Correction to: Nuclear medicine services after COVID-19: gearing up back to normality.

The authors P. Orellana and N. El-Haj were inadvertently deleted in the original paper.

Two decades of SPECT/CT - the coming of age of a technology: An updated review of literature evidence.

PURPOSE: Single-photon emission computed tomography (SPECT) combined with computed tomography (CT) was introduced as a hybrid SPECT/CT imaging modality two decades ago. The main advantage of SPECT/CT is the increased specificity achieved through a more precise localization and characterization of functional findings. The improved diagnostic accuracy is also associated with greater diagnostic confidence and better inter-specialty communication. METHODS: This review presents a critical assessment of the relevant literature published so far on the role of SPECT/CT in a variety of clinical conditions. It also includes an update on the established evidence demonstrating both the advantages and limitations of this modality. CONCLUSIONS: For the majority of applications, SPECT/CT should be a routine imaging technique, fully integrated into the clinical decision-making process, including oncology, endocrinology, orthopaedics, paediatrics, and cardiology. Large-scale prospective studies are lacking, however, on the use of SPECT/CT in certain clinical domains such as neurology and lung disorders. The review also presents data on the complementary role of SPECT/CT with other imaging modalities and a comparative analysis, where available.

Pseudomyxoma peritonei: role of 18F-FDG PET in preoperative evaluation of pathological grade and potential for complete cytoreduction.

INTRODUCTION: For pseudomyxoma peritonei (PMP), survival depends on pathological grade and completeness of cytoreductive surgery. The aim of the study was to assess the ability of preoperative 18F-FDG PET to determine these 2 prognosis indicators. MATERIAL AND METHODS: In this prospective single centre study, all patients presenting with PMP were included. They underwent a preoperative 18F-FDG PET with a double radiological evaluation and an explorative laparotomy with the objective of optimal cytoreduction followed by a hyperthermic intra-operative intraperitoneal chemotherapy (HIPEC). Patients with non resectable disease underwent debulking surgery without HIPEC. The Completeness of Cytoreduction was assessed by CC score. RESULTS: Thirty-four patients were included. PET scanning was positive for 19 patients with grade II (hybrid form) or III (Peritoneal Mucinous Carcinomatosis) and for 2 patients with grade I (disseminated peritoneal adenomucinosis), and negative for 3 patients with grade II - III and for 10 patients with grade I. PET scanning was positive for 6 patients with CC score 2 - 3 and for 16 patients with CC score 0, and negative for 2 patients with CC score 2 - 3 and for 10 patients with CC score 0. The 18F-FDG PET interpretation distinguished 2 patients groups (grade I and grade II - III) with a sensitivity of 90% and a specificity of 77%. Moreover, probability of complete cytoreduction when PET was negative was over 80%. CONCLUSION: Preoperative 18F-FDG PET may predict pathological grade and completeness of cytoreduction which are the two main prognostic factors in patients with PMP.

MRI evaluation of bulky tumor masses in the mesentery and bladder involvement in peritoneal carcinomatosis.

AIM: Peritonectomy procedures with intraperitoneal chemohyperthermia are an effective but costly treatment for peritoneal carcinomatosis (PC). Consequently a proper selection of patients is necessary. We evaluated the benefit of MRI prior to surgery, in the detection of two of the main surgery contraindications: bulky mesenteric tumors and bladder implants. METHODS: Three experts retrospectively reviewed abdominal and pelvic MRI from 19 cases of surgically proved PC (ovary: 7; colorectal: 7; gastric: 2; pseudomyxoma peritonei: 2; appendix: 1). RESULTS: Mesenteric tumors were always identified as hypersignal masses on axial and coronal fat suppression gadolinium-enhanced T1 images (n=3). Three out of five bladder implants were detected. The two cases of bladder implants that were not detected on MRI were missed because the bladder was not filled. The best sequence for the detection of bladder involvement was axial T2-weighted images with bladder filling. CONCLUSIONS: Evaluating the preoperative resectability of PC is crucial for patient management. MRI seems to reliably detect bulky mesenteric tumors and bladder implants on condition the bladder is filled and appropriate sequences are used.

Assessment of tumour response to chemotherapy for metastatic colorectal cancer: accuracy of the RECIST criteria.

Evaluation of tumour size modifications in response to treatment is a critical issue in the management of advanced malignancies. In 1981, the World Health Organization (WHO) established guidelines for tumour response assessment. These WHO1981 criteria were recently simplified in a revised version, named RECIST (Response Evaluation Criteria in Solid Tumours), which uses unidimensional instead of bidimensional measurements, a reduced number of measured lesions, withdrawal of the progression criteria based on isolated increase of a single lesion, and different shrinkage threshold for definitions of tumour response and progression. In order to validate these new guidelines, we have compared results obtained with both classifications in a prospective series of 91 patients receiving chemotherapy for metastatic colorectal cancer. Data from iterative tomographic measurements were fully recorded and reviewed by an expert panel. The overall response and progression rates according to the WHO1981 criteria were 19% and 58%, respectively. Using RECIST criteria, 16 patients were reclassified in a more favourable subgroup, the overall response rate being 28% and the progression rate 45% (non-weighted kappa concordance test 0.72). When isolated increase of a single measurable lesion is not taken into account for progression with the WHO1981 criteria, only 7 patients were reclassified and the kappa test was satisfying, i.e. > or =0.75, for the whole population as well as for each of the responding and progressive subgroups. Since it provides concordant results with a simplified method, the use of RECIST criteria is recommended for evaluation of treatment efficacy in clinical trials and routine practice.

