Assessment of Apparent Diffusion Coefficients and SUVs as Predicators of Histological Differentiation in Anal Squamous Cell Carcinoma.

AIM: The study aims to assess minimal apparent diffusion coefficient (ADCmin) and SUVmax as predictors of histological differentiation in patients with anal squamous cell carcinoma (ASCC) and to determine cutoff values for each histopathological tumor grade. PATIENTS AND METHODS: A retrospective study of 41 ASCC patients (14 males, 27 females; mean age, 65 ± 13 years) staged with FDG PET/CT and MRI (mean scan time interval, 21 ± 11 days). SUVmax and ADCmin values were measured and compared with histopathological tumor grading obtained from biopsy. RESULTS: The mean size and tumor volume were 3 ± 2 cm and 16.5 ± 27.3 cm3, respectively. The mean ADCmin values for well-, moderately, and poorly differentiated ASCC were 935 ± 179, 896 ± 123, and 637 ± 114, respectively. The mean SUVmax for well-, moderately, and poorly differentiated ASCC were 6.9 ± 1.8, 11.5 ± 4.1, and 13.4 ± 2.6, respectively. The difference in mean ADCmin values between poorly and moderately/well-differentiated tumors was statistically significant, whereas this was not significant between moderately and well-differentiated tumors. Differences in SUVmax values were statistically significant between poorly/moderately and well-differentiated tumors, whereas there was no statistical significance between poorly and moderately differentiated tumors. By combining the 2 modalities using cutoff values of 675 × 10-6 mm2·s-1 for ADCmin and 8.5 for SUVmax, it was possible to differentiate the tumor categories with a sensitivity, specificity, positive predictive value, and negative predictive value, respectively, of 84.6%, 96.4%, 91.7%, and 93.1% for well-differentiated ASCC, 76.5%, 87.5%, 81.3%, and 84% for moderately, and 90.9%, 89.3%, 76.9%, and 96.2% for poorly differentiated ASCC, respectively. CONCLUSIONS: ADCmin and SUVmax values correlated with the degree of differentiation in ASCC and can be used as predictors of tumor grading and aggressiveness. Combined ADCmin and SUVmax cutoff values can therefore be used for early patient risk stratification and treatment decision making.

Improving liver lesion characterisation using retrospective fusion of FDG PET/CT and MRI.

AIM: To compare retrospectively fused FDG PET/CT and MRI (PET/MRI) to FDG PET/CT and MRI for characterisation of indeterminate focal liver lesions as malignant or benign in patients with a known primary malignancy. MATERIALS AND METHOD: A retrospective review of 70 patients (30 females, 40 males; mean age 56 ±â€¯14 years) with 150 indeterminate lesions after FDG PET/CT and MRI (mean scan time interval 21 ±â€¯11 days). HERMES® software was used to fuse PET/CT and MRI scans which were reviewed by 2 readers using the Likert score (scale 1-5) to characterise lesions as benign (1-3) or malignant (4-5). Final diagnosis was determined by histopathology or follow up imaging. Results for fused PET/MRI were compared to PET/CT and MRI alone. RESULTS: For detection, MRI and fused PET/MRI detected all the lesions while PET/CT detected 89.4%. Characterisation of liver lesions as malignant on PET/CT alone yielded sensitivity, specificity, accuracy, PPV and NPV of 55.6%, 83.3%, 66.7%, 83.3%, 55.6% respectively and 67.6%, 92.1%, 80%, 89.3%, 74.5% for MRI, respectively. The sensitivity, specificity, accuracy, PPV and NPV for characterising lesions as malignant increased to 91.9%, 97.4%, 94.7%, 97.1%, 92.5% with PET/MRI fusion. The sensitivity, specificity, accuracy, PPV and NPV of fused PET/MRI for characterising lesions as malignant remained superior to PET/CT and MRI. CONCLUSION: Retrospective fusion of PET with MRI has improved characterisation of indeterminate focal liver lesions compared to MRI or FDG PET/CT alone.

Incremental Value of SPECT/CT in the Detection of Femoral Head Viability in Slipped Capital Femoral Epiphysis.

In this article, we discuss the role of 99mTc-methylene diphosphonate SPECT/CT in 2 cases of slipped capital femoral epiphysis. We describe the incremental value of SPECT/CT in determining the viability of the femoral head and the implications in management of patients with slipped epiphysis.

Phenotypic appearances of prostate utilizing PET-MRI and PET-CT with 68Ga-PSMA, radiolabelled choline and 68Ga-DOTATATE.

The objective of this study was to highlight the role of multimodality imaging and present the differential diagnosis of abnormal tracer accumulation in the prostate and periprostatic tissue. Our departments have performed molecular imaging of the prostate utilizing PET-CT and PET-MRI with a range of biomarkers including F-FDG, radiolabelled choline, Ga-DOTATATE PET-CT and Ga-PSMA images. We retrospectively reviewed the varying appearances of the prostate gland in different diseases and incidental findings in periprostatic region. The differential diagnosis of pathologies related to prostate and periprostatic tissue on multimodality imaging includes malakoplakia, rhabdomyosarcoma, lymphoma, prostate cancer, neuroendocrine tumours, uchida changes, rectoprostatic fistula, synchronous malignancies, lymphocoele and schwanoma. There exists a wide differential for abnormal tracer accumulation in the prostate gland. As a radiologist and nuclear medicine physician, it is important to be aware of range of prostatic and periprostatic pathologies.

