Ultrasonographic Detective Flow Imaging for Evaluating Parathyroid Adenoma in Patients with Primary Hyperparathyroidism.

BACKGROUND: Detective flow imaging (DFI) is a new imaging technology that displays low-velocity blood flow, which is difficult to visualize on conventional color Doppler ultrasonography (CDU). In this study, we compared the usefulness of DFI with that of CDU and methoxy-isobutyl-isonitrile (MIBI) scintigraphy for detecting parathyroid adenoma (PA) in patients with primary hyperparathyroidism (PHPT). METHODS: From March 2021 to March 2023, 87 PHPT patients underwent surgery, and 66 had a single PA. We performed preoperative conventional ultrasonography with CDU, MIBI scintigraphy, and DFI for 42 patients (5 males and 37 females; mean age: 61.6 ± 15.4 years). RESULTS: MIBI scintigraphy detected PA in 85.7% (36/42) patients, and both CDU and DFI detected PA in all patients. The rates of vascularity in PA detected by CDU and DFI were 71.4% (30/42) and 85.7% (36/42), respectively. Vascularity was detected by DFI in 6 patients who were negative for vascularity on MIBI scintigraphy. Furthermore, DFI detected blood supply in 6 of the 12 patients with undetectable blood supply on CDU. Fisher's exact test revealed that high or low blood flow, as determined by DFI, was significantly associated with detection of feeding vessels in PA by CDU (P < 0.001). CONCLUSIONS: DFI was useful for preoperative detection of PA blood flow.

Deep-learning-based sampling position selection on color Doppler sonography images during renal artery ultrasound scanning.

Accurate selection of sampling positions is critical in renal artery ultrasound examinations, and the potential of utilizing deep learning (DL) for assisting in this selection has not been previously evaluated. This study aimed to evaluate the effectiveness of DL object detection technology applied to color Doppler sonography (CDS) images in assisting sampling position selection. A total of 2004 patients who underwent renal artery ultrasound examinations were included in the study. CDS images from these patients were categorized into four groups based on the scanning position: abdominal aorta (AO), normal renal artery (NRA), renal artery stenosis (RAS), and intrarenal interlobular artery (IRA). Seven object detection models, including three two-stage models (Faster R-CNN, Cascade R-CNN, and Double Head R-CNN) and four one-stage models (RetinaNet, YOLOv3, FoveaBox, and Deformable DETR), were trained to predict the sampling position, and their predictive accuracies were compared. The Double Head R-CNN model exhibited significantly higher average accuracies on both parameter optimization and validation datasets (89.3 ± 0.6% and 88.5 ± 0.3%, respectively) compared to other methods. On clinical validation data, the predictive accuracies of the Double Head R-CNN model for all four types of images were significantly higher than those of the other methods. The DL object detection model shows promise in assisting inexperienced physicians in improving the accuracy of sampling position selection during renal artery ultrasound examinations.

Ultrasound features of high-risk basal cell carcinoma: a systematic review.

Basal Cell Carcinoma (BCC) is the most prevalent skin cancer and continues to witness a surge in incidence rates. The categorization of BCC subtypes into low or high risk, guided by recurrence and invasiveness metrics, underscores the need for precise differentiation. While the punch biopsy remains the gold standard for diagnosis, its invasiveness prompts a need for non-invasive alternatives. Ultrasound (US) has emerged as a noteworthy candidate, gaining momentum in its potential to offer a less intrusive diagnostic approach. We conducted a systematic review regarding features of the high-risk subtypes of BCC on US. A thorough literature search of PubMed Medline, Embase, and CINAHL databases was conducted according to PRISMA guidelines and a total of nine studies meeting our inclusion criteria were included in this review. Evidence is still nascent but US features such as lesional shape, depth, hyperechoic spots, and color doppler may be helpful in differentiating high-risk BCC subtypes. However, further prospective studies with standardized interventions and outcome measures are required.

