Gaetane Ceulemans

Can 18-FDG-PET during radiotherapy replace post-therapy scanning for detection/demonstration of tumor response in head-and-neck cancer?

PURPOSE In routine practice, the tumor response in head-and-neck cancer (HNC) is assessed 3-4 months after radiotherapy (RT). We compared the results of fluorodeoxyglucose-positron emission tomography (FDG-PET) during (47 Gy) and 4 months after RT. METHODS AND MATERIALS In 40 patients with HNC, PET was performed before (PET1), at the end of Week 4 (47 Gy) (PET2), and 4 months after RT (PET3). Visual analysis classified patients as having a complete response (CR) or a non-CR (NCR). The sensitivity, specificity, accuracy, negative predictive value, and positive predictive value for PET2 and PET3 were determined. The 2-year overall survival (OS) rate for a CR and NCR was calculated for both response evaluation points. RESULTS After a median follow-up of 26 months, 10 patients had died, 6 had residual disease, and 24 remained disease free. The overall sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of PET2 vs. PET3 for the detection of a CR was 28.6%, 81.8%, 31.0%, 80.0%, and 42.5% vs. 78.6%, 75.0%, 60.0%, 88.0%, and 77.5%, respectively. The 2-year OS rate determined at 47 Gy was 90.0% and 71.8% for a CR and NCR, respectively, and did not appear to be significantly different (p = .50). For the study, at 4 months, the OS was significantly better in the CR group (91.8%) than in the NCR group (49.9%; p = .0055). CONCLUSION The high specificity and positive predictive value for the evaluation of tumor response with PET2 and PET3 might avoid unnecessary salvage surgery in patients with a CR. In contrast to PET3, the sensitivity of PET 2 was low, and the difference in OS between the CR and NCR groups was not significantly different. Therefore, the evaluation of the tumor response with FDG-PET at 4 months after RT completion cannot be replaced by FDG-PET during RT at 47 Gy.

Can 18F-FDG-PET response during radiotherapy be used as a predictive factor for the outcome of head and neck cancer patients?

ObjectivesWe investigated if (18F) fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) during radiotherapy or concurrent chemoradiotherapy adds information about the treatment outcome compared with an 18FDG-PET study before treatment. MethodsForty-three patients with head and neck cancer were treated with helical tomotherapy. 18F-FDG-PET was performed at baseline and during the treatment after 47 Gy. Tracer accumulation at the tumor site was assessed visually and semiquantitatively using the maximal standardized uptake values (SUVmax). With median SUVmax of both the studies as cutoff, patients were categorized into low and high SUVmax groups. For visual analysis, two independent observers classified patients as complete metabolic responders (CMR) or noncomplete metabolic responders (NCMR). ResultsAt baseline the median SUVmax was 8.11 (2.41–15.13). The overall survival (OS) and disease-free survival (DFS) were 81 and 67% versus 50 and 40% for the low and high SUVmax, respectively. OS was significantly different (P=0.027). During therapy, median SUVmax was 4.03 (1.94–7.58). OS and DFS were 82 and 63%, versus 47 and 42% for the low and high SUVmax group, respectively. OS was significantly different (P=0.026). No significant differences between CMR versus NCMR in OS (72 vs. 60%), and DFS (56 vs. 49%) were found. ConclusionCategorizing patients on the basis of a semiquantitative approach resulted in significant differences in OS for both the scans before and during therapy. Future work on a larger number of patients is warranted to determine SUVmax cutoff values which could be used for the early identification of patients with poor treatment outcome or perhaps other therapeutic approaches.

Prediction of response to neoadjuvant radiotherapy in patients with locally advanced rectal cancer by means of sequential 18FDG-PET.

PURPOSE Morphologic imaging techniques perform poorly in assessing the response to preoperative radiotherapy (RT), mainly because of desmoplastic reactions. The aim of this study was to investigate the potential of sequential 18-fluoro-2-deoxy-d-glucose (18FDG-PET) in assessing the response of rectal cancer to neoadjuvant RT and to determine which parameters can be used as surrogate markers for histopathologic response. METHODS AND MATERIALS 18FDG-PET scans were acquired before and during the 5th week after the end of RT. Tracer uptake was assessed semiquantitatively using standardized uptake values (SUV). The percentage differences (%Δ) between pre- and post-RT scans in SUV(max), SUV(mean), metabolic volume (MV), and total glycolytic volume (tGV) were calculated. RESULTS Forty-five consecutive patients with histologically confirmed rectal adenocarcinoma were enrolled. After neoadjuvant RT, 20 of the 45 patients were classified as histopathologic responders and 25 as non-responders. Intense 18F-FDG uptake was seen in all tumors before neoadjuvant RT (average SUV(max) 12.9 ± 6.0). When patients were classified as histologic responders and nonresponders, significant differences in %ΔSUV(max) (55.8% vs. 37.4%, p = 0.023) and %ΔSUV(mean) (40.1% vs. 21.0%, p = 0.001) were observed between the two groups. For %ΔMV and %ΔtGV, decreases were more prominent in responders but were not significantly different from those in nonresponders. As demonstrated by receiver operating characteristic analysis, %ΔSUV(mean) was a more powerful discriminator than was %ΔSUV(max). The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value for optimal threshold of %ΔSUV(mean) (24.5%) were 80%, 72%, 76%, 70%, and 82% respectively. CONCLUSION Sequential 18FDG-PET allows assessment of the response to preoperative RT. Both %ΔSUV(mean) and %ΔSUV(max) correlate with histopathologic response and can be used to evaluate and compare the effectiveness of different neoadjuvant treatment strategies. The maximum accuracy figures and the positive predictive value figures for both Δ%SUV(mean) and Δ%SUV(max) are, however, too low to justify modification of the standard treatment protocol of an individual patient.

