Although prostate-specific membrane antigen (PSMA) PET/CT has been shown valuable for staging biopsy-proven [B(+)] high-risk prostate cancer, elderly patients are occasionally referred for PSMA PET/CT without a preimaging confirming biopsy [B(-)]. The current study evaluated the rate, clinical characteristics, and PET-based stage of elderly B(-) patients and explored whether biopsy status affects therapeutic approach. Methods: One hundred consecutive patients at least 80 y old who underwent staging 68Ga-PSMA-11 PET/CT were included. For each patient, we documented whether preimaging biopsy was performed, the clinical parameters, the PET-based staging parameters, and the primary therapy received. Results: Thirty-four (34%) of the elderly patients included in the study had no preimaging biopsy. Compared with B(+) patients, B(-) patients were older (median age, 87 vs. 82 y; P < 0.01), with worse performance status (P < 0.01) and higher prostate-specific antigen (PSA) levels (median, 57 vs. 15.4 ng/mL; P < 0.01). On 68Ga-PSMA-11 PET/CT, all B(-) patients had avid disease, with trends toward higher rates of bone metastases (47.1% vs. 28.8%) and overall advanced disease (50% vs. 33.3%) than in B(+) patients. Among patients with localized (n = 36) or locally advanced (n = 25) disease, B(-) patients were less commonly referred than B(+) patients for definitive therapies (P < 0.01). However, higher age, Eastern Cooperative Oncology Group performance status, and PSA were other probable factors determining their therapeutic approach. Among 39 patients with advanced disease, 38 received hormonal therapy irrespective of their biopsy status. Among B(-) patients with advanced disease who were referred for hormonal therapy, 12 of 13 with follow-up data showed a biochemical or imaging-based response. Conclusion: Real-life experience with 68Ga-PSMA-11 PET/CT indicates that around one third of elderly patients are referred for imaging without a preimaging confirming biopsy. These patients are likely to be older, with a worse clinical status and higher PSA levels. Advanced disease might be more likely to be identified on their 68Ga-PSMA-11 PET/CT images, and if it is, their biopsy status does not preclude them from receiving hormonal therapy.
Topic: 26. Sickle cell disease Background: Townes and Berkeley mouse models of sickle cell disease (SCD) are commonly used to study disease pathophysiology and to develop novel therapies. Despite similar pathophysiology to SCD patients, there are distinctive differences. For example, Townes HbSS mice have higher ATP and lower 2,3-diphosphyglycerate (2,3-DPG) levels compared to HbAA mice. This contrasts with SCD patients, who show high 2,3-DPG but low ATP, suggesting potential differences between human and murine red blood cell (RBC) metabolism. Pyruvate kinase (PK), a key ATP-generating enzyme in glycolysis, is a target for novel SCD therapies. While PK activators have been shown to increase hemoglobin in clinical trials, such treatments do not always lead to the same hematological change in mouse models, further suggesting that PK features may differ between SCD mouse models and human patients. A detailed characterization of PK and related important cellular metabolites in murine SCD models and SCD patients is therefore important. Aims: To study PK features in murine and human SCD RBCs. Methods: Wild-type (C57BL/6J), Townes and Berkeley mice (non-sickling and sickling) were studied. Human blood was obtained from healthy controls (HbAA) and untreated SCD patients (HbSS). Hematological parameters were measured using the Cell-Dyn Sapphire (Abbott Diagnostics). PK and hexokinase (HK) activity, and PK thermostability (53°C) were measured on purified RBCs. Levels of ATP, 2,3-DPG, and reduced glutathione (GSH) were measured by LC-MS/MS and spectrophotometry, respectively. Results: Samples from 12 wild-type mice, 13 Townes mice (6 HbAA, 7 HbSS), 6 Berkeley mice (3 non-sickling, 3 sickling) and 10 human subjects (6 HbAA, 4 HbSS) were included. High reticulocyte counts compared to control