Accuracy of multidetector-row CT for restaging after neoadjuvant treatment in patients with oesophageal cancer

Objectives

To assess the diagnostic accuracy of 64-multidetector CT (MDCT) for restaging of patients with oesophageal cancer undergoing neoadjuvant therapy.

Methods

Results of pathological staging were correlated with those from 64-MDCT before and after neoadjuvant treatment in 35 patients using the American Joint Committee on Cancer/TNM classification (7th edition). CT response was determined using the Response Evaluation Criteria in Solid Tumours (RECIST) method, modified for one-dimensional tumour diameter measurement.

Results

64-MDCT predicted T stage correctly in 34 % (12/35), overstaged in 49 % (17/35) and understaged in 17 % (6/35). Sensitivity/specificity values were as follows: T0, 20 %/92 %; T1–T2, 31 %/59 %; T3, 60 %/64 %; T4, 100 %/4 %. Negative predictive values for T3/T4 were 80 %/100 %. MDCT accurately predicted complete histopathological response in 20 % (accuracy 74 %) and overstaged in 80 %. Tumour regression grade was predicted correctly in only 8 % (2/25) and underestimated in 68 % (17/25). Accurate N stage was noted in 69 % (24/35).

Conclusion

Although MDCT tends to be able to exclude advanced tumour stages (T3, T4) with a higher likelihood, the diagnostic accuracy of high resolution MDCT for restaging oesophageal cancer and assessing the response to neoadjuvant therapy has not improved in comparison to older-generation CT. Therefore, the future assessment of oesophageal tumour response should focus on combined morphologic and metabolic imaging.

Key Points

? Multidetector CT (MDCT) has been beneficial for the evaluation of many tumours. ? However diagnostic accuracy for restaging oesophageal cancer has not improved with MDCT. ? MDCT tends to be able to exclude advanced tumour stages (T3/T4). ? MDCT has a low accuracy for determining lymph node metastasis. ? Oesophageal tumour response should be assessed by combined morphological and metabolic imaging.     

Role of PET/CT in the detection of liver metastases from colorectal cancer

Purpose

The aim of this study was to compare the diagnostic accuracy of 2-[fluorine-18] fluoro-2-deoxy-D-glucose positron emission tomography (¹⁸F-FDG-PET) and computed tomography (CT) with PET/CT in the detection of liver metastases during tumour staging in patients suffering from colorectal carcinoma for the purposes of correct surgical planning and follow-up.

Materials and methods

A total of 467 patients underwent a PET/CT scan using an iodinated contrast medium. We compared images obtained by the single PET scan, the single CT scan and by the fusion of the two procedures (PET/CT). The final diagnosis was obtained by histological examination and/or by the follow-up of all patients, including those who did not undergo surgery or biopsy.

Results

The PET scan had 94.05% sensitivity, 91.60% specificity and 93.36% accuracy; the CT scan had 91.07% sensitivity, 95.42% specificity and 92.29% accuracy. The combined procedures (PET/CT) had the following values: sensitivity 97.92%, specificity 97.71% and accuracy 97.86%.

Conclusions

This study indicates that PET/CT is very useful in staging and restaging patients suffering from colorectal cancer. It was particularly useful when recurrences could not be visualised either clinically or by imaging despite increasing tumour markers, as it guaranteed an earlier diagnosis. PET/CT not only provides high diagnostic performance in terms of sensitivity and specificity, enabling modification of patient treatment, but it is also a unique, high-profile procedure that can produce cost savings.     

Utility of quantitative FDG-PET/CT for the detection of bone marrow involvement in follicular lymphoma: a histopathological correlation study

Objective

To determine the value of visual and quantitative ¹⁸?F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (FDG-PET/CT) for the detection of bone marrow involvement in follicular lymphoma, using direct histopathological examination at the right posterior iliac crest as reference standard.

Materials and methods

This retrospective study included 22 patients with newly diagnosed follicular lymphoma who had undergone FDG-PET/CT before BMB of the right posterior iliac crest. FDG-PET/CT images were visually evaluated for bone marrow involvement in the right posterior iliac crest. Volumes of interest were placed in the right posterior iliac crest to calculate the 3D partial volume corrected mean standardized uptake value (cSUV_mean), maximum standardized uptake value (SUV_max) and peak standardized uptake value (SUV_peak).

