Value of deep-learning image reconstruction at submillisievert CT for evaluation of the female pelvis

AIM

To assess the value of deep-learning reconstruction (DLR) at submillisievert computed tomography (CT) for the evaluation of the female pelvis, with standard dose (SD) hybrid iterative reconstruction (IR) images as reference.

MATERIALS AND METHODS

The present study enrolled 50 female patients consecutively who underwent contrast-enhanced abdominopelvic CT for clinically indicated reasons. Submillisievert pelvic images were acquired using a noise index of 15 for low-dose (LD) scans, which were reconstructed with DLR (body and body sharp), hybrid-IR, and model-based IR (MBIR). Additionally, SD scans were reconstructed with a noise index of 7.5 using hybrid-IR. Radiation dose, quantitative image quality, overall image quality, image appearance using a five-point Likert scale (1-5: worst to best), and lesion evaluation in both SD and LD images were analysed and compared.

RESULTS

The submillisievert pelvic CT examinations showed a 61.09 ± 4.13% reduction in the CT dose index volume compared to SD examinations. Among the LD images, DLR (body sharp) had the highest quantitative quality, followed by DLR (body), MBIR, and hybrid-IR. LD DLR (body) had overall image quality comparable to the reference (p=0.084) and favourable image appearance (p=0.209). In total, 40 pelvic lesions were detected in both SD and LD images. LD DLR (body and body sharp) exhibited similar diagnostic confidence (p=0.317 and 0.096) compared with SD hybrid-IR.

CONCLUSION

DLR algorithms, providing comparable image quality and diagnostic confidence, are feasible in submillisievert abdominopelvic CT. The DLR (body) algorithm with favourable image appearance is recommended in clinical settings.

[Predictive value of MRI pelvic measurements for "difficult pelvis" during total mesorectal excision]

Objective: Total mesorectal resection (TME) is difficult to perform for rectal cancer patients with anatomical confines of the pelvis or thick mesorectal fat. This study aimed to evaluate the ability of pelvic dimensions to predict the difficulty of TME, and establish a nomogram for predicting its difficulty. Methods: The inclusion criteria for this retrospective study were as follows: (1) tumor within 15 cm of the anal verge; (2) rectal cancer confirmed by preoperative pathological examination; (3) adequate preoperative MRI data; (4) depth of tumor invasion T1-4a; and (5) grade of surgical difficulty available. Patients who had undergone non-TME surgery were excluded. A total of 88 patients with rectal cancer who underwent TME between March 2019 and November 2021 were eligible for this study. The system for scaling difficulty was as follows: Grade I, easy procedure, no difficulties; Grade II, difficult procedure, but no impact on specimen quality (complete TME); Grade III, difficult procedure, with a slight impact on specimen quality (near-complete TME); Grade IV: very difficult procedure, with remarkable impact on specimen quality (incomplete TME). We classified Grades I-II as no surgical difficulty and grades III-IV as surgical difficulty. Pelvic parameters included pelvic inlet length, anteroposterior length of the mid-pelvis, pelvic outlet length, pubic tubercle height, sacral length, sacral depth, distance from the pubis to the pelvic floor, anterior pelvic depth, interspinous distance, and inter-tuberosity distance. Univariate and multivariate logistic regression analyses were performed to identify the factors associated with the difficulty of TME, and a nomogram predicting the difficulty of the procedure was established. Results: The study cohort comprised 88 patients, 30 (34.1%) of whom were classified as having undergone difficult procedures and 58 (65.9%) non-difficult procedures. The median age was 64 years (56-70), 51 patients were male and 64 received neoadjuvant therapy. The median pelvic inlet length, anteroposterior length of the mid-pelvis, pelvic outlet length, pubic tubercle height, sacral length, sacral depth, distance from the pubis to the pelvic floor, anterior pelvic depth, interspinous distance, and inter-tuberosity distance were 12.0 cm, 11.0 cm, 8.6 cm, 4.9 cm, 12.6 cm, 3.7 cm, 3.0 cm, 13.3 cm, 10.2 cm, and 12.2 cm, respectively. Multivariable analyses showed that preoperative chemoradiotherapy (OR=4.97,95% CI: 1.25-19.71, P=0.023), distance between the tumor and the anal verge (OR=1.31, 95% CI: 1.02-1.67, P=0.035) and pubic tubercle height (OR=3.36, 95% CI: 1.56-7.25, P=0.002) were associated with surgical difficulty. We then built and validated a predictive nomogram based on the above three variables (AUC = 0.795, 95%CI: 0.696-0.895). Conclusion: Our research demonstrated that our system for scaling surgical difficulty of TME is useful and practical. Preoperative chemoradiotherapy, distance between tumor and anal verge, and pubic tubercle height are risk factors for surgical difficulty. These data may aid surgeons in planning appropriate surgical procedures.