mice were observed in both Townes and Berkeley SCD mice (median 59% and 48% compared to 7% and 5%, respectively). This was accompanied by an increased activity of PK in both SCD models (Figure 1A). When normalizing PK activity to that of HK, another age-dependent enzyme, no difference was found between sickling and non-sickling mice for both mouse models (Figure 1B). However, PK/HK ratio was lower in the Berkeley mice compared to Townes mice (p<0.01 for both non-sickling and sickling mice). ATP/2,3-DPG ratio was higher in Townes and Berkeley sickling mice compared to their control mice (Figure 1C; p<0.01). This contrasts with humans where healthy controls had higher ATP/2,3-DPG ratio than SCD patients (p<0.05). Surprisingly, mouse RBC PK was considerably less stable than its human counterpart, as reflected by a strikingly decreased thermostability (Figure 1D). GSH levels were significantly increased in both Townes and Berkeley sickling mice compared to non-sickling mice, which is in contrast with previous findings that SCD patients have lower GSH levels. Summary/Conclusion: PK/HK ratios are similar between sickling and non-sickling mice in both Berkeley and Townes model strains. In both models, however, there are significant changes in energy level (ATP), 2,3-DPG (important for oxygen affinity), and antioxidant level (GSH) when compared sickling to non-sickling mice. Our results further reveal important distinctions between mouse models and humans: the lack of PK/HK ratio difference between sickling and non-sickling mice, and overall lower PK thermostability in mice. Sickling mice also have higher ATP/2,3-DPG ratio and GSH levels, which is very different from SCD patients. These differences should be considered when studying PK activators in SCD mouse models and extrapolating results to a clinical response.Keywords: Transgenic mice, Pyruvate kinase, Sickle cell disease
Internal hernias are an uncommon cause of small bowel obstruction. Paraduodenal hernias have been considered until recently the most common sub-type. Due to non-specific and intermittent signs and symptoms the diagnosis of these hernias is notoriously difficult. We report a case of a paraduodenal hernia diagnosed correctly with abdominal computed tomography that was confirmed at surgery and review the clinical and imaging findings of these hernias.
Abstract Background[ 18 F]-Fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) may sometimes be suboptimal for imaging gastric adenocarcinoma. The recently introduced [ 68 Ga]Ga-FAPI-04 (FAPI) PET/CT targets tumor stroma and has shown considerable potential in evaluating the extent of disease in a variety of tumors.MethodsWe performed a head-to-head prospective comparison of FAPI and FDG PET/CT in the same group of 13 patients with gastric adenocarcinoma who presented for either initial staging (n = 10) or restaging (n = 3) of disease. Lesion detection and maximum standardized uptake value (SUV max ) were compared between the two types of radiotracers.ResultsAll ten primary gastric tumors were FAPI-positive (100% detection rate), whereas only five were also FDG-positive (50%). SUV max was not significantly different, but the tumor-to-background ratio was higher for FAPI (mean, median, and range of 4.5, 3.2, and 0.8-9.7 for FDG and 12.9, 11.9, and 2.2-23.9 for FAPI, P = 0.007). The level of detection of regional lymph node involvement was comparable. FAPI showed a superior detection rate for peritoneal carcinomatosis (100% vs. none). Two patients with widespread peritoneal carcinomatosis underwent a follow-up FAPI scan after chemotherapy: one showed partial remission and the other showed progressive disease.ConclusionsThe findings of this study suggest that FAPI PET/CT outperforms FDG PET/CT in detecting both primary gastric adenocarcinoma and peritoneal carcinomatosis from gastric cancer. FAPI PET/CT also shows promise for monitoring response to treatment in patients with peritoneal carcinomatosis from gastric cancer, however, larger trials are needed to validate these findings.