Results

Sensitivity and specificity of visual FDG-PET/CT analysis for the detection of bone marrow involvement in the right posterior iliac crest were 0.0 % (95 % confidence interval (CI): 0–32.4 %) and 100 % (95 % CI: 78.5–100 %), respectively. Areas under the receiver-operating characteristic curve of cSUV_mean, SUV_max and SUV_peak for the detection of bone marrow involvement in the right posterior iliac crest were 0.85 (95 % CI: 0.63–0.96), 0.89 (95 % CI: 0.68–0.98) and 0.87 (95 % CI: 0.65–0.97), respectively. Optimal cutoff values for cSUV_mean, SUV_max and SUV_peak were 1.3, 2.1 and 1.7, and yielded sensitivity and specificity combinations of 75.0 % and 85.7 %, 87.5 % and 85.7 % and 87.5 % and 85.7 %, respectively.

Conclusion

This histopathological correlation study shows that, unlike visual interpretation of FDG-PET/CT images, quantitative FDG-PET/CT analysis may be beneficial in diagnosing bone marrow involvement by follicular lymphoma.     

The diagnostic value of <Superscript>18</Superscript>F–FDG-PET/CT and MRI in suspected vertebral osteomyelitis – a prospective study

Purpose

The aim of this study was to determine the diagnostic value of ¹⁸F–fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) and magnetic resonance imaging (MRI) in diagnosing vertebral osteomyelitis.

Methods

From November 2015 until December 2016, 32 patients with suspected vertebral osteomyelitis were prospectively included. All patients underwent both ¹⁸F–FDG-PET/CT and MRI within 48 h. All images were independently reevaluated by two radiologists and two nuclear medicine physicians who were blinded to each others’ image interpretation. ¹⁸F–FDG-PET/CT and MRI were compared to the clinical diagnosis according to international guidelines.

Results

For ¹⁸F–FDG-PET/CT, sensitivity, specificity, PPV, and NPV in diagnosing vertebral osteomyelitis were 100%, 83.3%, 90.9%, and 100%, respectively. For MRI, sensitivity, specificity, PPV, and NPV were 100%, 91.7%, 95.2%, and 100%, respectively. MRI detected more epidural/spinal abscesses. An important advantage of ¹⁸F–FDG-PET/CT is the detection of metastatic infection (16 patients, 50.0%).

Conclusion

¹⁸F–FDG-PET/CT and MRI are both necessary techniques in diagnosing vertebral osteomyelitis. An important advantage of ¹⁸F–FDG-PET/CT is the visualization of metastatic infection, especially in patients with bacteremia. MRI is more sensitive in detection of small epidural abscesses.

     

Whole-body MRI with diffusion-weighted sequence for staging of patients with suspected ovarian cancer: a clinical feasibility study in comparison to CT and FDG-PET/CT

Objectives

To evaluate whole-body MRI with diffusion-weighted sequence (WB-DWI/MRI) for staging and assessing operability compared with CT and FDG-PET/CT in patients with suspected ovarian cancer.

Methods

Thirty-two patients underwent 3-T WB-DWI/MRI, ¹⁸?F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and CT before diagnostic open laparoscopy (DOL). Imaging findings for tumour characterisation, peritoneal and retroperitoneal staging were correlated with histopathology after DOL and/or open surgery. For distant metastases, FDG-PET/CT or image-guided biopsies were the reference standards. For tumour characterisation and peritoneal staging, WB-DWI/MRI was compared with CT and FDG-PET/CT. Interobserver agreement for WB-DWI/MRI was determined.

Results

WB-DWI/MRI showed 94 % accuracy for primary tumour characterisation compared with 88 % for CT and 94 % for FDG-PET/CT. WB-DWI/MRI showed higher accuracy of 91 % for peritoneal staging compared with CT (75 %) and FDG-PET/CT (71 %). WB-DWI/MRI and FDG-PET/CT showed higher accuracy of 87 % for detecting retroperitoneal lymphadenopathies compared with CT (71 %). WB-DWI/MRI showed excellent correlation with FDG-PET/CT (κ?=?1.00) for detecting distant metastases compared with CT (κ?=?0.34). Interobserver agreement was moderate to almost perfect (κ?=?0.58–0.91).

Conclusions

WB-DWI/MRI shows high accuracy for characterising primary tumours, peritoneal and distant staging compared with CT and FDG-PET/CT and may be valuable for assessing operability in ovarian cancer patients.

