PET/CT for differentiating between tuberculous peritonitis and peritoneal carcinomatosis: The parietal peritoneum

Diagnostic value of serum CA125 combined with PET/CT in ovarian cancer and tuberculous peritonitis in female patients

PURPOSE

To evaluate the diagnostic value of serum CA125 combined with 18F-FDG PET/CT in ovarian cancer (OC) and tuberculous peritonitis (TBP) in female patients and to establish a diagnostic scoring system.

METHOD

A total of 86 female patients (64 OC and 22 TBP) were included in this study. Serum CA125, PET/CT maximal intensity projection (MIP), maximal standardized uptake value, ovarian mass, ascites volume, and other indicators were analyzed and a diagnostic scoring system was established according to the weights of statistically significant indicators.

RESULTS

Univariate analysis showed that serum CA125 in OC and TBP patients were 2079.9 ± 1651.3 U/mL and 448.3 ± 349.5 U/mL (P < 0.001). In MIP images, abdominal lesions were focal distribution in 92.2% (59/64) of OC patients and diffuse distribution in 95.5% (21/22) of TBP patients (P < 0.001). Ovarian masses could be observed in 82.8% (53/64) OC patients and 31.8% (7/22) TBP patients (P <0.001). The other indicators were not statistically significant. Logistic regression analysis showed that serum CA125 and MIP were independent risk factors for diagnosis. A diagnostic scoring system could be established based on serum CA125, MIP and ovarian mass, and the diagnostic sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 98.4% (63/64), 95.5% (21/22), 97.7% (84/86), 98.4% (63/64), and 95.5% (21/22), respectively.

CONCLUSION

Serum CA125 combined with PET/CT is of great value in the diagnosis of OC and TBP. A simple and efficient diagnostic scoring system can be established using serum CA125, MIP image feature, and ovarian mass.

Clinical and Radiological Parameters to Discriminate Tuberculous Peritonitis and Peritoneal Carcinomatosis

It is challenging to differentiate between tuberculous peritonitis and peritoneal carcinomatosis due to their insidious nature and intersecting symptoms. Computed tomography (CT) is the modality of choice in evaluating diffuse peritoneal disease. We conducted an ambispective analysis of patients suspected as having tuberculous peritonitis or peritoneal tuberculosis between Jan 2020 to Dec 2021. The study aimed to identify the clinical and radiological features differentiating the two entities. We included 44 cases of tuberculous peritonitis and 45 cases of peritoneal carcinomatosis, with a median age of 31.5 (23.5-40) and 52 (46-61) years, respectively (p ≤ 0.001). Fever, past history of tuberculosis, and loss of weight were significantly associated with tuberculous peritonitis (p ≤ 0.001, p = 0.038 and p = 0.001). Pain in the abdomen and history of malignancy were significantly associated with peritoneal carcinomatosis (p = 0.038 and p ≤ 0.001). Ascites was the most common radiological finding. Loculated ascites, splenomegaly and conglomeration of lymph nodes predicted tuberculous peritonitis significantly (p ≤ 0.001, p = 0.010, p = 0.038). Focal liver lesion(s) and nodular omental involvement were significantly associated with peritoneal carcinomatosis (p = 0.011, p = 0.029). The use of clinical features in conjunction with radiological findings provide better diagnostic yields because of overlapping imaging findings.

Pretreatment CT differential diagnosis of tuberculous peritonitis from peritoneal carcinomatosis of advanced epithelial ovarian cancer