Localization of parathyroid disease with 'sequential multiphase and dual-tracer' technique and comparison with neck ultrasound.

OBJECTIVE: The aim of the study was to evaluate the accuracy of the sequential multiphase and dual-tracer (SMADT) technique utilizing technetium-99m pertechnetate (99mTcO4) and dynamic technetium-99m-2-methoxyisobutylisonitrile (99mTc-MIBI) with single-photon emission computed tomography/computed tomography (SPECT/CT) for localization of hyperfunctioning parathyroid tissue and compare the results with ultrasound (US). MATERIALS AND METHODS: Sixty-four patients with hyperparathyroidism were scanned over 4 years. For the SMADT technique, 80 MBq 99mTcO4 was injected with dynamic thyroid image acquisition started at 20 min, followed by 900 MBq 99mTc-MIBI injection at 30 min; the dynamic imaging continued for 50 min. SPECT was acquired at 60 min, with SPECT/CT of the neck at 3 h. Subsequent subtraction and statistical difference analyses were performed. Neck US was carried out within 3 months. Findings for each parathyroid gland and thyroid were classified as positive or negative. The patients underwent surgical resection of parathyroid tissue on the basis of imaging results. SMADT and US findings were correlated with histology as the gold standard. RESULTS: Eighty-six histological samples were resected. The sensitivity of SMADT for localization to individual glands was 70.6% [95% confidence interval (CI)=58.1-80.7%] and that for neck US was 60.3% (95% CI=47.7-71.8%, P=0.26). Specificity was 94.4% (95% CI=70.6-99.7%) for SMADT and 72.2% (95% CI=46.4-89.2%) for neck US (P=0.13). Sensitivities in multigland disease were 63.6% (95% CI=31.6-87.6%) for SMADT and 36.4% (95% CI=12.4-68.4%) for US (P=0.37) and in nodular thyroid disease were 83.8% (95% CI=67.3-93.2%) and 66.7% (95% CI=48.9-80.9%), respectively (P=0.07). CONCLUSION: SMADT results in better localization of varying parathyroid pathologies and complements the role of US in patients with multigland disease and nodular thyroid.

Prospective study of sentinel lymph node biopsy for conjunctival melanoma.

BACKGROUND: To report our experience with sentinel lymph node biopsy for staging patients with conjunctival melanoma. METHODS: A prospective review of patients with conjunctival melanoma who underwent sentinel lymph node biopsy at St Bartholomew's Hospital from May 2008 to May 2012. The selection criterion for sentinel node biopsy depended on the tumour thickness (≥2 mm) and location of the conjunctival melanoma. The main outcome measures were the incidence of sentinel lymph node positivity and the procedure-related complications. RESULTS: In 4 years, 26 out of 70 patients met the selection criteria for sentinel lymph node biopsy. 4 patients declined and 22 patients consented for the procedure. Technetium-99m failed to identify a sentinel lymph node in four of the 22 patients (18%). Of the remaining 18 patients, two were found to have subclinical micrometastasis in regional lymph nodes. Median follow-up was 20 months (range 6-36 months). No false-negative events were observed. Complications of the procedure included transient blue staining of the epibulbar surface in five patients and transient facial nerve palsy in one patient. CONCLUSIONS: Sentinel lymph node biopsy is a safe procedure with minimal complications. It should be considered for the staging of conjunctival melanomas, especially melanomas in non-limbal location or conjunctival melanomas ≥2 mm thick.

Frequency of left atrial and appendage clot in patients with severe mitral stenosis.

BACKGROUND: Left atrial thrombus is common in patients with mitral stenosis and atrial fibrillation; but how frequent it is in our population? The objective of study was to see the frequency of left atrial and appendage clot on trans-oesophageal echocardiography in symptomatic patients with severe mitral stenosis planned for PTMC. METHODS: Trans-oesophageal echocardiographic data retrieved from computer database Cardiology department, Lady Reading Hospital, Peshawar from August 1998 to Mach 2008. Patients admitted for PTMC under went trans-oesophageal echocardiography for detection of left atrial and appendage clot and quantification of mitral regurgitation. Data was analyzed on SPSS. RESULTS: Out of 1544 patients, males were 608 (39.4%), females were 936 (60.6%). Mean age was 30.84 +/- 12.6. Mean age of males was 30.56 +/- 13.1 years and females were 31.02 +/- 12.6 years. Minimum age was 8 years and maximum was 76 years. The mean LA size was 43.82 +/- 2.12 mm.Atrial fibrillation was observed in 289 (18.7%).Overall clot was seen in 224 (14.5%) patients. Left atrial appendage clot seen in 202 (89.73%).LA clot seen in 9 (4.02%). LAA/LA clot seen in 14 (6.25%). No significant difference was observed for clot among the gender distribution (p=0.42). Significant correlation was observed for clot in patients with AF and LA size > or = 45 mm, (p>0.001). CONCLUSION: The frequency of left atrial and appendage clots on trans-oesophageal echocardiography in patients with severe mitral stenosis is common and more frequent in patients with AF and LA size > or = 45 mm.