Key Points

? Whole-body MRI with diffusion weighting (WB-DWI/MRI) helps to assess the operability of suspected ovarian cancer. ? Interobserver agreement is good for primary tumour characterisation, peritoneal and distant staging. ? WB-DWI/MRI improves mesenteric/serosal metastatic spread assessment compared with CT and FDG-PET/CT. ? Retroperitoneal/cervical-thoracic nodal staging using qualitative DWI criteria was reasonably accurate. ? WB-DWI/MRI and FDG-PET/CT showed the highest diagnostic impact for detecting thoracic metastases.     

Detection of neck recurrence in patients with differentiated thyroid cancer: comparison of ultrasound, contrast-enhanced CT and 18F-FDG PET/CT using surgical pathology as a reference standard: (ultrasound vs. CT vs. 18F-FDG PET/CT in recurrent thyroid cancer)

Objectives

To compare the diagnostic performance of ultrasound, contrast-enhanced computed tomography (CT) and ¹⁸F-FDG positron emission tomography (PET)/CT for detecting recurrent differentiated thyroid cancer in the neck.

Methods

Twenty patients who had undergone previous surgery for differentiated thyroid cancer (19 papillary carcinomas; 1 medullary carcinoma) and presented with pathologically proven recurrence in the neck were included. All patients had undergone ultrasound, CT and PET/CT in the 2 months before further surgery. In each patient, ultrasound, CT and PET/CT images were retrospectively reviewed to determine the presence of loco-regional recurrence by level-by-level analysis. Imaging results were correlated with the histological evaluation of the neck dissection as a standard of reference.

Results

Recurrences were found at 52 out of 110 cervical nodal levels surgically explored. The sensitivity, specificity and accuracy were 69.2 %, 89.7 % and 80.0 % for ultrasound; 63.5 %, 94.8 % and 80.0 % for CT; and 53.8 %, 79.3 % and 67.3 % for PET/CT, respectively. ROC analysis revealed higher diagnostic performance with ultrasound than with PET/CT for detecting recurrent tumour.

Conclusions

Although no significant difference was found among the three techniques, the sensitivity and specificity of ultrasound and CT were higher than those of PET/CT for the evaluation of cervical recurrence in patients with differentiated thyroid cancer.

Key Points

? Ultrasound, CT and ¹⁸ F-FDG PET/CT can all detect recurrent thyroid cancer. ? Ultrasound and CT have higher sensitivity and specificity. ? Ultrasound, CT and ¹⁸ F-FDG PET/CT frequently demonstrated discordant findings     

[18F]FDG-PET/CT in patients affected by retroperitoneal fibrosis: a bicentric experience

Purpose

The aim of our study was to assess the feasibility and usefulness of 2-[¹⁸F]-fluoro-2-deoxy-d-glucose positron emission tomography computed tomography ([¹⁸F]FDG-PET/CT) in patients affected by retroperitoneal fibrosis.

Materials and methods

We retrospectively evaluated 25 patients studied in two centers: 18 underwent [¹⁸F]FDG-PET/CT as initial evaluation, three during follow-up, three during steroid therapy, and one to re-evaluate the disease. Among the group who underwent initial evaluation, ten underwent a second [¹⁸F]FDG-PET/CT after steroid therapy.

Results

[¹⁸F]FDG-PET/CT was positive in 18 patients and negative in seven. Among the ten patients who underwent a second study after steroid therapy, six showed complete metabolic response, three partial response, and one no significant maximum standardized uptake value (SUV_max) reduction.

Conclusion

Our preliminary results show that [¹⁸F]FDG-PET/CT is feasible and suitable for evaluating retroperitoneal fibrosis and is useful in assessing therapy response. Larger studies are desirable to confirm these findings and to determine the appropriate position of [¹⁸F]FDG-PET/CT in the diagnostic flow chart for this disease.     

Accuracy and predictive features of FDG-PET/CT and CT for diagnosis of lymph node metastasis of T1 non-small-cell lung cancer manifesting as a subsolid nodule

Objectives

To retrospectively evaluate the diagnostic accuracy and predictive features of F-18 fluorodeoxyglucose positron emission tomography/ computed tomography (FDG-PET/CT) and CT in lymph node (LN) staging of T1 non-small-cell lung cancers (NSCLCs) manifesting as subsolid nodules.

Methods

From January 2005 to May 2011, 160 patients with pathologically proven T1 subsolid NSCLCs with LN staging were included in this study. Diagnostic accuracies of FDG-PET/CT and CT for LN staging were evaluated. Maximum standardised uptake value (SUVmax) and CT features of primary tumours were evaluated to investigate predictive factors for LN metastasis.