Use superb microvascular imaging to diagnose and predict metastatic cervical lymph nodes in patients with papillary thyroid carcinoma.

PURPOSE: Papillary thyroid carcinoma (PTC) with metastatic lymph nodes (LNs) is closely associated with disease recurrence. This study accessed the value of superb microvascular imaging (SMI) in the diagnosis and prediction of metastatic cervical LNs in patients with PTC. METHODS: A total of 183 cervical LNs (103 metastatic and 80 reactive) from 116 patients with PTC were analysed. Metastatic cervical LNs were confirmed by pathology or/and cytology; reactive cervical LNs were confirmed by pathology or clinical features. The characteristic of conventional ultrasound (US) was extracted using univariate and multivariate analyses. The diagnostic performance of US and SMI were compared using the area under the receiver operating curve (AUC) with corresponding sensitivity and specificity. A nomogram was developed to predict metastatic LNs in patients with PTC, based on multivariate analyses. RESULTS: L/S < 2, ill-defined border, absence of hilum, isoechoic or hyperechoic, heterogeneous internal echo, peripheral or mixed vascular pattern on color Doppler flow imaging (CDFI) and SMI, and a larger SMI vascular index appeared more frequently in metastatic LNs in the training datasets than in reactive LNs (P < 0.05). The diagnostic sensitivity, specificity and accuracy of SMI vs US are 94.4% and 87.3%, 79.3% and 69.3%, and 87.6% and 79.1%, respectively; SMI combined with US exhibited a higher AUC [0.926 (0.877-0.975)] than US only [0.829 (0.759-0.900)]. L/S < 2, peripheral or mixed vascular type on CDFI, and peripheral or mixed vascular types on SMI were independent predictors of metastatic LNs with PTC. The nomogram based on these three parameters exhibited excellent discrimination, with an AUC of 0.926. CONCLUSION: SMI was superior to US in diagnosing metastatic LNs in PTC. US combined with SMI significantly improved the diagnostic accuracy of metastatic cervical LNs with PTC. SMI is efficacious for differentiating and predicting metastatic cervical LNs.

[Analysis on the ultrasonic characteristics of tonsillar lymphoma].

Objective: To analyze the ultrasonic features of tonsillar lymphoma to improve the diagnostic accuracy. Methods: The clinical, pathological and ultrasonic data of nine patients with tonsillar lymphoma confirmed by pathology at Tianjin Medical University Cancer Institute and Hospital during June 2015 and June 2022 were analyzed retrospectively, and the characteristics of their ultrasonic images were summarized. Results: All 9 cases of tonsil lymphoma were unilateral tonsil disease, including 4 cases on the left side and 5 cases on the right side. The average maximum diameter of tonsil lymphoma in 9 cases was 4.32 cm. There were 3 cases with simultaneous involvement of tonsil and cervical lymph nodes, all of which were ipsilateral lymph nodes. Gray scale ultrasound showed that the lesions were hypoechoic, with clear boundaries in 7 cases and unclear boundaries in 2 cases. The shape was full and irregular in 5 cases and oval in 4 cases. The echo was uniform in 7 cases and uneven in 2 cases. Color Doppler ultrasonography showed abundant internal blood flow signal in 1 case, a little dotted linear internal blood flow signal in 5 cases, and no obvious internal blood flow signal in 3 cases. Conclusions: The ultrasonic features of tonsillar lymphoma include hypoechoic area, clear boundary, full shape, irregular and uniform internal echo, no or low linear signal of internal blood flow. Ultrasonography is of great value in the diagnosis of this disease and can help clinical decision-making.

Evaluation and clinical significance of contrast-enhanced ultrasound on changes in liver blood flow perfusion after TIPS surgery.