[General review of the value of hepatic MRI in the diagnosis and preoperative staging of liver metastasis from colon and rectum cancer]. / Intérêt de l'IRM hépatique dans le diagnostic et le bilan préopératoire des métastases hépatiques des cancers colo-rectaux.

Hepatic resection of secondary liver neoplasms is currently the only potentially curative therapy for patients with primary colorectal carcinoma. Long-term survival is closely related to stage, regardless of the number, size and distribution of liver lesions. Preoperative detection of liver metastases is crucial in patient staging and imaging techniques must be as accurate as possible to evaluate whether hepatic resection can be performed. Among the various strategies applied to the preoperative detection of liver metastases, CT with intra-arterial portography (CTAP) has been found to be the most sensitive technique. It is an invasive evaluation with a reported sensitivity ranging from 81 to 94% but with 6 to 15% of false-positive results. Recent studies demonstrate that MRI with superparamagnetic iron oxide has an equivalent sensitivity and specificity to CTAP. This paper reviews the technique of MRI, evaluates its sensitivity and specificity, and presents the advantages and draw backs of the technique.

Sclerosing cholangitis in adults with cystic fibrosis: a magnetic resonance cholangiographic prospective study.

BACKGROUND/AIMS: Liver disease is a leading cause of morbidity in adult patients with cystic fibrosis. Diagnosis of limited liver involvement in asymptomatic patients is important since a safe and effective treatment with ursodeoxycholic acid can be used. We carried out a prospective open study to describe the intrahepatic biliary lesions using magnetic resonance cholangiography. METHODS: Twenty-seven adult patients with cystic fibrosis were prospectively enrolled, whatever their hepatobiliary status. All patients underwent liver function tests, ultrasonography and magnetic resonance cholangiography. Magnetic resonance cholangiograms were acquired on a Philips 1.5 Tesla unit using a 3D TSE MR sequence. Acquisition parameters (120 slices, 1.6 mm thickness, interslice overlap 0.8 mm) were followed by MIP reconstruction in two orthogonal planes. Magnetic resonance cholangiography images were assessed for the presence of stenosis, dilatations and rigidity corresponding to current criteria of cholangitis. Among the 27 cystic fibrosis patients, 18 (Group I) fulfilled none of the clinical, biological or ultrasonographic criteria of liver disease; the remaining nine (Group II) fulfilled the criteria for liver disease. In every patient, current causes of secondary sclerosing cholangitis had been excluded. RESULTS: All the Group II patients had abnormal magnetic resonance cholangiograms with features resembling those of primary sclerosing cholangitis in five, and simple biliary lesions in four. Nine Group I patients had abnormal magnetic resonance cholangiograms with primary sclerosing cholangitis-like lesions in five and simple biliary lesions in four. Magnetic resonance cholangiography anomalies were always dilatations, either isolated or associated with strictures and rigidity, both resembling those seen in cholangitis. They were seen in all the patients with known liver disease and in half the patients without evidence of liver disease. CONCLUSION: This study confirms the high frequency of intrahepatic biliary abnormalities in CF patients, which is probably underestimated by clinical, biological and ultrasonographic evaluation. The magnetic resonance cholangiography technique could be useful to detect early intrahepatic biliary tract involvement in cystic fibrosis patients.

Magnetic resonance cholangiopancreatography: interest of IV secretin administration in the evaluation of pancreatic ducts.

The aim of this study was to investigate whether IV secretin administration is useful to enhance the delineation of the main pancreatic duct (MPD) and its side branches, and if it provides additional information concerning signal voids and strictures. Twenty-seven patients referred for abdominal pain or laboratory abnormalities (group 1, n = 13) or for the follow-up of chronic pancreatitis (CP; group 2, n = 14) were studied. Magnetic resonance cholangiopancreatography was acquired at 1.5 T before and after IV secretin by a coronal 3D TSE T2-weighted sequence with maximum intensity projection postprocessing. In group 1 secretin provided a better visualization of MPD in 9 patients. In a patient with pancreas divisum, it allowed suggestion of stenosis of the accessory papilla, confirmed at endoscopic retrograde cholangiopancreatography (ERCP). In group 2 secretin provided a better visualization of MPD only in the 3 patients with mild disease. A mild dilation upstream a stricture occurred in 2 cases and a marked dilation appeared upstream a wallstent which was non-patent at ERCP. Few changes were noticed concerning side branches. These preliminary results indicate that in patients without CP, secretin improves MPD delineation avoiding invasive diagnostic ERCP. In patients with mild CP secretin does not improve the characterization of signal voids, but it may be useful to appreciate their significance and to follow-up stenosis.