Results

LN metastases were found in nine of the 160 patients (5.6%). No LN metastasis was present in patients with a solid proportion ≤50%. Sensitivity, specificity and accuracy of FDG-PET/CT for LN staging on a per-patient basis were 11.1%, 86.1% and 81.9%; those of CT were 11.1%, 96.7% and 91.9%. Among patients with a solid proportion >50%, there were significant differences in SUVmax, solid portion size, solid proportion and lesion location between patients with and without LN metastasis. Multivariate analysis revealed that higher SUVmax, a larger solid proportion and central location were independent predictors of LN metastasis.

Conclusions

FDG-PET/CT adds little value to CT in the lymph node staging of T1 subsolid NSCLCs.

Key Points

? Lymph node (LN) metastases are important in non-small-cell lung cancer (NSCLC). ? Positron emission tomography (PET) helps to stage solid NSCLCs. ? FDG-PET/CT adds little to the LN staging of T1 subsolid NSCLCs. ? No LN metastasis in patients with a solid proportion ≤50%. ? LN metastasis is more common in solid and/or centrally sited tumours.     

Comparison of FDG-PET, MRI and CT for post radiofrequency ablation evaluation of hepatic tumors

Purpose

Treatment effect of radiofrequency ablation (RFA) is traditionally accomplished with MRI and/or CT. The aim of the study was to assess the role of FDG-PET in post RFA hepatic tumor evaluation, in comparison with MRI and CT.

Materials and methods

28 patients (33 hepatic RFA lesions) who had post RFA FDG-PET within 8 weeks of abdominopelvic MRI or CT were retrospectively reviewed. Accuracy of FDG-PET on post hepatic RFA evaluation was compared with MRI and/or CT based on clinical and imaging follow-up.

Results

Among total of 33 RFA-treated lesions, 17 had residual or recurrent tumor (positive). PET identified 16 with a sensitivity of 94.1 %. Of these 17 lesions, 12 had concurrent MRI and 8 were positive with a sensitivity of 66.7 %. Similarly, 6 out of the 17 lesions had CT and 4 were positive with a sensitivity of 66.7 %. Sixteen lesions were successfully ablated (negative). Among them FDG-PET was negative in 13 with a specificity of 81.3 %; MRI was performed in 8 and 7 were negative with a specificity of 87.5 %; CT was performed in 8 and 5 were negative with a specificity of 62.5 %. The overall accuracy of PET, MRI and CT was 87.9, 75.0, and 64.3 %, respectively. The average scan numbers for PET, MRI and CT to achieve a final accurate diagnosis were 1.121, 1.316 and 1.250, with a corresponding cost of $1455.2, $1845.8, and $933.8, respectively.

Conclusions

The study suggests that FDG-PET is superior to MRI and/or CT and is more cost-effective in post RFA hepatic tumor assessment.     

Role of 68Ga-DOTATOC PET/CT in initial evaluation of patients with suspected bronchopulmonary carcinoid

Purpose

The objective of this study was to evaluate the role of ⁶⁸Ga-DOTATOC positron emission tomography (PET)/CT scan in patients with suspected pulmonary carcinoid tumour and to compare its results with ¹⁸F-fluorodeoxyglucose (FDG) PET/CT scan.

Methods

In this prospective study, 32 patients (age 34.22?±?12.03 years; 53.1 % female) with clinical suspicion of bronchopulmonary carcinoid were evaluated with ⁶⁸Ga-DOTATOC PET/CT and ¹⁸F-FDG PET/CT. The two imaging modalities were compared, considering the tissue diagnosis as the reference standard.

Results

Based on the reference standard 26 cases were carcinoid tumours [21 typical carcinoids (TC) and 5 atypical carcinoids (AC)] and 6 cases were non-carcinoid tumours. The sensitivity, specificity and accuracy of ⁶⁸Ga-DOTATOC PET/CT in the diagnosis of pulmonary carcinoid tumour were 96.15, 100 and 96.87 % respectively, whereas those of ¹⁸F-FDG PET/CT were 78.26, 11.1 and 59.37 % respectively. The maximum standardised uptake value (SUV_max) of TC on ⁶⁸Ga-DOTATOC PET/CT scan ranged from 3.58 to 55, while that of AC ranged from 1.1 to 32.5. ¹⁸F-FDG PET/CT was true-positive in all cases of AC and false-negative in eight cases of TC (sensitivity for TC 61.9 % and for AC 100 %).

