Imaging features in management of laparoscopic mini/one anastomosis gastric bypass post-surgical complications

Obesity is a widespread pathology among the population related to an increase in mortality and morbidity of patients. Bariatric surgery provides several forms of treatment for obese patients. Laparoscopic mini/one anastomosis gastric bypass (MGB/OAGB) is a recent low risk bariatric surgical procedure common in a large number of countries in the treatment of severe obesity. MGB/OAGB, compared to other bariatric surgery techniques, offers the significant technical improvement of requiring only one anastomosis in place of two. In this scenario, diagnostic imaging takes a significant role in the postoperative period, to evaluate the outcomes of surgical treatment and to detect possible complications both in early and late postoperative period. The prevalent radiological procedure to investigate suspicions of clinical post-operative complications is Computed tomography (CT) with oral and intravenous contrast administration. This pictorial essay aims to illustrate and identify normal radiological aspects of MGB/OAGB and post-surgery complication imaging features. We think that this article will serve to familiarize all the specialists with the diagnostic imaging of MGB/OAGB.

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Laparoscopic mini/one anastomosis gastric bypass (MGB/OAGB) is a recent metabolic/bariatric surgery (MBS) technique that proved safe and valid for patients who were morbidly obese as a malabsorptive or metabolic gastric bypass.

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Diagnostic imaging takes a significant role in the postoperative period, to detect possible complications both in the early and late postoperative period.

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Water-soluble contrast upper gastrointestinal (UGI) series represent the first radiological modality in the detection of early postoperative complications.

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Computed tomography (CT) is a more frequently used imaging technique in the clinical suspicion of possible early and late postoperative complications.

Shear wave and strain sonoelastography for the evaluation of the Achilles tendon during isometric contractions

Objectives

Changes in mechanical loading as well as pathology can modify the Achilles tendon mechanical properties and therefore detection of these changes is relevant for the diagnosis and management of Achilles tendinopathy. The aim of this study was to evaluate strain and shear wave sonoelastography for their ability to detect changes in the Achilles tendon mechanical properties during a series of isometric contractions.

Methods

Longitudinal sonoelastography images of the Achilles tendon were acquired from 20 healthy participants using four different ultrasound devices; two implementing strain sonoelastography technology (SE1, SE2) and two, shear wave elastography technology (SWE1, SWE2).

Results

SE1 measured a decreasing strain ratio (tendon become harder) during the different contraction levels from 1.51 (0.92) to 0.33 (0.16) whereas SE2 mesaured a decreasing strain ratio from 1.08 (0.76) to 0.50 (0.32). SWE1 measured decreasing tendon stiffness during contractions of increasing intensity from 33.40 (19.61) to 16.19 (2.68) whereas SWE2 revealed increasing tendon stiffness between the first two contraction levels from 428.65 (131.5) kPa to 487.9 (121.5) kPa followed by decreasing stiffness for the higher contraction levels from 459.35 (113.48) kPa to 293.5 (91.18) kPa.

Conclusions

Strain elastography used with a reference material was able to detect elasticity changes between the different contraction levels whereas shear wave elastography was less able to detect changes in Achilles tendon stiffness when under load. Inconsistent results between the two technologies should be further investigated.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13244-021-00974-y.

Correlation of the tumour-stroma ratio with diffusion weighted MRI in rectal cancer

OBJECTIVE

This study evaluated the correlation between intratumoural stroma proportion, expressed as tumour-stroma ratio (TSR), and apparent diffusion coefficient (ADC) values in patients with rectal cancer.

METHODS

This multicentre retrospective study included all consecutive patients with rectal cancer, diagnostically confirmed by biopsy and MRI. The training cohort (LUMC, Netherlands) included 33 patients and the validation cohort (VHIO, Spain) 69 patients. Two observers measured the mean and minimum ADCs based on single-slice and whole-volume segmentations. The TSR was determined on diagnostic haematoxylin & eosin stained slides of rectal tumour biopsies. The correlation between TSR and ADC was assessed by Spearman correlation (r_s).

RESULTS

The ADC values between stroma-low and stroma-high tumours were not significantly different. Intra-class correlation (ICC) demonstrated a good level of agreement for the ADC measurements, ranging from 0.84-0.86 for single slice and 0.86-0.90 for the whole-volume protocol. No correlation was observed between the TSR and ADC values, with ADC_meanr_s= -0.162 (p= 0.38) and ADC_minr_s= 0.041 (p= 0.82) for the single-slice and r_s= -0.108 (p= 0.55) and r_s= 0.019 (p= 0.92) for the whole-volume measurements in the training cohort, respectively. Results from the validation cohort were consistent; ADC_meanr_s= -0.022 (p= 0.86) and ADC_minr_s = 0.049 (p= 0.69) for the single-slice and r_s= -0.064 (p= 0.59) and r_s= -0.063 (p= 0.61) for the whole-volume measurements.