To investigate the clinical value of contrast-enhanced ultrasound in the prediction of hepatic encephalopathy (HE) in patients with hepatitis B cirrhosis after intrahepatic portal-systemic shunt via jugular vein. In this retrospective study, we collected data from 75 patients with hepatitis B, cirrhosis, and portal hypertension who underwent jugular intrahepatic portosystemic shunt from February 2019 to February 2022. The diagnostic instrument used was the TOSHIBA Aplio500 color Doppler ultrasound with contrast-enhanced ultrasound capabilities. The trial group comprised 20 patients with HE within 3 months postsurgery, while the control group (CG) included 55 patients without HE within the same postoperative period. All patients underwent various examinations before and within 48 hours after surgery, including observation of liver and spleen size and stent position, as well as assessment of blood flow direction in portal and hepatic veins. Subsequently, contrast-enhanced ultrasound was employed to examine and observe perfusion changes of contrast agents in hepatic veins, hepatic arteries, and portal veins (PV). Changes in PV pressure gradient, intrahepatic, and stent blood flow perfusion (BFP) were explored in both postoperative trials and CGs. The trial group exhibited higher BFP volume, PV pressure gradient difference, and percentage decrease compared to the CG. A weak positive correlation was observed between blood flow within the liver stent and PV pressure gradient difference, as well as the percentage decrease in PV pressure gradient. The correlation coefficient between blood flowing perfusion volume within the stent and the difference in PV pressure gradient was R = 0.415 (P = .000). The correlating coefficient between BFP amount within the stent and the percentage decrease in PV pressure gradient was R = 0.261 (P = .027). The area under the receiver operating characteristic curve for stent perfusion volume, difference in PV pressure gradient, and percentage decrease in PV pressure gradient was 0.691, 0.759, and 0.742, respectively. An increase in PV pressure gradient accelerates blood flow within the stent, predisposing to HE. Changes in hepatic BFP following transjugular intrahepatic portosystemic shunt can effectively predict the occurrence of HE, demonstrating significant clinical relevance.

Non-mass-type ductal carcinoma in situ of the breast on ultrasound: Features and pathological analysis.

AIMS: The aims of this study were to investigate the ultrasound features of non-mass-type ductal carcinoma in situ (DCIS) of the breast and conduct a pathological analysis. MATERIAL AND METHODS: Ultrasound images of 32 cases of non-mass-type DCIS of the breast, collected between September 2014 and June 2016, were analyzed. The characteristics of the lesions, including border, internal echogenicity, local glandular hyperplasia, micro-calcification, and intra-tumoral blood flow resistance index (RI), were analyzed, and a concurrent pathological analysis was conducted. RESULTS: Obvious local glandular hyperplasia was commonly observed in the 32 cases of non-mass-type DCIS of the breast. The internal echogenicity varied in intensity, exhibiting a "leopard pattern" or "zebra pattern." Color Doppler imaging revealed abundant blood flow signals within the lesion with an RI of >0.7. Isolated duct dilatation and micro-calcifications were occasionally observed within the lesions. High-grade DCIS was the predominant pathological type of non-mass-type DCIS. CONCLUSIONS: Non-mass-type DCIS of the breast often presents with obvious local glandular hyperplasia and varying internal echogenicity. High-grade DCIS is the frequent pathological type. Color Doppler imaging and RI measurement can assist in diagnosing non-mass-type DCIS of the breast.

[Cutting scheme and clinical application effects of ultrathin thoracodorsal artery perforator flap assisted by color Doppler ultrasound].