[The Chinese guidelines for the diagnosis and treatment of pancreatic neuroendocrine neoplasms (2020)]

Pancreatic neuroendocrine neoplasms (pNENs) are highly heterogeneous, and the management of pNENs patients can be intractable. To address this challenge, an expert committee was established on behalf of the Group of Pancreatic Surgery, Chinese Society of Surgery, Chinese Medical Association, which consisted of surgical oncologists, gastroenterologists, medical oncologists, endocrinologists, radiologists, pathologists, and nuclear medicine specialists. By reviewing the important issues regarding the diagnosis and treatment of pNENs, the committee concluded evidence-based statements and recommendations in this article, in order to further improve the management of pNENs patients in China.

Simultaneous multi-slice accelerated diffusion-weighted imaging with higher spatial resolution for patients with liver metastases from neuroendocrine tumours

AIM

To evaluate the imaging characteristics of simultaneous multi-slice (SMS) accelerated diffusion-weighted imaging (DWI) with decreased section thickness, with and without motion correction, in comparison to conventional DWI (cDWI) for the detection of lesions in patients with neuroendocrine tumour (NET) liver metastases.

MATERIALS AND METHODS

Fifteen patients with NET liver metastases underwent cDWI (section thickness [SL]=4 mm) and SMS-DWI (SL=2 mm). Non-linear motion-corrected (Moco)-SMS-DWI was generated in addition to the original series. Qualitative imaging characteristics (five-point Likert scale), the number of high signal lesions, and the detectability and delineation of lesions were evaluated and compared using the Friedman and the Dunn-Bonferroni tests. The test-retest variability (TRV) of the cDWI and SMS-DWI techniques was investigated among 11 healthy volunteers who underwent cDWI (SL=4 mm) and SMS-DWI (SL=4 mm) twice. The Friedman and the Dunn-Bonferroni post-hoc tests were used to compare the mean apparent diffusion coefficient (ADC) and the TRV in different liver regions between the three series.

RESULTS

Moco-SMS-DWI demonstrated significantly superior overall image quality (p<0.001) with significantly fewer artefacts (p=0.003) than cDWI. The number of lesions detected by cDWI, SMS-DWI, and Moco-SMS-DWI were 348, 504, and 523, respectively. The detectability and delineation of the lesions and the ADC values were significantly higher on the SMS-DWI and Moco-SMS-DWI images than on the cDWI images (all p<0.001). Moco-SMS-DWI showed significantly higher TRV than cDWI in regions near the liver edge (p=0.018).

CONCLUSIONS

SMS-DWI achieves higher spatial resolution than cDWI within the same acquisition time, detects more lesions, and provides better lesion delineation. By applying motion correction, the TRV of DWI could be enhanced in regions near the liver edge.

[The 465th case: intestinal obstruction, gastrointestinal hemorrhage and duodenal fistula]

This is a complicated and difficult case. The onset symptom of a 62-year-old male was recurrent intestinal obstruction. Ileocecal and ileocolic operation was done twice. Massive gastrointestinal bleeding occurred due to giant fistula of descending duodenum, which connected to ileocolic anastomosis. After consultation by multidisciplinary team, jejunal-feeding tube was placed to provide enteral nutrition. With general condition improving, duodenal fistula repair and involved bowel resection were performed. Postoperative pathology confirmed Crohn's disease. The patient was treated with thalidomide and recovered well during follow-up.

Uric acid versus non-uric acid urinary stones: differentiation with single energy CT texture analysis

AIM

To evaluate the accuracy of computed tomography (CT) texture analysis (TA) to differentiate uric acid (UA) stones from non-UA stones on unenhanced CT in patients with urinary calculi with ex vivo Fourier transform infrared spectroscopy (FTIR) as the reference standard.

MATERIALS AND METHODS

Fourteen patients with 18 UA stones and 31 patients with 32 non-UA stones were included. All the patients had preoperative CT evaluation and subsequent surgical removal of the stones. CTTA was performed on CT images using commercially available research software. Each texture feature was evaluated using the non-parametric Mann-Whitney test. Receiver operating characteristic (ROC) curves were created and the area under the ROC curve (AUC) was calculated for texture parameters that were significantly different. The features were used to train support vector machine (SVM) classifiers. Diagnostic accuracy was evaluated.

RESULTS

Compared to non-UA stones, UA stones had significantly lower mean, standard deviation and mean of positive pixels but higher kurtosis (p<0.001) on both unfiltered and filtered texture scales. There were no significant differences in entropy or skewness between UA and non-UA stones. The average SVM accuracy of texture features for differentiating UA from non-UA stones ranged from 88% to 92% (after 10-fold cross validation). A model incorporating standard deviation, skewness, and kurtosis from unfiltered texture scale images resulted in an AUC of 0.965±00.029 with a sensitivity of 94.4% and specificity of 93.7%.

