OBJECTIVETo explore the significance of multi-detector CT (MDCT) in differential diagnosis of papillary renal cell carcinoma and chromophobe renal cell carcinoma.

METHODSClinical data of forty-one cases of renal cancers confirmed pathologically were collected, including 21 cases of papillary renal cell carcinoma (PRCC) (14 type I, 7 type II) and 20 cases of chromophobe renal cell carcinoma (ChRCC). Their morphological and MDCT characteristics were retrospectively analyzed. Receiver operator characteristic curve (ROC) was used to analyze the value of MDCT in differential diagnosis of PRCC and ChRCC. Two senior radiologists analyzed the morphological and the dynamic enhancement characteristics of the images. The attenuation of the lesions and the adjacent renal parenchyma were measured. The morphological indexes were compared with chi-square test and the quantitative indexes were compared with independent sample T-test. Receiver operator characteristic curve (ROC) was used to analyze the sensitivity, specificity and accuracy of diagnosis of PRCC and ChRCC.

RESULTSAngioid enhancement and filled enhancement were more common in ChRCC than in PRCC, while delayed enhancement was more often seen in PRCC than in ChRCC. Calcification was more common in type I than type II PRCC. The enhancement value (ΔCT value) in corticomedullary phase was (29.08 ± 20.12) Hu for PRCC, significantly lower than the (48.29 ± 26.70) Hu for ChRCC (t = -2.611, P = 0.013). The ΔCT value of type I PRCC in corticomedullary phase was (26.36 ± 18.16) Hu, showing a significant difference from that of ChRCC (t = -2.666, P = 0.012). The lesion to kidney ratio (LKR) in corticomedullary phase was 0.44 ± 0.19 for PRCC and 0.58 ± 0.15 for ChRCC, with a significant difference between them (t = -2.587, P = 0.014). The LKR of type I PRCC in corticomedullary phase was 0.39 ± 0.15, showing a significant difference from that of ChRCC (t = -3.628, P = 0.001). The difference value (D-value) of the attenuation of lesion between corticomedullary and nephrographic phases was (-3.69 ± 8.90) Hu for PRCC and (8.39 ± 21.98) Hu for ChRCC, with a significant difference between them (t = -2.285, P = 0.031). The D-value of type I PRCC was (-4.55 ± 9.82) Hu, showing a significant difference from that of ChRCC (t = -2.323, P = 0.028). There was no significant difference between the ΔCT, LKR and D-value of the type II PRCC and ChRCC (P > 0.05 for all). The area under the curve (AUC) for ΔCT value, LKR value in corticomedullary phase, and D-value were 0.718, 0.751 and 0.668, respectively, and there were no significant differences among them (z values were 0.896, 0.683 and 0.559, respectively, and P values were 0.370, 0.495 and 0.576, respectively). Using 49.350 Hu as the cutoff value for ΔCT value in corticomedullary phase, resulted in a sensitivity, specificity and accuracy of 50.0%, 90.5% and 70.7%, respectively. Corresponding values were 65.0%, 81.0% and 73.2%, when using a cutoff value of 0.532 for LKR in corticomedullary phase, and were 60.0%, 76.2% and 68.3%, when using a D-value of 0.400 Hu.

CONCLUSIONSThe ΔCT value, LKR value in corticomedullary phase, and the D-value are all useful indexes for the differentiation of PRCC and ChRCC.

Area Under Curve ; Calcinosis ; Carcinoma, Renal Cell ; diagnosis ; Diagnosis, Differential ; Humans ; Kidney ; Kidney Neoplasms ; diagnosis ; ROC Curve ; Retrospective Studies ; Sensitivity and Specificity

