During the 12 months of the study, 384 patients underwent a digestive CT scan. One hundred and twelve (112) tumors were found, a frequency of 29%. The distribution of patients by age group is shown in Figure 1 .

The majority of patients were male with a sex ratio of 1.3.

The mean age of patients was 54.9 years with extremes of 9 and 85 years. The most represented age groups were 51 - 60 years old and 61 to 70 years old. The indications for CT scans are presented in Table 1 .

Analysis of the CT scan indications reveals that the majority of patients were seen in the late stage of the disease. About 10% were carriers of the already known malignancies (11 cases).

The different types of CT scan performed were the abdominal CT scan (17%) and the abdomino-pelvic CT scan in 83% of cases; 90% of the examinations were carried out with injection of the contrast medium and 10% without injection of the contrast medium. However, due to the lack of equipment, no examination was carried out with marking of the digestive tract with water or water-soluble contrast medium. The distribution of tumours by site is presented in Table 2 .

The main tumors are, in descending order, tumors of the liver, kidneys, pancreas and colorectal.

CT analysis of the lesions made it possible to classify the lesions into benign-looking tumors and malignant-looking tumors. The appearance of the tumours is shown in Figure 2 .

The main malignancies were liver cancer, colorectal cancer and gastrointestinal cancer.

Figures 3 and 4 show images of liver cancer on cirrhosis and pancreatic head cancer.

Table 3 presents the comparison of tumours with age and sex.

There is no relationship between age and tumor type (p = 0.5).

There is a relatively very high risk of developing all three types of tumours (liver, kidney and pancreas) in females compared to females OR, [95% CI] = 2.6 [1.0 - 7.0], although this difference is not statistically significant.

Table 4 presents the comparison between sex and tumor appearance.

There is no relationship between age and the appearance of tumor malignancy (p = 0.3).

Regarding histopathological examinations, 20 patients out of 112 were removed (11.9% of cases) for histological confirmation ( Table 5 ).

GIST: Gastro intestinal stromal tumor.

Figure 5 shows histological image of a colon adenocarcinoma.

Image of Department of Pathological Anatomy National Biological Laboratory Clinical and public health.

This study describes the real conditions of the practice of medical imaging at the National Center for Medical Imaging in Bangui and anatomical pathology at the National Laboratory of Public Biology and Health in Bangui, which are the reference institutions in the Central African Republic. The lack of local expertise in interventional radiology for deep organ harvesting poses a problem for the histopathological confirmation of lesions observed on CT scan, anatomical pathology being the gold standard for the confirmation of the malignant or benign nature of a tumor. We can also note in anatomical pathology, difficulties in obtaining immunohistochemistry markers and poor completion of examination forms by certain clinicians, thus explaining the absence of certain data. Some protocols were not respected on the scanner due to a lack of equipment, in particular the protocol for the diagnosis of colorectal tumors where no markings were made. All these difficulties limit the generalizability of our results. However, it has the merit of showing the contribution of CT in the diagnosis of abdominal tumor lesions before they are confirmed or invalidated by histology. For reasons of severity, we are going to be much more interested in malignant tumors.

The majority of patients were male with a sex ratio of 1.3 without being able to find an explanation. The same observation was made by Diarra in Mali [2] who reported a sex ratio of 1.5 in a study on the epidemiology of digestive cancers in hospitals in Bamako. Oumarou [9] in Bangui obtained the same results with a sex ratio of 1.62 in a study carried out on the contribution of CT in the exploration of abdominal pathologies in Bangui. On the other hand, Nomeharisoa in Madagascar [10] and Traoré in Mali [11] reported a female predominance in 54.1% and 54.6% of cases, respectively, in their work on the epidemiology of cancers treated in medical oncology at the military hospital of Antananarivo and the epidemiological and anatomopathological aspects of cancers in Mali: data from the cancer registry. This female predominance could be justified by the large proportion of gynaeco-breast cancers in their studies, whereas our study was limited to digestive tumors.

