable tool in assessment of focal liver lesions in conjunction with other conventional modalities in a variety of clinical settings. In particular, it provided definitive diagnosis in a significant proportion of incidentally identified liver lesions many of which are benign, saving patient anxiety and further unnecessary follow-up.

Diagnostic challenges and pitfalls in MR imaging with hepatocyte-specific contrast agents.

The use of gadolinium-based hepatocyte-specific contrast agents (HSCAs) has increased markedly since their introduction, and hepatocellular phase imaging performed with an HSCA is now a key part of the standard magnetic resonance (MR) imaging work-up for focal liver lesions. An understanding of the mechanisms of action of HSCAs helps ensure their effective use. The optimal delay for hepatocellular phase image acquisition differs between the two currently available HSCAs, gadoxetic acid and gadobenate dimeglumine, and MR imaging protocols must be adjusted accordingly. In addition, familiarity with typical and atypical appearances of benign and malignant focal liver lesions at HSCA-enhanced hepatocellular phase MR imaging, along with knowledge of the processes that are most likely to produce atypical appearances, is required to achieve optimal diagnostic accuracy.

Assessing signal intensity change on well-registered images: comparing subtraction, color-encoded subtraction, and parallel display formats.

PURPOSE: To assess the sensitivity, specificity, accuracy, and interobserver reliability of subtraction, color-encoded subtraction, and parallel display formats in assessing signal intensity (SI) differences between well-registered images. MATERIALS AND METHODS: Institutional ethics approval for the study and a waiver of individual patient consent were obtained. Five radiologists graded the severity of fatty liver by using a seven-point scale for four imaging sets created from 179 pairs of dual-echo in- and opposed-phase magnetic resonance images from 179 patients. The four sets contained images displayed in parallel, subtraction images, color-encoded subtraction images, and images from the three previous formats presented together. The order of the images and sets was randomized. Sensitivity and specificity were assessed with the McNemar test. Accuracy was assessed by using three-way analysis of variance, with Tukey post hoc methods used to assess differences between the four formats. Interobserver reliability was assessed by using the Fleiss κ value. RESULTS: Subtraction (P = .016 at a 5% SI difference threshold) and color-encoded subtraction (P = .031 at a 4% SI difference threshold) formats had higher sensitivity than did the parallel format. The accuracy of the subtraction format was superior to that of the parallel format (P < .0001). Interobserver reliability of the subtraction (κ = 0.53) and color-encoded subtraction (κ = 0.39) formats was superior to that of the parallel format (κ = 0.33) (P < .0001 and P = .0085, respectively). CONCLUSION: When images are well registered, subtraction and color-encoded subtraction techniques offer advantages over the traditional parallel presentation format for the assessment of SI differences.