To Enhance or Not to Enhance? The Role of Contrast Medium 18F-FDG PET/CT in Recurrent Ovarian Carcinomas.

Background and Objectives: 18F-fluorodeoxyglucose (FDG) positron emission tomography/X-ray computed tomography (PET/CT) represents the mainstay diagnostic procedure for suspected ovarian cancer (OC) recurrence. PET/CT can be integrated with contrast medium and in various diagnostic settings; however, the effective benefit of this procedure is still debated. We aimed to compare the diagnostic capabilities of low-dose and contrast-enhanced PET/CT (PET/ldCT and PET/ceCT) in patients with suspected ovarian cancer relapse. Materials and Methods: 122 OC patients underwent both PET/ldCT and PET/ceCT. Two groups of nuclear medicine physicians and radiologists scored the findings as positive or negative. Clinical/radiological follow-up was used as ground truth. Sensitivity, specificity, negative/positive predictive value, and accuracy were calculated at the patient and the lesion level. Results: A total of 455 and 474 lesions were identified at PET/ldCT and PET/ceCT, respectively. At the lesion level, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were not significantly different between PET/ldCT and PET/ceCT (98%, 93.3%, 97.4%, 94.9%, and 96.9% for PET/ldCT; 99%, 95.5%, 98.3%, 97%, and 98% for PET/ceCT, p = ns). At the patient level, no significant differences in these parameters were identified (e.g., p = 0.22 and p = 0.35 for accuracy, in the peritoneum and lymph nodes, respectively). Smaller peritoneal/lymph node lesions close to physiological FDG uptake sources were found in the cases of misidentification by PET/ldCT. PET/ceCT prompted a change in clinical management in four cases (3.2%) compared to PET/ldCT. Conclusions: PET/ceCT does not perform better than PET/ldCT but can occasionally clarify doubtful peritoneal findings on PET/ldCT. To avoid unnecessary dose to the patient, PET/ceCT should be excluded in selected cases.

Imaging findings of ovarian leiomyosarcoma with histopathologic correlations.

Leiomyosarcoma (LMS) is a malignant mesenchymal tumor deriving from smooth muscle. Ovarian LMS is exceedingly rare and only few reports have been reported in literature. The article illustrates a case of ovarian leiomyosarcoma in a 61-year-old woman, describing CT and MRI features correlated to histopathologic findings. LMS should be included in the differential diagnosis of solid and multiloculated ovarian lesions, in particular in post-menopausal women.

Comparison of computed tomography and magnetic resonance imaging in the discrimination of intraperitoneal and extraperitoneal rectal cancer: initial experience.

OBJECTIVES: To compare computed tomography (CT) and magnetic resonance imaging (MRI) in evaluation of intraperitoneal/extraperitoneal location of rectal cancers. METHODS AND MATERIALS: We assessed the identification of the anterior peritoneal reflection (APR) and the distance from the inferior edge of tumors to the anal verge and from the APR to the anal verge. RESULTS: Distances obtained with CT and MRI showed a strong correlation [Spearman's coefficient of rank correlation (rho): 0.995; P<.0001]. Magnetic resonance showed sensitivity of 100% (95% CI: 89.62-100.00%), specificity of 75% (95% CI: 20.34-95.88%), positive predictive value (PPV) of 97.14% (95% CI: 85.03-99.52%), and negative predictive value (NPV) of 100% (95% CI: 30.48-100.00%). CT showed a sensitivity of 100% (95% CI: 89.32-100.00%), specificity of 60% (95% CI: 15.40-93.51%), PPV of 94.29% (95% CI: 80.81-99.13%), and NPV of 100% (95% CI: 30.48-100.00%). CONCLUSIONS: CT demonstrated a potential supporting role in the evaluation of rectal cancer, showing a strong correlation with MRI.

Giant cell arteritis: a systematic review of the qualitative and semiquantitative methods to assess vasculitis with 18F-fluorodeoxyglucose positron emission tomography.

Giant cell arteritis (GCA) is the most common vasculitis affecting medium and large vessels. It shows a close clinical association with polymyalgia rheumatica (PMR), a musculoskeletal inflammatory disorder, which is clinically characterized by girdles pain and stiffness. 18F-Fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) is an effective tool for the diagnosis, grading, and follow-up of patients affected by GCA involving the aorta and its proximal branches, but the lack of a standardized method for the assessment of vascular inflammation remains a critical issue, potentially leading to misclassification. In our systematic review, including 19 original articles for a total of 442 GCA patients (with or without PMR symptoms) and 535 healthy controls, we described the different qualitative, semiquantitative and combined methods that have been proposed throughout the literature for assessing the presence and grading the severity of GCA-related vascular inflammation on 18F-FDG PET scans, focusing on the diagnostic performance and examining their respective advantages and limitations. The majority of the included studies adopted qualitative methods of PET image analysis, which are less sensitive but more specific than semiquantitative ones. Among the semiquantitative approaches, the aortic-to-blood pool uptake ratio of the aortic arch seems to be the most accurate method.

CT of the abdomen: degree and quality of enhancement obtained with two concentrations of the same iodinated contrast medium with fixed iodine delivery rate and total iodine load.