Objective: To explore the cutting scheme and clinical application effects of ultrathin thoracodorsal artery perforator flap assisted by color Doppler ultrasound. Methods: This study was a retrospective historical control study. From February 2017 to October 2019, 20 patients who were admitted to the Third Department of Orthopedics of Xingtai General Hospital of North China Medical and Health Group (hereinafter referred to as our department), met the inclusion criteria, and underwent repair of skin and soft tissue defects of extremities with ultrathin thoracodorsal artery perforator flap designed and harvested based on the surgeon's clinical experience were selected as control group, including 16 males and 4 females, aged (37±5) years. From November 2019 to December 2022, 21 patients who were admitted to our department, met the inclusion criteria, and underwent repair of skin and soft tissue defects of extremities with ultrathin thoracodorsal artery perforator flap designed and harvested under the assistance of color Doppler ultrasound were selected as ultrasound-assisted group, including 15 males and 6 females, aged (38±6) years. After debridement, the area of skin and soft tissue defects of extremities ranged 5.0 cm×4.0 cm to 19.0 cm×8.0 cm, and the area of thoracodorsal artery perforator flaps ranged 6.0 cm×5.0 cm to 20.0 cm×9.0 cm. The wounds in flap donor sites were closed directly. For patients in ultrasound-assisted group, the time and cost required for color Doppler ultrasound examination were recorded, and the number, type, and location of thoracodorsal artery perforator vessels detected by preoperative color Doppler ultrasound were compared with those of intraoperative actual detection. The time required for complete flap harvest of patients in 2 groups was recorded. On postoperative day (POD) 1, 3, 5, 7, and 14, the blood perfusion of flaps in the 2 groups of patients was assessed using a flap perfusion assessment scale. On POD 14, flap survival of patients in 2 groups was observed, and the percentage of flap survival area was calculated. In postoperative 6 months, satisfaction of patients with the treatment outcome in the 2 groups was assessed using 5-grade Likert scale, and the satisfaction rate was calculated. Results: For patients in ultrasound-assisted group, the time required for preoperative color Doppler ultrasound examination was (10.5±2.3) min, and the cost was 120 yuan; 21 thoracodorsal artery perforator vessels were detected and marked using preoperative color Doppler ultrasound, including 8 (38.10%) type 1 perforator vessels, 10 (47.62%) type 2 perforator vessels, and 3 (14.29%) type 3 perforator vessels; the number, type, and location of thoracodorsal artery perforator vessels detected preoperatively were consistent with those detected intraoperatively. The time required for complete flap harvest of patients in ultrasound-assisted group was (41±10) min, which was significantly shorter than (63±12) min in control group (t=6.32, P<0.05). On POD 1, 3, 5, 7, and 14, the blood perfusion scores of flaps of patients in ultrasound-assisted group were significantly better than those in control group (with t values of 6.67, 7.48, 8.03, 8.75, and 7.99, respectively P<0.05). On POD 14, only one patient in ultrasound-assisted group had partial flap necrosis and 6 patients in control group had complete or partial necrosis of the flap; the percentage of flap survival area of patients in ultrasound-assisted group was (99±8)%, which was significantly higher than (87±8)% in control group (t=4.57, P<0.05). In postoperative 6 months, there was no significant difference in the satisfaction rate of patients with the treatment outcome between the two groups (P>0.05). Conclusions: Preoperative color Doppler ultrasound is highly accurate in detecting the number, type, and location of perforator vessels. The cutting scheme of ultrathin thoracodorsal artery perforator flaps can be designed according to the different types of perforator vessels, with shorted flap cutting time and improved flap survival rate.

Transcranial sonography in the critical patient.

Transcranial ultrasonography is a non-invasive, bedside technique that has become a widely implemented tool in the evaluation and management of neurocritically ill patients. It constitutes a technique in continuous growth whose fundamentals (and limitations) must be known by the intensivist. This review provides a practical approach for the intensivist, including the different sonographic windows and planes of insonation and its role in different conditions of the neurocritical patients and in critical care patients of other etiologies.

A Pilot Study on Novel Use of Color Doppler Imaging for Navigation of Wiring in Coronary Interventions.

