Diagnostics of infrapatellar saphenous neuralgia-a reversible cause of chronic anteromedial pain following knee surgery.

OBJECTIVES: To evaluate the impact of diagnostic nerve block and ultrasound findings on therapeutic choices and predict the outcome after concomitant surgery in patients with suspected neuropathy of the infrapatellar branch of the saphenous nerve (IPBSN). METHODS: Fifty-five patients following knee surgery with suspicion of IPBSN neuralgia were retrospectively included. Ultrasound reports were assessed for neuroma and postsurgical scarring (yes/no). Responders and non-responders were assigned following anesthetic injection of the IPBSN. The type of procedure (neurectomy/interventional pain procedure/other than nerve-associated therapy) and pain score at initial follow-up were recorded and patients were assigned as positive (full pain relief) or negative (partial/no pain relief) to therapeutic nerve treatment. Factors associated with a relevant visual analog scale (VAS) reduction were assessed using uni- and multivariate logistic regression models and chi-square for quantitative and qualitative variables (p ≤ 0.05). RESULTS: Responders (37/55) more often had an entrapment or an evident neuroma of the IPBSN (97% vs. 6%). A positive Hoffmann-Tinel sign (p = 0.002) and the absence of knee joint instability (p = 0.029) predicted a positive response of the diagnostic nerve block (90%; 26/29). In the follow-up after therapeutic nerve treatment, all patients with full pain relief showed neuromas or entrapment of the IPBSN. Patients negatively responding to therapeutic nerve treatment more frequently showed an additional knee joint instability (25% vs. 4%). CONCLUSION: Selective denervation for neuropathic knee pain is beneficial in selected patients with significant VAS reduction after diagnostic nerve block. Non-responders following diagnostic nerve block but sonographic evidence of IPBSN pathologies need to be evaluated for other causes such as knee joint instability. KEY POINTS: • Sonographic diagnosis of neuroma or entrapment of the IPBSN is frequently seen in patients with anteromedial knee pain and leads to a good response to diagnostic nerve block following knee surgery. • The vast majority of patients with clinical signs of IPBSN neuropathy and response to a diagnostic nerve block sustained full pain relief following therapeutic nerve treatment. • Patients not responding to therapeutic IPBSN treatment have to be evaluated for other causes of anteromedial knee pain such as knee joint instability.

MR relaxometry of the liver: significant elevation of T1 relaxation time in patients with liver cirrhosis.

OBJECTIVES: To evaluate hepatic relaxation times T1, T2 and T2* in healthy subjects and patients with liver cirrhosis stratified by the Child-Pugh classification (CPC). METHODS: Sixty-one consecutive patients were stratified by CPC (class A026; B020; C015) and compared with age-matched controls (n = 31). Relaxometry measurements were performed at 1.5 T using six saturation recovery times (200-3,000 ms) to determine liver T1, six echo times (TE 14-113 ms) for T2 and eight TE (4.8-38 ms) for T2* assessment. Signal intensities in selected regions of interest in the liver parenchyma were fitted to theoretical models with least squares minimisation algorithms to determine T1, T2 and T2*. RESULTS: The most significant difference was the higher T1 values (852 ± 132 ms) in cirrhotic livers compared with controls (678 ± 45 ms, P < 0.0001). A less significant difference was seen for T2* (23 ± 5 vs. 26 ± 7 ms). Subdifferentiation showed a statistically significant difference between control group and individual CPC classes as well as between class C and classes A or B for T1 relaxation times. CONCLUSION: Measurement of T1 relaxation time can differentiate healthy subjects from patients with liver cirrhosis, and can distinguish between mild/moderate disease (CPC A/B) and advanced disease (CPC C). KEY POINTS: • Significantly elevated magnetic resonance T1 relaxation times are found in liver cirrhosis. • T1 relaxation times can distinguish healthy subjects from patients with liver cirrhosis. • T1 relaxation times can distinguish Child-Pugh classes Aand B from C.

Dose-optimized computed tomography of the cervical spine in patients with shoulder pull-down: Is image quality comparable with a standard dose protocol in an emergency setting?

PURPOSE: Superimposing soft tissue and bony structures in computed tomography (CT) of the cervical spine (C-spine) is a limiting factor in optimizing radiation exposure maintaining an acceptable image quality. Therefore, we assessed image quality of dose-optimized (DO) C-spine CT in patients capable of shoulder pull-down in an emergency setting. METHODS AND MATERIALS: DO-CT (105mAs/120 kVp) of the C-spine in trauma settings was performed in patients with shoulder pull-down if C5 was not superimposed by soft tissue on the lateral topogram, otherwise standard-dose (SD)-CT (195 mAs/120 kVp) was performed. 34 DO (mean age, 68y ±â€¯21; BMI, 24.2 kg/m2 ±â€¯3.2) and 34 SD (mean age 70y ±â€¯19; BMI 25.7 kg/m2 ±â€¯4.4) iterative reconstructed CTs were evaluated at C2/3 and C6/7 by two musculoskeletal radiologists. Qualitative image noise and morphological characteristics of bony structures (cortex, trabeculae) were assessed on a Likert scale. Quantitative image noise was measured and effective dose (ED) was recorded. Parameters were compared using Mann-Whitney-U-test (p < 0.05). RESULTS: At C2/3, DO-CT vs. SD-CT yielded comparable qualitative noise (mean, 1.3 vs. 1.0; p = 0.18) and morphological characteristics, but higher quantitative noise (27.2 ±â€¯8.8HU vs. 19.6 ±â€¯4.5HU; p < 0.001). At C6/7, DO-CT yielded lower subjective noise (1.9; SD-CT 2.2; p = 0.017) and better morphological characteristics with higher visibility scores for cortex (p = 0.001) and trabeculae (p = 0.03). Quantitative noise did not differ (p = 0.24). Radiation dose was 51% lower using DO-CT (EDDO-CT 0.80 ±â€¯0.1 mSv; EDSD-CT 1.63 ±â€¯0.2 mSv; p < 0.001). CONCLUSION: C-spine CT with dose reduction of 51% showed no image quality impairment. Additional pull-down of both shoulders allowed better image quality at lower C-spine segments as compared to a standard protocol.