Conclusion

⁶⁸Ga-DOTATOC PET/CT is a useful imaging investigation for the evaluation of pulmonary carcinoids. ¹⁸F-FDG PET/CT scan suffers from low sensitivity and specificity in differentiating the pulmonary carcinoids from other tumours.     

F-18 FDG-PET/CT in evaluation of patients with fever of unknown origin

Objectives

This study was carried out to evaluate the diagnostic utility of FDG-PET/CT in patients with fever of unknown origin (FUO).

Methods

Medical records of 103 patients who underwent FDG-PET/CT and anatomic imaging as a part of FUO workup were analyzed. Final diagnosis of the cause of FUO was reached based on serologic assays, cultures, biopsy, surgery or 6 months of clinical follow-up.

Results

The definite cause of fever was established in 69/103 patients. Abnormal FDG uptake was found in 63/103 patients and contributed to the final diagnosis (TP) in 62 patients (98.48 %). Of the remaining 40 patients with negative PET/CT, the final definite cause of fever (FN) could be determined only in seven patients (17.5 %). PET/CT had a sensitivity, specificity, positive predictive value and negative predictive value of 90, 97, 98.4 and 82.5 % compared to 43.5, 67.6, 73.2 and 37.1 %, respectively, for anatomic imaging. FDG-PET/CT had a higher accuracy (92.2 vs. 51.5 %; p = 0.003) compared to anatomic imaging for suggesting a cause of FUO.

Conclusions

PET/CT showed high sensitivity and specificity in suggesting a definite diagnosis in the evaluation of FUO.     

Clinical significance of 18F-α-methyl tyrosine PET/CT for the detection of bone marrow invasion in patients with oral squamous cell carcinoma: comparison with 18F-FDG PET/CT and MRI

Objective

L-3-[¹⁸F]-fluoro-α-methyl tyrosine (¹⁸F-FAMT) is an amino acid tracer for positron emission tomography/computed tomography (PET/CT) which specifically transported into cancer cells by L-type amino acid transporter 1 (LAT1). LAT1 overexpression in tumors is significantly correlated with cell proliferation and angiogenesis. ¹⁸F-FAMT PET/CT, fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) PET/CT and magnetic resonance imaging (MRI) were compared for their diagnostic performance in the detection of bone marrow invasion in patients with oral squamous cell carcinoma (OSCC).

Methods

Twenty-seven patients with OSCC on the upper or lower alveolar ridge underwent staging by MRI, ¹⁸F-FDG PET/CT and ¹⁸F-FAMT PET/CT studies before surgery. Post-surgical pathologic examination was used as the standard to determine the final diagnoses. The possibility of bone marrow invasion on MRI, ¹⁸F-FDG PET/CT and ¹⁸F-FAMT PET/CT were usually graded retrospectively into five-point score. Sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated according to the obtained scores.

Results

As the sensitivity of ¹⁸F-FDG PET/CT was highest (100 %) among that of MRI (95 %) and ¹⁸F-FAMT PET/CT (90 %), the specificity of ¹⁸F-FAMT PET/CT was highest (85.7 %) among that of MRI (57 %) and ¹⁸F-FDG PET/CT (14.3 %). The size of pathological tumor was accorded with that detected by ¹⁸F-FAMT PET/CT and was smaller than that detected by ¹⁸F-FDG PET/CT (P < 0.01). Significant difference was not found between ¹⁸F-FAMT PET tumor volume and pathological tumor volume.

Conclusions

¹⁸F-FAMT PET/CT was useful and more specific than MRI or ¹⁸F-FDG PET/CT in the detection of bone marrow invasion of OSCC and may contribute to minimize the extent of resection in oral surgery patient.     

Role of 11C-choline positron emission tomography/computed tomography in evaluating patients affected by prostate cancer with suspected relapse due to prostate-specific antigen elevation

Purpose

The aim of this study was to evaluate the accuracy of ¹¹C-choline positron emission tomography/computed tomography (PET/CT) in restaging patients affected by prostate cancer and suspected relapse due to prostate-specific antigen (PSA) increase. We also aimed to determine a PSA cutoff that is most suited to the study in terms of best compromise between sensitivity and specificity. Secondary endpoints were a comparison between ¹¹C-choline PET/CT and histological results, clinical findings, and radiological imaging (CT and magnetic resonance imaging).

