Comparison of 68Ga-DOTANOC PET/CT and contrast-enhanced CT in localisation of tumours in ectopic ACTH syndrome

BACKGROUND

Localising ectopic adrenocorticotrophic hormone (ACTH) syndrome (EAS) tumour source is challenging. Somatostatin receptor-based PET imaging has shown promising results, but the data is limited to case reports and small case series. We reviewed here the performance of (68)Ga-DOTANOC positron emission tomography (PET)/computed tomography (CT) and contrast-enhanced CT (CECT) in our cohort of 12 consecutive EAS patients.

MATERIALS AND METHODS

Retrospective data analysis of 12 consecutive patients of EAS presenting to a single tertiary care centre in a period between January 2013 and December 2014 was done. CECT and (68)Ga-DOTANOC PET/CT were reported (blinded) by an experienced radiologist and a nuclear medicine physician, respectively. The performance of CECT and (68)Ga-DOTANOC PET/CT was compared.

RESULTS

Tumours could be localised in 11 out of 12 patients at initial presentation (overt cases), whereas in one patient, tumour remained occult. Thirteen lesions were identified in 11 patients as EAS source (true positives). CECT localised 12 out of these 13 lesions (sensitivity 92.3%) and identified five false-positive lesions (positive predictive value (PPV) 70.5%). Compared with false-positive lesions, true-positive lesions had greater mean contrast enhancement at 60s (33.2 vs 5.6 Hounsfield units (HU)). (68)Ga-DOTANOC PET/CT was able to identify 9 out of 13 lesions (sensitivity 69.2%) and reported no false-positive lesions (PPV 100%).

CONCLUSION

CECT remains the first-line investigation in localisation of EAS. The contrast enhancement pattern on CECT can further aid in characterisation of the lesions. (68)Ga-DOTANOC PET/CT can be added to CECT, to enhance positive prediction of the suggestive lesions.

EVALUATION OF MULTIPLEX LIGATION DEPENDENT PROBE AMPLIFICATION AS A TOOL FOR DIAGNOSIS AND CARRIER DETECTION IN FAMILIES WITH A DYSTROPHINOPATHY

We set out to evaluate multiplex ligation dependent probe amplification (MLPA) as a tool for diagnosis and carrier detection in families with a dystrophinopathy. Fifty three Indian families with provisional diagnosis of Duchene muscular dystrophy or Becker muscular dystrophy were evaluated by MLPA and multiplex polymerase chain reaction (PCR). Sanger sequencing was used to analyze the entire gene in one patient. Mothers were tested for carrier status whenever possible. Molecular analysis of DMD gene by combining MLPA and multiplex PCR yielded a mutation detection rate of 62% (33/53). Deletions were detected in 27/53 (51%) cases, duplications in 5/53 (9%) cases, a small deletion one case and Sanger sequencing detected a nonsense mutation in one case. Mutation was not detected in 36% (19/53) cases. Fifty six percent of mothers (9/16) were found to be carriers. MLPA helped to refine the results of multiplex PCR testing in 22 patients (5 duplications, 16 deletions and one small deletion). We also describe a situation where a deletion of single exon on MLPA (but not detected by multiplex PCR) was actually due to a deletion of two nucleotides in the probe ligation site. MLPA appears to score over multiplex PCR in diagnosis and carrier detection, specifically by detecting deletions and duplications that are not detected by traditional multiplex PCR.

Vitamin D as a marker of cognitive decline in elderly Indian population

Objectives:

Very few studies in India have addressed the role of vitamin D in cognitive function. The present study was conducted to assess the serum levels of 25-hydroxyvitamin D (25(OH)D) and its association with markers of cognitive impairment and homocysteine levels in the elderly Indian population.

Materials and Methods:

The study population consisted of patients with dementia (Group A, n = 32), mild cognitive impairment (MCI; Group B, n = 24), and elderly age-matched controls (Group C, n = 30). Measurement of serum levels of 25(OH)D and total homocysteine were done.

Results:

Significant decreased concentration of 25(OH)D and increased concentration of homocysteine was observed. Association of serum levels of vitamin D with markers of cognitive decline as well as serum homocysteine levels was observed in patients with dementia and MCI when compared to controls.

Conclusion:

Correlation of vitamin D with markers of cognitive decline and homocysteine opens a new door for early diagnosis of cognitive impairment.

ProLuCID: An improved SEQUEST-like algorithm with enhanced sensitivity and specificity

ProLuCID, a new algorithm for peptide identification using tandem mass spectrometry and protein sequence databases has been developed. This algorithm uses a three tier scoring scheme. First, a binomial probability is used as a preliminary scoring scheme to select candidate peptides. The binomial probability scores generated by ProLuCID minimize molecular weight bias and are independent of database size. A modified cross-correlation score is calculated for each candidate peptide identified by the binomial probability. This cross-correlation scoring function models the isotopic distributions of fragment ions of candidate peptides which ultimately results in higher sensitivity and specificity than that obtained with the SEQUEST XCorr. Finally, ProLuCID uses the distribution of XCorr values for all of the selected candidate peptides to compute a Z score for the peptide hit with the highest XCorr. The ProLuCID Z score combines the discriminative power of XCorr and DeltaCN, the standard parameters for assessing the quality of the peptide identification using SEQUEST, and displays significant improvement in specificity over ProLuCID XCorr alone. ProLuCID is also able to take advantage of high resolution MS/MS spectra leading to further improvements in specificity when compared to low resolution tandem MS data. A comparison of filtered data searched with SEQUEST and ProLuCID using the same false discovery rate as estimated by a target-decoy database strategy, shows that ProLuCID was able to identify as many as 25% more proteins than SEQUEST. ProLuCID is implemented in Java and can be easily installed on a single computer or a computer cluster. This article is part of a Special Issue entitled: Computational Proteomics.