CONCLUSION

CTTA can be used to accurately differentiate UA stones from non-UA stones in vivo using unenhanced CT images.

[A comparison between the revision of Atlanta classification and determinant-based classification in acute pancreatitis]

Objective: To compare the performance of the revision of Atlanta classification (RAC) and determinant-based classification (DBC) in acute pancreatitis. Methods: Consecutive patients with acute pancreatitis admitted to a single center from January 2001 to January 2015 were retrospectively analyzed. Patients were classified into mild, moderately severe and severe categories based on RAC and were simultaneously classified into mild, moderate, severe and critical grades according to DBC. Disease severity and clinical outcomes were compared between subgroups. The receiver operating curve (ROC) was used to compare the utility of RAC and DBC by calculating the area under curve (AUC). Results: Among 1 120 patients enrolled, organ failure occurred in 343 patients (30.6%) and infected necrosis in 74 patients(6.6%). A total of 63 patients (5.6%) died. Statistically significant difference of disease severity and outcomes was observed between all the subgroups in RAC and DBC (P<0.001). The category of critical acute pancreatitis (with both persistent organ failure and infected necrosis) had the most severe clinical course and the highest mortality (19/31, 61.3%). DBC had a larger AUC (0.73, 95%CI 0.69-0.78) than RAC (0.68, 95%CI 0.65-0.73) in classifying ICU admissions (P=0.031), but both were similar in predicting mortality(P=0.372) and prolonged ICU stay (P=0.266). Conclusions: DBC and RAC perform comparably well in categorizing patients with acute pancreatitis regarding disease severity and clinical outcome. DBC is slightly better than RAC in predicting prolonged hospital stay. Persistent organ failure and infected necrosis are risk factors for poor prognosis and presence of both is associated with the most dismal outcome.

[Clinical and radiologic characteristics of craniomaxillofacial primary tumor induced osteomalacia: a retrospective analysis]

OBJECTIVE

To investigate the diagnosis strategy, radiology and clinical pathology feature of craniomaxillofacial primary tumor induced osteomalacia.

METHODS

Twelve cases of craniomaxillofacial primary tumor induced osteomalacia were reviewed, including 5 male and 7 female with a age range from 16 to 69 years. The clinical characteristics, radiology examinations and pathological features were analyzed.

RESULTS

The craniomaxillofacial primary tumor induced osteomalacia occurred in different ages, with 2 to 30 years of medical history. Seven of the twelve cases were octreotide scintigraphy positive, nine of the twelve cases invaded bone, exhibiting destruction of the adjacent cortex, ten of the twelve showed gingival lesions of local thickening or epulis. The tumor arises from mesenchymal tissue, infiltrating local gingiva and bone trabecular with spindle like fibroblasts and dental epithelial rests.

CONCLUSIONS

The concealed nature of the tumor induced osteomalacia requires multiple methods to locate the primary tumor and the tumors located in craniomaxillofacial region have unique clinical and pathological features.

Dual-source dual-energy computed tomography angiography for active gastrointestinal bleeding: a preliminary study

AIM

To assess the utility of dual-source dual-energy computed tomography angiography (DSDECTA) in the diagnosis of active gastrointestinal bleeding (GIB).

MATERIALS AND METHODS

From June 2010 to September 2011, 58 consecutive patients with clinical signs of active GIB underwent DSDECTA. Two radiologists, blinded to clinical data, interpreted images from DSDECTA independently, with discordant interpretation resolved by consensus. The standards of reference included digital subtraction angiography, endoscopy, surgery, or final pathology reports. Sensitivity, specificity, positive (PPV) and negative (NPV) predictive values, and accuracy of DSDECTA for detection of active GIB were evaluated. Receiver-operating characteristic (ROC) analysis was undertaken and the area under the curve (AUC) calculated.

RESULTS

Active GIB source was identified in 39 of 58 patients (67.2%), all of which were confirmed by one or more reference standard. Negative DSDECTA results were obtained in 19 patients (32.8%). Of these, 15 patients did not require any further intervention and were discharged without incident. The overall sensitivity, specificity, PPV, NPV, and accuracy of DSDECTA was 88.6, 100, 100, 73.7, and 91.4%, respectively. The AUC was 0.935 ± 0.063. The dose reduction of a dual-phase DSDECTA protocol was approximately 30%, compared with that of a triple-phase protocol used in a previous study.

CONCLUSION

DSDECTA can act as an accurate method for detection and localization of active GIB and has a relatively low radiation dose.