Delayed diagnosis of female genital tuberculosis (FGTB) can lead to inappropriate treatment and unnecessary surgical procedures rather than standard anti-TB medication. We tried to evaluate the use of computed tomography (CT) imaging to differentiate TB peritonitis from peritoneal carcinomatosis of advanced epithelial ovarian cancer (AEOC). We investigated women who underwent CT to distinguish between TB peritonitis and peritoneal carcinomatosis of AEOC. We evaluated various CT imaging features to identify differences between the two diseases. In addition, we performed univariate and multivariate logistic regression analyses to identify the independent imaging parameters associated with TB peritonitis and evaluated the diagnostic performance of the combined imaging parameters. We also performed the histopathological analysis of the available salpinx specimens of TB peritonitis. We included 25 women with TB peritonitis and 34 women with peritoneal carcinomatosis of AEOC. A multivariate analysis of the discriminant CT imaging features between the two diseases revealed that changes in fallopian tubes and peritoneal micronodules were independent parameters associated with TB peritonitis (p ≤ 0.012). Combining the two imaging parameters showed an area under the receiver operating characteristic curve of 0.855, a sensitivity of 88.0%, and a specificity of 67.7% for differentiating TB peritonitis from peritoneal carcinomatosis. Furthermore, changes in fallopian tubes were correlated with histopathological abnormalities in salpinx specimens. Pretreatment CT evaluation with useful imaging features could help differentiate TB peritonitis from peritoneal carcinomatosis of AEOC.

The Value of 18F-FDG PET/CT in the Diagnosis of Tuberculous Pleurisy and in the Differential Diagnosis between Tuberculous Pleurisy and Pleural Metastasis from Lung Adenocarcinoma

Objectives

This study aims to investigate the diagnostic value of 18F-FDG PET/CT in tuberculous pleurisy (TBP) and the differential diagnostic value of 18F-FDG PET/CT between TBP and pleural metastasis from lung adenocarcinoma (PMLAC).

Materials and Methods

The features of pleura on PET and hybrid CT were retrospectively studied in 20 patients with TBP and 32 patients with PMLAC. The ROC curve was used to evaluate the diagnostic effectiveness of these indices for TBP and PMLAC, and binary logistic regression analysis was conducted to identify independent predictors of TBP and PMLAC.

Results

There were significant differences in pleural 18F-FDG uptake pattern on PET (P=0.001), pleural morphology pattern on CT (P=0.002), the maximum diameter of the pleural nodule (P=0.001), and interlobular fissure nodule (P=0.001) between TBP and PMLAC groups. The diffused pleural FDG uptake type on PET (odds ratio (OR) = 6.0, 95% CI 2.216–16.248, P=0.001) and the lamellar pleural thickening type on CT (OR = 4.4, 95% CI 2.536–7.635, P=0.001) were independent predictors of TBP, with 60% and 55% sensitivity, 96.6% and 90.6% specificity, and 82.7% and 77.0% accuracy. The combined diagnostic sensitivity, specificity, and accuracy for TBP were 70%, 87.5%, and 80.8%. The mixed pleural FDG uptake type on PET (OR = 5.106, 95% CI 2.024–12.879, P=0.001), the mixed pleural thickening type on CT (OR = 2.289, 95% CI 1.442–3.634, P=0.001), and the maximum diameter of the pleural nodule (OR = 1.027, 95% CI 1.012–1.042, P=0.001) were independent predictors of PMLAC, with 78.1%, 71.9%, and 87.5% sensitivity, 85%, 80%, and 85% specificity, and 80.8%, 75%, and 86.5% accuracy. The combined diagnostic sensitivity, specificity, and accuracy for PMLAC were 96.9%, 85%, and 90.4%.

Conclusions

18F-FDG PET/CT is of great clinical value in the diagnosis of TBP and in the differential diagnosis between TBP and PMLAC.

FDG PET/CT of Primary Ewing Sarcoma of the Peritoneum

ABSTRACT

Ewing sarcoma (ES), which is described as diffuse endothelioma of the bone, is divided into osseous and extraosseous ES mostly affecting children and adolescents. In addition, ES of the peritoneum is rare. We present a case of a 46-year-old man with ES of the peritoneum in whom FDG PET/CT showed high radiotracer activity in the primary tumor.

Clinical features of and diagnostic approaches for abdominal tuberculosis: 5-year experience from a non-tuberculosis-designated hospital in China

BACKGROUND AND PURPOSE

Abdominal tuberculosis (TB) is a common form of extrapulmonary TB but is still a diagnostic dilemma in clinical practice. We are aimed to highlight the clinical features of and diagnostic approaches for abdominal TB.

METHODS

Seventy cases of diagnosed abdominal TB were retrospectively collected at Zhongshan Hospital, Fudan University in Shanghai, China, between 1 August 2015 and 30 June 2020. They were classified as peritoneal TB, lymph node TB, gastrointestinal TB, visceral TB, or mixed TB.