Adolescent Volar Barton Fracture with Open Physis treated with Volar Plating using Buttressing Principle

Objective: The objective of the study was to assess the outcome of Salter- Harris type III distal radius fracture fixed using the principle of buttressing and avoiding screw insertion through the physis.

Materials and Method: Eight school going children in the age group of 11-16 years with volar Barton fractures were treated with a volar plate using the buttress principle without inserting screws in the distal fragment. Patients were evaluated over a period of 18 months. Clinical evaluation was done using the Green O’Brien criteria and radiological evaluation using the Sarmiento criteria.

Results: The average union time was two months. All the patients had good to excellent functional outcome with full extension and flexion.

Conclusion: Buttress plating of volar Barton fractures in the adolescent age group is an excellent technique to achieve satisfactory outcome without violation of the physis.

Patients’ motivations for treatment and their experiences of orthodontic preparation for orthognathic surgery

OBJECTIVE

To determine patients' motivations for undergoing orthognathic surgery and their experiences of the orthodontic aspects of this treatment.

DESIGN

Retrospective questionnaire survey using a patient-centred measure.

SETTING

Thirteen National Health Service (NHS) hospital orthodontic departments.

SUBJECTS

Three-hundred-and-twenty-six patients (58% response rate) who underwent orthognathic surgery during the period 1 January 1995 to 30 September 2001 completed a questionnaire.

MAIN OUTCOME MEASURES

Motivations for treatment and perception of information about treatment and experiences of orthodontic treatment.

RESULTS

Major motivations for treatment were to have straight teeth (80%), to prevent future dental problems (69%) and to improve self-confidence (68%). Females sought treatment to improve self-confidence and their smile. Males wanted treatment to improve their social life. Most of these issues had improved following surgery. Most (94%) respondents felt well-informed about their orthodontics. However, 36% wore braces for longer than they expected. Males and younger patients knew less about the duration of treatment than other groups. Fifty-eight per cent of subjects found their braces difficult to clean and 9% reported that they were very painful. Older patients experienced fewer problems wearing braces than younger patients.

CONCLUSIONS

Improving dental appearance and preventing future dental problems are major motivators for orthognathic patients. Although patients felt well informed about what to expect from their orthodontic treatment, a significant proportion, particularly younger patients and males, were surprised at the length of treatment and the need to wear retainers. This suggests that orthognathic patients might benefit from better information regarding the orthodontic aspects of their care.

An interesting case of primary hypoparathyroidism

Primary hypoparathyroidism can occur due to an activating mutation of calcium sensing receptor (CaSR). Most patients remain asymptomatic and therefore not diagnosed until adulthood. We present a 38-year-old lady who had a history of muscle cramps since 8 years. She presented with vomiting, abdomen pain and body ache, showed clinical evidence of hypovolemia, severe hypocalcemia, hypokalemia, hypomagnesemia, hyperphosphatemia and metabolic alkalosis. Her 24 h urinary phosphorus was low and 24 h urinary excretion of sodium, potassium and chloride were high. Her intact parathormone was on the lower side of the normal range. She improved once we had corrected her biochemical abnormalities. By excluding acquired causes of hypoparathyroidism, we are able to conclude that this may be a case of primary hypoparathyroidism due to activating mutation of CaSR.

Functional imaging in primary tumour-induced osteomalacia: relative performance of FDG PET/CT vs somatostatin receptor-based functional scans: a series of nine patients

CONTEXT

Localization of phosphatonin-producing mesenchymal tumours in patients with primary tumour-induced osteomalacia (pTIO) is challenging. Functional imaging plays an important role in the localization of these tumours.

OBJECTIVE

We studied the relative performance of different functional imaging modalities ((18) F-FDG PET/CT, (99) Tc-HYNIC-TOC SPECT/CT and (68) Ga-DOTATATE PET/CT) in tumour localization in cases of pTIO.

DESIGN AND METHODS

Retrospective chart evaluation of 16 patients with confirmed TIO treated from 2006 to 2013 was conducted in a tertiary care referral centre.

RESULTS

Of 16, nine patients had pTIO. In these nine, the positivity rates of different functional imaging modalities were 50% for (18) F-FDG PET/CT (four of eight patients), 100% for (99) Tc-HYNIC-TOC SPECT/CT (six of six patients) and 100% for (68) Ga-DOTATATE PET/CT (seven of seven patients). Of nine patients, six were subjected to both the (99) Tc-HYNIC-TOC SPECT/CT and (68) Ga-DOTATATE PET/CT and all of them showed coregistration on the two scans.

CONCLUSIONS

In patients with pTIO, the somatostatin receptor-based functional scans performed better than (18) F-FDG PET/CT in tumour localization. Amongst the somatostatin receptor-based scans, (99) Tc-HYNIC-TOC SPECT/CT and (68) Ga-DOTATATE PET/CT performed equally well for localization of tumours.

Familial hypercholesterolaemia IIA with bicuspid aortic valve

A young male presented with multiple xanthomas and xanthelesmas, progressive breathlessness and angina on exertion. Investigations confirmed diagnosis of familial hypercholesterolaemia, bicuspid aortic valve with severe aortic stenosis and significant obstructive coronary artery disease.