Materials and methods

We retrospectively evaluated 210 patients (median ± SD age 70 ± 7 years) affected by prostate cancer who underwent ¹¹C-choline PET/CT.

Results

¹¹C-choline PET/CT imaging was positive in 116 (55.2%) patients and negative in 94 (44.8%). Receiver operating characteristic (ROC) analysis showed that the highest accuracy (sensitivity 76.8%, specificity 92.5%) for the whole population was achieved when the PSA level of 1.26 ng/ml level was used as the cutoff value for interpreting the results (P = 0.0001 and the area under the ROC curve AUC 0.897). For patients treated with surgery or surgery plus radiotherapy the cutoff was 0.81 ng/ml (sensitivity 73.2%, specificity 86.1%). For patients treated with radiotherapy alone, the cutoff was 2.0 ng/ml (sensitivity 81.8%, specificity 92.9%).

Conclusion

Our results indicate that ¹¹C-choline PET/CT is a useful diagnostic tool in patients affected by prostate cancer and a relapsed PSA level. The highest accuracy for all patients is obtained with a PSA cutoff level of 1.26 ng/ml, above which the imaging study is performed (0.81 ng/ml for patients treated with surgery or surgery plus radiotherapy and 2.0 ng/ml for patients treated with radiotherapy alone).     

Diagnostic accuracy of segmental enhancement inversion for diagnosis of renal oncocytoma at biphasic contrast enhanced CT: systematic review

Objectives

To use systematic review to evaluate the diagnostic accuracy of segmental enhancement inversion (SEI) at contrast-enhanced biphasic multi-detector computed tomography (MDCT) for the diagnosis of renal oncocytoma.

Methods

Several electronic databases were searched through October 2013. Two reviewers independently selected studies that met the inclusion criteria and extracted data. Study quality was assessed with the QUADAS-2 tool. The primary 2?×?2 data were investigated with forest plot and ROC plot of sensitivity and specificity.

Results

Four studies met the inclusion criteria (307 patients). Considerable heterogeneity between studies precluded meta-analysis. Two studies from the same group of investigators demonstrated reasonable diagnostic accuracy (sensitivity 59-80 % and specificity 87-99 %), while two others did not (sensitivity 0-6 %, specificity 93-100 %). Possible reasons for this include timing of biphasic MDCT and methods of interpretation but not size of lesion.

Conclusions

SEI is a specific imaging finding of renal oncocytoma with highly variable sensitivity. This substantial heterogeneity across studies and between institutions suggests that further validation of this imaging finding is necessary prior to application in clinical practice.

Key Points

? SEI on CT in small renal masses is specific for oncocytoma. ? Sensitivity of SEI varies substantially between studies and across institutions. ? Variability could relate to CT timing or methods of interpretation. ? High accuracy of SEI has only been reported by one group. ? Validation of SEI is needed prior to clinical implementation.     

Clinical value of a high-fat and low-carbohydrate diet before FDG-PET/CT for evaluation of patients with suspected cardiac sarcoidosis

Background

We hypothesized that a high-fat and low-carbohydrate (HFLC) diet before FDG-PET/CT could identify patients with active cardiac sarcoidosis (CS).

Methods

Fifty-eight sarcoidosis patients with a suspicion of CS consumed a HFLC diet before FDG-PET/CT. Clinical, electrical, and other imaging investigations were compared to PET results.

Results

Using Japanese Ministry of Health and Welfare (JMHW) criteria as a gold standard, 21% (12/58) of patients had a CS. Sensitivity and specificity of PET (visual analysis) were 83% (10/12) and 78% (36/46), respectively, with a very good interobserver agreement (k = 0.86). 70% (7/10) of the patients with a positive PET and negative JMHW criteria exhibited abnormalities suggestive of CS either on MR (n = 3) or SPECT (n = 4). Comparison with the presence of delayed enhancement on magnetic resonance imaging helped to classify patients with active (PET positive) or non-active CS (PET negative). In addition, when MR and PET were both negative, none of the patients met the JMHW criteria. PET response under treatment was concordant with clinical evolution in 11/13 patients.

Conclusions

FDG-PET/CT after HFLC diet is a sensitive tool for the diagnosis of active CS. Combined use of PET and MR is promising for the detection and characterization of CS lesions.     