The comparison between age, sex and the different tumors shows that there is no relationship between age and the type of tumors (p = 0.05) on the other hand there is a relatively very high risk of developing the three main types of tumors (liver, kidney and pancreas) in female people compared to male people OR, [IC 95%] = 2.6 [1.0 - 7.0], although this difference is not statistically significant.

Also, there is no relationship between age and the appearance of tumor malignancy (p = 0.3).

The most represented age group was 51 to 60 years old, which confirms that digestive tumors are the prerogative of the elderly.

Liver cancer

Data on digestive cancers in Africa and Europe are somewhat disparate. Our study reported topographically and in descending order 36.6% liver cancer, followed by 7.1% colorectal cancer, 5.3% gastrointestinal cancer, 4.5% pancreatic and kidney cancer, and 3.6% peritoneal cancer (peritoneal carcinomatosis). Our findings are superimposed on those of Kpossou in Benin in 2020 [12] with liver cancers in the lead (38.3%) followed by colorectal cancers (22.8%), gastric cancers (12%) and pancreatic cancers (11.4%). Diarra in Mali [2] found the same lesions but in a different order from ours: stomach cancer (59.1%), followed by liver cancer (19.1%), colorectal cancer (11.2%) and pancreatic cancer (7.1%). In Cameroon, Bang [13] observed different results in his work with colorectal cancer (48.9%) in the lead, followed by pancreatic cancer (19.1%) and gastric cancer (17.9%). Liver cancer accounted for 2.2% of cases. This difference would be linked to the fact that he carried out his study on operable patients.

Liver cancers are among the main cancers in the Central African Republic, this high proportion of liver cancer is correlated with the high prevalence of hepatitis B and C virus infection and the absence of a program to combat viral hepatitis B and C as reported by Bekondi [14] in the Central African Republic. The same observation is made by Nikiema in Burkina Faso [15] . The diagnosis of liver cancer was made in the majority (80.5%) on the basis of CT scan coupled with clinical and biological information (alpha fetoprotein protein) but also and above all on pre-existing liver lesions (cirrhosis). In the rest of the cases (19.5%), a fine-needle-guided ultrasound cyto puncture was performed in the presence of atypical lesions, whose enhancement kinetics after injection did not correspond to the description of HCC or fibrolamellar carcinoma and which were easily accessible to (superficial) cypuncture, i.e. no biopsy or cytopuncture could be performed due to lack of expertise if the lesion was deep. A typical HCC presents on CT as a lesion of more than 2 cm, hypo dense in spontaneous contrast, on a healthy or pathological liver, with intense enhancement in the arterial phase and late lavage [16] whereas fibrolamellar carcinoma presents as a tumor of the young subject, large at the time of discovery, without underlying liver disease, with vascular invasion (more than 80%), frequently located on the left lobe (65%) compared to HCC which is more common on the right lobe. The presence of a central scar is the rule (71% to 95% of cases) [17] . In the studies of Kouame Ngoran [18] , all liver cancers have been histologically proven. Interventional radiology has already begun to be practiced in some African countries south of the Sahara [19] [20] . The dominant histological type of liver cancers was hepatocellular carcinoma (5 cases), followed by cholangiocarcinoma (2 cases) and 1 case of metastasis. The same observation is made by Bagny in Lomé i.e. most of liver cancer were hepatocellular carcinoma [21] .

Colo rectal cancer:

According to previous studies carried out in Bangui, the diagnosis of colorectal cancer is delayed in the majority of cases. Very often (21.4% of cases) the diagnosis was made during an occlusive complication and the role of colonoscopy was mentioned in the diagnosis [4] .