OBJECTIVE: To test the Doppler guide wire (DGW) for navigation of the wire positioning by color Doppler ultrasound in the setting of percutaneous coronary intervention (PCI). METHODS: An acoustically active DGW was tested in a water tank before its in vivo use. A waveform generator was connected to the DGW, and a transducer scanned the DGW to visualize a Doppler shift signal between the vibrating piezoelectric crystal located at the DGW tip and Doppler signal from the transducer as a distinct, instantaneous color marker. An intracoronary injection was tested in four male domestic pigs using an open-chest setting. A Judkins left coronary guiding catheter was inserted into the ascending aorta via the right carotid artery under B-mode ultrasound guidance. The DGW with an infusion catheter or over-the-wire (OTW) balloon catheter was inserted into the guiding catheter. The color marker instantaneously defined the DGW tip and navigated the catheter into the left anterior descending artery (LAD). RESULTS: The tip of the DGW was visualized within the guiding catheter by a distinct color marker and helped to engage the guiding catheter to the left main orifice. The DGW with an infusion or OTW balloon catheter was inserted into the LAD. We confirmed that the catheter was positioned in the proximal LAD by the colored territory perfused by an injected indigo carmine solution. CONCLUSION: Ultrasound navigation using acoustically active DGW was feasible. Our pilot study introduces a new concept of color Doppler-navigated wire positioning in the coronary artery in the setting of PCI.

Evaluation of submandibular and parotid salivary glands by ultrasonography in patients with diabetes.

BACKGROUND: Microvascular complications of diabetes mellitus (DM) include oral manifestations and complications, including xerostomia, reduced salivary flow, susceptibility to infection, periodontal disease and salivary gland enlargement. OBJECTIVE: The present study aims to evaluate B-mode ultrasonography (USG) parameters such as size, volume and echogenicity of the submandibular and parotid salivary glands on both sides, shear-wave elastography (SWE) value and colour Doppler properties in patients with DM and healthy control groups. METHODS: In total, 160 right and left submandibular glands and 160 right and left parotid glands of 80 patients, 40 patients (20 type 1 DM, 20 type 2 DM) and 40 healthy control group, between the ages of 18-70 were examined by USG. Echogenicity, parenchyma internal structure, margin and dimensional measurements (antero-posterior length, supero-inferior length, medio-lateral length and volume) and colour Doppler with 'ML 6-15-D Matrix Array (4-15 MHz)' probe, shear-wave elastography '9L-D (2-8 MHz)' probe was investigated. RESULT: Statistically significant difference was observed in echogenicity in the right submandibular gland, echogenicity in the right parotid gland, margin characteristics, parenchymal homogeneity and colour Doppler characteristics between the type 1 DM, type 2 DM and control groups (p < .05). It was observed that the size, volume and SWE values of both submandibular and parotid glands were higher in the DM patient group than in the control group. Higher values were observed in type 2 DM compared to type 1 DM in the patient group. CONCLUSION: USG is an effective imaging technique in investigating the effects of diabetes on the submandibular and parotid salivary glands.

Color Doppler Ultrasound Indices as Predictors of Propranolol Response in Infantile Hemangioma: A Prospective Study.

OBJECTIVE: To evaluate the utility of color Doppler ultrasonography in assessing infantile hemangioma response to treatment with oral propranolol. METHODS: A prospective study was conducted between January, 2016 and December, 2022, wherein children with symptomatic (ulceration, bleeding, pain and scarring) infantile hemangioma were given oral propranol (2 mg/kg per day in three divided doses) as outpatient therapy. The clinical response was assessed three months post-initiation of treatment (intermediate clinical response) and three months post-completion of treatment (final clinical response, FCR). The primary outcome measurement was a clinical and radiological response (resistivity index (RI), pulsatility index (PI) and peak systolic velocity) to treatment. The secondary outcomes assessed were the complications related to treatment. RESULTS: Out of 601 patients who were started on propranolol, 99 developed severe adverse effects and were excluded from analysis. At FCR assessment, out of 502 participants, 64.3% (n = 323) showed excellent response, 17.7% (n = 89) showed partial, and 17.9% (n = 90) were non-responders. A significant increase in RI and PI values was noted in all children following propranolol treatment for six months. An increase > 7.5% in RI could identify responders with 92% sensitivity, 91% specificity and area under the curve (AUC) of 0.963. An increase of > 11.5% in PI could identify responders with 86% sensitivity, 91% specificity and AUC of 0.896. Patients initially showing no response but later becoming excellent responders had significantly higher RI and PI values. CONCLUSIONS: Color Doppler ultrasonography is a valuable tool in predicting the treatment outcome of infantile hemangioma using propranolol.

