Ali Nawaz Khan

The calcified lung nodule: What does it mean?

The aim of this review is to present a pictorial essay emphasizing the various patterns of calcification in pulmonary nodules (PN) to aid diagnosis and to discuss the differential diagnosis and the pathogenesis where it is known. The imaging evaluation of PN is based on clinical history, size, distribution and the gross appearance of the nodule as well as feasibility of obtaining a tissue diagnosis. Imaging is instrumental in the management of PN and one should strive not only to identify small malignant tumors with high survival rates but to spare patients with benign PN from undergoing unnecessary surgery. The review emphasizes how to achieve these goals. One of the most reliable imaging features of a benign lesion is a benign pattern of calcification and periodic follow-up with computed tomography showing no growth for 2 years. Calcification in PN is generally considered as a pointer toward a possible benign disease. However, as we show here, calcification in PN as a criterion to determine benign nature is fallacious and can be misleading. The differential considerations of a calcified lesion include calcified granuloma, hamartoma, carcinoid, osteosarcoma, chondrosarcoma and lung metastases or a primary bronchogenic carcinoma among others. We describe and illustrate different patterns of calcification as seen in PN on imaging.

Renal medullary carcinoma: sonographic, computed tomography, magnetic resonance and angiographic findings.

Renal medullary carcinoma is a recently described, highly aggressive tumour, occurring predominantly in young patients of African descent with sickle cell trait (SCT). All have been metastatic at surgery. Surgery, radiotherapy and chemotherapy do not appear to alter the course of the disease. The survival time is very short. Presentation is usually with haematuria, abdominal pain and weight loss. Forty-nine patients have been reported from the USA, of these 47 were African/Americans. The reports have mostly appeared in pathology journals. On review of the imaging findings reported in the radiological journals, it becomes apparent that it is possible for a radiologist to suggest a specific diagnosis in the appropriate demographic and clinical setting. Here the first British patient of Afro-Caribbean decent in whom a pre-operative diagnosis was suggested on the imaging findings of a centrally located renal pelvic tumour, encasing the pelvis on a background of SCT in a 28-year-old is described. It is expected that a high index of suspicion in the appropriate clinical setting may lead to earlier diagnosis, treatment and survival of patients. The patient is alive and reasonably well 9 months after surgery. The full range of imaging findings in renal medullary carcinoma are described.

Perfusion of 99Tcm-labeled CD105 Mab into kidneys from patients with renal carcinoma suggests that CD105 is a promising vascular target

There is strong published and unpublished evidence that our CD105 Mab E9, which is highly reactive with angiogenic endothelial cells, could be a useful reagent to target the vasculature of solid tumors in man. Since Mab E9 does not cross‐react with animal tissues, we undertook here to evaluate its localization using human kidney as an ex vivo model. Perfusion was performed through the renal artery of 99Tcm‐labeled purified CD105 Mab in freshly excised kidneys from 7 patients with renal carcinoma. In all 7 cases, immunoscintigraphs showed the presence of well‐defined radioactive hot spots, which matched the positions of the tumors as identified by presurgery MRI scans and subsequent histopathologic examination. Importantly, in one instance, where a presurgery MRI scan had identified only one tumor, immunoscintigraphs showed 2 distinct hot spots of radioactivity. The pathology report confirmed that the additional hot spot corresponded to a small secondary well‐vascularized tumor. The implication of this finding is that the radiolabeled Mab, E9, may be of use in the detection of metastatic disease. That the labeling of tumors was specific was confirmed when prior perfusion of unlabeled mab E9 in 2 kidneys completely blocked the localization of 99Tcm‐conjugated Mab E9. Radioactivity in samples of tumor and normal tissue taken from 7 kidneys was counted in a gamma counter. In all cases, there was a greater uptake of radioactivity in tumors compared with the corresponding normal kidneys. The median values, adjusted per gram wet weight, for 99Tcm were 14.8 times (range, 4.8–113.0) greater in kidney tumors than in normal kidney tissue (p < 0.007). Immunofluorescent staining of cryostat sections of tumor tissues in each of the 7 cases showed strong and uniform localization of Mab E9 in tumor microvessels. Interestingly, chimeric staining of endothelial cells (ECs) was seen in an occasional microvessel segment. That is, while most of the ECs lining a microvessel were strongly stained, an occasional EC was negative. This was not an artifact of staining. Unstained ECs may be nonangiogenic or apoptotic since CD105 is a proliferation/activation‐associated antigen. Further investigations are warranted to establish the pharmacokinetics of 99Tcm‐labeled CD105 antibody in vivo. This would enable us to determine whether an apparently highly successful ex vivo study has the potential for tumor imaging/therapeutic vascular targeting in patients with cancer.

Imaging lung manifestations of HIV/AIDS.

Advances in our understanding of human immunodeficiency virus (HIV) infection have led to improved care and incremental increases in survival. However, the pulmonary manifestations of HIV/acquired immunodeficiency syndrome (AIDS) remain a major cause of morbidity and mortality. Respiratory complaints are not infrequent in patients who are HIV positive. The great majority of lung complications of HIV/AIDS are of infectious etiology but neoplasm, interstitial pneumonias, Kaposi sarcoma and lymphomas add significantly to patient morbidity and mortality. Imaging plays a vital role in the diagnosis and management of lung of complications associated with HIV. Accurate diagnosis is based on an understanding of the pathogenesis of the processes involved and their imaging findings. Imaging also plays an important role in selection of the most appropriate site for tissue sampling, staging of disease and follow-ups. We present images of lung manifestations of HIV/AIDS, describing the salient features and the differential diagnosis.