Performance profile of a FDG-PET cancer screening program for detecting gastric cancer: results from a nationwide Japanese survey

Purpose

It has been reported that gastric cancer is the sixth most common cancer found during the ¹⁸F-fluorodeoxyglucose-positron emission tomography (FDG-PET) cancer screening program, which is defined as cancer screening of asymptomatic subjects using FDG-PET(/CT) (in combination with other screening tests or not). The aim of this study was to analyze the detection rate and the effectiveness of the FDG-PET cancer screening program at detecting gastric cancer between 2006 and 2009 in Japan.

Materials and methods

A total of 153,775 asymptomatic subjects (92,255 men, 61,520 women) between 30 and 80 years old underwent the FDG-PET cancer screening program. Of these, we analyzed 790 cases with findings of possible gastric cancer in any screening test.

Results

The number of cases who were verified to have gastric cancer was 124. Among these, only 47 cases were detected by FDG-PET, which resulted in a relative sensitivity of 37.9 % and a positive predictive value of 33.6 %. The relative sensitivity of FDG-PET was much lower than those of gastric endoscopy and the serum pepsinogen test.

Conclusion

The FDG-PET screening program in Japan detected some cases of early-stage gastric cancer, but this was not achieved using FDG-PET alone but in combination with gastric endoscopy. Gastric endoscopy should be included in FDG-PET cancer screening programs to screen for gastric cancer.     

Hepatocellular carcinoma in cirrhotic patients: prospective comparison of US, CT and MR imaging

Objectives

To prospectively compare the diagnostic performance of ultrasound (US), multidetector computed tomography (MDCT) and contrast-enhanced magnetic resonance imaging (MRI) in cirrhotic patients who were candidates for liver transplantation.

Methods

One hundred and forty consecutive patients with 163 hepatocellular carcinoma (HCC) nodules underwent US, MRI and MDCT. Diagnosis of HCC was based on pathological findings or substantial growth at 12-month follow-up. Four different image datasets were evaluated: US, MDCT, MRI unenhanced and dynamic phases, MRI unenhanced dynamic and hepatobiliary phase. Diagnostic accuracy, sensitivity, specificity, PPV and NPV, with corresponding 95 % confidence intervals, were determined. Statistical analysis was performed for all lesions and for three lesion subgroups (<1 cm, 1-2 cm, >2 cm).

Results

Significantly higher diagnostic accuracy, sensitivity and NPV was achieved on dynamic + hepatobiliary phase MRI compared with US, MDCT and dynamic phase MRI alone. The specificity and PPV of US was significantly lower than that of MDCT, dynamic phase MRI and dynamic + hepatobiliary phase MRI. Similar results were obtained for all sub-group analyses, with particular benefit for the diagnosis of smaller lesions between 1 and 2 cm.

Conclusions

Dynamic + hepatobiliary phase MRI improved detection and characterisation of HCC in cirrhotic patients. The greatest benefit is for diagnosing lesions between 1 and 2 cm.

Key Points

? US, CT and MRI can all identify HCC in cirrhotic patients ? US has good sensitivity but suffers from false-positive findings ? Dynamic CT and MR have similar diagnostic performance for diagnosing HCC ? Dynamic + hepatobiliary phase MRI significantly improves detection and characterisation of HCC ? The greatest benefit is for the diagnosis of lesions between 1 and 2 cm     

Clinical impact of whole body FDG-PET for recurrent biliary cancer: a multicenter study

Objective

To evaluate the clinical usefulness of positron emission tomography (PET) using ¹⁸F-fluorodeoxyglucose (FDG) in patients with follow-up or suspected recurrent biliary cancer in a multicenter study.

Methods

We performed a retrospective review of 50 patients who underwent FDG-PET (either integrated PET/CT or manual fusion of dedicated PET and CT) scans for post-treatment surveillance of biliary cancer. Recurrence was suspected in 40 of these patients on the basis of tumor marker levels, and/or findings of conventional imaging (group A). Clinical findings in the remaining 10 patients showed them to be disease-free (group B). The diagnostic performance and clinical impact of PET were analyzed.

Results

Recurrence was confirmed in 28 out of the 40 patients in group A, and 1 of the 10 patients in group B. Patient-based analysis showed that the sensitivity, specificity, and accuracy of PET for detecting recurrence were 86% (25/29), 91% (19/21), and 88% (44/50), respectively. The one patient with recurrence in group B was correctly interpreted by PET. Positive test likelihood ratio and negative test likelihood ratio were increased from 1.69 to 9.05, and 0.08 to 0.32, respectively, after PET study. The findings of PET resulted in a change of management for 10 out of the 50 patients (20%) by initiating an unplanned treatment strategy (n = 7), by obviating the need for planned diagnostic procedures (n = 2), or by changing the treatment plan (n = 1).