Colorectal cancer was the 2nd lesion in order of frequency with 7.1% participation. The diagnosis is often made by colonoscopy, but it is an invasive examination that requires general anesthesia. The water-based colonic scanner has replaced the barium enema and it is a simple and easy examination to perform, especially in elderly subjects in case of suspected colonic cancer [22] [23] . In view of these findings, we can draw the conclusion that the actual frequency of these lesions was probably underestimated, given the conditions of the abdominal CT scan where no markings of the digestive tract were performed. The exploration of the digestive tract in a spontaneous state by the various cross-sectional imaging methods is often made difficult due to the absence of distension of the segment studied. The aim of digestive tract distension techniques (coloCT, enteroCT, gastroduodeno-CT) is to highlight parietal abnormalities in a reproducible way, with the greatest possible precision [24] . The absence of distension of the digestive tract has certainly caused the small parietal tumors to escape, drowned in the faeces. This is all the more true since all the colorectal lesions detected were larger than 3 cm associated with a clinical-radiological picture of occlusive complications.

For colorectal cancers, the analysis of surgical specimens was performed in 2 out of 8 patients, i.e. a histological confirmation rate of 25%. This low rate of histological confirmation has also been reported in the work of Kpossou. In our context, it would be linked to a delay in diagnosis, as Ngario has already pointed out in Bangui [4] . While for Kpossou and some authors [12] [25] , this could be explained by the fact that the population often buries surgical parts for cultural reasons and also for financial reasons. The histological type found for the two surgical specimens was adenocarcinoma. The same results were obtained in Togo by Darre in 2014 [26] .

Pancreatic cancer

For pancreatic cancer, CT is the gold standard in the exploration of pancreatic tumor pathology with a sensitivity of detection that varies between 70% for tumors less than or equal to 2 cm to 98% for tumors larger than 2 cm [27] [28] . In this study, pancreatic cancers were evoked on purely CT basis due to the lack of a technical platform and local expertise in interventional radiology, but in a very evocative clinical and biological context [29] . Kissi in his work in Ivory Coast also diagnosed pancreatic cancers on CT scan basis [30] .

These lesions presented on CT scan in the form of a hypodense lesion greater than 2cm, of the head of the pancreas in 4 cases and of the body of the pancreas in 1 case and which does not rise after injection of the contrast agent. For some authors, [31] [32] , medical imaging is crucial in the diagnosis of these tumors, the indication of directed aspiration under endoscopic ultrasound (PSEE) is to specify the nature of a solid mass in a “non-obvious” clinical and radiological context, i.e. in all cases of diagnostic doubt, in particular in the case of “small” lesions (<2 cm). While other authors insist on the need to take a sample. According to them, the puncture of a solid mass of the pancreas can be performed percutaneously, under ultrasound or computed tomography control, except for lesions of small size or difficult access, which PSEE is recommended [33] [34] . It is therefore imperative for the Central African Republic to strengthen its capacities in terms of interventional radiology.

Cancers gastro intestinaux

Of the 6 gastrointestinal cancers observed on CT scan, 5 presented as a large hypodense, heterogeneous tissue mass with areas of central necrosis with heterogeneous enhancement after injection of the compressive contrast product of the surrounding structures, located under the anterolateral wall of the abdomen, and responsible for a distension of the abdominal cavity, arguing in favor of a gastrointestinal stromal tumor (GIST). They were easily accessible to biopsy puncture performed by pathologists. The histological types found were 4 cases of adenocarcinoma, which is identical to the results of Bolenga Liboko [35] .

The only tumor that was not removed was located at the level of the small curvature of the stomach with which it was solidary, with which it shared the same vascularization. The CT scan was characteristic of a GIST (Gastro intestinal stromal tumor).

Peritoneal cancers

Peritoneal tumors (peritoneal carcinosis) presented on CT as nodular thickening or peritoneal masses, associated with fluid effusion. They were observed in patients with malignancies already known (ovarian or pancreatic) at the time of diagnosis.

Indeed, the diagnosis of peritoneal carcinomatosis is easy in diffuse and macronodular forms with ascites. Crude forms are more difficult to diagnose and require targeted research. CT scans allow for better lesion characterization with an etiological approach and an optimal extension assessment [36] , it contributes to the search for direct signs of carcinosis (ascites, epiploic nodules, thickening of the mesentery), indirect signs (digestive, biliary or ureteral compression). It is the most suitable routine examination to explore the anatomical complexity of the peritoneal cavity, especially if it is coupled with PET [37] .