RESULTS

Eighteen patients were diagnosed with peritoneal TB, 9 with lymph node TB, 5 with gastrointestinal TB, 2 with visceral TB, and 36 with mixed TB. Twenty-four patients had only abdominal TB, while 7 had abdominal TB combined with pulmonary TB (PTB), 19 had abdominal TB combined with extrapulmonary TB (EPTB) in one or more sites, and 20 had abdominal TB combined with both PTB and EPTB in other sites. The median diagnosis time was 60 days. Ascites(58.6%), abdominal distension(48.6%), weight loss(44.3%) and fever(42.9%) were the most common symptoms. The overall microbiological and histological confirmation rates were 70.0% and 38.6% respectively. The non-ascites samples yielded a higher microbiological confirmation rate (63.6%) than the total samples (40.8%). Diagnosis was confirmed histologically in 18 patients (69.2%). Forty-five cases (64.3%) were clinically diagnosed. Invasive procedures such as surgery (6/7), percutaneous biopsy (7/7) and endoscopy in lymph node TB (4/5) had high confirmation rates.

CONCLUSIONS

The diagnosis of abdominal TB should be reached by a combination of clinical, laboratorial, radiographic, microbiological and pathological findings.

Characterizing omental PET/CT findings for differentiating tuberculous peritonitis from peritoneal carcinomatosis

PURPOSE

To characterize and investigate PET/CT findings in the omentum in the differentiation of tuberculous peritonitis (TBP) and peritoneal carcinoma (PC).

METHODS

Thirty-nine patients with TBP and 113 patients with PC who underwent PET/CT were retrospectively enrolled. The omental uptake intensity, distribution characteristics, contracture, size and boundary of soft-tissue lesions, and CT patterns were reviewed.

RESULTS

Absent and focal FDG uptake in the lesser omentum was more common in the PC patients (P = 0.034 and P = 0.017, respectively), and diffuse FDG uptake in the lesser omentum was more common in the TBP patients (P < 0.001). An apron-like pattern in the greater omentum commonly occurred in the TBP patients (P = 0.004). Micronodules (< 5 mm) were more common in the TBP patients (P < 0.001), and masses (> 3 cm) were more common in the PC patients (P = 0.001). Smudged and nodular patterns occurred more frequently in the TBP patients than in the PC patients (P < 0.001 and P = 0.003, respectively), and the caked pattern occurred more frequently in the PC patients (P < 0.001). There was no significant difference in the FDG uptake intensity and the boundary of soft-tissue lesions between the TBP and PC patients (P = 0.191 and P = 0.061, respectively).

CONCLUSION

Diffuse FDG uptake, an apron-like pattern, micronodules, and a smudged and nodular pattern might be significant differential features of TBP. Absent and/or focal FDG uptake, mass, and a caked pattern might be significant differential features of PC.

Disseminated tuberculosis mimicking abdominal metastatic carcinoma: A case report

RATIONALE

Extra-pulmonary tuberculosis (TB) has long been a diagnostic challenge for clinicians, often requiring extensive workup and invasive procedures, with the risk of significant complications. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a minimally invasive and highly accurate diagnostic modality for the evaluation of mediastinal and abdominal lymphadenopathy and masses. Several reports on the utility of EUS-FNA as a favorable method for diagnosing extrapulmonary TB have been published.

PATIENT CONCERNS

A 54-year-old man complained of intermittent melena.

DIAGNOSES

18 fluorine-fluorodeoxyglucose positron emission tomography/computed tomography revealed suspected carcinoma metastasis. EUS-FNA did not reveal any evidence of malignancy.

INTERVENTIONS AND OUTCOMES

Laparoscopy was performed, and frozen section pathology during surgery showed granulomas with focal necrosis. Mycobacterium tuberculosis polymerase chain reaction was positive, but acid-fast bacilli staining was negative. Anti-TB treatment was initiated, and the patient was advised to visit the local TB dispensary regularly.

LESSONS

The presence of atypical inflammation of inadequate material or non-representative samples of extra-pulmonary TB was observed on EUS-FNA cytology. Mycobacterium tuberculosis polymerase chain reaction and acid fast bacilli should be performed to diagnose TB because of its higher sensitivity.