CONCLUSIONS

Reproducibility of ADC values is good. Despite positive reports on the correlation between TSR and ADC values in other tumours, this could not be confirmed for rectal cancer.

Laparoscopic mini/one anastomosis gastric bypass: anatomic features, imaging, efficacy and postoperative complications

Laparoscopic mini/one anastomosis gastric bypass (MGB/OAGB) is an increasingly used bariatric surgical procedure. This surgical technique is effective in terms of both weight loss and the resolution of comorbidities, but it is not without complications. To report our experience in MGB/OAGB, assessing comorbidities and complications, and to illustrate post-surgical anatomy and radiological appearance of complications, a single-centre retrospective study of 953 patients undergoing MGB/OAGB between January 2005 and September 2018 was done. The inclusion criteria: body mass index (BMI) of 40 kg/m² or higher or BMI between 35 and 40 kg/m² with significant comorbidities not responsive to medical therapies. In the postoperative period, all patients were evaluated with clinical and laboratory tests and radiological examinations (upper gastrointestinal series, computed tomography and magnetic resonance imaging). Median weight was 126.69 kg and mean BMI was 49.4 kg/m². Regarding comorbidities, 37.2%, 52.8%, 46.7% and 43.2% of patients presented with preoperatively diagnosed type 2 diabetes mellitus (T2DM), hypertensive disease, dyslipidaemia and obstructive sleep apnoea syndrome (OSAS), respectively. Median excess weight loss at 6, 12, 24 and 60 months after surgery was 33.45%, 53.81%, 68.75% and 68.80%, respectively. The remission of comorbidities was 91.4% for T2DM, 93.7% for hypertensive disease, 90.3% for dyslipidemia and 93.4% for OSAS. Early and late complication rates identified with radiological examinations were 1.5% and 1.6%, respectively. MGB/OAGB was effective for weight loss and comorbidities remission. Complications occurred at lower rate than with other surgical procedures were identified with imaging; CT was the main radiological technique.

A proposal for a semiquantitative scoring system for lymphedema using Non-contrast Magnetic Resonance Lymphography (NMRL): Reproducibility among readers and correlation with clinical grading

PURPOSE

To assess the ability and reproducibility of Non-contrast Magnetic Resonance Lymphography (NMRL) in detecting and quantify lymphedema, using a semiquantitative scoring system.

METHODS AND MATERIAL

This is a monocentric retrospective study of 134 consecutive patients with a clinical diagnosis of limb lymphedema who performed a Non-contrast Magnetic Resonance Lymphography (NMRL) at our Institution between November 2014 and February 2017. Lymphedema was classified based both on clinical and radiologic evaluation. An NMRL total score was obtained for each limb's segment and compared to the clinical grade, used as reference standard. NMRL intra-observer, inter-observer variability and intraclass correlation were calculated. NMRL sensitivity, specificity, and accuracy in identifying lymphedema were provided. Based on score distribution an NMRL four-stage system was developed.

RESULTS

NMRL showed 92% sensitivity, 77% specificity and 82% accuracy in identifying lymphedema. An almost perfect agreement was obtained by expert operators, while substantial agreement was obtained by non-expert operators. Substantial agreement resulted also for the inter-observer variability (Cohen's Kappa K = 0.73, CI 95% [0.69-0.78]). The intra-class correlation showed an almost perfect relationship both by expert and non-expert operators. Excellent correlation between clinical grade and NMRL score and between clinical grade and NMRL stage were found for each segment.

CONCLUSIONS

NMRL is a confident and reproducible exam with high sensitivity, good specificity and high accuracy in lymphedema detection; the semiquantitative NMRL score resulted a reliable and reproducible tool able to quantify lymphedema severity.

Eagle's syndrome: a case report and CT pictorial review

Eagle's syndrome (ES) refers to symptomatic elongation of the ossified styloid process. A styloid process greater than 2.5 cm in length should be considered abnormal; however, an elongated styloid process is not sufficient for a diagnosis of ES; only an abnormal styloid process in association with symptoms can confirm the syndrome. In this case report, we discuss a 54-year-old man who has come to our attention with various symptoms: dysphagia to both solids and liquids, difficulty swallowing, neck pain, and a foreign body sensation during bilateral neck rotation and mouth opening. The diagnosis is performed radiologically because conventional radiographs have many potential disadvantages, whereas, computed tomography (CT) scans and reconstructions allow the length and angulation of the styloid process to be measured and the relationship between the elongated styloid processes and adjacent anatomical structures to be evaluated. Moreover, CT allows for differential diagnosis and provides detailed information needed for surgical planning.

