Successful Endovascular Management of Resistant Hypertension Post Kidney Transplant: A Case Report.

Rationale: Transplant renal artery stenosis (TRAS) is a well-recognized and potentially reversible cause of resistant hypertension post transplantation and can affect 1% to 23% of recipients. Stenosis of the iliac segment proximal to the transplant renal artery (proximal TRAS) causing dysfunction of the transplanted kidney is less common with reported incidence of 2% to 3%. Presentation typically occurs between 3 months and 2 years post transplant but may happen at any time. Noninvasive investigations such as Doppler ultrasound, computed tomography (CT) angiogram, and magnetic resonance angiogram are useful in initial evaluation, but definitive diagnosis of hemodynamically significant stenosis often requires formal angiogram. Transplant renal artery stenosis should be suspected in any kidney transplant recipient with worsening hypertension and/or deterioration in kidney function which is otherwise unexplained. We present the case of a kidney transplant recipient with resistant hypertension and impaired graft function, secondary to severe impairment of graft blood flow from proximal iliac system occlusion. Presenting concerns of the patient: A 74-year-old female 15 years post live donor kidney transplant presented with graft dysfunction (serum Cr 229 µmol/L) and resistant hypertension, requiring use of 8 antihypertensive medications. On physical examination, blood pressure was 160/92 mm Hg with no tenderness over the renal graft in the right lower abdominal quadrant and no audible bruit in kidney allograft area. Diagnosis: Transplant Doppler ultrasound showed reversal of flow in the right external iliac artery suggestive of ipsilateral proximal iliac occlusion. Pre-procedure CT demonstrated severe atherosclerotic burden within the aorta and bilateral iliac systems. The anastomosed right renal artery appeared patent. Interventions: Conventional angiogram showed occlusion of the right common and proximal external iliac arteries with retrograde perfusion of the transplant kidney via the contralateral left iliac system and aorta. Subintimal recanalization of the right iliac system was performed with angioplasty and kissing stent placement at the aortic bifurcation with stents extending into the proximal right external iliac artery. Post deployment angiogram demonstrated renewed patency of the right iliac system, with restoration of antegrade perfusion to the transplant kidney. Outcomes: The patient's blood pressure decreased significantly after the procedure, with improvement in graft function. After 6 months, the patient continued to have optimally controlled blood pressure (on 3 medications) and stable graft function (serum Cr 74 µmol/L). Teaching points: Our case describes proximal TRAS and the contribution of renal hypoperfusion to hypertension and impaired graft function, with the potential for reversibility.

Justification: La sténose de l'artère du rein transplanté (SART) est une cause bien connue et potentiellement réversible d'hypertension résistante qui touche de 1 à 23% des receveurs après l'intervention. La sténose du segment iliaque proximal de l'artère du rein transplanté (SARTprox), laquelle cause un dysfonctionnement du greffon, est moins fréquente (incidence rapportée: 2 à 3%). Elle se produit généralement entre 3 mois et 2 ans après la transplantation, mais peut se produire à tout moment. Les examens non invasifs tels que l'échographie Doppler, l'angiographie par tomodensitométrie (TDM) et l'angiographie par résonance magnétique sont utiles pour l'évaluation initiale, mais le diagnostic définitif d'une sténose hémodynamiquement significative nécessite souvent une angiographie formelle. Les SART doivent être suspectées chez tout receveur d'une greffe rénale présentant une aggravation de l'hypertension et/ou une détérioration de la fonction rénale, autrement inexpliquées. Nous présentons le cas d'une receveuse souffrant d'hypertension résistante et d'une altération de la fonction du greffon résultant d'une grave altération du flux sanguin dans le greffon causée par l'occlusion du système iliaque proximal. Présentation du cas: Une femme de 74 ans, greffée 15 ans auparavant avec un rein de donneur vivant, présentait un dysfonctionnement du greffon (Cr sérique: 229 µmol/L) et une hypertension résistante nécessitant huit médicaments antihypertenseurs. À l'examen physique, la pression artérielle était de 160/92 mm Hg et la patiente ne présentait aucune sensibilité au-dessus du greffon rénal dans le quadrant inférieur droit de l'abdomen, ni bruit audible au niveau de l'artère rénale. Diagnostic: L'échographie Doppler du greffon a montré une inversion du flux dans l'artère iliaque externe droite, ce qui suggérait une occlusion iliaque proximale ipsilatérale. La TDM avant l'intervention avait montré une charge athérosclérotique sévère dans l'aorte et les systèmes iliaques bilatéraux. L'artère rénale droite anastomosée semblait non obstruée. Intervention: L'angiographie conventionnelle a montré une occlusion de l'artère iliaque commune droite et de l'artère iliaque externe proximale, avec une perfusion rétrograde du rein transplanté via le système iliaque gauche controlatéral et l'aorte. La recanalisation sous-intimale du système iliaque droit a été réalisée par angioplastie et on a procédé à la pose d'une endoprothèse au niveau de la bifurcation aortique avec des extenseurs s'étendant dans l'artère iliaque externe droite proximale. L'angiographie post-déploiement a démontré une perméabilité renouvelée du système iliaque droit, avec restauration de la perfusion antérograde vers le rein transplanté. Résultats: Après la procédure, la pression artérielle de la patiente s'est abaissée significativement et la fonction du greffon s'est améliorée. Après 6 mois, la pression artérielle demeurait bien contrôlée (avec trois médicaments) et la fonction du greffon était stable (Cr sérique: 74 µmol/L). Enseignements tirés: Notre cas décrit une SARTprox et la contribution de l'hypoperfusion rénale à l'hypertension et à l'altération de la fonction du greffon, avec un potentiel de réversibilité.