Ga-prostate-specific membrane antigen positron emission tomography/computerized tomography (Ga-PSMA PET/CT) is part of the initial workup of patients with intermediate and high-risk prostate cancer provided by the Israeli national health services.To assess the incidence of metastatic spread in consecutive patients with newly diagnosed cancer, and the potential added value of Ga-PSMA PET/CT to the staging imaging algorithm.Patients with newly diagnosed intermediate- and high-risk prostate cancer were referred for initial staging by Ga-PSMA PET/CT between May 2016 and April 2017. Blood prostate-specific antigen (PSA) levels, clinical history, imaging reports and histopathological reports (including Gleason scores) were obtained. Maximal standardized uptake values (SUVmax) were determined for the primary lesions detected within the prostate.The study included 137 consecutive patients with intermediate- and high-risk disease who underwent Ga-PSMA PET/CT staging. Of these, 75 had Ga-PSMA uptake in both prostate lobes, 57 had unilateral uptake, and 5 patients had no uptake. SUVmax in the primary tumor correlated significantly with PSA levels. Thirty-five patients had increased uptake compatible with metastatic disease involving lymph nodes, bone, and viscera. Twenty-seven patients had available bone scintigraphy results: 18 (69%) of their 26 bone metastases detected by Ga-PSMA PET/CT were missed on bone scintigraphy.Ga-PSMA PET/CT shows promise as a sole whole-body imaging modality for assessing the presence of soft tissue and bone metastases in the setting of prostate cancer.
CT evaluation of appendicitis represents an increasingly common emergency room request. While the overall accuracy of CT is high, numerous pitfalls exist which may deceive radiologists, resulting in a missed diagnosis of appendicitis. The inflamed appendix may be unusual in its location, or may appear normal if only a small portion of the distal appendix is involved (tip appendicitis). In a patient with a history of appendectomy, inflammation of the appendiceal stump may be easily missed. Appendicitis may closely mimic small bowel obstruction, or gynaecological disease, especially after perforation has occurred. Even a misleading clinical history may lead the radiologist's eye astray. This pictorial review demonstrates these and other potential radiological pitfalls, and includes important points for the accurate diagnosis of appendicitis.
To assess the prevalence and significance of arteriovenous fistulae after prostate biopsy, we performed color Doppler ultrasonography immediately after 136 consecutive transrectal prostate needle biopsies. Pathologic results were correlated with color Doppler ultrasonographic findings. Arteriovenous fistulae developed after 17 biopsies (13%), all closed spontaneously within 18 minutes, and none were associated with unusual bleeding. Carcinoma was noted in 25 biopsy specimens (18%), 10 (40%) of which were followed by arteriovenous fistula. The correlation between malignancy and postbiopsy arteriovenous fistula was statistically significant (P < 0.0004), consistent with hypervascularity known to be present in many prostate cancers.
To assess diagnostic accuracy of combined positron emission tomography (PET) and computed tomography (CT) in detection of pelvic recurrence in patients with rectal cancer who underwent abdominoperineal or anterior resection.Sixty-two patients were enrolled; 37 were men, and 25 were women. Seventeen patients underwent abdominoperineal resection and 45 underwent anterior resection with an anastomosis in the pelvic region before referral for PET/CT. Pelvic sites of fluorine 18 ((18)F) fluorodeoxyglucose (FDG) uptake were rated separately on PET and PET/CT images as benign or malignant on the basis of shape, location, and intensity of (18)F FDG uptake (1-2 = benign and/or physiologic, 3 = equivocal, 4-5 = malignant). Two readers interpreted images in consensus. Altered pelvic anatomy and presence of presacral abnormalities were assessed with CT. Pelvic recurrence was confirmed with histologic analysis or clinical and imaging follow-up. Sensitivity, specificity, positive and negative predictive values, and accuracy of PET and PET/CT in the detection of pelvic recurrence were compared with lesion- and patient-based analyses by using the chi(2) test. Clinical relevance of PET/CT assessment was determined.Of 81 pelvic sites with increased (18)F FDG uptake, 44 were malignant. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for differentiating malignant from benign (18)F FDG uptake in the pelvis were 98%, 96%, 90%, 97%, and 93% for PET/CT and 82%, 65%, 73%, 75%, and 74% for PET, respectively. The most common cause for false-positive interpretation of PET findings was physiologic (18)F FDG uptake in displaced pelvic organs. Presacral CT abnormalities were present in 30 (48%) of 62 patients, and seven (23%) abnormalities were malignant. PET/CT was used to distinguish benign and malignant presacral abnormalities with a sensitivity, specificity, positive predictive value, and negative predictive value of 100%, 96%, 88%, and 100%, respectively. PET/CT findings were clinically relevant in 29 (47%) of 62 patients.PET/CT is an accurate technique in the detection of pelvic recurrence after surgical removal of rectal cancer.