Conclusion

FDG-PET/CT or PET with CT yielded helpful information in patients with suspected recurrent biliary cancer.     

The value of 18F-FDG PET/CT in diagnosing infectious endocarditis

Purpose

Early detection of infectious endocarditis is challenging. For diagnosing infectious endocarditis, the revised Duke criteria are the gold standard. Evidence of endocardial involvement on echocardiography is a major criterion, but sensitivity and specificity of echocardiography are not optimal. Here we investigated the utility of ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography and computed tomography (PET/CT) to diagnose infectious endocarditis in patients with gram-positive bacteraemia.

Methods

Seventy-two patients with gram-positive bacteraemia were prospectively included. Patients with a positive blood culture growing Staphylococcus aureus, Streptococcus species or Enterococcus species were eligible when a risk factor for developing metastatic infectious foci was present. Infectious endocarditis was defined according to the revised Duke criteria. All patients underwent ¹⁸F-FDG PET/CT and echocardiography. ¹⁸F-FDG uptake in or around the heart valves was evaluated independently by two nuclear medicine physicians.

Results

Sensitivity for diagnosing infectious endocarditis with ¹⁸F-FDG PET/CT was 39 % and specificity was 93 %. The positive predictive value was 64 % and negative predictive value was 82 %. The mortality rate in patients without infectious endocarditis and without increased ¹⁸F-FDG uptake in or around the heart valves was 18 %, and in patients without infectious endocarditis but with high ¹⁸F-FDG uptake in or around the heart valves the mortality rate was 50 % (p?=?0.181).

Conclusion

¹⁸F-FDG PET/CT is currently not sufficiently adequate for the diagnosis of infectious endocarditis because of its low sensitivity. Improvements such as patient preparation with low carbohydrate–fat allowed diet and technical advances in the newest PET/CT scanners may increase sensitivity in future studies.     

Diagnostic usefulness of an amino acid tracer, α-[N-methyl-11C]-methylaminoisobutyric acid (11C-MeAIB), in the PET diagnosis of chest malignancies

Objectives

Although positron emission tomography (PET) using [¹⁸F]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) is established as one of the first-choice imaging modalities in the diagnosis of chest malignancies, there are several problems to solve in clinical practice, such as false positive uptake in inflammatory diseases. The aim of this study was to evaluate the clinical usefulness of an amino acid tracer, α-[N-methyl-¹¹C]-methylaminoisobutyric acid (¹¹C-MeAIB), in the diagnosis of chest malignancies, in combination with ¹⁸F-FDG.

Setting

Fifty-nine cases (57 patients, 66 ± 12 years old) who consulted to our institution for the wish to receive differential diagnosis of chest diseases were included. Purpose of the studies were as follows: differential diagnosis of newly developed lung nodules, n = 22; newly developed mediastinal lesions, n = 20; and both, n = 17 (including lung cancer: n = 19, lymphoma: n = 1, other cancers: n = 2, sarcoidosis: n = 15, non-specific inflammation: n = 18, other inflammatory: n = 4, respectively). Whole-body static PET or PET/CT scan was performed 20 and 50 min after the IV injection of ¹¹C-MeAIB and ¹⁸F-FDG, respectively.

Results

¹¹C-MeAIB uptake of malignant and benign lesions was statistically different both in pulmonary nodules (p < 0.005) and in mediastinal lesions (p < 0.0005). In visual differential diagnosis, ¹¹C-MeAIB showed higher results (specificity: 73 %, accuracy: 81 %), compared to those in ¹⁸F-FDG (60, 73 %, respectively). In cases of sarcoidosis, ¹¹C-MeAIB showed higher specificity (80 %) with lower uptake (1.8 ± 0.7) in contrast to the lower specificity (60 %) with higher uptake of ¹⁸F-FDG (7.3 ± 4.5).

Conclusions

¹¹C-MeAIB PET/CT was useful in the differential diagnosis of pulmonary and mediastinal mass lesions found on CT. ¹¹C-MeAIB PET or PET/CT showed higher specificity than that of ¹⁸F-FDG PET/CT in differentiating between benign and malignant disease. Our data suggest that the combination of ¹⁸F-FDG and ¹¹C-MeAIB may improve the evaluation of chest lesions, when CT and ¹⁸F-FDG PET/CT are equivocal.