SUPERA Stenting in the Common Femoral Artery: Early Experience and Practical Considerations.

PURPOSE: Endovascular therapy in the management of de novo common femoral disease remains controversial. Considerable interest has been generated in recent years due to recent technological advancement in the design of vascular stents. In particular, SUPERA (Abbot Vascular Inc, Santa Clara USA) stents are designed to offer increased flexibility and less adverse interactions with the arterial wall, thus making it potentially better suited for common femoral lesions. However, despite such theoretical advantages, there is lack of data in its use in clinical practice. This study provides illustrative examples of SUPERA stents in different clinical settings and contributes to important clinical data for the overall efficacy and safety profile of endovascular interventions in common femoral artery (CFA) disease. MATERIALS AND METHODS: Retrospective analysis of all endovascular CFA procedures between January 1, 2011, and December 31, 2019, was conducted. Data collected included demographics, clinical symptoms, medical comorbidities, procedural characteristics, and immediate and short-term complications. Detailed analysis was performed on the stenting cohort. RESULTS: During our study period, a total of 69 patients underwent endovascular interventions involving the CFA at our institution, of which 16 patients had stenting procedures for a total of 18 stent deployments. Technical success was achieved in all stenting procedures. A total of 15 SUPERA stents were placed in 13 patients. No stent fractures were observed. Overall primary patency rate of SUPERA stents at the time of 12-month follow-up was 100% in patients who had a follow-up assessment (n = 12 stents). CONCLUSION: Endovascular intervention of the CFA is an evolving topic in the interventional radiology and vascular surgery community. Recent development of newer generation of devices such as SUPERA peripheral stents offers significant potential benefits given their inherent design. Despite the theoretically promising design of the SUPERA, there is a lack of data to support its use. This study contributes important patient-level data for SUPERA stent deployments.

Imaging features of pure and mixed forms of mucinous breast carcinoma with histopathological correlation.

METHODS:: A cross-sectional study identified cases of mucinous breast carcinoma from pathology records (2004-2012). Two radiologists classified imaging features by consensus and two pathologists classified cases into pure or mixed subtypes. Bi-variable analyses were performed using relevant statistical tests. RESULTS:: We identified 80 lesions in 77 female patients (median age 65 years, range 29-88): 58 lesions on mammograhy, 72 on ultrasound, and 25 on MRI. Statistically significant findings (p < 0.05) are as follows. On mammography, tumour margins tended to be indistinct (12, 48%) and spiculated (11, 44%) for pure and mixed lesions, respectively. Pure mucinous masses were less microcalcified (23, 77%) and mixed masses equally so. On ultrasound, pure tumours tended towards an irregular or oval shape (44, 42%) with mixed tumours having an irregular shape (78%). More pure tumours (53%) had posterior acoustic enhancement than mixed lesions (33%), and all pure tumours lacked posterior acoustic shadowing. Pure lesions had a heterogeneous echo pattern more than mixed tumours (78% vs 39%). On MRI, pure tumours tended towards a persistent kinetic curve (42%) whereas mixed tumours predominantly had a washout pattern (75%). Most pure tumours were T2 hyperintense (83%) whereas mixed lesions were T2 isointense or hyperintense (61%, 23%), respectively. CONCLUSION:: An analysis of imaging features can help to infer underlying histology of pure and mixed forms of mucinous breast carcinoma. ADVANCES IN KNOWLEDGE:: Pure mucinous carcinomas present less suspicious imaging features than mixed mucinous carcinomas and could be mistaken for non malignant lesions. An imaging analysis of mucinous breast carcinoma can help infer their underlying histology.

