Plain computed tomography for differentiating neoplastic and non-neoplastic pedunculated gallbladder polyps

AIMS

Surgery is recommended for large pedunculated gallbladder polyps (PGPs), which measure 10 mm or more in size, because they tend to be neoplastic polyps (NPs), such as adenomas and adenocarcinomas. However, after resection, they are often found to be non-neoplastic polyps (non-NPs). This study aimed to evaluate the usefulness of plain CT in distinguishing NPs from non-NPs.

METHODS

Of the 80 patients who underwent cholecystectomy for PGPs ( 10 mm between January 2008 and February 2021, 46 who underwent plain and contrast-enhanced CT (CE-CT) before resection were included in this study. We retrospectively assessed the polyp detection rate (PDR) using CT and calculated the difference in the CT values between PGPs and the surrounding bile.

RESULTS

Twenty-one patients had NPs (12 adenomas, 5 carcinomas in adenoma, and 4 adenocarcinomas). The others were non-NPs (24 cholesterol polyps and one hyperplastic polyp). The PDR using plain CT was significantly higher in the NP group than in the non-NP group (38% (8/21) vs. 0% (0/25), p <0.01). The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of NPs were 38%, 100%, 100%, 66%, and 72%, respectively. The difference in the CT values between PGPs and the surrounding bile was significantly larger in the NP group than in the non-NP group (14.12 ± 11.38 HU, 5.04 ± 6.15 HU, p <0.01).

CONCLUSIONS

PGPs detected using plain CT had a high probability of being NPs. Plain CT is therefore considered to be useful for differentiating NPs from non-NPs.

Combining polyp diameter and polyp-to-bile ratio by dynamic contrast-enhanced CT scanning can improve the diagnostic specificity of gallbladder neoplastic polyps

OBJECTIVE

This study aimed to distinguish between cholesterol and neoplastic gallbladder polyps using dynamic contrast-enhanced CT.

METHODS

The dataset retrospectively comprised 222 cases, including 106 cases of cholesterol polyps and 116 cases of neoplastic polyps (59 adenoma and 57 adenocarcinoma). The perception and Hounsfield units of the polyps and gallbladder bile were assessed by contrast-enhanced CT, and the polyp-to-bile ratio (PBR) was calculated. Receiver operating characteristic (ROC) curves and area under the curve analyses were used to assess the diagnostic value of the diameter and PBR for neoplastic polyps.

RESULTS

The diameter of cholesterol polyps was significantly smaller than that of neoplastic polyps. The proportion of perceived cholesterol polyps in the plain and arterial phases of CT were significantly lower than those of neoplastic polyps (p < .001). On the contrary, the CT values of gallbladder bile of cholesterol polyps were always significantly higher than those of neoplastic polyps (p < .001). The median PBR values of cholesterol polyps were significantly lower than those of neoplastic polyps (p ≤ .001). ROC analysis showed that diameter and a plain phase PRB had better diagnostic value for neoplastic polyps. Polyp diameter ≥ 11.95 mm and the plain phase PBR ≥1.48 were the optimal cut-off values for diagnosis of neoplastic polyps. Combining a diameter ≥ 12 mm and a PBR in the plain phase ≥1.48 further improved neoplastic polyp diagnostic specificity and positive likelihood ratio (10.453).

CONCLUSIONS

Polyp-to-bile ratio in contrast-enhanced CT scanning is a new and convenient index for identifying cholesterol and neoplastic gallbladder polyps.

Longitudinal Ultrasound Assessment of Changes in Size and Number of Incidentally Detected Gallbladder Polyps

BACKGROUND. Previous European multisociety guidelines recommend routine follow-up imaging of gallbladder polyps (including polyps < 6 mm in patients without risk factors) and cholecystectomy for polyp size changes of 2 mm or more. OBJECTIVE. The purpose of this study was to assess longitudinal changes in the number and size of gallbladder polyps on serial ultrasound examinations. METHODS. This retrospective study included patients who underwent at least one ultrasound examination between January 1, 2010, and December 31, 2020 (as part of a hepatocellular carcinoma screening and surveillance program) that showed a gallbladder polyp. Number of polyps and size of largest polyp were recorded based primarily on review of examination reports. Longitudinal changes on serial examinations were summarized. Pathologic findings from cholecystectomy were reviewed. RESULTS. Among 9683 patients, 759 (8%) had at least one ultrasound examination showing a polyp. Of these, 434 patients (248 men, 186 women; mean age, 50.6 years) had multiple examinations (range, 2-19 examinations; mean, 4.8 examinations per patient; mean interval between first and last examinations, 3.6 ± 3.1 [SD] years; maximum interval, 11.0 years). Among these 434 patients, 257 had one polyp, 40 had two polyps, and 137 had more than two polyps. Polyp size was 6 mm or less in 368 patients, 7-9 mm in 52 patients, and 10 mm or more in 14 patients. Number of polyps increased in 9% of patients, decreased in 14%, both increased and decreased on serial examinations in 22%, and showed no change in 55%. Polyp size increased in 10% of patients, decreased in 16%, both increased and decreased on serial examinations in 18%, and showed no change in 56%. In 9% of patients, gallbladder polyps were not detected on follow-up imaging; in 6% of patients, gallbladder polyps were not detected on a follow-up examination but were then detected on later studies. No gallbladder carcinoma was identified in 19 patients who underwent cholecystectomy. CONCLUSION. Gallbladder polyps fluctuate in size, number, and visibility over serial examinations. Using a 2-mm threshold for growth, 10% increased in size. No carcinoma was identified. CLINICAL IMPACT. European multisociety guidelines that propose surveillance of essentially all polyps and a 2-mm size change as the basis for cholecystectomy are likely too conservative for clinical application.