Visual PET/CT scoring of mesenteric fdg uptake to differentiate between tuberculous peritonitis and peritoneal carcinomatosis

PURPOSE

We aimed to differentiate tuberculous peritonitis (TBP) from peritoneal carcinomatosis (PC) using a visual positron-emission tomography/computed tomography (PET/CT) scoring system based on mesenteric fluorodeoxyglucose (FDG) uptake.

METHODS

PET/CT scans from 31 patients with TBP and 92 patients with PC were retrospectively reviewed. A visual PET/CT scoring system for mesenteric FDG uptake was used according to the following characteristics: FDG uptake intensity (low = 0, moderate = 1, high = 2), FDG uptake deposits (uniform = 0, irregular = 1, ascitic = 2), FDG uptake focality (diffuse = 0, segmental = 1, focal = 2), nodularity on the corresponding CT (nonnodular = 0, micronodular = 1, macronodular = 2) and mesenteric lymphadenopathy (absent = 0, lymphadenopathy without FDG uptake = 1, lymphadenopathy with FDG uptake = 2). The FDG uptake intensity, deposits, focality, nodularity and mesenteric lymphadenopathy scores between TBP and PC were compared using chi-square tests. The diagnostic performance of this scoring system for differentiating TBP from PC was analyzed using a receiver operating characteristic (ROC) curve. P < 0.05 was considered statistically significant.

RESULTS

Twenty-four patients with TBP (77.4%) and 56 patients with PC (60.9%) had mesenteric FDG uptake (P = 0.095) and were included for evaluation with the visual PET/CT scoring system. PC lesions scored higher than TBP lesions in FDG uptake deposits (P < 0.001), focality (P < 0.001) and nodularity (P < 0.001). No significant differences were observed between PC and TBP lesions in FDG uptake intensity (P = 0.396) and lymphadenopathy (P = 0.074). The total score that combined deposits, focality and nodularity had significant value for differentiating TBP from PC (area under the curve (AUC) = 0.869, P < 0.001), and a cutoff > 1 had a sensitivity (the accuracy for diagnosis of PC) of 80.4% and a specificity (the accuracy for diagnosis of TBP) of 75.0%.

CONCLUSION

A visual PET/CT scoring system based on mesenteric FDG uptake performed well in differentiating between TBP and PC.

The Peritoneum: What Nuclear Radiologists Need to Know

The peritoneum is the largest and most complex serous membrane in the human body. The peritoneal membrane is composed of a layer of mesothelium supported by a thin layer of connective tissue. The peritoneum is one continuous sheet, forming two layers and a potential space between them - the peritoneal cavity- which is subdivided into multiple communicating spaces containing small amount of serous fluid that facilitates frictionless movement of mobile intraabdominal viscera. Peritoneum also contributes to fluid exchange mechanism and plays a role in immune response. The peritoneum is subject to many neoplastic and non-neoplastic processes including infections, trauma, developmental and inflammatory processes. Different Nuclear Medicine imaging techniques can be used to diagnose peritoneal diseases, most of these techniques can be customized depending on the clinical scenario and expected findings. Peritoneal scintigraphy can detect abnormal peritoneal communication or compartmentalization. Several nuclear medicine techniques can help characterize intraperitoneal fluid collections and differentiate sterile from infected fluid. PET imaging plays an important role in imaging of different neoplastic and non-neoplastic peritoneal pathologies. Nuclear radiologists need to be familiar with peritoneal anatomy and pathology to interpret peritoneal findings in dedicated peritoneal nuclear medicine imaging studies, as part of more general nuclear medicine scans, or on CT or MRI component of hybrid imaging studies. The purpose of this article is to review the normal peritoneal anatomy, various pathologic processes involving the peritoneum, and different nuclear medicine and hybrid imaging techniques that can help detect, characterize, and follow up peritoneal pathology.