Liver segmentation: indications, techniques and future directions.

OBJECTIVES: Liver volumetry has emerged as an important tool in clinical practice. Liver volume is assessed primarily via organ segmentation of computed tomography (CT) and magnetic resonance imaging (MRI) images. The goal of this paper is to provide an accessible overview of liver segmentation targeted at radiologists and other healthcare professionals. METHODS: Using images from CT and MRI, this paper reviews the indications for liver segmentation, technical approaches used in segmentation software and the developing roles of liver segmentation in clinical practice. RESULTS: Liver segmentation for volumetric assessment is indicated prior to major hepatectomy, portal vein embolisation, associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) and transplant. Segmentation software can be categorised according to amount of user input involved: manual, semi-automated and fully automated. Manual segmentation is considered the "gold standard" in clinical practice and research, but is tedious and time-consuming. Increasingly automated segmentation approaches are more robust, but may suffer from certain segmentation pitfalls. Emerging applications of segmentation include surgical planning and integration with MRI-based biomarkers. CONCLUSIONS: Liver segmentation has multiple clinical applications and is expanding in scope. Clinicians can employ semi-automated or fully automated segmentation options to more efficiently integrate volumetry into clinical practice. TEACHING POINTS: • Liver volume is assessed via organ segmentation on CT and MRI examinations. • Liver segmentation is used for volume assessment prior to major hepatic procedures. • Segmentation approaches may be categorised according to the amount of user input involved. • Emerging applications include surgical planning and integration with MRI-based biomarkers.

Acute calcific tendinopathy of the popliteus tendon: a rare case diagnosed using a multimodality imaging approach and treated conservatively.

Acute calcific tendinopathy of the popliteus tendon is a rare medical entity associated with significant patient discomfort. We present the case of a previously healthy 48-year-old female who presented to the emergency department with acute onset of left knee pain. Initial radiographs revealed calcifications within the posterolateral compartment of the knee. Ultrasound imaging demonstrated a swollen and hypoechoic popliteus tendon with an increased color Doppler signal at the periphery of the tendon as well as calcification in the tendon and adjacent soft tissues. Subsequently performed MRI revealed a thickened and heterogeneous popliteus tendon near its femoral attachment with marked edematous changes surrounding the tendon. Local ultrasound-guided glucocorticoid injection had successful clinical results with no recurrence at 8-month follow-up. In this case report we review the literature for similar previously reported cases. This case report of popliteus tendon calcific tendinopathy provides comprehensive multimodality imaging findings and a description of its non-surgical management.

Liver Segmentation on CT and MR Using Laplacian Mesh Optimization.

OBJECTIVE: The purpose of this paper is to describe a semiautomated segmentation method for the liver and evaluate its performance on CT-scan and MR images. METHODS: First, an approximate 3-D model of the liver is initialized from a few user-generated contours to globally outline the liver shape. The model is then automatically deformed by a Laplacian mesh optimization scheme until it precisely delineates the patient's liver. A correction tool was implemented to allow the user to improve the segmentation until satisfaction. RESULTS: The proposed method was tested against 30 CT-scans from the SLIVER07 challenge repository and 20 MR studies from the Montreal University Hospital Center, covering a wide spectrum of liver morphologies and pathologies. The average volumetric overlap error was 5.1% for CT and 7.6% for MRI and the average segmentation time was 6 min. CONCLUSION: The obtained results show that the proposed method is efficient, reliable, and could effectively be used routinely in the clinical setting. SIGNIFICANCE: The proposed approach can alleviate the cumbersome and tedious process of slice-wise segmentation required for precise hepatic volumetry, virtual surgery, and treatment planning.

Comparison of MRI- and CT-based semiautomated liver segmentation: a validation study.