Objective:To investigate soft-and hard-tissue changes after simultaneously labial and lingual augmented corticotomy in patients with insufficient alveolar bone thickness of lower anterior teeth both in labial and lingual side during orthodontic treatment.Methods:From January 2021 to June 2022, 10 patients [2 males and 8 females, (26.2±3.1) years old] who received orthodontic and orthognathic combined treatment from the Fourth Clinical Division, Peking University School and Hospital of Stomatology were selected. The alveolar bone thickness of lower anterior teeth both in labial and lingual side in these patients was less than 0.5 mm according to cone-beam CT examination before or during treatment, and 60 lower anterior teeth were included. The 10 patients were treated with simultaneously labial and lingual augmented corticotomy. The differences in gingival recession, papilla index and the differences in labial and lingual alveolar bone thickness of lower anterior teeth were compared.Results:Six months after surgery, the alveolar bone thicknesses at the 4 mm under cemento-enamel junction (CEJ), 8 mm under CEJ and at the apical level [labial side: (1.02±0.39), (2.22±0.89) and (4.87±1.35) mm; lingual side: (1.07±0.46), (2.31±1.04) and (3.91±1.29) mm] were significantly higher than that before surgery [labial side: (0.02±0.09), (0.06±0.21) and (2.71±1.33) mm]; lingual side: (0.14±0.29), (0.40±0.52) and (2.13±1.02) mm] ( P<0.001), respectively. The increases in alveolar bone thickness of central incisors [apical level on labial side: (2.53±1.20) mm, 8 mm under CEJ on lingual side: (2.27±1.24) mm, apical level on lingual side: (2.66±1.49) mm] and lateral incisors [apical level on labial side: (2.42±1.30) mm, 8 mm under CEJ on lingual side: (2.28±0.92) mm, apical level on lingual side: (1.94±1.15) mm] were significantly higher than that of canines [apical level on labial side: (1.52±1.47) mm, 8 mm under CEJ on lingual side: (1.17±1.09) mm,apical level on lingual side: (0.74±1.37) mm] ( P<0.01). There were no significant differences in the degree of gingival recession [labial side before surgery: (0.72±0.88) mm, lingual side before surgery: (0.80±1.09) mm; labial side 6 months after surgery: (0.72±0.81) mm,lingual side 6 months after surgery: (0.89±0.21) mm] and gingival papilla index [before surgery: 1.00(0.75, 2.00); 6 months after surgery: 1.00(1.00, 2.00) ] between pre-operation and 6 months after surgery ( P>0.05). No serious complications occurred. Conclusions:The method used in this article for simultaneously labial and lingual augmented corticotomy was safe and feasible. This surgery has positive clinical significance for the stability of the periodontal tissue in orthodontic treatment for patients with alveolar bone thickness less than 0.5 mm of lower anterior teeth both in labial and lingual side.

Objective:To evaluate the clinical effect of alveolar bone augmentation in teeth with severe periodontitis using orthodontic forced eruption.Methods:Twelve patients (5 males and 7 females) with severe periodontitis and malocclusion who visited the Department of Orthodontics and Department of Periodontology, Peking University School and Hospital of Stomatology from October 2018 to May 2022 were included in this retrospective study. The age was (38.8±6.6) years (24-49 years). A total of 16 maxillary incisors that could not be retained due to severe periodontitis were included. The orthodontic fixed appliance was used to extrude the teeth. Cone-beam CT (CBCT) images of the patients before and after orthodontic forced eruption were collected. The voxel-based registration was used to superpose the images before and after orthodontic forced eruption. The height, thickness, and apical alveolar bone area were measured on the sagittal plane. The alveolar bone volume before and after orthodontic forced eruption was measured using three-dimensional reconstruction technique, and the influencing factors related to the alveolar volume change were analyzed.Results:The results of this study showed that the eruption distance of the teeth was (2.37±0.82) mm, and the alveolar bone height increased by (1.11±0.79) and (0.98±0.79) mm ( t=3.73, P=0.010; t=4.85, P<0.001). The proximal and distal alveolar bone height increased by (1.10±0.78) and (0.86±1.08) mm, respectively ( t=5.59, P<0.001; t=3.18, P=0.006). The alveolar bone thickness decreased (0.30±0.31) mm ( t=-3.75, P=0.002) and alveolar bone area increased (6.84±5.86) mm 2 ( t=3.71, P<0.001). The alveolar bone volume increased (53±49) mm 3 ( t=4.38, P<0.001). The alveolar bone volume was moderately positively correlated with eruption distance, apical and mesial alveolar bone thickness ( r=0.55, P=0.028; r=0.63, P=0.008; r=0.67, P=0.005). Conclusions:Orthodontic forced eruption results in a favorable increase of the alveolar bone in the upper incisor that cannot be retained due to severe periodontitis, which provides better periodontal hard tissue conditions for subsequent dental implant.