Complete right-to-left shunt on lung perfusion SPECT results in the detection of a persistent left vena cava superior draining to the left atrium

In order to exclude acute pulmonary embolism, a lung perfusion scintigraphy was performed in a 53-year-old male, with a history of Fallot’s tetralogy. He had been immobilized because of a tibial fracture and complained of worsening chest pain and dyspnea.

The role of diffusion-weighted MR imaging and ADC values in the diagnosis of gastric tumors.

In order to exclude acute pulmonary embolism, a lung perfusion scintigraphy was performed in a 53-year-old male, with a history of Fallot’s tetralogy. He had been immobilized because of a tibial fracture and complained of worsening chest pain and dyspnea.

Extrastriatal uptake on I-123-ioflupane brain SPECT

DaTSCAN® is a solution of I-ioflupane (I-FP-CIT), a cocaine analogue with high binding affinity for presynaptic dopamine transporters (DaT), in particular in the striatal region of the brain, suitable for SPECT imaging. It is mainly indicated for detecting loss of functional dopaminergic neuron terminals in the striatum in patients with clinically uncertain parkinsonian syndromes in order to help differentiate essential tremor from parkinsonian syndromes [1, 2]. A 72-year-old woman, with a history of tremor and postural hypotension, was admitted to our hospital because of a fall with crush syndrome. I-FP-CIT SPECT was performed and demonstrated besides normal dopaminergic activity in the striatum (a) focal extracerebral tracer uptake in the right temporal region (b). Correlation of the Iioflupane scan with MRI of the brain localized the extracerebral I focus in the right temporal muscle corresponding to an intramuscular haematoma (c). Because of a new fall, 4 months later, CT of the brain was repeated and demonstrated restored symmetry of the temporal muscles due to resorption of the haematoma (d). I-FP-CIT SPECT was repeated and showed resolution of the right temporal activity (e). Extrastriatal I-FP-CIT uptake has already been described in a brain tumour in the case of a monoaminesynthesizing neuroendocrine cell tumour [3]. This case is a unique report of extracerebral I-ioflupane uptake due to subacute post-traumatic injury.

Extrastriatal uptake on 123 I-ioflupane brain SPECT

DaTSCAN® is a solution of I-ioflupane (I-FP-CIT), a cocaine analogue with high binding affinity for presynaptic dopamine transporters (DaT), in particular in the striatal region of the brain, suitable for SPECT imaging. It is mainly indicated for detecting loss of functional dopaminergic neuron terminals in the striatum in patients with clinically uncertain parkinsonian syndromes in order to help differentiate essential tremor from parkinsonian syndromes [1, 2]. A 72-year-old woman, with a history of tremor and postural hypotension, was admitted to our hospital because of a fall with crush syndrome. I-FP-CIT SPECT was performed and demonstrated besides normal dopaminergic activity in the striatum (a) focal extracerebral tracer uptake in the right temporal region (b). Correlation of the Iioflupane scan with MRI of the brain localized the extracerebral I focus in the right temporal muscle corresponding to an intramuscular haematoma (c). Because of a new fall, 4 months later, CT of the brain was repeated and demonstrated restored symmetry of the temporal muscles due to resorption of the haematoma (d). I-FP-CIT SPECT was repeated and showed resolution of the right temporal activity (e). Extrastriatal I-FP-CIT uptake has already been described in a brain tumour in the case of a monoaminesynthesizing neuroendocrine cell tumour [3]. This case is a unique report of extracerebral I-ioflupane uptake due to subacute post-traumatic injury.

Extrastriatal uptake on 123I-ioflupane brain SPECT

DaTSCAN® is a solution of I-ioflupane (I-FP-CIT), a cocaine analogue with high binding affinity for presynaptic dopamine transporters (DaT), in particular in the striatal region of the brain, suitable for SPECT imaging. It is mainly indicated for detecting loss of functional dopaminergic neuron terminals in the striatum in patients with clinically uncertain parkinsonian syndromes in order to help differentiate essential tremor from parkinsonian syndromes [1, 2]. A 72-year-old woman, with a history of tremor and postural hypotension, was admitted to our hospital because of a fall with crush syndrome. I-FP-CIT SPECT was performed and demonstrated besides normal dopaminergic activity in the striatum (a) focal extracerebral tracer uptake in the right temporal region (b). Correlation of the Iioflupane scan with MRI of the brain localized the extracerebral I focus in the right temporal muscle corresponding to an intramuscular haematoma (c). Because of a new fall, 4 months later, CT of the brain was repeated and demonstrated restored symmetry of the temporal muscles due to resorption of the haematoma (d). I-FP-CIT SPECT was repeated and showed resolution of the right temporal activity (e). Extrastriatal I-FP-CIT uptake has already been described in a brain tumour in the case of a monoaminesynthesizing neuroendocrine cell tumour [3]. This case is a unique report of extracerebral I-ioflupane uptake due to subacute post-traumatic injury.

Tracheobronchomalacia incidentally detected on Tc-99m ventilation/perfusion SPECT.

A Tc-99m Technegas MAA-SPECT was performed on an 81-year-old woman to exclude pulmonary embolism. It showed hypoperfusion and practically absent ventilation of the entire left lung, suggesting a left-sided centrally localized airway obstruction or compression with secondary hypoxic vasoconstriction. Subsequent bronchoscopy and CT scan detected tracheobronchomalacia with significant narrowing of the left bronchus.Tracheobronchomalacia is a rare, benign condition, referring to the deficiency in cartilage of the tracheobronchial tree, caused by a variety of factors.