PURPOSE: To compare the repeatability, agreement, and efficiency of MRI- and CT-based semiautomated liver segmentation for the assessment of total and subsegmental liver volume. METHODS: This retrospective study was conducted in 31 subjects who underwent contemporaneous liver MRI and CT. Total and subsegmental liver volumes were segmented from contrast-enhanced 3D gradient-recalled echo MRI sequences and CT images. Semiautomated segmentation was based on variational interpolation and Laplacian mesh optimization. All segmentations were repeated after 2 weeks. Manual segmentation of CT images using an active contour tool was used as the reference standard. Repeatability and agreement of the methods were evaluated with intra-class correlation coefficients (ICC) and Bland-Altman analysis. Total interaction time was recorded. RESULTS: Intra-reader ICC were ≥0.987 for MRI and ≥0.995 for CT. Intra-reader repeatability was 30 ± 217 ml (bias ± 1.96 SD) (95% limits of agreement: -187 to 247 ml) for MRI and -10 ± 143 ml (-153 to 133 ml) for CT. Inter-method ICC between semiautomated and manual volumetry were ≥0.995 for MRI and ≥0.986 for CT. Inter-method segmental ICC varied between 0.584 and 0.865 for MRI and between 0.596 and 0.890 for CT. Inter-method agreement was -14 ± 136 ml (-150 to 122 ml) for MRI and 50 ± 226 ml (-176 to 276 ml) for CT. Inter-method segmental agreement ranged from 10 ± 47 ml (-37 to 57 ml) to 2 ± 214 ml (-212 to 216 ml) for MRI and 9 ± 45 ml (-36 to 54 ml) to -46 ± 183 ml (-229 to 137 ml) for CT. Interaction time (mean ± SD) was significantly shorter for MRI-based semiautomated segmentation (7.2 ± 0.1 min, p < 0.001) and for CT-based semiautomated segmentation (6.5 ± 0.2 min, p < 0.001) than for CT-based manual segmentation (14.5 ± 0.4 min). CONCLUSION: MRI-based semiautomated segmentation provides similar repeatability and agreement to CT-based segmentation for total liver volume.

Clinical significance of parotid gland incidentalomas on (18)F-FDG PET/CT.

The aim of this study was to evaluate the frequency and clinical significance of incidental focal uptake of (18)F-fluorodeoxyglucose (FDG) on positron emission tomography/computed tomography (PET/CT) in the parotid glands of cancer patients. A retrospective review of 7,252 oncologic PET/CT studies was done. FDG positive parotid incidentalomas occurred in 0.4% of PET/CT scans, of which only 4% were malignant. PET/CT was unable to differentiate benign from malignant parotid lesions based on SUVmax alone. (18)F-FDG positive parotid incidentalomas can be managed conservatively, however patients with a prior history of lymphoma had a much higher risk of parotid malignancy and require further investigation.

Validation of a semiautomated liver segmentation method using CT for accurate volumetry.

RATIONALE AND OBJECTIVES: To compare the repeatability and agreement of a semiautomated liver segmentation method with manual segmentation for assessment of total liver volume on CT (computed tomography). MATERIALS AND METHODS: This retrospective, institutional review board-approved study was conducted in 41 subjects who underwent liver CT for preoperative planning. The major pathologies encountered were colorectal cancer metastases, benign liver lesions and hepatocellular carcinoma. This semiautomated segmentation method is based on variational interpolation and 3D minimal path-surface segmentation. Total and subsegmental liver volumes were segmented from contrast-enhanced CT images in venous phase. Two image analysts independently performed semiautomated segmentations and two other image analysts performed manual segmentations. Repeatability and agreement of both methods were evaluated with intraclass correlation coefficients (ICC) and Bland-Altman analysis. Interaction time was recorded for both methods. RESULTS: Bland-Altman analysis revealed an intrareader agreement of -1 ± 27 mL (mean ± 1.96 standard deviation) with ICC of 0.999 (P < .001) for manual segmentation and 12 ± 97 mL with ICC of 0.991 (P < .001) for semiautomated segmentation. Bland-Altman analysis revealed an interreader agreement of -4 ± 22 mL with ICC of 0.999 (P < .001) for manual segmentation and 5 ± 98 mL with ICC of 0.991 (P < .001) for semiautomated segmentation. Intermethod agreement was found to be 3 ± 120 mL with ICC of 0.988 (P < .001). Mean interaction time was 34.3 ± 16.7 minutes for the manual method and 8.0 ± 1.2 minutes for the semiautomated method (P < .001). CONCLUSIONS: A semiautomated segmentation method can substantially shorten interaction time while preserving a high repeatability and agreement with manual segmentation.