Conventional Ultrasound Combined With Contrast-Enhanced Ultrasound in Differential Diagnosis of Gallbladder Cholesterol and Adenomatous Polyps (1-2 cm)

OBJECTIVES

This study aimed to determine ultrasonic image characteristics that enable differentiation between cholesterol and adenomatous polyps and to assess the diagnostic efficacy of combining conventional ultrasound (CUS) with contrast-enhanced ultrasound (CEUS).

METHODS

Eighty-nine patients with gallbladder polyps of 1-2 cm in diameter were enrolled and examined by CUS and CEUS before cholecystectomy. The appearances on CUS and CEUS were recorded and analyzed. The receiver operating characteristic (ROC) curve was used to calculate the optimal size threshold for distinguishing cholesterol from adenomatous polyps. A logistic regression analysis was performed to identify diagnostic variables. ROC analysis was performed to evaluate the diagnostic efficacy of the size, the independent variables, and the combined factors.

RESULTS

There were differences in size, number, vascularity on CUS and intralesional vascular shape, wash-out, and area under the curve on CEUS between the two groups (P < .05). ROC analysis indicated that a maximum diameter of 1.45 cm was the optimal threshold for the prediction of adenomatous polyps. The logistic regression analysis proved that the single polyp, presence of vascularity, and intralesional linear vessels were associated with adenomatous polyps (P < .05). ROC analysis showed that the area under the ROC curve, sensitivity, and specificity for the combination of the three independent variables were 0.858, 87.3%, and 67.6%. The number combined with intralesional vascular shape had the highest diagnostic sensitivity of 91.2%.

CONCLUSIONS

The combination of CUS and CEUS demonstrated great significance in the differential diagnosis of cholesterol and adenomatous polyps.

Is there a role for growth status in distinguishing gallbladder adenomas from cholesterol polyps? - A retrospective study based on 520 cholecystectomy patients

INTRODUCTION

Gallbladder adenomas have cancerous potential and occur in 4-8.9% of gallbladder polyps. The growth status (size progression and growth rate during follow-up) of polyps and their effectiveness for predicting adenomas are poorly defined. Herein, we compared adenomas and cholesterol polyps based on the growth status and evaluated the reported risk factors in predicting neoplasm.

METHODS

We enrolled 520 patients who underwent preoperative ultrasonic follow-up more than 6 months with post-cholecystectomy pathologically confirmed gallbladder polyps. The patients were classified into adenoma and cholesterol polyp groups. Growth status, clinical characteristics, laboratory data, ultrasonic findings were reviewed and compared between the groups.

RESULTS

Seventy-nine adenomas and 441 cholesterol polyps were analyzed. The mean diameter of adenomas (cholesterol polyps) was 7.24 ± 4.36 mm (6.23 ± 2.88 mm) in the initial and 12.06 ± 4.61 mm (10.05 ± 2.95 mm) in the preoperative examination. The median size progression (range) of polyps in the cholesterol polyps [3 (0, 22)] mm was smaller than that in adenomas [4 (0, 21)] mm (p = .075). The mean growth rate of adenomas (1.07 ± 1.33 mm/6 months) was slightly faster than in cholesterol polyps (0.83 ± 1.04 mm/6 months) (p = .338). The indicators significantly associated with adenomas were age >49.5 years, lack of gallbladder polyps/cholelithiasis family history, polyp size >11.5 mm and solitary polyp (p = .005, p = .027, p = .001, and p = .021, respectively).

CONCLUSION

Growth status was not a valuable modality to distinguishing gallbladder adenomas from cholesterol polyps. Risk factors such as age, polyp size, and solitary polyp were effective in predicting adenomas.

Detectability on Plain CT is an Effective Discriminator between Carcinoma and Benign Disorder for a Polyp >10 mm in the Gallbladder

An appropriate diagnosis is required to avoid unnecessary surgery for gallbladder cholesterol polyps (GChPs) and to appropriately treat pedunculated gallbladder carcinomas (GCs). Generally, polyps >10 mm are regarded as surgical candidates. We retrospectively evaluated plain and contrast-enhanced (CE) computed tomography (CT) findings and histopathological features of 11 early GCs and 10 GChPs sized 10–30 mm to differentiate between GC and GChP >10 mm and determine their histopathological background. Patient characteristics, including polyp size, did not significantly differ between groups. All GCs and GChPs were detected on CE-CT; GCs were detected more often than GChPs on plain CT (73% vs. 9%; p < 0.01). Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy for GCs were 73%, 90%, 89%, 75%, and 81%, respectively. On multivariate analysis, lesion detectability on plain CT was independently associated with GCs (odds ratio, 27.1; p = 0.044). Histopathologically, GChPs consisted of adipose tissue. Although larger vessel areas in GCs than in GChPs was not significant (52,737 μm² vs. 31,906 μm²; p = 0.51), cell densities were significantly greater in GCs (0.015/μm² vs. 0.0080/μm²; p < 0.01). Among GPs larger than 10 mm, plain CT could contribute to differentiating GCs from GChPs.