Superb Microvascular Imaging in Pediatric Focal Nodular Hyperplasia.

OBJECTIVE: To investigate superb microvascular imaging (SMI), a novel Doppler ultrasound technique that can visualize low-velocity microvascular flow, for assessing pediatric focal nodular hyperplasia (FNH). PATIENTS AND METHODS: Nine FNH lesions in 6 patients were enrolled. On SMI and color Doppler imaging (CDI), intralesional vascularity was assessed visually and categorized as typical spoke-wheel pattern (central vessel radiating from the center to the periphery), multifocal spoke-wheel pattern, and nonspecific pattern. We compared the vascular features of the lesions between SMI and CDI and evaluated vascular patterns according to lesion size. RESULTS: In terms of vascularity pattern, the typical spoke-wheel pattern of FNH was noted more frequently on SMI (67%) than on CDI (11%; P < 0.05). In addition, a multifocal spoke-wheel pattern was noted in all remaining lesions (33%) on SMI. On the contrary, a nonspecific vascular pattern was detected in the majority (78%) of CDI. Regarding the lesion size and vascularity on SMI, the typical spoke-wheel pattern was seen more frequently in the small FNH group than in the large FNH group. The intralesional vascular signal was detected more frequently on SMI (100%) than on CDI (89%). CONCLUSION: SMI is feasible in evaluating FNH in children and has a greater ability to demonstrate the spoke-wheel pattern than CDI.

Using 3-D-Printed Structures to Evaluate the Potential Causes of the Color Doppler Twinkling Signature.

OBJECTIVE: The color Doppler twinkling artifact has been attributed to existing microbubbles or cavitation occurring on rough objects such as kidney stones, some breast biopsy clips, catheter guidewires and sandpaper. The objective was to investigate the correlation between the surface characteristics of helical constructs with different groove geometries and the occurrence of twinkling, as well as to identify locations conducive to bubble retention and/or cavitation. METHODS: Six half-cylinders were created with a microscale 3-D printer with 5 µm resolution to replicate the geometry of twinkling helical constructs resembling catheter guidewires. Four copies of each marker including a non-twinkling control were printed. The half-cylinders had pitch (peak-to-peak distance) values ranging from 87.5 to 343 µm and amplitude (groove depth) values ranging from 41.5 to 209 µm. The half-cylinders were submerged in degassed water and optically imaged before and after ultrasound insonification to visualize bubbles on the cylinders. The cylinders remained submerged while scanning with the color Doppler mode at frequencies from 3.1 to 6.3 MHz using a GE Logiq E9 scanner and 9L linear array transducer. RESULTS: Two markers exhibited twinkling: one with pitch-to-amplitude ratio of 174/210 µm/µm (0.8) that twinkled only with pre-existing bubbles on the marker; the other had a ratio of 87/87 µm/µm (1.00) that twinkled without pre-existing bubbles on the marker. CONCLUSION: This work provides strong evidence that both existing bubbles and either cavitation or ultrasound wave interactions with patterned or rough surfaces are significant factors in producing the twinkling signature.

The value of multimodal ultrasonography in the evaluation of late presenting testicular torsion in a rat experimental model.