OBJECTIVES: to compare vascular and parenchymal enhancement in abdominal computed tomography (CT) using two iodine concentrations (370 vs 300mgI/mL) of the same contrast medium (CM) molecule (iopromide), using fixed iodine delivery rate (IDR, 1.2gI/s) and total iodine load (630mgI/kg). METHODS: 144 patients were randomized into two groups: group A receiving iopromide 370 and group B receiving iopromide 300. Attenuation values (AV) were measured in correspondence to key anatomical structures on different phases and compared between groups with parametrical tests. Qualitative analysis was also performed. Peak injection pressure and local discomfort at the site of injection (pain and warmth) were registered. RESULTS: mean AV of abdominal aorta in late arterial phase were 300.32±59.76 for group A and 298.2±59.14 for group B (p=0.8); mean AV of portal vein in portal phase were 190.5±29.92 for group A and 192.91±24.12 for group B (p=0.6). Mean AV of liver parenchyma in portal phase were 124.73±18.22 for group A and 125.11±15.7 for group B (p=0.9); mean AV of liver at equilibrium were 85.11±7.75 for group A and 85.41±8.09 for group B (p=0.8). Qualitative analysis did not show significant differences between groups (p>0.05). Median peak injection pressure was lower in group B (93psi, 76-172) than in group A (115psi, 88-288, p<0.0001), while discomfort at injection site was not significantly different (p>0.05). CONCLUSIONS: with fixed IDR and total iodine load, comparable quantitative and qualitative enhancement can be achieved with different concentrations of the same CM. Peak injection pressure increases using CM with higher iodine concentration.

Crohn's disease: value of diagnostic imaging in the evaluation of anastomotic recurrence.

UNLABELLED: In patients who had previously undergone ileocolic resection due to Crohn's disease (CD) complications, anastomotic recurrence is a frequent event, which may lead to further surgical interventions. Optical colonoscopy with retrograde ileoscopy is currently the reference standard technique to confirm the clinical suspicion of anastomotic recurrence; however, the ileal side of ileocolic anastomoses may not be assessed due to technical complexities in approximately 1/3 of cases. Moreover, endoscopy allows for an investigation limited to the mucosal surface without demonstrating trans-mural involvement and/or penetrating complications (i.e. fistulas and abscesses). Imaging plays an important role in the assessment of both ileocolic and entero-enteric anastomoses in patients with CD. Conventional radiological methods (i.e. small bowel enteroclysis and small bowel follow through) can effectively depict the presence of aphthous ulcers and other mild and subtle mucosal abnormalities, but they are not precise for the diagnosis of transmural and extramural disease. CT - and MR- enterography accurately demonstrate both the extent of bowel wall involvement and the presence of penetrating complications. The main cross-sectional imaging findings observed in CD (including anastomotic recurrence) are small bowel wall thickening with bilaminar or trilaminar stratification, hyperdensity and oedema of the mesenteric fat, engorged mesenteric vasa recta ("comb sign"), sub-mucosal fibro-fatty infiltration and mesenteric adenopathy. Ultrasonography performed after distension of small bowel loops with anechoic contrast agents (Small Intestine Contrast Ultrasonography - SICUS -) is a non-invasive imaging technique which can detect early inflammatory alterations of the anastomosis. On the other hand ultrasonography is an operator-dependent technique and it lacks of a large anatomic field of view. KEY WORDS: Computed Tomography enterography, Crohn's disease, Ileocolic anastomosis, Magnetic Resonance Imaging.

Crohn's disease recurrence in patients with ileocolic anastomosis: value of computed tomography enterography with water enema.

OBJECTIVES: The main objective of the present work was to determine the diagnostic value of CT-enterography with water enema (CTe-WE) in the assessment of the ileocolic anastomosis in patients with Crohn's disease (CD). The prevalence of synchronous inflammatory lesions (SILs) involving gastrointestinal segments distinct from the anastomosis was also determined. Further, the association between the type of ileocolic anastomosis and the behavior (i.e. inflammatory, stricturing, penetrating) of CD recurrence was evaluated. METHODS: 51 patients were retrospectively included (26 [51%] male and 25 [49%] female; mean age: 52.88 years ± 13.35). Ileocolic anastomoses were: 18 (35.3%) stapled side-to-side, 17 (33.3%) end-to-side, and 16 (31.4%) end-to-end. CTe-WEs were reviewed in consensus by two gastrointestinal radiologists. Endoscopy and medical records were used as reference standards. RESULTS: CTe-WE yielded 95.35% sensitivity (CI 95%: 84.19-99.43%), 75.00% specificity (CI 95%: 34.91-96.81%), and 92.15% diagnostic accuracy (CI 95%: 81.31-98.02%). Anastomotic recurrence was found in 41/51 (80.4%) patients, including 30/41 (73.2%) cases of isolated anastomotic recurrence, and 11/41 (26.8%) cases of anastomotic recurrence with a SIL. A significant lower prevalence of stricturing recurrence was observed in patients with stapled side-to-side anastomoses (p=0.033). CONCLUSIONS: CTe-WE provides a good distension of both sides of ileocolic anastomoses allowing the detection of SILs.