High-Frame Rate Vector Flow Imaging of the Carotid Bifurcation in Healthy Adults: Comparison With Color Doppler Imaging

OBJECTIVES

To evaluate the carotid bifurcation in healthy adults using a commercial system equipped with high-frame rate vector flow imaging (VFI) based on the plane wave and to compare VFI with color Doppler imaging.

METHODS

Carotid bifurcation diameters and flow characteristics of 60 vessels in 60 healthy volunteers were evaluated quantitatively and qualitatively to assess complex flow patterns and their extension and duration.

RESULTS

Complex flow in the internal carotid artery (ICA) was associated with a statistically significant difference in the ΔICA sinus-to-common carotid artery (CCA) diameter ratio (the relative change in diameter between the CCA and ICA sinus.) Vector flow imaging and color Doppler imaging were in accordance when detecting complex flow in 96.7% of cases; in 3.3% of cases, only VFI identified small recirculation areas of short duration. Vector flow imaging highlighted a larger extension of the complex flow (mean ± SD, 47.7 ± 28.5 mm² ; median, 45.5 mm² ) compared with color Doppler imaging (mean, 29.2 ± 19.9 mm² ; median, 29.5 mm² ) and better depicted different complex flow patterns; a strong correlation (r = 0.84) was found between the ΔICA sinus-to-CCA diameter ratio and the complex flow extension. Vector flow imaging showed a longer duration of the flow disturbances (mean, 380 ± 218 milliseconds; median, 352.5 milliseconds) compared with color Doppler imaging (mean, 325 ± 206 milliseconds; median, 333 milliseconds), and there was a strong correlation (r = 0.92).

CONCLUSIONS

Vector flow imaging is as effective as color Doppler imaging in the detection of flow disturbances, but it is more powerful in the assessment of complex flow patterns.

Median nerve evaluation by shear wave elastosonography: impact of "bone-proximity" hardening artifacts and inter-observer agreement

Purpose

Peripheral nerves frequently travel close to the bone surface and are, therefore, prone to elastosonographic "bone-proximity" hardening artifacts. The impact of these artifacts on quantitative measurements of median nerve stiffness performed by shear wave elastosonography has not been explored. Our aim was to assess normal median nerve stiffness values at various locations.

Materials and methods

Thirty-six healthy volunteers (24 women and 12 men) aged between 25 and 40 years were evaluated. Two operators performed the evaluation: one expert (6 years of ultrasound experience) and one inexperienced operator (6 months' experience). The nerve was sampled in cross-section at three different locations: mid-forearm, immediately before the carpal tunnel and within the tunnel. The ultrasound scanner was equipped with a 14-MHz linear probe. The Shear Wave module was activated in one-shot mode. Measurements were performed using a ROI corresponding to the diameter of the nerve.

Results

The mean values of stiffness of the medial nerve were 32.26 kPa ± 18.60 within the carpal tunnel, 22.20 kPa ± 9.84 at the carpal tunnel inlet and 7.62 kPa ± 7.38 in the forearm. Inter-observer agreement assessed using the intraclass correlation coefficient (ICC) was "moderate" within the carpal tunnel (ICC = 0.44), "moderate" at the carpal tunnel inlet (ICC = 0.41) and "fair" in the forearm (ICC = 0.38).

Conclusions

The stiffness of the median nerve progressively increases in its distal portions, where the nerve approaches the bone surface. Inter-observer agreement was generally good (from fair to moderate).

Vector flow imaging techniques: An innovative ultrasonographic technique for the study of blood flow

Doppler ultrasonography is routinely used to identify abnormal blood flow. Nevertheless, conventional Doppler can be used to determine only the axial component of blood flow velocity and is angle dependent. A new method of multidimensional angle-independent estimation of flow velocity, called Vector Flow Imaging (VFI), has been proposed. It quantitatively evaluates the true velocity vector's amplitude and direction at any location into a vessel and displays a more intuitive depiction of the flow movements. High frame rate VFI, based on plane wave imaging, allows a detailed dynamic visualization of complex flow by showing even transient events, otherwise undetectable. © 2017 Wiley Periodicals, Inc. J Clin Ultrasound 45:582-588, 2017.