OBJECTIVE: To evaluate the value of multimodal ultrasonography (US) in a rat experimental torsion model after 6 h of torsion with different degrees. METHODS: Twenty-one male rats were divided into three groups. Left testes of the rats were twisted around their vascular pedicle 360 degrees in group 1, 720 degrees in group 2, and 1080 degrees in group 3 and intact right testes of the rats were accepted as control group. Grey-scale US, superb microvascular imaging (SMI), colour Doppler ultrasonography (CDUS), strain elastography (SE), and two-dimensional (2-D) shear wave elastography (SWE) examinations were applied 6 h after torsion procedure and testes were removed for pathological evaluation. RESULTS: Short-axis dimensions and volumes of the torsion side were higher than control testes. Lengths of the testes in the 3rd torsion group were smaller than the testes in groups 1 and 2 (P < 0.002). SMI was better than CDUS in recognizing blood flow in testicular tissue. Strain ratios were higher in group 1 and decreased with the increasing torsion degree. Emean and standard deviation (SD) measurements increased in the torsion side. Pathologically the mean testicular damage scores were statistically significant between torsion and control testes in all groups. CONCLUSION: Our results showed that short-axis and volume measurements, SMI, 2D-SWE, and SE are effective in the evaluation and diagnosis of testicular torsion (TT). ADVANCES IN KNOWLEDGE: Evaluation of affected testis and intact testis with multiparametric US in late presenting TT cases is more reliable than being dependent on a single sonographic modality.

Ultrasound diagnosis of Mondor's disease involving the superficial scrotal veins: Unveiling a rare mimicker of acute scrotal emergencies.

We describe a rare case of Mondor disease of the superficial scrotal veins, which can clinically mimic acute testicular pathologies such as testicular torsion or epididymo-orchitis, and highlight the value of grayscale/Doppler ultrasound examination in distinguishing these entities, which have different management implications.

[Application Research of Vector Flow Technique on Convex Array Ultrasonic Probe of Abdomen].

Vector flow imaging (VFI) is an innovative ultrasound flow measurement technology. Compared with the traditional color Doppler and spectral Doppler, VFI has the advantages of independence of angle correction and direct acquisition of real-time amplitude and direction of flow. Transverse oscillation (TO) method is one of the effective methods for vector flow imaging. However, a complete and detailed algorithm validation process based on commercial ultrasound machines is still lacking due to more complex convex probes. This study starts with introducing the imaging process and principle of transverse oscillation vector flow technique, and calculates the error between the set velocity value and the measured velocity value through the simulation experiment, and verifies the error between the set velocity value and the measured velocity value through the Doppler flow phantom experiment. Among them, the velocity value measured by the TO vector flow technique in the simulation experiment is 0.48 m/s and the preset value is 0.50 m/s, the error between them is -4%. The velocity values are 8.33, 11.14, 14.44 and 16.67 cm/s measured by the Doppler flow phantom experiment, the actual velocity values are 7.97, 10.78, 14.06 and 17.34 cm/s, the errors between them are all within ±5%. Both experiments verify the feasibility of using vector flow technique on abdominal convex probe.

Pre-operative colour Doppler ultrasound for the prevention of bleeding complications after renal biopsy: A rare case of left renal lower pole vein.

Albeit rare, renal vein abnormalities on autopsy and in cases of abdominal surgery complications have been reported and should be kept in mind when performing invasive procedures, such as renal biopsy. We detected a rare renal vein abnormality on colour Doppler ultrasound before renal biopsy, thereby, avoiding a haemorrhagic complication. A 10-year-old boy presented to our department for the first time because of incidental findings of haematuria and proteinuria. We suspected chronic glomerulonephritis and scheduled an ultrasound-guided percutaneous renal biopsy. A simple screening ultrasound at the initial visit revealed no renal or vascular abnormalities. The day before the renal biopsy, we confirmed the biopsy site by performing a colour Doppler ultrasound, which showed abnormal blood flow from the lower pole of the left kidney, which was the planned puncture site; therefore, we changed the biopsy site to the right and completed the examination. Subsequent computed tomography angiography depicted two renal veins; one was the usual left renal vein draining from the kidney hilum, and the second was an accessory vein draining from the inferior pole of the left kidney and entering the inferior vena cava through the dorsal side of the aorta. Although rare, abnormalities in the renal vessels on the inferior pole of the kidney, which is the usual site of renal biopsy, are essential to rule out preoperatively by colour Doppler ultrasound, because these can cause significant bleeding during renal biopsy if not recognized.