Sonography of hepatobiliary ascariasis.

We present the real‐time sonographic features of 19 surgically proven cases of hepatobiliary ascariasis, in which ultrasound examination was the primary modality used to achieve the diagnosis. All the patients presented with right upper quadrant abdominal symptoms. There were no false positive diagnoses. The “impacted worm” sign, reported here for the first time, presented in two patients as long curved, tubular, non‐shadowing structures with echoluscent cores, in the distribution of the intrahepatic biliary ducts. Both of these patients died soon after surgery indicating poor prognosis in such cases. Two other patients are described in whom macerated round worms were seen as intraluminal, localized, soft tissue masses in the common duct mimicking a cholangiocarcinoma. Thus, biliary ascariasis must be added to the differential diagnosis of an intraluminal bile duct mass in patients from endemic areas.

Image perception and interpretation of abnormalities; can we believe our eyes? Can we do something about it?

The radiologist’s visual impression of images is transmitted, via non-visual means (the report), to the clinician. There are several complex steps from the perception of the images by the radiologist to the understanding of the impression by the clinician. With a process as complex as this, it is no wonder that errors in perception, cognition, interpretation, transmission and understanding are very common. This paper reviews the processes of perception and error generation and possible strategies for minimising them.

Sonographic Mimics of Renal Calculi

Objectives. To review sonographic findings that can mimic renal calculi. Methods. We comment on a number of echoes that can mimic renal calculi. Results. There are a number of sonographic renal artifacts, vascular and nonvascular, that may confound a correct diagnosis. Conclusions. Awareness of these potential artifacts will result in a more specific sonographic examination and will accurately guide the referring physician toward appropriate patient treatment. The importance of other imaging modalities is also emphasized to ensure that a correct diagnosis is obtained whenever the sonographic findings are inconclusive.

Solitary pulmonary nodule: A diagnostic algorithm in the light of current imaging technique

The solitary pulmonary nodule (SPN) is frequently seen on chest radiographs and computed tomography (CT). The finding of a SPN usually provokes a flurry of clinical and imaging activity as an SPN in at-risk population is an alert signal of possible lung cancer. The frequency of malignant nodules in a given population is variable and depends on the endemicity of granulomatous disease. The percentage of malignant nodules also rises when dealing with at-risk population. The problem is compounded by the fact that with the present generation of CT scanners, 1–2 mm nodules are discovered in approximately half of the smokers aged 50 years or older scanned. A variety of management approaches are applied in the work-up of SPN often requiring evaluation over a long period of time to establish a benign or malignant diagnosis. Comparison with previous imaging studies and morphologic evaluation of the size, margins, and internal characteristics are usually the first step in the evaluation of these nodules. It is often necessary to use additional imaging techniques and occasionally invasive procedures such a percutaneous needle lung or a surgical biopsy. Until recently, the guidelines for follow-up of indeterminate noncalcified nodules detected on nonscreening CT was a minimum of 2 years. However, during the past few years due to further refinements in CT technology and better understanding of tumor behavior, it has prompted a revision of the guidelines of the follow-up of small indeterminate nodules. These guidelines have been endorsed by the Fleischner Society.

Sonographic features of mucinous biliary papillomatosis : Case report and review of imaging findings

Because of its indolent course, high recurrence rate, and risk of malignant transformation, mucinous biliary papillomatosis is an important consideration in the differential diagnosis of bile duct obstruction. We report a case of mucinous biliary papillomatosis and review the sonographic and other imaging findings previously reported in the literature. On sonography, these tumors appear as nonshadowing intrabiliary masses that are clearly defined and associated with proximal biliary dilatation. They may be multiple and associated with mucoid sludge. The imaging findings reflect the macroscopic appearance of a doughy papilliferous tumor of a bile duct. Associated findings include cholelithiasis, choledocholithiasis, and gallbladder dysplasia.

Bronchopulmonary aspergillosis: a review.

Pulmonary aspergillosis is a spectrum of lung diseases caused by the fungus Aspergillus, usually Aspergillus fumigatus. This intensely antigenic fungus is ubiquitous in the environment worldwide; it is commonly found in the sputum of healthy individuals, but has the ability to cause significant disease in susceptible hosts. The development of disease and its clinical, radiological, and histological manifestations depend on the virulence and number of spores inhaled and, more importantly, on the patient’s immune status and the presence or otherwise of chronic underlying lung disease. Four distinct forms of Pulmonary aspergillosis are recognized: 1) allergic bronchopulmonary aspergillosis (ABPA), which is caused by a hypersensitivity reaction toward the fungus, most commonly seen in asthmatics; 2) saprophytic aspergillosis (aspergilloma), the commonest form, which is noninvasive and involves colonization of pre-existing cavities; 3) chronic necrotising aspergillosis (also called airway-invasive or semi-invasive aspergillosis), which is a chronic cavitary pneumonic illness often affecting patients with pre-existing chronic lung disease; and 4) angioinvasive aspergillosis, which affects immunocompromised patients and is often fatal.