Abdominal Tuberculosis Mimicking Cancer Clinically and on Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET) Imaging: A Two-Case Series

Case series

Patients: Male, 76-year-old • Male, 53-year-old

Final Diagnosis: Disseminate tuberculosis and liver tuberculoma

Symptoms: Fatigue

Medication: —

Clinical Procedure: —

Specialty: Surgery

Peritoneal Tuberculosis: A Forsaken Yet Misleading Diagnosis

In women presenting with an abdominal mass and ascites, the first diagnosis to consider is ovarian cancer. However, clinicians should always consider alternative differentials, namely, peritoneal tuberculosis, especially in the presence of respiratory symptoms and with the increasing prevalence of extrapulmonary tuberculosis. Peritoneal tuberculosis can mimic the clinical presentation of ovarian cancer, and on imaging, it can show similar features of peritoneal carcinomatosis and nodules. Tumor markers can also be elevated in the absence of malignancy. We present the case of a 44-year-old woman with abdominal distension and ascites. Imaging with CT scan, MRI, and PET scan were inconclusive, showing peritoneal nodules. Cytology of ascites was negative. Laparoscopy was done showing Koch bacilli followed by pulmonary sampling showing Mycobacterium tuberculosis. The patient was treated with quadritherapy with resolution of symptoms.

Predictive value of omental thickness on ultrasonography for diagnosis of unexplained ascites, an Egyptian centre study

Etiology of ascites of unknown origin varies with geographic area and ethnic origin. Tuberculous peritonitis and peritoneal carcinomatosis constitute a considerable proportion of patients. Differentiation between both is a major challenge. The role of omental thickness (OT) by ultrasonography to predict risk of malignancy in unexplained ascites. This prospective study was done at Kasr Alainy School of Medicine, Cairo University and included 100 adults with unexplained ascites and thickened omentum (>15 mm) on ultrasonography. An expert performed ultrasonography to assess peritoneum and peritoneal cavity and measure OT. Ascites was assessed regarding volume, echogenicity, and loculation. The ascitic fluid was analyzed to measure lactate dehydrogenase, adenosine deaminase, and total leukocytic count. Laparoscopic exploration with biopsy was done for final diagnosis that divided the patients into; TB Group (n = 44) and peritoneal carcinomatosis group (n = 56). Main Outcome Measures were to determine degree of omental thickness as a predictor of malignancy risk in unexplained ascites and other ultrasonographic features to predict malignancy risk including omental echogenicity and results of diagnostic ascitic tapping. We found that OT was greater in the PC group compared to the TB group (24.6 ± 4.6 mm vs. 17.9 ± 3.0 mm, respectively, p < 0.001). Higher frequency of hypoechogenicity, irregular peritoneal surface, omental cakes, and lymph nodes was seen in PC Group. ADA, TLC, and relative lymphocyte count were higher in TB group. Omental thickness ≥19.5 mm has a sensitivity of 89.3%, specificity of 84.1% to diagnose PC. We can conclude that omental thickness >19 mm is a sensitive and specific predictor of malignancy in patients with unexplained ascites.

Tuberculosis

Tuberculosis (TB) is currently the world's leading cause of infectious mortality. Imaging plays an important role in the management of this disease. The complex immune response of the human body to Mycobacterium tuberculosis results in a wide array of clinical manifestations, making clinical and radiological diagnosis challenging. ¹⁸F-FDG-PET/CT is very sensitive in the early detection of TB in most parts of the body; however, the lack of specificity is a major limitation. ¹⁸F-FDG-PET/CT images the whole body and provides a pre-therapeutic metabolic map of the infection, enabling clinicians to accurately assess the burden of disease. It enables the most appropriate site of biopsy to be selected, stages the infection, and detects disease in previously unknown sites. ¹⁸F-FDG-PET/CT has recently been shown to be able to identify a subset of patients with latent TB infection who have subclinical disease. Lung inflammation as detected by ¹⁸F-FDG-PET/CT has shown promising signs that it may be a useful predictor of progression from latent to active infection. A number of studies have identified imaging features that might improve the specificity of ¹⁸F-FDG-PET/CT at some sites of extrapulmonary TB. Other PET tracers have also been investigated for their use in TB, with some promising results. The potential role and future perspectives of PET/CT in imaging TB is considered. Literature abounds on the very important role of ¹⁸F-FDG-PET/CT in assessing therapy response in TB. The use of ¹⁸F-FDG for monitoring response to treatment is addressed in a separate review.